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Sample records for mixed-integer dynamic optimization

  1. Solving mixed integer nonlinear programming problems using spiral dynamics optimization algorithm

    NASA Astrophysics Data System (ADS)

    Kania, Adhe; Sidarto, Kuntjoro Adji

    2016-02-01

    Many engineering and practical problem can be modeled by mixed integer nonlinear programming. This paper proposes to solve the problem with modified spiral dynamics inspired optimization method of Tamura and Yasuda. Four test cases have been examined, including problem in engineering and sport. This method succeeds in obtaining the optimal result in all test cases.

  2. Mixed integer evolution strategies for parameter optimization.

    PubMed

    Li, Rui; Emmerich, Michael T M; Eggermont, Jeroen; Bäck, Thomas; Schütz, M; Dijkstra, J; Reiber, J H C

    2013-01-01

    Evolution strategies (ESs) are powerful probabilistic search and optimization algorithms gleaned from biological evolution theory. They have been successfully applied to a wide range of real world applications. The modern ESs are mainly designed for solving continuous parameter optimization problems. Their ability to adapt the parameters of the multivariate normal distribution used for mutation during the optimization run makes them well suited for this domain. In this article we describe and study mixed integer evolution strategies (MIES), which are natural extensions of ES for mixed integer optimization problems. MIES can deal with parameter vectors consisting not only of continuous variables but also with nominal discrete and integer variables. Following the design principles of the canonical evolution strategies, they use specialized mutation operators tailored for the aforementioned mixed parameter classes. For each type of variable, the choice of mutation operators is governed by a natural metric for this variable type, maximal entropy, and symmetry considerations. All distributions used for mutation can be controlled in their shape by means of scaling parameters, allowing self-adaptation to be implemented. After introducing and motivating the conceptual design of the MIES, we study the optimality of the self-adaptation of step sizes and mutation rates on a generalized (weighted) sphere model. Moreover, we prove global convergence of the MIES on a very general class of problems. The remainder of the article is devoted to performance studies on artificial landscapes (barrier functions and mixed integer NK landscapes), and a case study in the optimization of medical image analysis systems. In addition, we show that with proper constraint handling techniques, MIES can also be applied to classical mixed integer nonlinear programming problems. PMID:22122384

  3. Reverse engineering of logic-based differential equation models using a mixed-integer dynamic optimization approach

    PubMed Central

    Henriques, David; Rocha, Miguel; Saez-Rodriguez, Julio; Banga, Julio R.

    2015-01-01

    Motivation: Systems biology models can be used to test new hypotheses formulated on the basis of previous knowledge or new experimental data, contradictory with a previously existing model. New hypotheses often come in the shape of a set of possible regulatory mechanisms. This search is usually not limited to finding a single regulation link, but rather a combination of links subject to great uncertainty or no information about the kinetic parameters. Results: In this work, we combine a logic-based formalism, to describe all the possible regulatory structures for a given dynamic model of a pathway, with mixed-integer dynamic optimization (MIDO). This framework aims to simultaneously identify the regulatory structure (represented by binary parameters) and the real-valued parameters that are consistent with the available experimental data, resulting in a logic-based differential equation model. The alternative to this would be to perform real-valued parameter estimation for each possible model structure, which is not tractable for models of the size presented in this work. The performance of the method presented here is illustrated with several case studies: a synthetic pathway problem of signaling regulation, a two-component signal transduction pathway in bacterial homeostasis, and a signaling network in liver cancer cells. Supplementary information: Supplementary data are available at Bioinformatics online. Contact: julio@iim.csic.es or saezrodriguez@ebi.ac.uk PMID:26002881

  4. Toward the development of a Trust-Tech-based methodology for solving mixed integer nonlinear optimization

    NASA Astrophysics Data System (ADS)

    Wang, Bin; Chiang, Hsiao-Dong

    Many applications of smart grid can be formulated as constrained optimization problems. Because of the discrete controls involved in power systems, these problems are essentially mixed-integer nonlinear programs. In this paper, we review the Trust-Tech-based methodology for solving mixed-integer nonlinear optimization. Specifically, we have developed a two-stage Trust-Tech-based methodology to systematically compute all the local optimal solutions for constrained mixed-integer nonlinear programming (MINLP) problems. In the first stage, for a given MINLP problem this methodology starts with the construction of a new, continuous, unconstrained problem through relaxation and the penalty function method. A corresponding dynamical system is then constructed to search for a set of local optimal solutions for the unconstrained problem. In the second stage, a reduced constrained NLP is defined for each local optimal solution by determining and fixing the values of integral variables of the MINLP problem. The Trust-Tech-based method is used to compute a set of local optimal solutions for these reduced NLP problems, from which the optimal solution of the original MINLP problem is determined. A numerical simulation of several testing problems is provided to illustrate the effectiveness of our proposed method.

  5. Mixed integer model for optimizing equipment scheduling and overburden transport in a surface coal mining operation

    SciTech Connect

    Goodman, G.V.R.

    1987-01-01

    The lack of available techniques prompted the development of a mixed integer model to optimize the scheduling of equipment and the distribution of overburden in a typical mountaintop removal operation. Using this format, a (0-1) integer model and transportation model were constructed to determine the optimal equipment schedule and optimal overburden distribution, respectively. To solve this mixed integer program, the model was partitioned into its binary and real-valued components. Each problem was successively solved and their values added to form estimates of the value of the mixed integer program. Optimal convergence was indicated when the difference between two successive estimates satisfied some pre-specific accuracy value. The performance of the mixed integer model was tested against actual field data to determine its practical applications. To provide the necessary input information, production data was obtained from a single seam, mountaintop removal operation located in the Appalachian coal field. As a means of analyzing the resultant equipment schedule, the total idle time was calculated for each machine type and each lift location. Also, the final overburden assignments were analyzed by determining the distribution of spoil material for various overburden removal productivities. Subsequent validation of the mixed integer model was conducted in two distinct areas. The first dealt with changes in algorithmic data and their effects on the optimality of the model. The second area concerned variations in problem structure, specifically those dealing with changes in problem size and other user-inputed values such as equipment productivities or required reclamation.

  6. Enhanced index tracking modeling in portfolio optimization with mixed-integer programming z approach

    NASA Astrophysics Data System (ADS)

    Siew, Lam Weng; Jaaman, Saiful Hafizah Hj.; Ismail, Hamizun bin

    2014-09-01

    Enhanced index tracking is a popular form of portfolio management in stock market investment. Enhanced index tracking aims to construct an optimal portfolio to generate excess return over the return achieved by the stock market index without purchasing all of the stocks that make up the index. The objective of this paper is to construct an optimal portfolio using mixed-integer programming model which adopts regression approach in order to generate higher portfolio mean return than stock market index return. In this study, the data consists of 24 component stocks in Malaysia market index which is FTSE Bursa Malaysia Kuala Lumpur Composite Index from January 2010 until December 2012. The results of this study show that the optimal portfolio of mixed-integer programming model is able to generate higher mean return than FTSE Bursa Malaysia Kuala Lumpur Composite Index return with only selecting 30% out of the total stock market index components.

  7. Optimization of a wood dryer kiln using the mixed integer programming technique: A case study

    SciTech Connect

    Gustafsson, S.I.

    1999-07-01

    When wood is to be utilized as a raw material for furniture, buildings, etc., it must be dried from approximately 100% to 6% moisture content. This is achieved at least partly in a drying kiln. Heat for this purpose is provided by electrical means, or by steam from boilers fired with wood chips or oil. By making a close examination of monitored values from an actual drying kiln it has been possible to optimize the use of steam and electricity using the so called mixed integer programming technique. Owing to the operating schedule for the drying kiln it has been necessary to divide the drying process in very short time intervals, i.e., a number of minutes. Since a drying cycle takes about two or three weeks, a considerable mathematical problem is presented and this has to be solved.

  8. A Mixed-Integer Optimization Framework for De Novo Peptide Identification

    PubMed Central

    DiMaggio, Peter A.

    2009-01-01

    A novel methodology for the de novo identification of peptides by mixed-integer optimization and tandem mass spectrometry is presented in this article. The various features of the mathematical model are presented and examples are used to illustrate the key concepts of the proposed approach. Several problems are examined to illustrate the proposed method's ability to address (1) residue-dependent fragmentation properties and (2) the variability of resolution in different mass analyzers. A preprocessing algorithm is used to identify important m/z values in the tandem mass spectrum. Missing peaks, resulting from residue-dependent fragmentation characteristics, are dealt with using a two-stage algorithmic framework. A cross-correlation approach is used to resolve missing amino acid assignments and to identify the most probable peptide by comparing the theoretical spectra of the candidate sequences that were generated from the MILP sequencing stages with the experimental tandem mass spectrum. PMID:19412358

  9. Passenger-Oriented Optimization for Train Rescheduling on the Basis of Mixed Integer Programming

    NASA Astrophysics Data System (ADS)

    Chigusa, Kenji; Sato, Keisuke; Koseki, Takafumi

    Whenever there is a disruption in areas with a high frequency of train operations, the delays of trains propagate and train passengers have to suffer inconvenience. A rescheduling of the train operations is then conducted by train dispatchers to revert to the original operational plan. The task is quite difficult and a severe burden for the dispatchers because of a variety of options for reverting to the original plan, the necessity for a swift action, and the absence of a proper evaluation criterion. Consequently, a computer-aided rescheduling-support system is required. In this paper, we present a mathematical programming approach for train rescheduling, focusing on minimizing the passengers' arrival delay at their destinations. We simultaneously model the train operations and passenger flow on the basis of mixed integer programming (MIP), and we obtain an optimal rescheduling plan in reasonable time in the case of a small disruption.

  10. Optimization of the Thermosetting Pultrusion Process by Using Hybrid and Mixed Integer Genetic Algorithms

    NASA Astrophysics Data System (ADS)

    Baran, Ismet; Tutum, Cem C.; Hattel, Jesper H.

    2013-08-01

    In this paper thermo-chemical simulation of the pultrusion process of a composite rod is first used as a validation case to ensure that the utilized numerical scheme is stable and converges to results given in literature. Following this validation case, a cylindrical die block with heaters is added to the pultrusion domain of a composite part and thermal contact resistance (TCR) regions at the die-part interface are defined. Two optimization case studies are performed on this new configuration. In the first one, optimal die radius and TCR values are found by using a hybrid genetic algorithm based on a sequential combination of a genetic algorithm (GA) and a local search technique to fit the centerline temperature of the composite with the one calculated in the validation case. In the second optimization study, the productivity of the process is improved by using a mixed integer genetic algorithm (MIGA) such that the total number of heaters is minimized while satisfying the constraints for the maximum composite temperature, the mean of the cure degree at the die exit and the pulling speed.

  11. Designing cost-effective biopharmaceutical facilities using mixed-integer optimization.

    PubMed

    Liu, Songsong; Simaria, Ana S; Farid, Suzanne S; Papageorgiou, Lazaros G

    2013-01-01

    Chromatography operations are identified as critical steps in a monoclonal antibody (mAb) purification process and can represent a significant proportion of the purification material costs. This becomes even more critical with increasing product titers that result in higher mass loads onto chromatography columns, potentially causing capacity bottlenecks. In this work, a mixed-integer nonlinear programming (MINLP) model was created and applied to an industrially relevant case study to optimize the design of a facility by determining the most cost-effective chromatography equipment sizing strategies for the production of mAbs. Furthermore, the model was extended to evaluate the ability of a fixed facility to cope with higher product titers up to 15 g/L. Examination of the characteristics of the optimal chromatography sizing strategies across different titer values enabled the identification of the maximum titer that the facility could handle using a sequence of single column chromatography steps as well as multi-column steps. The critical titer levels for different ratios of upstream to dowstream trains where multiple parallel columns per step resulted in the removal of facility bottlenecks were identified. Different facility configurations in terms of number of upstream trains were considered and the trade-off between their cost and ability to handle higher titers was analyzed. The case study insights demonstrate that the proposed modeling approach, combining MINLP models with visualization tools, is a valuable decision-support tool for the design of cost-effective facility configurations and to aid facility fit decisions. 2013. PMID:23956206

  12. Industrial waste recycling strategies optimization problem: mixed integer programming model and heuristics

    NASA Astrophysics Data System (ADS)

    Tang, Jiafu; Liu, Yang; Fung, Richard; Luo, Xinggang

    2008-12-01

    Manufacturers have a legal accountability to deal with industrial waste generated from their production processes in order to avoid pollution. Along with advances in waste recovery techniques, manufacturers may adopt various recycling strategies in dealing with industrial waste. With reuse strategies and technologies, byproducts or wastes will be returned to production processes in the iron and steel industry, and some waste can be recycled back to base material for reuse in other industries. This article focuses on a recovery strategies optimization problem for a typical class of industrial waste recycling process in order to maximize profit. There are multiple strategies for waste recycling available to generate multiple byproducts; these byproducts are then further transformed into several types of chemical products via different production patterns. A mixed integer programming model is developed to determine which recycling strategy and which production pattern should be selected with what quantity of chemical products corresponding to this strategy and pattern in order to yield maximum marginal profits. The sales profits of chemical products and the set-up costs of these strategies, patterns and operation costs of production are considered. A simulated annealing (SA) based heuristic algorithm is developed to solve the problem. Finally, an experiment is designed to verify the effectiveness and feasibility of the proposed method. By comparing a single strategy to multiple strategies in an example, it is shown that the total sales profit of chemical products can be increased by around 25% through the simultaneous use of multiple strategies. This illustrates the superiority of combinatorial multiple strategies. Furthermore, the effects of the model parameters on profit are discussed to help manufacturers organize their waste recycling network.

  13. Mixed integer programming model for optimizing the layout of an ICU vehicle

    PubMed Central

    2009-01-01

    Background This paper presents a Mixed Integer Programming (MIP) model for designing the layout of the Intensive Care Units' (ICUs) patient care space. In particular, this MIP model was developed for optimizing the layout for materials to be used in interventions. This work was developed within the framework of a joint project between the Madrid Technical Unverstity and the Medical Emergency Services of the Madrid Regional Government (SUMMA 112). Methods The first task was to identify the relevant information to define the characteristics of the new vehicles and, in particular, to obtain a satisfactory interior layout to locate all the necessary materials. This information was gathered from health workers related to ICUs. With that information an optimization model was developed in order to obtain a solution. From the MIP model, a first solution was obtained, consisting of a grid to locate the different materials needed for the ICUs. The outcome from the MIP model was discussed with health workers to tune the solution, and after slightly altering that solution to meet some requirements that had not been included in the mathematical model, the eventual solution was approved by the persons responsible for specifying the characteristics of the new vehicles. According to the opinion stated by the SUMMA 112's medical group responsible for improving the ambulances (the so-called "coaching group"), the outcome was highly satisfactory. Indeed, the final design served as a basis to draw up the requirements of a public tender. Results As a result from solving the Optimization model, a grid was obtained to locate the different necessary materials for the ICUs. This grid had to be slightly altered to meet some requirements that had not been included in the mathematical model. The results were discussed with the persons responsible for specifying the characteristics of the new vehicles. Conclusion The outcome was highly satisfactory. Indeed, the final design served as a basis to draw up the requirements of a public tender. The authors advocate this approach to address similar problems within the field of Health Services to improve the efficiency and the effectiveness of the processes involved. Problems such as those in operation rooms or emergency rooms, where the availability of a large amount of material is critical are eligible to be dealt with in a simmilar manner. PMID:19995438

  14. Piece-wise mixed integer programming for optimal sizing of surge control devices in water distribution systems

    NASA Astrophysics Data System (ADS)

    Skulovich, Olya; Bent, Russell; Judi, David; Perelman, Lina Sela; Ostfeld, Avi

    2015-06-01

    Despite their potential catastrophic impact, transients are often ignored or presented ad hoc when designing water distribution systems. To address this problem, we introduce a new piece-wise function fitting model that is integrated with mixed integer programming to optimally place and size surge tanks for transient control. The key features of the algorithm are a model-driven discretization of the search space, a linear approximation nonsmooth system response surface to transients, and a mixed integer linear programming optimization. Results indicate that high quality solutions can be obtained within a reasonable number of function evaluations and demonstrate the computational effectiveness of the approach through two case studies. The work investigates one type of surge control devices (closed surge tank) for a specified set of transient events. The performance of the algorithm relies on the assumption that there exists a smooth relationship between the objective function and tank size. Results indicate the potential of the approach for the optimal surge control design in water systems.

  15. Optimal fleetwide emissions reductions for passenger ferries: an application of a mixed-integer nonlinear programming model for the New York-New Jersey Harbor.

    PubMed

    Winebrake, James J; Corbett, James J; Wang, Chengfeng; Farrell, Alexander E; Woods, Pippa

    2005-04-01

    Emissions from passenger ferries operating in urban harbors may contribute significantly to emissions inventories and commuter exposure to air pollution. In particular, ferries are problematic because of high emissions of oxides of nitrogen (NOx) and particulate matter (PM) from primarily unregulated diesel engines. This paper explores technical solutions to reduce pollution from passenger ferries operating in the New York-New Jersey Harbor. The paper discusses and demonstrates a mixed-integer, non-linear programming model used to identify optimal control strategies for meeting NOx and PM reduction targets for 45 privately owned commuter ferries in the harbor. Results from the model can be used by policy-makers to craft programs aimed at achieving least-cost reduction targets. PMID:15887889

  16. Mixed Integer Programming and Heuristic Scheduling for Space Communication Networks

    NASA Technical Reports Server (NTRS)

    Cheung, Kar-Ming; Lee, Charles H.

    2012-01-01

    We developed framework and the mathematical formulation for optimizing communication network using mixed integer programming. The design yields a system that is much smaller, in search space size, when compared to the earlier approach. Our constrained network optimization takes into account the dynamics of link performance within the network along with mission and operation requirements. A unique penalty function is introduced to transform the mixed integer programming into the more manageable problem of searching in a continuous space. The constrained optimization problem was proposed to solve in two stages: first using the heuristic Particle Swarming Optimization algorithm to get a good initial starting point, and then feeding the result into the Sequential Quadratic Programming algorithm to achieve the final optimal schedule. We demonstrate the above planning and scheduling methodology with a scenario of 20 spacecraft and 3 ground stations of a Deep Space Network site. Our approach and framework have been simple and flexible so that problems with larger number of constraints and network can be easily adapted and solved.

  17. Optimal planning of co-firing alternative fuels with coal in a power plant by grey nonlinear mixed integer programming model.

    PubMed

    Ko, Andi Setiady; Chang, Ni-Bin

    2008-07-01

    Energy supply and use is of fundamental importance to society. Although the interactions between energy and environment were originally local in character, they have now widened to cover regional and global issues, such as acid rain and the greenhouse effect. It is for this reason that there is a need for covering the direct and indirect economic and environmental impacts of energy acquisition, transport, production and use. In this paper, particular attention is directed to ways of resolving conflict between economic and environmental goals by encouraging a power plant to consider co-firing biomass and refuse-derived fuel (RDF) with coal simultaneously. It aims at reducing the emission level of sulfur dioxide (SO(2)) in an uncertain environment, using the power plant in Michigan City, Indiana as an example. To assess the uncertainty by a comparative way both deterministic and grey nonlinear mixed integer programming (MIP) models were developed to minimize the net operating cost with respect to possible fuel combinations. It aims at generating the optimal portfolio of alternative fuels while maintaining the same electricity generation simultaneously. To ease the solution procedure stepwise relaxation algorithm was developed for solving the grey nonlinear MIP model. Breakeven alternative fuel value can be identified in the post-optimization stage for decision-making. Research findings show that the inclusion of RDF does not exhibit comparative advantage in terms of the net cost, albeit relatively lower air pollution impact. Yet it can be sustained by a charge system, subsidy program, or emission credit as the price of coal increases over time. PMID:17395362

  18. Mixed Integer Programming and Heuristic Scheduling for Space Communication

    NASA Technical Reports Server (NTRS)

    Lee, Charles H.; Cheung, Kar-Ming

    2013-01-01

    Optimal planning and scheduling for a communication network was created where the nodes within the network are communicating at the highest possible rates while meeting the mission requirements and operational constraints. The planning and scheduling problem was formulated in the framework of Mixed Integer Programming (MIP) to introduce a special penalty function to convert the MIP problem into a continuous optimization problem, and to solve the constrained optimization problem using heuristic optimization. The communication network consists of space and ground assets with the link dynamics between any two assets varying with respect to time, distance, and telecom configurations. One asset could be communicating with another at very high data rates at one time, and at other times, communication is impossible, as the asset could be inaccessible from the network due to planetary occultation. Based on the network's geometric dynamics and link capabilities, the start time, end time, and link configuration of each view period are selected to maximize the communication efficiency within the network. Mathematical formulations for the constrained mixed integer optimization problem were derived, and efficient analytical and numerical techniques were developed to find the optimal solution. By setting up the problem using MIP, the search space for the optimization problem is reduced significantly, thereby speeding up the solution process. The ratio of the dimension of the traditional method over the proposed formulation is approximately an order N (single) to 2*N (arraying), where N is the number of receiving antennas of a node. By introducing a special penalty function, the MIP problem with non-differentiable cost function and nonlinear constraints can be converted into a continuous variable problem, whose solution is possible.

  19. Mixed-Integer Formulations for Constellation Scheduling

    NASA Astrophysics Data System (ADS)

    Valicka, C.; Hart, W.; Rintoul, M.

    Remote sensing systems have expanded the set of capabilities available for and critical to national security. Cooperating, high-fidelity sensing systems and growing mission applications have exponentially increased the set of potential schedules. A definitive lack of advanced tools places an increased burden on operators, as planning and scheduling remain largely manual tasks. This is particularly true in time-critical planning activities where operators aim to accomplish a large number of missions through optimal utilization of single or multiple sensor systems. Automated scheduling through identification and comparison of alternative schedules remains a challenging problem applicable across all remote sensing systems. Previous approaches focused on a subset of sensor missions and do not consider ad-hoc tasking. We have begun development of a robust framework that leverages the Pyomo optimization modeling language for the design of a tool to assist sensor operators planning under the constraints of multiple concurrent missions and uncertainty. Our scheduling models have been formulated to address the stochastic nature of ad-hoc tasks inserted under a variety of scenarios. Operator experience is being leveraged to select appropriate model objectives. Successful development of the framework will include iterative development of high-fidelity mission models that consider and expose various schedule performance metrics. Creating this tool will aid time-critical scheduling by increasing planning efficiency, clarifying the value of alternative modalities uniquely provided by multi-sensor systems, and by presenting both sets of organized information to operators. Such a tool will help operators more quickly and fully utilize sensing systems, a high interest objective within the current remote sensing operations community. Preliminary results for mixed-integer programming formulations of a sensor scheduling problem will be presented. Assumptions regarding sensor geometry and sensing activity time constraints, durations, priorities, etc. will be outlined. Finally, solver speed and stochastic programming details for uncertain activities and scheduling impediments will be discussed.

  20. Optimized oral cholera vaccine distribution strategies to minimize disease incidence: A mixed integer programming model and analysis of a Bangladesh scenario.

    PubMed

    Smalley, Hannah K; Keskinocak, Pinar; Swann, Julie; Hinman, Alan

    2015-11-17

    In addition to improved sanitation, hygiene, and better access to safe water, oral cholera vaccines can help to control the spread of cholera in the short term. However, there is currently no systematic method for determining the best allocation of oral cholera vaccines to minimize disease incidence in a population where the disease is endemic and resources are limited. We present a mathematical model for optimally allocating vaccines in a region under varying levels of demographic and incidence data availability. The model addresses the questions of where, when, and how many doses of vaccines to send. Considering vaccine efficacies (which may vary based on age and the number of years since vaccination), we analyze distribution strategies which allocate vaccines over multiple years. Results indicate that, given appropriate surveillance data, targeting age groups and regions with the highest disease incidence should be the first priority, followed by other groups primarily in order of disease incidence, as this approach is the most life-saving and cost-effective. A lack of detailed incidence data results in distribution strategies which are not cost-effective and can lead to thousands more deaths from the disease. The mathematical model allows for what-if analysis for various vaccine distribution strategies by providing the ability to easily vary parameters such as numbers and sizes of regions and age groups, risk levels, vaccine price, vaccine efficacy, production capacity and budget. PMID:26458806

  1. Fast scaffolding with small independent mixed integer programs

    PubMed Central

    Salmela, Leena; Mäkinen, Veli; Välimäki, Niko; Ylinen, Johannes; Ukkonen, Esko

    2011-01-01

    Motivation: Assembling genomes from short read data has become increasingly popular, but the problem remains computationally challenging especially for larger genomes. We study the scaffolding phase of sequence assembly where preassembled contigs are ordered based on mate pair data. Results: We present MIP Scaffolder that divides the scaffolding problem into smaller subproblems and solves these with mixed integer programming. The scaffolding problem can be represented as a graph and the biconnected components of this graph can be solved independently. We present a technique for restricting the size of these subproblems so that they can be solved accurately with mixed integer programming. We compare MIP Scaffolder to two state of the art methods, SOPRA and SSPACE. MIP Scaffolder is fast and produces better or as good scaffolds as its competitors on large genomes. Availability: The source code of MIP Scaffolder is freely available at http://www.cs.helsinki.fi/u/lmsalmel/mip-scaffolder/. Contact: leena.salmela@cs.helsinki.fi PMID:21998153

  2. Multi-objective mixed integer strategy for the optimisation of biological networks.

    PubMed

    Sendín, J O H; Exler, O; Banga, J R

    2010-05-01

    In this contribution, the authors consider multi-criteria optimisation problems arising from the field of systems biology when both continuous and integer decision variables are involved. Mathematically, they are formulated as mixed-integer non-linear programming problems. The authors present a novel solution strategy based on a global optimisation approach for dealing with this class of problems. Its usefulness and capabilities are illustrated with two metabolic engineering case studies. For these problems, the authors show how the set of optimal solutions (the so-called Pareto front) is successfully and efficiently obtained, providing further insight into the systems under consideration regarding their optimal manipulation. PMID:20500003

  3. PySP : modeling and solving stochastic mixed-integer programs in Python.

    SciTech Connect

    Woodruff, David L.; Watson, Jean-Paul

    2010-08-01

    Although stochastic programming is a powerful tool for modeling decision-making under uncertainty, various impediments have historically prevented its widespread use. One key factor involves the ability of non-specialists to easily express stochastic programming problems as extensions of deterministic models, which are often formulated first. A second key factor relates to the difficulty of solving stochastic programming models, particularly the general mixed-integer, multi-stage case. Intricate, configurable, and parallel decomposition strategies are frequently required to achieve tractable run-times. We simultaneously address both of these factors in our PySP software package, which is part of the COIN-OR Coopr open-source Python project for optimization. To formulate a stochastic program in PySP, the user specifies both the deterministic base model and the scenario tree with associated uncertain parameters in the Pyomo open-source algebraic modeling language. Given these two models, PySP provides two paths for solution of the corresponding stochastic program. The first alternative involves writing the extensive form and invoking a standard deterministic (mixed-integer) solver. For more complex stochastic programs, we provide an implementation of Rockafellar and Wets Progressive Hedging algorithm. Our particular focus is on the use of Progressive Hedging as an effective heuristic for approximating general multi-stage, mixed-integer stochastic programs. By leveraging the combination of a high-level programming language (Python) and the embedding of the base deterministic model in that language (Pyomo), we are able to provide completely generic and highly configurable solver implementations. PySP has been used by a number of research groups, including our own, to rapidly prototype and solve difficult stochastic programming problems.

  4. Item Pool Construction Using Mixed Integer Quadratic Programming (MIQP). GMAC® Research Report RR-14-01

    ERIC Educational Resources Information Center

    Han, Kyung T.; Rudner, Lawrence M.

    2014-01-01

    This study uses mixed integer quadratic programming (MIQP) to construct multiple highly equivalent item pools simultaneously, and compares the results from mixed integer programming (MIP). Three different MIP/MIQP models were implemented and evaluated using real CAT item pool data with 23 different content areas and a goal of equal information…

  5. Final Report---Next-Generation Solvers for Mixed-Integer Nonlinear Programs: Structure, Search, and Implementation

    SciTech Connect

    Linderoth, Jeff T.; Luedtke, James R.

    2013-05-30

    The mathematical modeling of systems often requires the use of both nonlinear and discrete components. Problems involving both discrete and nonlinear components are known as mixed-integer nonlinear programs (MINLPs) and are among the most challenging computational optimization problems. This research project added to the understanding of this area by making a number of fundamental advances. First, the work demonstrated many novel, strong, tractable relaxations designed to deal with non-convexities arising in mathematical formulation. Second, the research implemented the ideas in software that is available to the public. Finally, the work demonstrated the importance of these ideas on practical applications and disseminated the work through scholarly journals, survey publications, and conference presentations.

  6. Learning oncogenetic networks by reducing to mixed integer linear programming.

    PubMed

    Shahrabi Farahani, Hossein; Lagergren, Jens

    2013-01-01

    Cancer can be a result of accumulation of different types of genetic mutations such as copy number aberrations. The data from tumors are cross-sectional and do not contain the temporal order of the genetic events. Finding the order in which the genetic events have occurred and progression pathways are of vital importance in understanding the disease. In order to model cancer progression, we propose Progression Networks, a special case of Bayesian networks, that are tailored to model disease progression. Progression networks have similarities with Conjunctive Bayesian Networks (CBNs) [1],a variation of Bayesian networks also proposed for modeling disease progression. We also describe a learning algorithm for learning Bayesian networks in general and progression networks in particular. We reduce the hard problem of learning the Bayesian and progression networks to Mixed Integer Linear Programming (MILP). MILP is a Non-deterministic Polynomial-time complete (NP-complete) problem for which very good heuristics exists. We tested our algorithm on synthetic and real cytogenetic data from renal cell carcinoma. We also compared our learned progression networks with the networks proposed in earlier publications. The software is available on the website https://bitbucket.org/farahani/diprog. PMID:23799047

  7. Automatic design of synthetic gene circuits through mixed integer non-linear programming.

    PubMed

    Huynh, Linh; Kececioglu, John; Köppe, Matthias; Tagkopoulos, Ilias

    2012-01-01

    Automatic design of synthetic gene circuits poses a significant challenge to synthetic biology, primarily due to the complexity of biological systems, and the lack of rigorous optimization methods that can cope with the combinatorial explosion as the number of biological parts increases. Current optimization methods for synthetic gene design rely on heuristic algorithms that are usually not deterministic, deliver sub-optimal solutions, and provide no guaranties on convergence or error bounds. Here, we introduce an optimization framework for the problem of part selection in synthetic gene circuits that is based on mixed integer non-linear programming (MINLP), which is a deterministic method that finds the globally optimal solution and guarantees convergence in finite time. Given a synthetic gene circuit, a library of characterized parts, and user-defined constraints, our method can find the optimal selection of parts that satisfy the constraints and best approximates the objective function given by the user. We evaluated the proposed method in the design of three synthetic circuits (a toggle switch, a transcriptional cascade, and a band detector), with both experimentally constructed and synthetic promoter libraries. Scalability and robustness analysis shows that the proposed framework scales well with the library size and the solution space. The work described here is a step towards a unifying, realistic framework for the automated design of biological circuits. PMID:22536398

  8. Dynamic Optimization

    NASA Technical Reports Server (NTRS)

    Laird, Philip

    1992-01-01

    We distinguish static and dynamic optimization of programs: whereas static optimization modifies a program before runtime and is based only on its syntactical structure, dynamic optimization is based on the statistical properties of the input source and examples of program execution. Explanation-based generalization is a commonly used dynamic optimization method, but its effectiveness as a speedup-learning method is limited, in part because it fails to separate the learning process from the program transformation process. This paper describes a dynamic optimization technique called a learn-optimize cycle that first uses a learning element to uncover predictable patterns in the program execution and then uses an optimization algorithm to map these patterns into beneficial transformations. The technique has been used successfully for dynamic optimization of pure Prolog.

  9. A Mixed Integer Linear Program for Airport Departure Scheduling

    NASA Technical Reports Server (NTRS)

    Gupta, Gautam; Jung, Yoon Chul

    2009-01-01

    Aircraft departing from an airport are subject to numerous constraints while scheduling departure times. These constraints include wake-separation constraints for successive departures, miles-in-trail separation for aircraft bound for the same departure fixes, and time-window or prioritization constraints for individual flights. Besides these, emissions as well as increased fuel consumption due to inefficient scheduling need to be included. Addressing all the above constraints in a single framework while allowing for resequencing of the aircraft using runway queues is critical to the implementation of the Next Generation Air Transport System (NextGen) concepts. Prior work on airport departure scheduling has addressed some of the above. However, existing methods use pre-determined runway queues, and schedule aircraft from these departure queues. The source of such pre-determined queues is not explicit, and could potentially be a subjective controller input. Determining runway queues and scheduling within the same framework would potentially result in better scheduling. This paper presents a mixed integer linear program (MILP) for the departure-scheduling problem. The program takes as input the incoming sequence of aircraft for departure from a runway, along with their earliest departure times and an optional prioritization scheme based on time-window of departure for each aircraft. The program then assigns these aircraft to the available departure queues and schedules departure times, explicitly considering wake separation and departure fix restrictions to minimize total delay for all aircraft. The approach is generalized and can be used in a variety of situations, and allows for aircraft prioritization based on operational as well as environmental considerations. We present the MILP in the paper, along with benefits over the first-come-first-serve (FCFS) scheme for numerous randomized problems based on real-world settings. The MILP results in substantially reduced delays as compared to FCFS, and the magnitude of the savings depends on the queue and departure fix structure. The MILP assumes deterministic aircraft arrival times at the runway queues. However, due to taxi time uncertainty, aircraft might arrive either earlier or later than these deterministic times. Thus, to incorporate this uncertainty, we present a method for using the MILP with "overlap discounted rolling planning horizon". The approach is based on valuing near-term decision results more than future ones. We develop a model of taxitime uncertainty based on real-world data, and then compare the baseline FCFS delays with delays using the above MILP in a simple rolling-horizon method and in the overlap discounted scheme.

  10. High-Speed Planning Method for Cooperative Logistics Networks using Mixed Integer Programming Model and Dummy Load

    NASA Astrophysics Data System (ADS)

    Onoyama, Takashi; Kubota, Sen; Maekawa, Takuya; Komoda, Norihisa

    Adequate response performance is required for the planning of a cooperative logistic network covering multiple enterprises, because this process needs a human expert's evaluation from many aspects. To satisfy this requirement, we propose an accurate model based on mixed integer programming for optimizing cooperative logistics networks where “round transportation” exists together with “depot transportation” including lower limit constraints of loading ratio for round transportation vehicles. Furthermore, to achieve interactive response performance, a dummy load is introduced into the model instead of integer variables. The experimental result shows the proposed method obtains an accurate solution within interactive response time.

  11. A Mixed Integer Linear Program for Solving a Multiple Route Taxi Scheduling Problem

    NASA Technical Reports Server (NTRS)

    Montoya, Justin Vincent; Wood, Zachary Paul; Rathinam, Sivakumar; Malik, Waqar Ahmad

    2010-01-01

    Aircraft movements on taxiways at busy airports often create bottlenecks. This paper introduces a mixed integer linear program to solve a Multiple Route Aircraft Taxi Scheduling Problem. The outputs of the model are in the form of optimal taxi schedules, which include routing decisions for taxiing aircraft. The model extends an existing single route formulation to include routing decisions. An efficient comparison framework compares the multi-route formulation and the single route formulation. The multi-route model is exercised for east side airport surface traffic at Dallas/Fort Worth International Airport to determine if any arrival taxi time savings can be achieved by allowing arrivals to have two taxi routes: a route that crosses an active departure runway and a perimeter route that avoids the crossing. Results indicate that the multi-route formulation yields reduced arrival taxi times over the single route formulation only when a perimeter taxiway is used. In conditions where the departure aircraft are given an optimal and fixed takeoff sequence, accumulative arrival taxi time savings in the multi-route formulation can be as high as 3.6 hours more than the single route formulation. If the departure sequence is not optimal, the multi-route formulation results in less taxi time savings made over the single route formulation, but the average arrival taxi time is significantly decreased.

  12. A Two-Stage Stochastic Mixed-Integer Programming Approach to the Smart House Scheduling Problem

    NASA Astrophysics Data System (ADS)

    Ozoe, Shunsuke; Tanaka, Yoichi; Fukushima, Masao

    A “Smart House” is a highly energy-optimized house equipped with photovoltaic systems (PV systems), electric battery systems, fuel cell cogeneration systems (FC systems), electric vehicles (EVs) and so on. Smart houses are attracting much attention recently thanks to their enhanced ability to save energy by making full use of renewable energy and by achieving power grid stability despite an increased power draw for installed PV systems. Yet running a smart house's power system, with its multiple power sources and power storages, is no simple task. In this paper, we consider the problem of power scheduling for a smart house with a PV system, an FC system and an EV. We formulate the problem as a mixed integer programming problem, and then extend it to a stochastic programming problem involving recourse costs to cope with uncertain electricity demand, heat demand and PV power generation. Using our method, we seek to achieve the optimal power schedule running at the minimum expected operation cost. We present some results of numerical experiments with data on real-life demands and PV power generation to show the effectiveness of our method.

  13. Synchronic interval Gaussian mixed-integer programming for air quality management.

    PubMed

    Cheng, Guanhui; Huang, Guohe Gordon; Dong, Cong

    2015-12-15

    To reveal the synchronism of interval uncertainties, the tradeoff between system optimality and security, the discreteness of facility-expansion options, the uncertainty of pollutant dispersion processes, and the seasonality of wind features in air quality management (AQM) systems, a synchronic interval Gaussian mixed-integer programming (SIGMIP) approach is proposed in this study. A robust interval Gaussian dispersion model is developed for approaching the pollutant dispersion process under interval uncertainties and seasonal variations. The reflection of synchronic effects of interval uncertainties in the programming objective is enabled through introducing interval functions. The proposition of constraint violation degrees helps quantify the tradeoff between system optimality and constraint violation under interval uncertainties. The overall optimality of system profits of an SIGMIP model is achieved based on the definition of an integrally optimal solution. Integer variables in the SIGMIP model are resolved by the existing cutting-plane method. Combining these efforts leads to an effective algorithm for the SIGMIP model. An application to an AQM problem in a region in Shandong Province, China, reveals that the proposed SIGMIP model can facilitate identifying the desired scheme for AQM. The enhancement of the robustness of optimization exercises may be helpful for increasing the reliability of suggested schemes for AQM under these complexities. The interrelated tradeoffs among control measures, emission sources, flow processes, receptors, influencing factors, and economic and environmental goals are effectively balanced. Interests of many stakeholders are reasonably coordinated. The harmony between economic development and air quality control is enabled. Results also indicate that the constraint violation degree is effective at reflecting the compromise relationship between constraint-violation risks and system optimality under interval uncertainties. This can help decision makers mitigate potential risks, e.g. insufficiency of pollutant treatment capabilities, exceedance of air quality standards, deficiency of pollution control fund, or imbalance of economic or environmental stress, in the process of guiding AQM. PMID:26367068

  14. Mixed Integer Programming and Heuristic Scheduling for Space Communication Networks

    NASA Technical Reports Server (NTRS)

    Lee, Charles H.; Cheung, Kar-Ming

    2012-01-01

    In this paper, we propose to solve the constrained optimization problem in two phases. The first phase uses heuristic methods such as the ant colony method, particle swarming optimization, and genetic algorithm to seek a near optimal solution among a list of feasible initial populations. The final optimal solution can be found by using the solution of the first phase as the initial condition to the SQP algorithm. We demonstrate the above problem formulation and optimization schemes with a large-scale network that includes the DSN ground stations and a number of spacecraft of deep space missions.

  15. Solution of Mixed-Integer Programming Problems on the XT5

    SciTech Connect

    Hartman-Baker, Rebecca J; Busch, Ingrid Karin; Hilliard, Michael R; Middleton, Richard S; Schultze, Michael

    2009-01-01

    In this paper, we describe our experience with solving difficult mixed-integer linear programming problems (MILPs) on the petaflop Cray XT5 system at the National Center for Computational Sciences at Oak Ridge National Laboratory. We describe the algorithmic, software, and hardware needs for solving MILPs and present the results of using PICO, an open-source, parallel, mixed-integer linear programming solver developed at Sandia National Laboratories, to solve canonical MILPs as well as problems of interest arising from the logistics and supply chain management field.

  16. An inexact fuzzy-chance-constrained two-stage mixed-integer linear programming approach for flood diversion planning under multiple uncertainties

    NASA Astrophysics Data System (ADS)

    Guo, P.; Huang, G. H.; Li, Y. P.

    2010-01-01

    In this study, an inexact fuzzy-chance-constrained two-stage mixed-integer linear programming (IFCTIP) approach is developed for flood diversion planning under multiple uncertainties. A concept of the distribution with fuzzy boundary interval probability is defined to address multiple uncertainties expressed as integration of intervals, fuzzy sets and probability distributions. IFCTIP integrates the inexact programming, two-stage stochastic programming, integer programming and fuzzy-stochastic programming within a general optimization framework. IFCTIP incorporates the pre-regulated water-diversion policies directly into its optimization process to analyze various policy scenarios; each scenario has different economic penalty when the promised targets are violated. More importantly, it can facilitate dynamic programming for decisions of capacity-expansion planning under fuzzy-stochastic conditions. IFCTIP is applied to a flood management system. Solutions from IFCTIP provide desired flood diversion plans with a minimized system cost and a maximized safety level. The results indicate that reasonable solutions are generated for objective function values and decision variables, thus a number of decision alternatives can be generated under different levels of flood flows.

  17. Interval-parameter semi-infinite fuzzy-stochastic mixed-integer programming approach for environmental management under multiple uncertainties

    SciTech Connect

    Guo, P.; Huang, G.H.

    2010-03-15

    In this study, an interval-parameter semi-infinite fuzzy-chance-constrained mixed-integer linear programming (ISIFCIP) approach is developed for supporting long-term planning of waste-management systems under multiple uncertainties in the City of Regina, Canada. The method improves upon the existing interval-parameter semi-infinite programming (ISIP) and fuzzy-chance-constrained programming (FCCP) by incorporating uncertainties expressed as dual uncertainties of functional intervals and multiple uncertainties of distributions with fuzzy-interval admissible probability of violating constraint within a general optimization framework. The binary-variable solutions represent the decisions of waste-management-facility expansion, and the continuous ones are related to decisions of waste-flow allocation. The interval solutions can help decision-makers to obtain multiple decision alternatives, as well as provide bases for further analyses of tradeoffs between waste-management cost and system-failure risk. In the application to the City of Regina, Canada, two scenarios are considered. In Scenario 1, the City's waste-management practices would be based on the existing policy over the next 25 years. The total diversion rate for the residential waste would be approximately 14%. Scenario 2 is associated with a policy for waste minimization and diversion, where 35% diversion of residential waste should be achieved within 15 years, and 50% diversion over 25 years. In this scenario, not only landfill would be expanded, but also CF and MRF would be expanded. Through the scenario analyses, useful decision support for the City's solid-waste managers and decision-makers has been generated. Three special characteristics of the proposed method make it unique compared with other optimization techniques that deal with uncertainties. Firstly, it is useful for tackling multiple uncertainties expressed as intervals, functional intervals, probability distributions, fuzzy sets, and their combinations; secondly, it has capability in addressing the temporal variations of the functional intervals; thirdly, it can facilitate dynamic analysis for decisions of facility-expansion planning and waste-flow allocation within a multi-facility, multi-period and multi-option context.

  18. COMSAT: Residue contact prediction of transmembrane proteins based on support vector machines and mixed integer linear programming.

    PubMed

    Zhang, Huiling; Huang, Qingsheng; Bei, Zhendong; Wei, Yanjie; Floudas, Christodoulos A

    2016-03-01

    In this article, we present COMSAT, a hybrid framework for residue contact prediction of transmembrane (TM) proteins, integrating a support vector machine (SVM) method and a mixed integer linear programming (MILP) method. COMSAT consists of two modules: COMSAT_SVM which is trained mainly on position-specific scoring matrix features, and COMSAT_MILP which is an ab initio method based on optimization models. Contacts predicted by the SVM model are ranked by SVM confidence scores, and a threshold is trained to improve the reliability of the predicted contacts. For TM proteins with no contacts above the threshold, COMSAT_MILP is used. The proposed hybrid contact prediction scheme was tested on two independent TM protein sets based on the contact definition of 14 Å between Cα-Cα atoms. First, using a rigorous leave-one-protein-out cross validation on the training set of 90 TM proteins, an accuracy of 66.8%, a coverage of 12.3%, a specificity of 99.3% and a Matthews' correlation coefficient (MCC) of 0.184 were obtained for residue pairs that are at least six amino acids apart. Second, when tested on a test set of 87 TM proteins, the proposed method showed a prediction accuracy of 64.5%, a coverage of 5.3%, a specificity of 99.4% and a MCC of 0.106. COMSAT shows satisfactory results when compared with 12 other state-of-the-art predictors, and is more robust in terms of prediction accuracy as the length and complexity of TM protein increase. COMSAT is freely accessible at http://hpcc.siat.ac.cn/COMSAT/. Proteins 2016; 84:332-348. © 2016 Wiley Periodicals, Inc. PMID:26756402

  19. Mixed integer nonlinear programming model of wireless pricing scheme with QoS attribute of bandwidth and end-to-end delay

    NASA Astrophysics Data System (ADS)

    Irmeilyana, Puspita, Fitri Maya; Indrawati

    2016-02-01

    The pricing for wireless networks is developed by considering linearity factors, elasticity price and price factors. Mixed Integer Nonlinear Programming of wireless pricing model is proposed as the nonlinear programming problem that can be solved optimally using LINGO 13.0. The solutions are expected to give some information about the connections between the acceptance factor and the price. Previous model worked on the model that focuses on bandwidth as the QoS attribute. The models attempt to maximize the total price for a connection based on QoS parameter. The QoS attributes used will be the bandwidth and the end to end delay that affect the traffic. The maximum goal to maximum price is achieved when the provider determine the requirement for the increment or decrement of price change due to QoS change and amount of QoS value.

  20. A mixed integer bi-level DEA model for bank branch performance evaluation by Stackelberg approach

    NASA Astrophysics Data System (ADS)

    Shafiee, Morteza; Lotfi, Farhad Hosseinzadeh; Saleh, Hilda; Ghaderi, Mehdi

    2015-11-01

    One of the most complicated decision making problems for managers is the evaluation of bank performance, which involves various criteria. There are many studies about bank efficiency evaluation by network DEA in the literature review. These studies do not focus on multi-level network. Wu (Eur J Oper Res 207:856-864, 2010) proposed a bi-level structure for cost efficiency at the first time. In this model, multi-level programming and cost efficiency were used. He used a nonlinear programming to solve the model. In this paper, we have focused on multi-level structure and proposed a bi-level DEA model. We then used a liner programming to solve our model. In other hand, we significantly improved the way to achieve the optimum solution in comparison with the work by Wu (2010) by converting the NP-hard nonlinear programing into a mixed integer linear programming. This study uses a bi-level programming data envelopment analysis model that embodies internal structure with Stackelberg-game relationships to evaluate the performance of banking chain. The perspective of decentralized decisions is taken in this paper to cope with complex interactions in banking chain. The results derived from bi-level programming DEA can provide valuable insights and detailed information for managers to help them evaluate the performance of the banking chain as a whole using Stackelberg-game relationships. Finally, this model was applied in the Iranian bank to evaluate cost efficiency.

  1. A mixed integer bi-level DEA model for bank branch performance evaluation by Stackelberg approach

    NASA Astrophysics Data System (ADS)

    Shafiee, Morteza; Lotfi, Farhad Hosseinzadeh; Saleh, Hilda; Ghaderi, Mehdi

    2016-11-01

    One of the most complicated decision making problems for managers is the evaluation of bank performance, which involves various criteria. There are many studies about bank efficiency evaluation by network DEA in the literature review. These studies do not focus on multi-level network. Wu (Eur J Oper Res 207:856-864, 2010) proposed a bi-level structure for cost efficiency at the first time. In this model, multi-level programming and cost efficiency were used. He used a nonlinear programming to solve the model. In this paper, we have focused on multi-level structure and proposed a bi-level DEA model. We then used a liner programming to solve our model. In other hand, we significantly improved the way to achieve the optimum solution in comparison with the work by Wu (2010) by converting the NP-hard nonlinear programing into a mixed integer linear programming. This study uses a bi-level programming data envelopment analysis model that embodies internal structure with Stackelberg-game relationships to evaluate the performance of banking chain. The perspective of decentralized decisions is taken in this paper to cope with complex interactions in banking chain. The results derived from bi-level programming DEA can provide valuable insights and detailed information for managers to help them evaluate the performance of the banking chain as a whole using Stackelberg-game relationships. Finally, this model was applied in the Iranian bank to evaluate cost efficiency.

  2. Drawing and Labeling High-Quality Metro Maps by Mixed-Integer Programming.

    PubMed

    Nollenburg, M; Wolff, A

    2011-05-01

    Metro maps are schematic diagrams of public transport networks that serve as visual aids for route planning and navigation tasks. It is a challenging problem in network visualization to automatically draw appealing metro maps. There are two aspects to this problem that depend on each other: the layout problem of finding station and link coordinates and the labeling problem of placing nonoverlapping station labels. In this paper, we present a new integral approach that solves the combined layout and labeling problem (each of which, independently, is known to be NP-hard) using mixed-integer programming (MIP). We identify seven design rules used in most real-world metro maps. We split these rules into hard and soft constraints and translate them into an MIP model. Our MIP formulation finds a metro map that satisfies all hard constraints (if such a drawing exists) and minimizes a weighted sum of costs that correspond to the soft constraints. We have implemented the MIP model and present a case study and the results of an expert assessment to evaluate the performance of our approach in comparison to both manually designed official maps and results of previous layout methods. PMID:20498505

  3. Using a mixed integer linear programming technique to optimize a fracture treatment design

    SciTech Connect

    Rueda, J.I.; Rahim, Z.; Holditch, S.A.

    1994-12-31

    The design of the optimum fracture treatment has three basic steps. The first step involves calculating fracture dimensions and conductivity for various fracture fluid pumping schedules. The second step is determining the oil and gas production rates and recoveries using the values of propped fracture length obtained from the fracture treatment design. The third step requires one to determine the optimum fracture treatment design by maximizing the economic benefit of the treatment. Since a fracture treatment design involves selection of fracturing fluids, additives, proppant materials, injection rate, pump schedule, and fracture dimensions, the determination of the optimum combination of all variables can be quite complicated. In this research, the authors have developed two methods to investigate reasonable combinations of design and treatment parameters to determine the most profitable fracture treatment design. Depending upon the post-fracture treatment production rates, the related expenses, and the economic constraints, the optimum treatment can be easily determined.

  4. Mixed-integer programming methods for transportation and power generation problems

    NASA Astrophysics Data System (ADS)

    Damci Kurt, Pelin

    This dissertation conducts theoretical and computational research to solve challenging problems in application areas such as supply chain and power systems. The first part of the dissertation studies a transportation problem with market choice (TPMC) which is a variant of the classical transportation problem in which suppliers with limited capacities have a choice of which demands (markets) to satisfy. We show that TPMC is strongly NP-complete. We consider a version of the problem with a service level constraint on the maximum number of markets that can be rejected and show that if the original problem is polynomial, its cardinality-constrained version is also polynomial. We propose valid inequalities for mixed-integer cover and knapsack sets with variable upper bound constraints, which appear as substructures of TPMC and use them in a branch-and-cut algorithm to solve this problem. The second part of this dissertation studies a unit commitment (UC) problem in which the goal is to minimize the operational cost of power generators over a time period subject to physical constraints while satisfying demand. We provide several exponential classes of multi-period ramping and multi-period variable upper bound inequalities. We prove the strength of these inequalities and describe polynomial-time separation algorithms. Computational results show the effectiveness of the proposed inequalities when used as cuts in a branch-and-cut algorithm to solve the UC problem. The last part of this dissertation investigates the effects of uncertain wind power on the UC problem. A two-stage robust model and a three-stage stochastic program are compared.

  5. Multi-objective Mixed Integer Programming approach for facility layout design by considering closeness ratings, material handling, and re-layout cost

    NASA Astrophysics Data System (ADS)

    Purnomo, Muhammad Ridwan Andi; Satrio Wiwoho, Yoga

    2016-01-01

    Facility layout becomes one of production system factor that should be managed well, as it is designated for the location of production. In managing the layout, designing the layout by considering the optimal layout condition that supports the work condition is essential. One of the method for facility layout optimization is Mixed Integer Programming (MIP). In this study, the MIP is solved using Lingo 9.0 software and considering quantitative and qualitative objectives to be achieved simultaneously: minimizing material handling cost, maximizing closeness rating, and minimizing re-layout cost. The research took place in Rekayasa Wangdi as a make to order company, focusing on the making of concrete brick dough stirring machine with 10 departments involved. The result shows an improvement in the new layout for 333,72 points of objective value compared with the initial layout. As the conclusion, the proposed MIP is proven to be used to model facility layout problem under multi objective consideration for a more realistic look.

  6. A novel mixed integer programming for multi-biomarker panel identification by distinguishing malignant from benign colorectal tumors.

    PubMed

    Zou, Meng; Zhang, Peng-Jun; Wen, Xin-Yu; Chen, Luonan; Tian, Ya-Ping; Wang, Yong

    2015-07-15

    Multi-biomarker panels can capture the nonlinear synergy among biomarkers and they are important to aid in the early diagnosis and ultimately battle complex diseases. However, identification of these multi-biomarker panels from case and control data is challenging. For example, the exhaustive search method is computationally infeasible when the data dimension is high. Here, we propose a novel method, MILP_k, to identify serum-based multi-biomarker panel to distinguish colorectal cancers (CRC) from benign colorectal tumors. Specifically, the multi-biomarker panel detection problem is modeled by a mixed integer programming to maximize the classification accuracy. Then we measured the serum profiling data for 101 CRC patients and 95 benign patients. The 61 biomarkers were analyzed individually and further their combinations by our method. We discovered 4 biomarkers as the optimal small multi-biomarker panel, including known CRC biomarkers CEA and IL-10 as well as novel biomarkers IMA and NSE. This multi-biomarker panel obtains leave-one-out cross-validation (LOOCV) accuracy to 0.7857 by nearest centroid classifier. An independent test of this panel by support vector machine (SVM) with threefold cross validation gets an AUC 0.8438. This greatly improves the predictive accuracy by 20% over the single best biomarker. Further extension of this 4-biomarker panel to a larger 13-biomarker panel improves the LOOCV to 0.8673 with independent AUC 0.8437. Comparison with the exhaustive search method shows that our method dramatically reduces the searching time by 1000-fold. Experiments on the early cancer stage samples reveal two panel of biomarkers and show promising accuracy. The proposed method allows us to select the subset of biomarkers with best accuracy to distinguish case and control samples given the number of selected biomarkers. Both receiver operating characteristic curve and precision-recall curve show our method's consistent performance gain in accuracy. Our method also shows its advantage in capturing synergy among selected biomarkers. The multi-biomarker panel far outperforms the simple combination of best single features. Close investigation of the multi-biomarker panel illustrates that our method possesses the ability to remove redundancy and reveals complementary biomarker combinations. In addition, our method is efficient and can select multi-biomarker panel with more than 5 biomarkers, for which the exhaustive methods fail. In conclusion, we propose a promising model to improve the clinical data interpretability and to serve as a useful tool for other complex disease studies. Our small multi-biomarker panel, CEA, IL-10, IMA, and NSE, may provide insights on the disease status of colorectal diseases. The implementation of our method in MATLAB is available via the website: http://doc.aporc.org/wiki/MILP_k. PMID:25980368

  7. Final Report---Optimization Under Nonconvexity and Uncertainty: Algorithms and Software

    SciTech Connect

    Jeff Linderoth

    2011-11-06

    the goal of this work was to develop new algorithmic techniques for solving large-scale numerical optimization problems, focusing on problems classes that have proven to be among the most challenging for practitioners: those involving uncertainty and those involving nonconvexity. This research advanced the state-of-the-art in solving mixed integer linear programs containing symmetry, mixed integer nonlinear programs, and stochastic optimization problems. The focus of the work done in the continuation was on Mixed Integer Nonlinear Programs (MINLP)s and Mixed Integer Linear Programs (MILP)s, especially those containing a great deal of symmetry.

  8. Optimization of environmental management strategies through a dynamic stochastic possibilistic multiobjective program.

    PubMed

    Zhang, Xiaodong; Huang, Gordon

    2013-02-15

    Greenhouse gas (GHG) emissions from municipal solid waste (MSW) management facilities have become a serious environmental issue. In MSW management, not only economic objectives but also environmental objectives should be considered simultaneously. In this study, a dynamic stochastic possibilistic multiobjective programming (DSPMP) model is developed for supporting MSW management and associated GHG emission control. The DSPMP model improves upon the existing waste management optimization methods through incorporation of fuzzy possibilistic programming and chance-constrained programming into a general mixed-integer multiobjective linear programming (MOP) framework where various uncertainties expressed as fuzzy possibility distributions and probability distributions can be effectively reflected. Two conflicting objectives are integrally considered, including minimization of total system cost and minimization of total GHG emissions from waste management facilities. Three planning scenarios are analyzed and compared, representing different preferences of the decision makers for economic development and environmental-impact (i.e. GHG-emission) issues in integrated MSW management. Optimal decision schemes under three scenarios and different p(i) levels (representing the probability that the constraints would be violated) are generated for planning waste flow allocation and facility capacity expansions as well as GHG emission control. The results indicate that economic and environmental tradeoffs can be effectively reflected through the proposed DSPMP model. The generated decision variables can help the decision makers justify and/or adjust their waste management strategies based on their implicit knowledge and preferences. PMID:23313898

  9. Robust optimization of a mathematical model to design a dynamic cell formation problem considering labor utilization

    NASA Astrophysics Data System (ADS)

    Vafaeinezhad, Moghadaseh; Kia, Reza; Shahnazari-Shahrezaei, Parisa

    2015-11-01

    Cell formation (CF) problem is one of the most important decision problems in designing a cellular manufacturing system includes grouping machines into machine cells and parts into part families. Several factors should be considered in a cell formation problem. In this work, robust optimization of a mathematical model of a dynamic cell formation problem integrating CF, production planning and worker assignment is implemented with uncertain scenario-based data. The robust approach is used to reduce the effects of fluctuations of the uncertain parameters with regards to all possible future scenarios. In this research, miscellaneous cost parameters of the cell formation and demand fluctuations are subject to uncertainty and a mixed-integer nonlinear programming model is developed to formulate the related robust dynamic cell formation problem. The objective function seeks to minimize total costs including machine constant, machine procurement, machine relocation, machine operation, inter-cell and intra-cell movement, overtime, shifting labors between cells and inventory holding. Finally, a case study is carried out to display the robustness and effectiveness of the proposed model. The tradeoff between solution robustness and model robustness is also analyzed in the obtained results.

  10. Optimization using Extremal Dynamics

    NASA Astrophysics Data System (ADS)

    Boettcher, Stefan

    2001-03-01

    We explore a new heuristic for finding high-quality solutions to NP-hard optimization problems which we have recently introduced [see ``Nature's Way of Optimizing," Artificial Intelligence 119, 275-286 (2000) and cond-mat/0010337]. The method, called extremal optimization, is inspired by self-organized criticality, a concept introduced to describe emergent complexity in physical systems. Extremal optimization successively replaces extremely undesirable elements of a single sub-optimal solution with new, random ones. Large fluctuations ensue that efficiently explore many local optima. With only one adjustable parameter, its performance has proved competitive with more elaborate methods, especially near phase transitions which are believed to contain the hardest instances. In particular, extremal optimization is superior to simulated annealing in the partitioning of sparse graphs, it finds the overlap of all ground-states at the phase transition of the 3-coloring problem, and it provides independent confirmation for the ground-state energy of spin glasses, previously obtained with elaborate genetic algorithms.

  11. Adaptive critics for dynamic optimization.

    PubMed

    Kulkarni, Raghavendra V; Venayagamoorthy, Ganesh Kumar

    2010-06-01

    A novel action-dependent adaptive critic design (ACD) is developed for dynamic optimization. The proposed combination of a particle swarm optimization-based actor and a neural network critic is demonstrated through dynamic sleep scheduling of wireless sensor motes for wildlife monitoring. The objective of the sleep scheduler is to dynamically adapt the sleep duration to node's battery capacity and movement pattern of animals in its environment in order to obtain snapshots of the animal on its trajectory uniformly. Simulation results show that the sleep time of the node determined by the actor critic yields superior quality of sensory data acquisition and enhanced node longevity. PMID:20223635

  12. An inexact dynamic optimization model for municipal solid waste management in association with greenhouse gas emission control.

    PubMed

    Lu, H W; Huang, G H; He, L; Zeng, G M

    2009-01-01

    Municipal solid waste (MSW) should be properly disposed in order to help protect environmental quality and human health, as well as to preserve natural resources. During MSW disposal processes, a large amount of greenhouse gas (GHG) is emitted, leading to a significant impact on climate change. In this study, an inexact dynamic optimization model (IDOM) is developed for MSW-management systems under uncertainty. It grounds upon conventional mixed-integer linear programming (MILP) approaches, and integrates GHG components into the modeling framework. Compared with the existing models, IDOM can not only deal with the complex tradeoff between system cost minimization and GHG-emission mitigation, but also provide optimal allocation strategies under various emission-control standards. A case study is then provided for demonstrating applicability of the developed model. The results indicate that desired waste-flow patterns with a minimized system cost and GHG-emission amount can be obtained. Of more importance, the IDOM solution is associated with over 5.5 million tonnes of TEC reduction, which is of significant economic implication for real implementations. Therefore, the proposed model could be regarded as a useful tool for realizing comprehensive MSW management with regard to mitigating climate-change impacts. PMID:18096299

  13. Optimal operation of a potable water distribution network.

    PubMed

    Biscos, C; Mulholland, M; Le Lann, M V; Brouckaert, C J; Bailey, R; Roustan, M

    2002-01-01

    This paper presents an approach to an optimal operation of a potable water distribution network. The main control objective defined during the preliminary steps was to maximise the use of low-cost power, maintaining at the same time minimum emergency levels in all reservoirs. The combination of dynamic elements (e.g. reservoirs) and discrete elements (pumps, valves, routing) makes this a challenging predictive control and constrained optimisation problem, which is being solved by MINLP (Mixed Integer Non-linear Programming). Initial experimental results show the performance of this algorithm and its ability to control the water distribution process. PMID:12448464

  14. Optimal dynamic detection of explosives

    SciTech Connect

    Moore, David Steven; Mcgrane, Shawn D; Greenfield, Margo T; Scharff, R J; Rabitz, Herschel A; Roslund, J

    2009-01-01

    The detection of explosives is a notoriously difficult problem, especially at stand-off distances, due to their (generally) low vapor pressure, environmental and matrix interferences, and packaging. We are exploring optimal dynamic detection to exploit the best capabilities of recent advances in laser technology and recent discoveries in optimal shaping of laser pulses for control of molecular processes to significantly enhance the standoff detection of explosives. The core of the ODD-Ex technique is the introduction of optimally shaped laser pulses to simultaneously enhance sensitivity of explosives signatures while reducing the influence of noise and the signals from background interferents in the field (increase selectivity). These goals are being addressed by operating in an optimal nonlinear fashion, typically with a single shaped laser pulse inherently containing within it coherently locked control and probe sub-pulses. With sufficient bandwidth, the technique is capable of intrinsically providing orthogonal broad spectral information for data fusion, all from a single optimal pulse.

  15. New numerical methods for open-loop and feedback solutions to dynamic optimization problems

    NASA Astrophysics Data System (ADS)

    Ghosh, Pradipto

    The topic of the first part of this research is trajectory optimization of dynamical systems via computational swarm intelligence. Particle swarm optimization is a nature-inspired heuristic search method that relies on a group of potential solutions to explore the fitness landscape. Conceptually, each particle in the swarm uses its own memory as well as the knowledge accumulated by the entire swarm to iteratively converge on an optimal or near-optimal solution. It is relatively straightforward to implement and unlike gradient-based solvers, does not require an initial guess or continuity in the problem definition. Although particle swarm optimization has been successfully employed in solving static optimization problems, its application in dynamic optimization, as posed in optimal control theory, is still relatively new. In the first half of this thesis particle swarm optimization is used to generate near-optimal solutions to several nontrivial trajectory optimization problems including thrust programming for minimum fuel, multi-burn spacecraft orbit transfer, and computing minimum-time rest-to-rest trajectories for a robotic manipulator. A distinct feature of the particle swarm optimization implementation in this work is the runtime selection of the optimal solution structure. Optimal trajectories are generated by solving instances of constrained nonlinear mixed-integer programming problems with the swarming technique. For each solved optimal programming problem, the particle swarm optimization result is compared with a nearly exact solution found via a direct method using nonlinear programming. Numerical experiments indicate that swarm search can locate solutions to very great accuracy. The second half of this research develops a new extremal-field approach for synthesizing nearly optimal feedback controllers for optimal control and two-player pursuit-evasion games described by general nonlinear differential equations. A notable revelation from this development is that the resulting control law has an algebraic closed-form structure. The proposed method uses an optimal spatial statistical predictor called universal kriging to construct the surrogate model of a feedback controller, which is capable of quickly predicting an optimal control estimate based on current state (and time) information. With universal kriging, an approximation to the optimal feedback map is computed by conceptualizing a set of state-control samples from pre-computed extremals to be a particular realization of a jointly Gaussian spatial process. Feedback policies are computed for a variety of example dynamic optimization problems in order to evaluate the effectiveness of this methodology. This feedback synthesis approach is found to combine good numerical accuracy with low computational overhead, making it a suitable candidate for real-time applications. Particle swarm and universal kriging are combined for a capstone example, a near optimal, near-admissible, full-state feedback control law is computed and tested for the heat-load-limited atmospheric-turn guidance of an aeroassisted transfer vehicle. The performance of this explicit guidance scheme is found to be very promising; initial errors in atmospheric entry due to simulated thruster misfirings are found to be accurately corrected while closely respecting the algebraic state-inequality constraint.

  16. An optimal spacecraft scheduling model for the NASA deep space network

    NASA Technical Reports Server (NTRS)

    Webb, W. A.

    1985-01-01

    A computer model is described which uses mixed-integer linear programming to provide optimal DSN spacecraft schedules given a mission set and specified scheduling requirements. A solution technique is proposed which uses Bender's method and a heuristic starting algorithm.

  17. Final Report-Optimization Under Uncertainty and Nonconvexity: Algorithms and Software

    SciTech Connect

    Jeff Linderoth

    2008-10-10

    The goal of this research was to develop new algorithmic techniques for solving large-scale numerical optimization problems, focusing on problems classes that have proven to be among the most challenging for practitioners: those involving uncertainty and those involving nonconvexity. This research advanced the state-of-the-art in solving mixed integer linear programs containing symmetry, mixed integer nonlinear programs, and stochastic optimization problems.

  18. Multiobjective optimization of dynamic aperture

    SciTech Connect

    Yang, L.; Li, Y.; Guo, W.; Krinsky, S.

    2011-05-02

    Dynamic aperture (DA) is one of the key nonlinear properties for a storage ring. Although there have been both analytical and numerical methods to find the aperture, the reverse problem of how to optimize it is still a challenging problem. A general and flexible way of optimizing the DA is highly demanded in accelerator design and operation. In this paper, we discuss the use of multiobjective optimization for DA. First we consider using objective functions based only on numerical tracking results. Data mining of these results demonstrated a correlation between DA and low-order nonlinear driving terms. Next we considered using objective functions which included both numerical tracking results and analytical estimates of low-order nonlinear driving terms. This resulted in faster convergence. The National Synchrotron Light Source II (NSLS-II) lattice was taken as an example to illustrate this method. This multiobjective approach is not limited by particular linear or nonlinear lattice settings, and can also be applied for optimizing other properties of a storage ring.

  19. Demystifying optimal dynamic treatment regimes.

    PubMed

    Moodie, Erica E M; Richardson, Thomas S; Stephens, David A

    2007-06-01

    A dynamic regime is a function that takes treatment and covariate history and baseline covariates as inputs and returns a decision to be made. Murphy (2003, Journal of the Royal Statistical Society, Series B 65, 331-366) and Robins (2004, Proceedings of the Second Seattle Symposium on Biostatistics, 189-326) have proposed models and developed semiparametric methods for making inference about the optimal regime in a multi-interval trial that provide clear advantages over traditional parametric approaches. We show that Murphy's model is a special case of Robins's and that the methods are closely related but not equivalent. Interesting features of the methods are highlighted using the Multicenter AIDS Cohort Study and through simulation. PMID:17688497

  20. TRACKING CODE DEVELOPMENT FOR BEAM DYNAMICS OPTIMIZATION

    SciTech Connect

    Yang, L.

    2011-03-28

    Dynamic aperture (DA) optimization with direct particle tracking is a straight forward approach when the computing power is permitted. It can have various realistic errors included and is more close than theoretical estimations. In this approach, a fast and parallel tracking code could be very helpful. In this presentation, we describe an implementation of storage ring particle tracking code TESLA for beam dynamics optimization. It supports MPI based parallel computing and is robust as DA calculation engine. This code has been used in the NSLS-II dynamics optimizations and obtained promising performance.

  1. PILOT_PROTEIN: Identification of unmodified and modified proteins via high-resolution mass spectrometry and mixed-integer linear optimization

    PubMed Central

    Baliban, Richard C.; DiMaggio, Peter A.; Plazas-Mayorca, Mariana D.; Garcia, Benjamin A.; Floudas, Christodoulos A.

    2012-01-01

    A novel protein identification framework, PILOT_PROTEIN, has been developed to construct a comprehensive list of all unmodified proteins that are present in a living sample. It uses the peptide identification results from the PILOT_SEQUEL algorithm to initially determine all unmodified proteins within the sample. Using a rigorous biclustering approach that groups incorrect peptide sequences with other homologous sequences, the number of false positives reported is minimized. A sequence tag procedure is then incorporated along with the untargeted PTM identification algorithm, PILOT_PTM, to determine a list of all modification types and sites for each protein. The unmodified protein identification algorithm, PILOT_PROTEIN, is compared to the methods SEQUEST, InsPecT, X!Tandem, VEMS, and ProteinProspector using both prepared protein samples and a more complex chromatin digest. The algorithm demonstrates superior protein identification accuracy with a lower false positive rate. All materials are freely available to the scientific community at http://pumpd.princeton.edu. PMID:22788846

  2. Streak camera dynamic range optimization

    SciTech Connect

    Wiedwald, J.D.; Lerche, R.A.

    1987-09-01

    The LLNL optical streak camera is used by the Laser Fusion Program in a wide range of applications. Many of these applications require a large recorded dynamic range. Recent work has focused on maximizing the dynamic range of the streak camera recording system. For our streak cameras, image intensifier saturation limits the upper end of the dynamic range. We have developed procedures to set the image intensifier gain such that the system dynamic range is maximized. Specifically, the gain is set such that a single streak tube photoelectron is recorded with an exposure of about five times the recording system noise. This ensures detection of single photoelectrons, while not consuming intensifier or recording system dynamic range through excessive intensifier gain. The optimum intensifier gain has been determined for two types of film and for a lens-coupled CCD camera. We have determined that by recording the streak camera image with a CCD camera, the system is shot-noise limited up to the onset of image intensifier nonlinearity. When recording on film, the film determines the noise at high exposure levels. There is discussion of the effects of slit width and image intensifier saturation on dynamic range. 8 refs.

  3. Optimizing Dynamical Network Structure for Pinning Control.

    PubMed

    Orouskhani, Yasin; Jalili, Mahdi; Yu, Xinghuo

    2016-01-01

    Controlling dynamics of a network from any initial state to a final desired state has many applications in different disciplines from engineering to biology and social sciences. In this work, we optimize the network structure for pinning control. The problem is formulated as four optimization tasks: i) optimizing the locations of driver nodes, ii) optimizing the feedback gains, iii) optimizing simultaneously the locations of driver nodes and feedback gains, and iv) optimizing the connection weights. A newly developed population-based optimization technique (cat swarm optimization) is used as the optimization method. In order to verify the methods, we use both real-world networks, and model scale-free and small-world networks. Extensive simulation results show that the optimal placement of driver nodes significantly outperforms heuristic methods including placing drivers based on various centrality measures (degree, betweenness, closeness and clustering coefficient). The pinning controllability is further improved by optimizing the feedback gains. We also show that one can significantly improve the controllability by optimizing the connection weights. PMID:27067020

  4. Optimizing Dynamical Network Structure for Pinning Control

    NASA Astrophysics Data System (ADS)

    Orouskhani, Yasin; Jalili, Mahdi; Yu, Xinghuo

    2016-04-01

    Controlling dynamics of a network from any initial state to a final desired state has many applications in different disciplines from engineering to biology and social sciences. In this work, we optimize the network structure for pinning control. The problem is formulated as four optimization tasks: i) optimizing the locations of driver nodes, ii) optimizing the feedback gains, iii) optimizing simultaneously the locations of driver nodes and feedback gains, and iv) optimizing the connection weights. A newly developed population-based optimization technique (cat swarm optimization) is used as the optimization method. In order to verify the methods, we use both real-world networks, and model scale-free and small-world networks. Extensive simulation results show that the optimal placement of driver nodes significantly outperforms heuristic methods including placing drivers based on various centrality measures (degree, betweenness, closeness and clustering coefficient). The pinning controllability is further improved by optimizing the feedback gains. We also show that one can significantly improve the controllability by optimizing the connection weights.

  5. Optimizing Dynamical Network Structure for Pinning Control

    PubMed Central

    Orouskhani, Yasin; Jalili, Mahdi; Yu, Xinghuo

    2016-01-01

    Controlling dynamics of a network from any initial state to a final desired state has many applications in different disciplines from engineering to biology and social sciences. In this work, we optimize the network structure for pinning control. The problem is formulated as four optimization tasks: i) optimizing the locations of driver nodes, ii) optimizing the feedback gains, iii) optimizing simultaneously the locations of driver nodes and feedback gains, and iv) optimizing the connection weights. A newly developed population-based optimization technique (cat swarm optimization) is used as the optimization method. In order to verify the methods, we use both real-world networks, and model scale-free and small-world networks. Extensive simulation results show that the optimal placement of driver nodes significantly outperforms heuristic methods including placing drivers based on various centrality measures (degree, betweenness, closeness and clustering coefficient). The pinning controllability is further improved by optimizing the feedback gains. We also show that one can significantly improve the controllability by optimizing the connection weights. PMID:27067020

  6. Dynamic optimization and adaptive controller design

    NASA Astrophysics Data System (ADS)

    Inamdar, S. R.

    2010-10-01

    In this work I present a new type of controller which is an adaptive tracking controller which employs dynamic optimization for optimizing current value of controller action for the temperature control of nonisothermal continuously stirred tank reactor (CSTR). We begin with a two-state model of nonisothermal CSTR which are mass and heat balance equations and then add cooling system dynamics to eliminate input multiplicity. The initial design value is obtained using local stability of steady states where approach temperature for cooling action is specified as a steady state and a design specification. Later we make a correction in the dynamics where material balance is manipulated to use feed concentration as a system parameter as an adaptive control measure in order to avoid actuator saturation for the main control loop. The analysis leading to design of dynamic optimization based parameter adaptive controller is presented. The important component of this mathematical framework is reference trajectory generation to form an adaptive control measure.

  7. Efficient dynamic optimization of logic programs

    NASA Technical Reports Server (NTRS)

    Laird, Phil

    1992-01-01

    A summary is given of the dynamic optimization approach to speed up learning for logic programs. The problem is to restructure a recursive program into an equivalent program whose expected performance is optimal for an unknown but fixed population of problem instances. We define the term 'optimal' relative to the source of input instances and sketch an algorithm that can come within a logarithmic factor of optimal with high probability. Finally, we show that finding high-utility unfolding operations (such as EBG) can be reduced to clause reordering.

  8. Optimizing dissolution dynamic nuclear polarization.

    PubMed

    Bornet, Aurélien; Jannin, Sami

    2016-03-01

    This article is a short review of some of our recent developments in dissolution dynamic nuclear polarization (d-DNP). We present the basic principles of d-DNP, and motivate our choice to step away from conventional approaches. We then introduce a modified d-DNP recipe that can be summed up as follows. PMID:26920826

  9. Optimizing dissolution dynamic nuclear polarization

    NASA Astrophysics Data System (ADS)

    Bornet, Aurélien; Jannin, Sami

    2016-03-01

    This article is a short review of some of our recent developments in dissolution dynamic nuclear polarization (d-DNP). We present the basic principles of d-DNP, and motivate our choice to step away from conventional approaches. We then introduce a modified d-DNP recipe that can be summed up as follows:

  10. Dynamic programming in applied optimization problems

    NASA Astrophysics Data System (ADS)

    Zavalishchin, Dmitry

    2015-11-01

    Features of the use dynamic programming in applied problems are investigated. In practice such problems as finding the critical paths in network planning and control, finding the optimal supply plan in transportation problem, objects territorial distribution are traditionally solved by special methods of operations research. It should be noted that the dynamic programming is not provided computational advantages, but facilitates changes and modifications of tasks. This follows from the Bellman's optimality principle. The features of the multistage decision processes construction in applied problems are provided.

  11. Optimal BLS: Optimizing transit-signal detection for Keplerian dynamics

    NASA Astrophysics Data System (ADS)

    Ofir, Aviv

    2015-08-01

    Transit surveys, both ground- and space-based, have already accumulated a large number of light curves that span several years. We optimize the search for transit signals for both detection and computational efficiencies by assuming that the searched systems can be described by Keplerian, and propagating the effects of different system parameters to the detection parameters. Importnantly, we mainly consider the information content of the transit signal and not any specific algorithm - and use BLS (Kovács, Zucker, & Mazeh 2002) just as a specific example.We show that the frequency information content of the light curve is primarily determined by the duty cycle of the transit signal, and thus the optimal frequency sampling is found to be cubic and not linear. Further optimization is achieved by considering duty-cycle dependent binning of the phased light curve. By using the (standard) BLS, one is either fairly insensitive to long-period planets or less sensitive to short-period planets and computationally slower by a significant factor of ~330 (for a 3 yr long dataset). We also show how the physical system parameters, such as the host star's size and mass, directly affect transit detection. This understanding can then be used to optimize the search for every star individually.By considering Keplerian dynamics explicitly rather than implicitly one can optimally search the transit signal parameter space. The presented Optimal BLS enhances the detectability of both very short and very long period planets, while allowing such searches to be done with much reduced resources and time. The Matlab/Octave source code for Optimal BLS is made available.

  12. Estimation of Optimal Dynamic Treatment Regimes

    PubMed Central

    Laber, Eric B.

    2014-01-01

    Background Recent advances in medical research suggest that the optimal treatment rules should be adaptive to patients over time. This has led to an increasing interest in studying dynamic treatment regimes (DTRs), a sequence of individualized treatment rules, one per stage of clinical intervention, which map present patient information to a recommended treatment. There has been a recent surge of statistical work for estimating optimal DTRs from randomized and observational studies. The purpose of this paper is to review recent methodological progress and applied issues associated with estimating optimal DTRs. Methods We discuss Sequential Multiple Assignment Randomized Trials (SMARTs), a clinical trial design used to study treatment sequences. We use a common estimator of an optimal DTR that applies to SMART data as a platform to discuss several practical and methodological issues. Results We provide a limited survey of practical issues associated with modeling SMART data. We review some existing estimators of optimal dynamic treatment regimes and discuss practical issues associated with these methods including: model building; missing data; statistical inference; and choosing an outcome when only non-responders are re-randomized. We mainly focus on the estimation and inference of DTRs using SMART data. DTRs can also be constructed from observational data, which may be easier to obtain in practice, however, care must be taken to account for potential confounding. PMID:24872361

  13. Optimizing Motion Planning for Hyper Dynamic Manipulator

    NASA Astrophysics Data System (ADS)

    Aboura, Souhila; Omari, Abdelhafid; Meguenni, Kadda Zemalache

    2012-01-01

    This paper investigates the optimal motion planning for an hyper dynamic manipulator. As case study, we consider a golf swing robot which is consisting with two actuated joint and a mechanical stoppers. Genetic Algorithm (GA) technique is proposed to solve the optimal golf swing motion which is generated by Fourier series approximation. The objective function for GA approach is to minimizing the intermediate and final state, minimizing the robot's energy consummation and maximizing the robot's speed. Obtained simulation results show the effectiveness of the proposed scheme.

  14. Pareto optimization in algebraic dynamic programming.

    PubMed

    Saule, Cédric; Giegerich, Robert

    2015-01-01

    Pareto optimization combines independent objectives by computing the Pareto front of its search space, defined as the set of all solutions for which no other candidate solution scores better under all objectives. This gives, in a precise sense, better information than an artificial amalgamation of different scores into a single objective, but is more costly to compute. Pareto optimization naturally occurs with genetic algorithms, albeit in a heuristic fashion. Non-heuristic Pareto optimization so far has been used only with a few applications in bioinformatics. We study exact Pareto optimization for two objectives in a dynamic programming framework. We define a binary Pareto product operator [Formula: see text] on arbitrary scoring schemes. Independent of a particular algorithm, we prove that for two scoring schemes A and B used in dynamic programming, the scoring scheme [Formula: see text] correctly performs Pareto optimization over the same search space. We study different implementations of the Pareto operator with respect to their asymptotic and empirical efficiency. Without artificial amalgamation of objectives, and with no heuristics involved, Pareto optimization is faster than computing the same number of answers separately for each objective. For RNA structure prediction under the minimum free energy versus the maximum expected accuracy model, we show that the empirical size of the Pareto front remains within reasonable bounds. Pareto optimization lends itself to the comparative investigation of the behavior of two alternative scoring schemes for the same purpose. For the above scoring schemes, we observe that the Pareto front can be seen as a composition of a few macrostates, each consisting of several microstates that differ in the same limited way. We also study the relationship between abstract shape analysis and the Pareto front, and find that they extract information of a different nature from the folding space and can be meaningfully combined. PMID:26150892

  15. Application of optimal prediction to molecular dynamics

    SciTech Connect

    Barber IV, John Letherman

    2004-12-01

    Optimal prediction is a general system reduction technique for large sets of differential equations. In this method, which was devised by Chorin, Hald, Kast, Kupferman, and Levy, a projection operator formalism is used to construct a smaller system of equations governing the dynamics of a subset of the original degrees of freedom. This reduced system consists of an effective Hamiltonian dynamics, augmented by an integral memory term and a random noise term. Molecular dynamics is a method for simulating large systems of interacting fluid particles. In this thesis, I construct a formalism for applying optimal prediction to molecular dynamics, producing reduced systems from which the properties of the original system can be recovered. These reduced systems require significantly less computational time than the original system. I initially consider first-order optimal prediction, in which the memory and noise terms are neglected. I construct a pair approximation to the renormalized potential, and ignore three-particle and higher interactions. This produces a reduced system that correctly reproduces static properties of the original system, such as energy and pressure, at low-to-moderate densities. However, it fails to capture dynamical quantities, such as autocorrelation functions. I next derive a short-memory approximation, in which the memory term is represented as a linear frictional force with configuration-dependent coefficients. This allows the use of a Fokker-Planck equation to show that, in this regime, the noise is {delta}-correlated in time. This linear friction model reproduces not only the static properties of the original system, but also the autocorrelation functions of dynamical variables.

  16. Utilizing parallel optimization in computational fluid dynamics

    NASA Astrophysics Data System (ADS)

    Kokkolaras, Michael

    1998-12-01

    General problems of interest in computational fluid dynamics are investigated by means of optimization. Specifically, in the first part of the dissertation, a method of optimal incremental function approximation is developed for the adaptive solution of differential equations. Various concepts and ideas utilized by numerical techniques employed in computational mechanics and artificial neural networks (e.g. function approximation and error minimization, variational principles and weighted residuals, and adaptive grid optimization) are combined to formulate the proposed method. The basis functions and associated coefficients of a series expansion, representing the solution, are optimally selected by a parallel direct search technique at each step of the algorithm according to appropriate criteria; the solution is built sequentially. In this manner, the proposed method is adaptive in nature, although a grid is neither built nor adapted in the traditional sense using a-posteriori error estimates. Variational principles are utilized for the definition of the objective function to be extremized in the associated optimization problems, ensuring that the problem is well-posed. Complicated data structures and expensive remeshing algorithms and systems solvers are avoided. Computational efficiency is increased by using low-order basis functions and concurrent computing. Numerical results and convergence rates are reported for a range of steady-state problems, including linear and nonlinear differential equations associated with general boundary conditions, and illustrate the potential of the proposed method. Fluid dynamics applications are emphasized. Conclusions are drawn by discussing the method's limitations, advantages, and possible extensions. The second part of the dissertation is concerned with the optimization of the viscous-inviscid-interaction (VII) mechanism in an airfoil flow analysis code. The VII mechanism is based on the concept of a transpiration velocity boundary condition, whose convergence to steady state is accelerated. The number of variables in the associated optimization problem is reduced by means of function approximation concepts to ensure high number of parallel processors to number of necessary function evaluations ratio. Numerical results are presented for the NACA-0012 and the supercritical RAE-2822 airfoils subject to transonic flow conditions using a parallel direct search technique. They exhibit a satisfactory level of accuracy. Speed-up depends on the number of available computational units and increases for more challenging flow conditions and airfoil geometries. The enhanced code constitutes a useful tool for airfoil flow analysis and design and an acceptable alternative to computationally expensive high fidelity codes.

  17. Optimal bolt preload for dynamic loading

    NASA Astrophysics Data System (ADS)

    Duffey, T. A.

    1992-12-01

    A simple spring-mass model is developed for closure bolting systems. The model takes into account the effects of bolt prestress. An analytical solution is developed for the case of an initially peaked, exponentially decaying internal pressure pulse acting on the closure. The dependence of peak bolt stresses and deflections on bolt prestress level is investigated and an optimal prestress that minimizes peak bolt stress is found in certain cases. Vulnerability curves are developed for bolted-closure systems to provide rapid evaluation of the dynamic capacity of designs for a range in bolt prestress.

  18. Dynamic optimization theory with multiple objectives

    NASA Technical Reports Server (NTRS)

    Jones, John, Jr.

    1990-01-01

    Let V(t) be a vector-valued function for t belonging to closed interval a,b open interval, a real interval. The main purpose of this paper is to establish the existence of a closed interval alpha,beta contained in closed interval a,b for which there exists a t(sub O) belonging to closed interval alpha,beta contained in closed interval a,b such that V(t(sub O)) = 0, the zero vector. Use of such information in the dynamic optimization theory with multiple objectives present is needed. Examples of such systems will be given.

  19. Robust optimization with transiently chaotic dynamical systems

    NASA Astrophysics Data System (ADS)

    Sumi, R.; Molnár, B.; Ercsey-Ravasz, M.

    2014-05-01

    Efficiently solving hard optimization problems has been a strong motivation for progress in analog computing. In a recent study we presented a continuous-time dynamical system for solving the NP-complete Boolean satisfiability (SAT) problem, with a one-to-one correspondence between its stable attractors and the SAT solutions. While physical implementations could offer great efficiency, the transiently chaotic dynamics raises the question of operability in the presence of noise, unavoidable on analog devices. Here we show that the probability of finding solutions is robust to noise intensities well above those present on real hardware. We also developed a cellular neural network model realizable with analog circuits, which tolerates even larger noise intensities. These methods represent an opportunity for robust and efficient physical implementations.

  20. Optimal dynamic remapping of data parallel computations

    NASA Technical Reports Server (NTRS)

    Nicol, David M.; Reynolds, Paul F., Jr.

    1990-01-01

    A large class of data parallel computations is characterized by a sequence of phases, with phase changes occurring unpredictably. Dynamic remapping of the workload to processors may be required to maintain good performance. The problem considered, for which the utility of remapping and the future behavior of the workload are uncertain, arises when phases exhibit stable execution requirements during a given phase, but requirements change radically between phases. For these situations, a workload assignment generated for one phase may hinder performance during the next phase. This problem is treated formally for a probabilistic model of computation with at most two phases. The authors address the fundamental problem of balancing the expected remapping performance gain against the delay cost, and they derive the optimal remapping decision policy. The promise of the approach is shown by application to multiprocessor implementations of an adaptive gridding fluid dynamics program and to a battlefield simulation program.

  1. Optimal Empirical Prognostic Models of Climate Dynamics

    NASA Astrophysics Data System (ADS)

    Loskutov, E. M.; Mukhin, D.; Gavrilov, A.; Feigin, A. M.

    2014-12-01

    In this report the empirical methodology for prediction of climate dynamics is suggested. We construct the dynamical models of data patterns connected with climate indices, from observed spatially distributed time series. The models are based on artificial neural network (ANN) parameterization and have a form of discrete stochastic evolution operator mapping some sequence of systems state on the next one [1]. Different approaches to reconstruction of empirical basis (phase variables) for system's phase space representation, which is appropriate for forecasting the climate index of interest, are discussed in the report; for this purpose both linear and non-linear data expansions are considered. The most important point of the methodology is finding the optimal structural parameters of the model such as dimension of variable vector, i.e. number of principal components used for modeling, the time lag used for prediction, and number of neurons in ANN determining the quality of approximation. Actually, we need to solve the model selection problem, i.e. we want to obtain a model of optimal complexity in relation to analyzed time series. We use MDL approach [2] for this purpose: the model providing best data compression is chosen. The method is applied to space-distributed time-series of sea surface temperature and sea level pressure taken from IRI datasets [3]: the ability of proposed models to predict different climate indices (incl. Multivariate ENSO index, Pacific Decadal Oscillation index, North-Atlantic Oscillation index) is investigated. References:1. Molkov Ya. I., E. M. Loskutov, D. N. Mukhin, and A. M. Feigin, Random dynamical models from time series. Phys. Rev. E, 85, 036216, 2012.2. Molkov, Ya.I., D.N. Mukhin, E.M. Loskutov, A.M. Feigin, and G.A. Fidelin, Using the minimum description length principle for global reconstruction of dynamic systems from noisy time series. Phys. Rev. E, 80, 046207, 2009.3. IRI/LDEO Climate Data Library (http://iridl.ldeo.columbia.edu/)

  2. Optimally designed fields for controlling molecular dynamics

    NASA Astrophysics Data System (ADS)

    Rabitz, Herschel

    1991-10-01

    This research concerns the development of molecular control theory techniques for designing optical fields capable of manipulating molecular dynamic phenomena. Although is has been long recognized that lasers should be capable of manipulating dynamic events, many frustrating years of intuitively driven laboratory studies only serve to illustrate the point that the task is complex and defies intuition. The principal new component in the present research is the recognition that this problem falls into the category of control theory and its inherent complexities require the use of modern control theory tools largely developed in the engineering disciplines. Thus, the research has initiated a transfer of the control theory concepts to the molecular scale. Although much contained effort will be needed to fully develop these concepts, the research in this grant set forth the basic components of the theory and carried out illustrative studies involving the design of optical fields capable of controlling rotational, vibrational and electronic degrees of freedom. Optimal control within the quantum mechanical molecular realm represents a frontier area with many possible ultimate applications. At this stage, the theoretical tools need to be joined with merging laboratory optical pulse shaping capabilities to illustrate the power of the concepts.

  3. An Optimal Dynamic Threat Evaluation and Weapon Scheduling Technique

    NASA Astrophysics Data System (ADS)

    Naeem, H.; Masood, A.

    Real time scheduling problems demand high level of flexibility and robustness under complex dynamic scenarios. Threat Evaluation (TE) and Weapon Assignment (WA), together TEWA is one such complex dynamic system having optimal or near optimal utilization of scarce defensive resources of supreme priority. Several static solutions of TEWA have been proposed. This paper discusses an optimal dynamic multi-air threat evaluation and weapon allocation algorithm using a variant of Stable Marriage Algorithm (SMA). WA uses a new dynamic weapon scheduling algorithm, allowing multiple engagements using shoot-look-shoot strategy, to compute near-optimal solution. Testing part of this paper shows feasibility of this approach for a range of scenarios.

  4. Dynamic optimization of a copolymerization reactor using tabu search.

    PubMed

    Anand, P; Rao, M Bhagvanth; Venkateswarlu, Ch

    2015-03-01

    A novel multistage dynamic optimization strategy based on meta-heuristic tabu search (TS) is proposed and evaluated through sequential and simultaneous implementation procedures by applying it to a semi-batch styrene-acrylonitrile (SAN) copolymerization reactor. The adaptive memory and responsive exploration features of TS are exploited to design the dynamic optimization strategy and compute the optimal control policies for temperature and monomer addition rate so as to achieve the desired product quality parameters expressed in terms of single and multiple objectives. The dynamic optimization results of TS sequential and TS simultaneous implementation strategies are analyzed and compared with those of a conventional optimization technique based on iterative dynamic programming (IDP). The simulation results demonstrate the usefulness of TS for optimal control of transient dynamic systems. PMID:25466914

  5. Chaotic dynamics in optimal monetary policy

    NASA Astrophysics Data System (ADS)

    Gomes, O.; Mendes, V. M.; Mendes, D. A.; Sousa Ramos, J.

    2007-05-01

    There is by now a large consensus in modern monetary policy. This consensus has been built upon a dynamic general equilibrium model of optimal monetary policy as developed by, e.g., Goodfriend and King [ NBER Macroeconomics Annual 1997 edited by B. Bernanke and J. Rotemberg (Cambridge, Mass.: MIT Press, 1997), pp. 231 282], Clarida et al. [J. Econ. Lit. 37, 1661 (1999)], Svensson [J. Mon. Econ. 43, 607 (1999)] and Woodford [ Interest and Prices: Foundations of a Theory of Monetary Policy (Princeton, New Jersey, Princeton University Press, 2003)]. In this paper we extend the standard optimal monetary policy model by introducing nonlinearity into the Phillips curve. Under the specific form of nonlinearity proposed in our paper (which allows for convexity and concavity and secures closed form solutions), we show that the introduction of a nonlinear Phillips curve into the structure of the standard model in a discrete time and deterministic framework produces radical changes to the major conclusions regarding stability and the efficiency of monetary policy. We emphasize the following main results: (i) instead of a unique fixed point we end up with multiple equilibria; (ii) instead of saddle-path stability, for different sets of parameter values we may have saddle stability, totally unstable equilibria and chaotic attractors; (iii) for certain degrees of convexity and/or concavity of the Phillips curve, where endogenous fluctuations arise, one is able to encounter various results that seem intuitively correct. Firstly, when the Central Bank pays attention essentially to inflation targeting, the inflation rate has a lower mean and is less volatile; secondly, when the degree of price stickiness is high, the inflation rate displays a larger mean and higher volatility (but this is sensitive to the values given to the parameters of the model); and thirdly, the higher the target value of the output gap chosen by the Central Bank, the higher is the inflation rate and its volatility.

  6. Optimal control of HIV/AIDS dynamic: Education and treatment

    NASA Astrophysics Data System (ADS)

    Sule, Amiru; Abdullah, Farah Aini

    2014-07-01

    A mathematical model which describes the transmission dynamics of HIV/AIDS is developed. The optimal control representing education and treatment for this model is explored. The existence of optimal Control is established analytically by the use of optimal control theory. Numerical simulations suggest that education and treatment for the infected has a positive impact on HIV/AIDS control.

  7. Multi-objective optimization for deepwater dynamic umbilical installation analysis

    NASA Astrophysics Data System (ADS)

    Yang, HeZhen; Wang, AiJun; Li, HuaJun

    2012-08-01

    We suggest a method of multi-objective optimization based on approximation model for dynamic umbilical installation. The optimization aims to find out the most cost effective size, quantity and location of buoyancy modules for umbilical installation while maintaining structural safety. The approximation model is constructed by the design of experiment (DOE) sampling and is utilized to solve the problem of time-consuming analyses. The non-linear dynamic analyses considering environmental loadings are executed on these sample points from DOE. Non-dominated Sorting Genetic Algorithm (NSGA-II) is employed to obtain the Pareto solution set through an evolutionary optimization process. Intuitionist fuzzy set theory is applied for selecting the best compromise solution from Pareto set. The optimization results indicate this optimization strategy with approximation model and multiple attribute decision-making method is valid, and provide the optimal deployment method for deepwater dynamic umbilical buoyancy modules.

  8. Structural optimization with constraints from dynamics in Lagrange

    NASA Technical Reports Server (NTRS)

    Pfeiffer, F.; Kneppe, G.; Ross, C.

    1990-01-01

    Structural optimization problems are mostly solved under constraints from statics, such as stresses, strains, or displacements under static loads. But in the design process, dynamic quantities like eigenfrequencies or accelerations under dynamic loads become more and more important. Therefore, it is obvious that constraints from dynamics must be considered in structural optimization packages. This paper addresses the dynamics branch in MBB-LAGRANGE. It will concentrate on two topics, namely on the different formulations for eigenfrequency constraints and on frequency response constraints. For the latter the necessity of a system reduction is emphasized. The methods implemented in LAGRANGE are presented and examples are given.

  9. Dynamic systems of regional economy management optimization

    NASA Astrophysics Data System (ADS)

    Trofimov, S.; Kudzh, S.

    One of the most actual problems of the Russian economic life is a regional economic systems formation. The hierarchy of economic and branch priorities should follow from the general idea of an industrial policy. The matter is that the concept of an industrial policy is defined by the system of priorities mainly incorporated in it. The problem of priorities is not solved yet neither on federal, nor at a regional level. It is necessary to recognize, that a substantiation of this or that variant of priorities - objectively a challenge. Such substantiation can be received with the help of dynamic structural modeling and management technology. At formation of the regional industrial policy program the special attention is given to creation of modern type commercial structures. In regions there are headquarters and branches of many largest corporations, holdings and banks. Besides it, many regional enterprises already became inter-regional or even the transnational companies. In this connection an assistance of transformation of the industrial enterprises and their groups in vertically integrated companies and modern type holdings can become a prominent aspect of an industrial policy. Regional economic structures should be reconstructed gradually on the general model of the world class competitive companies. Assistance to creation of new corporational control systems, the organization of headquarters and the central services work - all this can be included into the sphere of regional administration industrial policy. The special attention should be turned on necessity of development of own system of the corporate structures, capable to provide to the region an independent participation in use of the natural resources and industrial-technological potential, at the stage of a regional industrial policy program formation. Transformation of the industrial enterprises and their groups into modern type vertically-integrated companies and holdings can become one of the major directions of an industrial policy of region. The situational-analytical centers (SAC) of regional administration The major component of SAC is dynamic modeling, analysis, forecasting and optimization systems, based on modern intellectual information technologies. Spheres of SAC are not only financial streams management and investments optimization, but also strategic forecasting functions, which provide an optimum choice, "aiming", search of optimum ways of regional development and corresponding investments. It is expedient to consider an opportunity of formation of the uniform organizational-methodical center of an industrial policy of region. This organization can be directly connected to the scheduled-analytical services of the largest economic structures, local authorities, the ministries and departments. Such "direct communication" is capable to provide an effective regional development strategic management. Anyway, the output on foreign markets demands concentration of resources and support of authorities. Offered measures are capable to provide a necessary coordination of efforts of a various level economic structures. For maintenance of a regional industrial policy an attraction of all newest methods of strategic planning and management is necessary. Their activity should be constructed on the basis of modern approaches of economic systems management, cause the essence of an industrial policy is finally reduced to an effective regional and corporate economic activities control centers formation. Opportunities of optimum regional economy planning and management as uniform system Approaches to planning regional economic systems can be different. We will consider some most effective methods of planning and control over a regional facilities condition. All of them are compact and evident, that allows to put them into the group of average complexity technologies. At the decision of problems of a regional resource management is rather perspective the so-called "topographical" approach, which is used by intellectual information technology "Dynamics of systems". According to it the realistic plan of regional economic system is created in the virtual space -directly on a computer desktop. And economic objects are displayed on evident schemes according to their real "geographical" structure. Each enterprise, bank, business-unit or the detached division of the company receives its own "Module" (area in working space of a spreadsheet). In result the general plan of regional economic system appears at planners. A whole real picture of all economic system functioning is recreated by such way. The idea of a method is obvious: the operator sees actual functioning of regional economy. This is promoted by "the friendly interface", allowing to display real objects as a clear symbols. The regional economy can be considered as a set of the separate enterprises connected by various economic communications. Constant monitoring of an infrastructure development, tracking of a cargoes transportation condition, supervision over following the ecological specifications by the regional enterprises, growth of housing and industrial building level, condition of communications, etc. is necessary for carrying out with the help of modern technologies of space shooting and satellite navigating systems. It will allow to obtain the data in an operative mode and will also help to the quickly modeling of a situation development variants, and to accept anticipatory administrative decisions. Other sources of the information are statistical directories and reports on a social condition in region: about a migration level and the population incomes, consumer's basket structure, demographic parameters - age of the capable population, a sexual and national attributes, etc. It is possible to attribute financial parameters to the third group: the regional budget condition data, a gain of investments into the regional economy, a growth of incomes in the regional budget from the enterprises taxes, etc. What purposes are the specified methods applied to? The regional companies management and their reforming. One of the major directions - transformation of the enterprises into the viable industrial companies, an effective economic structures formation. In this connection, the technology of financial streams management allows to solve another important problem. The created (or reorganized) structure can be checked up in various economic modes even before practical realization of the project. The received data can be applied to an indicative plans substantiation and control over their performance. They can be used at negotiations with the enterprises heads, which are spent for interests of a regional industrial policy. Such approach can become base for concrete (as figures, plans and schemes) coordination of long-term investment priorities of the largest firms and companies, their production programs coordination, the mutual markets formation and the cooperation communications stabilization, payment chains, the social and economic development programs creation. It opens opportunities for the regional branches, enterprises, the major economic centers coordinated management. An effective planning of price pools, investment programs, the control over tax revenues and financial streams becomes possible. All this are necessary elements of a regional authorities economic policy. The offered approach considerably surpasses by it's efficiency auditor, "paper" or traditional computer technology. Bulky computer centers are not capable to cope with the given class problems. At the same time the small mobile commissions of experts "armed" with modern intellectual technologies, are capable to solve rather scale analytical problems. On the basis of the offered methods can be generated means of automation of the regional industrial complex development management. They are focused on concrete objects of various scale: territorial complexes, branches, groups of the companies, the separate enterprises. Thus, the program of a regional industrial policy can be put on an effective scheduled-analytical basis.

  10. An Optimization Framework for Dynamic, Distributed Real-Time Systems

    NASA Technical Reports Server (NTRS)

    Eckert, Klaus; Juedes, David; Welch, Lonnie; Chelberg, David; Bruggerman, Carl; Drews, Frank; Fleeman, David; Parrott, David; Pfarr, Barbara

    2003-01-01

    Abstract. This paper presents a model that is useful for developing resource allocation algorithms for distributed real-time systems .that operate in dynamic environments. Interesting aspects of the model include dynamic environments, utility and service levels, which provide a means for graceful degradation in resource-constrained situations and support optimization of the allocation of resources. The paper also provides an allocation algorithm that illustrates how to use the model for producing feasible, optimal resource allocations.

  11. An Optimization Framework for Dynamic Hybrid Energy Systems

    SciTech Connect

    Wenbo Du; Humberto E Garcia; Christiaan J.J. Paredis

    2014-03-01

    A computational framework for the efficient analysis and optimization of dynamic hybrid energy systems (HES) is developed. A microgrid system with multiple inputs and multiple outputs (MIMO) is modeled using the Modelica language in the Dymola environment. The optimization loop is implemented in MATLAB, with the FMI Toolbox serving as the interface between the computational platforms. Two characteristic optimization problems are selected to demonstrate the methodology and gain insight into the system performance. The first is an unconstrained optimization problem that optimizes the dynamic properties of the battery, reactor and generator to minimize variability in the HES. The second problem takes operating and capital costs into consideration by imposing linear and nonlinear constraints on the design variables. The preliminary optimization results obtained in this study provide an essential step towards the development of a comprehensive framework for designing HES.

  12. Dynamics systems vs. optimal control--a unifying view.

    PubMed

    Schaal, Stefan; Mohajerian, Peyman; Ijspeert, Auke

    2007-01-01

    In the past, computational motor control has been approached from at least two major frameworks: the dynamic systems approach and the viewpoint of optimal control. The dynamic system approach emphasizes motor control as a process of self-organization between an animal and its environment. Nonlinear differential equations that can model entrainment and synchronization behavior are among the most favorable tools of dynamic systems modelers. In contrast, optimal control approaches view motor control as the evolutionary or development result of a nervous system that tries to optimize rather general organizational principles, e.g., energy consumption or accurate task achievement. Optimal control theory is usually employed to develop appropriate theories. Interestingly, there is rather little interaction between dynamic systems and optimal control modelers as the two approaches follow rather different philosophies and are often viewed as diametrically opposing. In this paper, we develop a computational approach to motor control that offers a unifying modeling framework for both dynamic systems and optimal control approaches. In discussions of several behavioral experiments and some theoretical and robotics studies, we demonstrate how our computational ideas allow both the representation of self-organizing processes and the optimization of movement based on reward criteria. Our modeling framework is rather simple and general, and opens opportunities to revisit many previous modeling results from this novel unifying view. PMID:17925262

  13. Parallel dynamic programming for on-line flight path optimization

    NASA Technical Reports Server (NTRS)

    Slater, G. L.; Hu, K.

    1989-01-01

    Parallel systolic algorithms for dynamic programming(DP) and their respective hardware implementations are presented for a problem in on-line trajectory optimization. The method is applied to a model for helicopter flight path optimization through a complex constraint region. This problem has application to an air traffic control problem and also to a terrain following/threat avoidance problem.

  14. Review of dynamic optimization methods in renewable natural resource management

    USGS Publications Warehouse

    Williams, B.K.

    1989-01-01

    In recent years, the applications of dynamic optimization procedures in natural resource management have proliferated. A systematic review of these applications is given in terms of a number of optimization methodologies and natural resource systems. The applicability of the methods to renewable natural resource systems are compared in terms of system complexity, system size, and precision of the optimal solutions. Recommendations are made concerning the appropriate methods for certain kinds of biological resource problems.

  15. First principles molecular dynamics without self-consistent field optimization

    SciTech Connect

    Souvatzis, Petros; Niklasson, Anders M. N.

    2014-01-28

    We present a first principles molecular dynamics approach that is based on time-reversible extended Lagrangian Born-Oppenheimer molecular dynamics [A. M. N. Niklasson, Phys. Rev. Lett. 100, 123004 (2008)] in the limit of vanishing self-consistent field optimization. The optimization-free dynamics keeps the computational cost to a minimum and typically provides molecular trajectories that closely follow the exact Born-Oppenheimer potential energy surface. Only one single diagonalization and Hamiltonian (or Fockian) construction are required in each integration time step. The proposed dynamics is derived for a general free-energy potential surface valid at finite electronic temperatures within hybrid density functional theory. Even in the event of irregular functional behavior that may cause a dynamical instability, the optimization-free limit represents a natural starting guess for force calculations that may require a more elaborate iterative electronic ground state optimization. Our optimization-free dynamics thus represents a flexible theoretical framework for a broad and general class of ab initio molecular dynamics simulations.

  16. Dynamic positioning configuration and its first-order optimization

    NASA Astrophysics Data System (ADS)

    Xue, Shuqiang; Yang, Yuanxi; Dang, Yamin; Chen, Wu

    2014-02-01

    Traditional geodetic network optimization deals with static and discrete control points. The modern space geodetic network is, on the other hand, composed of moving control points in space (satellites) and on the Earth (ground stations). The network configuration composed of these facilities is essentially dynamic and continuous. Moreover, besides the position parameter which needs to be estimated, other geophysical information or signals can also be extracted from the continuous observations. The dynamic (continuous) configuration of the space network determines whether a particular frequency of signals can be identified by this system. In this paper, we employ the functional analysis and graph theory to study the dynamic configuration of space geodetic networks, and mainly focus on the optimal estimation of the position and clock-offset parameters. The principle of the D-optimization is introduced in the Hilbert space after the concept of the traditional discrete configuration is generalized from the finite space to the infinite space. It shows that the D-optimization developed in the discrete optimization is still valid in the dynamic configuration optimization, and this is attributed to the natural generalization of least squares from the Euclidean space to the Hilbert space. Then, we introduce the principle of D-optimality invariance under the combination operation and rotation operation, and propose some D-optimal simplex dynamic configurations: (1) (Semi) circular configuration in 2-dimensional space; (2) the D-optimal cone configuration and D-optimal helical configuration which is close to the GPS constellation in 3-dimensional space. The initial design of GPS constellation can be approximately treated as a combination of 24 D-optimal helixes by properly adjusting the ascending node of different satellites to realize a so-called Walker constellation. In the case of estimating the receiver clock-offset parameter, we show that the circular configuration, the symmetrical cone configuration and helical curve configuration are still D-optimal. It shows that the given total observation time determines the optimal frequency (repeatability) of moving known points and vice versa, and one way to improve the repeatability is to increase the rotational speed. Under the Newton's law of motion, the frequency of satellite motion determines the orbital altitude. Furthermore, we study three kinds of complex dynamic configurations, one of which is the combination of D-optimal cone configurations and a so-called Walker constellation composed of D-optimal helical configuration, the other is the nested cone configuration composed of n cones, and the last is the nested helical configuration composed of n orbital planes. It shows that an effective way to achieve high coverage is to employ the configuration composed of a certain number of moving known points instead of the simplex configuration (such as D-optimal helical configuration), and one can use the D-optimal simplex solutions or D-optimal complex configurations in any combination to achieve powerful configurations with flexile coverage and flexile repeatability. Alternately, how to optimally generate and assess the discrete configurations sampled from the continuous one is discussed. The proposed configuration optimization framework has taken the well-known regular polygons (such as equilateral triangle and quadrangular) in two-dimensional space and regular polyhedrons (regular tetrahedron, cube, regular octahedron, regular icosahedron, or regular dodecahedron) into account. It shows that the conclusions made by the proposed technique are more general and no longer limited by different sampling schemes. By the conditional equation of D-optimal nested helical configuration, the relevance issues of GNSS constellation optimization are solved and some examples are performed by GPS constellation to verify the validation of the newly proposed optimization technique. The proposed technique is potentially helpful in maintenance and quadratic optimization of single GNSS of which the orbital inclination and the orbital altitude change under the precession, as well as in optimally nesting GNSSs to perform global homogeneous coverage of the Earth.

  17. Computer aided analysis and optimization of mechanical system dynamics

    NASA Technical Reports Server (NTRS)

    Haug, E. J.

    1984-01-01

    The purpose is to outline a computational approach to spatial dynamics of mechanical systems that substantially enlarges the scope of consideration to include flexible bodies, feedback control, hydraulics, and related interdisciplinary effects. Design sensitivity analysis and optimization is the ultimate goal. The approach to computer generation and solution of the system dynamic equations and graphical methods for creating animations as output is outlined.

  18. Integrated Network Decompositions and Dynamic Programming for Graph Optimization (INDDGO)

    SciTech Connect

    2012-05-31

    The INDDGO software package offers a set of tools for finding exact solutions to graph optimization problems via tree decompositions and dynamic programming algorithms. Currently the framework offers serial and parallel (distributed memory) algorithms for finding tree decompositions and solving the maximum weighted independent set problem. The parallel dynamic programming algorithm is implemented on top of the MADNESS task-based runtime.

  19. Bridging Developmental Systems Theory and Evolutionary Psychology Using Dynamic Optimization

    ERIC Educational Resources Information Center

    Frankenhuis, Willem E.; Panchanathan, Karthik; Clark Barrett, H.

    2013-01-01

    Interactions between evolutionary psychologists and developmental systems theorists have been largely antagonistic. This is unfortunate because potential synergies between the two approaches remain unexplored. This article presents a method that may help to bridge the divide, and that has proven fruitful in biology: dynamic optimization. Dynamic

  20. Neural dynamic optimization for control systems. I. Background.

    PubMed

    Seong, C Y; Widrow, B

    2001-01-01

    The paper presents neural dynamic optimization (NDO) as a method of optimal feedback control for nonlinear multi-input-multi-output (MIMO) systems. The main feature of NDO is that it enables neural networks to approximate the optimal feedback solution whose existence dynamic programming (DP) justifies, thereby reducing the complexities of computation and storage problems of the classical methods such as DP. This paper mainly describes the background and motivations for the development of NDO, while the two other subsequent papers of this topic present the theory of NDO and demonstrate the method with several applications including control of autonomous vehicles and of a robot arm, respectively. PMID:18244815

  1. Neural dynamic optimization for control systems.II. Theory.

    PubMed

    Seong, C Y; Widrow, B

    2001-01-01

    The paper presents neural dynamic optimization (NDO) as a method of optimal feedback control for nonlinear multi-input-multi-output (MIMO) systems. The main feature of NDO is that it enables neural networks to approximate the optimal feedback solution whose existence dynamic programming (DP) justifies, thereby reducing the complexities of computation and storage problems of the classical methods such as DP. This paper mainly describes the theory of NDO, while the two other companion papers of this topic explain the background for the development of NDO and demonstrate the method with several applications including control of autonomous vehicles and of a robot arm, respectively. PMID:18244816

  2. A generalized gradient algorithm for dynamic optimization

    NASA Technical Reports Server (NTRS)

    Zhao, Yiyuan; Bryson, A. E.; Slattery, R.

    1989-01-01

    A gradient algorithm is developed that determines optimal trajectories with path equality constraints and terminal constraints. A generalized gradient is formed which improves both the performance index and the path equality constraints simultaneously. The algorithm is extended to treat terminal constraints by using Bryson's impulse response technique. The main features of this algorithm are its numerical stability and smooth convergence near the optimum.

  3. Optimal entangling capacity of dynamical processes

    SciTech Connect

    Campbell, Earl T.

    2010-10-15

    We investigate the entangling capacity of dynamical operations when provided with local ancilla. A comparison is made between the entangling capacity with and without the assistance of prior entanglement. An analytic solution is found for the log-negativity entangling capacity of two-qubit gates, which equals the entanglement of the Choi matrix isomorphic to the unitary operator. Surprisingly, the availability of prior entanglement does not affect this result, a property we call resource independence of the entangling capacity. We prove several useful upper bounds on the entangling capacity that hold for general qudit dynamical operations and for a whole family of entanglement monotones including log negativity and log robustness. The log-robustness entangling capacity is shown to be resource independent for general dynamics. We provide numerical results supporting a conjecture that the log-negativity entangling capacity is resource independent for all two-qudit unitary operators.

  4. Structural optimization of rotor blades with integrated dynamics and aerodynamics

    NASA Technical Reports Server (NTRS)

    Chattopadhyay, Aditi; Walsh, Joanne L.

    1988-01-01

    The problem of structural optimization of helicopter rotor blades with integrated dynamic and aerodynamic design considerations is addressed. Results of recent optimization work on rotor blades for minimum weight with constraints on multiple coupled natural flap-lag frequencies, blade autorotational inertia and centrifugal stress has been reviewed. A strategy has been defined for the ongoing activities in the integrated dynamic/aerodynamic optimization of rotor blades. As a first step, the integrated dynamic/airload optimization problem has been formulated. To calculate system sensitivity derivatives necessary for the optimization recently developed, Global Sensitivity Equations (GSE) are being investigated. A need for multiple objective functions for the integrated optimization problem has been demonstrated and various techniques for solving the multiple objective function optimization are being investigated. The method called the Global Criteria Approach has been applied to a test problem with the blade in vacuum and the blade weight and the centrifugal stress as the multiple objectives. The results indicate that the method is quite effective in solving optimization problems with conflicting objective functions.

  5. Practical synchronization on complex dynamical networks via optimal pinning control.

    PubMed

    Li, Kezan; Sun, Weigang; Small, Michael; Fu, Xinchu

    2015-07-01

    We consider practical synchronization on complex dynamical networks under linear feedback control designed by optimal control theory. The control goal is to minimize global synchronization error and control strength over a given finite time interval, and synchronization error at terminal time. By utilizing the Pontryagin's minimum principle, and based on a general complex dynamical network, we obtain an optimal system to achieve the control goal. The result is verified by performing some numerical simulations on Star networks, Watts-Strogatz networks, and Barabási-Albert networks. Moreover, by combining optimal control and traditional pinning control, we propose an optimal pinning control strategy which depends on the network's topological structure. Obtained results show that optimal pinning control is very effective for synchronization control in real applications. PMID:26274112

  6. Practical synchronization on complex dynamical networks via optimal pinning control

    NASA Astrophysics Data System (ADS)

    Li, Kezan; Sun, Weigang; Small, Michael; Fu, Xinchu

    2015-07-01

    We consider practical synchronization on complex dynamical networks under linear feedback control designed by optimal control theory. The control goal is to minimize global synchronization error and control strength over a given finite time interval, and synchronization error at terminal time. By utilizing the Pontryagin's minimum principle, and based on a general complex dynamical network, we obtain an optimal system to achieve the control goal. The result is verified by performing some numerical simulations on Star networks, Watts-Strogatz networks, and Barabási-Albert networks. Moreover, by combining optimal control and traditional pinning control, we propose an optimal pinning control strategy which depends on the network's topological structure. Obtained results show that optimal pinning control is very effective for synchronization control in real applications.

  7. Dynamic optimization problems with bounded terminal conditions

    NASA Technical Reports Server (NTRS)

    Lee, A. Y.

    1987-01-01

    Bounded terminal conditions of nonlinear optimization problems are converted to equality terminal conditions via Valentine's device. In so doing, additional unknown parameters are introduced into the problem. The transformed problems can still be easily solved using the sequential gradient-restoration algorithm (SGRA) via a simple augmentation of the unknown parameter vector pi. Three example problems with bounded terminal conditions are solved to verify this technique.

  8. Energy-optimal path planning by stochastic dynamically orthogonal level-set optimization

    NASA Astrophysics Data System (ADS)

    Subramani, Deepak N.; Lermusiaux, Pierre F. J.

    2016-04-01

    A stochastic optimization methodology is formulated for computing energy-optimal paths from among time-optimal paths of autonomous vehicles navigating in a dynamic flow field. Based on partial differential equations, the methodology rigorously leverages the level-set equation that governs time-optimal reachability fronts for a given relative vehicle-speed function. To set up the energy optimization, the relative vehicle-speed and headings are considered to be stochastic and new stochastic Dynamically Orthogonal (DO) level-set equations are derived. Their solution provides the distribution of time-optimal reachability fronts and corresponding distribution of time-optimal paths. An optimization is then performed on the vehicle's energy-time joint distribution to select the energy-optimal paths for each arrival time, among all stochastic time-optimal paths for that arrival time. Numerical schemes to solve the reduced stochastic DO level-set equations are obtained, and accuracy and efficiency considerations are discussed. These reduced equations are first shown to be efficient at solving the governing stochastic level-sets, in part by comparisons with direct Monte Carlo simulations. To validate the methodology and illustrate its accuracy, comparisons with semi-analytical energy-optimal path solutions are then completed. In particular, we consider the energy-optimal crossing of a canonical steady front and set up its semi-analytical solution using a energy-time nested nonlinear double-optimization scheme. We then showcase the inner workings and nuances of the energy-optimal path planning, considering different mission scenarios. Finally, we study and discuss results of energy-optimal missions in a wind-driven barotropic quasi-geostrophic double-gyre ocean circulation.

  9. Combining optimal control theory and molecular dynamics for protein folding.

    PubMed

    Arkun, Yaman; Gur, Mert

    2012-01-01

    A new method to develop low-energy folding routes for proteins is presented. The novel aspect of the proposed approach is the synergistic use of optimal control theory with Molecular Dynamics (MD). In the first step of the method, optimal control theory is employed to compute the force field and the optimal folding trajectory for the Cα atoms of a Coarse-Grained (CG) protein model. The solution of this CG optimization provides an harmonic approximation of the true potential energy surface around the native state. In the next step CG optimization guides the MD simulation by specifying the optimal target positions for the Cα atoms. In turn, MD simulation provides an all-atom conformation whose Cα positions match closely the reference target positions determined by CG optimization. This is accomplished by Targeted Molecular Dynamics (TMD) which uses a bias potential or harmonic restraint in addition to the usual MD potential. Folding is a dynamical process and as such residues make different contacts during the course of folding. Therefore CG optimization has to be reinitialized and repeated over time to accomodate these important changes. At each sampled folding time, the active contacts among the residues are recalculated based on the all-atom conformation obtained from MD. Using the new set of contacts, the CG potential is updated and the CG optimal trajectory for the Cα atoms is recomputed. This is followed by MD. Implementation of this repetitive CG optimization-MD simulation cycle generates the folding trajectory. Simulations on a model protein Villin demonstrate the utility of the method. Since the method is founded on the general tools of optimal control theory and MD without any restrictions, it is widely applicable to other systems. It can be easily implemented with available MD software packages. PMID:22238629

  10. Combining Optimal Control Theory and Molecular Dynamics for Protein Folding

    PubMed Central

    Arkun, Yaman; Gur, Mert

    2012-01-01

    A new method to develop low-energy folding routes for proteins is presented. The novel aspect of the proposed approach is the synergistic use of optimal control theory with Molecular Dynamics (MD). In the first step of the method, optimal control theory is employed to compute the force field and the optimal folding trajectory for the atoms of a Coarse-Grained (CG) protein model. The solution of this CG optimization provides an harmonic approximation of the true potential energy surface around the native state. In the next step CG optimization guides the MD simulation by specifying the optimal target positions for the atoms. In turn, MD simulation provides an all-atom conformation whose positions match closely the reference target positions determined by CG optimization. This is accomplished by Targeted Molecular Dynamics (TMD) which uses a bias potential or harmonic restraint in addition to the usual MD potential. Folding is a dynamical process and as such residues make different contacts during the course of folding. Therefore CG optimization has to be reinitialized and repeated over time to accomodate these important changes. At each sampled folding time, the active contacts among the residues are recalculated based on the all-atom conformation obtained from MD. Using the new set of contacts, the CG potential is updated and the CG optimal trajectory for the atoms is recomputed. This is followed by MD. Implementation of this repetitive CG optimization - MD simulation cycle generates the folding trajectory. Simulations on a model protein Villin demonstrate the utility of the method. Since the method is founded on the general tools of optimal control theory and MD without any restrictions, it is widely applicable to other systems. It can be easily implemented with available MD software packages. PMID:22238629

  11. Dynamical optimization theory of a diversified portfolio

    NASA Astrophysics Data System (ADS)

    Marsili, Matteo; Maslov, Sergei; Zhang, Yi-Cheng

    We propose and study a simple model of dynamical redistribution of capital in a diversified portfolio. We consider a hypothetical situation of a portfolio composed of N uncorrelated stocks. Each stock price follows a multiplicative random walk with identical drift and dispersion. The rules of our model naturally give rise to power law tails in the distribution of capital fractions invested in different stocks. The exponent of this scale free distribution is calculated in both discrete and continuous time formalism. It is demonstrated that the dynamical redistribution strategy results in a larger typical growth rate of the capital than a static “buy-and-hold” strategy. In the large N limit the typical growth rate is shown to asymptotically approach that of the expectation value of the stock price. The finite dimensional variant of the model is shown to describe the partition function of directed polymers in random media.

  12. Optimal dynamic remapping of parallel computations

    NASA Technical Reports Server (NTRS)

    Nicol, David M.; Reynolds, Paul F., Jr.

    1987-01-01

    A large class of computations are characterized by a sequence of phases, with phase changes occurring unpredictably. The decision problem was considered regarding the remapping of workload to processors in a parallel computation when the utility of remapping and the future behavior of the workload is uncertain, and phases exhibit stable execution requirements during a given phase, but requirements may change radically between phases. For these problems a workload assignment generated for one phase may hinder performance during the next phase. This problem is treated formally for a probabilistic model of computation with at most two phases. The fundamental problem of balancing the expected remapping performance gain against the delay cost was addressed. Stochastic dynamic programming is used to show that the remapping decision policy minimizing the expected running time of the computation has an extremely simple structure. Because the gain may not be predictable, the performance of a heuristic policy that does not require estimnation of the gain is examined. The heuristic method's feasibility is demonstrated by its use on an adaptive fluid dynamics code on a multiprocessor. The results suggest that except in extreme cases, the remapping decision problem is essentially that of dynamically determining whether gain can be achieved by remapping after a phase change. The results also suggest that this heuristic is applicable to computations with more than two phases.

  13. Dynamic optimization of district energy grid

    NASA Astrophysics Data System (ADS)

    Salsbery, Scott

    The University of Iowa Power Plant operates utility generation and distribution for campus facilities, including electricity, steam, and chilled water. It is desirable to evaluate the optimal load combination of boilers, engines and chillers to meet the demand at minimal cost, particularly for future demand scenarios. An algorithm has been developed which takes into account the performance of individual units as part of the mix which ultimately supplies the campus and determine the degree that each should be operating to most efficiently meet demand. The algorithm is part of an integrated simulation tool which is specifically designed to apply traditional optimization techniques for a given (both current and possible) circumstance. The second component is to couple the algorithm with accurate estimates and historical data through which expected demand could be predicted. The simulation tool can account for any theoretical circumstance, which will be highly beneficial for strategic planning. As part of the process it is also necessary to determine the unique operating characteristics of the system components. The algorithms rely upon performance curves of individual system components (boiler, chiller, etc.) and those must be developed and refined when possible from experimental testing and commissioning or manufacturer supplied data.

  14. Optimal motor control may mask sensory dynamics

    PubMed Central

    Kiemel, Tim; Cowan, Noah J.; Jeka, John J.

    2009-01-01

    Properties of neural controllers for closed-loop sensorimotor behavior can be inferred with system identification. Under the standard paradigm, the closed-loop system is perturbed (input), measurements are taken (output), and the relationship between input and output reveals features of the system under study. Here we show that under common assumptions made about such systems (e.g. the system implements optimal control with a penalty on mechanical, but not sensory, states) important aspects of the neural controller (its zeros mask the modes of the sensors) remain hidden from standard system identification techniques. Only by perturbing or measuring the closed-loop system “between” the sensor and the control can these features be exposed with closed-loop system identification methods; while uncommon, there exist noninvasive techniques such as galvanic vestibular stimulation that perturb between sensor and controller in this way. PMID:19408009

  15. Synthesis of standing-up trajectories using dynamic optimization.

    PubMed

    Kuzelicki, Jernej; Zefran, Milos; Burger, Helena; Bajd, Tadej

    2005-01-01

    Dynamic optimization as a tool to compute standing-up trajectories was investigated. Sit-to-stand manoeuvres in five intact persons and five trans-femoral amputees were measured. Movements and ground reaction forces acting on the body were recorded. A five-segment 3D dynamic model of standing-up was developed. In each particular subject, the optimization criterion which yielded trajectories that best resemble the measured standing-up movement was determined. Since the intact persons used considerably different criteria in choosing the standing-up trajectories than the amputees, the optimal trajectories were computed by minimizing cost functionals (CF) with distinctive structures for each group of individuals. In intact persons, a unique cost functional was found which yielded realistic standing-up manoeuvres. In amputees, subject-specific sets of parameters indicating slightly different preferences in optimizing the effort of particular muscle groups were used. PMID:15536029

  16. Global dynamic optimization approach to predict activation in metabolic pathways

    PubMed Central

    2014-01-01

    Background During the last decade, a number of authors have shown that the genetic regulation of metabolic networks may follow optimality principles. Optimal control theory has been succesfully used to compute optimal enzyme profiles considering simple metabolic pathways. However, applying this optimal control framework to more general networks (e.g. branched networks, or networks incorporating enzyme production dynamics) yields problems that are analytically intractable and/or numerically very challenging. Further, these previous studies have only considered a single-objective framework. Results In this work we consider a more general multi-objective formulation and we present solutions based on recent developments in global dynamic optimization techniques. We illustrate the performance and capabilities of these techniques considering two sets of problems. First, we consider a set of single-objective examples of increasing complexity taken from the recent literature. We analyze the multimodal character of the associated non linear optimization problems, and we also evaluate different global optimization approaches in terms of numerical robustness, efficiency and scalability. Second, we consider generalized multi-objective formulations for several examples, and we show how this framework results in more biologically meaningful results. Conclusions The proposed strategy was used to solve a set of single-objective case studies related to unbranched and branched metabolic networks of different levels of complexity. All problems were successfully solved in reasonable computation times with our global dynamic optimization approach, reaching solutions which were comparable or better than those reported in previous literature. Further, we considered, for the first time, multi-objective formulations, illustrating how activation in metabolic pathways can be explained in terms of the best trade-offs between conflicting objectives. This new methodology can be applied to metabolic networks with arbitrary topologies, non-linear dynamics and constraints. PMID:24393148

  17. Experimental Testing of Dynamically Optimized Photoelectron Beams

    NASA Astrophysics Data System (ADS)

    Rosenzweig, J. B.; Cook, A. M.; Dunning, M.; England, R. J.; Musumeci, P.; Bellaveglia, M.; Boscolo, M.; Catani, L.; Cianchi, A.; Di Pirro, G.; Ferrario, M.; Fillipetto, D.; Gatti, G.; Palumbo, L.; Serafini, L.; Vicario, C.; Jones, S.

    2006-11-01

    We discuss the design of and initial results from an experiment in space-charge dominated beam dynamics which explores a new regime of high-brightness electron beam generation at the SPARC photoinjector. The scheme under study employs the tendency of intense electron beams to rearrange to produce uniform density, giving a nearly ideal beam from the viewpoint of space charge-induced emittance. The experiments are aimed at testing the marriage of this idea with a related concept, emittance compensation. We show that this new regime of operating photoinjector may be the preferred method of obtaining highest brightness beams with lower energy spread. We discuss the design of the experiment, including developing of a novel time-dependent, aerogel-based imaging system. This system has been installed at SPARC, and first evidence for nearly uniformly filled ellipsoidal charge distributions recorded.

  18. Optimal dynamic bandwidth allocation for complex networks

    NASA Astrophysics Data System (ADS)

    Jiang, Zhong-Yuan; Liang, Man-Gui; Li, Qian; Guo, Dong-Chao

    2013-03-01

    Traffic capacity of one network strongly depends on the link’s bandwidth allocation strategy. In previous bandwidth allocation mechanisms, once one link’s bandwidth is allocated, it will be fixed throughout the overall traffic transmission process. However, the traffic load of every link changes from time to time. In this paper, with finite total bandwidth resource of the network, we propose to dynamically allocate the total bandwidth resource in which each link’s bandwidth is proportional to the queue length of the output buffer of the link per time step. With plenty of data packets in the network, the traffic handling ability of all links of the network achieves full utilization. The theoretical analysis and the extensive simulation results on complex networks are consistent. This work is valuable for network service providers to improve network performance or to do reasonable network design efficiently.

  19. Experimental Testing of Dynamically Optimized Photoelectron Beams

    SciTech Connect

    Rosenzweig, J. B.; Cook, A. M.; Dunning, M.; England, R. J.; Musumeci, P.; Bellaveglia, M.; Boscolo, M.; Catani, L.; Cianchi, A.; Di Pirro, G.; Ferrario, M.; Fillipetto, D.; Gatti, G.; Palumbo, L.; Vicario, C.; Serafini, L.; Jones, S.

    2006-11-27

    We discuss the design of and initial results from an experiment in space-charge dominated beam dynamics which explores a new regime of high-brightness electron beam generation at the SPARC photoinjector. The scheme under study employs the tendency of intense electron beams to rearrange to produce uniform density, giving a nearly ideal beam from the viewpoint of space charge-induced emittance. The experiments are aimed at testing the marriage of this idea with a related concept, emittance compensation. We show that this new regime of operating photoinjector may be the preferred method of obtaining highest brightness beams with lower energy spread. We discuss the design of the experiment, including developing of a novel time-dependent, aerogel-based imaging system. This system has been installed at SPARC, and first evidence for nearly uniformly filled ellipsoidal charge distributions recorded.

  20. Aerospace applications on integer and combinatorial optimization

    NASA Technical Reports Server (NTRS)

    Padula, S. L.; Kincaid, R. K.

    1995-01-01

    Research supported by NASA Langley Research Center includes many applications of aerospace design optimization and is conducted by teams of applied mathematicians and aerospace engineers. This paper investigates the benefits from this combined expertise in formulating and solving integer and combinatorial optimization problems. Applications range from the design of large space antennas to interior noise control. A typical problem. for example, seeks the optimal locations for vibration-damping devices on an orbiting platform and is expressed as a mixed/integer linear programming problem with more than 1500 design variables.

  1. Aerospace applications of integer and combinatorial optimization

    NASA Technical Reports Server (NTRS)

    Padula, S. L.; Kincaid, R. K.

    1995-01-01

    Research supported by NASA Langley Research Center includes many applications of aerospace design optimization and is conducted by teams of applied mathematicians and aerospace engineers. This paper investigates the benefits from this combined expertise in solving combinatorial optimization problems. Applications range from the design of large space antennas to interior noise control. A typical problem, for example, seeks the optimal locations for vibration-damping devices on a large space structure and is expressed as a mixed/integer linear programming problem with more than 1500 design variables.

  2. Aerospace Applications of Integer and Combinatorial Optimization

    NASA Technical Reports Server (NTRS)

    Padula, S. L.; Kincaid, R. K.

    1995-01-01

    Research supported by NASA Langley Research Center includes many applications of aerospace design optimization and is conducted by teams of applied mathematicians and aerospace engineers. This paper investigates the benefits from this combined expertise in formulating and solving integer and combinatorial optimization problems. Applications range from the design of large space antennas to interior noise control. A typical problem, for example, seeks the optimal locations for vibration-damping devices on an orbiting platform and is expressed as a mixed/integer linear programming problem with more than 1500 design variables.

  3. MULTIOBJECTIVE DYNAMIC APERTURE OPTIMIZATION AT NSLS-II

    SciTech Connect

    Yang, L.; Li, Y.; Guo, W.; Krinsky, S.

    2011-03-28

    In this paper we present a multiobjective approach to the dynamic aperture (DA) optimization. Taking the NSLS-II lattice as an example, we have used both sextupoles and quadrupoles as tuning variables to optimize both on-momentum and off-momentum DA. The geometric and chromatic sextupoles are used for nonlinear properties while the tunes are independently varied by quadrupoles. The dispersion and emittance are fixed during tunes variation. The algorithms, procedures, performances and results of our optimization of DA will be discussed and they are found to be robust, general and easy to apply to similar problems.

  4. Dynamics and optimal number of replicas in parallel tempering simulations

    NASA Astrophysics Data System (ADS)

    Nadler, Walter; Hansmann, Ulrich H. E.

    2007-12-01

    We study the dynamics of parallel tempering simulations, also known as the replica exchange technique, which has become the method of choice for simulation of proteins and other complex systems. Recent results for the optimal choice of the control parameter discretization allow a treatment independent of the system in question. By analyzing mean first passage times across the control parameter space, we find an expression for the optimal number of replicas in simulations covering a given temperature range. Our results suggest a particular protocol to optimize the number of replicas in actual simulations.

  5. Dynamically optimal strategies for managing resistance to genetically modified crops.

    PubMed

    Qiao, Fangbin; Wilen, James; Rozelle, Scott

    2008-06-01

    This paper develops a dynamic model of the evolution of pest a population and pest resistance to characterize the socially optimal refuge strategy for managing a pest's resistance to genetically modified crops. Previous theoretical economic analyses of this problem focus on steady states; we also address refuge policies along the optimal path to the final equilibrium. To elaborate on our theoretical analysis of the resistance problem, we develop a simulation model calibrated to cotton (Gossypium spp.) production in China. Our results show the importance of fitness cost as a determinant of the qualitative nature of optimal refuge policies. PMID:18613595

  6. Developing learning algorithms via optimized discretization of continuous dynamical systems.

    PubMed

    Tao, Qing; Sun, Zhengya; Kong, Kang

    2012-02-01

    Most of the existing numerical optimization methods are based upon a discretization of some ordinary differential equations. In order to solve some convex and smooth optimization problems coming from machine learning, in this paper, we develop efficient batch and online algorithms based on a new principle, i.e., the optimized discretization of continuous dynamical systems (ODCDSs). First, a batch learning projected gradient dynamical system with Lyapunov's stability and monotonic property is introduced, and its dynamical behavior guarantees the accuracy of discretization-based optimizer and applicability of line search strategy. Furthermore, under fair assumptions, a new online learning algorithm achieving regret O(?T) or O(logT) is obtained. By using the line search strategy, the proposed batch learning ODCDS exhibits insensitivity to the step sizes and faster decrease. With only a small number of line search steps, the proposed stochastic algorithm shows sufficient stability and approximate optimality. Experimental results demonstrate the correctness of our theoretical analysis and efficiency of our algorithms. PMID:21880573

  7. Bridging Developmental Systems Theory and Evolutionary Psychology Using Dynamic Optimization

    ERIC Educational Resources Information Center

    Frankenhuis, Willem E.; Panchanathan, Karthik; Clark Barrett, H.

    2013-01-01

    Interactions between evolutionary psychologists and developmental systems theorists have been largely antagonistic. This is unfortunate because potential synergies between the two approaches remain unexplored. This article presents a method that may help to bridge the divide, and that has proven fruitful in biology: dynamic optimization. Dynamic…

  8. Aerodynamic design optimization with sensitivity analysis and computational fluid dynamics

    NASA Technical Reports Server (NTRS)

    Baysal, Oktay

    1995-01-01

    An investigation was conducted from October 1, 1990 to May 31, 1994 on the development of methodologies to improve the designs (more specifically, the shape) of aerodynamic surfaces of coupling optimization algorithms (OA) with Computational Fluid Dynamics (CFD) algorithms via sensitivity analyses (SA). The study produced several promising methodologies and their proof-of-concept cases, which have been reported in the open literature.

  9. Multiobjective Optimization of Low-Energy Trajectories Using Optimal Control on Dynamical Channels

    NASA Technical Reports Server (NTRS)

    Coffee, Thomas M.; Anderson, Rodney L.; Lo, Martin W.

    2011-01-01

    We introduce a computational method to design efficient low-energy trajectories by extracting initial solutions from dynamical channels formed by invariant manifolds, and improving these solutions through variational optimal control. We consider trajectories connecting two unstable periodic orbits in the circular restricted 3-body problem (CR3BP). Our method leverages dynamical channels to generate a range of solutions, and approximates the areto front for impulse and time of flight through a multiobjective optimization of these solutions based on primer vector theory. We demonstrate the application of our method to a libration orbit transfer in the Earth-Moon system.

  10. A dynamic optimization model for solid waste recycling.

    PubMed

    Anghinolfi, Davide; Paolucci, Massimo; Robba, Michela; Taramasso, Angela Celeste

    2013-02-01

    Recycling is an important part of waste management (that includes different kinds of issues: environmental, technological, economic, legislative, social, etc.). Differently from many works in literature, this paper is focused on recycling management and on the dynamic optimization of materials collection. The developed dynamic decision model is characterized by state variables, corresponding to the quantity of waste in each bin per each day, and control variables determining the quantity of material that is collected in the area each day and the routes for collecting vehicles. The objective function minimizes the sum of costs minus benefits. The developed decision model is integrated in a GIS-based Decision Support System (DSS). A case study related to the Cogoleto municipality is presented to show the effectiveness of the proposed model. From optimal results, it has been found that the net benefits of the optimized collection are about 2.5 times greater than the estimated current policy. PMID:23158873

  11. Neural dynamic optimization for control systems.III. Applications.

    PubMed

    Seong, C Y; Widrow, B

    2001-01-01

    For pt.II. see ibid., p. 490-501. The paper presents neural dynamic optimization (NDO) as a method of optimal feedback control for nonlinear multi-input-multi-output (MIMO) systems. The main feature of NDO is that it enables neural networks to approximate the optimal feedback solution whose existence dynamic programming (DP) justifies, thereby reducing the complexities of computation and storage problems of the classical methods such as DP. This paper demonstrates NDO with several applications including control of autonomous vehicles and of a robot-arm, while the two other companion papers of this topic describes the background for the development of NDO and present the theory of the method, respectively. PMID:18244817

  12. Analysis and Optimization of Pulse Dynamics for Magnetic Stimulation

    PubMed Central

    Goetz, Stefan M.; Truong, Cong Nam; Gerhofer, Manuel G.; Peterchev, Angel V.; Herzog, Hans-Georg; Weyh, Thomas

    2013-01-01

    Magnetic stimulation is a standard tool in brain research and has found important clinical applications in neurology, psychiatry, and rehabilitation. Whereas coil designs and the spatial field properties have been intensively studied in the literature, the temporal dynamics of the field has received less attention. Typically, the magnetic field waveform is determined by available device circuit topologies rather than by consideration of what is optimal for neural stimulation. This paper analyzes and optimizes the waveform dynamics using a nonlinear model of a mammalian axon. The optimization objective was to minimize the pulse energy loss. The energy loss drives power consumption and heating, which are the dominating limitations of magnetic stimulation. The optimization approach is based on a hybrid global-local method. Different coordinate systems for describing the continuous waveforms in a limited parameter space are defined for numerical stability. The optimization results suggest that there are waveforms with substantially higher efficiency than that of traditional pulse shapes. One class of optimal pulses is analyzed further. Although the coil voltage profile of these waveforms is almost rectangular, the corresponding current shape presents distinctive characteristics, such as a slow low-amplitude first phase which precedes the main pulse and reduces the losses. Representatives of this class of waveforms corresponding to different maximum voltages are linked by a nonlinear transformation. The main phase, however, scales with time only. As with conventional magnetic stimulation pulses, briefer pulses result in lower energy loss but require higher coil voltage than longer pulses. PMID:23469168

  13. Dynamic characterization of bolted joints using FRF decoupling and optimization

    NASA Astrophysics Data System (ADS)

    Tol, ?erife; Ozguven, H. Nevzat

    2015-03-01

    Mechanical connections play a significant role in predicting dynamic characteristics of assembled structures. Therefore, equivalent dynamic models for joints are needed. Due to the complexity of joints, it is difficult to describe joint dynamics with analytical models. Reliable models are generally obtained using experimental measurements. In this paper an experimental identification method based on FRF decoupling and optimization algorithm is proposed for modeling joints. In the method the FRFs of two substructures connected with a joint are measured, while the FRFs of the substructures are obtained numerically or experimentally. Then the joint properties are calculated in terms of translational, rotational and cross-coupling stiffness and damping values by using FRF decoupling. In order to eliminate the numerical errors associated with matrix inversion an optimization algorithm is used to update the joint values obtained from FRF decoupling. The validity of the proposed method is demonstrated with experimental studies with bolted joints.

  14. Optimal experimental dynamical decoupling of both longitudinal and transverse relaxations

    NASA Astrophysics Data System (ADS)

    Zhen, Xing-Long; Zhang, Fei-Hao; Feng, Guanru; Li, Hang; Long, Gui-Lu

    2016-02-01

    Both longitudinal and transverse relaxations exist in the practical environment. Their simultaneous eliminations are extremely demanding in real applications. Previous experimental work has focused mainly on the suppression of transverse relaxation. In this paper we investigate the performance of three important dynamical decoupling schemes—quadratic dynamical decoupling, periodic dynamical decoupling, and concatenated dynamical decoupling—in an environment with hybrid errors. We propose a method to engineer arbitrary environment by modulating the control field. The technique developed here is universal and can be applied to other quantum information processing systems. Three-dimensional filter functions technique is utilized to analyze the fidelity decay of a one-qubit state protected by dynamical decoupling sequences. This enables us to quantitatively compare the performance of different dynamical decoupling sequences and demonstrate the superiority of quadratic dynamical decoupling in experiments for the first time. Our work reveals that quadratic dynamical decoupling is optimal conditioned on the appropriate noise properties. The difference of constructing dynamical decoupling sequences with various Pauli pulses is also investigated.

  15. Optimizing legacy molecular dynamics software with directive-based offload

    NASA Astrophysics Data System (ADS)

    Michael Brown, W.; Carrillo, Jan-Michael Y.; Gavhane, Nitin; Thakkar, Foram M.; Plimpton, Steven J.

    2015-10-01

    Directive-based programming models are one solution for exploiting many-core coprocessors to increase simulation rates in molecular dynamics. They offer the potential to reduce code complexity with offload models that can selectively target computations to run on the CPU, the coprocessor, or both. In this paper, we describe modifications to the LAMMPS molecular dynamics code to enable concurrent calculations on a CPU and coprocessor. We demonstrate that standard molecular dynamics algorithms can run efficiently on both the CPU and an x86-based coprocessor using the same subroutines. As a consequence, we demonstrate that code optimizations for the coprocessor also result in speedups on the CPU; in extreme cases up to 4.7X. We provide results for LAMMPS benchmarks and for production molecular dynamics simulations using the Stampede hybrid supercomputer with both Intel®  Xeon Phi™ coprocessors and NVIDIA GPUs. The optimizations presented have increased simulation rates by over 2X for organic molecules and over 7X for liquid crystals on Stampede. The optimizations are available as part of the "Intel package" supplied with LAMMPS.

  16. Optimal scales to observe habitat dynamics: a coral reef example.

    PubMed

    Habeeb, Rebecca L; Johnson, Craig R; Wotherspoon, Simon; Mumby, Peter J

    2007-04-01

    A new technique to estimate the characteristic length scales (CLSs) of real ecological systems provides an objective means to identify the optimal scale(s) of observation to best detect underlying dynamical trends. Application of the technique to natural systems has focused on identifying appropriate scales to measure the dynamics of species as descriptors of community and ecosystem dynamics. However, ecosystem monitoring is often based not on assessing single species, but on species assemblages, functional groups, or habitat types. We asked whether the concept of CLSs based on dynamic interactions among species could be extended to examine interactions among habitat types and thus to identify optimal scales for observing habitat dynamics. A time series of three spatial maps of benthic habitats on a Caribbean coral reef was constructed from aerial photographs, Compact Airborne Spectrographic Imager (CASI) images, and IKONOS satellite images, providing the short time sequence required for this technique. We estimated the CLS based on the dynamics of three distinct habitat types: dense stands of seagrass, sparse stands of seagrass, and Montastrea patch reefs. Despite notable differences in the areal extent of and relative change in these habitats over the 21-year observation period, analyses based on each habitat type indicated a similar CLS of -300 m. We interpret the consistency of CLSs among habitats to indicate that the dynamics of the three habitat types are linked. The results are encouraging, and they indicate that CLS techniques can be used to identify the appropriate scale at which to monitor ecosystem trends on the basis of the dynamics of only one of a disparate suite of habitat types. PMID:17494384

  17. Set-valued dynamic treatment regimes for competing outcomes

    PubMed Central

    Laber, Eric B.; Lizotte, Daniel J.; Ferguson, Bradley

    2014-01-01

    Summary Dynamic treatment regimes operationalize the clinical decision process as a sequence of functions, one for each clinical decision, where each function maps up-to-date patient information to a single recommended treatment. Current methods for estimating optimal dynamic treatment regimes, for example Q-learning, require the specification of a single outcome by which the ‘goodness’ of competing dynamic treatment regimes is measured. However, this is an over-simplification of the goal of clinical decision making, which aims to balance several potentially competing outcomes, e.g., symptom relief and side-effect burden. When there are competing outcomes and patients do not know or cannot communicate their preferences, formation of a single composite outcome that correctly balances the competing outcomes is not possible. This problem also occurs when patient preferences evolve over time. We propose a method for constructing dynamic treatment regimes that accommodates competing outcomes by recommending sets of treatments at each decision point. Formally, we construct a sequence of set-valued functions that take as input up-to-date patient information and give as output a recommended subset of the possible treatments. For a given patient history, the recommended set of treatments contains all treatments that produce non-inferior outcome vectors. Constructing these set-valued functions requires solving a non-trivial enumeration problem. We offer an exact enumeration algorithm by recasting the problem as a linear mixed integer program. The proposed methods are illustrated using data from the CATIE schizophrenia study. PMID:24400912

  18. Power distribution system planning with reliability modeling and optimization

    SciTech Connect

    Tang, Y.

    1996-02-01

    A new approach for the systemized optimization of power distribution systems is presented in this paper. Distribution system reliability is modeled in the optimization objective function via outage costs and costs of switching devices, along with the nonlinear costs of investment, maintenance and energy losses of both the substations and the feeders. The optimization model established is multi-stage, mixed-integer and nonlinear, which is solved by a network-flow programming algorithm. A multi-stage interlacing strategy and a nonlinearity iteration method are also designed. Supported by an extensive database, the planning software tool has been applied to optimize the power distribution system of a developing city.

  19. Optimization Research of Generation Investment Based on Linear Programming Model

    NASA Astrophysics Data System (ADS)

    Wu, Juan; Ge, Xueqian

    Linear programming is an important branch of operational research and it is a mathematical method to assist the people to carry out scientific management. GAMS is an advanced simulation and optimization modeling language and it will combine a large number of complex mathematical programming, such as linear programming LP, nonlinear programming NLP, MIP and other mixed-integer programming with the system simulation. In this paper, based on the linear programming model, the optimized investment decision-making of generation is simulated and analyzed. At last, the optimal installed capacity of power plants and the final total cost are got, which provides the rational decision-making basis for optimized investments.

  20. Artificial bee colony algorithm for constrained possibilistic portfolio optimization problem

    NASA Astrophysics Data System (ADS)

    Chen, Wei

    2015-07-01

    In this paper, we discuss the portfolio optimization problem with real-world constraints under the assumption that the returns of risky assets are fuzzy numbers. A new possibilistic mean-semiabsolute deviation model is proposed, in which transaction costs, cardinality and quantity constraints are considered. Due to such constraints the proposed model becomes a mixed integer nonlinear programming problem and traditional optimization methods fail to find the optimal solution efficiently. Thus, a modified artificial bee colony (MABC) algorithm is developed to solve the corresponding optimization problem. Finally, a numerical example is given to illustrate the effectiveness of the proposed model and the corresponding algorithm.

  1. Sequential activation of metabolic pathways: a dynamic optimization approach.

    PubMed

    Oyarzún, Diego A; Ingalls, Brian P; Middleton, Richard H; Kalamatianos, Dimitrios

    2009-11-01

    The regulation of cellular metabolism facilitates robust cellular operation in the face of changing external conditions. The cellular response to this varying environment may include the activation or inactivation of appropriate metabolic pathways. Experimental and numerical observations of sequential timing in pathway activation have been reported in the literature. It has been argued that such patterns can be rationalized by means of an underlying optimal metabolic design. In this paper we pose a dynamic optimization problem that accounts for time-resource minimization in pathway activation under constrained total enzyme abundance. The optimized variables are time-dependent enzyme concentrations that drive the pathway to a steady state characterized by a prescribed metabolic flux. The problem formulation addresses unbranched pathways with irreversible kinetics. Neither specific reaction kinetics nor fixed pathway length are assumed.In the optimal solution, each enzyme follows a switching profile between zero and maximum concentration, following a temporal sequence that matches the pathway topology. This result provides an analytic justification of the sequential activation previously described in the literature. In contrast with the existent numerical approaches, the activation sequence is proven to be optimal for a generic class of monomolecular kinetics. This class includes, but is not limited to, Mass Action, Michaelis-Menten, Hill, and some Power-law models. This suggests that sequential enzyme expression may be a common feature of metabolic regulation, as it is a robust property of optimal pathway activation. PMID:19412635

  2. Shape Optimization of Vehicle Radiator Using Computational Fluid Dynamics (cfd)

    NASA Astrophysics Data System (ADS)

    Maddipatla, Sridhar; Guessous, Laila

    2002-11-01

    Automotive manufacturers need to improve the efficiency and lifetime of all engine components. In the case of radiators, performance depends significantly on coolant flow homogeneity across the tubes and overall pressure drop between the inlet and outlet. Design improvements are especially needed in tube-flow uniformity to prevent premature fouling and failure of heat exchangers. Rather than relying on ad-hoc geometry changes, the current study combines Computational Fluid Dynamics with shape optimization methods to improve radiator performance. The goal is to develop an automated suite of virtual tools to assist in radiator design. Two objective functions are considered: a flow non-uniformity coefficient,Cf, and the overall pressure drop, dP*. The methodology used to automate the CFD and shape optimization procedures is discussed. In the first phase, single and multi-variable optimization methods, coupled with CFD, are applied to simplified 2-D radiator models to investigate effects of inlet and outlet positions on the above functions. The second phase concentrates on CFD simulations of a simplified 3-D radiator model. The results, which show possible improvements in both pressure and flow uniformity, validate the optimization criteria that were developed, as well as the potential of shape optimization methods with CFD to improve heat exchanger design. * Improving Radiator Design Through Shape Optimization, L. Guessous and S. Maddipatla, Paper # IMECE2002-33888, Proceedings of the 2002 ASME International Mechanical Engineering Congress and Exposition, November 2002

  3. Tensor-optimized antisymmetrized molecular dynamics in nuclear physics

    NASA Astrophysics Data System (ADS)

    Myo, Takayuki; Toki, Hiroshi; Ikeda, Kiyomi; Horiuchi, Hisashi; Suhara, Tadahiro

    2015-07-01

    We develop a new formalism to treat nuclear many-body systems using the bare nucleon-nucleon interaction. It has become evident that the tensor interaction plays an important role in nuclear many-body systems due to the role of the pion in strongly interacting systems. We take the antisymmetrized molecular dynamics (AMD) as a basic framework and add a tensor correlation operator acting on the AMD wave function using the concept of the tensor-optimized shell model. We demonstrate a systematical and straightforward formulation utilizing the Gaussian integration and differentiation method and the antisymmetrization technique to calculate all the matrix elements of the many-body Hamiltonian. We can include the three-body interaction naturally and calculate the matrix elements systematically in the progressive order of the tensor correlation operator. We call the new formalism "tensor-optimized antisymmetrized molecular dynamics".

  4. Optimizing airport runway improvement program - A dynamic programming approach

    NASA Technical Reports Server (NTRS)

    Yu, J. C.; Gibson, D. R.

    1975-01-01

    In order to reduce the air traffic delay in the terminal area, an immediate remedy is to increase airport capacity by an expansion of the existing runway system. The runway expansion program is often limited by budgetary constraints; the expensive facilities for a long-term improvement cannot be built at once. When a runway improvement strategy is being considered for a longer planning horizon, the investiment decision depends upon the interrelations of its composite periods. The problem, therefore, is to determine how time factor and investment decisions interact to yield an optimal improvement scheme that meets demand at a minimum cost. With this objective in mind, a dynamic programming methodology is employed to determine the optimal planning scheme. Also, an example runway improvement problem is tested to illustrate how a dynamic programming model is practical in actual application.

  5. A Dynamically Optimized SSVEP Brain-Computer Interface (BCI) Speller.

    PubMed

    Yin, Erwei; Zhou, Zongtan; Jiang, Jun; Yu, Yang; Hu, Dewen

    2015-06-01

    The aim of this study was to design a dynamically optimized steady-state visually evoked potential (SSVEP) brain-computer interface (BCI) system with enhanced performance relative to previous SSVEP BCIs in terms of the number of items selectable on the interface, accuracy, and speed. In this approach, the row/column (RC) paradigm was employed in a SSVEP speller to increase the number of items. The target is detected by subsequently determining the row and column coordinates. To improve spelling accuracy, we added a posterior processing after the canonical correlation analysis (CCA) approach to reduce the interfrequency variation between different subjects and named the new signal processing method CCA-RV, and designed a real-time biofeedback mechanism to increase attention on the visual stimuli. To achieve reasonable online spelling speed, both fixed and dynamic approaches for setting the optimal stimulus duration were implemented and compared. Experimental results for 11 subjects suggest that the CCA-RV method and the real-time biofeedback effectively increased accuracy compared with CCA and the absence of real-time feedback, respectively. In addition, both optimization approaches for setting stimulus duration achieved reasonable online spelling performance. However, the dynamic optimization approach yielded a higher practical information transfer rate (PITR) than the fixed optimization approach. The average online PITR achieved by the proposed adaptive SSVEP speller, including the time required for breaks between selections and error correction, was 41.08 bit/min. These results indicate that our BCI speller is promising for use in SSVEP-based BCI applications. PMID:24801483

  6. Rethinking design parameters in the search for optimal dynamic seating.

    PubMed

    Pynt, Jennifer

    2015-04-01

    Dynamic seating design purports to lessen damage incurred during sedentary occupations by increasing sitter movement while modifying muscle activity. Dynamic sitting is currently defined by O'Sullivan et al. ( 2013a) as relating to 'the increased motion in sitting which is facilitated by the use of specific chairs or equipment' (p. 628). Yet the evidence is conflicting that dynamic seating creates variation in the sitter's lumbar posture or muscle activity with the overall consensus being that current dynamic seating design fails to fulfill its goals. Research is needed to determine if a new generation of chairs requiring active sitter involvement fulfills the goals of dynamic seating and aids cardio/metabolic health. This paper summarises the pursuit of knowledge regarding optimal seated spinal posture and seating design. Four new forms of dynamic seating encouraging active sitting are discussed. These are 1) The Core-flex with a split seatpan to facilitate a walking action while seated 2) the Duo balans requiring body action to create rocking 3) the Back App and 4) Locus pedestal stools both using the sitter's legs to drive movement. Unsubstantiated claims made by the designers of these new forms of dynamic seating are outlined. Avenues of research are suggested to validate designer claims and investigate whether these designs fulfill the goals of dynamic seating and assist cardio/metabolic health. Should these claims be efficacious then a new definition of dynamic sitting is suggested; 'Sitting in which the action is provided by the sitter, while the dynamic mechanism of the chair accommodates that action'. PMID:25892386

  7. Optimally combining dynamical decoupling and quantum error correction.

    PubMed

    Paz-Silva, Gerardo A; Lidar, D A

    2013-01-01

    Quantum control and fault-tolerant quantum computing (FTQC) are two of the cornerstones on which the hope of realizing a large-scale quantum computer is pinned, yet only preliminary steps have been taken towards formalizing the interplay between them. Here we explore this interplay using the powerful strategy of dynamical decoupling (DD), and show how it can be seamlessly and optimally integrated with FTQC. To this end we show how to find the optimal decoupling generator set (DGS) for various subspaces relevant to FTQC, and how to simultaneously decouple them. We focus on stabilizer codes, which represent the largest contribution to the size of the DGS, showing that the intuitive choice comprising the stabilizers and logical operators of the code is in fact optimal, i.e., minimizes a natural cost function associated with the length of DD sequences. Our work brings hybrid DD-FTQC schemes, and their potentially considerable advantages, closer to realization. PMID:23559088

  8. Optimally combining dynamical decoupling and quantum error correction

    PubMed Central

    Paz-Silva, Gerardo A.; Lidar, D. A.

    2013-01-01

    Quantum control and fault-tolerant quantum computing (FTQC) are two of the cornerstones on which the hope of realizing a large-scale quantum computer is pinned, yet only preliminary steps have been taken towards formalizing the interplay between them. Here we explore this interplay using the powerful strategy of dynamical decoupling (DD), and show how it can be seamlessly and optimally integrated with FTQC. To this end we show how to find the optimal decoupling generator set (DGS) for various subspaces relevant to FTQC, and how to simultaneously decouple them. We focus on stabilizer codes, which represent the largest contribution to the size of the DGS, showing that the intuitive choice comprising the stabilizers and logical operators of the code is in fact optimal, i.e., minimizes a natural cost function associated with the length of DD sequences. Our work brings hybrid DD-FTQC schemes, and their potentially considerable advantages, closer to realization. PMID:23559088

  9. Confronting dynamics and uncertainty in optimal decision making for conservation

    USGS Publications Warehouse

    Williams, Byron K.; Johnson, Fred A.

    2013-01-01

    The effectiveness of conservation efforts ultimately depends on the recognition that decision making, and the systems that it is designed to affect, are inherently dynamic and characterized by multiple sources of uncertainty. To cope with these challenges, conservation planners are increasingly turning to the tools of decision analysis, especially dynamic optimization methods. Here we provide a general framework for optimal, dynamic conservation and then explore its capacity for coping with various sources and degrees of uncertainty. In broadest terms, the dynamic optimization problem in conservation is choosing among a set of decision options at periodic intervals so as to maximize some conservation objective over the planning horizon. Planners must account for immediate objective returns, as well as the effect of current decisions on future resource conditions and, thus, on future decisions. Undermining the effectiveness of such a planning process are uncertainties concerning extant resource conditions (partial observability), the immediate consequences of decision choices (partial controllability), the outcomes of uncontrolled, environmental drivers (environmental variation), and the processes structuring resource dynamics (structural uncertainty). Where outcomes from these sources of uncertainty can be described in terms of probability distributions, a focus on maximizing the expected objective return, while taking state-specific actions, is an effective mechanism for coping with uncertainty. When such probability distributions are unavailable or deemed unreliable, a focus on maximizing robustness is likely to be the preferred approach. Here the idea is to choose an action (or state-dependent policy) that achieves at least some minimum level of performance regardless of the (uncertain) outcomes. We provide some examples of how the dynamic optimization problem can be framed for problems involving management of habitat for an imperiled species, conservation of a critically endangered population through captive breeding, control of invasive species, construction of biodiversity reserves, design of landscapes to increase habitat connectivity, and resource exploitation. Although these decision making problems and their solutions present significant challenges, we suggest that a systematic and effective approach to dynamic decision making in conservation need not be an onerous undertaking. The requirements are shared with any systematic approach to decision making--a careful consideration of values, actions, and outcomes.

  10. Confronting dynamics and uncertainty in optimal decision making for conservation

    NASA Astrophysics Data System (ADS)

    Williams, Byron K.; Johnson, Fred A.

    2013-06-01

    The effectiveness of conservation efforts ultimately depends on the recognition that decision making, and the systems that it is designed to affect, are inherently dynamic and characterized by multiple sources of uncertainty. To cope with these challenges, conservation planners are increasingly turning to the tools of decision analysis, especially dynamic optimization methods. Here we provide a general framework for optimal, dynamic conservation and then explore its capacity for coping with various sources and degrees of uncertainty. In broadest terms, the dynamic optimization problem in conservation is choosing among a set of decision options at periodic intervals so as to maximize some conservation objective over the planning horizon. Planners must account for immediate objective returns, as well as the effect of current decisions on future resource conditions and, thus, on future decisions. Undermining the effectiveness of such a planning process are uncertainties concerning extant resource conditions (partial observability), the immediate consequences of decision choices (partial controllability), the outcomes of uncontrolled, environmental drivers (environmental variation), and the processes structuring resource dynamics (structural uncertainty). Where outcomes from these sources of uncertainty can be described in terms of probability distributions, a focus on maximizing the expected objective return, while taking state-specific actions, is an effective mechanism for coping with uncertainty. When such probability distributions are unavailable or deemed unreliable, a focus on maximizing robustness is likely to be the preferred approach. Here the idea is to choose an action (or state-dependent policy) that achieves at least some minimum level of performance regardless of the (uncertain) outcomes. We provide some examples of how the dynamic optimization problem can be framed for problems involving management of habitat for an imperiled species, conservation of a critically endangered population through captive breeding, control of invasive species, construction of biodiversity reserves, design of landscapes to increase habitat connectivity, and resource exploitation. Although these decision making problems and their solutions present significant challenges, we suggest that a systematic and effective approach to dynamic decision making in conservation need not be an onerous undertaking. The requirements are shared with any systematic approach to decision making—a careful consideration of values, actions, and outcomes.

  11. Optimal forwarding ratio on dynamical networks with heterogeneous mobility

    NASA Astrophysics Data System (ADS)

    Gan, Yu; Tang, Ming; Yang, Hanxin

    2013-05-01

    Since the discovery of non-Poisson statistics of human mobility trajectories, more attention has been paid to understand the role of these patterns in different dynamics. In this study, we first introduce the heterogeneous mobility of mobile agents into dynamical networks, and then investigate packet forwarding strategy on the heterogeneous dynamical networks. We find that the faster speed and the higher proportion of high-speed agents can enhance the network throughput and reduce the mean traveling time in random forwarding. A hierarchical structure in the dependence of high-speed is observed: the network throughput remains unchanged at small and large high-speed value. It is also interesting to find that a slightly preferential forwarding to high-speed agents can maximize the network capacity. Through theoretical analysis and numerical simulations, we show that the optimal forwarding ratio stems from the local structural heterogeneity of low-speed agents.

  12. Human opinion dynamics: An inspiration to solve complex optimization problems

    PubMed Central

    Kaur, Rishemjit; Kumar, Ritesh; Bhondekar, Amol P.; Kapur, Pawan

    2013-01-01

    Human interactions give rise to the formation of different kinds of opinions in a society. The study of formations and dynamics of opinions has been one of the most important areas in social physics. The opinion dynamics and associated social structure leads to decision making or so called opinion consensus. Opinion formation is a process of collective intelligence evolving from the integrative tendencies of social influence with the disintegrative effects of individualisation, and therefore could be exploited for developing search strategies. Here, we demonstrate that human opinion dynamics can be utilised to solve complex mathematical optimization problems. The results have been compared with a standard algorithm inspired from bird flocking behaviour and the comparison proves the efficacy of the proposed approach in general. Our investigation may open new avenues towards understanding the collective decision making. PMID:24141795

  13. Optimal flow rates and well locations for soil vapor extraction design

    NASA Astrophysics Data System (ADS)

    Sawyer, Charles S.; Kamakoti, Madhavi

    1998-07-01

    A mixed-integer programming model to determine the optimum number of wells, their locations and pumping rates for soil vapor extraction (SVE) is developed by coupling an air flow simulation model (AIR3D) to the GAMS optimization software. The model was tested for sensitivity of the vertical discretization of the domain, the number of potential well locations, the number of constraints, and the screen length of the wells. It was shown that these variables affected the optimal solution. It was also shown that the installation costs of the wells in the model influenced the optimal design. This was demonstrated by comparing the results of the mixed-integer programming model to a linear programming model in which the installation costs of the wells were neglected. The mixed-integer programming model could be useful in the design process in cases of short remediation times when the installation costs of wells could be significant. Numerous test cases with results are presented to demonstrate the applicability and usefulness of the model.

  14. Optimized Uncertainty Quantification Algorithm Within a Dynamic Event Tree Framework

    SciTech Connect

    J. W. Nielsen; Akira Tokuhiro; Robert Hiromoto

    2014-06-01

    Methods for developing Phenomenological Identification and Ranking Tables (PIRT) for nuclear power plants have been a useful tool in providing insight into modelling aspects that are important to safety. These methods have involved expert knowledge with regards to reactor plant transients and thermal-hydraulic codes to identify are of highest importance. Quantified PIRT provides for rigorous method for quantifying the phenomena that can have the greatest impact. The transients that are evaluated and the timing of those events are typically developed in collaboration with the Probabilistic Risk Analysis. Though quite effective in evaluating risk, traditional PRA methods lack the capability to evaluate complex dynamic systems where end states may vary as a function of transition time from physical state to physical state . Dynamic PRA (DPRA) methods provide a more rigorous analysis of complex dynamic systems. A limitation of DPRA is its potential for state or combinatorial explosion that grows as a function of the number of components; as well as, the sampling of transition times from state-to-state of the entire system. This paper presents a method for performing QPIRT within a dynamic event tree framework such that timing events which result in the highest probabilities of failure are captured and a QPIRT is performed simultaneously while performing a discrete dynamic event tree evaluation. The resulting simulation results in a formal QPIRT for each end state. The use of dynamic event trees results in state explosion as the number of possible component states increases. This paper utilizes a branch and bound algorithm to optimize the solution of the dynamic event trees. The paper summarizes the methods used to implement the branch-and-bound algorithm in solving the discrete dynamic event trees.

  15. Optimizing spread dynamics on graphs by message passing

    NASA Astrophysics Data System (ADS)

    Altarelli, F.; Braunstein, A.; Dall'Asta, L.; Zecchina, R.

    2013-09-01

    Cascade processes are responsible for many important phenomena in natural and social sciences. Simple models of irreversible dynamics on graphs, in which nodes activate depending on the state of their neighbors, have been successfully applied to describe cascades in a large variety of contexts. Over the past decades, much effort has been devoted to understanding the typical behavior of the cascades arising from initial conditions extracted at random from some given ensemble. However, the problem of optimizing the trajectory of the system, i.e. of identifying appropriate initial conditions to maximize (or minimize) the final number of active nodes, is still considered to be practically intractable, with the only exception being models that satisfy a sort of diminishing returns property called submodularity. Submodular models can be approximately solved by means of greedy strategies, but by definition they lack cooperative characteristics which are fundamental in many real systems. Here we introduce an efficient algorithm based on statistical physics for the optimization of trajectories in cascade processes on graphs. We show that for a wide class of irreversible dynamics, even in the absence of submodularity, the spread optimization problem can be solved efficiently on large networks. Analytic and algorithmic results on random graphs are complemented by the solution of the spread maximization problem on a real-world network (the Epinions consumer reviews network).

  16. Dynamic optimization of bioprocesses: efficient and robust numerical strategies.

    PubMed

    Banga, Julio R; Balsa-Canto, Eva; Moles, Carmen G; Alonso, Antonio A

    2005-06-29

    The dynamic optimization (open loop optimal control) of non-linear bioprocesses is considered in this contribution. These processes can be described by sets of non-linear differential and algebraic equations (DAEs), usually subject to constraints in the state and control variables. A review of the available solution techniques for this class of problems is presented, highlighting the numerical difficulties arising from the non-linear, constrained and often discontinuous nature of these systems. In order to surmount these difficulties, we present several alternative stochastic and hybrid techniques based on the control vector parameterization (CVP) approach. The CVP approach is a direct method which transforms the original problem into a non-linear programming (NLP) problem, which must be solved by a suitable (efficient and robust) solver. In particular, a hybrid technique uses a first global optimization phase followed by a fast second phase based on a local deterministic method, so it can handle the nonconvexity of many of these NLPs. The efficiency and robustness of these techniques is illustrated by solving several challenging case studies regarding the optimal control of fed-batch bioreactors and other bioprocesses. In order to fairly evaluate their advantages, a careful and critical comparison with several other direct approaches is provided. The results indicate that the two-phase hybrid approach presents the best compromise between robustness and efficiency. PMID:15888349

  17. Active flutter control using discrete optimal constrained dynamic compensators

    NASA Technical Reports Server (NTRS)

    Broussard, J. R.; Halyo, N.

    1983-01-01

    A method for synthesizing digital active flutter suppression controllers using the concept of optimal output feedback is presented. A recently developd convergent algorithm is employed to determine constrained control law parameters that minimize an infinite-time discrete quadratic performance index. Low-order compensator dynamics are included in the control law and the compensator parameters are computed along with the output feedback gain as part of the optimization process. An input noise adjustment procedure is used to improve the stability margins of the digital active flutter controller. Results from investigations into sample rate variation, prefilter pole variation, and effects of varying flight condtions are discussed. The study indicates that a digital control law which accommodates computation delay can stabilize the wing with reasonable rms performance and adequate stability margins.

  18. Optimal Dynamic Regimes: Presenting a Case for Predictive Inference

    PubMed Central

    Arjas, Elja; Saarela, Olli

    2010-01-01

    Dynamic treatment regime is a decision rule in which the choice of the treatment of an individual at any given time can depend on the known past history of that individual, including baseline covariates, earlier treatments, and their measured responses. In this paper we argue that finding an optimal regime can, at least in moderately simple cases, be accomplished by a straightforward application of nonparametric Bayesian modeling and predictive inference. As an illustration we consider an inference problem in a subset of the Multicenter AIDS Cohort Study (MACS) data set, studying the effect of AZT initiation on future CD4-cell counts during a 12-month follow-up. PMID:20648215

  19. Designing area optimized application-specific network-on-chip architectures while providing hard QoS guarantees.

    PubMed

    Khawaja, Sajid Gul; Mushtaq, Mian Hamza; Khan, Shoab A; Akram, M Usman; Jamal, Habib Ullah

    2015-01-01

    With the increase of transistors' density, popularity of System on Chip (SoC) has increased exponentially. As a communication module for SoC, Network on Chip (NoC) framework has been adapted as its backbone. In this paper, we propose a methodology for designing area-optimized application specific NoC while providing hard Quality of Service (QoS) guarantees for real time flows. The novelty of the proposed system lies in derivation of a Mixed Integer Linear Programming model which is then used to generate a resource optimal Network on Chip (NoC) topology and architecture while considering traffic and QoS requirements. We also present the micro-architectural design features used for enabling traffic and latency guarantees and discuss how the solution adapts for dynamic variations in the application traffic. The paper highlights the effectiveness of proposed method by generating resource efficient NoC solutions for both industrial and benchmark applications. The area-optimized results are generated in few seconds by proposed technique, without resorting to heuristics, even for an application with 48 traffic flows. PMID:25898016

  20. Designing Area Optimized Application-Specific Network-On-Chip Architectures while Providing Hard QoS Guarantees

    PubMed Central

    Khawaja, Sajid Gul; Mushtaq, Mian Hamza; Khan, Shoab A.; Akram, M. Usman; Jamal, Habib ullah

    2015-01-01

    With the increase of transistors' density, popularity of System on Chip (SoC) has increased exponentially. As a communication module for SoC, Network on Chip (NoC) framework has been adapted as its backbone. In this paper, we propose a methodology for designing area-optimized application specific NoC while providing hard Quality of Service (QoS) guarantees for real time flows. The novelty of the proposed system lies in derivation of a Mixed Integer Linear Programming model which is then used to generate a resource optimal Network on Chip (NoC) topology and architecture while considering traffic and QoS requirements. We also present the micro-architectural design features used for enabling traffic and latency guarantees and discuss how the solution adapts for dynamic variations in the application traffic. The paper highlights the effectiveness of proposed method by generating resource efficient NoC solutions for both industrial and benchmark applications. The area-optimized results are generated in few seconds by proposed technique, without resorting to heuristics, even for an application with 48 traffic flows. PMID:25898016

  1. Optimization of phonon dynamics protocols in ion traps

    NASA Astrophysics Data System (ADS)

    Dutta, T.; Mukherjee, M.; Sengupta, K.

    2016-03-01

    We develop a theory to address the non equilibrium dynamics of phonons in a one-dimensional finite size trapped ion system for non linear ramp and periodic protocols. Our analysis, which is based on our earlier proposal of dynamics-induced cooling and entanglement generation between phonons in these systems when subjected to a linear ramp protocol [1], identifies the optimal protocol within the above-mentioned classes, which minimizes both the cooling and entanglement generation time. We also introduce single-/two-site addressing to achieve cooling/entanglement, which is expected to lead to simpler implementation of these protocols. Finally, we discuss the effect of noise due to the fluctuation of the intensity of the laser used to generate the trap on entanglement generation. We also discuss realistic experimental setups that may serve as test beds for our theory.

  2. Dynamic Simulation and Optimization of Nuclear Hydrogen Production Systems

    SciTech Connect

    Paul I. Barton; Mujid S. Kaximi; Georgios Bollas; Patricio Ramirez Munoz

    2009-07-31

    This project is part of a research effort to design a hydrogen plant and its interface with a nuclear reactor. This project developed a dynamic modeling, simulation and optimization environment for nuclear hydrogen production systems. A hybrid discrete/continuous model captures both the continuous dynamics of the nuclear plant, the hydrogen plant, and their interface, along with discrete events such as major upsets. This hybrid model makes us of accurate thermodynamic sub-models for the description of phase and reaction equilibria in the thermochemical reactor. Use of the detailed thermodynamic models will allow researchers to examine the process in detail and have confidence in the accurary of the property package they use.

  3. Optimized dynamical decoupling for power-law noise spectra

    SciTech Connect

    Pasini, S.; Uhrig, G. S.

    2010-01-15

    We analyze the suppression of decoherence by means of dynamical decoupling in the pure-dephasing spin-boson model for baths with power law spectra. The sequence of ideal pi pulses is optimized according to the power of the bath. We expand the decoherence function and separate the canceling divergences from the relevant terms. The proposed sequence is chosen to be the one minimizing the decoherence function. By construction, it provides the best performance. We analytically derive the conditions that must be satisfied. The resulting equations are solved numerically. The solutions are very close to the Carr-Purcell-Meiboom-Gill sequence for a soft cutoff of the bath while they approach the Uhrig dynamical-decoupling sequence as the cutoff becomes harder.

  4. Clustering molecular dynamics trajectories for optimizing docking experiments.

    PubMed

    De Paris, Renata; Quevedo, Christian V; Ruiz, Duncan D; Norberto de Souza, Osmar; Barros, Rodrigo C

    2015-01-01

    Molecular dynamics simulations of protein receptors have become an attractive tool for rational drug discovery. However, the high computational cost of employing molecular dynamics trajectories in virtual screening of large repositories threats the feasibility of this task. Computational intelligence techniques have been applied in this context, with the ultimate goal of reducing the overall computational cost so the task can become feasible. Particularly, clustering algorithms have been widely used as a means to reduce the dimensionality of molecular dynamics trajectories. In this paper, we develop a novel methodology for clustering entire trajectories using structural features from the substrate-binding cavity of the receptor in order to optimize docking experiments on a cloud-based environment. The resulting partition was selected based on three clustering validity criteria, and it was further validated by analyzing the interactions between 20 ligands and a fully flexible receptor (FFR) model containing a 20 ns molecular dynamics simulation trajectory. Our proposed methodology shows that taking into account features of the substrate-binding cavity as input for the k-means algorithm is a promising technique for accurately selecting ensembles of representative structures tailored to a specific ligand. PMID:25873944

  5. Clustering Molecular Dynamics Trajectories for Optimizing Docking Experiments

    PubMed Central

    De Paris, Renata; Quevedo, Christian V.; Ruiz, Duncan D.; Norberto de Souza, Osmar; Barros, Rodrigo C.

    2015-01-01

    Molecular dynamics simulations of protein receptors have become an attractive tool for rational drug discovery. However, the high computational cost of employing molecular dynamics trajectories in virtual screening of large repositories threats the feasibility of this task. Computational intelligence techniques have been applied in this context, with the ultimate goal of reducing the overall computational cost so the task can become feasible. Particularly, clustering algorithms have been widely used as a means to reduce the dimensionality of molecular dynamics trajectories. In this paper, we develop a novel methodology for clustering entire trajectories using structural features from the substrate-binding cavity of the receptor in order to optimize docking experiments on a cloud-based environment. The resulting partition was selected based on three clustering validity criteria, and it was further validated by analyzing the interactions between 20 ligands and a fully flexible receptor (FFR) model containing a 20 ns molecular dynamics simulation trajectory. Our proposed methodology shows that taking into account features of the substrate-binding cavity as input for the k-means algorithm is a promising technique for accurately selecting ensembles of representative structures tailored to a specific ligand. PMID:25873944

  6. Aircraft path planning for optimal imaging using dynamic cost functions

    NASA Astrophysics Data System (ADS)

    Christie, Gordon; Chaudhry, Haseeb; Kochersberger, Kevin

    2015-05-01

    Unmanned aircraft development has accelerated with recent technological improvements in sensing and communications, which has resulted in an "applications lag" for how these aircraft can best be utilized. The aircraft are becoming smaller, more maneuverable and have longer endurance to perform sensing and sampling missions, but operating them aggressively to exploit these capabilities has not been a primary focus in unmanned systems development. This paper addresses a means of aerial vehicle path planning to provide a realistic optimal path in acquiring imagery for structure from motion (SfM) reconstructions and performing radiation surveys. This method will allow SfM reconstructions to occur accurately and with minimal flight time so that the reconstructions can be executed efficiently. An assumption is made that we have 3D point cloud data available prior to the flight. A discrete set of scan lines are proposed for the given area that are scored based on visibility of the scene. Our approach finds a time-efficient path and calculates trajectories between scan lines and over obstacles encountered along those scan lines. Aircraft dynamics are incorporated into the path planning algorithm as dynamic cost functions to create optimal imaging paths in minimum time. Simulations of the path planning algorithm are shown for an urban environment. We also present our approach for image-based terrain mapping, which is able to efficiently perform a 3D reconstruction of a large area without the use of GPS data.

  7. Data-driven optimization of dynamic reconfigurable systems of systems.

    SciTech Connect

    Tucker, Conrad S.; Eddy, John P.

    2010-11-01

    This report documents the results of a Strategic Partnership (aka University Collaboration) LDRD program between Sandia National Laboratories and the University of Illinois at Urbana-Champagne. The project is titled 'Data-Driven Optimization of Dynamic Reconfigurable Systems of Systems' and was conducted during FY 2009 and FY 2010. The purpose of this study was to determine and implement ways to incorporate real-time data mining and information discovery into existing Systems of Systems (SoS) modeling capabilities. Current SoS modeling is typically conducted in an iterative manner in which replications are carried out in order to quantify variation in the simulation results. The expense of many replications for large simulations, especially when considering the need for optimization, sensitivity analysis, and uncertainty quantification, can be prohibitive. In addition, extracting useful information from the resulting large datasets is a challenging task. This work demonstrates methods of identifying trends and other forms of information in datasets that can be used on a wide range of applications such as quantifying the strength of various inputs on outputs, identifying the sources of variation in the simulation, and potentially steering an optimization process for improved efficiency.

  8. Optimizing Groundwater Remediation Designs Under Uncertainty Using Dynamic Surrogate Models

    NASA Astrophysics Data System (ADS)

    Yan, S.; Minsker, B.

    2005-12-01

    Computational cost is a critical issue for large-scale water resource optimization problems that often involve time-consuming simulation models. This issue is compounded when optimizing under uncertainty, since Monte Carlo simulations are often required to evaluate objective function values over multiple parameter realizations. In order to improve computational efficiency, we propose a soft computing approach, in which the time-consuming numerical models are approximated and replaced by dynamic surrogates embedded within a noisy genetic algorithm (GA) optimization framework. The surrogates are trained to predict the distribution of the objectives online, using Monte Carlo simulation results created during the GA run. The surrogates are then adaptively updated to improve their prediction performance and correct the GA's convergence as the search progresses. Latin Hypercube sampling method is used to efficiently sample parameters for the Monte Carlo simulation and the sampling results are archived so that the estimation of the objective function distributions is progressively improved. The GA is modified to incorporate hypothesis tests to produce reliable solutions. The method is applied to two groundwater remediation design case studies, where the primary source of uncertainty stems from hydraulic conductivity values in the aquifers. Our preliminary results show that the technique can lead to reliable and cost-effective solutions with significantly less computational effort.

  9. Assessment of optimally filtered recent geodetic mean dynamic topographies

    NASA Astrophysics Data System (ADS)

    Siegismund, F.

    2013-01-01

    AbstractRecent geoids from the Gravity Recovery and Climate Experiment (GRACE) and the Gravity field and steady state Ocean Circulation Explorer satellite mission (GOCE) contain useful short-scale information for the construction of a geodetic ocean mean <span class="hlt">dynamic</span> topography (MDT). The geodetic MDT is obtained from subtracting the geoid from a mean sea surface (MSS) as measured by satellite altimetry. A gainful use of the MDT and an adequate assessment needs an <span class="hlt">optimal</span> filtering. This is accomplished here by defining a cutoff length scale dmax for the geoid and applying a Gaussian filter with half-width radius r on the MDT. A series of MDTs (GRACE, GOCE, and combined satellite-only (GOCO) solutions) is tested, using different sets of filter parameters dmax and r. <span class="hlt">Optimal</span> global and regional dependent filter parameters are estimated. To find <span class="hlt">optimal</span> parameters and to assess the resulting MDTs, the geostrophic surface currents induced by the filtered geodetic MDT are compared to corrected near-surface currents obtained from the Global Drifter Program (GDP). The global <span class="hlt">optimal</span> cutoff degree and order (d/o) dmax (half-width radius r of the spatial Gaussian filter) is 160 (1.1°) for GRACE; 180 (1.1-1.2°) for 1st releases of GOCE (time- and space-wise methods) and GOCO models; and 210 (1.0 degree) for 2nd and 3rd releases of GOCE and GOCO models. The cutoff d/o is generally larger (smaller) and the filter length smaller (larger) for regions with strong, small-scale (slow, broad scale) currents. The smallest deviations from the drifter data are obtained with the GOCO03s geoid model, although deviations of other models are only slightly higher.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140011905','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140011905"><span id="translatedtitle">A Formal Approach to Empirical <span class="hlt">Dynamic</span> Model <span class="hlt">Optimization</span> and Validation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Crespo, Luis G; Morelli, Eugene A.; Kenny, Sean P.; Giesy, Daniel P.</p> <p>2014-01-01</p> <p>A framework was developed for the <span class="hlt">optimization</span> and validation of empirical <span class="hlt">dynamic</span> models subject to an arbitrary set of validation criteria. The validation requirements imposed upon the model, which may involve several sets of input-output data and arbitrary specifications in time and frequency domains, are used to determine if model predictions are within admissible error limits. The parameters of the empirical model are estimated by finding the parameter realization for which the smallest of the margins of requirement compliance is as large as possible. The uncertainty in the value of this estimate is characterized by studying the set of model parameters yielding predictions that comply with all the requirements. Strategies are presented for bounding this set, studying its dependence on admissible prediction error set by the analyst, and evaluating the sensitivity of the model predictions to parameter variations. This information is instrumental in characterizing uncertainty models used for evaluating the <span class="hlt">dynamic</span> model at operating conditions differing from those used for its identification and validation. A practical example based on the short period <span class="hlt">dynamics</span> of the F-16 is used for illustration.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/835380','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/835380"><span id="translatedtitle">Performance Study and <span class="hlt">Dynamic</span> <span class="hlt">Optimization</span> Design for Thread Pool Systems</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Dongping Xu</p> <p>2004-12-19</p> <p>Thread pools have been widely used by many multithreaded applications. However, the determination of the pool size according to the application behavior still remains problematic. To automate this process, in this thesis we have developed a set of performance metrics for quantitatively analyzing thread pool performance. For our experiments, we built a thread pool system which provides a general framework for thread pool research. Based on this simulation environment, we studied the performance impact brought by the thread pool on different multithreaded applications. Additionally, the correlations between internal characterizations of thread pools and their throughput were also examined. We then proposed and evaluated a heuristic algorithm to <span class="hlt">dynamically</span> determine the <span class="hlt">optimal</span> thread pool size. The simulation results show that this approach is effective in improving overall application performance.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22594832','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22594832"><span id="translatedtitle">Learning the <span class="hlt">dynamics</span> of objects by <span class="hlt">optimal</span> functional interpolation.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ahn, Jong-Hoon; Kim, In Young</p> <p>2012-09-01</p> <p>Many areas of science and engineering rely on functional data and their numerical analysis. The need to analyze time-varying functional data raises the general problem of interpolation, that is, how to learn a smooth time evolution from a finite number of observations. Here, we introduce <span class="hlt">optimal</span> functional interpolation (OFI), a numerical algorithm that interpolates functional data over time. Unlike the usual interpolation or learning algorithms, the OFI algorithm obeys the continuity equation, which describes the transport of some types of conserved quantities, and its implementation shows smooth, continuous flows of quantities. Without the need to take into account equations of motion such as the Navier-Stokes equation or the diffusion equation, OFI is capable of learning the <span class="hlt">dynamics</span> of objects such as those represented by mass, image intensity, particle concentration, heat, spectral density, and probability density. PMID:22594832</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/937624','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/937624"><span id="translatedtitle">A relaxed reduced space SQP strategy for <span class="hlt">dynamic</span> <span class="hlt">optimization</span> problems.</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Logsdon, J. S.; Biegler, L. T.; Carnegie-Mellon Univ.</p> <p>1993-01-01</p> <p>Recently, strategies have been developed to solve <span class="hlt">dynamic</span> simulation and <span class="hlt">optimization</span> problems in a simultaneous manner by applying orthogonal collocation on finite elements and solving the nonlinear program (NLP) with a reduced space successive quadratic programming (SQP) approach. We develop a relaxed simultaneous approach that leads to faster performance. The method operates in the reduced space of the control variables and solves the collocation equations inexactly at each SQP iteration. Unlike previous simultaneous formulations, it is able to consider the state variables one element at a time. Also, this approach is compared on two process examples to the reduced gradient, feasible path approach outlined in Logsdon and Biegler. Nonlinear programs with up to 5500 variables are solved with only 40% of the effort. Finally, a theoretical analysis of this approach is provided.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007SPIE.6540E..0OH','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007SPIE.6540E..0OH"><span id="translatedtitle">Improved self-protection using <span class="hlt">dynamically</span> <span class="hlt">optimized</span> expendable countermeasures</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hovland, Harald</p> <p>2007-04-01</p> <p>The use of expendable countermeasures is still found to be a viable choice for self protection against Man Portable Air Defense Systems (MANPADS) due to their simplicity, low cost, flexibility, recent improvements in decoy technology, the ability to handle multiple threats simultaneously and the off-board nature of these countermeasures. In civil aviation, the risk of general hazards linked to the use of pyrotechnics is the main argument against expendable countermeasures, whereas for military platforms, the limitation in capacity due to a limited number of rounds is often used as an argument to replace expendable countermeasures by laser-based countermeasures. This latter argument is in general not substantiated by modelling or figures of merit, although it is often argued that a laser based system allows for more false alarms, hence enabling a more sensitive missile approach warning system. The author has developed a model that accounts for the statistical effects of running out of expendable countermeasures during a mission, in terms of the overall mission survival probability. The model includes key parameters of the missile approach warning system (MAWS), and can handle multiple missile types and missile attack configurations, as well as various statistical models of missile attacks. The model enables quantitative comparison between laser based and expendable countermeasures, but also a <span class="hlt">dynamic</span> <span class="hlt">optimization</span> of the countermeasures in terms of whether to use small or large countermeasure programs, as well as the <span class="hlt">dynamic</span> tuning of MAWS key parameters to <span class="hlt">optimize</span> the overall performance. The model is also well suited for determination of the contributions of the different components of the system in the overall survival probability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AIPC..985.1445T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AIPC..985.1445T"><span id="translatedtitle"><span class="hlt">Optimal</span> Pulse-Tube Design Using Computational Fluid <span class="hlt">Dynamics</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Taylor, R. P.; Nellis, G. F.; Klein, S. A.</p> <p>2008-03-01</p> <p>Over the past few decades, the pulse-tube cryocooler has advanced from a curiosity to one of the most attractive systems for providing reliable cryogenic cooling; it is now used in aerospace, medical and superconductor applications. This technology development has been enabled by the simulation tools that are available for regenerator, compressor, and inertance tube design. However, a dedicated design tool for the pulse-tube component in a pulse-tube cryocooler and the associated flow transitions between the pulse tube and the regenerator and the pulse tube and the inertance network is not currently available. This paper describes the development of a two-dimensional, axisymmetric computational fluid <span class="hlt">dynamic</span> (CFD) model of the pulse-tube and its associated flow transitions. The model is implemented in the commercial CFD package FLUENT. The CFD simulations are sufficient to calculate and delineate the various loss mechanisms; these are reported as a percentage of the acoustic power that is present at the cold end. A gross figure of merit (the pulse tube efficiency) is defined as the ratio of the useful cooling provided to the available acoustic power. The practical uses (e.g., identification of the <span class="hlt">optimal</span> geometric design) and limitations of the model are discussed and some initial <span class="hlt">optimization</span> results are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014RScI...85i5002Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014RScI...85i5002Y"><span id="translatedtitle">Geometry <span class="hlt">optimization</span> for micro-pressure sensor considering <span class="hlt">dynamic</span> interference</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yu, Zhongliang; Zhao, Yulong; Li, Lili; Tian, Bian; Li, Cun</p> <p>2014-09-01</p> <p>Presented is the geometry <span class="hlt">optimization</span> for piezoresistive absolute micro-pressure sensor. A figure of merit called the performance factor (PF) is defined as a quantitative index to describe the comprehensive performances of a sensor including sensitivity, resonant frequency, and acceleration interference. Three geometries are proposed through introducing islands and sensitive beams into typical flat diaphragm. The stress distributions of sensitive elements are analyzed by finite element method. Multivariate fittings based on ANSYS simulation results are performed to establish the equations about surface stress, deflection, and resonant frequency. <span class="hlt">Optimization</span> by MATLAB is carried out to determine the dimensions of the geometries. Convex corner undercutting is evaluated. Each PF of the three geometries with the determined dimensions is calculated and compared. Silicon bulk micromachining is utilized to fabricate the prototypes of the sensors. The outputs of the sensors under both static and <span class="hlt">dynamic</span> conditions are tested. Experimental results demonstrate the rationality of the defined performance factor and reveal that the geometry with quad islands presents the highest PF of 210.947 Hz1/4. The favorable overall performances enable the sensor more suitable for altimetry.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25273764','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25273764"><span id="translatedtitle">Geometry <span class="hlt">optimization</span> for micro-pressure sensor considering <span class="hlt">dynamic</span> interference.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yu, Zhongliang; Zhao, Yulong; Li, Lili; Tian, Bian; Li, Cun</p> <p>2014-09-01</p> <p>Presented is the geometry <span class="hlt">optimization</span> for piezoresistive absolute micro-pressure sensor. A figure of merit called the performance factor (PF) is defined as a quantitative index to describe the comprehensive performances of a sensor including sensitivity, resonant frequency, and acceleration interference. Three geometries are proposed through introducing islands and sensitive beams into typical flat diaphragm. The stress distributions of sensitive elements are analyzed by finite element method. Multivariate fittings based on ANSYS simulation results are performed to establish the equations about surface stress, deflection, and resonant frequency. <span class="hlt">Optimization</span> by MATLAB is carried out to determine the dimensions of the geometries. Convex corner undercutting is evaluated. Each PF of the three geometries with the determined dimensions is calculated and compared. Silicon bulk micromachining is utilized to fabricate the prototypes of the sensors. The outputs of the sensors under both static and <span class="hlt">dynamic</span> conditions are tested. Experimental results demonstrate the rationality of the defined performance factor and reveal that the geometry with quad islands presents the highest PF of 210.947 Hz(1/4). The favorable overall performances enable the sensor more suitable for altimetry. PMID:25273764</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007SPIE.6576E..0XX','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007SPIE.6576E..0XX"><span id="translatedtitle">Neural <span class="hlt">dynamic</span> <span class="hlt">optimization</span> for autonomous aerial vehicle trajectory design</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xu, Peng; Verma, Ajay; Mayer, Richard J.</p> <p>2007-04-01</p> <p>Online aerial vehicle trajectory design and reshaping are crucial for a class of autonomous aerial vehicles such as reusable launch vehicles in order to achieve flexibility in real-time flying operations. An aerial vehicle is modeled as a nonlinear multi-input-multi-output (MIMO) system. The inputs include the control parameters and current system states that include velocity and position coordinates of the vehicle. The outputs are the new system states. An ideal trajectory control design system generates a series of control commands to achieve a desired trajectory under various disturbances and vehicle model uncertainties including aerodynamic perturbations caused by geometric damage to the vehicle. Conventional approaches suffer from the nonlinearity of the MIMO system, and the high-dimensionality of the system state space. In this paper, we apply a Neural <span class="hlt">Dynamic</span> <span class="hlt">Optimization</span> (NDO) based approach to overcome these difficulties. The core of an NDO model is a multilayer perceptron (MLP) neural network, which generates the control parameters online. The inputs of the MLP are the time-variant states of the MIMO systems. The outputs of the MLP and the control parameters will be used by the MIMO to generate new system states. By such a formulation, an NDO model approximates the time-varying <span class="hlt">optimal</span> feedback solution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1998CoPhC.113..145P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1998CoPhC.113..145P"><span id="translatedtitle"><span class="hlt">Optimization</span> techniques for parallel molecular <span class="hlt">dynamics</span> using domain decomposition</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pütz, M.; Kolb, A.</p> <p>1998-10-01</p> <p>In this paper we describe the implementation of a new parallelized Molecular <span class="hlt">Dynamics</span> code for many-particle problems with short-ranged interactions. While the basic algorithms have their foundation in the fairly standard methods of domain decomposition, linked-cell pair search and Verlet pair list, we have developed some refined techniques for <span class="hlt">optimizing</span> them. The rewards of these <span class="hlt">optimizations</span> are a up to 45% overall improvement in the scalar performance and very good scaling behavior in the number of processors even down to a few hundred particles per processor on a CRAY T3E. The best speedup can be obtained for systems with pair forces only since then the data structures can be organized in a very simple manner. To deal with more complex situations as well, we have developed a partial replicated data scheme which is suitable to simulate many molecules consisting of many simple particles (e.g. polymer chains) for many types of short-range interactions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22314284','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22314284"><span id="translatedtitle">Geometry <span class="hlt">optimization</span> for micro-pressure sensor considering <span class="hlt">dynamic</span> interference</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Yu, Zhongliang; Zhao, Yulong Li, Lili; Tian, Bian; Li, Cun</p> <p>2014-09-15</p> <p>Presented is the geometry <span class="hlt">optimization</span> for piezoresistive absolute micro-pressure sensor. A figure of merit called the performance factor (PF) is defined as a quantitative index to describe the comprehensive performances of a sensor including sensitivity, resonant frequency, and acceleration interference. Three geometries are proposed through introducing islands and sensitive beams into typical flat diaphragm. The stress distributions of sensitive elements are analyzed by finite element method. Multivariate fittings based on ANSYS simulation results are performed to establish the equations about surface stress, deflection, and resonant frequency. <span class="hlt">Optimization</span> by MATLAB is carried out to determine the dimensions of the geometries. Convex corner undercutting is evaluated. Each PF of the three geometries with the determined dimensions is calculated and compared. Silicon bulk micromachining is utilized to fabricate the prototypes of the sensors. The outputs of the sensors under both static and <span class="hlt">dynamic</span> conditions are tested. Experimental results demonstrate the rationality of the defined performance factor and reveal that the geometry with quad islands presents the highest PF of 210.947 Hz{sup 1/4}. The favorable overall performances enable the sensor more suitable for altimetry.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_9 --> <div id="page_10" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="181"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2880540','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2880540"><span id="translatedtitle">Estimating <span class="hlt">Optimal</span> <span class="hlt">Dynamic</span> Regimes: Correcting Bias under the Null</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Moodie, Erica E. M.; Richardson, Thomas S.</p> <p>2009-01-01</p> <p>A <span class="hlt">dynamic</span> regime provides a sequence of treatments that are tailored to patient-specific characteristics and outcomes. In 2004 James Robins proposed g-estimation using structural nested mean models for making inference about the <span class="hlt">optimal</span> <span class="hlt">dynamic</span> regime in a multi-interval trial. The method provides clear advantages over traditional parametric approaches. Robins’ g-estimation method always yields consistent estimators, but these can be asymptotically biased under a given structural nested mean model for certain longitudinal distributions of the treatments and covariates, termed exceptional laws. In fact, under the null hypothesis of no treatment effect, every distribution constitutes an exceptional law under structural nested mean models which allow for interaction of current treatment with past treatments or covariates. This paper provides an explanation of exceptional laws and describes a new approach to g-estimation which we call Zeroing Instead of Plugging In (ZIPI). ZIPI provides nearly identical estimators to recursive g-estimators at non-exceptional laws while providing substantial reduction in the bias at an exceptional law when decision rule parameters are not shared across intervals. PMID:20526433</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JSemi..36i4007Q','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JSemi..36i4007Q"><span id="translatedtitle">4500 V SPT+ IGBT <span class="hlt">optimization</span> on static and <span class="hlt">dynamic</span> losses</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Qingyun, Dai; Xiaoli, Tian; Wenliang, Zhang; Shuojin, Lu; Yangjun, Zhu</p> <p>2015-09-01</p> <p>This paper concerns the need for improving the static and <span class="hlt">dynamic</span> performance of the high voltage insulated gate bipolar transistor (HV IGBTs). A novel structure with a carrier stored layer on the cathode side, known as an enhanced planar IGBT of the 4500 V voltage class is investigated. With the adoption of a soft punch through (SPT) concept as the vertical structure and an enhanced planar concept as the top structure, signed as SPT+ IGBT, the simulation results indicate the turn-off switching waveform of the 4500 V SPT+ IGBT is soft and also realizes an improved trade-off relationship between on-state voltage drop (Von) and turn-off loss (Eoff) in comparison with the SPT IGBT. Attention is also paid to the influences caused by different carrier stored layer doping dose on static and <span class="hlt">dynamic</span> performances, to <span class="hlt">optimize</span> on-state and switching losses of SPT+ IGBT. Project supported by the National Major Science and Technology Special Project of China (No. 2011ZX02504-002).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19920072551&hterms=Orbital+approach+orbital&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DOrbital%2Bapproach%2Borbital','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19920072551&hterms=Orbital+approach+orbital&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DOrbital%2Bapproach%2Borbital"><span id="translatedtitle">An inverse <span class="hlt">dynamics</span> approach to trajectory <span class="hlt">optimization</span> and guidance for an aerospace plane</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lu, Ping</p> <p>1992-01-01</p> <p>The <span class="hlt">optimal</span> ascent problem for an aerospace planes is formulated as an <span class="hlt">optimal</span> inverse <span class="hlt">dynamic</span> problem. Both minimum-fuel and minimax type of performance indices are considered. Some important features of the <span class="hlt">optimal</span> trajectory and controls are used to construct a nonlinear feedback midcourse controller, which not only greatly simplifies the difficult constrained <span class="hlt">optimization</span> problem and yields improved solutions, but is also suited for onboard implementation. Robust ascent guidance is obtained by using combination of feedback compensation and onboard generation of control through the inverse <span class="hlt">dynamics</span> approach. Accurate orbital insertion can be achieved with near-<span class="hlt">optimal</span> control of the rocket through inverse <span class="hlt">dynamics</span> even in the presence of disturbances.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AcAau.123...51H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AcAau.123...51H"><span id="translatedtitle">Campaign-level <span class="hlt">dynamic</span> network modelling for spaceflight logistics for the flexible path concept</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ho, Koki; de Weck, Olivier L.; Hoffman, Jeffrey A.; Shishko, Robert</p> <p>2016-06-01</p> <p>This paper develops a network <span class="hlt">optimization</span> formulation for <span class="hlt">dynamic</span> campaign-level space mission planning. Although many past space missions have been designed mainly from a mission-level perspective, a campaign-level perspective will be important for future space exploration. In order to find the <span class="hlt">optimal</span> campaign-level space transportation architecture, a <span class="hlt">mixed-integer</span> linear programming (MILP) formulation with a generalized multi-commodity flow and a time-expanded network is developed. Particularly, a new heuristics-based method, a partially static time-expanded network, is developed to provide a solution quickly. The developed method is applied to a case study containing human exploration of a near-Earth object (NEO) and Mars, related to the concept of the Flexible Path. The numerical results show that using the specific combinations of propulsion technologies, in-situ resource utilization (ISRU), and other space infrastructure elements can reduce the initial mass in low-Earth orbit (IMLEO) significantly. In addition, the case study results also show that we can achieve large IMLEO reduction by designing NEO and Mars missions together as a campaign compared with designing them separately owing to their common space infrastructure pre-deployment. This research will be an important step toward efficient and flexible campaign-level space mission planning.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009CMMPh..49..748B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009CMMPh..49..748B"><span id="translatedtitle"><span class="hlt">Optimal</span> control and <span class="hlt">optimal</span> trajectories of regional macroeconomic <span class="hlt">dynamics</span> based on the Pontryagin maximum principle</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bulgakov, V. K.; Strigunov, V. V.</p> <p>2009-05-01</p> <p>The Pontryagin maximum principle is used to prove a theorem concerning <span class="hlt">optimal</span> control in regional macroeconomics. A boundary value problem for <span class="hlt">optimal</span> trajectories of the state and adjoint variables is formulated, and <span class="hlt">optimal</span> curves are analyzed. An algorithm is proposed for solving the boundary value problem of <span class="hlt">optimal</span> control. The performance of the algorithm is demonstrated by computing an <span class="hlt">optimal</span> control and the corresponding <span class="hlt">optimal</span> trajectories.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23625909','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23625909"><span id="translatedtitle"><span class="hlt">Optimization</span> of conventional water treatment plant using <span class="hlt">dynamic</span> programming.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mostafa, Khezri Seyed; Bahareh, Ghafari; Elahe, Dadvar; Pegah, Dadras</p> <p>2015-12-01</p> <p>In this research, the mathematical models, indicating the capability of various units, such as rapid mixing, coagulation and flocculation, sedimentation, and the rapid sand filtration are used. Moreover, cost functions were used for the formulation of conventional water and wastewater treatment plant by applying Clark's formula (Clark, 1982). Also, by applying <span class="hlt">dynamic</span> programming algorithm, it is easy to design a conventional treatment system with minimal cost. The application of the model for a case reduced the annual cost. This reduction was approximately in the range of 4.5-9.5% considering variable limitations. Sensitivity analysis and prediction of system's feedbacks were performed for different alterations in proportion from parameters <span class="hlt">optimized</span> amounts. The results indicated (1) that the objective function is more sensitive to design flow rate (Q), (2) the variations in the alum dosage (A), and (3) the sand filter head loss (H). Increasing the inflow by 20%, the total annual cost would increase to about 12.6%, while 20% reduction in inflow leads to 15.2% decrease in the total annual cost. Similarly, 20% increase in alum dosage causes 7.1% increase in the total annual cost, while 20% decrease results in 7.9% decrease in the total annual cost. Furthermore, the pressure decrease causes 2.95 and 3.39% increase and decrease in total annual cost of treatment plants. PMID:23625909</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22763388','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22763388"><span id="translatedtitle">Function-valued adaptive <span class="hlt">dynamics</span> and <span class="hlt">optimal</span> control theory.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Parvinen, Kalle; Heino, Mikko; Dieckmann, Ulf</p> <p>2013-09-01</p> <p>In this article we further develop the theory of adaptive <span class="hlt">dynamics</span> of function-valued traits. Previous work has concentrated on models for which invasion fitness can be written as an integral in which the integrand for each argument value is a function of the strategy value at that argument value only. For this type of models of direct effect, singular strategies can be found using the calculus of variations, with singular strategies needing to satisfy Euler's equation with environmental feedback. In a broader, more mechanistically oriented class of models, the function-valued strategy affects a process described by differential equations, and fitness can be expressed as an integral in which the integrand for each argument value depends both on the strategy and on process variables at that argument value. In general, the calculus of variations cannot help analyzing this much broader class of models. Here we explain how to find singular strategies in this class of process-mediated models using <span class="hlt">optimal</span> control theory. In particular, we show that singular strategies need to satisfy Pontryagin's maximum principle with environmental feedback. We demonstrate the utility of this approach by studying the evolution of strategies determining seasonal flowering schedules. PMID:22763388</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3618714','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3618714"><span id="translatedtitle">Conceptualizing a Tool to <span class="hlt">Optimize</span> Therapy Based on <span class="hlt">Dynamic</span> Heterogeneity</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Liao, David; Estévez-Salmerón, Luis; Tlsty, Thea D.</p> <p>2012-01-01</p> <p>Complex biological systems often display a randomness paralleled in processes studied in fundamental physics. This simple stochasticity emerges owing to the complexity of the system and underlies a fundamental aspect of biology called phenotypic stochasticity. Ongoing stochastic fluctuations in phenotype at the single-unit level can contribute to two emergent population phenotypes. Phenotypic stochasticity not only generates heterogeneity within a cell population, but also allows reversible transitions back and forth between multiple states. This phenotypic interconversion tends to restore a population to a previous composition after that population has been depleted of specific members. We call this tendency homeostatic heterogeneity. These concepts of <span class="hlt">dynamic</span> heterogeneity can be applied to populations composed of molecules, cells, individuals, etc. Here we discuss the concept that phenotypic stochasticity both underlies the generation of heterogeneity within a cell population and can be used to control population composition, contributing, in particular, to both the ongoing emergence of drug resistance and an opportunity for depleting drug-resistant cells. Using notions of both “large” and “small” numbers of biomolecular components, we rationalize our use of Markov processes to model the generation and eradication of drug-resistant cells. Using these insights, we have developed a graphical tool, called a metronomogram, that we propose will allow us to <span class="hlt">optimize</span> dosing frequencies and total course durations for clinical benefit. PMID:23197078</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21115043','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21115043"><span id="translatedtitle"><span class="hlt">Optimal</span> spectral tracking--adapting to <span class="hlt">dynamic</span> regime change.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Brittain, John-Stuart; Halliday, David M</p> <p>2011-01-30</p> <p>Real world data do not always obey the statistical restraints imposed upon them by sophisticated analysis techniques. In spectral analysis for instance, an ergodic process--the interchangeability of temporal for spatial averaging--is assumed for a repeat-trial design. Many evolutionary scenarios, such as learning and motor consolidation, do not conform to such linear behaviour and should be approached from a more flexible perspective. To this end we previously introduced the method of <span class="hlt">optimal</span> spectral tracking (OST) in the study of trial-varying parameters. In this extension to our work we modify the OST routines to provide an adaptive implementation capable of reacting to <span class="hlt">dynamic</span> transitions in the underlying system state. In so doing, we generalise our approach to characterise both slow-varying and rapid fluctuations in time-series, simultaneously providing a metric of system stability. The approach is first applied to a surrogate dataset and compared to both our original non-adaptive solution and spectrogram approaches. The adaptive OST is seen to display fast convergence and desirable statistical properties. All three approaches are then applied to a neurophysiological recording obtained during a study on anaesthetic monitoring. Local field potentials acquired from the posterior hypothalamic region of a deep brain stimulation patient undergoing anaesthesia were analysed. The characterisation of features such as response delay, time-to-peak and modulation brevity are considered. PMID:21115043</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1022922','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1022922"><span id="translatedtitle">Photocathode <span class="hlt">Optimization</span> for a <span class="hlt">Dynamic</span> Transmission Electron Microscope: Final Report</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Ellis, P; Flom, Z; Heinselman, K; Nguyen, T; Tung, S; Haskell, R; Reed, B W; LaGrange, T</p> <p>2011-08-04</p> <p>The <span class="hlt">Dynamic</span> Transmission Electron Microscope (DTEM) team at Harvey Mudd College has been sponsored by LLNL to design and build a test setup for <span class="hlt">optimizing</span> the performance of the DTEM's electron source. Unlike a traditional TEM, the DTEM achieves much faster exposure times by using photoemission from a photocathode to produce electrons for imaging. The DTEM team's work is motivated by the need to improve the coherence and current density of the electron cloud produced by the electron gun in order to increase the image resolution and contrast achievable by DTEM. The photoemission test setup is nearly complete and the team will soon complete baseline tests of electron gun performance. The photoemission laser and high voltage power supply have been repaired; the optics path for relaying the laser to the photocathode has been finalized, assembled, and aligned; the internal setup of the vacuum chamber has been finalized and mostly implemented; and system control, synchronization, and data acquisition has been implemented in LabVIEW. Immediate future work includes determining a consistent alignment procedure to place the laser waist on the photocathode, and taking baseline performance measurements of the tantalum photocathode. Future research will examine the performance of the electron gun as a function of the photoemission laser profile, the photocathode material, and the geometry and voltages of the accelerating and focusing components in the electron gun. This report presents the team's progress and outlines the work that remains.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19820003437&hterms=branch+bound&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dbranch%2Bbound','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19820003437&hterms=branch+bound&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dbranch%2Bbound"><span id="translatedtitle">An <span class="hlt">optimization</span> model for energy generation and distribution in a <span class="hlt">dynamic</span> facility</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lansing, F. L.</p> <p>1981-01-01</p> <p>An analytical model is described using linear programming for the optimum generation and distribution of energy demands among competing energy resources and different economic criteria. The model, which will be used as a general engineering tool in the analysis of the Deep Space Network ground facility, considers several essential decisions for better design and operation. The decisions sought for the particular energy application include: the optimum time to build an assembly of elements, inclusion of a storage medium of some type, and the size or capacity of the elements that will minimize the total life-cycle cost over a given number of years. The model, which is structured in multiple time divisions, employ the decomposition principle for large-size matrices, the branch-and-bound method in <span class="hlt">mixed-integer</span> programming, and the revised simplex technique for efficient and economic computer use.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009LNCS.5745...74S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009LNCS.5745...74S"><span id="translatedtitle">Cost <span class="hlt">Optimization</span> Model for Business Applications in Virtualized Grid Environments</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Strebel, Jörg</p> <p></p> <p>The advent of Grid computing gives enterprises an ever increasing choice of computing options, yet research has so far hardly addressed the problem of mixing the different computing options in a cost-minimal fashion. The following paper presents a comprehensive cost model and a <span class="hlt">mixed</span> <span class="hlt">integer</span> <span class="hlt">optimization</span> model which can be used to minimize the IT expenditures of an enterprise and help in decision-making when to outsource certain business software applications. A sample scenario is analyzed and promising cost savings are demonstrated. Possible applications of the model to future research questions are outlined.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21872384','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21872384"><span id="translatedtitle">A two-stage support-vector-regression <span class="hlt">optimization</span> model for municipal solid waste management - a case study of Beijing, China.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dai, C; Li, Y P; Huang, G H</p> <p>2011-12-01</p> <p>In this study, a two-stage support-vector-regression <span class="hlt">optimization</span> model (TSOM) is developed for the planning of municipal solid waste (MSW) management in the urban districts of Beijing, China. It represents a new effort to enhance the analysis accuracy in <span class="hlt">optimizing</span> the MSW management system through coupling the support-vector-regression (SVR) model with an interval-parameter <span class="hlt">mixed</span> <span class="hlt">integer</span> linear programming (IMILP). The developed TSOM can not only predict the city's future waste generation amount, but also reflect <span class="hlt">dynamic</span>, interactive, and uncertain characteristics of the MSW management system. Four kernel functions such as linear kernel, polynomial kernel, radial basis function, and multi-layer perception kernel are chosen based on three quantitative simulation performance criteria [i.e. prediction accuracy (PA), fitting accuracy (FA) and over all accuracy (OA)]. The SVR with polynomial kernel has accurate prediction performance for MSW generation rate, with all of the three quantitative simulation performance criteria being over 96%. Two cases are considered based on different waste management policies. The results are valuable for supporting the adjustment of the existing waste-allocation patterns to raise the city's waste diversion rate, as well as the capacity planning of waste management system to satisfy the city's increasing waste treatment/disposal demands. PMID:21872384</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/20405047','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/20405047"><span id="translatedtitle"><span class="hlt">Dynamic</span> regime marginal structural mean models for estimation of <span class="hlt">optimal</span> <span class="hlt">dynamic</span> treatment regimes, Part II: proofs of results.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Orellana, Liliana; Rotnitzky, Andrea; Robins, James M</p> <p>2010-01-01</p> <p>In this companion article to "<span class="hlt">Dynamic</span> Regime Marginal Structural Mean Models for Estimation of <span class="hlt">Optimal</span> <span class="hlt">Dynamic</span> Treatment Regimes, Part I: Main Content" [Orellana, Rotnitzky and Robins (2010), IJB, Vol. 6, Iss. 2, Art. 7] we present (i) proofs of the claims in that paper, (ii) a proposal for the computation of a confidence set for the <span class="hlt">optimal</span> index when this lies in a finite set, and (iii) an example to aid the interpretation of the positivity assumption. PMID:20405047</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhyA..416..157L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhyA..416..157L"><span id="translatedtitle">Evacuation <span class="hlt">dynamic</span> and exit <span class="hlt">optimization</span> of a supermarket based on particle swarm <span class="hlt">optimization</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Lin; Yu, Zhonghai; Chen, Yang</p> <p>2014-12-01</p> <p>A modified particle swarm <span class="hlt">optimization</span> algorithm is proposed in this paper to investigate the <span class="hlt">dynamic</span> of pedestrian evacuation from a fire in a public building-a supermarket with multiple exits and configurations of counters. Two distinctive evacuation behaviours featured by the shortest-path strategy and the following-up strategy are simulated in the model, accounting for different categories of age and sex of the pedestrians along with the impact of the fire, including gases, heat and smoke. To examine the relationship among the progress of the overall evacuation and the layout and configuration of the site, a series of simulations are conducted in various settings: without a fire and with a fire at different locations. Those experiments reveal a general pattern of two-phase evacuation, i.e., a steep section and a flat section, in addition to the impact of the presence of multiple exits on the evacuation along with the geographic locations of the exits. For the study site, our simulations indicated the deficiency of the configuration and the current layout of this site in the process of evacuation and verified the availability of proposed solutions to resolve the deficiency. More specifically, for improvement of the effectiveness of the evacuation from the site, adding an exit between Exit 6 and Exit 7 and expanding the corridor at the right side of Exit 7 would significantly reduce the evacuation time.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19900013716','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19900013716"><span id="translatedtitle">Application of numerical <span class="hlt">optimization</span> techniques to control system design for nonlinear <span class="hlt">dynamic</span> models of aircraft</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lan, C. Edward; Ge, Fuying</p> <p>1989-01-01</p> <p>Control system design for general nonlinear flight <span class="hlt">dynamic</span> models is considered through numerical simulation. The design is accomplished through a numerical <span class="hlt">optimizer</span> coupled with analysis of flight <span class="hlt">dynamic</span> equations. The general flight <span class="hlt">dynamic</span> equations are numerically integrated and <span class="hlt">dynamic</span> characteristics are then identified from the <span class="hlt">dynamic</span> response. The design variables are determined iteratively by the <span class="hlt">optimizer</span> to <span class="hlt">optimize</span> a prescribed objective function which is related to desired <span class="hlt">dynamic</span> characteristics. Generality of the method allows nonlinear effects to aerodynamics and <span class="hlt">dynamic</span> coupling to be considered in the design process. To demonstrate the method, nonlinear simulation models for an F-5A and an F-16 configurations are used to design dampers to satisfy specifications on flying qualities and control systems to prevent departure. The results indicate that the present method is simple in formulation and effective in satisfying the design objectives.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22386785','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22386785"><span id="translatedtitle">Metamodeling and the Critic-based approach to multi-level <span class="hlt">optimization</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Werbos, Ludmilla; Kozma, Robert; Silva-Lugo, Rodrigo; Pazienza, Giovanni E; Werbos, Paul J</p> <p>2012-08-01</p> <p>Large-scale networks with hundreds of thousands of variables and constraints are becoming more and more common in logistics, communications, and distribution domains. Traditionally, the utility functions defined on such networks are <span class="hlt">optimized</span> using some variation of Linear Programming, such as <span class="hlt">Mixed</span> <span class="hlt">Integer</span> Programming (MIP). Despite enormous progress both in hardware (multiprocessor systems and specialized processors) and software (Gurobi) we are reaching the limits of what these tools can handle in real time. Modern logistic problems, for example, call for expanding the problem both vertically (from one day up to several days) and horizontally (combining separate solution stages into an integrated model). The complexity of such integrated models calls for alternative methods of solution, such as Approximate <span class="hlt">Dynamic</span> Programming (ADP), which provide a further increase in the performance necessary for the daily operation. In this paper, we present the theoretical basis and related experiments for solving the multistage decision problems based on the results obtained for shorter periods, as building blocks for the models and the solution, via Critic-Model-Action cycles, where various types of neural networks are combined with traditional MIP models in a unified <span class="hlt">optimization</span> system. In this system architecture, fast and simple feed-forward networks are trained to reasonably initialize more complicated recurrent networks, which serve as approximators of the value function (Critic). The combination of interrelated neural networks and <span class="hlt">optimization</span> modules allows for multiple queries for the same system, providing flexibility and <span class="hlt">optimizing</span> performance for large-scale real-life problems. A MATLAB implementation of our solution procedure for a realistic set of data and constraints shows promising results, compared to the iterative MIP approach. PMID:22386785</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007PhDT.......134G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007PhDT.......134G"><span id="translatedtitle"><span class="hlt">Optimal</span> GENCO bidding strategy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gao, Feng</p> <p></p> <p>Electricity industries worldwide are undergoing a period of profound upheaval. The conventional vertically integrated mechanism is being replaced by a competitive market environment. Generation companies have incentives to apply novel technologies to lower production costs, for example: Combined Cycle units. Economic dispatch with Combined Cycle units becomes a non-convex <span class="hlt">optimization</span> problem, which is difficult if not impossible to solve by conventional methods. Several techniques are proposed here: <span class="hlt">Mixed</span> <span class="hlt">Integer</span> Linear Programming, a hybrid method, as well as Evolutionary Algorithms. Evolutionary Algorithms share a common mechanism, stochastic searching per generation. The stochastic property makes evolutionary algorithms robust and adaptive enough to solve a non-convex <span class="hlt">optimization</span> problem. This research implements GA, EP, and PS algorithms for economic dispatch with Combined Cycle units, and makes a comparison with classical <span class="hlt">Mixed</span> <span class="hlt">Integer</span> Linear Programming. The electricity market equilibrium model not only helps Independent System Operator/Regulator analyze market performance and market power, but also provides Market Participants the ability to build <span class="hlt">optimal</span> bidding strategies based on Microeconomics analysis. Supply Function Equilibrium (SFE) is attractive compared to traditional models. This research identifies a proper SFE model, which can be applied to a multiple period situation. The equilibrium condition using discrete time <span class="hlt">optimal</span> control is then developed for fuel resource constraints. Finally, the research discusses the issues of multiple equilibria and mixed strategies, which are caused by the transmission network. Additionally, an advantage of the proposed model for merchant transmission planning is discussed. A market simulator is a valuable training and evaluation tool to assist sellers, buyers, and regulators to understand market performance and make better decisions. A traditional <span class="hlt">optimization</span> model may not be enough to consider the distributed, large-scale, and complex energy market. This research compares the performance and searching paths of different artificial life techniques such as Genetic Algorithm (GA), Evolutionary Programming (EP), and Particle Swarm (PS), and look for a proper method to emulate Generation Companies' (GENCOs) bidding strategies. After deregulation, GENCOs face risk and uncertainty associated with the fast-changing market environment. A profit-based bidding decision support system is critical for GENCOs to keep a competitive position in the new environment. Most past research do not pay special attention to the piecewise staircase characteristic of generator offer curves. This research proposes an <span class="hlt">optimal</span> bidding strategy based on Parametric Linear Programming. The proposed algorithm is able to handle actual piecewise staircase energy offer curves. The proposed method is then extended to incorporate incomplete information based on Decision Analysis. Finally, the author develops an <span class="hlt">optimal</span> bidding tool (GenBidding) and applies it to the RTS96 test system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3948477','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3948477"><span id="translatedtitle">Operational <span class="hlt">Optimization</span> of Large-Scale Parallel-Unit SWRO Desalination Plant Using Differential Evolution Algorithm</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Wang, Xiaolong; Jiang, Aipeng; Jiangzhou, Shu; Li, Ping</p> <p>2014-01-01</p> <p>A large-scale parallel-unit seawater reverse osmosis desalination plant contains many reverse osmosis (RO) units. If the operating conditions change, these RO units will not work at the <span class="hlt">optimal</span> design points which are computed before the plant is built. The operational <span class="hlt">optimization</span> problem (OOP) of the plant is to find out a scheduling of operation to minimize the total running cost when the change happens. In this paper, the OOP is modelled as a <span class="hlt">mixed-integer</span> nonlinear programming problem. A two-stage differential evolution algorithm is proposed to solve this OOP. Experimental results show that the proposed method is satisfactory in solution quality. PMID:24701180</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhyA..450..403Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhyA..450..403Y"><span id="translatedtitle">The <span class="hlt">optimal</span> <span class="hlt">dynamic</span> immunization under a controlled heterogeneous node-based SIRS model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Lu-Xing; Draief, Moez; Yang, Xiaofan</p> <p>2016-05-01</p> <p><span class="hlt">Dynamic</span> immunizations, under which the state of the propagation network of electronic viruses can be changed by adjusting the control measures, are regarded as an alternative to static immunizations. This paper addresses the <span class="hlt">optimal</span> <span class="hlt">dynamical</span> immunization under the widely accepted SIRS assumption. First, based on a controlled heterogeneous node-based SIRS model, an <span class="hlt">optimal</span> control problem capturing the <span class="hlt">optimal</span> <span class="hlt">dynamical</span> immunization is formulated. Second, the existence of an <span class="hlt">optimal</span> <span class="hlt">dynamical</span> immunization scheme is shown, and the corresponding <span class="hlt">optimality</span> system is derived. Next, some numerical examples are given to show that an <span class="hlt">optimal</span> immunization strategy can be worked out by numerically solving the <span class="hlt">optimality</span> system, from which it is found that the network topology has a complex impact on the <span class="hlt">optimal</span> immunization strategy. Finally, the difference between a payoff and the minimum payoff is estimated in terms of the deviation of the corresponding immunization strategy from the <span class="hlt">optimal</span> immunization strategy. The proposed <span class="hlt">optimal</span> immunization scheme is justified, because it can achieve a low level of infections at a low cost.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_10 --> <div id="page_11" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="201"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AIPC.1410..296K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AIPC.1410..296K"><span id="translatedtitle"><span class="hlt">Optimal</span> <span class="hlt">Dynamic</span> Advertising Strategy Under Age-Specific Market Segmentation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Krastev, Vladimir</p> <p>2011-12-01</p> <p>We consider the model proposed by Faggian and Grosset for determining the advertising efforts and goodwill in the long run of a company under age segmentation of consumers. Reducing this model to <span class="hlt">optimal</span> control sub problems we find the <span class="hlt">optimal</span> advertising strategy and goodwill.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014ZNatA..69..225Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014ZNatA..69..225Z"><span id="translatedtitle"><span class="hlt">Optimal</span> Campaign Strategies in Fractional-Order Smoking <span class="hlt">Dynamics</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zeb, Anwar; Zaman, Gul; Jung, Il Hyo; Khan, Madad</p> <p>2014-06-01</p> <p>This paper deals with the <span class="hlt">optimal</span> control problem in the giving up smoking model of fractional order. For the eradication of smoking in a community, we introduce three control variables in the form of education campaign, anti-smoking gum, and anti-nicotive drugs/medicine in the proposed fractional order model. We discuss the necessary conditions for the <span class="hlt">optimality</span> of a general fractional <span class="hlt">optimal</span> control problem whose fractional derivative is described in the Caputo sense. In order to do this, we minimize the number of potential and occasional smokers and maximize the number of ex-smokers. We use Pontryagin's maximum principle to characterize the <span class="hlt">optimal</span> levels of the three controls. The resulting <span class="hlt">optimality</span> system is solved numerically by MATLAB.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JIEI...10...58S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JIEI...10...58S"><span id="translatedtitle">An archived multi-objective simulated annealing for a <span class="hlt">dynamic</span> cellular manufacturing system</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shirazi, Hossein; Kia, Reza; Javadian, Nikbakhsh; Tavakkoli-Moghaddam, Reza</p> <p>2014-05-01</p> <p>To design a group layout of a cellular manufacturing system (CMS) in a <span class="hlt">dynamic</span> environment, a multi-objective <span class="hlt">mixed-integer</span> non-linear programming model is developed. The model integrates cell formation, group layout and production planning (PP) as three interrelated decisions involved in the design of a CMS. This paper provides an extensive coverage of important manufacturing features used in the design of CMSs and enhances the flexibility of an existing model in handling the fluctuations of part demands more economically by adding machine depot and PP decisions. Two conflicting objectives to be minimized are the total costs and the imbalance of workload among cells. As the considered objectives in this model are in conflict with each other, an archived multi-objective simulated annealing (AMOSA) algorithm is designed to find Pareto-<span class="hlt">optimal</span> solutions. Matrix-based solution representation, a heuristic procedure generating an initial and feasible solution and efficient mutation operators are the advantages of the designed AMOSA. To demonstrate the efficiency of the proposed algorithm, the performance of AMOSA is compared with an exact algorithm (i.e., ∈-constraint method) solved by the GAMS software and a well-known evolutionary algorithm, namely NSGA-II for some randomly generated problems based on some comparison metrics. The obtained results show that the designed AMOSA can obtain satisfactory solutions for the multi-objective model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PMB....58.5783K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PMB....58.5783K"><span id="translatedtitle"><span class="hlt">Optimized</span> <span class="hlt">dynamic</span> framing for PET-based myocardial blood flow estimation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kolthammer, Jeffrey A.; Muzic, Raymond F.</p> <p>2013-08-01</p> <p>An <span class="hlt">optimal</span> experiment design methodology was developed to select the framing schedule to be used in <span class="hlt">dynamic</span> positron emission tomography (PET) for estimation of myocardial blood flow using 82Rb. A compartment model and an arterial input function based on measured data were used to calculate a D-<span class="hlt">optimality</span> criterion for a wide range of candidate framing schedules. To validate the <span class="hlt">optimality</span> calculation, noisy time-activity curves were simulated, from which parameter values were estimated using an efficient and robust decomposition of the estimation problem. D-<span class="hlt">optimized</span> schedules improved estimate precision compared to non-<span class="hlt">optimized</span> schedules, including previously published schedules. To assess robustness, a range of physiologic conditions were simulated. Schedules that were <span class="hlt">optimal</span> for one condition were nearly-<span class="hlt">optimal</span> for others. The effect of infusion duration was investigated. <span class="hlt">Optimality</span> was better for shorter than for longer tracer infusion durations, with the <span class="hlt">optimal</span> schedule for the shortest infusion duration being nearly <span class="hlt">optimal</span> for other durations. Together this suggests that a framing schedule <span class="hlt">optimized</span> for one set of conditions will also work well for others and it is not necessary to use different schedules for different infusion durations or for rest and stress studies. The method for <span class="hlt">optimizing</span> schedules is general and could be applied in other <span class="hlt">dynamic</span> PET imaging studies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19900026871&hterms=distributed+file+systems&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Ddistributed%2Bfile%2Bsystems','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19900026871&hterms=distributed+file+systems&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Ddistributed%2Bfile%2Bsystems"><span id="translatedtitle"><span class="hlt">Optimal</span> <span class="hlt">dynamic</span> control of resources in a distributed system</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shin, Kang G.; Krishna, C. M.; Lee, Yann-Hang</p> <p>1989-01-01</p> <p>The authors quantitatively formulate the problem of controlling resources in a distributed system so as to <span class="hlt">optimize</span> a reward function and derive <span class="hlt">optimal</span> control strategies using Markov decision theory. The control variables treated are quite general; they could be control decisions related to system configuration, repair, diagnostics, files, or data. Two algorithms for resource control in distributed systems are derived for time-invariant and periodic environments, respectively. A detailed example to demonstrate the power and usefulness of the approach is provided.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/588945','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/588945"><span id="translatedtitle">Incorporation of inexact <span class="hlt">dynamic</span> <span class="hlt">optimization</span> with fuzzy relation analysis for integrated climate change impact study</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Huang, G.H.; Cohen, S.J.; Yin, Y.Y.; Bass, B.</p> <p>1996-09-01</p> <p>A climatic change impact assessment was performed for agricultural and timbering activities. An inexact <span class="hlt">dynamic</span> <span class="hlt">optimization</span> model was utilized that can reflect complex system features and a related fuzzy system relation analysis method for comprehensive impact patterns assessment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1043862','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1043862"><span id="translatedtitle"><span class="hlt">Optimization</span> of the <span class="hlt">Dynamic</span> Aperture for SPEAR3 Low-Emittance Upgrade</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wang, Lanfa; Huang, Xiaobiao; Nosochkov, Yuri; Safranek, James A.; Borland, Michael; /Argonne</p> <p>2012-05-30</p> <p>A low emittance upgrade is planned for SPEAR3. As the first phase, the emittance is reduced from 10nm to 7nm without additional magnets. A further upgrade with even lower emittance will require a damping wiggler. There is a smaller <span class="hlt">dynamic</span> aperture for the lower emittance optics due to a stronger nonlinearity. Elegant based Multi-Objective Genetic Algorithm (MOGA) is used to maximize the <span class="hlt">dynamic</span> aperture. Both the <span class="hlt">dynamic</span> aperture and beam lifetime are <span class="hlt">optimized</span> simultaneously. Various configurations of the sextupole magnets have been studied in order to find the best configuration. The betatron tune also can be <span class="hlt">optimized</span> to minimize resonance effects. The <span class="hlt">optimized</span> <span class="hlt">dynamic</span> aperture increases more than 15% from the nominal case and the lifetime increases from 14 hours to 17 hours. It is important that the increase of the <span class="hlt">dynamic</span> aperture is mainly in the beam injection direction. Therefore the injection efficiency will benefit from this improvement.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26117286','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26117286"><span id="translatedtitle">Fast engineering <span class="hlt">optimization</span>: A novel highly effective control parameterization approach for industrial <span class="hlt">dynamic</span> processes.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liu, Ping; Li, Guodong; Liu, Xinggao</p> <p>2015-09-01</p> <p>Control vector parameterization (CVP) is an important approach of the engineering <span class="hlt">optimization</span> for the industrial <span class="hlt">dynamic</span> processes. However, its major defect, the low <span class="hlt">optimization</span> efficiency caused by calculating the relevant differential equations in the generated nonlinear programming (NLP) problem repeatedly, limits its wide application in the engineering <span class="hlt">optimization</span> for the industrial <span class="hlt">dynamic</span> processes. A novel highly effective control parameterization approach, fast-CVP, is first proposed to improve the <span class="hlt">optimization</span> efficiency for industrial <span class="hlt">dynamic</span> processes, where the costate gradient formulae is employed and a fast approximate scheme is presented to solve the differential equations in <span class="hlt">dynamic</span> process simulation. Three well-known engineering <span class="hlt">optimization</span> benchmark problems of the industrial <span class="hlt">dynamic</span> processes are demonstrated as illustration. The research results show that the proposed fast approach achieves a fine performance that at least 90% of the computation time can be saved in contrast to the traditional CVP method, which reveals the effectiveness of the proposed fast engineering <span class="hlt">optimization</span> approach for the industrial <span class="hlt">dynamic</span> processes. PMID:26117286</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930004117','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930004117"><span id="translatedtitle">An inverse <span class="hlt">dynamics</span> approach to trajectory <span class="hlt">optimization</span> for an aerospace plane</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lu, Ping</p> <p>1992-01-01</p> <p>An inverse <span class="hlt">dynamics</span> approach for trajectory <span class="hlt">optimization</span> is proposed. This technique can be useful in many difficult trajectory <span class="hlt">optimization</span> and control problems. The application of the approach is exemplified by ascent trajectory <span class="hlt">optimization</span> for an aerospace plane. Both minimum-fuel and minimax types of performance indices are considered. When rocket augmentation is available for ascent, it is shown that accurate orbital insertion can be achieved through the inverse control of the rocket in the presence of disturbances.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhRvA..92f2106G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhRvA..92f2106G"><span id="translatedtitle">Time-limited <span class="hlt">optimal</span> <span class="hlt">dynamics</span> beyond the quantum speed limit</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gajdacz, Miroslav; Das, Kunal K.; Arlt, Jan; Sherson, Jacob F.; Opatrný, Tomáš</p> <p>2015-12-01</p> <p>The quantum speed limit sets the minimum time required to transfer a quantum system completely into a given target state. At shorter times the higher operation speed results in a loss of fidelity. Here we quantify the trade-off between the fidelity and the duration in a system driven by a time-varying control. The problem is addressed in the framework of Hilbert space geometry offering an intuitive interpretation of <span class="hlt">optimal</span> control algorithms. This approach leads to a necessary criterion for control <span class="hlt">optimality</span> applicable as a measure of algorithm convergence. The time fidelity trade-off expressed in terms of the direct Hilbert velocity provides a robust prediction of the quantum speed limit and allows one to adapt the control <span class="hlt">optimization</span> such that it yields a predefined fidelity. The results are verified numerically in a multilevel system with a constrained Hamiltonian and a classification scheme for the control sequences is proposed based on their optimizability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23400151','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23400151"><span id="translatedtitle">Performance <span class="hlt">optimization</span> of web-based medical simulation.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Halic, Tansel; Ahn, Woojin; De, Suvranu</p> <p>2013-01-01</p> <p>This paper presents a technique for performance <span class="hlt">optimization</span> of multimodal interactive web-based medical simulation. A web-based simulation framework is promising for easy access and wide dissemination of medical simulation. However, the real-time performance of the simulation highly depends on hardware capability on the client side. Providing consistent simulation in different hardware is critical for reliable medical simulation. This paper proposes a non-linear <span class="hlt">mixed</span> <span class="hlt">integer</span> programming model to <span class="hlt">optimize</span> the performance of visualization and physics computation while considering hardware capability and application specific constraints. The <span class="hlt">optimization</span> model identifies and parameterizes the rendering and computing capabilities of the client hardware using an exploratory proxy code. The parameters are utilized to determine the <span class="hlt">optimized</span> simulation conditions including texture sizes, mesh sizes and canvas resolution. The test results show that the <span class="hlt">optimization</span> model not only achieves a desired frame per second but also resolves visual artifacts due to low performance hardware. PMID:23400151</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/ED502608.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/ED502608.pdf"><span id="translatedtitle">Was Your Glass Left Half Full? Family <span class="hlt">Dynamics</span> and <span class="hlt">Optimism</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Buri, John R.; Gunty, Amy</p> <p>2008-01-01</p> <p>Students' levels of a frequently studied adaptive schema (<span class="hlt">optimism</span>) as a function of parenting variables (parental authority, family intrusiveness, parental overprotection, parentification, parental psychological control, and parental nurturance) were investigated. Results revealed that positive parenting styles were positively related to the…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhFl...28a5113Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhFl...28a5113Y"><span id="translatedtitle"><span class="hlt">Dynamic</span> <span class="hlt">optimization</span> methodology based on subgrid-scale dissipation for large eddy simulation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yu, Changping; Xiao, Zuoli; Li, Xinliang</p> <p>2016-01-01</p> <p>A <span class="hlt">dynamic</span> procedure based on subgrid-scale dissipation is proposed for large eddy simulation of turbulent flows. In the new method, the model coefficients are determined by minimizing the square error of the resolved dissipation rate based on the Germano identity. A <span class="hlt">dynamic</span> two-term mixed model is tested and evaluated both a priori and a posteriori in simulations of homogeneous and isotropic turbulence. The new <span class="hlt">dynamic</span> procedure proves to be more effective to <span class="hlt">optimize</span> the model coefficients as compared with traditional method. The corresponding <span class="hlt">dynamic</span> mixed model can predict the physical quantities more accurately than traditional <span class="hlt">dynamic</span> mixed model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1055043','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1055043"><span id="translatedtitle">INDDGO: Integrated Network Decomposition & <span class="hlt">Dynamic</span> programming for Graph <span class="hlt">Optimization</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Groer, Christopher S; Sullivan, Blair D; Weerapurage, Dinesh P</p> <p>2012-10-01</p> <p>It is well-known that <span class="hlt">dynamic</span> programming algorithms can utilize tree decompositions to provide a way to solve some \\emph{NP}-hard problems on graphs where the complexity is polynomial in the number of nodes and edges in the graph, but exponential in the width of the underlying tree decomposition. However, there has been relatively little computational work done to determine the practical utility of such <span class="hlt">dynamic</span> programming algorithms. We have developed software to construct tree decompositions using various heuristics and have created a fast, memory-efficient <span class="hlt">dynamic</span> programming implementation for solving maximum weighted independent set. We describe our software and the algorithms we have implemented, focusing on memory saving techniques for the <span class="hlt">dynamic</span> programming. We compare the running time and memory usage of our implementation with other techniques for solving maximum weighted independent set, including a commercial integer programming solver and a semi-definite programming solver. Our results indicate that it is possible to solve some instances where the underlying decomposition has width much larger than suggested by the literature. For certain types of problems, our <span class="hlt">dynamic</span> programming code runs several times faster than these other methods.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26526039','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26526039"><span id="translatedtitle">Computational Fluid <span class="hlt">Dynamics</span>-Based Design <span class="hlt">Optimization</span> Method for Archimedes Screw Blood Pumps.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yu, Hai; Janiga, Gábor; Thévenin, Dominique</p> <p>2016-04-01</p> <p>An <span class="hlt">optimization</span> method suitable for improving the performance of Archimedes screw axial rotary blood pumps is described in the present article. In order to achieve a more robust design and to save computational resources, this method combines the advantages of the established pump design theory with modern computer-aided, computational fluid <span class="hlt">dynamics</span> (CFD)-based design <span class="hlt">optimization</span> (CFD-O) relying on evolutionary algorithms and computational fluid <span class="hlt">dynamics</span>. The main purposes of this project are to: (i) integrate pump design theory within the already existing CFD-based <span class="hlt">optimization</span>; (ii) demonstrate that the resulting procedure is suitable for <span class="hlt">optimizing</span> an Archimedes screw blood pump in terms of efficiency. Results obtained in this study demonstrate that the developed tool is able to meet both objectives. Finally, the resulting level of hemolysis can be numerically assessed for the <span class="hlt">optimal</span> design, as hemolysis is an issue of overwhelming importance for blood pumps. PMID:26526039</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19940029394','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19940029394"><span id="translatedtitle">Multilevel decomposition approach to integrated aerodynamic/<span class="hlt">dynamic</span>/structural <span class="hlt">optimization</span> of helicopter rotor blades</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Walsh, Joanne L.; Young, Katherine C.; Pritchard, Jocelyn I.; Adelman, Howard M.; Mantay, Wayne R.</p> <p>1994-01-01</p> <p>This paper describes an integrated aerodynamic, <span class="hlt">dynamic</span>, and structural (IADS) <span class="hlt">optimization</span> procedure for helicopter rotor blades. The procedure combines performance, <span class="hlt">dynamics</span>, and structural analyses with a general purpose <span class="hlt">optimizer</span> using multilevel decomposition techniques. At the upper level, the structure is defined in terms of local quantities (stiffnesses, mass, and average strains). At the lower level, the structure is defined in terms of local quantities (detailed dimensions of the blade structure and stresses). The IADS procedure provides an <span class="hlt">optimization</span> technique that is compatible with industrial design practices in which the aerodynamic and <span class="hlt">dynamic</span> design is performed at a global level and the structural design is carried out at a detailed level with considerable dialogue and compromise among the aerodynamic, <span class="hlt">dynamic</span>, and structural groups. The IADS procedure is demonstrated for several cases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19950016536','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19950016536"><span id="translatedtitle">Integrated aerodynamic/<span class="hlt">dynamic</span>/structural <span class="hlt">optimization</span> of helicopter rotor blades using multilevel decomposition</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Walsh, Joanne L.; Young, Katherine C.; Pritchard, Jocelyn I.; Adelman, Howard M.; Mantay, Wayne R.</p> <p>1995-01-01</p> <p>This paper describes an integrated aerodynamic/<span class="hlt">dynamic</span>/structural (IADS) <span class="hlt">optimization</span> procedure for helicopter rotor blades. The procedure combines performance, <span class="hlt">dynamics</span>, and structural analyses with a general-purpose <span class="hlt">optimizer</span> using multilevel decomposition techniques. At the upper level, the structure is defined in terms of global quantities (stiffness, mass, and average strains). At the lower level, the structure is defined in terms of local quantities (detailed dimensions of the blade structure and stresses). The IADS procedure provides an <span class="hlt">optimization</span> technique that is compatible with industrial design practices in which the aerodynamic and <span class="hlt">dynamic</span> designs are performed at a global level and the structural design is carried out at a detailed level with considerable dialog and compromise among the aerodynamic, <span class="hlt">dynamic</span>, and structural groups. The IADS procedure is demonstrated for several examples.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013E%26ES...16a2085A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013E%26ES...16a2085A"><span id="translatedtitle">System design <span class="hlt">optimization</span> for stand-alone photovoltaic systems sizing by using superstructure model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Azau, M. A. M.; Jaafar, S.; Samsudin, K.</p> <p>2013-06-01</p> <p>Although the photovoltaic (PV) systems have been increasingly installed as an alternative and renewable green power generation, the initial set up cost, maintenance cost and equipment mismatch are some of the key issues that slows down the installation in small household. This paper presents the design <span class="hlt">optimization</span> of stand-alone photovoltaic systems using superstructure model where all possible types of technology of the equipment are captured and life cycle cost analysis is formulated as a <span class="hlt">mixed</span> <span class="hlt">integer</span> programming (MIP). A model for investment planning of power generation and long-term decision model are developed in order to help the system engineer to build a cost effective system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26087504','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26087504"><span id="translatedtitle"><span class="hlt">Optimization</span> in Quaternion <span class="hlt">Dynamic</span> Systems: Gradient, Hessian, and Learning Algorithms.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Xu, Dongpo; Xia, Yili; Mandic, Danilo P</p> <p>2016-02-01</p> <p>The <span class="hlt">optimization</span> of real scalar functions of quaternion variables, such as the mean square error or array output power, underpins many practical applications. Solutions typically require the calculation of the gradient and Hessian. However, real functions of quaternion variables are essentially nonanalytic, which are prohibitive to the development of quaternion-valued learning systems. To address this issue, we propose new definitions of quaternion gradient and Hessian, based on the novel generalized Hamilton-real (GHR) calculus, thus making a possible efficient derivation of general <span class="hlt">optimization</span> algorithms directly in the quaternion field, rather than using the isomorphism with the real domain, as is current practice. In addition, unlike the existing quaternion gradients, the GHR calculus allows for the product and chain rule, and for a one-to-one correspondence of the novel quaternion gradient and Hessian with their real counterparts. Properties of the quaternion gradient and Hessian relevant to numerical applications are also introduced, opening a new avenue of research in quaternion <span class="hlt">optimization</span> and greatly simplified the derivations of learning algorithms. The proposed GHR calculus is shown to yield the same generic algorithm forms as the corresponding real- and complex-valued algorithms. Advantages of the proposed framework are illuminated over illustrative simulations in quaternion signal processing and neural networks. PMID:26087504</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SCPMA..59d5784P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SCPMA..59d5784P"><span id="translatedtitle">Research on the <span class="hlt">optimal</span> <span class="hlt">dynamical</span> systems of three-dimensional Navier-Stokes equations based on weighted residual</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Peng, NaiFu; Guan, Hui; Wu, ChuiJie</p> <p>2016-04-01</p> <p>In this paper, the theory of constructing <span class="hlt">optimal</span> <span class="hlt">dynamical</span> systems based on weighted residual presented by Wu & Sha is applied to three-dimensional Navier-Stokes equations, and the <span class="hlt">optimal</span> <span class="hlt">dynamical</span> system modeling equations are derived. Then the multiscale global <span class="hlt">optimization</span> method based on coarse graining analysis is presented, by which a set of approximate global <span class="hlt">optimal</span> bases is directly obtained from Navier-Stokes equations and the construction of <span class="hlt">optimal</span> <span class="hlt">dynamical</span> systems is realized. The <span class="hlt">optimal</span> bases show good properties, such as showing the physical properties of complex flows and the turbulent vortex structures, being intrinsic to real physical problem and <span class="hlt">dynamical</span> systems, and having scaling symmetry in mathematics, etc.. In conclusion, using fewer terms of <span class="hlt">optimal</span> bases will approach the exact solutions of Navier-Stokes equations, and the <span class="hlt">dynamical</span> systems based on them show the most <span class="hlt">optimal</span> behavior.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_11 --> <div id="page_12" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="221"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/19392259','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/19392259"><span id="translatedtitle">Concatenated control sequences based on <span class="hlt">optimized</span> <span class="hlt">dynamic</span> decoupling.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Uhrig, Gtz S</p> <p>2009-03-27</p> <p>Two recent developments in quantum control, concatenation and <span class="hlt">optimization</span> of pulse intervals, are combined to yield a strategy to suppress unwanted couplings in quantum systems to high order. Longitudinal relaxation and transverse dephasing can be suppressed so that systems with a small splitting between their energy levels can be kept isolated from their environment. The required number of pulses grows exponentially with the desired order but is only the square root of the number needed if only concatenation is used. An approximate scheme even brings the number down to polynomial growth. The approach is expected to be useful for quantum information and for high-precision nuclear magnetic resonance. PMID:19392259</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ChPhB..24l8401L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ChPhB..24l8401L"><span id="translatedtitle"><span class="hlt">Optimal</span> satisfaction degree in energy harvesting cognitive radio networks</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Zan; Liu, Bo-Yang; Si, Jiang-Bo; Zhou, Fu-Hui</p> <p>2015-12-01</p> <p>A cognitive radio (CR) network with energy harvesting (EH) is considered to improve both spectrum efficiency and energy efficiency. A hidden Markov model (HMM) is used to characterize the imperfect spectrum sensing process. In order to maximize the whole satisfaction degree (WSD) of the cognitive radio network, a tradeoff between the average throughput of the secondary user (SU) and the interference to the primary user (PU) is analyzed. We formulate the satisfaction degree <span class="hlt">optimization</span> problem as a <span class="hlt">mixed</span> <span class="hlt">integer</span> nonlinear programming (MINLP) problem. The satisfaction degree <span class="hlt">optimization</span> problem is solved by using differential evolution (DE) algorithm. The proposed <span class="hlt">optimization</span> problem allows the network to adaptively achieve the <span class="hlt">optimal</span> solution based on its required quality of service (Qos). Numerical results are given to verify our analysis. Project supported by the National Natural Science Foundation of China (Grant No. 61301179), the Doctorial Programs Foundation of the Ministry of Education of China (Grant No. 20110203110011), and the 111 Project (Grant No. B08038).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4407907','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4407907"><span id="translatedtitle">Bacterial Temporal <span class="hlt">Dynamics</span> Enable <span class="hlt">Optimal</span> Design of Antibiotic Treatment</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Meredith, Hannah R.; Lopatkin, Allison J.; Anderson, Deverick J.; You, Lingchong</p> <p>2015-01-01</p> <p>There is a critical need to better use existing antibiotics due to the urgent threat of antibiotic resistant bacteria coupled with the reduced effort in developing new antibiotics. β-lactam antibiotics represent one of the most commonly used classes of antibiotics to treat a broad spectrum of Gram-positive and -negative bacterial pathogens. However, the rise of extended spectrum β-lactamase (ESBL) producing bacteria has limited the use of β-lactams. Due to the concern of complex drug responses, many β-lactams are typically ruled out if ESBL-producing pathogens are detected, even if these pathogens test as susceptible to some β-lactams. Using quantitative modeling, we show that β-lactams could still effectively treat pathogens producing low or moderate levels of ESBLs when administered properly. We further develop a metric to guide the design of a dosing protocol to <span class="hlt">optimize</span> treatment efficiency for any antibiotic-pathogen combination. Ultimately, <span class="hlt">optimized</span> dosing protocols could allow reintroduction of a repertoire of first-line antibiotics with improved treatment outcomes and preserve last-resort antibiotics. PMID:25905796</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21969994','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21969994"><span id="translatedtitle"><span class="hlt">Dynamic</span> regime marginal structural mean models for estimation of <span class="hlt">optimal</span> <span class="hlt">dynamic</span> treatment regimes, Part I: main content.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Orellana, Liliana; Rotnitzky, Andrea; Robins, James M</p> <p>2010-01-01</p> <p><span class="hlt">Dynamic</span> treatment regimes are set rules for sequential decision making based on patient covariate history. Observational studies are well suited for the investigation of the effects of <span class="hlt">dynamic</span> treatment regimes because of the variability in treatment decisions found in them. This variability exists because different physicians make different decisions in the face of similar patient histories. In this article we describe an approach to estimate the <span class="hlt">optimal</span> <span class="hlt">dynamic</span> treatment regime among a set of enforceable regimes. This set is comprised by regimes defined by simple rules based on a subset of past information. The regimes in the set are indexed by a Euclidean vector. The <span class="hlt">optimal</span> regime is the one that maximizes the expected counterfactual utility over all regimes in the set. We discuss assumptions under which it is possible to identify the <span class="hlt">optimal</span> regime from observational longitudinal data. Murphy et al. (2001) developed efficient augmented inverse probability weighted estimators of the expected utility of one fixed regime. Our methods are based on an extension of the marginal structural mean model of Robins (1998, 1999) which incorporate the estimation ideas of Murphy et al. (2001). Our models, which we call <span class="hlt">dynamic</span> regime marginal structural mean models, are specially suitable for estimating the <span class="hlt">optimal</span> treatment regime in a moderately small class of enforceable regimes of interest. We consider both parametric and semiparametric <span class="hlt">dynamic</span> regime marginal structural models. We discuss locally efficient, double-robust estimation of the model parameters and of the index of the <span class="hlt">optimal</span> treatment regime in the set. In a companion paper in this issue of the journal we provide proofs of the main results. PMID:21969994</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3145186','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3145186"><span id="translatedtitle">Locusts use <span class="hlt">dynamic</span> thermoregulatory behaviour to <span class="hlt">optimize</span> nutritional outcomes</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Coggan, Nicole; Clissold, Fiona J.; Simpson, Stephen J.</p> <p>2011-01-01</p> <p>Because key nutritional processes differ in their thermal optima, ectotherms may use temperature selection to <span class="hlt">optimize</span> performance in changing nutritional environments. Such behaviour would be especially advantageous to small terrestrial animals, which have low thermal inertia and often have access to a wide range of environmental temperatures over small distances. Using the locust, Locusta migratoria, we have demonstrated a direct link between nutritional state and thermoregulatory behaviour. When faced with chronic restrictions to the supply of nutrients, locusts selected increasingly lower temperatures within a gradient, thereby maximizing nutrient use efficiency at the cost of slower growth. Over the shorter term, when locusts were unable to find a meal in the normal course of ad libitum feeding, they immediately adjusted their thermoregulatory behaviour, selecting a lower temperature at which assimilation efficiency was maximal. Thus, locusts use fine scale patterns of movement and temperature selection to adjust for reduced nutrient supply and thereby ameliorate associated life-history consequences. PMID:21288941</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21288941','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21288941"><span id="translatedtitle">Locusts use <span class="hlt">dynamic</span> thermoregulatory behaviour to <span class="hlt">optimize</span> nutritional outcomes.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Coggan, Nicole; Clissold, Fiona J; Simpson, Stephen J</p> <p>2011-09-22</p> <p>Because key nutritional processes differ in their thermal optima, ectotherms may use temperature selection to <span class="hlt">optimize</span> performance in changing nutritional environments. Such behaviour would be especially advantageous to small terrestrial animals, which have low thermal inertia and often have access to a wide range of environmental temperatures over small distances. Using the locust, Locusta migratoria, we have demonstrated a direct link between nutritional state and thermoregulatory behaviour. When faced with chronic restrictions to the supply of nutrients, locusts selected increasingly lower temperatures within a gradient, thereby maximizing nutrient use efficiency at the cost of slower growth. Over the shorter term, when locusts were unable to find a meal in the normal course of ad libitum feeding, they immediately adjusted their thermoregulatory behaviour, selecting a lower temperature at which assimilation efficiency was maximal. Thus, locusts use fine scale patterns of movement and temperature selection to adjust for reduced nutrient supply and thereby ameliorate associated life-history consequences. PMID:21288941</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20090025073','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20090025073"><span id="translatedtitle">Discrete Adjoint-Based Design <span class="hlt">Optimization</span> of Unsteady Turbulent Flows on <span class="hlt">Dynamic</span> Unstructured Grids</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nielsen, Eric J.; Diskin, Boris; Yamaleev, Nail K.</p> <p>2009-01-01</p> <p>An adjoint-based methodology for design <span class="hlt">optimization</span> of unsteady turbulent flows on <span class="hlt">dynamic</span> unstructured grids is described. The implementation relies on an existing unsteady three-dimensional unstructured grid solver capable of <span class="hlt">dynamic</span> mesh simulations and discrete adjoint capabilities previously developed for steady flows. The discrete equations for the primal and adjoint systems are presented for the backward-difference family of time-integration schemes on both static and <span class="hlt">dynamic</span> grids. The consistency of sensitivity derivatives is established via comparisons with complex-variable computations. The current work is believed to be the first verified implementation of an adjoint-based <span class="hlt">optimization</span> methodology for the true time-dependent formulation of the Navier-Stokes equations in a practical computational code. Large-scale shape <span class="hlt">optimizations</span> are demonstrated for turbulent flows over a tiltrotor geometry and a simulated aeroelastic motion of a fighter jet.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhyA..436..430Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhyA..436..430Z"><span id="translatedtitle">Multiobjective biogeography based <span class="hlt">optimization</span> algorithm with decomposition for community detection in <span class="hlt">dynamic</span> networks</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhou, Xu; Liu, Yanheng; Li, Bin; Sun, Geng</p> <p>2015-10-01</p> <p>Identifying community structures in static network misses the opportunity to capture the evolutionary patterns. So community detection in <span class="hlt">dynamic</span> network has attracted many researchers. In this paper, a multiobjective biogeography based <span class="hlt">optimization</span> algorithm with decomposition (MBBOD) is proposed to solve community detection problem in <span class="hlt">dynamic</span> networks. In the proposed algorithm, the decomposition mechanism is adopted to <span class="hlt">optimize</span> two evaluation objectives named modularity and normalized mutual information simultaneously, which measure the quality of the community partitions and temporal cost respectively. A novel sorting strategy for multiobjective biogeography based <span class="hlt">optimization</span> is presented for comparing quality of habitats to get species counts. In addition, problem-specific migration and mutation model are introduced to improve the effectiveness of the new algorithm. Experimental results both on synthetic and real networks demonstrate that our algorithm is effective and promising, and it can detect communities more accurately in <span class="hlt">dynamic</span> networks compared with DYNMOGA and FaceNet.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AcAau.110..266V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AcAau.110..266V"><span id="translatedtitle">Performance evaluation of the inverse <span class="hlt">dynamics</span> method for <span class="hlt">optimal</span> spacecraft reorientation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ventura, Jacopo; Romano, Marcello; Walter, Ulrich</p> <p>2015-05-01</p> <p>This paper investigates the application of the inverse <span class="hlt">dynamics</span> in the virtual domain method to Euler angles, quaternions, and modified Rodrigues parameters for rapid <span class="hlt">optimal</span> attitude trajectory generation for spacecraft reorientation maneuvers. The impact of the virtual domain and attitude representation is numerically investigated for both minimum time and minimum energy problems. Owing to the nature of the inverse <span class="hlt">dynamics</span> method, it yields sub-<span class="hlt">optimal</span> solutions for minimum time problems. Furthermore, the virtual domain improves the <span class="hlt">optimality</span> of the solution, but at the cost of more computational time. The attitude representation also affects solution quality and computational speed. For minimum energy problems, the <span class="hlt">optimal</span> solution can be obtained without the virtual domain with any considered attitude representation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24616625','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24616625"><span id="translatedtitle"><span class="hlt">Dynamic</span> multiobjective <span class="hlt">optimization</span> algorithm based on average distance linear prediction model.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Li, Zhiyong; Chen, Hengyong; Xie, Zhaoxin; Chen, Chao; Sallam, Ahmed</p> <p>2014-01-01</p> <p>Many real-world <span class="hlt">optimization</span> problems involve objectives, constraints, and parameters which constantly change with time. <span class="hlt">Optimization</span> in a changing environment is a challenging task, especially when multiple objectives are required to be <span class="hlt">optimized</span> simultaneously. Nowadays the common way to solve <span class="hlt">dynamic</span> multiobjective <span class="hlt">optimization</span> problems (DMOPs) is to utilize history information to guide future search, but there is no common successful method to solve different DMOPs. In this paper, we define a kind of <span class="hlt">dynamic</span> multiobjectives problem with translational Paretooptimal set (DMOP-TPS) and propose a new prediction model named ADLM for solving DMOP-TPS. We have tested and compared the proposed prediction model (ADLM) with three traditional prediction models on several classic DMOP-TPS test problems. The simulation results show that our proposed prediction model outperforms other prediction models for DMOP-TPS. PMID:24616625</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3926970','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3926970"><span id="translatedtitle"><span class="hlt">Dynamic</span> Multiobjective <span class="hlt">Optimization</span> Algorithm Based on Average Distance Linear Prediction Model</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Xie, Zhaoxin; Chen, Chao; Sallam, Ahmed</p> <p>2014-01-01</p> <p>Many real-world <span class="hlt">optimization</span> problems involve objectives, constraints, and parameters which constantly change with time. <span class="hlt">Optimization</span> in a changing environment is a challenging task, especially when multiple objectives are required to be <span class="hlt">optimized</span> simultaneously. Nowadays the common way to solve <span class="hlt">dynamic</span> multiobjective <span class="hlt">optimization</span> problems (DMOPs) is to utilize history information to guide future search, but there is no common successful method to solve different DMOPs. In this paper, we define a kind of <span class="hlt">dynamic</span> multiobjectives problem with translational Paretooptimal set (DMOP-TPS) and propose a new prediction model named ADLM for solving DMOP-TPS. We have tested and compared the proposed prediction model (ADLM) with three traditional prediction models on several classic DMOP-TPS test problems. The simulation results show that our proposed prediction model outperforms other prediction models for DMOP-TPS. PMID:24616625</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19920004820','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19920004820"><span id="translatedtitle">Integration of <span class="hlt">dynamic</span>, aerodynamic, and structural <span class="hlt">optimization</span> of helicopter rotor blades</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Peters, David A.</p> <p>1991-01-01</p> <p>Summarized here is the first six years of research into the integration of structural, <span class="hlt">dynamic</span>, and aerodynamic considerations in the design-<span class="hlt">optimization</span> process for rotor blades. Specifically discussed here is the application of design <span class="hlt">optimization</span> techniques for helicopter rotor blades. The reduction of vibratory shears and moments at the blade root, aeroelastic stability of the rotor, optimum airframe design, and an efficient procedure for calculating system sensitivities with respect to the design variables used are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19770055137&hterms=uncertainty+principle&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Duncertainty%2Bprinciple','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19770055137&hterms=uncertainty+principle&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Duncertainty%2Bprinciple"><span id="translatedtitle">The uncertainty threshold principle - Some fundamental limitations of <span class="hlt">optimal</span> decision making under <span class="hlt">dynamic</span> uncertainty</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Athans, M.; Ku, R.; Gershwin, S. B.</p> <p>1977-01-01</p> <p>This note shows that the <span class="hlt">optimal</span> control of <span class="hlt">dynamic</span> systems with uncertain parameters has certain limitations. In particular, by means of a simple scalar linear-quadratic <span class="hlt">optimal</span> control example, it is shown that the infinite horizon solution does not exist if the parameter uncertainty exceeds a certain quantifiable threshold; we call this the uncertainty threshold principle. The philosophical and design implications of this result are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19790071257&hterms=uncertainty+principle&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Duncertainty%2Bprinciple','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19790071257&hterms=uncertainty+principle&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Duncertainty%2Bprinciple"><span id="translatedtitle">The Uncertainty Threshold Principle: Some Fundamental Limitations of <span class="hlt">Optimal</span> Decision Making Under <span class="hlt">Dynamic</span> Uncertainity</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Athans, M.; Ku, R.; Gershwin, S. B.</p> <p>1977-01-01</p> <p>This note shows that the <span class="hlt">optimal</span> control of <span class="hlt">dynamic</span> systems with uncertain parameters has certain limitations. In particular, by means of a simple scalar linear-quadratic <span class="hlt">optimal</span> control example, it is shown that the infinite horizon solution does not exist if the parameter uncertainty exceeds a certain quantifiable threshold; we call this the uncertainty threshold principle. The philosophical and design implications of this result are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4707024','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4707024"><span id="translatedtitle">Modeling Illicit Drug Use <span class="hlt">Dynamics</span> and Its <span class="hlt">Optimal</span> Control Analysis</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2015-01-01</p> <p>The global burden of death and disability attributable to illicit drug use, remains a significant threat to public health for both developed and developing nations. This paper presents a new mathematical modeling framework to investigate the effects of illicit drug use in the community. In our model the transmission process is captured as a social “contact” process between the susceptible individuals and illicit drug users. We conduct both epidemic and endemic analysis, with a focus on the threshold <span class="hlt">dynamics</span> characterized by the basic reproduction number. Using our model, we present illustrative numerical results with a case study in Cape Town, Gauteng, Mpumalanga and Durban communities of South Africa. In addition, the basic model is extended to incorporate time dependent intervention strategies. PMID:26819625</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/891553','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/891553"><span id="translatedtitle"><span class="hlt">OPTIMIZING</span> THE <span class="hlt">DYNAMIC</span> APERTURE FOR TRIPLE BEND ACHROMATIC LATTICES.</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>KRAMER, S.L.; BENGTSSON, J.</p> <p>2006-06-26</p> <p>The Triple Bend Achromatic (TBA) lattice has the potential for lower natural emittance per period than the Double Bend Achromatic (DBA) lattice for high brightness light sources. However, the DBA has been chosen for 3rd generation light sources more often due to the higher number of undulator straight section available for a comparable emittance. The TBA has considerable flexibility in linear optics tuning while maintaining this emittance advantage. We have used the tune and chromaticity flexibility of a TBA lattice to minimize the lowest order nonlinearities to implement a 3rd order achromatic tune, while maintaining a constant emittance. This frees the geometric sextupoles to counter the higher order nonlinearities. This procedure is being used to improve the nonlinear <span class="hlt">dynamics</span> of the TBA as a proposed lattice for NSLS-II facility. The flexibility of the TBA lattice will also provide for future upgrade capabilities of the beam parameters.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27055729','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27055729"><span id="translatedtitle">Endocrine Flexibility: <span class="hlt">Optimizing</span> Phenotypes in a <span class="hlt">Dynamic</span> World?</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Taff, Conor C; Vitousek, Maren N</p> <p>2016-06-01</p> <p>Responding appropriately to changing conditions is crucial in <span class="hlt">dynamic</span> environments. Individual variation in the flexibility of physiological mediators of phenotype may influence the capacity to mount an integrated response to unpredictable changes in social or ecological context. We propose here a conceptual framework of rapid endocrine flexibility that integrates ecological endocrinology with theoretical and empirical studies of phenotypic plasticity and behavioral syndromes. We highlight the need for research addressing variation in the scope and speed of flexibility, and provide suggestions for future studies of these potentially evolving traits. Elucidating the causes and consequences of variation in endocrine flexibility may have important implications for the evolution of behavior, and for predicting the response of individuals and populations to rapidly changing environments. PMID:27055729</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1155060','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1155060"><span id="translatedtitle"><span class="hlt">Dynamical</span> Arrest, Structural Disorder, and <span class="hlt">Optimization</span> of Organic Photovoltaic Devices</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gould, Ian; Dmitry, Matyushov</p> <p>2014-09-11</p> <p>This project describes fundamental experimental and theoretical work that relates to charge separation and migration in the solid, heterogeneous or aggregated state. Marcus theory assumes a system in equilibrium with all possible solvent (dipolar) configurations, with rapid interconversion among these on the ET timescale. This project has addressed the more general situation where the medium is at least partially frozen on the ET timescale, i.e. under conditions of <span class="hlt">dynamical</span> arrest. The approach combined theory and experiment and includes: (1) Computer simulations of model systems, (2) Development of analytical procedures consistent with computer experiment and (3) Experimental studies and testing of the formal theories on this data. Electron transfer processes are unique as a consequence of the close connection between kinetics, spectroscopy and theory, which is an essential component of this work.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19900058102&hterms=linear+programming&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dlinear%2Bprogramming','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19900058102&hterms=linear+programming&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dlinear%2Bprogramming"><span id="translatedtitle"><span class="hlt">Optimal</span> input design for aircraft parameter estimation using <span class="hlt">dynamic</span> programming principles</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Klein, Vladislav; Morelli, Eugene A.</p> <p>1990-01-01</p> <p>A new technique was developed for designing <span class="hlt">optimal</span> flight test inputs for aircraft parameter estimation experiments. The principles of <span class="hlt">dynamic</span> programming were used for the design in the time domain. This approach made it possible to include realistic practical constraints on the input and output variables. A description of the new approach is presented, followed by an example for a multiple input linear model describing the lateral <span class="hlt">dynamics</span> of a fighter aircraft. The <span class="hlt">optimal</span> input designs produced by the new technique demonstrated improved quality and expanded capability relative to the conventional multiple input design method.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20090004433','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20090004433"><span id="translatedtitle"><span class="hlt">Optimal</span> Input Design for Aircraft Parameter Estimation using <span class="hlt">Dynamic</span> Programming Principles</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Morelli, Eugene A.; Klein, Vladislav</p> <p>1990-01-01</p> <p>A new technique was developed for designing <span class="hlt">optimal</span> flight test inputs for aircraft parameter estimation experiments. The principles of <span class="hlt">dynamic</span> programming were used for the design in the time domain. This approach made it possible to include realistic practical constraints on the input and output variables. A description of the new approach is presented, followed by an example for a multiple input linear model describing the lateral <span class="hlt">dynamics</span> of a fighter aircraft. The <span class="hlt">optimal</span> input designs produced by the new technique demonstrated improved quality and expanded capability relative to the conventional multiple input design method.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_12 --> <div id="page_13" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="241"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19770046002&hterms=uncertainty+principle&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Duncertainty%2Bprinciple','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19770046002&hterms=uncertainty+principle&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Duncertainty%2Bprinciple"><span id="translatedtitle">The uncertainty threshold principle - Fundamental limitations of <span class="hlt">optimal</span> decision making under <span class="hlt">dynamic</span> uncertainty</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Athans, M.; Ku, R.; Gershwin, S. B.</p> <p>1976-01-01</p> <p>The fundamental limitations of the <span class="hlt">optimal</span> control of <span class="hlt">dynamic</span> systems with random parameters are analyzed by studying a scalar linear-quadratic <span class="hlt">optimal</span> control example. It is demonstrated that optimum long-range decision making is possible only if the <span class="hlt">dynamic</span> uncertainty (quantified by the means and covariances of the random parameters) is below a certain threshold. If this threshold is exceeded, there do not exist optimum decision rules. This phenomenon is called the 'uncertainty threshold principle'. The implications of this phenomenon to the field of modelling, identification, and adaptive control are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AcAau.105..428H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AcAau.105..428H"><span id="translatedtitle"><span class="hlt">Dynamic</span> modeling and <span class="hlt">optimization</span> for space logistics using time-expanded networks</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ho, Koki; de Weck, Olivier L.; Hoffman, Jeffrey A.; Shishko, Robert</p> <p>2014-12-01</p> <p>This research develops a <span class="hlt">dynamic</span> logistics network formulation for lifecycle <span class="hlt">optimization</span> of mission sequences as a system-level integrated method to find an <span class="hlt">optimal</span> combination of technologies to be used at each stage of the campaign. This formulation can find the <span class="hlt">optimal</span> transportation architecture considering its technology trades over time. The proposed methodologies are inspired by the ground logistics analysis techniques based on linear programming network <span class="hlt">optimization</span>. Particularly, the time-expanded network and its extension are developed for <span class="hlt">dynamic</span> space logistics network <span class="hlt">optimization</span> trading the quality of the solution with the computational load. In this paper, the methodologies are applied to a human Mars exploration architecture design problem. The results reveal multiple <span class="hlt">dynamic</span> system-level trades over time and give recommendation of the <span class="hlt">optimal</span> strategy for the human Mars exploration architecture. The considered trades include those between In-Situ Resource Utilization (ISRU) and propulsion technologies as well as the orbit and depot location selections over time. This research serves as a precursor for eventual permanent settlement and colonization of other planets by humans and us becoming a multi-planet species.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011ApCM...18..539S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011ApCM...18..539S"><span id="translatedtitle"><span class="hlt">Dynamic</span> Stability <span class="hlt">Optimization</span> of Laminated Composite Plates under Combined Boundary Loading</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shafei, Erfan; Kabir, Mohammad Zaman</p> <p>2011-12-01</p> <p><span class="hlt">Dynamic</span> stability and design <span class="hlt">optimization</span> of laminated simply supported plates under planar conservative boundary loads are investigated in current study. Examples can be found in internal connecting elements of spacecraft and aerospace structures subjected to edge axial and shear loads. Designation of such elements is function of layup configuration, plate aspect ratio, loading combinations, and layup thickness. An optimum design aims maximum stability load satisfying a predefined stable vibration frequency. The interaction between compound loading and layup angle parameter affects the order of merging vibration modes and may stabilize the <span class="hlt">dynamic</span> response. Laminated plates are assumed to be angle-plies symmetric to mid-plane surface. <span class="hlt">Dynamic</span> equilibrium PDE has been solved using kernel integral transformation for modal frequency values and eigenvalue-based orthogonal functions for critical stability loads. The dictating <span class="hlt">dynamic</span> stability mode is shown to be controlled by geometric stiffness distributions of composite plates. Solution of presented design <span class="hlt">optimization</span> problem has been done using analytical approach combined with interior penalty multiplier algorithm. The results are verified by FEA approach and stability zones of original and <span class="hlt">optimized</span> plates are stated as final data. Presented method can help designers to stabilize the <span class="hlt">dynamic</span> response of composite plates by selecting an <span class="hlt">optimized</span> layup orientation and thickness for prescribed design circumstances.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25570695','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25570695"><span id="translatedtitle">An <span class="hlt">optimized</span> ultrasound digital beamformer with <span class="hlt">dynamic</span> focusing implemented on FPGA.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Almekkawy, Mohamed; Xu, Jingwei; Chirala, Mohan</p> <p>2014-01-01</p> <p>We present a resource-<span class="hlt">optimized</span> <span class="hlt">dynamic</span> digital beamformer for an ultrasound system based on a field-programmable gate array (FPGA). A comprehensive 64-channel receive beamformer with full <span class="hlt">dynamic</span> focusing is embedded in the Altera Arria V FPGA chip. To improve spatial and contrast resolution, full <span class="hlt">dynamic</span> beamforming is implemented by a novel method with resource <span class="hlt">optimization</span>. This was conceived using the implementation of the delay summation through a bulk (coarse) delay and fractional (fine) delay. The sampling frequency is 40 MHz and the beamformer includes a 240 MHz polyphase filter that enhances the temporal resolution of the system while relaxing the Analog-to-Digital converter (ADC) bandwidth requirement. The results indicate that our 64-channel <span class="hlt">dynamic</span> beamformer architecture is amenable for a low power FPGA-based implementation in a portable ultrasound system. PMID:25570695</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4807629','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4807629"><span id="translatedtitle">Numerical Simulation of a Tumor Growth <span class="hlt">Dynamics</span> Model Using Particle Swarm <span class="hlt">Optimization</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Wang, Zhijun; Wang, Qing</p> <p>2016-01-01</p> <p>Tumor cell growth models involve high-dimensional parameter spaces that require computationally tractable methods to solve. To address a proposed tumor growth <span class="hlt">dynamics</span> mathematical model, an instance of the particle swarm <span class="hlt">optimization</span> method was implemented to speed up the search process in the multi-dimensional parameter space to find <span class="hlt">optimal</span> parameter values that fit experimental data from mice cancel cells. The fitness function, which measures the difference between calculated results and experimental data, was minimized in the numerical simulation process. The results and search efficiency of the particle swarm <span class="hlt">optimization</span> method were compared to those from other evolutional methods such as genetic algorithms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/20447042','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/20447042"><span id="translatedtitle">Shape <span class="hlt">optimization</span> of the diffuser blade of an axial blood pump by computational fluid <span class="hlt">dynamics</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhu, Lailai; Zhang, Xiwen; Yao, Zhaohui</p> <p>2010-03-01</p> <p>Computational fluid <span class="hlt">dynamics</span> (CFD) has been a viable and effective way to predict hydraulic performance, flow field, and shear stress distribution within a blood pump. We developed an axial blood pump with CFD and carried out a CFD-based shape <span class="hlt">optimization</span> of the diffuser blade to enhance pressure output and diminish backflow in the impeller-diffuser connecting region at a fixed design point. Our <span class="hlt">optimization</span> combined a computer-aided design package, a mesh generator, and a CFD solver in an automation environment with process integration and <span class="hlt">optimization</span> software. A genetic <span class="hlt">optimization</span> algorithm was employed to find the pareto-<span class="hlt">optimal</span> designs from which we could make trade-off decisions. Finally, a set of representative designs was analyzed and compared on the basis of the energy equation. The role of the inlet angle of the diffuser blade was analyzed, accompanied by its relationship with pressure output and backflow in the impeller-diffuser connecting region. PMID:20447042</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19920004750','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19920004750"><span id="translatedtitle">A new method of <span class="hlt">optimal</span> design for a two-dimensional diffuser by using <span class="hlt">dynamic</span> programming</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gu, Chuangang; Zhang, Moujin; Chen, XI; Miao, Yongmiao</p> <p>1991-01-01</p> <p>A new method for predicting the <span class="hlt">optimal</span> velocity distribution on the wall of a two dimensional diffuser is presented. The method uses <span class="hlt">dynamic</span> programming to solve the <span class="hlt">optimal</span> control problem with inequality constraints of state variables. The physical model of <span class="hlt">optimization</span> is designed to prevent the separation of the boundary layer while approaching the maximum pressure ratio in a diffuser of a specified length. The computational results are in fair agreement with the experimental ones. <span class="hlt">Optimal</span> velocity distribution on a diffuser wall is said to occur when the flow decelerates quickly at first and then smoothly, while the flow is near separation, but always protected from it. The <span class="hlt">optimal</span> velocity distribution can be used to design the contour of the diffuser.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014SPIE.9072E..0EM','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014SPIE.9072E..0EM"><span id="translatedtitle"><span class="hlt">Optimizing</span> electromagnetic induction sensors for <span class="hlt">dynamic</span> munitions classification surveys</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Miller, Jonathan S.; Keranen, Joe; Schultz, Gregory</p> <p>2014-06-01</p> <p>Standard protocol for detection and classification of Unexploded Ordnance (UXO) comprises a two-step process that includes an initial digital geophysical mapping (DGM) survey to detect magnetic field anomalies followed by a cued survey at each anomaly location that enables classification of these anomalies. The initial DGM survey is typically performed using a low resolution single axis electromagnetic induction (EMI) sensor while the follow-up cued survey requires revisiting each anomaly location with a multi-axis high resolution EMI sensor. The DGM survey comprises data collection in tightly spaced transects over the entire survey area. Once data collection in this area is complete, a threshold analysis is applied to the resulting magnetic field anomaly map to identify anomalies corresponding to potential targets of interest (TOI). The cued sensor is deployed in static mode where this higher resolution sensor is placed over the location of each anomaly to record a number of soundings that may be stacked and averaged to produce low noise data. These data are of sufficient quality to subsequently classify the object as either TOI or clutter. While this approach has demonstrated success in producing effective classification of UXO, conducting successive surveys is time consuming. Additionally, the low resolution of the initial DGM survey often produces errors in the target picking process that results in poor placement of the cued sensor and often requires several revisits to the anomaly location to ensure adequate characterization of the target space. We present data and test results from an advanced multi-axis EMI sensor <span class="hlt">optimized</span> to provide both detection and classification from a single survey. We demonstrate how the large volume of data from this sensor may be used to produce effective detection and classification decisions while only requiring one survey of the munitions response area.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26810832','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26810832"><span id="translatedtitle">Investigating molecular <span class="hlt">dynamics</span>-guided lead <span class="hlt">optimization</span> of EGFR inhibitors.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lavecchia, Martin J; Puig de la Bellacasa, Raimon; Borrell, José I; Cavasotto, Claudio N</p> <p>2016-02-15</p> <p>The epidermal growth factor receptor (EGFR) is part of an extended family of proteins that together control aspects of cell growth and development, and thus a validated target for drug discovery. We explore in this work the suitability of a molecular <span class="hlt">dynamics</span>-based end-point binding free energy protocol to estimate the relative affinities of a virtual combinatorial library designed around the EGFR model inhibitor 6{1} as a tool to guide chemical synthesis toward the most promising compounds. To investigate the validity of this approach, selected analogs including some with better and worse predicted affinities relative to 6{1} were synthesized, and their biological activity determined. To understand the binding determinants of the different analogs, hydrogen bonding and van der Waals contributions, and water molecule bridging in the EGFR-analog complexes were analyzed. The experimental validation was in good qualitative agreement with our theoretical calculations, while also a 6-dibromophenyl-substituted compound with enhanced inhibitory effect on EGFR compared to the reference ligand was obtained. PMID:26810832</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014APS..MARS15014M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014APS..MARS15014M"><span id="translatedtitle">Stokesian <span class="hlt">dynamics</span> <span class="hlt">optimization</span> of three linked spheres microswimmers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Marconi, V. I.; Berdakin, I.; Banchio, A. J.</p> <p>2014-03-01</p> <p>Self-propulsion of swimmers is only possible due to motility strategies able to overcome the absence of inertia. Only the swimming strategies that are time-irreversible are successful. One of the simplest swimmers fulfilling this requirement is the three-linked-spheres swimmer, TLS, a toy model swimmer built upon three spheres linked by two arms that contracts asynchronously. This TLS has received significant attention because it can be studied both, analytically and numerically. Using stokesian <span class="hlt">dynamics</span> we investigate in detail the net displacement, velocities, forces and power consumption. We compare two swimming strategies: square and circular phase-space cycles. If the efficiency is defined as the ratio between power dissipation and the work needed to produce the same motion by an external force, we show that the most efficient swimmer is the one with almost maximum (maximum) arms contraction for square (circular) cycles. Interestingly, under these optimum conditions, the analytical predictions based on point force approximations of the hydrodynamic mobility tensor differ significantly from those found in our more accurate simulations. This fact highlights the importance of a proper treatment of the hydrodynamic interactions. Supported by CONICET and SeCyt-UNC, Cordoba, Argentina, and NSF(USA)-CONICET(Argentina).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24982962','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24982962"><span id="translatedtitle">Fuzzy mixed assembly line sequencing and scheduling <span class="hlt">optimization</span> model using multiobjective <span class="hlt">dynamic</span> fuzzy GA.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tahriri, Farzad; Dawal, Siti Zawiah Md; Taha, Zahari</p> <p>2014-01-01</p> <p>A new multiobjective <span class="hlt">dynamic</span> fuzzy genetic algorithm is applied to solve a fuzzy mixed-model assembly line sequencing problem in which the primary goals are to minimize the total make-span and minimize the setup number simultaneously. Trapezoidal fuzzy numbers are implemented for variables such as operation and travelling time in order to generate results with higher accuracy and representative of real-case data. An improved genetic algorithm called fuzzy adaptive genetic algorithm (FAGA) is proposed in order to solve this <span class="hlt">optimization</span> model. In establishing the FAGA, five <span class="hlt">dynamic</span> fuzzy parameter controllers are devised in which fuzzy expert experience controller (FEEC) is integrated with automatic learning <span class="hlt">dynamic</span> fuzzy controller (ALDFC) technique. The enhanced algorithm <span class="hlt">dynamically</span> adjusts the population size, number of generations, tournament candidate, crossover rate, and mutation rate compared with using fixed control parameters. The main idea is to improve the performance and effectiveness of existing GAs by <span class="hlt">dynamic</span> adjustment and control of the five parameters. Verification and validation of the <span class="hlt">dynamic</span> fuzzy GA are carried out by developing test-beds and testing using a multiobjective fuzzy mixed production assembly line sequencing <span class="hlt">optimization</span> problem. The simulation results highlight that the performance and efficacy of the proposed novel <span class="hlt">optimization</span> algorithm are more efficient than the performance of the standard genetic algorithm in mixed assembly line sequencing model. PMID:24982962</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JHyd..529..928J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JHyd..529..928J"><span id="translatedtitle">Credibility theory based <span class="hlt">dynamic</span> control bound <span class="hlt">optimization</span> for reservoir flood limited water level</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jiang, Zhiqiang; Sun, Ping; Ji, Changming; Zhou, Jianzhong</p> <p>2015-10-01</p> <p>The <span class="hlt">dynamic</span> control operation of reservoir flood limited water level (FLWL) can solve the contradictions between reservoir flood control and beneficial operation well, and it is an important measure to make sure the security of flood control and realize the flood utilization. The <span class="hlt">dynamic</span> control bound of FLWL is a fundamental key element for implementing reservoir <span class="hlt">dynamic</span> control operation. In order to <span class="hlt">optimize</span> the <span class="hlt">dynamic</span> control bound of FLWL by considering flood forecasting error, this paper took the forecasting error as a fuzzy variable, and described it with the emerging credibility theory in recent years. By combining the flood forecasting error quantitative model, a credibility-based fuzzy chance constrained model used to <span class="hlt">optimize</span> the <span class="hlt">dynamic</span> control bound was proposed in this paper, and fuzzy simulation technology was used to solve the model. The FENGTAN reservoir in China was selected as a case study, and the results show that, compared with the original operation water level, the initial operation water level (IOWL) of FENGTAN reservoir can be raised 4 m, 2 m and 5.5 m respectively in the three division stages of flood season, and without increasing flood control risk. In addition, the rationality and feasibility of the proposed forecasting error quantitative model and credibility-based <span class="hlt">dynamic</span> control bound <span class="hlt">optimization</span> model are verified by the calculation results of extreme risk theory.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3985312','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3985312"><span id="translatedtitle">Fuzzy Mixed Assembly Line Sequencing and Scheduling <span class="hlt">Optimization</span> Model Using Multiobjective <span class="hlt">Dynamic</span> Fuzzy GA</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Tahriri, Farzad; Dawal, Siti Zawiah Md; Taha, Zahari</p> <p>2014-01-01</p> <p>A new multiobjective <span class="hlt">dynamic</span> fuzzy genetic algorithm is applied to solve a fuzzy mixed-model assembly line sequencing problem in which the primary goals are to minimize the total make-span and minimize the setup number simultaneously. Trapezoidal fuzzy numbers are implemented for variables such as operation and travelling time in order to generate results with higher accuracy and representative of real-case data. An improved genetic algorithm called fuzzy adaptive genetic algorithm (FAGA) is proposed in order to solve this <span class="hlt">optimization</span> model. In establishing the FAGA, five <span class="hlt">dynamic</span> fuzzy parameter controllers are devised in which fuzzy expert experience controller (FEEC) is integrated with automatic learning <span class="hlt">dynamic</span> fuzzy controller (ALDFC) technique. The enhanced algorithm <span class="hlt">dynamically</span> adjusts the population size, number of generations, tournament candidate, crossover rate, and mutation rate compared with using fixed control parameters. The main idea is to improve the performance and effectiveness of existing GAs by <span class="hlt">dynamic</span> adjustment and control of the five parameters. Verification and validation of the <span class="hlt">dynamic</span> fuzzy GA are carried out by developing test-beds and testing using a multiobjective fuzzy mixed production assembly line sequencing <span class="hlt">optimization</span> problem. The simulation results highlight that the performance and efficacy of the proposed novel <span class="hlt">optimization</span> algorithm are more efficient than the performance of the standard genetic algorithm in mixed assembly line sequencing model. PMID:24982962</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/413438','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/413438"><span id="translatedtitle">Synthesizing <span class="hlt">optimal</span> waste blends</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Narayan, V.; Diwekar, W.M.; Hoza, M.</p> <p>1996-10-01</p> <p>Vitrification of tank wastes to form glass is a technique that will be used for the disposal of high-level waste at Hanford. Process and storage economics show that minimizing the total number of glass logs produced is the key to keeping cost as low as possible. The amount of glass produced can be reduced by blending of the wastes. The <span class="hlt">optimal</span> way to combine the tanks to minimize the vole of glass can be determined from a discrete blend calculation. However, this problem results in a combinatorial explosion as the number of tanks increases. Moreover, the property constraints make this problem highly nonconvex where many algorithms get trapped in local minima. In this paper the authors examine the use of different combinatorial <span class="hlt">optimization</span> approaches to solve this problem. A two-stage approach using a combination of simulated annealing and nonlinear programming (NLP) is developed. The results of different methods such as the heuristics approach based on human knowledge and judgment, the <span class="hlt">mixed</span> <span class="hlt">integer</span> nonlinear programming (MINLP) approach with GAMS, and branch and bound with lower bound derived from the structure of the given blending problem are compared with this coupled simulated annealing and NLP approach.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3532319','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3532319"><span id="translatedtitle"><span class="hlt">Dynamic</span> <span class="hlt">optimization</span> of distributed biological systems using robust and efficient numerical techniques</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2012-01-01</p> <p>Background Systems biology allows the analysis of biological systems behavior under different conditions through in silico experimentation. The possibility of perturbing biological systems in different manners calls for the design of perturbations to achieve particular goals. Examples would include, the design of a chemical stimulation to maximize the amplitude of a given cellular signal or to achieve a desired pattern in pattern formation systems, etc. Such design problems can be mathematically formulated as <span class="hlt">dynamic</span> <span class="hlt">optimization</span> problems which are particularly challenging when the system is described by partial differential equations. This work addresses the numerical solution of such <span class="hlt">dynamic</span> <span class="hlt">optimization</span> problems for spatially distributed biological systems. The usual nonlinear and large scale nature of the mathematical models related to this class of systems and the presence of constraints on the <span class="hlt">optimization</span> problems, impose a number of difficulties, such as the presence of suboptimal solutions, which call for robust and efficient numerical techniques. Results Here, the use of a control vector parameterization approach combined with efficient and robust hybrid global <span class="hlt">optimization</span> methods and a reduced order model methodology is proposed. The capabilities of this strategy are illustrated considering the solution of a two challenging problems: bacterial chemotaxis and the FitzHugh-Nagumo model. Conclusions In the process of chemotaxis the objective was to efficiently compute the time-varying <span class="hlt">optimal</span> concentration of chemotractant in one of the spatial boundaries in order to achieve predefined cell distribution profiles. Results are in agreement with those previously published in the literature. The FitzHugh-Nagumo problem is also efficiently solved and it illustrates very well how <span class="hlt">dynamic</span> <span class="hlt">optimization</span> may be used to force a system to evolve from an undesired to a desired pattern with a reduced number of actuators. The presented methodology can be used for the efficient <span class="hlt">dynamic</span> <span class="hlt">optimization</span> of generic distributed biological systems. PMID:22748139</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21059054','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21059054"><span id="translatedtitle"><span class="hlt">Optimal</span> purchasing of raw materials: A data-driven approach</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Muteki, K.; MacGregor, J.F.</p> <p>2008-06-15</p> <p>An approach to the <span class="hlt">optimal</span> purchasing of raw materials that will achieve a desired product quality at a minimum cost is presented. A PLS (Partial Least Squares) approach to formulation modeling is used to combine databases on raw material properties and on past process operations and to relate these to final product quality. These PLS latent variable models are then used in a sequential quadratic programming (SQP) or <span class="hlt">mixed</span> <span class="hlt">integer</span> nonlinear programming (MINLP) <span class="hlt">optimization</span> to select those raw-materials, among all those available on the market, the ratios in which to combine them and the process conditions under which they should be processed. The approach is illustrated for the <span class="hlt">optimal</span> purchasing of metallurgical coals for coke making in the steel industry.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4517487','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4517487"><span id="translatedtitle">Targeted Learning of the Mean Outcome under an <span class="hlt">Optimal</span> <span class="hlt">Dynamic</span> Treatment Rule</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>van der Laan, Mark J.; Luedtke, Alexander R.</p> <p>2015-01-01</p> <p>We consider estimation of and inference for the mean outcome under the <span class="hlt">optimal</span> <span class="hlt">dynamic</span> two time-point treatment rule defined as the rule that maximizes the mean outcome under the <span class="hlt">dynamic</span> treatment, where the candidate rules are restricted to depend only on a user-supplied subset of the baseline and intermediate covariates. This estimation problem is addressed in a statistical model for the data distribution that is nonparametric beyond possible knowledge about the treatment and censoring mechanism. This contrasts from the current literature that relies on parametric assumptions. We establish that the mean of the counterfactual outcome under the <span class="hlt">optimal</span> <span class="hlt">dynamic</span> treatment is a pathwise differentiable parameter under conditions, and develop a targeted minimum loss-based estimator (TMLE) of this target parameter. We establish asymptotic linearity and statistical inference for this estimator under specified conditions. In a sequentially randomized trial the statistical inference relies upon a second-order difference between the estimator of the <span class="hlt">optimal</span> <span class="hlt">dynamic</span> treatment and the <span class="hlt">optimal</span> <span class="hlt">dynamic</span> treatment to be asymptotically negligible, which may be a problematic condition when the rule is based on multivariate time-dependent covariates. To avoid this condition, we also develop TMLEs and statistical inference for data adaptive target parameters that are defined in terms of the mean outcome under the estimate of the <span class="hlt">optimal</span> <span class="hlt">dynamic</span> treatment. In particular, we develop a novel cross-validated TMLE approach that provides asymptotic inference under minimal conditions, avoiding the need for any empirical process conditions. We offer simulation results to support our theoretical findings. PMID:26236571</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930050979&hterms=zeros+poles&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dzeros%2Bpoles','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930050979&hterms=zeros+poles&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dzeros%2Bpoles"><span id="translatedtitle">Construction and parameterization of all static and <span class="hlt">dynamic</span> H2-<span class="hlt">optimal</span> state feedback solutions, <span class="hlt">optimal</span> fixed modes, and fixed decoupling zeros</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chen, Ben M.; Saberi, Ali; Sannuti, Peddapullaiah; Shamash, Yacov</p> <p>1993-01-01</p> <p>This paper considers an H2 <span class="hlt">optimization</span> problem via state feedback. The class of problems dealt with here are general singular type which have a left invertible transfer matrix function from the control input to the controlled output. This class subsumes the regular H2 <span class="hlt">optimization</span> problems. The paper constructs and parameterizes all the static and <span class="hlt">dynamic</span> H2 <span class="hlt">optimal</span> state feedback solutions. Moreover, all the eigenvalues of an <span class="hlt">optimal</span> closed-loop system are characterized. All <span class="hlt">optimal</span> closed-loop systems share a set of eigenvalues which are termed here as the <span class="hlt">optimal</span> fixed modes. Every H2 <span class="hlt">optimal</span> controller must assign among the closed-loop eigenvalues the set of <span class="hlt">optimal</span> fixed modes. This set of <span class="hlt">optimal</span> fixed modes includes a set of <span class="hlt">optimal</span> fixed decoupling zeros which shows the minimum absolutely necessary number and locations of pole-zero cancellations present in any H2 <span class="hlt">optimal</span> design. It is shown that both the sets of <span class="hlt">optimal</span> fixed modes and <span class="hlt">optimal</span> fixed decoupling zeros do not vary depending upon whether the static or the <span class="hlt">dynamic</span> controllers are used.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25794375','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25794375"><span id="translatedtitle">Adaptive <span class="hlt">optimal</span> control of highly dissipative nonlinear spatially distributed processes with neuro-<span class="hlt">dynamic</span> programming.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Luo, Biao; Wu, Huai-Ning; Li, Han-Xiong</p> <p>2015-04-01</p> <p>Highly dissipative nonlinear partial differential equations (PDEs) are widely employed to describe the system <span class="hlt">dynamics</span> of industrial spatially distributed processes (SDPs). In this paper, we consider the <span class="hlt">optimal</span> control problem of the general highly dissipative SDPs, and propose an adaptive <span class="hlt">optimal</span> control approach based on neuro-<span class="hlt">dynamic</span> programming (NDP). Initially, Karhunen-Loève decomposition is employed to compute empirical eigenfunctions (EEFs) of the SDP based on the method of snapshots. These EEFs together with singular perturbation technique are then used to obtain a finite-dimensional slow subsystem of ordinary differential equations that accurately describes the dominant <span class="hlt">dynamics</span> of the PDE system. Subsequently, the <span class="hlt">optimal</span> control problem is reformulated on the basis of the slow subsystem, which is further converted to solve a Hamilton-Jacobi-Bellman (HJB) equation. HJB equation is a nonlinear PDE that has proven to be impossible to solve analytically. Thus, an adaptive <span class="hlt">optimal</span> control method is developed via NDP that solves the HJB equation online using neural network (NN) for approximating the value function; and an online NN weight tuning law is proposed without requiring an initial stabilizing control policy. Moreover, by involving the NN estimation error, we prove that the original closed-loop PDE system with the adaptive <span class="hlt">optimal</span> control policy is semiglobally uniformly ultimately bounded. Finally, the developed method is tested on a nonlinear diffusion-convection-reaction process and applied to a temperature cooling fin of high-speed aerospace vehicle, and the achieved results show its effectiveness. PMID:25794375</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4101942','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4101942"><span id="translatedtitle">Improving the <span class="hlt">Dynamic</span> Characteristics of Body-in-White Structure Using Structural <span class="hlt">Optimization</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Yahaya Rashid, Aizzat S.; Mohamed Haris, Sallehuddin; Alias, Anuar</p> <p>2014-01-01</p> <p>The <span class="hlt">dynamic</span> behavior of a body-in-white (BIW) structure has significant influence on the noise, vibration, and harshness (NVH) and crashworthiness of a car. Therefore, by improving the <span class="hlt">dynamic</span> characteristics of BIW, problems and failures associated with resonance and fatigue can be prevented. The design objectives attempt to improve the existing torsion and bending modes by using structural <span class="hlt">optimization</span> subjected to <span class="hlt">dynamic</span> load without compromising other factors such as mass and stiffness of the structure. The natural frequency of the design was modified by identifying and reinforcing the structure at critical locations. These crucial points are first identified by topology <span class="hlt">optimization</span> using mass and natural frequencies as the design variables. The individual components obtained from the analysis go through a size <span class="hlt">optimization</span> step to find their target thickness of the structure. The thickness of affected regions of the components will be modified according to the analysis. The results of both <span class="hlt">optimization</span> steps suggest several design modifications to achieve the target vibration specifications without compromising the stiffness of the structure. A method of combining both <span class="hlt">optimization</span> approaches is proposed to improve the design modification process. PMID:25101312</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25101312','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25101312"><span id="translatedtitle">Improving the <span class="hlt">dynamic</span> characteristics of body-in-white structure using structural <span class="hlt">optimization</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yahaya Rashid, Aizzat S; Ramli, Rahizar; Mohamed Haris, Sallehuddin; Alias, Anuar</p> <p>2014-01-01</p> <p>The <span class="hlt">dynamic</span> behavior of a body-in-white (BIW) structure has significant influence on the noise, vibration, and harshness (NVH) and crashworthiness of a car. Therefore, by improving the <span class="hlt">dynamic</span> characteristics of BIW, problems and failures associated with resonance and fatigue can be prevented. The design objectives attempt to improve the existing torsion and bending modes by using structural <span class="hlt">optimization</span> subjected to <span class="hlt">dynamic</span> load without compromising other factors such as mass and stiffness of the structure. The natural frequency of the design was modified by identifying and reinforcing the structure at critical locations. These crucial points are first identified by topology <span class="hlt">optimization</span> using mass and natural frequencies as the design variables. The individual components obtained from the analysis go through a size <span class="hlt">optimization</span> step to find their target thickness of the structure. The thickness of affected regions of the components will be modified according to the analysis. The results of both <span class="hlt">optimization</span> steps suggest several design modifications to achieve the target vibration specifications without compromising the stiffness of the structure. A method of combining both <span class="hlt">optimization</span> approaches is proposed to improve the design modification process. PMID:25101312</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010IEITI..93..531Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010IEITI..93..531Z"><span id="translatedtitle">An <span class="hlt">Optimal</span> Algorithm towards Successive Location Privacy in Sensor Networks with <span class="hlt">Dynamic</span> Programming</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhao, Baokang; Wang, Dan; Shao, Zili; Cao, Jiannong; Chan, Keith C. C.; Su, Jinshu</p> <p></p> <p>In wireless sensor networks, preserving location privacy under successive inference attacks is extremely critical. Although this problem is NP-complete in general cases, we propose a <span class="hlt">dynamic</span> programming based algorithm and prove it is <span class="hlt">optimal</span> in special cases where the correlation only exists between p immediate adjacent observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=320519','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=320519"><span id="translatedtitle">Evaluation of <span class="hlt">dynamically</span> dimensioned search algorithm for <span class="hlt">optimizing</span> SWAT by altering sampling distributions and searching range</span></a></p> <p><a target="_blank" href="http://www.ars.usda.gov/services/TekTran.htm">Technology Transfer Automated Retrieval System (TEKTRAN)</a></p> <p></p> <p></p> <p>The primary advantage of <span class="hlt">Dynamically</span> Dimensioned Search algorithm (DDS) is that it outperforms many other <span class="hlt">optimization</span> techniques in both convergence speed and the ability in searching for parameter sets that satisfy statistical guidelines while requiring only one algorithm parameter (perturbation f...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24316385','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24316385"><span id="translatedtitle">COStar: a D-star Lite-based <span class="hlt">dynamic</span> search algorithm for codon <span class="hlt">optimization</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liu, Xiaowu; Deng, Riqiang; Wang, Jinwen; Wang, Xunzhang</p> <p>2014-03-01</p> <p>Codon <span class="hlt">optimized</span> genes have two major advantages: they simplify de novo gene synthesis and increase the expression level in target hosts. Often they achieve this by altering codon usage in a given gene. Codon <span class="hlt">optimization</span> is complex because it usually needs to achieve multiple opposing goals. In practice, finding an <span class="hlt">optimal</span> sequence from the massive number of possible combinations of synonymous codons that can code for the same amino acid sequence is a challenging task. In this article, we introduce COStar, a D-star Lite-based <span class="hlt">dynamic</span> search algorithm for codon <span class="hlt">optimization</span>. The algorithm first maps the codon <span class="hlt">optimization</span> problem into a weighted directed acyclic graph using a sliding window approach. Then, the D-star Lite algorithm is used to compute the shortest path from the start site to the target site in the resulting graph. <span class="hlt">Optimizing</span> a gene is thus converted to a search in real-time for a shortest path in a generated graph. Using in silico experiments, the performance of the algorithm was shown by <span class="hlt">optimizing</span> the different genes including the human genome. The results suggest that COStar is a promising codon <span class="hlt">optimization</span> tool for de novo gene synthesis and heterologous gene expression. PMID:24316385</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PhRvA..87d2319W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PhRvA..87d2319W"><span id="translatedtitle">No-go theorems and <span class="hlt">optimization</span> of <span class="hlt">dynamical</span> decoupling against noise with soft cutoff</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Zhen-Yu; Liu, Ren-Bao</p> <p>2013-04-01</p> <p>We study the performance of <span class="hlt">dynamical</span> decoupling in suppressing decoherence caused by soft-cutoff Gaussian noise, using short-time expansion of the noise correlations and numerical <span class="hlt">optimization</span>. For the noise with soft cutoff at high frequencies, there exists no <span class="hlt">dynamical</span> decoupling scheme to eliminate the decoherence to arbitrary orders of the short time, regardless of the timing or pulse shaping of the control under the population conserving condition. We formulate the equations for <span class="hlt">optimizing</span> pulse sequences that minimize decoherence up to the highest possible order of the short time for the noise correlations with odd power terms in the short-time expansion. In particular, we show that the Carr-Purcell-Meiboom-Gill sequence is <span class="hlt">optimal</span> in the short-time limit for the noise correlations with a linear order term in the time expansion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25420238','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25420238"><span id="translatedtitle"><span class="hlt">Optimal</span> control for unknown discrete-time nonlinear Markov jump systems using adaptive <span class="hlt">dynamic</span> programming.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhong, Xiangnan; He, Haibo; Zhang, Huaguang; Wang, Zhanshan</p> <p>2014-12-01</p> <p>In this paper, we develop and analyze an <span class="hlt">optimal</span> control method for a class of discrete-time nonlinear Markov jump systems (MJSs) with unknown system <span class="hlt">dynamics</span>. Specifically, an identifier is established for the unknown systems to approximate system states, and an <span class="hlt">optimal</span> control approach for nonlinear MJSs is developed to solve the Hamilton-Jacobi-Bellman equation based on the adaptive <span class="hlt">dynamic</span> programming technique. We also develop detailed stability analysis of the control approach, including the convergence of the performance index function for nonlinear MJSs and the existence of the corresponding admissible control. Neural network techniques are used to approximate the proposed performance index function and the control law. To demonstrate the effectiveness of our approach, three simulation studies, one linear case, one nonlinear case, and one single link robot arm case, are used to validate the performance of the proposed <span class="hlt">optimal</span> control method. PMID:25420238</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730019051','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730019051"><span id="translatedtitle">Perform - A performance <span class="hlt">optimizing</span> computer program for <span class="hlt">dynamic</span> systems subject to transient loadings</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pilkey, W. D.; Wang, B. P.; Yoo, Y.; Clark, B.</p> <p>1973-01-01</p> <p>A description and applications of a computer capability for determining the ultimate <span class="hlt">optimal</span> behavior of a <span class="hlt">dynamically</span> loaded structural-mechanical system are presented. This capability provides characteristics of the theoretically best, or limiting, design concept according to response criteria dictated by design requirements. Equations of motion of the system in first or second order form include incompletely specified elements whose characteristics are determined in the <span class="hlt">optimization</span> of one or more performance indices subject to the response criteria in the form of constraints. The system is subject to deterministic transient inputs, and the computer capability is designed to operate with a large linear programming on-the-shelf software package which performs the desired <span class="hlt">optimization</span>. The report contains user-oriented program documentation in engineering, problem-oriented form. Applications cover a wide variety of <span class="hlt">dynamics</span> problems including those associated with such diverse configurations as a missile-silo system, impacting freight cars, and an aircraft ride control system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016IJEEP..17..117S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016IJEEP..17..117S"><span id="translatedtitle">Coordinated Action of Fast and Slow Reserves for <span class="hlt">Optimal</span> Sequential and <span class="hlt">Dynamic</span> Emergency Reserve Activation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Salkuti, Surender Reddy; Bijwe, P. R.; Abhyankar, A. R.</p> <p>2016-04-01</p> <p>This paper proposes an <span class="hlt">optimal</span> <span class="hlt">dynamic</span> reserve activation plan after the occurrence of an emergency situation (generator/transmission line outage, load increase or both). An <span class="hlt">optimal</span> plan is developed to handle the emergency situation, using coordinated action of fast and slow reserves, for secure operation with minimum overall cost. This paper considers the reserves supplied by generators (spinning reserves) and loads (demand-side reserves). The <span class="hlt">optimal</span> backing down of costly/fast reserves and bringing up of slow reserves in each sub-interval in an integrated manner is proposed. The simulation studies are performed on IEEE 30, 57 and 300 bus test systems to demonstrate the advantage of proposed integrated/<span class="hlt">dynamic</span> reserve activation plan over the conventional/sequential approach.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26095711','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26095711"><span id="translatedtitle"><span class="hlt">Optimization</span> of multi-stage <span class="hlt">dynamic</span> treatment regimes utilizing accumulated data.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Huang, Xuelin; Choi, Sangbum; Wang, Lu; Thall, Peter F</p> <p>2015-11-20</p> <p>In medical therapies involving multiple stages, a physician's choice of a subject's treatment at each stage depends on the subject's history of previous treatments and outcomes. The sequence of decisions is known as a <span class="hlt">dynamic</span> treatment regime or treatment policy. We consider <span class="hlt">dynamic</span> treatment regimes in settings where each subject's final outcome can be defined as the sum of longitudinally observed values, each corresponding to a stage of the regime. Q-learning, which is a backward induction method, is used to first <span class="hlt">optimize</span> the last stage treatment then sequentially <span class="hlt">optimize</span> each previous stage treatment until the first stage treatment is <span class="hlt">optimized</span>. During this process, model-based expectations of outcomes of late stages are used in the <span class="hlt">optimization</span> of earlier stages. When the outcome models are misspecified, bias can accumulate from stage to stage and become severe, especially when the number of treatment stages is large. We demonstrate that a modification of standard Q-learning can help reduce the accumulated bias. We provide a computational algorithm, estimators, and closed-form variance formulas. Simulation studies show that the modified Q-learning method has a higher probability of identifying the <span class="hlt">optimal</span> treatment regime even in settings with misspecified models for outcomes. It is applied to identify <span class="hlt">optimal</span> treatment regimes in a study for advanced prostate cancer and to estimate and compare the final mean rewards of all the possible discrete two-stage treatment sequences. PMID:26095711</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19940004693&hterms=dynamic+programming&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Ddynamic%2Bprogramming','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19940004693&hterms=dynamic+programming&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Ddynamic%2Bprogramming"><span id="translatedtitle"><span class="hlt">Optimization</span> of rotor blades for combined structural, <span class="hlt">dynamic</span>, and aerodynamic properties</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>He, Cheng-Jian; Peters, David A.</p> <p>1990-01-01</p> <p><span class="hlt">Optimal</span> helicopter blade design with computer-based mathematical programming has received more and more attention in recent years. Most of the research has focused on optimum <span class="hlt">dynamic</span> characteristics of rotor blades to reduce vehicle vibration. There is also work on <span class="hlt">optimization</span> of aerodynamic performance and on composite structural design. This research has greatly increased our understanding of helicopter optimum design in each of these aspects. Helicopter design is an inherently multidisciplinary process involving strong interactions among various disciplines which can appropriately include aerodynamics; <span class="hlt">dynamics</span>, both flight <span class="hlt">dynamics</span> and structural <span class="hlt">dynamics</span>; aeroelasticity: vibrations and stability; and even acoustics. Therefore, the helicopter design process must satisfy manifold requirements related to the aforementioned diverse disciplines. In our present work, we attempt to combine several of these important effects in a unified manner. First, we design a blade with optimum aerodynamic performance by proper layout of blade planform and spanwise twist. Second, the blade is designed to have natural frequencies that are placed away from integer multiples of the rotor speed for a good <span class="hlt">dynamic</span> characteristics. Third, the structure is made as light as possible with sufficient rotational inertia to allow for autorotational landing, with safe stress margins and flight fatigue life at each cross-section, and with aeroelastical stability and low vibrations. Finally, a unified <span class="hlt">optimization</span> refines the solution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20040087025','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20040087025"><span id="translatedtitle">Multidisciplinary Design <span class="hlt">Optimization</span> Techniques: Implications and Opportunities for Fluid <span class="hlt">Dynamics</span> Research</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Zang, Thomas A.; Green, Lawrence L.</p> <p>1999-01-01</p> <p>A challenge for the fluid <span class="hlt">dynamics</span> community is to adapt to and exploit the trend towards greater multidisciplinary focus in research and technology. The past decade has witnessed substantial growth in the research field of Multidisciplinary Design <span class="hlt">Optimization</span> (MDO). MDO is a methodology for the design of complex engineering systems and subsystems that coherently exploits the synergism of mutually interacting phenomena. As evidenced by the papers, which appear in the biannual AIAA/USAF/NASA/ISSMO Symposia on Multidisciplinary Analysis and <span class="hlt">Optimization</span>, the MDO technical community focuses on vehicle and system design issues. This paper provides an overview of the MDO technology field from a fluid <span class="hlt">dynamics</span> perspective, giving emphasis to suggestions of specific applications of recent MDO technologies that can enhance fluid <span class="hlt">dynamics</span> research itself across the spectrum, from basic flow physics to full configuration aerodynamics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4574939','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4574939"><span id="translatedtitle">Efficient <span class="hlt">Optimization</span> of Stimuli for Model-Based Design of Experiments to Resolve <span class="hlt">Dynamical</span> Uncertainty</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Mdluli, Thembi; Buzzard, Gregery T.; Rundell, Ann E.</p> <p>2015-01-01</p> <p>This model-based design of experiments (MBDOE) method determines the input magnitudes of an experimental stimuli to apply and the associated measurements that should be taken to <span class="hlt">optimally</span> constrain the uncertain <span class="hlt">dynamics</span> of a biological system under study. The ideal global solution for this experiment design problem is generally computationally intractable because of parametric uncertainties in the mathematical model of the biological system. Others have addressed this issue by limiting the solution to a local estimate of the model parameters. Here we present an approach that is independent of the local parameter constraint. This approach is made computationally efficient and tractable by the use of: (1) sparse grid interpolation that approximates the biological system <span class="hlt">dynamics</span>, (2) representative parameters that uniformly represent the data-consistent <span class="hlt">dynamical</span> space, and (3) probability weights of the represented experimentally distinguishable <span class="hlt">dynamics</span>. Our approach identifies data-consistent representative parameters using sparse grid interpolants, constructs the <span class="hlt">optimal</span> input sequence from a greedy search, and defines the associated <span class="hlt">optimal</span> measurements using a scenario tree. We explore the <span class="hlt">optimality</span> of this MBDOE algorithm using a 3-dimensional Hes1 model and a 19-dimensional T-cell receptor model. The 19-dimensional T-cell model also demonstrates the MBDOE algorithm’s scalability to higher dimensions. In both cases, the <span class="hlt">dynamical</span> uncertainty region that bounds the trajectories of the target system states were reduced by as much as 86% and 99% respectively after completing the designed experiments in silico. Our results suggest that for resolving <span class="hlt">dynamical</span> uncertainty, the ability to design an input sequence paired with its associated measurements is particularly important when limited by the number of measurements. PMID:26379275</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20060039111&hterms=history+trains&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dhistory%2Btrains','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20060039111&hterms=history+trains&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dhistory%2Btrains"><span id="translatedtitle">Synthesis of <span class="hlt">Optimal</span> Nonlinear Feedback Laws for <span class="hlt">Dynamic</span> Systems Using Neural Networks</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lee, Allan Y.; Smyth, Padhraic</p> <p>1993-01-01</p> <p>Open-loop solutions of <span class="hlt">dynamical</span> <span class="hlt">optimization</span> problems can be numerically computed usingexisting software packages. The computed time histories of the state and control variables, formultiple sets of end conditions can then be used to train a neural network to 'recognize' the <span class="hlt">optimal</span>,nonlinear feedback relation between the states and controls of the system. The 'learned' network canthen be used to output an approximate <span class="hlt">optimal</span> control given a full set (or a partial set) of measuredsystem states. With simple neural networks, we have successfully demonstrated the efficacy of theproposed approach using a minimum-time orbit injection problem. The usefulness and limitations ofthis novel approach on real-life <span class="hlt">optimal</span> guidance and control problems, with many state and control variables as well as path inequality constraints, remain to be seen.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ChPhB..24c0502W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ChPhB..24c0502W"><span id="translatedtitle">Policy iteration <span class="hlt">optimal</span> tracking control for chaotic systems by using an adaptive <span class="hlt">dynamic</span> programming approach</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wei, Qing-Lai; Liu, De-Rong; Xu, Yan-Cai</p> <p>2015-03-01</p> <p>A policy iteration algorithm of adaptive <span class="hlt">dynamic</span> programming (ADP) is developed to solve the <span class="hlt">optimal</span> tracking control for a class of discrete-time chaotic systems. By system transformations, the <span class="hlt">optimal</span> tracking problem is transformed into an <span class="hlt">optimal</span> regulation one. The policy iteration algorithm for discrete-time chaotic systems is first described. Then, the convergence and admissibility properties of the developed policy iteration algorithm are presented, which show that the transformed chaotic system can be stabilized under an arbitrary iterative control law and the iterative performance index function simultaneously converges to the optimum. By implementing the policy iteration algorithm via neural networks, the developed <span class="hlt">optimal</span> tracking control scheme for chaotic systems is verified by a simulation. Project supported by the National Natural Science Foundation of China (Grant Nos. 61034002, 61233001, 61273140, 61304086, and 61374105) and the Beijing Natural Science Foundation, China (Grant No. 4132078).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20080250','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20080250"><span id="translatedtitle">Multiple criteria <span class="hlt">dynamic</span> spatial <span class="hlt">optimization</span> to manage water quality on a watershed scale</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Randhir, T.O.; Lee, J.G.; Engel, B.</p> <p>2000-04-01</p> <p>This article develops a <span class="hlt">dynamic</span> spatial <span class="hlt">optimization</span> algorithm for watershed modeling that reduces dimensionality and incorporates multiple objectives. Spatial <span class="hlt">optimization</span> methods, which include spatially linear and nonlinear formulations, are applied to an experimental watershed and tested against a full enumeration frontier. The integrated algorithm includes biophysical simulation and economic decision-making within a geographic information system. It was observed that it is possible to achieve economic and water quality objectives in a watershed by spatially <span class="hlt">optimizing</span> site-specific practices. It was observed that a spatially diversified watershed plan could achieve multiple goals in a watershed. The algorithm can be used to develop efficient policies towards environmental management of watersheds to address water quality issues by identifying <span class="hlt">optimal</span> tradeoffs across objectives.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009WRR....4512416T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009WRR....4512416T"><span id="translatedtitle">Hybrid discrete <span class="hlt">dynamically</span> dimensioned search (HD-DDS) algorithm for water distribution system design <span class="hlt">optimization</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tolson, Bryan A.; Asadzadeh, Masoud; Maier, Holger R.; Zecchin, Aaron</p> <p>2009-12-01</p> <p>The <span class="hlt">dynamically</span> dimensioned search (DDS) continuous global <span class="hlt">optimization</span> algorithm by Tolson and Shoemaker (2007) is modified to solve discrete, single-objective, constrained water distribution system (WDS) design problems. The new global <span class="hlt">optimization</span> algorithm for WDS <span class="hlt">optimization</span> is called hybrid discrete <span class="hlt">dynamically</span> dimensioned search (HD-DDS) and combines two local search heuristics with a discrete DDS search strategy adapted from the continuous DDS algorithm. The main advantage of the HD-DDS algorithm compared with other heuristic global <span class="hlt">optimization</span> algorithms, such as genetic and ant colony algorithms, is that its searching capability (i.e., the ability to find near globally <span class="hlt">optimal</span> solutions) is as good, if not better, while being significantly more computationally efficient. The algorithm's computational efficiency is due to a number of factors, including the fact that it is not a population-based algorithm and only requires computationally expensive hydraulic simulations to be conducted for a fraction of the solutions evaluated. This paper introduces and evaluates the algorithm by comparing its performance with that of three other algorithms (specific versions of the genetic algorithm, ant colony <span class="hlt">optimization</span>, and particle swarm <span class="hlt">optimization</span>) on four WDS case studies (21- to 454-dimensional <span class="hlt">optimization</span> problems) on which these algorithms have been found to perform well. The results obtained indicate that the HD-DDS algorithm outperforms the state-of-the-art existing algorithms in terms of searching ability and computational efficiency. In addition, the algorithm is easier to use, as it does not require any parameter tuning and automatically adjusts its search to find good solutions given the available computational budget.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014APS..GECMW1077K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014APS..GECMW1077K"><span id="translatedtitle"><span class="hlt">Optimizing</span> Natural Gas Networks through <span class="hlt">Dynamic</span> Manifold Theory and a Decentralized Algorithm: Belgium Case Study</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Koch, Caleb; Winfrey, Leigh</p> <p>2014-10-01</p> <p>Natural Gas is a major energy source in Europe, yet political instabilities have the potential to disrupt access and supply. Energy resilience is an increasingly essential construct and begins with transmission network design. This study proposes a new way of thinking about modelling natural gas flow. Rather than relying on classical economic models, this problem is cast into a time-dependent Hamiltonian <span class="hlt">dynamics</span> discussion. Traditional Natural Gas constraints, including inelastic demand and maximum/minimum pipe flows, are portrayed as energy functions and built into the <span class="hlt">dynamics</span> of each pipe flow. Doing so allows the constraints to be built into the <span class="hlt">dynamics</span> of each pipeline. As time progresses in the model, natural gas flow rates find the minimum energy, thus the <span class="hlt">optimal</span> gas flow rates. The most important result of this study is using <span class="hlt">dynamical</span> principles to ensure the output of natural gas at demand nodes remains constant, which is important for country to country natural gas transmission. Another important step in this study is building the <span class="hlt">dynamics</span> of each flow in a decentralized algorithm format. Decentralized regulation has solved congestion problems for internet data flow, traffic flow, epidemiology, and as demonstrated in this study can solve the problem of Natural Gas congestion. A mathematical description is provided for how decentralized regulation leads to globally <span class="hlt">optimized</span> network flow. Furthermore, the <span class="hlt">dynamical</span> principles and decentralized algorithm are applied to a case study of the Fluxys Belgium Natural Gas Network.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JMSA...11..286M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JMSA...11..286M"><span id="translatedtitle">Computational fluid <span class="hlt">dynamics</span> based bulbous bow <span class="hlt">optimization</span> using a genetic algorithm</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mahmood, Shahid; Huang, Debo</p> <p>2012-09-01</p> <p>Computational fluid <span class="hlt">dynamics</span> (CFD) plays a major role in predicting the flow behavior of a ship. With the development of fast computers and robust CFD software, CFD has become an important tool for designers and engineers in the ship industry. In this paper, the hull form of a ship was <span class="hlt">optimized</span> for total resistance using CFD as a calculation tool and a genetic algorithm as an <span class="hlt">optimization</span> tool. CFD based <span class="hlt">optimization</span> consists of major steps involving automatic generation of geometry based on design parameters, automatic generation of mesh, automatic analysis of fluid flow to calculate the required objective/cost function, and finally an <span class="hlt">optimization</span> tool to evaluate the cost for <span class="hlt">optimization</span>. In this paper, integration of a genetic algorithm program, written in MATLAB, was carried out with the geometry and meshing software GAMBIT and CFD analysis software FLUENT. Different geometries of additive bulbous bow were incorporated in the original hull based on design parameters. These design variables were <span class="hlt">optimized</span> to achieve a minimum cost function of "total resistance". Integration of a genetic algorithm with CFD tools proves to be effective for hull form <span class="hlt">optimization</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20130014121','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20130014121"><span id="translatedtitle">Risk-Constrained <span class="hlt">Dynamic</span> Programming for <span class="hlt">Optimal</span> Mars Entry, Descent, and Landing</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ono, Masahiro; Kuwata, Yoshiaki</p> <p>2013-01-01</p> <p>A chance-constrained <span class="hlt">dynamic</span> programming algorithm was developed that is capable of making <span class="hlt">optimal</span> sequential decisions within a user-specified risk bound. This work handles stochastic uncertainties over multiple stages in the CEMAT (Combined EDL-Mobility Analyses Tool) framework. It was demonstrated by a simulation of Mars entry, descent, and landing (EDL) using real landscape data obtained from the Mars Reconnaissance Orbiter. Although standard <span class="hlt">dynamic</span> programming (DP) provides a general framework for <span class="hlt">optimal</span> sequential decisionmaking under uncertainty, it typically achieves risk aversion by imposing an arbitrary penalty on failure states. Such a penalty-based approach cannot explicitly bound the probability of mission failure. A key idea behind the new approach is called risk allocation, which decomposes a joint chance constraint into a set of individual chance constraints and distributes risk over them. The joint chance constraint was reformulated into a constraint on an expectation over a sum of an indicator function, which can be incorporated into the cost function by dualizing the <span class="hlt">optimization</span> problem. As a result, the chance-constraint <span class="hlt">optimization</span> problem can be turned into an unconstrained <span class="hlt">optimization</span> over a Lagrangian, which can be solved efficiently using a standard DP approach.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016APS..MAR.T1321H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016APS..MAR.T1321H"><span id="translatedtitle"><span class="hlt">Optimal</span> bipedal interactions with <span class="hlt">dynamic</span> terrain: synthesis and analysis via nonlinear programming</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hubicki, Christian; Goldman, Daniel; Ames, Aaron</p> <p></p> <p>In terrestrial locomotion, gait <span class="hlt">dynamics</span> and motor control behaviors are tuned to interact efficiently and stably with the <span class="hlt">dynamics</span> of the terrain (i.e. terradynamics). This controlled interaction must be particularly thoughtful in bipeds, as their reduced contact points render them highly susceptible to falls. While bipedalism under rigid terrain assumptions is well-studied, insights for two-legged locomotion on soft terrain, such as sand and dirt, are comparatively sparse. We seek an understanding of how biological bipeds stably and economically negotiate granular media, with an eye toward imbuing those abilities in bipedal robots. We present a trajectory <span class="hlt">optimization</span> method for controlled systems subject to granular intrusion. By formulating a large-scale nonlinear program (NLP) with reduced-order resistive force theory (RFT) models and jamming cone <span class="hlt">dynamics</span>, the <span class="hlt">optimized</span> motions are informed and shaped by the <span class="hlt">dynamics</span> of the terrain. Using a variant of direct collocation methods, we can express all <span class="hlt">optimization</span> objectives and constraints in closed-form, resulting in rapid solving by standard NLP solvers, such as IPOPT. We employ this tool to analyze emergent features of bipedal locomotion in granular media, with an eye toward robotic implementation.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..DFDH29006K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..DFDH29006K"><span id="translatedtitle"><span class="hlt">Dynamic</span> reconstruction of sub-sampled data using <span class="hlt">Optimal</span> Mode Decomposition</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Krol, Jakub; Wynn, Andrew</p> <p>2015-11-01</p> <p>The Nyquist-Shannon criterion indicates the sample rate necessary to identify information with particular frequency content from a <span class="hlt">dynamical</span> system. However, in experimental applications such as the interrogation of a flow field using Particle Image Velocimetry (PIV), it may be expensive to obtain data at the desired temporal resolution. To address this problem, we propose a new approach to identify temporal information from undersampled data, using ideas from modal decomposition algorithms such as <span class="hlt">Dynamic</span> Mode Decomposition (DMD) and <span class="hlt">Optimal</span> Mode Decomposition (OMD). The novel method takes a vector-valued signal sampled at random time instances (but at Sub-Nyquist rate) and projects onto a low-order subspace. Subsequently, <span class="hlt">dynamical</span> characteristics are approximated by iteratively approximating the flow evolution by a low order model and solving a certain convex <span class="hlt">optimization</span> problem. Furthermore, it is shown that constraints may be added to the <span class="hlt">optimization</span> problem to improve spatial resolution of missing data points. The methodology is demonstrated on two <span class="hlt">dynamical</span> systems, a cylinder flow at Re = 60 and Kuramoto-Sivashinsky equation. In both cases the algorithm correctly identifies the characteristic frequencies and oscillatory structures present in the flow.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22251304','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22251304"><span id="translatedtitle">Extended Lagrangian Born-Oppenheimer molecular <span class="hlt">dynamics</span> in the limit of vanishing self-consistent field <span class="hlt">optimization</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Souvatzis, Petros; Niklasson, Anders M. N.</p> <p>2013-12-07</p> <p>We present an efficient general approach to first principles molecular <span class="hlt">dynamics</span> simulations based on extended Lagrangian Born-Oppenheimer molecular <span class="hlt">dynamics</span> [A. M. N. Niklasson, Phys. Rev. Lett. 100, 123004 (2008)] in the limit of vanishing self-consistent field <span class="hlt">optimization</span>. The reduction of the <span class="hlt">optimization</span> requirement reduces the computational cost to a minimum, but without causing any significant loss of accuracy or long-term energy drift. The <span class="hlt">optimization</span>-free first principles molecular <span class="hlt">dynamics</span> requires only one single diagonalization per time step, but is still able to provide trajectories at the same level of accuracy as exact, fully converged, Born-Oppenheimer molecular <span class="hlt">dynamics</span> simulations. The <span class="hlt">optimization</span>-free limit of extended Lagrangian Born-Oppenheimer molecular <span class="hlt">dynamics</span> therefore represents an ideal starting point for robust and efficient first principles quantum mechanical molecular <span class="hlt">dynamics</span> simulations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AIPC.1499..187V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AIPC.1499..187V"><span id="translatedtitle"><span class="hlt">Optimized</span> stiffness for linear time-invariant <span class="hlt">dynamic</span> system according to a new system design</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Veeraklaew, Tawiwat</p> <p>2012-11-01</p> <p>This paper deals with a linear time-invariant <span class="hlt">dynamic</span> system such as spring-mass-damper system. General <span class="hlt">dynamic</span> systems are quite commonly to be redesigned for another purpose of using. For example, if one automobile must be redesigned to have more weights, the existing suspension must be replaced due to that gained weight. Therefore the stiffness and damping coefficient must be recomputed in order to make the automobile become suitable for using as previous. Here the spring-mass-damper system is used as an example to demonstrate the technique through <span class="hlt">dynamic</span> <span class="hlt">optimization</span> where the problem is solved in two categories as minimum energy and maximum jerk. Once the state and control variables are provided from the problem of minimum energy and maximum jerk, respectively, these parameter will be substituted in <span class="hlt">dynamic</span> equations and leave the stiffness and damping coefficient as the unknown parameters to be solved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3918502','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3918502"><span id="translatedtitle"><span class="hlt">Dynamic</span> Imaging of Genomic Loci in Living Human Cells by an <span class="hlt">Optimized</span> CRISPR/Cas System</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Chen, Baohui; Gilbert, Luke A.; Cimini, Beth A.; Schnitzbauer, Joerg; Zhang, Wei; Li, Gene-Wei; Park, Jason; Blackburn, Elizabeth H.; Weissman, Jonathan S.; Qi, Lei S.; Huang, Bo</p> <p>2014-01-01</p> <p>SUMMARY The spatiotemporal organization and <span class="hlt">dynamics</span> of chromatin play critical roles in regulating genome function. However, visualizing specific, endogenous genomic loci remains challenging in living cells. Here, we demonstrate such an imaging technique by repurposing the bacterial CRISPR/Cas system. Using an EGFP-tagged endonuclease-deficient Cas9 protein and a structurally <span class="hlt">optimized</span> small guide (sg) RNA, we show robust imaging of repetitive elements in telomeres and coding genes in living cells. Furthermore, an array of sgRNAs tiling along the target locus enables the visualization of non-repetitive genomic sequences. Using this method, we have studied telomere <span class="hlt">dynamics</span> during elongation or disruption, the subnuclear localization of the MUC4 loci, the cohesion of replicated MUC4 loci on sister chromatids, and their <span class="hlt">dynamic</span> behaviors during mitosis. This CRISPR imaging tool has potential to significantly improve the capacity to study the conformation and <span class="hlt">dynamics</span> of native chromosomes in living human cells. PMID:24360272</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/934620','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/934620"><span id="translatedtitle">Reduced-Order Model for <span class="hlt">Dynamic</span> <span class="hlt">Optimization</span> of Pressure Swing Adsorption</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Agarwal, Anshul; Biegler, L.T.; Zitney, S.E.</p> <p>2007-11-01</p> <p>The last few decades have seen a considerable increase in the applications of adsorptive gas separation technologies, such as pressure swing adsorption (PSA). From an economic and environmental point of view, hydrogen separation and carbon dioxide capture from flue gas streams are the most promising applications of PSA. With extensive industrial applications, there is a significant interest for an efficient modeling, simulation, and <span class="hlt">optimization</span> strategy. However, the design and <span class="hlt">optimization</span> of the PSA processes have largely remained an experimental effort because of the complex nature of the mathematical models describing practical PSA processes. The separation processes are based on solid-gas equilibrium and operate under periodic transient conditions. Models for PSA processes are therefore multiple instances of partial differential equations (PDEs) in time and space with periodic boundary conditions that link the processing steps together and high nonlinearities arising from non-isothermal effects. The computational effort required to solve such systems is usually quite expensive and prohibitively time consuming. Besides this, stringent product specifications, required by many industrial processes, often lead to convergence failures of the <span class="hlt">optimizers</span>. The solution of this coupled stiff PDE system is governed by steep concentrations and temperature fronts moving with time. As a result, the <span class="hlt">optimization</span> of such systems for either design or operation represents a significant computational challenge to current differential algebraic equation (DAE) <span class="hlt">optimization</span> techniques and nonlinear programming algorithms. Sophisticated <span class="hlt">optimization</span> strategies have been developed and applied to PSA systems with significant improvement in the performance of the process. However, most of these approaches have been quite time consuming. This gives a strong motivation to develop cost-efficient and robust <span class="hlt">optimization</span> strategies for PSA processes. Moreover, in case of flowsheet <span class="hlt">optimization</span>, if <span class="hlt">dynamic</span> PSA models are incorporated with other steady state models in the flowsheet then it will require much faster approaches for integrated <span class="hlt">optimization</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006PhDT.......101K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006PhDT.......101K"><span id="translatedtitle">Analysis and formulation of a class of complex <span class="hlt">dynamic</span> <span class="hlt">optimization</span> problems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kameswaran, Shivakumar</p> <p></p> <p>The Direct Transcription approach, also known as the direct simultaneous approach, is a widely used solution strategy for the solution of <span class="hlt">dynamic</span> <span class="hlt">optimization</span> problems involving differential-algebraic equations (DAEs). Direct transcription refers to the procedure of approximating the infinite dimensional problem by a finite dimensional one, which is then solved using a nonlinear programming (NLP) solver tailored to large-scale problems. Systems governed by partial differential equations (PDEs) can also be handled by spatially discretizing the PDEs to convert them to a system of DAEs. The objective of this thesis is firstly to ensure that direct transcription using Radau collocation is provably correct, and secondly to widen the applicability of the direct simultaneous approach to a larger class of <span class="hlt">dynamic</span> <span class="hlt">optimization</span> and <span class="hlt">optimal</span> control problems (OCPs). This thesis aims at addressing these issues using rigorous theoretical tools and/or characteristic examples, and at the same time use the results for solving large-scale industrial applications to realize the benefits. The first part of this work deals with the analysis of convergence rates for direct transcription of unconstrained and final-time equality constrained <span class="hlt">optimal</span> control problems. The problems are discretized using collocation at Radau points. Convergence is analyzed from an NLP/matrix-algebra perspective, which enables the prediction of the conditioning of the direct transcription NLP as the mesh size becomes finer. Several convergence results are presented along with tests on numerous example problems. These convergence results lead to an adjoint estimation procedure given the Lagrange multipliers for the large-scale NLP. The work also reveals the role of process control concepts such as controllability on the convergence analysis, and provides a very important link between control and <span class="hlt">optimization</span> inside the framework of <span class="hlt">dynamic</span> <span class="hlt">optimization</span>. As an effort to extend the applicability of the direct simultaneous approach to a wider class of problems, a PDE-constrained <span class="hlt">optimal</span> control problem, the spatial discretization of which results in a DAE-constrained problem with an arbitrarily high-index inequality constraint, is studied. <span class="hlt">Optimal</span> control problems with high-index path constraints are very hard to solve, numerically. Contrary to the intuitive belief that the direct transcription approach would not work for the high-index <span class="hlt">optimal</span> control problem, an analysis is performed to show that NLP-based methods have flexibility with respect to constraint qualifications, and this can be put to use in the context of high-index inequality path-constrained problems to obtain meaningful solutions. (Abstract shortened by UMI.)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/110041','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/110041"><span id="translatedtitle">Flow cells for bioanalytical and bioprocess applications with <span class="hlt">optimized</span> <span class="hlt">dynamic</span> response and flow characteristics</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lancaster, V.R.; Modlin, D.N.</p> <p>1994-12-31</p> <p>In this study, the authors present a method for design and characterization of flow cells developed for minimum flow volume and <span class="hlt">optimal</span> <span class="hlt">dynamic</span> response with a given central observation area. The <span class="hlt">dynamic</span> response of a circular shaped dual ported flow cell was compared to that obtained from a flow cell whose <span class="hlt">optimized</span> shape was determined using this method. In the <span class="hlt">optimized</span> flow cell design, the flow rate at the nominal operating pressure increased by 50% whereas the flow cell volume was reduced by 70%. In addition, the <span class="hlt">dynamic</span> response of the new flow cell was found to be 200% faster than the circular flow cell. The fluid <span class="hlt">dynamic</span> analysis included simple graphical techniques utilizing free stream vorticity functions and Hagen-Poiseuille relationships. The flow cell <span class="hlt">dynamic</span> response was measured using a fluorescence detection system. The fluoresce in emission from a 400{micro}m spot located at the exit port was measured as a function of time after switching the input to the flow cell between fluorescent and non-fluorescent solutions. Analysis of results revealed the system could be reasonably characterized as a first order <span class="hlt">dynamic</span> system. Although some evidence of second order behavior was also observed, it is reasonable to assume that a first order model will provide adequate predictive capability for many real world applications. Given a set of flow cell requirements, the methods presented in this study can be used to design and characterize flow cells with lower reagent consumption and reduced purging times. These improvements can be readily translated into reduced process times and/or lower usage of high cost reagents.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011LNCS.6589..260K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011LNCS.6589..260K"><span id="translatedtitle">An Approach for <span class="hlt">Dynamic</span> <span class="hlt">Optimization</span> of Prevention Program Implementation in Stochastic Environments</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kang, Yuncheol; Prabhu, Vittal</p> <p></p> <p>The science of preventing youth problems has significantly advanced in developing evidence-based prevention program (EBP) by using randomized clinical trials. Effective EBP can reduce delinquency, aggression, violence, bullying and substance abuse among youth. Unfortunately the outcomes of EBP implemented in natural settings usually tend to be lower than in clinical trials, which has motivated the need to study EBP implementations. In this paper we propose to model EBP implementations in natural settings as stochastic <span class="hlt">dynamic</span> processes. Specifically, we propose Markov Decision Process (MDP) for modeling and <span class="hlt">dynamic</span> <span class="hlt">optimization</span> of such EBP implementations. We illustrate these concepts using simple numerical examples and discuss potential challenges in using such approaches in practice.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19900020067','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19900020067"><span id="translatedtitle">An enhanced integrated aerodynamic load/<span class="hlt">dynamic</span> <span class="hlt">optimization</span> procedure for helicopter rotor blades</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chattopadhyay, Aditi; Chiu, Y. Danny</p> <p>1990-01-01</p> <p>An enhanced integrated aerodynamic load/<span class="hlt">dynamic</span> <span class="hlt">optimization</span> procedure is developed to minimize vibratory root shears and moments. The <span class="hlt">optimization</span> is formulated with 4/rev vertical and 3/rev inplane shears at the blade root as objective functions and constraints, and 4/rev lagging moment. Constraints are also imposed on blade natural frequencies, weight, autorotational inertia, centrifugal stress, and rotor thrust. The 'Global Criteria Approach' is used for formulating the multi-objective <span class="hlt">optimization</span>. Design variables include spanwise distributions of bending stiffnesses, torsional stiffness, nonstructural mass, chord, radius of gyration, and blade taper ratio. The program CAMRAD is coupled with an <span class="hlt">optimizer</span>, which consists of the program CONMIN and an approximate analysis, to obtain optimum designs. The <span class="hlt">optimization</span> procedure is applied to an advanced rotor as a reference design. Optimum blade designs, obtained with and without a constraint on the rotor thrust, are presented and are compared to the reference blade. Substantial reductions are obtained in the vibratory root forces and moments. As a byproduct, improvements are also found in some performance parameters, such as total power required, which were not considered during <span class="hlt">optimization</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/12583402','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/12583402"><span id="translatedtitle">Human motion planning based on recursive <span class="hlt">dynamics</span> and <span class="hlt">optimal</span> control techniques.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lo, Janzen; Huang, Gang; Metaxas, Dimitris</p> <p>2002-11-01</p> <p>This paper presents an efficient <span class="hlt">optimal</span> control and recursive <span class="hlt">dynamics</span>-based computer animation system for simulating and controlling the motion of articulated figures. A quasi-Newton nonlinear programming technique (super-linear convergence) is implemented to solve minimum torque-based human motion-planning problems. The explicit analytical gradients needed in the <span class="hlt">dynamics</span> are derived using a matrix exponential formulation and Lie algebra. Cubic spline functions are used to make the search space for an <span class="hlt">optimal</span> solution finite. Based on our formulations, our method is well conditioned and robust, in addition to being computationally efficient. To better illustrate the efficiency of our method, we present results of natural looking and physically correct human motions for a variety of human motion tasks involving open and closed loop kinematic chains. PMID:12583402</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002CompM..28..456Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002CompM..28..456Y"><span id="translatedtitle">Iterative mesh partitioning <span class="hlt">optimization</span> for parallel nonlinear <span class="hlt">dynamic</span> finite element analysis with direct substructuring</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Y.-S.; Hsieh, S.-H.</p> <p></p> <p>This work presents a novel iterative approach for mesh partitioning <span class="hlt">optimization</span> to promote the efficiency of parallel nonlinear <span class="hlt">dynamic</span> finite element analysis with the direct substructure method, which involves static condensation of substructures' internal degrees of freedom. The proposed approach includes four major phases - initial partitioning, substructure workload prediction, element weights tuning, and partitioning results adjustment. The final three phases are performed iteratively until the workloads among the substructures are balanced reasonably. A substructure workload predictor that considers the sparsity and ordering of the substructure matrix is used in the proposed approach. Several numerical experiments conducted herein reveal that the proposed iterative mesh partitioning <span class="hlt">optimization</span> often results in a superior workload balance among substructures and reduces the total elapsed time of the corresponding parallel nonlinear <span class="hlt">dynamic</span> finite element analysis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20040087841&hterms=anatomy+human&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Danatomy%2Bhuman','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20040087841&hterms=anatomy+human&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Danatomy%2Bhuman"><span id="translatedtitle">Human motion planning based on recursive <span class="hlt">dynamics</span> and <span class="hlt">optimal</span> control techniques</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lo, Janzen; Huang, Gang; Metaxas, Dimitris</p> <p>2002-01-01</p> <p>This paper presents an efficient <span class="hlt">optimal</span> control and recursive <span class="hlt">dynamics</span>-based computer animation system for simulating and controlling the motion of articulated figures. A quasi-Newton nonlinear programming technique (super-linear convergence) is implemented to solve minimum torque-based human motion-planning problems. The explicit analytical gradients needed in the <span class="hlt">dynamics</span> are derived using a matrix exponential formulation and Lie algebra. Cubic spline functions are used to make the search space for an <span class="hlt">optimal</span> solution finite. Based on our formulations, our method is well conditioned and robust, in addition to being computationally efficient. To better illustrate the efficiency of our method, we present results of natural looking and physically correct human motions for a variety of human motion tasks involving open and closed loop kinematic chains.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/18784011','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/18784011"><span id="translatedtitle">PSO-based multiobjective <span class="hlt">optimization</span> with <span class="hlt">dynamic</span> population size and adaptive local archives.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Leong, Wen-Fung; Yen, Gary G</p> <p>2008-10-01</p> <p>Recently, various multiobjective particle swarm <span class="hlt">optimization</span> (MOPSO) algorithms have been developed to efficiently and effectively solve multiobjective <span class="hlt">optimization</span> problems. However, the existing MOPSO designs generally adopt a notion to "estimate" a fixed population size sufficiently to explore the search space without incurring excessive computational complexity. To address the issue, this paper proposes the integration of a <span class="hlt">dynamic</span> population strategy within the multiple-swarm MOPSO. The proposed algorithm is named <span class="hlt">dynamic</span> population multiple-swarm MOPSO. An additional feature, adaptive local archives, is designed to improve the diversity within each swarm. Performance metrics and benchmark test functions are used to examine the performance of the proposed algorithm compared with that of five selected MOPSOs and two selected multiobjective evolutionary algorithms. In addition, the computational cost of the proposed algorithm is quantified and compared with that of the selected MOPSOs. The proposed algorithm shows competitive results with improved diversity and convergence and demands less computational cost. PMID:18784011</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27203482','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27203482"><span id="translatedtitle">A <span class="hlt">dynamic</span> oppositional biogeography-based <span class="hlt">optimization</span> approach for time-varying electrical impedance tomography.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rashid, A; Kim, S; Liu, D; Kim, K Y</p> <p>2016-06-01</p> <p><span class="hlt">Dynamic</span> electrical impedance tomography-based image reconstruction using conventional algorithms such as the extended Kalman filter often exhibits inferior performance due to the presence of measurement noise, the inherent ill-posed nature of the problem and its critical dependence on the selection of the initial guess as well as the state evolution model. Moreover, many of these conventional algorithms require the calculation of a Jacobian matrix. This paper proposes a <span class="hlt">dynamic</span> oppositional biogeography-based <span class="hlt">optimization</span> (OBBO) technique to estimate the shape, size and location of the non-stationary region boundaries, expressed as coefficients of truncated Fourier series, inside an object domain using electrical impedance tomography. The conductivity of the object domain is assumed to be known a priori. <span class="hlt">Dynamic</span> OBBO is a novel addition to the family of <span class="hlt">dynamic</span> evolutionary algorithms. Moreover, it is the first such study on the application of <span class="hlt">dynamic</span> evolutionary algorithms for <span class="hlt">dynamic</span> electrical impedance tomography-based image reconstruction. The performance of the algorithm is tested through numerical simulations and experimental study and is compared with state-of-the-art gradient-based extended Kalman filter. The <span class="hlt">dynamic</span> OBBO is shown to be far superior compared to the extended Kalman filter. It is found to be robust to measurement noise as well as the initial guess, and does not rely on a priori knowledge of the state evolution model. PMID:27203482</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004PhRvA..69e3408S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004PhRvA..69e3408S"><span id="translatedtitle"><span class="hlt">Optimal</span> control of quantum dissipative <span class="hlt">dynamics</span>: Analytic solution for cooling the three-level Λ system</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sklarz, Shlomo E.; Tannor, David J.; Khaneja, Navin</p> <p>2004-05-01</p> <p>We study the problem of <span class="hlt">optimal</span> control of dissipative quantum <span class="hlt">dynamics</span>. Although under most circumstances dissipation leads to an increase in entropy (or a decrease in purity) of the system, there is an important class of problems for which dissipation with external control can decrease the entropy (or increase the purity) of the system. An important example is laser cooling. In such systems, there is an interplay of the Hamiltonian part of the <span class="hlt">dynamics</span>, which is controllable, and the dissipative part of the <span class="hlt">dynamics</span>, which is uncontrollable. The strategy is to control the Hamiltonian portion of the evolution in such a way that the dissipation causes the purity of the system to increase rather than decrease. The goal of this paper is to find the strategy that leads to maximal purity at the final time. Under the assumption that Hamiltonian control is complete and arbitrarily fast, we provide a general framework by which to calculate <span class="hlt">optimal</span> cooling strategies. These assumptions lead to a great simplification, in which the control problem can be reformulated in terms of the spectrum of eigenvalues of ρ , rather than ρ itself. By combining this formulation with the Hamilton-Jacobi-Bellman theorem we are able to obtain an equation for the globally <span class="hlt">optimal</span> cooling strategy in terms of the spectrum of the density matrix. For the three-level Λ system, we provide a complete analytic solution for the <span class="hlt">optimal</span> cooling strategy. For this system it is found that the <span class="hlt">optimal</span> strategy does not exploit system coherences and is a “greedy” strategy, in which the purity is increased maximally at each instant.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20643640','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20643640"><span id="translatedtitle"><span class="hlt">Optimal</span> control of quantum dissipative <span class="hlt">dynamics</span>: Analytic solution for cooling the three-level {lambda} system</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sklarz, Shlomo E.; Tannor, David J.; Khaneja, Navin</p> <p>2004-05-01</p> <p>We study the problem of <span class="hlt">optimal</span> control of dissipative quantum <span class="hlt">dynamics</span>. Although under most circumstances dissipation leads to an increase in entropy (or a decrease in purity) of the system, there is an important class of problems for which dissipation with external control can decrease the entropy (or increase the purity) of the system. An important example is laser cooling. In such systems, there is an interplay of the Hamiltonian part of the <span class="hlt">dynamics</span>, which is controllable, and the dissipative part of the <span class="hlt">dynamics</span>, which is uncontrollable. The strategy is to control the Hamiltonian portion of the evolution in such a way that the dissipation causes the purity of the system to increase rather than decrease. The goal of this paper is to find the strategy that leads to maximal purity at the final time. Under the assumption that Hamiltonian control is complete and arbitrarily fast, we provide a general framework by which to calculate <span class="hlt">optimal</span> cooling strategies. These assumptions lead to a great simplification, in which the control problem can be reformulated in terms of the spectrum of eigenvalues of {rho}, rather than {rho} itself. By combining this formulation with the Hamilton-Jacobi-Bellman theorem we are able to obtain an equation for the globally <span class="hlt">optimal</span> cooling strategy in terms of the spectrum of the density matrix. For the three-level {lambda} system, we provide a complete analytic solution for the <span class="hlt">optimal</span> cooling strategy. For this system it is found that the <span class="hlt">optimal</span> strategy does not exploit system coherences and is a 'greedy' strategy, in which the purity is increased maximally at each instant.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1034620','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1034620"><span id="translatedtitle">Performance monitoring for new phase <span class="hlt">dynamic</span> <span class="hlt">optimization</span> of instruction dispatch cluster configuration</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Balasubramonian, Rajeev; Dwarkadas, Sandhya; Albonesi, David</p> <p>2012-01-24</p> <p>In a processor having multiple clusters which operate in parallel, the number of clusters in use can be varied <span class="hlt">dynamically</span>. At the start of each program phase, the configuration option for an interval is run to determine the <span class="hlt">optimal</span> configuration, which is used until the next phase change is detected. The optimum instruction interval is determined by starting with a minimum interval and doubling it until a low stability factor is reached.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930029136&hterms=papadopoulos&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dpapadopoulos','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930029136&hterms=papadopoulos&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dpapadopoulos"><span id="translatedtitle"><span class="hlt">Optimal</span> control study for the Space Station Solar <span class="hlt">Dynamic</span> power module</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Papadopoulos, P. M.; Laub, A. J.; Kenney, C. S.; Pandey, P.; Ianculescu, G.; Ly, J.</p> <p>1991-01-01</p> <p>The authors present the design of an <span class="hlt">optimal</span> control system for the Space Station Freedom's Solar <span class="hlt">Dynamic</span> Fine Pointing and Tracking (SDFPT) module. A very large state model of six rigid body modes and 272 flexible modes is used in conjunction with classical LQG <span class="hlt">optimal</span> control to produce a full-order controller which satisfies the requirements. The results obtained are compared with those of a classically designed PID (proportional plus integral plus derivative) controller that was implemented for a six-rigid-body-mode forty-flexible-mode model. A major difficulty with designing LQG controllers for large models is solving the Riccati equation that arises from the <span class="hlt">optimal</span> formulation. A Riccati solver based on a Pade approximation to the matrix sign function is used. A symmetric version of this algorithm is derived for the special class of Hamiltonion matrices, thereby yielding, for large problems, a nearly twofold speed increase over a previous algorithm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010PhyE...42..432G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010PhyE...42..432G"><span id="translatedtitle">Shaking the condensates: <span class="hlt">Optimal</span> number squeezing in the <span class="hlt">dynamic</span> splitting of a Bose-Einstein condensate</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Grond, Julian; Schmiedmayer, Jörg; Hohenester, Ulrich</p> <p>2010-01-01</p> <p>We apply <span class="hlt">optimal</span> control theory to the <span class="hlt">dynamic</span> splitting process of a Bose-Einstein condensate (BEC). Number squeezing of two spatially separated BECs is important for interferometry applications and inhibits phase diffusion due to the nonlinear atom-atom interactions. We show how <span class="hlt">optimal</span> number squeezing can be obtained on time scales much shorter compared to adiabatic splitting. The non-adiabatic time evolution of the condensates is controlled via the trap geometry, thus making our control schemes directly applicable to experiments. We find that the <span class="hlt">optimal</span> solution for the trap is oscillatory, where a counterintuitive shaking during the ramp produces highly squeezed states. The underlying process can be identified as a parametric amplification.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012PhDT........42N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012PhDT........42N"><span id="translatedtitle">Nonlinear Modeling, <span class="hlt">Dynamic</span> Analysis, and <span class="hlt">Optimal</span> Design and Operation of Electromechanical Valve Systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Naseradinmousavi, Peiman</p> <p></p> <p>In this dissertation, the actuator-valve systems as a critical part of the automation system are analyzed. Using physics-based high fidelity modeling, this research provides a set of tools to help understand, predict, <span class="hlt">optimize</span>, and control the real performance of these complex systems. The work carried out is expected to add to the suite of analytical and numerical tools that are essential for the development of highly automated ship systems. We present an accurate <span class="hlt">dynamic</span> model, perform nonlinear analysis, and develop <span class="hlt">optimal</span> design and operation for electromechanical valve systems. The mathematical model derived includes electromagnetics, fluid mechanics, and mechanical <span class="hlt">dynamics</span>. Nondimensionalization has been carried out in order to reduce the large number of parameters to a few critical independent sets to help carry out a parametric analysis. The system stability analysis is then carried out with the aid of the tools from nonlinear <span class="hlt">dynamic</span> analysis. This reveals that the system is unstable in a certain region of the parameter space. The system is also shown to exhibit crisis and transient chaotic responses. Smart valves are often operated under local power supply (for various mission-critical reasons) and need to consume as little energy as possible in order to ensure continued operability. The Simulated Annealing (SA) algorithm is utilized to <span class="hlt">optimize</span> the actuation subsystem yielding the most efficient configuration from the point of view of energy consumption for two sets of design variables. The <span class="hlt">optimization</span> is particularly important when the smart valves are used in a distributed network. Another aspect of <span class="hlt">optimality</span> is more subtle and concerns <span class="hlt">optimal</span> operation given a designed system. <span class="hlt">Optimal</span> operation comes after the <span class="hlt">optimal</span> design process to explore if there is any particular method of the valve operation that would yield the minimum possible energy used. The results of our model developed are also validated with the aid of an experimental setup including an electrically actuated butterfly valve. Several pressure sensors are employed to measure the pressure drop across the valve in addition to a torque sensor to determine the total torque acting on the valve motion.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4784908','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4784908"><span id="translatedtitle"><span class="hlt">Dynamical</span> Allocation of Cellular Resources as an <span class="hlt">Optimal</span> Control Problem: Novel Insights into Microbial Growth Strategies</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Giordano, Nils; Mairet, Francis; Gouzé, Jean-Luc</p> <p>2016-01-01</p> <p>Microbial physiology exhibits growth laws that relate the macromolecular composition of the cell to the growth rate. Recent work has shown that these empirical regularities can be derived from coarse-grained models of resource allocation. While these studies focus on steady-state growth, such conditions are rarely found in natural habitats, where microorganisms are continually challenged by environmental fluctuations. The aim of this paper is to extend the study of microbial growth strategies to <span class="hlt">dynamical</span> environments, using a self-replicator model. We formulate <span class="hlt">dynamical</span> growth maximization as an <span class="hlt">optimal</span> control problem that can be solved using Pontryagin’s Maximum Principle. We compare this theoretical gold standard with different possible implementations of growth control in bacterial cells. We find that simple control strategies enabling growth-rate maximization at steady state are suboptimal for transitions from one growth regime to another, for example when shifting bacterial cells to a medium supporting a higher growth rate. A near-<span class="hlt">optimal</span> control strategy in <span class="hlt">dynamical</span> conditions is shown to require information on several, rather than a single physiological variable. Interestingly, this strategy has structural analogies with the regulation of ribosomal protein synthesis by ppGpp in the enterobacterium Escherichia coli. It involves sensing a mismatch between precursor and ribosome concentrations, as well as the adjustment of ribosome synthesis in a switch-like manner. Our results show how the capability of regulatory systems to integrate information about several physiological variables is critical for <span class="hlt">optimizing</span> growth in a changing environment. PMID:26958858</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26958858','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26958858"><span id="translatedtitle"><span class="hlt">Dynamical</span> Allocation of Cellular Resources as an <span class="hlt">Optimal</span> Control Problem: Novel Insights into Microbial Growth Strategies.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Giordano, Nils; Mairet, Francis; Gouzé, Jean-Luc; Geiselmann, Johannes; de Jong, Hidde</p> <p>2016-03-01</p> <p>Microbial physiology exhibits growth laws that relate the macromolecular composition of the cell to the growth rate. Recent work has shown that these empirical regularities can be derived from coarse-grained models of resource allocation. While these studies focus on steady-state growth, such conditions are rarely found in natural habitats, where microorganisms are continually challenged by environmental fluctuations. The aim of this paper is to extend the study of microbial growth strategies to <span class="hlt">dynamical</span> environments, using a self-replicator model. We formulate <span class="hlt">dynamical</span> growth maximization as an <span class="hlt">optimal</span> control problem that can be solved using Pontryagin's Maximum Principle. We compare this theoretical gold standard with different possible implementations of growth control in bacterial cells. We find that simple control strategies enabling growth-rate maximization at steady state are suboptimal for transitions from one growth regime to another, for example when shifting bacterial cells to a medium supporting a higher growth rate. A near-<span class="hlt">optimal</span> control strategy in <span class="hlt">dynamical</span> conditions is shown to require information on several, rather than a single physiological variable. Interestingly, this strategy has structural analogies with the regulation of ribosomal protein synthesis by ppGpp in the enterobacterium Escherichia coli. It involves sensing a mismatch between precursor and ribosome concentrations, as well as the adjustment of ribosome synthesis in a switch-like manner. Our results show how the capability of regulatory systems to integrate information about several physiological variables is critical for <span class="hlt">optimizing</span> growth in a changing environment. PMID:26958858</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/15387250','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/15387250"><span id="translatedtitle">A noisy self-organizing neural network with bifurcation <span class="hlt">dynamics</span> for combinatorial <span class="hlt">optimization</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kwok, Terence; Smith, Kate A</p> <p>2004-01-01</p> <p>The self-organizing neural network (SONN) for solving general "0-1" combinatorial <span class="hlt">optimization</span> problems (COPs) is studied in this paper, with the aim of overcoming existing limitations in convergence and solution quality. This is achieved by incorporating two main features: an efficient weight normalization process exhibiting bifurcation <span class="hlt">dynamics</span>, and neurons with additive noise. The SONN is studied both theoretically and experimentally by using the N-queen problem as an example to demonstrate and explain the dependence of <span class="hlt">optimization</span> performance on annealing schedules and other system parameters. An equilibrium model of the SONN with neuronal weight normalization is derived, which explains observed bands of high feasibility in the normalization parameter space in terms of bifurcation <span class="hlt">dynamics</span> of the normalization process, and provides insights into the roles of different parameters in the <span class="hlt">optimization</span> process. Under certain conditions, this <span class="hlt">dynamical</span> systems view of the SONN reveals cascades of period-doubling bifurcations to chaos occurring in multidimensional space with the annealing temperature as the bifurcation parameter. A strange attractor in the two-dimensional (2-D) case is also presented. Furthermore, by adding random noise to the cost potentials of the network nodes, it is demonstrated that unwanted oscillations between symmetrical and "greedy" nodes can be sufficiently reduced, resulting in higher solution quality and feasibility. PMID:15387250</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SPIE.9501E..0YM','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SPIE.9501E..0YM"><span id="translatedtitle"><span class="hlt">Optimizing</span> meridional advection of the Advanced Research WRF (ARW) <span class="hlt">dynamics</span> for Intel Xeon Phi coprocessor</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mielikainen, Jarno; Huang, Bormin; Huang, Allen H.-L.</p> <p>2015-05-01</p> <p>The most widely used community weather forecast and research model in the world is the Weather Research and Forecast (WRF) model. Two distinct varieties of WRF exist. The one we are interested is the Advanced Research WRF (ARW) is an experimental, advanced research version featuring very high resolution. The WRF Nonhydrostatic Mesoscale Model (WRF-NMM) has been designed for forecasting operations. WRF consists of <span class="hlt">dynamics</span> code and several physics modules. The WRF-ARW core is based on an Eulerian solver for the fully compressible nonhydrostatic equations. In the paper, we <span class="hlt">optimize</span> a meridional (north-south direction) advection subroutine for Intel Xeon Phi coprocessor. Advection is of the most time consuming routines in the ARW <span class="hlt">dynamics</span> core. It advances the explicit perturbation horizontal momentum equations by adding in the large-timestep tendency along with the small timestep pressure gradient tendency. We will describe the challenges we met during the development of a high-speed <span class="hlt">dynamics</span> code subroutine for MIC architecture. Furthermore, lessons learned from the code <span class="hlt">optimization</span> process will be discussed. The results show that the <span class="hlt">optimizations</span> improved performance of the original code on Xeon Phi 7120P by a factor of 1.2x.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014SPIE.9247E..0MM','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014SPIE.9247E..0MM"><span id="translatedtitle"><span class="hlt">Optimizing</span> zonal advection of the Advanced Research WRF (ARW) <span class="hlt">dynamics</span> for Intel MIC</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mielikainen, Jarno; Huang, Bormin; Huang, Allen H.</p> <p>2014-10-01</p> <p>The Weather Research and Forecast (WRF) model is the most widely used community weather forecast and research model in the world. There are two distinct varieties of WRF. The Advanced Research WRF (ARW) is an experimental, advanced research version featuring very high resolution. The WRF Nonhydrostatic Mesoscale Model (WRF-NMM) has been designed for forecasting operations. WRF consists of <span class="hlt">dynamics</span> code and several physics modules. The WRF-ARW core is based on an Eulerian solver for the fully compressible nonhydrostatic equations. In the paper, we will use Intel Intel Many Integrated Core (MIC) architecture to substantially increase the performance of a zonal advection subroutine for <span class="hlt">optimization</span>. It is of the most time consuming routines in the ARW <span class="hlt">dynamics</span> core. Advection advances the explicit perturbation horizontal momentum equations by adding in the large-timestep tendency along with the small timestep pressure gradient tendency. We will describe the challenges we met during the development of a high-speed <span class="hlt">dynamics</span> code subroutine for MIC architecture. Furthermore, lessons learned from the code <span class="hlt">optimization</span> process will be discussed. The results show that the <span class="hlt">optimizations</span> improved performance of the original code on Xeon Phi 5110P by a factor of 2.4x.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AIPC.1103..622L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AIPC.1103..622L"><span id="translatedtitle">Computer Program for Analysis, Design and <span class="hlt">Optimization</span> of Propulsion, <span class="hlt">Dynamics</span>, and Kinematics of Multistage Rockets</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lali, Mehdi</p> <p>2009-03-01</p> <p>A comprehensive computer program is designed in MATLAB to analyze, design and <span class="hlt">optimize</span> the propulsion, <span class="hlt">dynamics</span>, thermodynamics, and kinematics of any serial multi-staging rocket for a set of given data. The program is quite user-friendly. It comprises two main sections: "analysis and design" and "<span class="hlt">optimization</span>." Each section has a GUI (Graphical User Interface) in which the rocket's data are entered by the user and by which the program is run. The first section analyzes the performance of the rocket that is previously devised by the user. Numerous plots and subplots are provided to display the performance of the rocket. The second section of the program finds the "optimum trajectory" via billions of iterations and computations which are done through sophisticated algorithms using numerical methods and incremental integrations. Innovative techniques are applied to calculate the <span class="hlt">optimal</span> parameters for the engine and designing the "<span class="hlt">optimal</span> pitch program." This computer program is stand-alone in such a way that it calculates almost every design parameter in regards to rocket propulsion and <span class="hlt">dynamics</span>. It is meant to be used for actual launch operations as well as educational and research purposes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19910065131&hterms=Cybernetic+Augmentation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DCybernetic%2BAugmentation','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19910065131&hterms=Cybernetic+Augmentation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DCybernetic%2BAugmentation"><span id="translatedtitle"><span class="hlt">Optimal</span> discrete-time <span class="hlt">dynamic</span> output-feedback design - A w-domain approach</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ha, Cheolkeun; Ly, Uy-Loi</p> <p>1991-01-01</p> <p>An alternative method for <span class="hlt">optimal</span> digital control design is described in this paper. The method is based on the usage of the w-transform and has many attractive design features. One of these is its immediate connection with frequency loop-shaping techniques that are now popular and effective for multivariable control synthesis in continuous-time domain. Furthermore, any design algorithms originally developed for continuous-time systems can now be immediately extended to the discrete-time domain. The main results presented in this paper are the exact problem formulation and solution of an <span class="hlt">optimal</span> discrete-time <span class="hlt">dynamic</span> output-feedback design in the w-domain involving a quadratic performance index to random disturbances. In addition, necessary conditions for <span class="hlt">optimality</span> are obtained for the numerical solution of the <span class="hlt">optimal</span> output-feedback compensator design. A numerical example is presented illustrating its application to the design of a low-order <span class="hlt">dynamic</span> compensator in a stability augmentation system of a commercial transport.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011WRR....47.0G08G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011WRR....47.0G08G"><span id="translatedtitle"><span class="hlt">Optimal</span> <span class="hlt">dynamic</span> water allocation: Irrigation extractions and environmental tradeoffs in the Murray River, Australia</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Grafton, R. Quentin; Chu, Hoang Long; Stewardson, Michael; Kompas, Tom</p> <p>2011-12-01</p> <p>A key challenge in managing semiarid basins, such as in the Murray-Darling in Australia, is to balance the trade-offs between the net benefits of allocating water for irrigated agriculture, and other uses, versus the costs of reduced surface flows for the environment. Typically, water planners do not have the tools to <span class="hlt">optimally</span> and <span class="hlt">dynamically</span> allocate water among competing uses. We address this problem by developing a general stochastic, <span class="hlt">dynamic</span> programming model with four state variables (the drought status, the current weather, weather correlation, and current storage) and two controls (environmental release and irrigation allocation) to <span class="hlt">optimally</span> allocate water between extractions and in situ uses. The model is calibrated to Australia's Murray River that generates: (1) a robust qualitative result that "pulse" or artificial flood events are an <span class="hlt">optimal</span> way to deliver environmental flows over and above conveyance of base flows; (2) from 2001 to 2009 a water reallocation that would have given less to irrigated agriculture and more to environmental flows would have generated between half a billion and over 3 billion U.S. dollars in overall economic benefits; and (3) water markets increase <span class="hlt">optimal</span> environmental releases by reducing the losses associated with reduced water diversions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1998PhDT.......106T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1998PhDT.......106T"><span id="translatedtitle">Experimental/analytical approaches to modeling, calibrating and <span class="hlt">optimizing</span> shaking table <span class="hlt">dynamics</span> for structural <span class="hlt">dynamic</span> applications</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Trombetti, Tomaso</p> <p></p> <p>This thesis presents an Experimental/Analytical approach to modeling and calibrating shaking tables for structural <span class="hlt">dynamic</span> applications. This approach was successfully applied to the shaking table recently built in the structural laboratory of the Civil Engineering Department at Rice University. This shaking table is capable of reproducing model earthquake ground motions with a peak acceleration of 6 g's, a peak velocity of 40 inches per second, and a peak displacement of 3 inches, for a maximum payload of 1500 pounds. It has a frequency bandwidth of approximately 70 Hz and is designed to test structural specimens up to 1/5 scale. The rail/table system is mounted on a reaction mass of about 70,000 pounds consisting of three 12 ft x 12 ft x 1 ft reinforced concrete slabs, post-tensioned together and connected to the strong laboratory floor. The slip table is driven by a hydraulic actuator governed by a 407 MTS controller which employs a proportional-integral-derivative-feedforward-differential pressure algorithm to control the actuator displacement. Feedback signals are provided by two LVDT's (monitoring the slip table relative displacement and the servovalve main stage spool position) and by one differential pressure transducer (monitoring the actuator force). The <span class="hlt">dynamic</span> actuator-foundation-specimen system is modeled and analyzed by combining linear control theory and linear structural <span class="hlt">dynamics</span>. The analytical model developed accounts for the effects of actuator oil compressibility, oil leakage in the actuator, time delay in the response of the servovalve spool to a given electrical signal, foundation flexibility, and <span class="hlt">dynamic</span> characteristics of multi-degree-of-freedom specimens. In order to study the actual <span class="hlt">dynamic</span> behavior of the shaking table, the transfer function between target and actual table accelerations were identified using experimental results and spectral estimation techniques. The power spectral density of the system input and the cross power spectral density of the table input and output were estimated using the Bartlett's spectral estimation method. The experimentally-estimated table acceleration transfer functions obtained for different working conditions are correlated with their analytical counterparts. As a result of this comprehensive correlation study, a thorough understanding of the shaking table <span class="hlt">dynamics</span> and its sensitivities to control and payload parameters is obtained. Moreover, the correlation study leads to a calibrated analytical model of the shaking table of high predictive ability. It is concluded that, in its present conditions, the Rice shaking table is able to reproduce, with a high degree of accuracy, model earthquake accelerations time histories in the frequency bandwidth from 0 to 75 Hz. Furthermore, the exhaustive analysis performed indicates that the table transfer function is not significantly affected by the presence of a large (in terms of weight) payload with a fundamental frequency up to 20 Hz. Payloads having a higher fundamental frequency do affect significantly the shaking table performance and require a modification of the table control gain setting that can be easily obtained using the predictive analytical model of the shaking table. The complete description of a structural <span class="hlt">dynamic</span> experiment performed using the Rice shaking table facility is also reported herein. The object of this experimentation was twofold: (1) to verify the testing capability of the shaking table and, (2) to experimentally validate a simplified theory developed by the author, which predicts the maximum rotational response developed by seismic isolated building structures characterized by non-coincident centers of mass and rigidity, when subjected to strong earthquake ground motions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JHyd..533..213Q','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JHyd..533..213Q"><span id="translatedtitle">Quantifying <span class="hlt">dynamic</span> sensitivity of <span class="hlt">optimization</span> algorithm parameters to improve hydrological model calibration</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Qi, Wei; Zhang, Chi; Fu, Guangtao; Zhou, Huicheng</p> <p>2016-02-01</p> <p>It is widely recognized that <span class="hlt">optimization</span> algorithm parameters have significant impacts on algorithm performance, but quantifying the influence is very complex and difficult due to high computational demands and <span class="hlt">dynamic</span> nature of search parameters. The overall aim of this paper is to develop a global sensitivity analysis based framework to <span class="hlt">dynamically</span> quantify the individual and interactive influence of algorithm parameters on algorithm performance. A variance decomposition sensitivity analysis method, Analysis of Variance (ANOVA), is used for sensitivity quantification, because it is capable of handling small samples and more computationally efficient compared with other approaches. The Shuffled Complex Evolution method developed at the University of Arizona algorithm (SCE-UA) is selected as an <span class="hlt">optimization</span> algorithm for investigation, and two criteria, i.e., convergence speed and success rate, are used to measure the performance of SCE-UA. Results show the proposed framework can effectively reveal the <span class="hlt">dynamic</span> sensitivity of algorithm parameters in the search processes, including individual influences of parameters and their interactive impacts. Interactions between algorithm parameters have significant impacts on SCE-UA performance, which has not been reported in previous research. The proposed framework provides a means to understand the <span class="hlt">dynamics</span> of algorithm parameter influence, and highlights the significance of considering interactive parameter influence to improve algorithm performance in the search processes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4111489','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4111489"><span id="translatedtitle">Adaptive <span class="hlt">Dynamic</span> Range <span class="hlt">Optimization</span> (ADRO): A Digital Amplification Strategy for Hearing Aids and Cochlear Implants</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Blamey, Peter J.</p> <p>2005-01-01</p> <p>Adaptive <span class="hlt">dynamic</span> range <span class="hlt">optimization</span> (ADRO) is an amplification strategy that uses digital signal processing techniques to improve the audibility, comfort, and intelligibility of sounds for people who use cochlear implants and/or hearing aids. The strategy uses statistical analysis to select the most information-rich section of the input <span class="hlt">dynamic</span> range in multiple-frequency channels. Fuzzy logic rules control the gain in each frequency channel so that the selected section of the <span class="hlt">dynamic</span> range is presented at an audible and comfortable level. The ADRO processing thus adaptively <span class="hlt">optimizes</span> the <span class="hlt">dynamic</span> range of the signal in multiple-frequency channels. Clinical studies show that ADRO can be fitted easily to all degrees of hearing loss for hearing aids and cochlear implants in a direct and intuitive manner, taking the preferences of the listener into account. The result is high acceptance by new and experienced hearing aid users and strong preferences for ADRO compared with alternative amplification strategies. The ADRO processing is particularly well suited to bimodal and hybrid stimulation which combine electric and acoustic stimulation in opposite ears or in the same ear, respectively. PMID:16012705</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/11542561','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/11542561"><span id="translatedtitle"><span class="hlt">Dynamic</span> <span class="hlt">optimization</span> of CELSS crop photosynthetic rate by computer-assisted feedback control.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chun, C; Mitchell, C A</p> <p>1997-01-01</p> <p>A procedure for <span class="hlt">dynamic</span> <span class="hlt">optimization</span> of net photosynthetic rate (Pn) for crop production in Controlled Ecological Life-Support Systems (CELSS) was developed using leaf lettuce as a model crop. Canopy Pn was measured in real time and fed back for environmental control. Setpoints of photosynthetic photon flux (PPF) and CO2 concentration for each hour of the crop-growth cycle were decided by computer to reach a targeted Pn each day. Decision making was based on empirical mathematical models combined with rule sets developed from recent experimental data. Comparisons showed that <span class="hlt">dynamic</span> control resulted in better yield per unit energy input to the growth system than did static control. With comparable productivity parameters and potential for significant energy savings, <span class="hlt">dynamic</span> control strategies will contribute greatly to the sustainability of space-deployed CELSS. PMID:11542561</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3935827','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3935827"><span id="translatedtitle">Game Theory and Extremal <span class="hlt">Optimization</span> for Community Detection in Complex <span class="hlt">Dynamic</span> Networks</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Lung, Rodica Ioana; Chira, Camelia; Andreica, Anca</p> <p>2014-01-01</p> <p>The detection of evolving communities in <span class="hlt">dynamic</span> complex networks is a challenging problem that recently received attention from the research community. <span class="hlt">Dynamics</span> clearly add another complexity dimension to the difficult task of community detection. Methods should be able to detect changes in the network structure and produce a set of community structures corresponding to different timestamps and reflecting the evolution in time of network data. We propose a novel approach based on game theory elements and extremal <span class="hlt">optimization</span> to address <span class="hlt">dynamic</span> communities detection. Thus, the problem is formulated as a mathematical game in which nodes take the role of players that seek to choose a community that maximizes their profit viewed as a fitness function. Numerical results obtained for both synthetic and real-world networks illustrate the competitive performance of this game theoretical approach. PMID:24586257</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/654204','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/654204"><span id="translatedtitle">A multi-objective <span class="hlt">dynamic</span> programming approach to constrained discrete-time <span class="hlt">optimal</span> control</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Driessen, B.J.; Kwok, K.S.</p> <p>1997-09-01</p> <p>This work presents a multi-objective differential <span class="hlt">dynamic</span> programming approach to constrained discrete-time <span class="hlt">optimal</span> control. In the backward sweep of the <span class="hlt">dynamic</span> programming in the quadratic sub problem, the sub problem input at a stage or time step is solved for in terms of the sub problem state entering that stage so as to minimize the summed immediate and future cost subject to minimizing the summed immediate and future constraint violations, for all such entering states. The method differs from previous <span class="hlt">dynamic</span> programming methods, which used penalty methods, in that the constraints of the sub problem, which may include terminal constraints and path constraints, are solved exactly if they are solvable; otherwise, their total violation is minimized. Again, the resulting solution of the sub problem is an input history that minimizes the quadratic cost function subject to being a minimizer of the total constraint violation. The expected quadratic convergence of the proposed algorithm is demonstrated on a numerical example.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25725122','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25725122"><span id="translatedtitle">A differentiable reformulation for E-<span class="hlt">optimal</span> design of experiments in nonlinear <span class="hlt">dynamic</span> biosystems.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Telen, Dries; Van Riet, Nick; Logist, Flip; Van Impe, Jan</p> <p>2015-06-01</p> <p>Informative experiments are highly valuable for estimating parameters in nonlinear <span class="hlt">dynamic</span> bioprocesses. Techniques for <span class="hlt">optimal</span> experiment design ensure the systematic design of such informative experiments. The E-criterion which can be used as objective function in <span class="hlt">optimal</span> experiment design requires the maximization of the smallest eigenvalue of the Fisher information matrix. However, one problem with the minimal eigenvalue function is that it can be nondifferentiable. In addition, no closed form expression exists for the computation of eigenvalues of a matrix larger than a 4 by 4 one. As eigenvalues are normally computed with iterative methods, state-of-the-art <span class="hlt">optimal</span> control solvers are not able to exploit automatic differentiation to compute the derivatives with respect to the decision variables. In the current paper a reformulation strategy from the field of convex <span class="hlt">optimization</span> is suggested to circumvent these difficulties. This reformulation requires the inclusion of a matrix inequality constraint involving positive semidefiniteness. In this paper, this positive semidefiniteness constraint is imposed via Sylverster's criterion. As a result the maximization of the minimum eigenvalue function can be formulated in standard <span class="hlt">optimal</span> control solvers through the addition of nonlinear constraints. The presented methodology is successfully illustrated with a case study from the field of predictive microbiology. PMID:25725122</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008APS..MARP26001W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008APS..MARP26001W"><span id="translatedtitle">Use of Ultrafast Molecular <span class="hlt">Dynamics</span> and <span class="hlt">Optimal</span> Control for Identifying Biomolecules</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wolf, Jean-Pierre</p> <p>2008-03-01</p> <p>With F.COURVOISIER,L.GUYON,V.BOUTOU, and M.ROTH,J. ROSLUND, H. RABITZ, Princeton University. The identification and discrimination of molecules that exhibit almost identical structures and spectra using fluorescence spectroscopy is considered quite difficult. In order to evaluate the capability of <span class="hlt">optimal</span> control for discriminating between the optical emissions of nearly identical molecules, we developed a new approach called ``<span class="hlt">optimal</span> <span class="hlt">dynamic</span> discrimination (ODD). A proof of principle ODD experiment has been performed using Riboflavin (RBF) and Flavin Mononucleotide (FMN) as model system. We used a complex multipulse control field made of a pair of pulses (UV and IR). The UV part (400 nm) is <span class="hlt">optimally</span> shaped using a control learning loop while the IR component (800 nm) is FT-limited (100 fs) and set at a definite time delay with respect to the UV pulse. Clear discrimination was observed for <span class="hlt">optimally</span> shaped pulses, although the linear spectra from both molecules are virtually identical. A further experiment showed that, by using the <span class="hlt">optimal</span> pulse shapes that maximize the fluorescence depletion in FMN and RBF in a differential manner, the concentration of both molecules could be retrieved while they were mixed in the same solution. The ODD demonstration sets out a promising path for future applications, as for example fluorescence microscopy where endogenous fluorescence spectra of many biomolecules overlap.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011NTA.....2..497I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011NTA.....2..497I"><span id="translatedtitle">A hybrid approach using chaotic <span class="hlt">dynamics</span> and global search algorithms for combinatorial <span class="hlt">optimization</span> problems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Igeta, Hideki; Hasegawa, Mikio</p> <p></p> <p>Chaotic <span class="hlt">dynamics</span> have been effectively applied to improve various heuristic algorithms for combinatorial <span class="hlt">optimization</span> problems in many studies. Currently, the most used chaotic <span class="hlt">optimization</span> scheme is to drive heuristic solution search algorithms applicable to large-scale problems by chaotic neurodynamics including the tabu effect of the tabu search. Alternatively, meta-heuristic algorithms are used for combinatorial <span class="hlt">optimization</span> by combining a neighboring solution search algorithm, such as tabu, gradient, or other search method, with a global search algorithm, such as genetic algorithms (GA), ant colony <span class="hlt">optimization</span> (ACO), or others. In these hybrid approaches, the ACO has effectively <span class="hlt">optimized</span> the solution of many benchmark problems in the quadratic assignment problem library. In this paper, we propose a novel hybrid method that combines the effective chaotic search algorithm that has better performance than the tabu search and global search algorithms such as ACO and GA. Our results show that the proposed chaotic hybrid algorithm has better performance than the conventional chaotic search and conventional hybrid algorithms. In addition, we show that chaotic search algorithm combined with ACO has better performance than when combined with GA.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/17025540','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/17025540"><span id="translatedtitle">Development of <span class="hlt">optimal</span> models of porous media by combining static and <span class="hlt">dynamic</span> data: the porosity distribution.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hamzehpour, Hossein; Sahimi, Muhammad</p> <p>2006-08-01</p> <p>This paper is part of a project, the goal of which is the development of the <span class="hlt">optimal</span> spatial distributions of the porosity and permeability of a large-scale porous medium by using complementary static and <span class="hlt">dynamic</span> data for the medium. The data include limited measurements of the porosity, which the method honors (preserves) in the <span class="hlt">optimal</span> model and utilizes its correlation function, together with the first-arrival (FA) times, at a certain number of receivers, of seismic waves that have propagated in the medium and the time dependence of the pressure of a fluid flowing in the medium. The method uses the simulated-annealing (SA) technique in order to develop the <span class="hlt">optimal</span> model. In the present paper we utilize the porosity and FA times data in order to develop the <span class="hlt">optimal</span> spatial distribution of the porosity. This is accomplished by combining the SA method with a simulator that solves for the numerical solution of the acoustic-wave equation from which the FA times are estimated, limited porosity, and FA times data. We show that the <span class="hlt">optimal</span> model not only honors the data, but also provides accurate estimates of the porosities in the rest of the porous medium. The efficiency of the computations is discussed in detail. PMID:17025540</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JSV...335...55C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JSV...335...55C"><span id="translatedtitle">H∞ <span class="hlt">optimization</span> of <span class="hlt">dynamic</span> vibration absorber variant for vibration control of damped linear systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chun, Semin; Lee, Youngil; Kim, Tae-Hyoung</p> <p>2015-01-01</p> <p>This study focuses on the H∞ <span class="hlt">optimal</span> design of a <span class="hlt">dynamic</span> vibration absorber (DVA) variant for suppressing high-amplitude vibrations of damped primary systems. Unlike traditional DVA configurations, the damping element in this type of DVA is connected directly to the ground instead of the primary mass. First, a thorough graphical analysis of the variations in the maximum amplitude magnification factor depending on two design parameters, natural frequency and absorber damping ratios, is performed. The results of this analysis clearly show that any fixed-points-theory-based conventional method could provide, at best, only locally but not globally <span class="hlt">optimal</span> parameters. Second, for directly handling the H∞ <span class="hlt">optimization</span> for its <span class="hlt">optimal</span> design, a novel meta-heuristic search engine, called the diversity-guided cyclic-network-topology-based constrained particle swarm <span class="hlt">optimization</span> (Div-CNT-CPSO), is developed. The variant DVA system developed using the proposed Div-CNT-CPSO scheme is compared with those reported in the literature. The results of this comparison verified that the proposed system is better than the existing methods for suppressing the steady-state vibration amplitude of a controlled primary system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005PhDT.......111M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005PhDT.......111M"><span id="translatedtitle">Applying <span class="hlt">dynamic</span> wake models to large swirl velocities for <span class="hlt">optimal</span> propellers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Makinen, Stephen M.</p> <p></p> <p>The <span class="hlt">dynamic</span> wake model is applied to the <span class="hlt">optimal</span> propeller systems originally studied by the classic aerodynamicists: Betz, Prandtl and Goldstein. Several modified forms of the model are theoretically developed to extend the applicable range to flight conditions with a large swirl velocity component. <span class="hlt">Dynamic</span> wake model calculations accurately predict the inflow behavior for helicopter rotors, including axial flow for large tip-speed ratios, (OR/V infinity) ≥ 20. The swirl velocity is a prominent component for small tip-speed ratios (≤5), typical of forward flight for tiltrotor craft such as the V-22 Osprey and the BA609. <span class="hlt">Dynamic</span> wake calculation results are compared to the closed-form solutions by Prandtl and Goldstein. The exact and approximate solutions correlate strongly for infinite blade cases and finite blade cases with a large tip-speed ratio. The original form of the He-Peters and Morillo-Peters <span class="hlt">dynamic</span> wake models converge poorly for small tip-speed ratios, due to neglect of the swirl velocity. Derivations are presented for several adaptations of the models to account for the large apparent mass at the inboard blade region. A best modified form is chosen and the associated empirical factor is <span class="hlt">optimized</span> to correlate well with Prandtl's solution. Error norms for the original and modified forms of the <span class="hlt">dynamic</span> wake model are presented for propellers of various number of blades and a range of tip-speed ratios. The Goldstein solution is also studied in depth and conclusions are drawn for improving the <span class="hlt">dynamic</span> wake model.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/18532824','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/18532824"><span id="translatedtitle"><span class="hlt">Optimal</span> control design of NMR and <span class="hlt">dynamic</span> nuclear polarization experiments using monotonically convergent algorithms.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Maximov, Ivan I; Tosner, Zdenĕk; Nielsen, Niels Chr</p> <p>2008-05-14</p> <p><span class="hlt">Optimal</span> control theory has recently been introduced to nuclear magnetic resonance (NMR) spectroscopy as a means to systematically design and <span class="hlt">optimize</span> pulse sequences for liquid- and solid-state applications. This has so far primarily involved numerical <span class="hlt">optimization</span> using gradient-based methods, which allow for the <span class="hlt">optimization</span> of a large number of pulse sequence parameters in a concerted way to maximize the efficiency of transfer between given spin states or shape the nuclear spin Hamiltonian to a particular form, both within a given period of time. Using such tools, a variety of new pulse sequences with improved performance have been developed, and the NMR spin engineers have been challenged to consider alternative routes for analytical experiment design to meet similar performance. In addition, it has lead to increasing demands to the numerical procedures used in the <span class="hlt">optimization</span> process in terms of computational speed and fast convergence. With the latter aspect in mind, here we introduce an alternative approach to numerical experiment design based on the Krotov formulation of <span class="hlt">optimal</span> control theory. For practical reasons, the overall radio frequency power delivered to the sample should be minimized to facilitate experimental implementation and avoid excessive sample heating. The presented algorithm makes explicit use of this requirement and iteratively solves the stationary conditions making sure that the maximum of the objective is reached. It is shown that this method is faster per iteration and takes different paths within a control space than gradient-based methods. In the present work, the Krotov approach is demonstrated by the <span class="hlt">optimization</span> of NMR and <span class="hlt">dynamic</span> nuclear polarization experiments for various spin systems and using different constraints with respect to radio frequency and microwave power consumption. PMID:18532824</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/877137','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/877137"><span id="translatedtitle">Developing a computationally efficient <span class="hlt">dynamic</span> multilevel hybrid <span class="hlt">optimization</span> scheme using multifidelity model interactions.</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hough, Patricia Diane (Sandia National Laboratories, Livermore, CA); Gray, Genetha Anne (Sandia National Laboratories, Livermore, CA); Castro, Joseph Pete Jr.; Giunta, Anthony Andrew</p> <p>2006-01-01</p> <p>Many engineering application problems use <span class="hlt">optimization</span> algorithms in conjunction with numerical simulators to search for solutions. The formulation of relevant objective functions and constraints dictate possible <span class="hlt">optimization</span> algorithms. Often, a gradient based approach is not possible since objective functions and constraints can be nonlinear, nonconvex, non-differentiable, or even discontinuous and the simulations involved can be computationally expensive. Moreover, computational efficiency and accuracy are desirable and also influence the choice of solution method. With the advent and increasing availability of massively parallel computers, computational speed has increased tremendously. Unfortunately, the numerical and model complexities of many problems still demand significant computational resources. Moreover, in <span class="hlt">optimization</span>, these expenses can be a limiting factor since obtaining solutions often requires the completion of numerous computationally intensive simulations. Therefore, we propose a multifidelity <span class="hlt">optimization</span> algorithm (MFO) designed to improve the computational efficiency of an <span class="hlt">optimization</span> method for a wide range of applications. In developing the MFO algorithm, we take advantage of the interactions between multi fidelity models to develop a <span class="hlt">dynamic</span> and computational time saving <span class="hlt">optimization</span> algorithm. First, a direct search method is applied to the high fidelity model over a reduced design space. In conjunction with this search, a specialized oracle is employed to map the design space of this high fidelity model to that of a computationally cheaper low fidelity model using space mapping techniques. Then, in the low fidelity space, an optimum is obtained using gradient or non-gradient based <span class="hlt">optimization</span>, and it is mapped back to the high fidelity space. In this paper, we describe the theory and implementation details of our MFO algorithm. We also demonstrate our MFO method on some example problems and on two applications: earth penetrators and groundwater remediation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AIPC.1440..293J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AIPC.1440..293J"><span id="translatedtitle">Computational fluid <span class="hlt">dynamics</span> based aerodynamic <span class="hlt">optimization</span> of the wind tunnel primary nozzle</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jan, Kolář; Václav, Dvořák</p> <p>2012-06-01</p> <p>The aerodynamic shape <span class="hlt">optimization</span> of the supersonic flat nozzle is the aim of proposed paper. The nozzle discussed, is applied as a primary nozzle of the inlet part of supersonic wind tunnel. Supersonic nozzles of the measure area inlet parts need to guarantee several requirements of flow properties and quality. Mach number and minimal differences between real and required velocity and turbulence profiles at the nozzle exit are the most important parameters to meet. The aerodynamic shape <span class="hlt">optimization</span> of the flat 2D nozzle in Computational Fluid <span class="hlt">Dynamics</span> (CFD) is employed to reach as uniform exit velocity profile as possible, with the mean Mach number 1.4. <span class="hlt">Optimization</span> process does not use any of standard routines of global or local optimum searching. Instead, newly formed routine, which exploits shape-based oriented sequence of nozzles, is used to research within whole discretized parametric space. The movement within <span class="hlt">optimization</span> process is not driven by gradient or evolutionary too, instead, the Path of Minimal Shape Deformation is followed. <span class="hlt">Dynamic</span> mesh approach is used to deform the shape and mesh from the actual nozzle to the subsequent one. <span class="hlt">Dynamic</span> deformation of mesh allows to speed up whole converging process as an initialization of flow at the newly formed mesh is based on afore-computed shape. Shape-based similarity query in field of supersonic nozzles is discussed and applied. Evolutionary technique with genetic algorithm is used to search for minimal deformational path. As a result, the best variant from the set of solved shapes is analyzed at the base of momentum coefficient and desired Mach number at the nozzle exit.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JSP...152..569T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JSP...152..569T"><span id="translatedtitle">An <span class="hlt">Optimization</span> Principle for Deriving Nonequilibrium Statistical Models of Hamiltonian <span class="hlt">Dynamics</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Turkington, Bruce</p> <p>2013-08-01</p> <p>A general method for deriving closed reduced models of Hamiltonian <span class="hlt">dynamical</span> systems is developed using techniques from <span class="hlt">optimization</span> and statistical estimation. Given a vector of resolved variables, selected to describe the macroscopic state of the system, a family of quasi-equilibrium probability densities on phase space corresponding to the resolved variables is employed as a statistical model, and the evolution of the mean resolved vector is estimated by <span class="hlt">optimizing</span> over paths of these densities. Specifically, a cost function is constructed to quantify the lack-of-fit to the microscopic <span class="hlt">dynamics</span> of any feasible path of densities from the statistical model; it is an ensemble-averaged, weighted, squared-norm of the residual that results from submitting the path of densities to the Liouville equation. The path that minimizes the time integral of the cost function determines the best-fit evolution of the mean resolved vector. The closed reduced equations satisfied by the <span class="hlt">optimal</span> path are derived by Hamilton-Jacobi theory. When expressed in terms of the macroscopic variables, these equations have the generic structure of governing equations for nonequilibrium thermodynamics. In particular, the value function for the <span class="hlt">optimization</span> principle coincides with the dissipation potential that defines the relation between thermodynamic forces and fluxes. The adjustable closure parameters in the best-fit reduced equations depend explicitly on the arbitrary weights that enter into the lack-of-fit cost function. Two particular model reductions are outlined to illustrate the general method. In each example the set of weights in the <span class="hlt">optimization</span> principle contracts into a single effective closure parameter.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AMT.....8.3447L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AMT.....8.3447L"><span id="translatedtitle"><span class="hlt">Dynamic</span> statistical <span class="hlt">optimization</span> of GNSS radio occultation bending angles: advanced algorithm and performance analysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Y.; Kirchengast, G.; Scherllin-Pirscher, B.; Norman, R.; Yuan, Y. B.; Fritzer, J.; Schwaerz, M.; Zhang, K.</p> <p>2015-08-01</p> <p>We introduce a new <span class="hlt">dynamic</span> statistical <span class="hlt">optimization</span> algorithm to initialize ionosphere-corrected bending angles of Global Navigation Satellite System (GNSS)-based radio occultation (RO) measurements. The new algorithm estimates background and observation error covariance matrices with geographically varying uncertainty profiles and realistic global-mean correlation matrices. The error covariance matrices estimated by the new approach are more accurate and realistic than in simplified existing approaches and can therefore be used in statistical <span class="hlt">optimization</span> to provide <span class="hlt">optimal</span> bending angle profiles for high-altitude initialization of the subsequent Abel transform retrieval of refractivity. The new algorithm is evaluated against the existing Wegener Center Occultation Processing System version 5.6 (OPSv5.6) algorithm, using simulated data on two test days from January and July 2008 and real observed CHAllenging Minisatellite Payload (CHAMP) and Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) measurements from the complete months of January and July 2008. The following is achieved for the new method's performance compared to OPSv5.6: (1) significant reduction of random errors (standard deviations) of <span class="hlt">optimized</span> bending angles down to about half of their size or more; (2) reduction of the systematic differences in <span class="hlt">optimized</span> bending angles for simulated MetOp data; (3) improved retrieval of refractivity and temperature profiles; and (4) realistically estimated global-mean correlation matrices and realistic uncertainty fields for the background and observations. Overall the results indicate high suitability for employing the new <span class="hlt">dynamic</span> approach in the processing of long-term RO data into a reference climate record, leading to well-characterized and high-quality atmospheric profiles over the entire stratosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000WRR....36.1325C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000WRR....36.1325C"><span id="translatedtitle">A multiple-organic-pollutant simulation/<span class="hlt">optimization</span> model of industrial and municipal wastewater loading to a riverine environment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Carmichael, Jeffrey J.; Strzepek, Kenneth M.</p> <p>2000-05-01</p> <p>A simulation/<span class="hlt">optimization</span> model is developed to demonstrate the need for inclusion of interactive pollutant effects in multiple-pollutant wastewater management, by comparing single- and multiple-pollutant least cost approaches that maintain downstream ambient quality levels. The model chooses biological oxygen demand (BOD), N, and P abatement levels for point sources that minimize the combined wastewater treatment costs of the pollutants in order to achieve chosen ambient quality standards. Nonlinear pollutant interactions result in a nonlinear Jacobian matrix of marginal water quality impacts, creating a nonlinear constraint set. The Jacobian is iteratively updated by the simulation model using iterative solutions from the <span class="hlt">optimization</span> model. The open modeling framework allows other types of programming problems to be solved as well, such as <span class="hlt">mixed</span> <span class="hlt">integer</span> and <span class="hlt">mixed</span> <span class="hlt">integer</span> nonlinear problems. Single- and multiple-pollutant management approaches are applied to a case study of the Nitra River Basin in Slovakia. The regrets resulting from implementing BOD-only or fixed Jacobian solutions are shown, and the robustness of the solution procedure is demonstrated by varying the initial pollution abatement levels.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3120844','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3120844"><span id="translatedtitle">Measuring resetting of brain <span class="hlt">dynamics</span> at epileptic seizures: application of global <span class="hlt">optimization</span> and spatial synchronization techniques</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Sabesan, Shivkumar; Chakravarthy, Niranjan; Tsakalis, Kostas; Pardalos, Panos; Iasemidis, Leon</p> <p>2010-01-01</p> <p>Epileptic seizures are manifestations of intermittent spatiotemporal transitions of the human brain from chaos to order. Measures of chaos, namely maximum Lyapunov exponents (STLmax), from <span class="hlt">dynamical</span> analysis of the electroencephalograms (EEGs) at critical sites of the epileptic brain, progressively converge (diverge) before (after) epileptic seizures, a phenomenon that has been called <span class="hlt">dynamical</span> synchronization (desynchronization). This <span class="hlt">dynamical</span> synchronization/desynchronization has already constituted the basis for the design and development of systems for long-term (tens of minutes), on-line, prospective prediction of epileptic seizures. Also, the criterion for the changes in the time constants of the observed synchronization/desynchronization at seizure points has been used to show resetting of the epileptic brain in patients with temporal lobe epilepsy (TLE), a phenomenon that implicates a possible homeostatic role for the seizures themselves to restore normal brain activity. In this paper, we introduce a new criterion to measure this resetting that utilizes changes in the level of observed synchronization/desynchronization. We compare this criterion's sensitivity of resetting with the old one based on the time constants of the observed synchronization/desynchronization. Next, we test the robustness of the resetting phenomena in terms of the utilized measures of EEG <span class="hlt">dynamics</span> by a comparative study involving STLmax, a measure of phase (ϕmax) and a measure of energy (E) using both criteria (i.e. the level and time constants of the observed synchronization/desynchronization). The measures are estimated from intracranial electroencephalographic (iEEG) recordings with subdural and depth electrodes from two patients with focal temporal lobe epilepsy and a total of 43 seizures. Techniques from <span class="hlt">optimization</span> theory, in particular quadratic bivalent programming, are applied to <span class="hlt">optimize</span> the performance of the three measures in detecting preictal entrainment. It is shown that using either of the two resetting criteria, and for all three <span class="hlt">dynamical</span> measures, <span class="hlt">dynamical</span> resetting at seizures occurs with a significantly higher probability (α = 0.05) than resetting at randomly selected non-seizure points in days of EEG recordings per patient. It is also shown that <span class="hlt">dynamical</span> resetting at seizures using time constants of STLmax synchronization/desynchronization occurs with a higher probability than using the other synchronization measures, whereas <span class="hlt">dynamical</span> resetting at seizures using the level of synchronization/desynchronization criterion is detected with similar probability using any of the three measures of synchronization. These findings show the robustness of seizure resetting with respect to measures of EEG <span class="hlt">dynamics</span> and criteria of resetting utilized, and the critical role it might play in further elucidation of ictogenesis, as well as in the development of novel treatments for epilepsy. PMID:21709753</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007SPIE.6773E..0LZ','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007SPIE.6773E..0LZ"><span id="translatedtitle">Dependence topology <span class="hlt">optimization</span> in <span class="hlt">dynamic</span> peer-to-peer database network</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhao, Zhichao; Zhao, Zheng; Shi, Qingwei</p> <p>2007-09-01</p> <p>The scheme of <span class="hlt">dynamic</span> coordination rules in peer-to-peer database uses rule caching and forwarding to successfully solve the dependence tree break problem in the situation that peers can join and leave freely. But there are still problems that weaken the performance of query processing in this scheme. Coordination rules in cache are merged in run time when bypassing break points. If dependence trees can be <span class="hlt">optimized</span> into a form robust against peer absence beforehand, the query process will be more efficient. This paper proposes such mechanism by doing coordination rule combinations when new peer joins the dependence tree and new forwarded coordination rule arrives in cache. When some peers leave, queries take one existing bypass rule for reformulation, instead of concatenating cached ones from scratch. In effect, this mechanism <span class="hlt">optimizes</span> dependence tree into a more robust topology whenever new peer joins. Even when there is no peer absence, bypass rules can make query processing more efficient without following through many mediating peers, especially when data are updated frequently and frequent queries are needed. At the same time, the original dependence tree are maintained for data cache query when the target peer is absent. Since <span class="hlt">dynamic</span> coordination rules are expressed in XSLT, we try to find a way to form one XSLT whose function is equal to a chain of XSLTs, similar to the XML reasoning. The protocol also needs to be improved to inform to launch topology <span class="hlt">optimization</span> when new peer join or rule changes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JChPh.141l4110W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JChPh.141l4110W"><span id="translatedtitle">Fast <span class="hlt">optimization</span> of binary clusters using a novel <span class="hlt">dynamic</span> lattice searching method</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wu, Xia; Cheng, Wen</p> <p>2014-09-01</p> <p>Global <span class="hlt">optimization</span> of binary clusters has been a difficult task despite of much effort and many efficient methods. Directing toward two types of elements (i.e., homotop problem) in binary clusters, two classes of virtual <span class="hlt">dynamic</span> lattices are constructed and a modified <span class="hlt">dynamic</span> lattice searching (DLS) method, i.e., binary DLS (BDLS) method, is developed. However, it was found that the BDLS can only be utilized for the <span class="hlt">optimization</span> of binary clusters with small sizes because homotop problem is hard to be solved without atomic exchange operation. Therefore, the iterated local search (ILS) method is adopted to solve homotop problem and an efficient method based on the BDLS method and ILS, named as BDLS-ILS, is presented for global <span class="hlt">optimization</span> of binary clusters. In order to assess the efficiency of the proposed method, binary Lennard-Jones clusters with up to 100 atoms are investigated. Results show that the method is proved to be efficient. Furthermore, the BDLS-ILS method is also adopted to study the geometrical structures of (AuPd)79 clusters with DFT-fit parameters of Gupta potential.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22308894','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22308894"><span id="translatedtitle">Fast <span class="hlt">optimization</span> of binary clusters using a novel <span class="hlt">dynamic</span> lattice searching method</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wu, Xia Cheng, Wen</p> <p>2014-09-28</p> <p>Global <span class="hlt">optimization</span> of binary clusters has been a difficult task despite of much effort and many efficient methods. Directing toward two types of elements (i.e., homotop problem) in binary clusters, two classes of virtual <span class="hlt">dynamic</span> lattices are constructed and a modified <span class="hlt">dynamic</span> lattice searching (DLS) method, i.e., binary DLS (BDLS) method, is developed. However, it was found that the BDLS can only be utilized for the <span class="hlt">optimization</span> of binary clusters with small sizes because homotop problem is hard to be solved without atomic exchange operation. Therefore, the iterated local search (ILS) method is adopted to solve homotop problem and an efficient method based on the BDLS method and ILS, named as BDLS-ILS, is presented for global <span class="hlt">optimization</span> of binary clusters. In order to assess the efficiency of the proposed method, binary Lennard-Jones clusters with up to 100 atoms are investigated. Results show that the method is proved to be efficient. Furthermore, the BDLS-ILS method is also adopted to study the geometrical structures of (AuPd){sub 79} clusters with DFT-fit parameters of Gupta potential.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013CNSNS..18.2202P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013CNSNS..18.2202P"><span id="translatedtitle"><span class="hlt">Dynamics</span> of hepatitis C under <span class="hlt">optimal</span> therapy and sampling based analysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pachpute, Gaurav; Chakrabarty, Siddhartha P.</p> <p>2013-08-01</p> <p>We examine two models for hepatitis C viral (HCV) <span class="hlt">dynamics</span>, one for monotherapy with interferon (IFN) and the other for combination therapy with IFN and ribavirin. <span class="hlt">Optimal</span> therapy for both the models is determined using the steepest gradient method, by defining an objective functional which minimizes infected hepatocyte levels, virion population and side-effects of the drug(s). The <span class="hlt">optimal</span> therapies for both the models show an initial period of high efficacy, followed by a gradual decline. The period of high efficacy coincides with a significant decrease in the viral load, whereas the efficacy drops after hepatocyte levels are restored. We use the Latin hypercube sampling technique to randomly generate a large number of patient scenarios and study the <span class="hlt">dynamics</span> of each set under the <span class="hlt">optimal</span> therapy already determined. Results show an increase in the percentage of responders (indicated by drop in viral load below detection levels) in case of combination therapy (72%) as compared to monotherapy (57%). Statistical tests performed to study correlations between sample parameters and time required for the viral load to fall below detection level, show a strong monotonic correlation with the death rate of infected hepatocytes, identifying it to be an important factor in deciding individual drug regimens.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/10215175','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/10215175"><span id="translatedtitle">GLLS for <span class="hlt">optimally</span> sampled continuous <span class="hlt">dynamic</span> system modeling: theory and algorithm.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Feng, D; Ho, D; Lau, K K; Siu, W C</p> <p>1999-04-01</p> <p>The original generalized linear least squares (GLLS) algorithm was developed for non-uniformly sampled biomedical system parameter estimation using finely sampled instantaneous measurements (D. Feng, S.C. Huang, Z. Wang, D. Ho, An unbiased parametric imaging algorithm for non-uniformly sampled biomedical system parameter estimation, IEEE Trans. Med. Imag. 15 (1996) 512-518). This algorithm is particularly useful for image-wide generation of parametric images with positron emission tomography (PET), as it is computationally efficient and statistically reliable (D. Feng, D. Ho, Chen, K., L.C. Wu, J.K. Wang, R.S. Liu, S.H. Yeh, An evaluation of the algorithms for determining local cerebral metabolic rates of glucose using positron emission tomography <span class="hlt">dynamic</span> data, IEEE Trans. Med. Imag. 14 (1995) 697-710). However, when <span class="hlt">dynamic</span> PET image data are sampled according to the <span class="hlt">optimal</span> image sampling schedule (OISS) to reduce memory and storage space (X. Li, D. Feng, K. Chen, <span class="hlt">Optimal</span> image sampling schedule: A new effective way to reduce <span class="hlt">dynamic</span> image storage space and functional image processing time, IEEE Trans. Med. Imag. 15 (1996) 710-718), only a few temporal image frames are recorded (e.g. only four images are recorded for the four parameter fluoro-deoxy-glucose (FDG) model). These image frames are recorded in terms of accumulated radio-activity counts and as a result, the direct application of GLLS is not reliable as instantaneous measurement samples can no longer be approximated by averaging of accumulated measurements over the sampling intervals. In this paper, we extend GLLS to OISS-GLLS which deals with the fewer accumulated measurement samples obtained from OISS <span class="hlt">dynamic</span> systems. The theory and algorithm of this new technique are formulated and studied extensively. To investigate statistical reliability and computational efficiency of OISS-GLLS, a simulation study using <span class="hlt">dynamic</span> PET data was performed. OISS-GLLS using 4-measurement samples was compared to the non-linear least squares (NLS) method using 22-measurement samples, GLLS using 22-measurement samples and OISS-NLS using 4-measurement samples. Results demonstrated that OISS-GLLS was able to achieve parameter estimates of equivalent accuracy and reliability in comparison to NLS or GLLS using finely sampled measurements (22-measurement samples), or OISS-NLS using <span class="hlt">optimally</span> sampled measurements (4-measurement samples). Further more, as fewer measurement samples are used in OISS-GLLS, this algorithm is computationally faster than NLS or GLLS. Therefore, OISS-GLLS is well-suited for image-wide parameter estimation when PET image data are recorded according to the <span class="hlt">optimal</span> image sampling schedule. PMID:10215175</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140011926','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140011926"><span id="translatedtitle">Conceptual Design <span class="hlt">Optimization</span> of an Augmented Stability Aircraft Incorporating <span class="hlt">Dynamic</span> Response and Actuator Constraints</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Welstead, Jason; Crouse, Gilbert L., Jr.</p> <p>2014-01-01</p> <p>Empirical sizing guidelines such as tail volume coefficients have long been used in the early aircraft design phases for sizing stabilizers, resulting in conservatively stable aircraft. While successful, this results in increased empty weight, reduced performance, and greater procurement and operational cost relative to an aircraft with <span class="hlt">optimally</span> sized surfaces. Including flight <span class="hlt">dynamics</span> in the conceptual design process allows the design to move away from empirical methods while implementing modern control techniques. A challenge of flight <span class="hlt">dynamics</span> and control is the numerous design variables, which are changing fluidly throughout the conceptual design process, required to evaluate the system response to some disturbance. This research focuses on addressing that challenge not by implementing higher order tools, such as computational fluid <span class="hlt">dynamics</span>, but instead by linking the lower order tools typically used within the conceptual design process so each discipline feeds into the other. In thisresearch, flight <span class="hlt">dynamics</span> and control was incorporated into the conceptual design process along with the traditional disciplines of vehicle sizing, weight estimation, aerodynamics, and performance. For the controller, a linear quadratic regulator structure with constant gains has been specified to reduce the user input. Coupling all the disciplines in the conceptual design phase allows the aircraft designer to explore larger design spaces where stabilizers are sized according to <span class="hlt">dynamic</span> response constraints rather than historical static margin and volume coefficient guidelines.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/9735897','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/9735897"><span id="translatedtitle"><span class="hlt">Optimized</span> acquisition time and image sampling for <span class="hlt">dynamic</span> SPECT of Tl-201.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lau, C H; Eberl, S; Feng, D; Iida, H; Lun, P K; Siu, W C; Tamura, Y; Bautovich, G J; Ono, Y</p> <p>1998-06-01</p> <p>With the recent development in scatter and attenuation correction algorithms, <span class="hlt">dynamic</span> single photon emission computerized tomography (SPECT) can potentially yield physiological parameters, with tracers exhibiting suitable kinetics such as thallium-201 (Tl-201). A systematic way is proposed to investigate the minimum data acquisition times and sampling requirements for estimating physiological parameters with quantitative <span class="hlt">dynamic</span> SPECT. Two different sampling schemes were investigated with Monte Carlo simulations: 1) Continuous data collection for total study duration ranging from 30-240 min. 2) Continuous data collection for first 10-45 min followed by a delayed study at approximately 3 h. Tissue time activity curves with realistic noise were generated from a mean plasma time activity curve and rate constants (K1 - k4) derived from Tl-201 kinetic studies in 16 dogs. Full <span class="hlt">dynamic</span> sampling schedules (DynSS) were compared to optimum sampling schedules (OSS). We found that OSS can reliably estimate the blood flow related K1 and Vd comparable to DynSS. A 30-min continuous collection was sufficient if only K1 was of interest. A split session schedule of a 30-min <span class="hlt">dynamic</span> followed by a static study at 3 h allowed reliable estimation of both K1 and Vd avoiding the need for a prolonged (>60-min) continuous <span class="hlt">dynamic</span> acquisition. The methodology developed should also be applicable to <span class="hlt">optimizing</span> sampling schedules for other SPECT tracers. PMID:9735897</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMNG33A1575M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMNG33A1575M"><span id="translatedtitle">Empirical prediction of climate <span class="hlt">dynamics</span>: <span class="hlt">optimal</span> models, derived from time series</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mukhin, D.; Loskutov, E. M.; Gavrilov, A.; Feigin, A. M.</p> <p>2013-12-01</p> <p>The new empirical method for prediction of climate indices by the analysis of climatic fields' time series is suggested. The method is based on construction of prognostic models of evolution operator (EO) in low-dimensional subspaces of system's phase space. One of the main points of suggested analysis is reconstruction of appropriate basis of <span class="hlt">dynamical</span> variables (predictors) from spatially distributed data: different ways of data decomposition are discussed in the report including EOFs, MSSA and other relevant data rotations. We consider the models of different complexity for EO reconstruction, from linear statistical models of particular indices to more complex artificial neural network (ANN) models of climatic patterns <span class="hlt">dynamics</span>, which take the form of discrete random <span class="hlt">dynamical</span> systems [1]. Very important problem, that always arises in empirical modeling approaches, is <span class="hlt">optimal</span> model selection criterium: appropriate regularization procedure is needed to avoid overfitted model. Particulary, it includes finding the <span class="hlt">optimal</span> structural parameters of the model such as dimension of variables vector, i.e. number of principal components used for modeling, number of states used for prediction, and number of parameters determining quality of approximation. In this report the minimal descriptive length (MDL) approach [2] is proposed for this purpose: the model providing most data compression is chosen. Results of application of suggested method to analysis of SST and SLP fields' time series [3] covering last 30-50 years are presented: predictions of different climate indices time series including NINO 3.4, MEI, PDO, NOA are shown. References: 1. Y. I. Molkov, E. M. Loskutov, D. N. Mukhin, and A. M. Feigin, Random <span class="hlt">dynamical</span> models from time series, Phys. Rev. E 85, 036216, 2012 2. Molkov, Ya.I., D.N. Mukhin, E.M. Loskutov, A.M. Feigin, and G.A. Fidelin, Using the minimum description length principle for global reconstruction of <span class="hlt">dynamic</span> systems from noisy time series. Phys. Rev. E, 80, 046207, 2009 3. IRI/LDEO (http://iridl.ldeo.columbia.edu/)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3496753','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3496753"><span id="translatedtitle">Gold Nanoparticle Aggregation for Quantification of Oligonucleotides: <span class="hlt">Optimization</span> and Increased <span class="hlt">Dynamic</span> Range</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Cordray, Michael S.; Amdahl, Matthew; Richards-Kortum, Rebecca R.</p> <p>2012-01-01</p> <p>A variety of assays have been proposed to detect small quantities of nucleic acids at the point-of-care. One approach relies on target-induced aggregation of gold nanoparticles functionalized with oligonucleotide sequences complementary to adjacent regions on the targeted sequence. In the presence of the target sequence, the gold nanoparticles aggregate, producing an easily detectable shift in the optical scattering properties of the solution. The major limitations of this assay are that it requires heating, and that long incubation times are required to produce a result. This study aims to <span class="hlt">optimize</span> the assay conditions and optical readout, with the goals of eliminating the need for heating and reducing the time to result without sacrificing sensitivity or <span class="hlt">dynamic</span> range. By <span class="hlt">optimizing</span> assay conditions and measuring the spectrum of scattered light at the endpoint of incubation, we find that the assay is capable of producing quantifiable results at room temperature in 30 minutes with a linear <span class="hlt">dynamic</span> range spanning from 150 amoles to 15 fmoles of target. If changes in light scattering are measured <span class="hlt">dynamically</span> during the incubation process, the linear range can be expanded 2-fold, spanning 50 amoles to 500 fmoles, while decreasing the time to result down to 10 minutes. PMID:23000603</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23845276','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23845276"><span id="translatedtitle">Inference for <span class="hlt">optimal</span> <span class="hlt">dynamic</span> treatment regimes using an adaptive m-out-of-n bootstrap scheme.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chakraborty, Bibhas; Laber, Eric B; Zhao, Yingqi</p> <p>2013-09-01</p> <p>A <span class="hlt">dynamic</span> treatment regime consists of a set of decision rules that dictate how to individualize treatment to patients based on available treatment and covariate history. A common method for estimating an <span class="hlt">optimal</span> <span class="hlt">dynamic</span> treatment regime from data is Q-learning which involves nonsmooth operations of the data. This nonsmoothness causes standard asymptotic approaches for inference like the bootstrap or Taylor series arguments to breakdown if applied without correction. Here, we consider the m-out-of-n bootstrap for constructing confidence intervals for the parameters indexing the <span class="hlt">optimal</span> <span class="hlt">dynamic</span> regime. We propose an adaptive choice of m and show that it produces asymptotically correct confidence sets under fixed alternatives. Furthermore, the proposed method has the advantage of being conceptually and computationally much simple than competing methods possessing this same theoretical property. We provide an extensive simulation study to compare the proposed method with currently available inference procedures. The results suggest that the proposed method delivers nominal coverage while being less conservative than alternatives. The proposed methods are implemented in the qLearn R-package and have been made available on the Comprehensive R-Archive Network (http://cran.r-project.org/). Analysis of the Sequenced Treatment Alternatives to Relieve Depression (STAR*D) study is used as an illustrative example. PMID:23845276</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3141573','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3141573"><span id="translatedtitle">Design of <span class="hlt">Optimal</span> Treatments for Neuromusculoskeletal Disorders using Patient-Specific Multibody <span class="hlt">Dynamic</span> Models</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Fregly, Benjamin J.</p> <p>2011-01-01</p> <p>Disorders of the human neuromusculoskeletal system such as osteoarthritis, stroke, cerebral palsy, and paraplegia significantly affect mobility and result in a decreased quality of life. Surgical and rehabilitation treatment planning for these disorders is based primarily on static anatomic measurements and <span class="hlt">dynamic</span> functional measurements filtered through clinical experience. While this subjective treatment planning approach works well in many cases, it does not predict accurate functional outcome in many others. This paper presents a vision for how patient-specific multibody <span class="hlt">dynamic</span> models can serve as the foundation for an objective treatment planning approach that identifies <span class="hlt">optimal</span> treatments and treatment parameters on an individual patient basis. First, a computational paradigm is presented for constructing patient-specific multibody <span class="hlt">dynamic</span> models. This paradigm involves a combination of patient-specific skeletal models, muscle-tendon models, neural control models, and articular contact models, with the complexity of the complete model being dictated by the requirements of the clinical problem being addressed. Next, three clinical applications are presented to illustrate how such models could be used in the treatment design process. One application involves the design of patient-specific gait modification strategies for knee osteoarthritis rehabilitation, a second involves the selection of <span class="hlt">optimal</span> patient-specific surgical parameters for a particular knee osteoarthritis surgery, and the third involves the design of patient-specific muscle stimulation patterns for stroke rehabilitation. The paper concludes by discussing important challenges that need to be overcome to turn this vision into reality. PMID:21785529</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/18835500','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/18835500"><span id="translatedtitle">Accurate estimation of cardinal growth temperatures of Escherichia coli from <span class="hlt">optimal</span> <span class="hlt">dynamic</span> experiments.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Van Derlinden, E; Bernaerts, K; Van Impe, J F</p> <p>2008-11-30</p> <p>Prediction of the microbial growth rate as a response to changing temperatures is an important aspect in the control of food safety and food spoilage. Accurate model predictions of the microbial evolution ask for correct model structures and reliable parameter values with good statistical quality. Given the widely accepted validity of the Cardinal Temperature Model with Inflection (CTMI) [Rosso, L., Lobry, J. R., Bajard, S. and Flandrois, J. P., 1995. Convenient model to describe the combined effects of temperature and pH on microbial growth, Applied and Environmental Microbiology, 61: 610-616], this paper focuses on the accurate estimation of its four parameters (T(min), T(opt), T(max) and micro(opt)) by applying the technique of <span class="hlt">optimal</span> experiment design for parameter estimation (OED/PE). This secondary model describes the influence of temperature on the microbial specific growth rate from the minimum to the maximum temperature for growth. <span class="hlt">Dynamic</span> temperature profiles are <span class="hlt">optimized</span> within two temperature regions ([15 degrees C, 43 degrees C] and [15 degrees C, 45 degrees C]), focusing on the minimization of the parameter estimation (co)variance (D-<span class="hlt">optimal</span> design). The <span class="hlt">optimal</span> temperature profiles are implemented in a computer controlled bioreactor, and the CTMI parameters are identified from the resulting experimental data. Approximately equal CTMI parameter values were derived irrespective of the temperature region, except for T(max). The latter could only be estimated accurately from the <span class="hlt">optimal</span> experiments within [15 degrees C, 45 degrees C]. This observation underlines the importance of selecting the upper temperature constraint for OED/PE as close as possible to the true T(max). Cardinal temperature estimates resulting from designs within [15 degrees C, 45 degrees C] correspond with values found in literature, are characterized by a small uncertainty error and yield a good result during validation. As compared to estimates from non-<span class="hlt">optimized</span> <span class="hlt">dynamic</span> experiments, more reliable CTMI parameter values were obtained from the <span class="hlt">optimal</span> experiments within [15 degrees C, 45 degrees C]. PMID:18835500</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007JCoAM.203..345S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007JCoAM.203..345S"><span id="translatedtitle">On PDE solution in transient <span class="hlt">optimization</span> of gas networks</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Steinbach, Marc C.</p> <p>2007-06-01</p> <p>Operative planning in gas distribution networks leads to large-scale <span class="hlt">mixed-integer</span> <span class="hlt">optimization</span> problems involving a hyperbolic PDE defined on a graph. We consider the NLP obtained under prescribed combinatorial decisions--or as relaxation in a branch-and-bound framework, addressing in particular the KKT systems arising in primal-dual interior methods. We propose a custom solution algorithm using sparse projections locally in time, based on the KKT systems' structural properties in space as induced by the discretized gas flow equations in combination with the underlying network topology. The numerical efficiency and accuracy of the algorithm are investigated, and detailed computational comparisons with a previously developed control space method and with the multifrontal solver MA27 are provided.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012PMB....57N.173E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012PMB....57N.173E"><span id="translatedtitle">Optical tracking of contrast medium bolus to <span class="hlt">optimize</span> bolus shape and timing in <span class="hlt">dynamic</span> computed tomography</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Eisa, Fabian; Brauweiler, Robert; Peetz, Alexander; Hupfer, Martin; Nowak, Tristan; Kalender, Willi A.</p> <p>2012-05-01</p> <p>One of the biggest challenges in <span class="hlt">dynamic</span> contrast-enhanced CT is the <span class="hlt">optimal</span> synchronization of scan start and duration with contrast medium administration in order to <span class="hlt">optimize</span> image contrast and to reduce the amount of contrast medium. We present a new optically based approach, which was developed to investigate and <span class="hlt">optimize</span> bolus timing and shape. The time-concentration curve of an intravenously injected test bolus of a dye is measured in peripheral vessels with an optical sensor prior to the diagnostic CT scan. The curves can be used to assess bolus shapes as a function of injection protocols and to determine contrast medium arrival times. Preliminary results for phantom and animal experiments showed the expected linear behavior between dye concentration and absorption. The kinetics of the dye was compared to iodinated contrast medium and was found to be in good agreement. The contrast enhancement curves were reliably detected in three mice with individual bolus shapes and delay times of 2.1, 3.5 and 6.1 s, respectively. The optical sensor appears to be a promising approach to <span class="hlt">optimize</span> injection protocols and contrast enhancement timing and is applicable to all modalities without implying any additional radiation dose. Clinical tests are still necessary.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22463713','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22463713"><span id="translatedtitle">Modeling forest stand <span class="hlt">dynamics</span> from <span class="hlt">optimal</span> balances of carbon and nitrogen.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Valentine, Harry T; Mkel, Annikki</p> <p>2012-06-01</p> <p>We formulate a <span class="hlt">dynamic</span> evolutionary <span class="hlt">optimization</span> problem to predict the <span class="hlt">optimal</span> pattern by which carbon (C) and nitrogen (N) are co-allocated to fine-root, leaf, and wood production, with the objective of maximizing height growth rate, year by year, in an even-aged stand. Height growth is maximized with respect to two adaptive traits, leaf N concentration and the ratio of fine-root mass to sapwood cross-sectional area. Constraints on the <span class="hlt">optimization</span> include pipe-model structure, the C cost of N acquisition, and agreement between the C and N balances. The latter is determined by two models of height growth rate, one derived from the C balance and the other from the N balance; agreement is defined by identical growth rates. Predicted time-courses of maximized height growth rate accord with general observations. Across an N gradient, higher N availability leads to greater N utilization and net primary productivity, larger trees, and greater stocks of leaf and live wood biomass, with declining gains as a result of saturation effects at high N availability. Fine-root biomass is greatest at intermediate N availability. Predicted leaf and fine-root stocks agree with data from coniferous stands across Finland. <span class="hlt">Optimal</span> C-allocation patterns agree with published observations and model analyses. PMID:22463713</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24374404','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24374404"><span id="translatedtitle">A model of bi-mode transmission <span class="hlt">dynamics</span> of hepatitis C with <span class="hlt">optimal</span> control.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Imran, Mudassar; Rafique, Hassan; Khan, Adnan; Malik, Tufail</p> <p>2014-06-01</p> <p>In this paper, we present a rigorous mathematical analysis of a deterministic model for the transmission <span class="hlt">dynamics</span> of hepatitis C. The model is suitable for populations where two frequent modes of transmission of hepatitis C virus, namely unsafe blood transfusions and intravenous drug use, are dominant. The susceptible population is divided into two distinct compartments, the intravenous drug users and individuals undergoing unsafe blood transfusions. Individuals belonging to each compartment may develop acute and then possibly chronic infections. Chronically infected individuals may be quarantined. The analysis indicates that the eradication and persistence of the disease is completely determined by the magnitude of basic reproduction number R(c). It is shown that for the basic reproduction number R(c) < 1, the disease-free equilibrium is locally and globally asymptotically stable. For R(c) > 1, an endemic equilibrium exists and the disease is uniformly persistent. In addition, we present the uncertainty and sensitivity analyses to investigate the influence of different important model parameters on the disease prevalence. When the infected population persists, we have designed a time-dependent <span class="hlt">optimal</span> quarantine strategy to minimize it. The Pontryagin's Maximum Principle is used to characterize the <span class="hlt">optimal</span> control in terms of an <span class="hlt">optimality</span> system which is solved numerically. Numerical results for the <span class="hlt">optimal</span> control are compared against the constant controls and their efficiency is discussed. PMID:24374404</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004IJTPE.124..690F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004IJTPE.124..690F"><span id="translatedtitle">Comparative Studies of Particle Swarm <span class="hlt">Optimization</span> Techniques for Reactive Power Allocation Planning in Power Systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fukuyama, Yoshikazu</p> <p></p> <p>This paper compares particle swarm <span class="hlt">optimization</span> (PSO) techniques for a reactive power allocation planning problem in power systems. The problem can be formulated as a <span class="hlt">mixed-integer</span> nonlinear <span class="hlt">optimization</span> problem (MINLP). The PSO based methods determines a reactive power allocation strategy with continuous and discrete state variables such as automatic voltage regulator (AVR) operating values of electric power generators, tap positions of on-load tap changer (OLTC) of transformers, and the number of reactive power compensation equipment. Namely, this paper investigates applicability of PSO techniques to one of the practical MINLPs in power systems. Four variations of PSO: PSO with inertia weight approach (IWA), PSO with constriction factor approach (CFA), hybrid particle swarm <span class="hlt">optimization</span> (HPSO) with IWA, and HPSO with CFA are compared. The four methods are applied to the standard IEEE14 bus system and a practical 112 bus system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004IJTIA.124..366S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004IJTIA.124..366S"><span id="translatedtitle">The Automatic Formulating Method of the <span class="hlt">Optimal</span> Operating Planning Problem for Energy Supply Systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Suzuki, Naohiko; Ueda, Takaharu; Sasakawa, Koichi</p> <p></p> <p>The problem of the <span class="hlt">optimal</span> operating planning for energy supply system is formulated as <span class="hlt">mixed-integer</span> linear programming (MILP), but, it is too complicated for most untrained operators with little experience to apply the method. This paper proposes an automatic evaluating method of the <span class="hlt">optimal</span> operating planning for energy supply system in using simple data. The problem can be formulated only from characteristics of equipment, tariff of input energy, and energy demands. The connection of equipment is defined as a matrix, and generated from property data of equipment. The constraints and objective function of the problem are generated from relation-ship data in the matrix and characteristics of equipment. An <span class="hlt">optimization</span> calculation for the problem is automatically carried out. It is confirmed that any operator can evaluate many alternative configurations of the energy supply systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1988WRR....24..541G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1988WRR....24..541G"><span id="translatedtitle"><span class="hlt">Optimal</span> dewatering schemes in the foundation design of an electronuclear plant</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Galeati, Giorgio; Gambolati, Giuseppe</p> <p>1988-04-01</p> <p>A three-dimensional finite element model combined with an <span class="hlt">optimization</span> approach based on linear <span class="hlt">mixed</span> <span class="hlt">integer</span> programming is developed and applied to assist in the design of the dewatering system for the electronuclear plant to be built by the Italian Electric Agency (ENEL) in Trino Vercellese, northwestern Italy. The foundations site is encompassed by a 25- to 35-m deep plastic wall with the purpose of protecting the unconfined aquifer from the significant water table lowering required by the construction project. To reduce further the propagation of the depression cone a large amount of the water pumped out is reinjected through "ad hoc" recharge ditches. The finite element <span class="hlt">optimization</span> model includes both the natural and the artificial constraints and provides several <span class="hlt">optimal</span> withdrawal strategies for the dewatering system design concerning the distribution of the abstraction wells and the corresponding pumping rates. Physical and economical objective functions are explored and the related solutions are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhRvA..93d2339B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhRvA..93d2339B"><span id="translatedtitle">Steering quantum <span class="hlt">dynamics</span> via bang-bang control: Implementing <span class="hlt">optimal</span> fixed-point quantum search algorithm</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bhole, Gaurav; Anjusha, V. S.; Mahesh, T. S.</p> <p>2016-04-01</p> <p>A robust control over quantum <span class="hlt">dynamics</span> is of paramount importance for quantum technologies. Many of the existing control techniques are based on smooth Hamiltonian modulations involving repeated calculations of basic unitaries resulting in time complexities scaling rapidly with the length of the control sequence. Here we show that bang-bang controls need one-time calculation of basic unitaries and hence scale much more efficiently. By employing a global <span class="hlt">optimization</span> routine such as the genetic algorithm, it is possible to synthesize not only highly intricate unitaries, but also certain nonunitary operations. We demonstrate the unitary control through the implementation of the <span class="hlt">optimal</span> fixed-point quantum search algorithm in a three-qubit nuclear magnetic resonance (NMR) system. Moreover, by combining the bang-bang pulses with the crusher gradients, we also demonstrate nonunitary transformations of thermal equilibrium states into effective pure states in three- as well as five-qubit NMR systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22410419','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22410419"><span id="translatedtitle">Coherent control of plasma <span class="hlt">dynamics</span> by feedback-<span class="hlt">optimized</span> wavefront manipulation</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>He, Z.-H.; Hou, B.; Gao, G.; Nees, J. A.; Krushelnick, K.; Thomas, A. G. R.; Lebailly, V.; Clarke, R.</p> <p>2015-05-15</p> <p>Plasmas generated by an intense laser pulse can support coherent structures such as large amplitude wakefield that can affect the outcome of an experiment. We investigate the coherent control of plasma <span class="hlt">dynamics</span> by feedback-<span class="hlt">optimized</span> wavefront manipulation using a deformable mirror. The experimental outcome is directly used as feedback in an evolutionary algorithm for <span class="hlt">optimization</span> of the phase front of the driving laser pulse. In this paper, we applied this method to two different experiments: (i) acceleration of electrons in laser driven plasma waves and (ii) self-compression of optical pulses induced by ionization nonlinearity. The manipulation of the laser wavefront leads to orders of magnitude improvement to electron beam properties such as the peak charge, beam divergence, and transverse emittance. The demonstration of coherent control for plasmas opens new possibilities for future laser-based accelerators and their applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20150005628&hterms=chemistry&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dchemistry','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20150005628&hterms=chemistry&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dchemistry"><span id="translatedtitle">Partial Overhaul and Initial Parallel <span class="hlt">Optimization</span> of KINETICS, a Coupled <span class="hlt">Dynamics</span> and Chemistry Atmosphere Model</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nguyen, Howard; Willacy, Karen; Allen, Mark</p> <p>2012-01-01</p> <p>KINETICS is a coupled <span class="hlt">dynamics</span> and chemistry atmosphere model that is data intensive and computationally demanding. The potential performance gain from using a supercomputer motivates the adaptation from a serial version to a parallelized one. Although the initial parallelization had been done, bottlenecks caused by an abundance of communication calls between processors led to an unfavorable drop in performance. Before starting on the parallel <span class="hlt">optimization</span> process, a partial overhaul was required because a large emphasis was placed on streamlining the code for user convenience and revising the program to accommodate the new supercomputers at Caltech and JPL. After the first round of <span class="hlt">optimizations</span>, the partial runtime was reduced by a factor of 23; however, performance gains are dependent on the size of the data, the number of processors requested, and the computer used.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25635665','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25635665"><span id="translatedtitle">Fluid <span class="hlt">dynamic</span> analysis of a continuous stirred tank reactor for technical <span class="hlt">optimization</span> of wastewater digestion.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hurtado, F J; Kaiser, A S; Zamora, B</p> <p>2015-03-15</p> <p>Continuous stirred tank reactors (CSTR) are widely used in wastewater treatment plants to reduce the organic matter and microorganism present in sludge by anaerobic digestion. The present study carries out a numerical analysis of the fluid <span class="hlt">dynamic</span> behaviour of a CSTR in order to <span class="hlt">optimize</span> the process energetically. The characterization of the sludge flow inside the digester tank, the residence time distribution and the active volume of the reactor under different criteria are determined. The effects of design and power of the mixing system on the active volume of the CSTR are analyzed. The numerical model is solved under non-steady conditions by examining the evolution of the flow during the stop and restart of the mixing system. An intermittent regime of the mixing system, which kept the active volume between 94% and 99%, is achieved. The results obtained can lead to the eventual energy <span class="hlt">optimization</span> of the mixing system of the CSTR. PMID:25635665</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20100031269&hterms=Earth+moon&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DEarth%2Bmoon','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20100031269&hterms=Earth+moon&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DEarth%2Bmoon"><span id="translatedtitle"><span class="hlt">Dynamic</span> <span class="hlt">Optimization</span> of Multi-Spacecraft Relative Navigation Configurations in the Earth-Moon System</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Villac, Benjamin; Chow, Channing; Lo, Martin; Hintz, Gerald; Nazari, Zahra</p> <p>2010-01-01</p> <p>In this paper, the notion of relative navigation introduced by Hill, Lo and Born is analyzed for a large class of periodic orbits in the Earth-Moon three-body problem, due to its potential in supporting Moon exploration efforts. In particular, a navigation metric is introduced and used as a cost function to <span class="hlt">optimize</span> over a class of periodic orbits. While the problem could be solve locally as an <span class="hlt">optimal</span> control problem, a <span class="hlt">dynamical</span> based approach that allows for a global/systematic view of the problem is proposed. First, the simpler problem of multiple spacecraft placement on a given periodic orbit is solved before the notion of continuation and bifurcation analysis is used to expand the range of solutions thus obtained.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21528600','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21528600"><span id="translatedtitle"><span class="hlt">Optimal</span> <span class="hlt">dynamics</span> for quantum-state and entanglement transfer through homogeneous quantum systems</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Banchi, L.; Apollaro, T. J. G.; Cuccoli, A.; Vaia, R.; Verrucchi, P.</p> <p>2010-11-15</p> <p>The capability of faithfully transmit quantum states and entanglement through quantum channels is one of the key requirements for the development of quantum devices. Different solutions have been proposed to accomplish such a challenging task, which, however, require either an ad hoc engineering of the internal interactions of the physical system acting as the channel or specific initialization procedures. Here we show that <span class="hlt">optimal</span> <span class="hlt">dynamics</span> for efficient quantum-state and entanglement transfer can be attained in generic quantum systems with homogeneous interactions by tuning the coupling between the system and the two attached qubits. We devise a general procedure to determine the <span class="hlt">optimal</span> coupling, and we explicitly implement it in the case of a channel consisting of a spin-(1/2)XY chain. The quality of quantum-state and entanglement transfer is found to be very good and, remarkably, almost independent of the channel length.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005WRR....41.5006R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005WRR....41.5006R"><span id="translatedtitle">Seawater intrusion policy analysis with a numerical spatially heterogeneous <span class="hlt">dynamic</span> <span class="hlt">optimization</span> model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Reinelt, Peter</p> <p>2005-05-01</p> <p>For more than 50 years, Monterey County and California State officials have pursued without success water policies to halt groundwater overdraft and seawater intrusion in the multilayer confined aquifers underlying arguably the most productive farmland in the United States. This study develops a general <span class="hlt">dynamic</span> <span class="hlt">optimization</span> model that emphasizes the institutional and physical characteristics that differentiate this policy problem from other groundwater extraction problems. The solution of the model exhibits heterogeneous spatial distribution of <span class="hlt">optimal</span> extraction based on spatially distributed extraction cost, pumping cost externality, and seawater intrusion stock externality. Comparison of model results under alternative management regimes elucidates landowner economic incentives, reveals the potential welfare loss of current state policy, and explains much of the history of the political economy of water in Monterey County.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JIEIB..94...43N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JIEIB..94...43N"><span id="translatedtitle">A <span class="hlt">Dynamic</span> Programming Algorithm for <span class="hlt">Optimal</span> Design of Tidal Power Plants</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nag, B.</p> <p>2013-03-01</p> <p>A <span class="hlt">dynamic</span> programming algorithm is proposed and demonstrated on a test case to determine the optimum operating schedule of a barrage tidal power plant to maximize the energy generation over a tidal cycle. Since consecutive sets of high and low tides can be predicted accurately for any tidal power plant site, this algorithm can be used to calculate the annual energy generation for different technical configurations of the plant. Thus an <span class="hlt">optimal</span> choice of a tidal power plant design can be made from amongst different design configurations yielding the least cost of energy generation. Since this algorithm determines the <span class="hlt">optimal</span> time of operation of sluice gate opening and turbine gates opening to maximize energy generation over a tidal cycle, it can also be used to obtain the annual schedule of operation of a tidal power plant and the minute-to-minute energy generation, for dissemination amongst power distribution utilities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhRvE..93d2212Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhRvE..93d2212Y"><span id="translatedtitle">Cluster statistics and quasisoliton <span class="hlt">dynamics</span> in microscopic <span class="hlt">optimal</span>-velocity models</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Bo; Xu, Xihua; Pang, John Z. F.; Monterola, Christopher</p> <p>2016-04-01</p> <p>Using the non-linear <span class="hlt">optimal</span> velocity models as an example, we show that there exists an emergent intrinsic scale that characterizes the interaction strength between multiple clusters appearing in the solutions of such models. The interaction characterizes the <span class="hlt">dynamics</span> of the localized quasisoliton structures given by the time derivative of the headways, and the intrinsic scale is analogous to the "charge" of the quasisolitons, leading to non-trivial cluster statistics from the random perturbations to the initial steady states of uniform headways. The cluster statistics depend both on the quasisoliton charge and the density of the traffic. The intrinsic scale is also related to an emergent quantity that gives the extremum headways in the cluster formation, as well as the coexistence curve separating the absolute stable phase from the metastable phase. The relationship is qualitatively universal for general <span class="hlt">optimal</span> velocity models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhRvE..92f0102R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhRvE..92f0102R"><span id="translatedtitle"><span class="hlt">Optimal</span> control in nonequilibrium systems: <span class="hlt">Dynamic</span> Riemannian geometry of the Ising model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rotskoff, Grant M.; Crooks, Gavin E.</p> <p>2015-12-01</p> <p>A general understanding of <span class="hlt">optimal</span> control in nonequilibrium systems would illuminate the operational principles of biological and artificial nanoscale machines. Recent work has shown that a system driven out of equilibrium by a linear response protocol is endowed with a Riemannian metric related to generalized susceptibilities, and that geodesics on this manifold are the nonequilibrium control protocols with the lowest achievable dissipation. While this elegant mathematical framework has inspired numerous studies of exactly solvable systems, no description of the thermodynamic geometry yet exists when the metric cannot be derived analytically. Herein, we numerically construct the <span class="hlt">dynamic</span> metric of the two-dimensional Ising model in order to study <span class="hlt">optimal</span> protocols for reversing the net magnetization.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25465790','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25465790"><span id="translatedtitle">Hydraulic <span class="hlt">optimization</span> of membrane bioreactor via baffle modification using computational fluid <span class="hlt">dynamics</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yan, Xiaoxu; Xiao, Kang; Liang, Shuai; Lei, Ting; Liang, Peng; Xue, Tao; Yu, Kaichang; Guan, Jing; Huang, Xia</p> <p>2014-11-01</p> <p>Baffles are a key component of an airlift membrane bioreactor (MBR), which could enhance membrane surface shear for fouling control. In order to obtain an <span class="hlt">optimal</span> hydraulic condition of the reactor, the effects of baffle location and size were systematically explored in this study. Computational fluid <span class="hlt">dynamics</span> (CFD) was used to investigate the hydrodynamics in a bench-scale airlift flat sheet MBR with various baffle locations and sizes. Validated simulation results showed that side baffles were more effective in elevating membrane surface shear than front baffles. The maximum average shear stress was achieved by adjusting baffle size when both front and side baffles were installed. With the <span class="hlt">optimized</span> baffle configuration, the shear stress was 10-30% higher than that without baffles at a same aeration intensity (specific air demand per membrane area in the range of 0-0.45m(3)m(-2)h(-1)). The effectiveness of baffles was particularly prominent at lower aeration intensities. PMID:25465790</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhPl...22e6704H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhPl...22e6704H"><span id="translatedtitle">Coherent control of plasma <span class="hlt">dynamics</span> by feedback-<span class="hlt">optimized</span> wavefront manipulationa)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>He, Z.-H.; Hou, B.; Gao, G.; Lebailly, V.; Nees, J. A.; Clarke, R.; Krushelnick, K.; Thomas, A. G. R.</p> <p>2015-05-01</p> <p>Plasmas generated by an intense laser pulse can support coherent structures such as large amplitude wakefield that can affect the outcome of an experiment. We investigate the coherent control of plasma <span class="hlt">dynamics</span> by feedback-<span class="hlt">optimized</span> wavefront manipulation using a deformable mirror. The experimental outcome is directly used as feedback in an evolutionary algorithm for <span class="hlt">optimization</span> of the phase front of the driving laser pulse. In this paper, we applied this method to two different experiments: (i) acceleration of electrons in laser driven plasma waves and (ii) self-compression of optical pulses induced by ionization nonlinearity. The manipulation of the laser wavefront leads to orders of magnitude improvement to electron beam properties such as the peak charge, beam divergence, and transverse emittance. The demonstration of coherent control for plasmas opens new possibilities for future laser-based accelerators and their applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/13828','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/13828"><span id="translatedtitle"><span class="hlt">Optimization</span> of Fluid Front <span class="hlt">Dynamics</span> in Porous Media Using Rate Control: I. Equal Mobility Fluids</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sundaryanto, Bagus; Yortsos, Yanis C.</p> <p>1999-10-18</p> <p>In applications involving this injection of a fluid in a porous medium to displace another fluid, a main objective is the maximization of the displacement efficiency. For a fixed arrangement of injection and production points (sources and sinks), such <span class="hlt">optimization</span> is possible by controlling the injection rate policy. Despite its practical relevance, however, this aspect has received scant attention in the literature. In this paper, a fundamental approach based on <span class="hlt">optimal</span> control theory, for the case when the fluids are miscible, of equal viscosity and in the absence of dispersion and gravity effects. Both homogeneous and heterogeneous porous media are considered. From a fluid <span class="hlt">dynamics</span> viewpoint, this is a problem in the deformation of material lines in porous media, as a function of time-varying injection rates.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22098427','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22098427"><span id="translatedtitle"><span class="hlt">Optimizing</span> the <span class="hlt">dynamic</span> range extension of a radiochromic film dosimetry system</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Devic, Slobodan; Tomic, Nada; Soares, Christopher G.; Podgorsak, Ervin B.</p> <p>2009-02-15</p> <p>The authors present a radiochromic film dosimetry protocol for a multicolor channel radiochromic film dosimetry system consisting of the external beam therapy (EBT) model GAFCHROMIC film and the Epson Expression 1680 flat-bed document scanner. Instead of extracting only the red color channel, the authors are using all three color channels in the absorption spectrum of the EBT film to extend the <span class="hlt">dynamic</span> dose range of the radiochromic film dosimetry system. By <span class="hlt">optimizing</span> the dose range for each color channel, they obtained a system that has both precision and accuracy below 1.5%, and the <span class="hlt">optimized</span> ranges are 0-4 Gy for the red channel, 4-50 Gy for the green channel, and above 50 Gy for the blue channel.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25216191','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25216191"><span id="translatedtitle">Stochastic <span class="hlt">optimal</span> foraging: tuning intensive and extensive <span class="hlt">dynamics</span> in random searches.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bartumeus, Frederic; Raposo, Ernesto P; Viswanathan, Gandhimohan M; da Luz, Marcos G E</p> <p>2014-01-01</p> <p>Recent theoretical developments had laid down the proper mathematical means to understand how the structural complexity of search patterns may improve foraging efficiency. Under information-deprived scenarios and specific landscape configurations, Lévy walks and flights are known to lead to high search efficiencies. Based on a one-dimensional comparative analysis we show a mechanism by which, at random, a searcher can <span class="hlt">optimize</span> the encounter with close and distant targets. The mechanism consists of combining an <span class="hlt">optimal</span> diffusivity (<span class="hlt">optimally</span> enhanced diffusion) with a minimal diffusion constant. In such a way the search <span class="hlt">dynamics</span> adequately balances the tension between finding close and distant targets, while, at the same time, shifts the <span class="hlt">optimal</span> balance towards relatively larger close-to-distant target encounter ratios. We find that introducing a multiscale set of reorientations ensures both a thorough local space exploration without oversampling and a fast spreading <span class="hlt">dynamics</span> at the large scale. Lévy reorientation patterns account for these properties but other reorientation strategies providing similar statistical signatures can mimic or achieve comparable efficiencies. Hence, the present work unveils general mechanisms underlying efficient random search, beyond the Lévy model. Our results suggest that animals could tune key statistical movement properties (e.g. enhanced diffusivity, minimal diffusion constant) to cope with the very general problem of balancing out intensive and extensive random searching. We believe that theoretical developments to mechanistically understand stochastic search strategies, such as the one here proposed, are crucial to develop an empirically verifiable and comprehensive animal foraging theory. PMID:25216191</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4162546','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4162546"><span id="translatedtitle">Stochastic <span class="hlt">Optimal</span> Foraging: Tuning Intensive and Extensive <span class="hlt">Dynamics</span> in Random Searches</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Bartumeus, Frederic; Raposo, Ernesto P.; Viswanathan, Gandhimohan M.; da Luz, Marcos G. E.</p> <p>2014-01-01</p> <p>Recent theoretical developments had laid down the proper mathematical means to understand how the structural complexity of search patterns may improve foraging efficiency. Under information-deprived scenarios and specific landscape configurations, Lévy walks and flights are known to lead to high search efficiencies. Based on a one-dimensional comparative analysis we show a mechanism by which, at random, a searcher can <span class="hlt">optimize</span> the encounter with close and distant targets. The mechanism consists of combining an <span class="hlt">optimal</span> diffusivity (<span class="hlt">optimally</span> enhanced diffusion) with a minimal diffusion constant. In such a way the search <span class="hlt">dynamics</span> adequately balances the tension between finding close and distant targets, while, at the same time, shifts the <span class="hlt">optimal</span> balance towards relatively larger close-to-distant target encounter ratios. We find that introducing a multiscale set of reorientations ensures both a thorough local space exploration without oversampling and a fast spreading <span class="hlt">dynamics</span> at the large scale. Lévy reorientation patterns account for these properties but other reorientation strategies providing similar statistical signatures can mimic or achieve comparable efficiencies. Hence, the present work unveils general mechanisms underlying efficient random search, beyond the Lévy model. Our results suggest that animals could tune key statistical movement properties (e.g. enhanced diffusivity, minimal diffusion constant) to cope with the very general problem of balancing out intensive and extensive random searching. We believe that theoretical developments to mechanistically understand stochastic search strategies, such as the one here proposed, are crucial to develop an empirically verifiable and comprehensive animal foraging theory. PMID:25216191</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6892637','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6892637"><span id="translatedtitle"><span class="hlt">Dynamic</span> <span class="hlt">optimization</span> model of energy related economic planning and development for the Navajo nation</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Beladi, S.A.</p> <p>1983-01-01</p> <p>The Navajo reservation located in portions of Arizona, New Mexico and Utah is rich in low sulfur coal deposits, ideal for strip mining operation. The Navajo Nation has been leasing the mineral resources to non-Indian enterprises for purposes of extraction. Since the early 1950s the Navajo Nation has entered into extensive coal leases with several large companies and utilities. Contracts have committed huge quantities of Navajo coal for mining. This research was directed to evaluate the shadow prices of Navajo coal and identify <span class="hlt">optimal</span> coal extraction. An economic model of coal resource extraction over time was structured within an <span class="hlt">optimal</span> control theory framework. The control problem was formulated as a discrete <span class="hlt">dynamic</span> <span class="hlt">optimization</span> problem. A comparison of the shadow prices of coal deposits derived from the <span class="hlt">dynamic</span> model with the royalty payments the tribe receives on the basis of the present long-term lease contracts indicates that, in most cases, the tribe is paid considerably less than the amount of royalty projected by the model. Part of these discrepancies may be explained in terms of the low coal demand condition at the time of leasing and due to greater uncertainties with respect to the geologic information and other risks associated with mining operations. However, changes in the demand for coal with rigidly fixed terms of royalty rates will lead to non-<span class="hlt">optimal</span> extraction of coal. A corrective tax scheme is suggested on the basis of the results of this research. The proposed tax per unit of coal shipped from a site is the difference between the shadow price and the present royalty rate. The estimated tax rates over time are derived.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ChJME..29..124C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ChJME..29..124C"><span id="translatedtitle"><span class="hlt">Dynamic</span> topology multi force particle swarm <span class="hlt">optimization</span> algorithm and its application</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, Dongning; Zhang, Ruixing; Yao, Chengyu; Zhao, Zheyu</p> <p>2016-01-01</p> <p>Particle swarm <span class="hlt">optimization</span> (PSO) algorithm is an effective bio-inspired algorithm but it has shortage of premature convergence. Researchers have made some improvements especially in force rules and population topologies. However, the current algorithms only consider a single kind of force rules and lack consideration of comprehensive improvement in both multi force rules and population topologies. In this paper, a <span class="hlt">dynamic</span> topology multi force particle swarm <span class="hlt">optimization</span> (DTMFPSO) algorithm is proposed in order to get better search performance. First of all, the principle of the presented multi force particle swarm <span class="hlt">optimization</span> (MFPSO) algorithm is that different force rules are used in different search stages, which can balance the ability of global and local search. Secondly, a fitness-driven edge-changing (FE) topology based on the probability selection mechanism of roulette method is designed to cut and add edges between the particles, and the DTMFPSO algorithm is proposed by combining the FE topology with the MFPSO algorithm through concurrent evolution of both algorithm and structure in order to further improve the search accuracy. Thirdly, Benchmark functions are employed to evaluate the performance of the DTMFPSO algorithm, and test results show that the proposed algorithm is better than the well-known PSO algorithms, such as µPSO, MPSO, and EPSO algorithms. Finally, the proposed algorithm is applied to <span class="hlt">optimize</span> the process parameters for ultrasonic vibration cutting on SiC wafer, and the surface quality of the SiC wafer is improved by 12.8% compared with the PSO algorithm in Ref. [25]. This research proposes a DTMFPSO algorithm with multi force rules and <span class="hlt">dynamic</span> population topologies evolved simultaneously, and it has better search performance.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26043376','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26043376"><span id="translatedtitle">Process simulation and <span class="hlt">dynamic</span> control for marine oily wastewater treatment using UV irradiation.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jing, Liang; Chen, Bing; Zhang, Baiyu; Li, Pu</p> <p>2015-09-15</p> <p>UV irradiation and advanced oxidation processes have been recently regarded as promising solutions in removing polycyclic aromatic hydrocarbons (PAHs) from marine oily wastewater. However, such treatment methods are generally not sufficiently understood in terms of reaction mechanisms, process simulation and process control. These deficiencies can drastically hinder their application in shipping and offshore petroleum industries which produce bilge/ballast water and produced water as the main streams of marine oily wastewater. In this study, the factorial design of experiment was carried out to investigate the degradation mechanism of a typical PAH, namely naphthalene, under UV irradiation in seawater. Based on the experimental results, a three-layer feed-forward artificial neural network simulation model was developed to simulate the treatment process and to forecast the removal performance. A simulation-based <span class="hlt">dynamic</span> <span class="hlt">mixed</span> <span class="hlt">integer</span> nonlinear programming (SDMINP) approach was then proposed to intelligently control the treatment process by integrating the developed simulation model, genetic algorithm and multi-stage programming. The applicability and effectiveness of the developed approach were further tested though a case study. The experimental results showed that the influences of fluence rate and temperature on the removal of naphthalene were greater than those of salinity and initial concentration. The developed simulation model could well predict the UV-induced removal process under varying conditions. The case study suggested that the SDMINP approach, with the aid of the multi-stage control strategy, was able to significantly reduce treatment cost when comparing to the traditional single-stage process <span class="hlt">optimization</span>. The developed approach and its concept/framework have high potential of applicability in other environmental fields where a treatment process is involved and experimentation and modeling are used for process simulation and control. PMID:26043376</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.4050D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.4050D"><span id="translatedtitle"><span class="hlt">Optimizing</span> conjunctive use of surface water and groundwater resources with stochastic <span class="hlt">dynamic</span> programming</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Davidsen, Claus; Liu, Suxia; Mo, Xingguo; Rosbjerg, Dan; Bauer-Gottwein, Peter</p> <p>2014-05-01</p> <p><span class="hlt">Optimal</span> management of conjunctive use of surface water and groundwater has been attempted with different algorithms in the literature. In this study, a hydro-economic modelling approach to <span class="hlt">optimize</span> conjunctive use of scarce surface water and groundwater resources under uncertainty is presented. A stochastic <span class="hlt">dynamic</span> programming (SDP) approach is used to minimize the basin-wide total costs arising from water allocations and water curtailments. <span class="hlt">Dynamic</span> allocation problems with inclusion of groundwater resources proved to be more complex to solve with SDP than pure surface water allocation problems due to head-dependent pumping costs. These <span class="hlt">dynamic</span> pumping costs strongly affect the total costs and can lead to non-convexity of the future cost function. The water user groups (agriculture, industry, domestic) are characterized by inelastic demands and fixed water allocation and water supply curtailment costs. As in traditional SDP approaches, one step-ahead sub-problems are solved to find the <span class="hlt">optimal</span> management at any time knowing the inflow scenario and reservoir/aquifer storage levels. These non-linear sub-problems are solved using a genetic algorithm (GA) that minimizes the sum of the immediate and future costs for given surface water reservoir and groundwater aquifer end storages. The immediate cost is found by solving a simple linear allocation sub-problem, and the future costs are assessed by interpolation in the total cost matrix from the following time step. Total costs for all stages, reservoir states, and inflow scenarios are used as future costs to drive a forward moving simulation under uncertain water availability. The use of a GA to solve the sub-problems is computationally more costly than a traditional SDP approach with linearly interpolated future costs. However, in a two-reservoir system the future cost function would have to be represented by a set of planes, and strict convexity in both the surface water and groundwater dimension cannot be maintained. The <span class="hlt">optimization</span> framework based on the GA is still computationally feasible and represents a clean and customizable method. The method has been applied to the Ziya River basin, China. The basin is located on the North China Plain and is subject to severe water scarcity, which includes surface water droughts and groundwater over-pumping. The head-dependent groundwater pumping costs will enable assessment of the long-term effects of increased electricity prices on the groundwater pumping. The coupled <span class="hlt">optimization</span> framework is used to assess realistic alternative development scenarios for the basin. In particular the potential for using electricity pricing policies to reach sustainable groundwater pumping is investigated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1223463','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1223463"><span id="translatedtitle">Progress on <span class="hlt">Optimization</span> of the Nonlinear Beam <span class="hlt">Dynamics</span> in the MEIC Collider Rings</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Morozov, Vasiliy S.; Derbenev, Yaroslav S.; Lin, Fanglei; Pilat, Fulvia; Zhang, Yuhong; Cai, Y.; Nosochkov, Y. M.; Sullivan, Michael; Wang, M.-H.; Wienands, Uli</p> <p>2015-09-01</p> <p>One of the key design features of the Medium-energy Electron-Ion Collider (MEIC) proposed by Jefferson Lab is a small beta function at the interaction point (IP) allowing one to achieve a high luminosity of up to 1034 cm-2s-1. The required strong beam focusing unavoidably causes large chromatic effects such as chromatic tune spread and beam smear at the IP, which need to be compensated. This paper reports recent progress in our development of a chromaticity correction scheme for the ion ring including <span class="hlt">optimization</span> of <span class="hlt">dynamic</span> aperture and momentum acceptance.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1209122','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1209122"><span id="translatedtitle">Progress on <span class="hlt">optimization</span> of the nonlinear beam <span class="hlt">dynamics</span> in the MEIC collider rings</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>None, None</p> <p>2015-07-13</p> <p>One of the key design features of the Medium-energy Electron-Ion Collider (MEIC) proposed by Jefferson Lab is a small beta function at the interaction point (IP) allowing one to achieve a high luminosity of up to 10<sup>34</sup> cm<sup>-2</sup>s<sup>-1</sup>. The required strong beam focusing unavoidably causes large chromatic effects such as chromatic tune spread and beam smear at the IP, which need to be compensated. This paper reports recent progress in our development of a chromaticity correction scheme for the ion ring including <span class="hlt">optimization</span> of <span class="hlt">dynamic</span> aperture and momentum acceptance.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011PhRvE..83c1927B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011PhRvE..83c1927B"><span id="translatedtitle">Riemannian geometric approach to human arm <span class="hlt">dynamics</span>, movement <span class="hlt">optimization</span>, and invariance</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Biess, Armin; Flash, Tamar; Liebermann, Dario G.</p> <p>2011-03-01</p> <p>We present a generally covariant formulation of human arm <span class="hlt">dynamics</span> and <span class="hlt">optimization</span> principles in Riemannian configuration space. We extend the one-parameter family of mean-squared-derivative (MSD) cost functionals from Euclidean to Riemannian space, and we show that they are mathematically identical to the corresponding <span class="hlt">dynamic</span> costs when formulated in a Riemannian space equipped with the kinetic energy metric. In particular, we derive the equivalence of the minimum-jerk and minimum-torque change models in this metric space. Solutions of the one-parameter family of MSD variational problems in Riemannian space are given by (reparametrized) geodesic paths, which correspond to movements with least muscular effort. Finally, movement invariants are derived from symmetries of the Riemannian manifold. We argue that the geometrical structure imposed on the arm’s configuration space may provide insights into the emerging properties of the movements generated by the motor system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012PhPro..33..827M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012PhPro..33..827M"><span id="translatedtitle"><span class="hlt">Optimization</span> for Hub-and-Spoke Port Logistics Network of <span class="hlt">Dynamic</span> Hinterland</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ming-Jun, Ji; Yan-Ling, Chu</p> <p></p> <p>The port logistics and its regional economic react on each other and develop in unison. This paper studies the Hub-and-Spoke port logistics network which is a transportation system between the sea routes and ports hinterland transport routes. An <span class="hlt">optimization</span> model is proposed with the objective of the total transportation cost in the regional port group based on the conditions of <span class="hlt">dynamic</span> hinterland. This paper not only ensures every port in the hub-and spoke port logistics network to achieve its maximum economic benefits, but also makes the entire system get the minimum total transportation cost in the view of quantitative point. In order to illustrate the validity of the model, the example was solved. The results show that the model is feasible. Furthermore, the competitiveness power of the port, the demarcation of hinterland and the traffic capacity are changed <span class="hlt">dynamically</span> in the model, which is closer to the real system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016CoPhC.198...82Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016CoPhC.198...82Z"><span id="translatedtitle">Efficiency <span class="hlt">optimization</span> of a fast Poisson solver in beam <span class="hlt">dynamics</span> simulation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zheng, Dawei; Pöplau, Gisela; van Rienen, Ursula</p> <p>2016-01-01</p> <p>Calculating the solution of Poisson's equation relating to space charge force is still the major time consumption in beam <span class="hlt">dynamics</span> simulations and calls for further improvement. In this paper, we summarize a classical fast Poisson solver in beam <span class="hlt">dynamics</span> simulations: the integrated Green's function method. We introduce three <span class="hlt">optimization</span> steps of the classical Poisson solver routine: using the reduced integrated Green's function instead of the integrated Green's function; using the discrete cosine transform instead of discrete Fourier transform for the Green's function; using a novel fast convolution routine instead of an explicitly zero-padded convolution. The new Poisson solver routine preserves the advantages of fast computation and high accuracy. This provides a fast routine for high performance calculation of the space charge effect in accelerators.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24945778','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24945778"><span id="translatedtitle"><span class="hlt">Optimal</span> control of transient <span class="hlt">dynamics</span> in balanced networks supports generation of complex movements.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hennequin, Guillaume; Vogels, Tim P; Gerstner, Wulfram</p> <p>2014-06-18</p> <p>Populations of neurons in motor cortex engage in complex transient <span class="hlt">dynamics</span> of large amplitude during the execution of limb movements. Traditional network models with stochastically assigned synapses cannot reproduce this behavior. Here we introduce a class of cortical architectures with strong and random excitatory recurrence that is stabilized by intricate, fine-tuned inhibition, <span class="hlt">optimized</span> from a control theory perspective. Such networks transiently amplify specific activity states and can be used to reliably execute multidimensional movement patterns. Similar to the experimental observations, these transients must be preceded by a steady-state initialization phase from which the network relaxes back into the background state by way of complex internal <span class="hlt">dynamics</span>. In our networks, excitation and inhibition are as tightly balanced as recently reported in experiments across several brain areas, suggesting inhibitory control of complex excitatory recurrence as a generic organizational principle in cortex. PMID:24945778</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/17618012','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/17618012"><span id="translatedtitle">An <span class="hlt">optimal</span> <span class="hlt">dynamic</span> inversion-based neuro-adaptive approach for treatment of chronic myelogenous leukemia.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Padhi, Radhakant; Kothari, Mangal</p> <p>2007-09-01</p> <p>Combining the advanced techniques of <span class="hlt">optimal</span> <span class="hlt">dynamic</span> inversion and model-following neuro-adaptive control design, an innovative technique is presented to design an automatic drug administration strategy for effective treatment of chronic myelogenous leukemia (CML). A recently developed nonlinear mathematical model for cell <span class="hlt">dynamics</span> is used to design the controller (medication dosage). First, a nominal controller is designed based on the principle of <span class="hlt">optimal</span> <span class="hlt">dynamic</span> inversion. This controller can treat the nominal model patients (patients who can be described by the mathematical model used here with the nominal parameter values) effectively. However, since the system parameters for a realistic model patient can be different from that of the nominal model patients, simulation studies for such patients indicate that the nominal controller is either inefficient or, worse, ineffective; i.e. the trajectory of the number of cancer cells either shows non-satisfactory transient behavior or it grows in an unstable manner. Hence, to make the drug dosage history more realistic and patient-specific, a model-following neuro-adaptive controller is augmented to the nominal controller. In this adaptive approach, a neural network trained online facilitates a new adaptive controller. The training process of the neural network is based on Lyapunov stability theory, which guarantees both stability of the cancer cell <span class="hlt">dynamics</span> as well as boundedness of the network weights. From simulation studies, this adaptive control design approach is found to be very effective to treat the CML disease for realistic patients. Sufficient generality is retained in the mathematical developments so that the technique can be applied to other similar nonlinear control design problems as well. PMID:17618012</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=branch+AND+bound&id=EJ720501','ERIC'); return false;" href="http://eric.ed.gov/?q=branch+AND+bound&id=EJ720501"><span id="translatedtitle"><span class="hlt">Optimal</span> Least-Squares Unidimensional Scaling: Improved Branch-and-Bound Procedures and Comparison to <span class="hlt">Dynamic</span> Programming</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Brusco, Michael J.; Stahl, Stephanie</p> <p>2005-01-01</p> <p>There are two well-known methods for obtaining a guaranteed globally <span class="hlt">optimal</span> solution to the problem of least-squares unidimensional scaling of a symmetric dissimilarity matrix: (a) <span class="hlt">dynamic</span> programming, and (b) branch-and-bound. <span class="hlt">Dynamic</span> programming is generally more efficient than branch-and-bound, but the former is limited to matrices with…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=dynamic+AND+programming&id=EJ720501','ERIC'); return false;" href="http://eric.ed.gov/?q=dynamic+AND+programming&id=EJ720501"><span id="translatedtitle"><span class="hlt">Optimal</span> Least-Squares Unidimensional Scaling: Improved Branch-and-Bound Procedures and Comparison to <span class="hlt">Dynamic</span> Programming</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Brusco, Michael J.; Stahl, Stephanie</p> <p>2005-01-01</p> <p>There are two well-known methods for obtaining a guaranteed globally <span class="hlt">optimal</span> solution to the problem of least-squares unidimensional scaling of a symmetric dissimilarity matrix: (a) <span class="hlt">dynamic</span> programming, and (b) branch-and-bound. <span class="hlt">Dynamic</span> programming is generally more efficient than branch-and-bound, but the former is limited to matrices with</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25375568','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25375568"><span id="translatedtitle">Network <span class="hlt">dynamics</span> for <span class="hlt">optimal</span> compressive-sensing input-signal recovery.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Barranca, Victor J; Kovačič, Gregor; Zhou, Douglas; Cai, David</p> <p>2014-10-01</p> <p>By using compressive sensing (CS) theory, a broad class of static signals can be reconstructed through a sequence of very few measurements in the framework of a linear system. For networks with nonlinear and time-evolving <span class="hlt">dynamics</span>, is it similarly possible to recover an unknown input signal from only a small number of network output measurements? We address this question for pulse-coupled networks and investigate the network <span class="hlt">dynamics</span> necessary for successful input signal recovery. Determining the specific network characteristics that correspond to a minimal input reconstruction error, we are able to achieve high-quality signal reconstructions with few measurements of network output. Using various measures to characterize <span class="hlt">dynamical</span> properties of network output, we determine that networks with highly variable and aperiodic output can successfully encode network input information with high fidelity and achieve the most accurate CS input reconstructions. For time-varying inputs, we also find that high-quality reconstructions are achievable by measuring network output over a relatively short time window. Even when network inputs change with time, the same <span class="hlt">optimal</span> choice of network characteristics and corresponding <span class="hlt">dynamics</span> apply as in the case of static inputs. PMID:25375568</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4072519','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4072519"><span id="translatedtitle"><span class="hlt">Optimal</span> Reaction Coordinate as a Biomarker for the <span class="hlt">Dynamics</span> of Recovery from Kidney Transplant</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Krivov, Sergei V.; Fenton, Hayley; Goldsmith, Paul J.; Prasad, Rajendra K.; Fisher, Julie; Paci, Emanuele</p> <p>2014-01-01</p> <p>The evolution of disease or the progress of recovery of a patient is a complex process, which depends on many factors. A quantitative description of this process in real-time by a single, clinically measurable parameter (biomarker) would be helpful for early, informed and targeted treatment. Organ transplantation is an eminent case in which the evolution of the post-operative clinical condition is highly dependent on the individual case. The quality of management and monitoring of patients after kidney transplant often determines the long-term outcome of the graft. Using NMR spectra of blood samples, taken at different time points from just before to a week after surgery, we have shown that a biomarker can be found that quantitatively monitors the evolution of a clinical condition. We demonstrate that this is possible if the <span class="hlt">dynamics</span> of the process is considered explicitly: the biomarker is defined and determined as an <span class="hlt">optimal</span> reaction coordinate that provides a quantitatively accurate description of the stochastic recovery <span class="hlt">dynamics</span>. The method, originally developed for the analysis of protein folding <span class="hlt">dynamics</span>, is rigorous, robust and general, i.e., it can be applied in principle to analyze any type of biological <span class="hlt">dynamics</span>. Such predictive biomarkers will promote improvement of long-term graft survival after renal transplantation, and have potentially unlimited applications as diagnostic tools. PMID:24967678</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhRvE..90d2908B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhRvE..90d2908B"><span id="translatedtitle">Network <span class="hlt">dynamics</span> for <span class="hlt">optimal</span> compressive-sensing input-signal recovery</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Barranca, Victor J.; Kovačič, Gregor; Zhou, Douglas; Cai, David</p> <p>2014-10-01</p> <p>By using compressive sensing (CS) theory, a broad class of static signals can be reconstructed through a sequence of very few measurements in the framework of a linear system. For networks with nonlinear and time-evolving <span class="hlt">dynamics</span>, is it similarly possible to recover an unknown input signal from only a small number of network output measurements? We address this question for pulse-coupled networks and investigate the network <span class="hlt">dynamics</span> necessary for successful input signal recovery. Determining the specific network characteristics that correspond to a minimal input reconstruction error, we are able to achieve high-quality signal reconstructions with few measurements of network output. Using various measures to characterize <span class="hlt">dynamical</span> properties of network output, we determine that networks with highly variable and aperiodic output can successfully encode network input information with high fidelity and achieve the most accurate CS input reconstructions. For time-varying inputs, we also find that high-quality reconstructions are achievable by measuring network output over a relatively short time window. Even when network inputs change with time, the same <span class="hlt">optimal</span> choice of network characteristics and corresponding <span class="hlt">dynamics</span> apply as in the case of static inputs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25820090','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25820090"><span id="translatedtitle">Adaptive control schemes for improving <span class="hlt">dynamic</span> performance of efficiency-<span class="hlt">optimized</span> induction motor drives.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kumar, Navneet; Raj Chelliah, Thanga; Srivastava, S P</p> <p>2015-07-01</p> <p>Model Based Control (MBC) is one of the energy <span class="hlt">optimal</span> controllers used in vector-controlled Induction Motor (IM) for controlling the excitation of motor in accordance with torque and speed. MBC offers energy conservation especially at part-load operation, but it creates ripples in torque and speed during load transition, leading to poor <span class="hlt">dynamic</span> performance of the drive. This study investigates the opportunity for improving <span class="hlt">dynamic</span> performance of a three-phase IM operating with MBC and proposes three control schemes: (i) MBC with a low pass filter (ii) torque producing current (iqs) injection in the output of speed controller (iii) Variable Structure Speed Controller (VSSC). The pre and post operation of MBC during load transition is also analyzed. The <span class="hlt">dynamic</span> performance of a 1-hp, three-phase squirrel-cage IM with mine-hoist load diagram is tested. Test results are provided for the conventional field-oriented (constant flux) control and MBC (adjustable excitation) with proposed schemes. The effectiveness of proposed schemes is also illustrated for parametric variations. The test results and subsequent analysis confer that the motor <span class="hlt">dynamics</span> improves significantly with all three proposed schemes in terms of overshoot/undershoot peak amplitude of torque and DC link power in addition to energy saving during load transitions. PMID:25820090</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AdWR...62...90M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AdWR...62...90M"><span id="translatedtitle"><span class="hlt">Optimization</span> of stomatal conductance for maximum carbon gain under <span class="hlt">dynamic</span> soil moisture</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Manzoni, Stefano; Vico, Giulia; Palmroth, Sari; Porporato, Amilcare; Katul, Gabriel</p> <p>2013-12-01</p> <p><span class="hlt">Optimization</span> theories explain a variety of forms and functions in plants. At the leaf scale, it is often hypothesized that carbon gain is maximized, thus providing a quantifiable objective for a mathematical definition of <span class="hlt">optimality</span> conditions. Eco-physiological trade-offs and limited resource availability introduce natural bounds to this <span class="hlt">optimization</span> process. In particular, carbon uptake from the atmosphere is inherently linked to water losses from the soil as water is taken up by roots and evaporated. Hence, water availability in soils constrains the amount of carbon that can be taken up and assimilated into new biomass. The problem of maximizing photosynthesis at a given water availability by modifying stomatal conductance, the plant-controlled variable to be <span class="hlt">optimized</span>, has been traditionally formulated for short time intervals over which soil moisture changes can be neglected. This simplification led to a mathematically open solution, where the undefined Lagrange multiplier of the <span class="hlt">optimization</span> (equivalent to the marginal water use efficiency, λ) is then heuristically determined via data fitting. Here, a set of models based on different assumptions that account for soil moisture <span class="hlt">dynamics</span> over an individual dry-down are proposed so as to provide closed analytical expressions for the carbon gain maximization problem. These novel solutions link the observed variability in λ over time, across soil moisture changes, and at different atmospheric CO2 concentrations to water use strategies ranging from intensive, in which all soil water is consumed by the end of the dry-down period, to more conservative, in which water stress is avoided by reducing transpiration.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/808543','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/808543"><span id="translatedtitle"><span class="hlt">Dynamic</span> <span class="hlt">optimization</span> for commercialization of renewable energy: an example for solar photovoltaics</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Richards, Kenneth, R.; Ashton, W. Bradley; McVeigh, James</p> <p>2000-04-21</p> <p>There are several studies of <span class="hlt">optimal</span> allocation of research and development resources over the time horizon of a project. The primary result of the basic noncompetitive models in this literature is that the <span class="hlt">optimal</span> strategy is to choose a research intensity and ending date for the project such that the marginal costs of accelerating the project equals the marginal benefits of introducing the product sooner. This literature provides useful insights for the government planner who must allocate R&D resources for renewable energy development. However, several characteristics distinguish the process from the typical R&D planning problem. Specifically, with PV development, where the goal is to maximize the net present value of activities leading to cost reduction in commercial modules, there are (1) significant lag-times between investment in laboratory research and resulting effects in the marketplace, (2) a learning curve associated with the manufacturing process that also reduces the cost s of PV modules, (3) interim benefits from technical advances, (4) no clear end point to the R&D process, but rather a tapering off of the value of advances in technical efficiency, (5) significant uncertainty in the R&D process, (6) a family of products rather than an individual technology, (7) a co-mingling of government and private resources with implications for efficient management. A <span class="hlt">dynamic</span> model is developed to characterize the <span class="hlt">optimal</span> intensity and timing of government and private resource allocation for basic research in improving the technical efficiency of cells and subsidies to the manufacturing process to encourage progress on the learning curve. A series of propositions regarding <span class="hlt">optimal</span> paths for each are examined. While the research is purely analytical, the results are useful for conceptualizing the R&D planning process. They also provide a basis for a numerical study that can address whether current levels and historic patterns of funding are <span class="hlt">optimal</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016IJEEP..17..143X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016IJEEP..17..143X"><span id="translatedtitle">The <span class="hlt">Optimized</span> Operation of Gas Turbine Combined Heat and Power Units Oriented for the Grid-Connected Control</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xia, Shu; Ge, Xiaolin</p> <p>2016-04-01</p> <p>In this study, according to various grid-connected demands, the <span class="hlt">optimization</span> scheduling models of Combined Heat and Power (CHP) units are established with three scheduling modes, which are tracking the total generation scheduling mode, tracking steady output scheduling mode and tracking peaking curve scheduling mode. In order to reduce the solution difficulty, based on the principles of modern algebraic integers, linearizing techniques are developed to handle complex nonlinear constrains of the variable conditions, and the <span class="hlt">optimized</span> operation problem of CHP units is converted into a <span class="hlt">mixed-integer</span> linear programming problem. Finally, with specific examples, the 96 points day ahead, heat and power supply plans of the systems are <span class="hlt">optimized</span>. The results show that, the proposed models and methods can develop appropriate coordination heat and power <span class="hlt">optimization</span> programs according to different grid-connected control.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..DFDH15001S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..DFDH15001S"><span id="translatedtitle"><span class="hlt">Optimization</span> of <span class="hlt">dynamic</span> roughness elements for reducing drag in a laminar boundary layer</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sayadi, Taraneh; Sayadi, Peter</p> <p>2015-11-01</p> <p>Roughness elements can serve as controllers in both laminar and turbulent regimes to, for example, reduce the skin friction or drag. In this study, adjoint-based <span class="hlt">optimization</span> is employed to extract the <span class="hlt">optimal</span> shape of roughness elements for reducing drag, in a laminar setting, given an initial condition. The roughness elements considered here are of the ``<span class="hlt">dynamic</span>'' type, varying both in space and time, which allows control over the spatial distribution of the roughness but also the inherent timescales of the flow. <span class="hlt">Dynamic</span> roughness is modeled here using the linearized boundary conditions previously introduced by McKeon (2008), where the no-slip and impermeability boundary conditions are replaced by stream-wise and wall-normal distributions at the wall. The adjoint equation is then implemented using the discretized approach by Fosas et al. (2012). This approach is particularly efficient, since the linearized operators are computed simply by using the local differentiation technique, without explicitly forming the resulting matrices for both forward and adjoint operators. Using the described framework we investigate the effect of the initial condition on the spatial distribution of the roughness elements and their variation in time as the drag coefficient is minimized.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4215892','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4215892"><span id="translatedtitle">Fluid-<span class="hlt">Dynamic</span> <span class="hlt">Optimal</span> Design of Helical Vascular Graft for Stenotic Disturbed Flow</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ha, Hojin; Hwang, Dongha; Choi, Woo-Rak; Baek, Jehyun; Lee, Sang Joon</p> <p>2014-01-01</p> <p>Although a helical configuration of a prosthetic vascular graft appears to be clinically beneficial in suppressing thrombosis and intimal hyperplasia, an <span class="hlt">optimization</span> of a helical design has yet to be achieved because of the lack of a detailed understanding on hemodynamic features in helical grafts and their fluid <span class="hlt">dynamic</span> influences. In the present study, the swirling flow in a helical graft was hypothesized to have beneficial influences on a disturbed flow structure such as stenotic flow. The characteristics of swirling flows generated by helical tubes with various helical pitches and curvatures were investigated to prove the hypothesis. The fluid <span class="hlt">dynamic</span> influences of these helical tubes on stenotic flow were quantitatively analysed by using a particle image velocimetry technique. Results showed that the swirling intensity and helicity of the swirling flow have a linear relation with a modified Germano number (Gn*) of the helical pipe. In addition, the swirling flow generated a beneficial flow structure at the stenosis by reducing the size of the recirculation flow under steady and pulsatile flow conditions. Therefore, the beneficial effects of a helical graft on the flow field can be estimated by using the magnitude of Gn*. Finally, an <span class="hlt">optimized</span> helical design with a maximum Gn* was suggested for the future design of a vascular graft. PMID:25360705</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1991AcAau..25..449Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1991AcAau..25..449Z"><span id="translatedtitle"><span class="hlt">Optimization</span> of a Cassegrainian collector/receiver system for solar-<span class="hlt">dynamic</span> space power generation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zörner, W.; Sedlmair, W.; Blumenberg, J.</p> <p></p> <p>This paper describes the <span class="hlt">optimization</span> of a Cassegrainian collector/receiver system to be used in a solar-<span class="hlt">dynamic</span> power module for a space station. After an introduction to solar-<span class="hlt">dynamic</span> space power generation and its various alternatives of solar collectors, the Cassegrainian collector/receiver system is described in more detail, its advantages are outlined. Because a useful numeric tool for analysing the double reflector Cassegrainian collector/receiver system was not available, a computer code was developed. The code allows the variable modelling of the collector, the receiver, includes solar limb darkening effects, and offers the possibility to make realistic assumptions for collector/receiver system errors. Hence, this computer code sets the ground for real-life operation simulation. The exact knowledge of the intensity distribution in the receiver aperture plane and the receiver interior is indispensable for aperture <span class="hlt">optimization</span> and receiver simulation and design. These intensity distributions are supplied by the computer program. Results of a sensitivity analysis are presented and discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JMagR.227...57V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JMagR.227...57V"><span id="translatedtitle"><span class="hlt">Dynamic</span> nuclear polarization and <span class="hlt">optimal</span> control spatial-selective 13C MRI and MRS</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vinding, Mads S.; Laustsen, Christoffer; Maximov, Ivan I.; Søgaard, Lise Vejby; Ardenkjær-Larsen, Jan H.; Nielsen, Niels Chr.</p> <p>2013-02-01</p> <p>Aimed at 13C metabolic magnetic resonance imaging (MRI) and spectroscopy (MRS) applications, we demonstrate that <span class="hlt">dynamic</span> nuclear polarization (DNP) may be combined with <span class="hlt">optimal</span> control 2D spatial selection to simultaneously obtain high sensitivity and well-defined spatial restriction. This is achieved through the development of spatial-selective single-shot spiral-readout MRI and MRS experiments combined with <span class="hlt">dynamic</span> nuclear polarization hyperpolarized [1-13C]pyruvate on a 4.7 T pre-clinical MR scanner. The method stands out from related techniques by facilitating anatomic shaped region-of-interest (ROI) single metabolite signals available for higher image resolution or single-peak spectra. The 2D spatial-selective rf pulses were designed using a novel Krotov-based <span class="hlt">optimal</span> control approach capable of iteratively fast providing successful pulse sequences in the absence of qualified initial guesses. The technique may be important for early detection of abnormal metabolism, monitoring disease progression, and drug research.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1014686','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1014686"><span id="translatedtitle">Reduced-order model for <span class="hlt">dynamic</span> <span class="hlt">optimization</span> of pressure swing adsorption processes</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Agarwal, A.; Biegler, L.; Zitney, S.</p> <p>2007-01-01</p> <p>Over the past decades, pressure swing adsorption (PSA) processes have been widely used as energy-efficient gas and liquid separation techniques, especially for high purity hydrogen purification from refinery gases. The separation processes are based on solid-gas equilibrium and operate under periodic transient conditions. Models for PSA processes are therefore multiple instances of partial differential equations (PDEs) in time and space with periodic boundary conditions that link the processing steps together. The solution of this coupled stiff PDE system is governed by steep concentrations and temperature fronts moving with time. As a result, the <span class="hlt">optimization</span> of such systems for either design or operation represents a significant computational challenge to current differential algebraic equation (DAE) <span class="hlt">optimization</span> techniques and nonlinear programming algorithms. Model reduction is one approach to generate cost-efficient low-order models which can be used as surrogate models in the <span class="hlt">optimization</span> problems. The study develops a reduced-order model (ROM) based on proper orthogonal decomposition (POD), which is a low-dimensional approximation to a <span class="hlt">dynamic</span> PDE-based model. Initially, a representative ensemble of solutions of the <span class="hlt">dynamic</span> PDE system is constructed by solving a higher-order discretization of the model using the method of lines, a two-stage approach that discretizes the PDEs in space and then integrates the resulting DAEs over time. Next, the ROM method applies the Karhunen-Loeve expansion to derive a small set of empirical eigenfunctions (POD modes) which are used as basis functions within a Galerkin's projection framework to derive a low-order DAE system that accurately describes the dominant <span class="hlt">dynamics</span> of the PDE system. The proposed method leads to a DAE system of significantly lower order, thus replacing the one obtained from spatial discretization before and making <span class="hlt">optimization</span> problem computationally-efficient. The method has been applied to the <span class="hlt">dynamic</span> coupled PDE-based model of a two-bed four-step PSA process for separation of hydrogen from methane. Separate ROMs have been developed for each operating step with different POD modes for each of them. A significant reduction in the order of the number of states has been achieved. The gas-phase mole fraction, solid-state loading and temperature profiles from the low-order ROM and from the high-order simulations have been compared. Moreover, the profiles for a different set of inputs and parameter values fed to the same ROM were compared with the accurate profiles from the high-order simulations. Current results indicate the proposed ROM methodology as a promising surrogate modeling technique for cost-effective <span class="hlt">optimization</span> purposes. Moreover, deviations from the ROM for different set of inputs and parameters suggest that a recalibration of the model is required for the <span class="hlt">optimization</span> studies. Results for these will also be presented with the aforementioned results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26895721','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26895721"><span id="translatedtitle">A <span class="hlt">dynamic</span> simulation/<span class="hlt">optimization</span> model for scheduling restoration of degraded military training lands.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Önal, Hayri; Woodford, Philip; Tweddale, Scott A; Westervelt, James D; Chen, Mengye; Dissanayake, Sahan T M; Pitois, Gauthier</p> <p>2016-04-15</p> <p>Intensive use of military vehicles on Department of Defense training installations causes deterioration in ground surface quality. Degraded lands restrict the scheduled training activities and jeopardize personnel and equipment safety. We present a simulation-<span class="hlt">optimization</span> approach and develop a discrete <span class="hlt">dynamic</span> <span class="hlt">optimization</span> model to determine an optimum land restoration for a given training schedule and availability of financial resources to minimize the adverse effects of training on military lands. The model considers weather forecasts, scheduled maneuver exercises, and unique qualities and importance of the maneuver areas. An application of this approach to Fort Riley, Kansas, shows that: i) starting with natural conditions, the total amount of training damages would increase almost linearly and exceed a quarter of the training area and 228 gullies would be formed (mostly in the intensive training areas) if no restoration is carried out over 10 years; ii) assuming an initial state that resembles the present conditions, sustaining the landscape requires an annual restoration budget of $957 thousand; iii) targeting a uniform distribution of maneuver damages would increase the total damages and adversely affect the overall landscape quality, therefore a selective restoration strategy may be preferred; and iv) a proactive restoration strategy would be <span class="hlt">optimal</span> where land degradations are repaired before they turn into more severe damages that are more expensive to repair and may pose a higher training risk. The last finding can be used as a rule-of-thumb for land restoration efforts in other installations with similar characteristics. PMID:26895721</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4121257','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4121257"><span id="translatedtitle"><span class="hlt">Dynamic</span> Response and <span class="hlt">Optimal</span> Design of Curved Metallic Sandwich Panels under Blast Loading</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Yang, Shu; Han, Shou-Hong; Lu, Zhen-Hua</p> <p>2014-01-01</p> <p>It is important to understand the effect of curvature on the blast response of curved structures so as to seek the <span class="hlt">optimal</span> configurations of such structures with improved blast resistance. In this study, the <span class="hlt">dynamic</span> response and protective performance of a type of curved metallic sandwich panel subjected to air blast loading were examined using LS-DYNA. The numerical methods were validated using experimental data in the literature. The curved panel consisted of an aluminum alloy outer face and a rolled homogeneous armour (RHA) steel inner face in addition to a closed-cell aluminum foam core. The results showed that the configuration of a “soft” outer face and a “hard” inner face worked well for the curved sandwich panel against air blast loading in terms of maximum deflection (MaxD) and energy absorption. The panel curvature was found to have a monotonic effect on the specific energy absorption (SEA) and a nonmonotonic effect on the MaxD of the panel. Based on artificial neural network (ANN) metamodels, multiobjective <span class="hlt">optimization</span> designs of the panel were carried out. The <span class="hlt">optimization</span> results revealed the trade-off relationships between the blast-resistant and the lightweight objectives and showed the great use of Pareto front in such design circumstances. PMID:25126606</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014OcDyn.tmp...87L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014OcDyn.tmp...87L"><span id="translatedtitle">Time-<span class="hlt">optimal</span> path planning in <span class="hlt">dynamic</span> flows using level set equations: theory and schemes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lolla, Tapovan; Lermusiaux, Pierre F. J.; Ueckermann, Mattheus P.; Haley, Patrick J.</p> <p>2014-09-01</p> <p>We develop an accurate partial differential equation-based methodology that predicts the time-<span class="hlt">optimal</span> paths of autonomous vehicles navigating in any continuous, strong, and <span class="hlt">dynamic</span> ocean currents, obviating the need for heuristics. The goal is to predict a sequence of steering directions so that vehicles can best utilize or avoid currents to minimize their travel time. Inspired by the level set method, we derive and demonstrate that a modified level set equation governs the time-<span class="hlt">optimal</span> path in any continuous flow. We show that our algorithm is computationally efficient and apply it to a number of experiments. First, we validate our approach through a simple benchmark application in a Rankine vortex flow for which an analytical solution is available. Next, we apply our methodology to more complex, simulated flow fields such as unsteady double-gyre flows driven by wind stress and flows behind a circular island. These examples show that time-<span class="hlt">optimal</span> paths for multiple vehicles can be planned even in the presence of complex flows in domains with obstacles. Finally, we present and support through illustrations several remarks that describe specific features of our methodology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014OcDyn..64.1373L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014OcDyn..64.1373L"><span id="translatedtitle">Time-<span class="hlt">optimal</span> path planning in <span class="hlt">dynamic</span> flows using level set equations: theory and schemes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lolla, Tapovan; Lermusiaux, Pierre F. J.; Ueckermann, Mattheus P.; Haley, Patrick J.</p> <p>2014-10-01</p> <p>We develop an accurate partial differential equation-based methodology that predicts the time-<span class="hlt">optimal</span> paths of autonomous vehicles navigating in any continuous, strong, and <span class="hlt">dynamic</span> ocean currents, obviating the need for heuristics. The goal is to predict a sequence of steering directions so that vehicles can best utilize or avoid currents to minimize their travel time. Inspired by the level set method, we derive and demonstrate that a modified level set equation governs the time-<span class="hlt">optimal</span> path in any continuous flow. We show that our algorithm is computationally efficient and apply it to a number of experiments. First, we validate our approach through a simple benchmark application in a Rankine vortex flow for which an analytical solution is available. Next, we apply our methodology to more complex, simulated flow fields such as unsteady double-gyre flows driven by wind stress and flows behind a circular island. These examples show that time-<span class="hlt">optimal</span> paths for multiple vehicles can be planned even in the presence of complex flows in domains with obstacles. Finally, we present and support through illustrations several remarks that describe specific features of our methodology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011JChPh.134c4511R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011JChPh.134c4511R"><span id="translatedtitle">Resolution of strongly competitive product channels with <span class="hlt">optimal</span> <span class="hlt">dynamic</span> discrimination: Application to flavins</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Roslund, Jonathan; Roth, Matthias; Guyon, Laurent; Boutou, Véronique; Courvoisier, Francois; Wolf, Jean-Pierre; Rabitz, Herschel</p> <p>2011-01-01</p> <p>Fundamental molecular selectivity limits are probed by exploiting laser-controlled quantum interferences for the creation of distinct spectral signatures in two flavin molecules, erstwhile nearly indistinguishable via steady-state methods. <span class="hlt">Optimal</span> <span class="hlt">dynamic</span> discrimination (ODD) uses <span class="hlt">optimally</span> shaped laser fields to transiently amplify minute molecular variations that would otherwise go unnoticed with linear absorption and fluorescence techniques. ODD is experimentally demonstrated by combining an <span class="hlt">optimally</span> shaped UV pump pulse with a time-delayed, fluorescence-depleting IR pulse for discrimination amongst riboflavin and flavin mononucleotide in aqueous solution, which are structurally and spectroscopically very similar. Closed-loop, adaptive pulse shaping discovers a set of UV pulses that induce disparate responses from the two flavins and allows for concomitant flavin discrimination of ˜16σ. Additionally, attainment of ODD permits quantitative, analytical detection of the individual constituents in a flavin mixture. The successful implementation of ODD on quantum systems of such high complexity bodes well for the future development of the field and the use of ODD techniques in a variety of demanding practical applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25323319','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25323319"><span id="translatedtitle">On <span class="hlt">dynamically</span> generating relevant elementary flux modes in a metabolic network using <span class="hlt">optimization</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Oddsdóttir, Hildur Æsa; Hagrot, Erika; Chotteau, Véronique; Forsgren, Anders</p> <p>2015-10-01</p> <p>Elementary flux modes (EFMs) are pathways through a metabolic reaction network that connect external substrates to products. Using EFMs, a metabolic network can be transformed into its macroscopic counterpart, in which the internal metabolites have been eliminated and only external metabolites remain. In EFMs-based metabolic flux analysis (MFA) experimentally determined external fluxes are used to estimate the flux of each EFM. It is in general prohibitive to enumerate all EFMs for complex networks, since the number of EFMs increases rapidly with network complexity. In this work we present an <span class="hlt">optimization</span>-based method that <span class="hlt">dynamically</span> generates a subset of EFMs and solves the EFMs-based MFA problem simultaneously. The obtained subset contains EFMs that contribute to the <span class="hlt">optimal</span> solution of the EFMs-based MFA problem. The usefulness of our method was examined in a case-study using data from a Chinese hamster ovary cell culture and two networks of varied complexity. It was demonstrated that the EFMs-based MFA problem could be solved at a low computational cost, even for the more complex network. Additionally, only a fraction of the total number of EFMs was needed to compute the <span class="hlt">optimal</span> solution. PMID:25323319</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25126606','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25126606"><span id="translatedtitle"><span class="hlt">Dynamic</span> response and <span class="hlt">optimal</span> design of curved metallic sandwich panels under blast loading.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Qi, Chang; Yang, Shu; Yang, Li-Jun; Han, Shou-Hong; Lu, Zhen-Hua</p> <p>2014-01-01</p> <p>It is important to understand the effect of curvature on the blast response of curved structures so as to seek the <span class="hlt">optimal</span> configurations of such structures with improved blast resistance. In this study, the <span class="hlt">dynamic</span> response and protective performance of a type of curved metallic sandwich panel subjected to air blast loading were examined using LS-DYNA. The numerical methods were validated using experimental data in the literature. The curved panel consisted of an aluminum alloy outer face and a rolled homogeneous armour (RHA) steel inner face in addition to a closed-cell aluminum foam core. The results showed that the configuration of a "soft" outer face and a "hard" inner face worked well for the curved sandwich panel against air blast loading in terms of maximum deflection (MaxD) and energy absorption. The panel curvature was found to have a monotonic effect on the specific energy absorption (SEA) and a nonmonotonic effect on the MaxD of the panel. Based on artificial neural network (ANN) metamodels, multiobjective <span class="hlt">optimization</span> designs of the panel were carried out. The <span class="hlt">optimization</span> results revealed the trade-off relationships between the blast-resistant and the lightweight objectives and showed the great use of Pareto front in such design circumstances. PMID:25126606</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2887054','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2887054"><span id="translatedtitle">Interactive software tool to comprehend the calculation of <span class="hlt">optimal</span> sequence alignments with <span class="hlt">dynamic</span> programming</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ibarra, Ignacio L.; Melo, Francisco</p> <p>2010-01-01</p> <p>Summary: <span class="hlt">Dynamic</span> programming (DP) is a general <span class="hlt">optimization</span> strategy that is successfully used across various disciplines of science. In bioinformatics, it is widely applied in calculating the <span class="hlt">optimal</span> alignment between pairs of protein or DNA sequences. These alignments form the basis of new, verifiable biological hypothesis. Despite its importance, there are no interactive tools available for training and education on understanding the DP algorithm. Here, we introduce an interactive computer application with a graphical interface, for the purpose of educating students about DP. The program displays the DP scoring matrix and the resulting <span class="hlt">optimal</span> alignment(s), while allowing the user to modify key parameters such as the values in the similarity matrix, the sequence alignment algorithm version and the gap opening/extension penalties. We hope that this software will be useful to teachers and students of bioinformatics courses, as well as researchers who implement the DP algorithm for diverse applications. Availability and Implementation: The software is freely available at: http:/melolab.org/sat. The software is written in the Java computer language, thus it runs on all major platforms and operating systems including Windows, Mac OS X and LINUX. Contact: All inquiries or comments about this software should be directed to Francisco Melo at fmelo@bio.puc.cl PMID:20472540</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19880000630','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19880000630"><span id="translatedtitle">Integration of <span class="hlt">dynamic</span>, aerodynamic and structural <span class="hlt">optimization</span> of helicopter rotor blades</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Peters, David A.</p> <p>1987-01-01</p> <p>The purpose of the research is to study the integration of structural, <span class="hlt">dynamic</span>, and aerodynamic considerations in the design-<span class="hlt">optimization</span> process for helicopter rotorblades. This is to be done in three phases. Task 1 is to bring on-line computer codes that could perform the finite-element frequency analyses of rotor blades. The major features of this program are summarized. The second task was to bring on-line an <span class="hlt">optimization</span> code for the work. Several were tried and it was decided to use CONMIN. Explicit volume constraints on the thicknesses and lumped masses used in the <span class="hlt">optimization</span> were added. The specific aeroelastic constraint that the center of mass must be forward of the quarter chord in order to prevent flutter was applied. The bending-torsion coupling due to cg-ea offset within the blade cross section was included. Also included were some very simple stress constraints. The first three constraints are completed, and the fourth constraint is being completed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140010638','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140010638"><span id="translatedtitle">Adaptive Control for Linear Uncertain Systems with Unmodeled <span class="hlt">Dynamics</span> Revisited via <span class="hlt">Optimal</span> Control Modification</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nguyen, Nhan</p> <p>2013-01-01</p> <p>This paper presents the <span class="hlt">optimal</span> control modification for linear uncertain plants. The Lyapunov analysis shows that the modification parameter has a limiting value depending on the nature of the uncertainty. The <span class="hlt">optimal</span> control modification exhibits a linear asymptotic property that enables it to be analyzed in a linear time invariant framework for linear uncertain plants. The linear asymptotic property shows that the closed-loop plants in the limit possess a scaled input-output mapping. Using this property, we can derive an analytical closed-loop transfer function in the limit as the adaptive gain tends to infinity. The paper revisits the Rohrs counterexample problem that illustrates the nature of non-robustness of model-reference adaptive control in the presence of unmodeled <span class="hlt">dynamics</span>. An analytical approach is developed to compute exactly the modification parameter for the <span class="hlt">optimal</span> control modification that stabilizes the plant in the Rohrs counterexample. The linear asymptotic property is also used to address output feedback adaptive control for non-minimum phase plants with a relative degree 1.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JSV...344..416H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JSV...344..416H"><span id="translatedtitle">A parameters <span class="hlt">optimization</span> method for planar joint clearance model and its application for <span class="hlt">dynamics</span> simulation of reciprocating compressor</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hai-yang, Zhao; Min-qiang, Xu; Jin-dong, Wang; Yong-bo, Li</p> <p>2015-05-01</p> <p>In order to improve the accuracy of <span class="hlt">dynamics</span> response simulation for mechanism with joint clearance, a parameter <span class="hlt">optimization</span> method for planar joint clearance contact force model was presented in this paper, and the <span class="hlt">optimized</span> parameters were applied to the <span class="hlt">dynamics</span> response simulation for mechanism with oversized joint clearance fault. By studying the effect of increased clearance on the parameters of joint clearance contact force model, the relation of model parameters between different clearances was concluded. Then the <span class="hlt">dynamic</span> equation of a two-stage reciprocating compressor with four joint clearances was developed using Lagrange method, and a multi-body <span class="hlt">dynamic</span> model built in ADAMS software was used to solve this equation. To obtain a simulated <span class="hlt">dynamic</span> response much closer to that of experimental tests, the parameters of joint clearance model, instead of using the designed values, were <span class="hlt">optimized</span> by genetic algorithms approach. Finally, the <span class="hlt">optimized</span> parameters were applied to simulate the <span class="hlt">dynamics</span> response of model with oversized joint clearance fault according to the concluded parameter relation. The <span class="hlt">dynamics</span> response of experimental test verified the effectiveness of this application.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25502170','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25502170"><span id="translatedtitle">Combating obesity through healthy eating behavior: a call for system <span class="hlt">dynamics</span> <span class="hlt">optimization</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Abidin, Norhaslinda Zainal; Mamat, Mustafa; Dangerfield, Brian; Zulkepli, Jafri Haji; Baten, Md Azizul; Wibowo, Antoni</p> <p>2014-01-01</p> <p>Poor eating behavior has been identified as one of the core contributory factors of the childhood obesity epidemic. The consequences of obesity on numerous aspects of life are thoroughly explored in the existing literature. For instance, evidence shows that obesity is linked to incidences of diseases such as heart disease, type-2 diabetes, and some cancers, as well as psychosocial problems. To respond to the increasing trends in the UK, in 2008 the government set a target to reverse the prevalence of obesity (POB) back to 2000 levels by 2020. This paper will outline the application of system <span class="hlt">dynamics</span> (SD) <span class="hlt">optimization</span> to simulate the effect of changes in the eating behavior of British children (aged 2 to 15 years) on weight and obesity. This study also will identify how long it will take to achieve the government's target. This paper proposed a simulation model called Intervention Childhood Obesity <span class="hlt">Dynamics</span> (ICOD) by focusing the interrelations between various strands of knowledge in one complex human weight regulation system. The model offers distinct insights into the <span class="hlt">dynamics</span> by capturing the complex interdependencies from the causal loop and feedback structure, with the intention to better understand how eating behaviors influence children's weight, body mass index (BMI), and POB measurement. This study proposed a set of equations that are revised from the original (baseline) equations. The new functions are constructed using a RAMP function of linear decrement in portion size and number of meal variables from 2013 until 2020 in order to achieve the 2020 desired target. Findings from the <span class="hlt">optimization</span> analysis revealed that the 2020 target won't be achieved until 2026 at the earliest, six years late. Thus, the model suggested that a longer period may be needed to significantly reduce obesity in this population. PMID:25502170</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4266604','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4266604"><span id="translatedtitle">Combating Obesity through Healthy Eating Behavior: A Call for System <span class="hlt">Dynamics</span> <span class="hlt">Optimization</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Zainal Abidin, Norhaslinda; Mamat, Mustafa; Dangerfield, Brian; Zulkepli, Jafri Haji; Baten, Md. Azizul; Wibowo, Antoni</p> <p>2014-01-01</p> <p>Poor eating behavior has been identified as one of the core contributory factors of the childhood obesity epidemic. The consequences of obesity on numerous aspects of life are thoroughly explored in the existing literature. For instance, evidence shows that obesity is linked to incidences of diseases such as heart disease, type-2 diabetes, and some cancers, as well as psychosocial problems. To respond to the increasing trends in the UK, in 2008 the government set a target to reverse the prevalence of obesity (POB) back to 2000 levels by 2020. This paper will outline the application of system <span class="hlt">dynamics</span> (SD) <span class="hlt">optimization</span> to simulate the effect of changes in the eating behavior of British children (aged 2 to 15 years) on weight and obesity. This study also will identify how long it will take to achieve the government’s target. This paper proposed a simulation model called Intervention Childhood Obesity <span class="hlt">Dynamics</span> (ICOD) by focusing the interrelations between various strands of knowledge in one complex human weight regulation system. The model offers distinct insights into the <span class="hlt">dynamics</span> by capturing the complex interdependencies from the causal loop and feedback structure, with the intention to better understand how eating behaviors influence children’s weight, body mass index (BMI), and POB measurement. This study proposed a set of equations that are revised from the original (baseline) equations. The new functions are constructed using a RAMP function of linear decrement in portion size and number of meal variables from 2013 until 2020 in order to achieve the 2020 desired target. Findings from the <span class="hlt">optimization</span> analysis revealed that the 2020 target won’t be achieved until 2026 at the earliest, six years late. Thus, the model suggested that a longer period may be needed to significantly reduce obesity in this population. PMID:25502170</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PMB....58.8163S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PMB....58.8163S"><span id="translatedtitle">Trajectory <span class="hlt">optimization</span> for <span class="hlt">dynamic</span> couch rotation during volumetric modulated arc radiotherapy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Smyth, Gregory; Bamber, Jeffrey C.; Evans, Philip M.; Bedford, James L.</p> <p>2013-11-01</p> <p>Non-coplanar radiation beams are often used in three-dimensional conformal and intensity modulated radiotherapy to reduce dose to organs at risk (OAR) by geometric avoidance. In volumetric modulated arc radiotherapy (VMAT) non-coplanar geometries are generally achieved by applying patient couch rotations to single or multiple full or partial arcs. This paper presents a trajectory <span class="hlt">optimization</span> method for a non-coplanar technique, <span class="hlt">dynamic</span> couch rotation during VMAT (DCR-VMAT), which combines ray tracing with a graph search algorithm. Four clinical test cases (partial breast, brain, prostate only, and prostate and pelvic nodes) were used to evaluate the potential OAR sparing for trajectory-<span class="hlt">optimized</span> DCR-VMAT plans, compared with standard coplanar VMAT. In each case, ray tracing was performed and a cost map reflecting the number of OAR voxels intersected for each potential source position was generated. The least-cost path through the cost map, corresponding to an <span class="hlt">optimal</span> DCR-VMAT trajectory, was determined using Dijkstra’s algorithm. Results show that trajectory <span class="hlt">optimization</span> can reduce dose to specified OARs for plans otherwise comparable to conventional coplanar VMAT techniques. For the partial breast case, the mean heart dose was reduced by 53%. In the brain case, the maximum lens doses were reduced by 61% (left) and 77% (right) and the globes by 37% (left) and 40% (right). Bowel mean dose was reduced by 15% in the prostate only case. For the prostate and pelvic nodes case, the bowel V50 Gy and V60 Gy were reduced by 9% and 45% respectively. Future work will involve further development of the algorithm and assessment of its performance over a larger number of cases in site-specific cohorts.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6930813','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6930813"><span id="translatedtitle"><span class="hlt">Optimal</span> temporal convolution smoothing for the perception of the recurrent display of a <span class="hlt">dynamic</span> image series</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Vanregemorter, J.; Deconinck, F.</p> <p>1984-01-01</p> <p>The visual perception of temporal changes in a <span class="hlt">dynamic</span> series of images, e.g. a recurrent movie display of an equilibrium gated angiography, depends strongly on the frequency of the changes in activity of the images. The human eye is three times as sensitive for frequencies at about ten hertz, as for frequencies lower than three hertz. This causes a low sensitivity for the relevant activity changes in the information of the series and a much higher sensitivity for activity changes due to noise. Linear combination of subsequent images allows to filter the frequency content of the series at about ten hertz. This does not affect the information of the series as this contains typically frequencies lower than three hertz (about the third harmonic in a typical angiography). For a filter which creates a new series of images by adding three subsequent images with factors a,b and a respectively, the <span class="hlt">optimal</span> ratio A=a/b to reduce frequencies at ten hertz depends on the speed of projection of the <span class="hlt">dynamic</span> series. A projection at 16 images per second leads to A=1.6. The effect of the filter is both objective on the static images (convolution smoothing) and subjective (psychophysical) on the <span class="hlt">dynamic</span> series. It allows the reduction of the fast disturbing changes in the images due to noise and does not affect the diagnostic information in the images.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3498056','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3498056"><span id="translatedtitle">Bouncing between Model and Data: Stability, Passivity, and <span class="hlt">Optimality</span> in Hybrid <span class="hlt">Dynamics</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ronsse, Renaud; Sternad, Dagmar</p> <p>2012-01-01</p> <p>Rhythmically bouncing a ball with a racket is a seemingly simple task, but it poses all the challenges critical for coordinative behavior: perceiving the ball’s trajectory to adapt position and velocity of the racket for the next ball contact. To gain insight into the underlying control strategies, the authors conducted a series of studies that tested models with experimental data, with an emphasis on deriving model-based hypotheses and trying to falsify them. Starting with a simple <span class="hlt">dynamical</span> model of the racket and ball interactions, stability analyses showed that open-loop <span class="hlt">dynamics</span> affords <span class="hlt">dynamical</span> stability, such that small perturbations do not require corrections. To obtain this passive stability, the ball has to be impacted with negative acceleration—a strategy that subjects adopted in a variety of conditions at steady state. However, experimental tests that applied perturbations revealed that after perturbations, subjects applied active perceptually guided corrections to reestablish steady state faster than by relying on the passive model’s relaxation alone. Hence, the authors derived a model with active control based on <span class="hlt">optimality</span> principles that considered each impact as a separate reaching-like movement. This model captured some additional features of the racket trajectory but failed to predict more fine-grained aspects of performance. The authors proceed to present a new model that accounts not only for fine-grained behavior but also reconciles passive and active control approaches with new predictions that will be put to test in the next set of experiments. PMID:21184357</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JMagR.234...75X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JMagR.234...75X"><span id="translatedtitle"><span class="hlt">Optimal</span> variable flip angle schemes for <span class="hlt">dynamic</span> acquisition of exchanging hyperpolarized substrates</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xing, Yan; Reed, Galen D.; Pauly, John M.; Kerr, Adam B.; Larson, Peder E. Z.</p> <p>2013-09-01</p> <p>In metabolic MRI with hyperpolarized contrast agents, the signal levels vary over time due to T1 decay, T2 decay following RF excitations, and metabolic conversion. Efficient usage of the nonrenewable hyperpolarized magnetization requires specialized RF pulse schemes. In this work, we introduce two novel variable flip angle schemes for <span class="hlt">dynamic</span> hyperpolarized MRI in which the flip angle is varied between excitations and between metabolites. These were <span class="hlt">optimized</span> to distribute the magnetization relatively evenly throughout the acquisition by accounting for T1 decay, prior RF excitations, and metabolic conversion. Simulation results are presented to confirm the flip angle designs and evaluate the variability of signal <span class="hlt">dynamics</span> across typical ranges of T1 and metabolic conversion. They were implemented using multiband spectral-spatial RF pulses to independently modulate the flip angle at various chemical shift frequencies. With these schemes we observed increased SNR of [1-13C]lactate generated from [1-13C]pyruvate, particularly at later time points. This will allow for improved characterization of tissue perfusion and metabolic profiles in <span class="hlt">dynamic</span> hyperpolarized MRI.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JSV...351...43R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JSV...351...43R"><span id="translatedtitle">Passive vibration control in rotor <span class="hlt">dynamics</span>: <span class="hlt">Optimization</span> of composed support using viscoelastic materials</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ribeiro, Eduardo Afonso; Pereira, Jucélio Tomás; Alberto Bavastri, Carlos</p> <p>2015-09-01</p> <p>One of the major reasons for inserting damping into bearings is that rotating machines are often requested in critical functioning conditions having sometimes to function under <span class="hlt">dynamic</span> instability or close to critical speeds. Hydrodynamic and magnetic bearings have usually been used for this purpose, but they present limitations regarding costs and operation, rendering the use of viscoelastic supports a feasible solution for vibration control in rotating machines. Most papers in the area use simple analytic or single degree of freedom models for the rotor as well as classic mechanical models of linear viscoelasticity for the support - like Maxwell, Kelvin-Voigt, Zenner, four-element, GHM models and even frequency independent models - but they lack the accuracy of fractional models in a large range of frequency and temperature regarding the same number of coefficients. Even in those works, the need to consider the addition of degrees of freedom to the support is evident. However, so far no paper has been published focusing on a methodology to determine the <span class="hlt">optimal</span> constructive form for any viscoelastic support in which the rotor is discretized by finite elements associated to an accurate model for characterizing the viscoelastic material. In general, the support is meant to be a simple isolation system, and the fact the stiffness matrix is complex and frequency-temperature dependent - due to its viscoelastic properties - forces the traditional methods to require an extremely long computing time, thus rendering them too time consuming in an <span class="hlt">optimization</span> environment. The present work presents a robust methodology based mainly on generalized equivalent parameters (GEP) - for an <span class="hlt">optimal</span> design of viscoelastic supports for rotating machinery - aiming at minimizing the unbalance frequency response of the system using a hybrid <span class="hlt">optimization</span> technique (genetic algorithms and Nelder-Mead method). The rotor is modeled based on the finite element method using Timoshenko's thick beam formulation, and the viscoelastic material is modeled based on four-parameter fractional derivatives. The insertion of supports - a two-degree-of-freedom isolation system - into rotor's motion equations is performed in two different ways: (1) by adding degrees of freedom and (2) by using the GEP technique. The results show that both techniques are consistent, but the GEP technique proves to be less time consuming, regarding computing time. In the presented simulations it is possible to observe the reduction in vibration amplitudes and transmissibility in a system using <span class="hlt">optimized</span> viscoelastic supports when compared to ball and hydrodynamic bearings. One concludes that the methodology presented is robust and allows obtaining an <span class="hlt">optimal</span> design of any viscoelastic support - using GEP - in an efficient and viable way for vibration passive control in rotors of rotating machines.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFM.B21C..02S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFM.B21C..02S"><span id="translatedtitle"><span class="hlt">Optimality</span> Based <span class="hlt">Dynamic</span> Plant Allocation Model: Predicting Acclimation Response to Climate Change</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Srinivasan, V.; Drewry, D.; Kumar, P.; Sivapalan, M.</p> <p>2009-12-01</p> <p>Allocation of assimilated carbon to different plant parts determines the future plant status and is important to predict long term (months to years) vegetated land surface fluxes. Plants have the ability to modify their allometry and exhibit plasticity by varying the relative proportions of the structural biomass contained in each of its tissue. The ability of plants to be plastic provides them with the potential to acclimate to changing environmental conditions in order to enhance their probability of survival. Allometry based allocation models and other empirical allocation models do not account for plant plasticity cause by acclimation due to environmental changes. In the absence of a detailed understanding of the various biophysical processes involved in plant growth and development an <span class="hlt">optimality</span> approach is adopted here to predict carbon allocation in plants. Existing <span class="hlt">optimality</span> based models of plant growth are either static or involve considerable empiricism. In this work, we adopt an <span class="hlt">optimality</span> based approach (coupled with limitations on plant plasticity) to predict the <span class="hlt">dynamic</span> allocation of assimilated carbon to different plant parts. We explore the applicability of this approach using several <span class="hlt">optimization</span> variables such as net primary productivity, net transpiration, realized growth rate, total end of growing season reproductive biomass etc. We use this approach to predict the <span class="hlt">dynamic</span> nature of plant acclimation in its allocation of carbon to different plant parts under current and future climate scenarios. This approach is designed as a growth sub-model in the multi-layer canopy plant model (MLCPM) and is used to obtain land surface fluxes and plant properties over the growing season. The framework of this model is such that it retains the generality and can be applied to different types of ecosystems. We test this approach using the data from free air carbon dioxide enrichment (FACE) experiments using soybean crop at the Soy-FACE research site. Our results show that there are significant changes in the allocation patterns of vegetation when subjected to elevated CO2 indicating that our model is able to account for plant plasticity arising from acclimation. Soybeans when grown under elevated CO2, increased their allocation to structural components such as leaves and decreased their allocation to reproductive biomass. This demonstrates that plant acclimation causes lower than expected crop yields when grown under elevated CO2. Our findings can have serious implications in estimating future crop yields under climate change scenarios where it is widely expected that rising CO2 will fully offset losses due to climate change.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3369909','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3369909"><span id="translatedtitle">Structural and <span class="hlt">Dynamic</span> Requirements for <span class="hlt">Optimal</span> Activity of the Essential Bacterial Enzyme Dihydrodipicolinate Synthase</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Reboul, C. F.; Porebski, B. T.; Griffin, M. D. W.; Dobson, R. C. J.; Perugini, M. A.; Gerrard, J. A.; Buckle, A. M.</p> <p>2012-01-01</p> <p>Dihydrodipicolinate synthase (DHDPS) is an essential enzyme involved in the lysine biosynthesis pathway. DHDPS from E. coli is a homotetramer consisting of a dimer of dimers, with the catalytic residues found at the tight-dimer interface. Crystallographic and biophysical evidence suggest that the dimers associate to stabilise the active site configuration, and mutation of a central dimer-dimer interface residue destabilises the tetramer, thus increasing the flexibility and reducing catalytic efficiency and substrate specificity. This has led to the hypothesis that the tetramer evolved to optimise the <span class="hlt">dynamics</span> within the tight-dimer. In order to gain insights into DHDPS flexibility and its relationship to quaternary structure and function, we performed comparative Molecular <span class="hlt">Dynamics</span> simulation studies of native tetrameric and dimeric forms of DHDPS from E. coli and also the native dimeric form from methicillin-resistant Staphylococcus aureus (MRSA). These reveal a striking contrast between the <span class="hlt">dynamics</span> of tetrameric and dimeric forms. Whereas the E. coli DHDPS tetramer is relatively rigid, both the E. coli and MRSA DHDPS dimers display high flexibility, resulting in monomer reorientation within the dimer and increased flexibility at the tight-dimer interface. The mutant E. coli DHDPS dimer exhibits disorder within its active site with deformation of critical catalytic residues and removal of key hydrogen bonds that render it inactive, whereas the similarly flexible MRSA DHDPS dimer maintains its catalytic geometry and is thus fully functional. Our data support the hypothesis that in both bacterial species <span class="hlt">optimal</span> activity is achieved by fine tuning protein <span class="hlt">dynamics</span> in different ways: E. coli DHDPS buttresses together two dimers, whereas MRSA dampens the motion using an extended tight-dimer interface. PMID:22685390</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012PhDT.......262K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012PhDT.......262K"><span id="translatedtitle">Combinatorial <span class="hlt">Optimization</span> Algorithms for <span class="hlt">Dynamic</span> Multiple Fault Diagnosis in Automotive and Aerospace Applications</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kodali, Anuradha</p> <p></p> <p>In this thesis, we develop <span class="hlt">dynamic</span> multiple fault diagnosis (DMFD) algorithms to diagnose faults that are sporadic and coupled. Firstly, we formulate a coupled factorial hidden Markov model-based (CFHMM) framework to diagnose dependent faults occurring over time (<span class="hlt">dynamic</span> case). Here, we implement a mixed memory Markov coupling model to determine the most likely sequence of (dependent) fault states, the one that best explains the observed test outcomes over time. An iterative Gauss-Seidel coordinate ascent <span class="hlt">optimization</span> method is proposed for solving the problem. A soft Viterbi algorithm is also implemented within the framework for decoding dependent fault states over time. We demonstrate the algorithm on simulated and real-world systems with coupled faults; the results show that this approach improves the correct isolation rate as compared to the formulation where independent fault states are assumed. Secondly, we formulate a generalization of set-covering, termed <span class="hlt">dynamic</span> set-covering (DSC), which involves a series of coupled set-covering problems over time. The objective of the DSC problem is to infer the most probable time sequence of a parsimonious set of failure sources that explains the observed test outcomes over time. The DSC problem is NP-hard and intractable due to the fault-test dependency matrix that couples the failed tests and faults via the constraint matrix, and the temporal dependence of failure sources over time. Here, the DSC problem is motivated from the viewpoint of a <span class="hlt">dynamic</span> multiple fault diagnosis problem, but it has wide applications in operations research, for e.g., facility location problem. Thus, we also formulated the DSC problem in the context of a <span class="hlt">dynamically</span> evolving facility location problem. Here, a facility can be opened, closed, or can be temporarily unavailable at any time for a given requirement of demand points. These activities are associated with costs or penalties, viz., phase-in or phase-out for the opening or closing of a facility, respectively. The set-covering matrix encapsulates the relationship among the rows (tests or demand points) and columns (faults or locations) of the system at each time. By relaxing the coupling constraints using Lagrange multipliers, the DSC problem can be decoupled into independent subproblems, one for each column. Each subproblem is solved using the Viterbi decoding algorithm, and a primal feasible solution is constructed by modifying the Viterbi solutions via a heuristic. The proposed Viterbi-Lagrangian relaxation algorithm (VLRA) provides a measure of suboptimality via an approximate duality gap. As a major practical extension of the above problem, we also consider the problem of diagnosing faults with delayed test outcomes, termed delay-<span class="hlt">dynamic</span> set-covering (DDSC), and experiment with real-world problems that exhibit masking faults. Also, we present simulation results on OR-library datasets (set-covering formulations are predominantly validated on these matrices in the literature), posed as facility location problems. Finally, we implement these algorithms to solve problems in aerospace and automotive applications. Firstly, we address the diagnostic ambiguity problem in aerospace and automotive applications by developing a <span class="hlt">dynamic</span> fusion framework that includes <span class="hlt">dynamic</span> multiple fault diagnosis algorithms. This improves the correct fault isolation rate, while minimizing the false alarm rates, by considering multiple faults instead of the traditional data-driven techniques based on single fault (class)-single epoch (static) assumption. The <span class="hlt">dynamic</span> fusion problem is formulated as a maximum a posteriori decision problem of inferring the fault sequence based on uncertain outcomes of multiple binary classifiers over time. The fusion process involves three steps: the first step transforms the multi-class problem into dichotomies using error correcting output codes (ECOC), thereby solving the concomitant binary classification problems; the second step fuses the outcomes of multiple binary classifiers over time using a sliding window or block <span class="hlt">dynamic</span> fusion method that exploits temporal data correlations over time. We solve this NP-hard <span class="hlt">optimization</span> problem via a Lagrangian relaxation (variational) technique. The third step <span class="hlt">optimizes</span> the classifier parameters, viz., probabilities of detection and false alarm, using a genetic algorithm. The proposed algorithm is demonstrated by computing the diagnostic performance metrics on a twin-spool commercial jet engine, an automotive engine, and UCI datasets (problems with high classification error are specifically chosen for experimentation). We show that the primal-dual <span class="hlt">optimization</span> framework performed consistently better than any traditional fusion technique, even when it is forced to give a single fault decision across a range of classification problems. Secondly, we implement the inference algorithms to diagnose faults in vehicle systems that are controlled by a network of electronic control units (ECUs). The faults, originating from various interactions and especially between hardware and software, are particularly challenging to address. Our basic strategy is to divide the fault universe of such cyber-physical systems in a hierarchical manner, and monitor the critical variables/signals that have impact at different levels of interactions. The proposed diagnostic strategy is validated on an electrical power generation and storage system (EPGS) controlled by two ECUs in an environment with CANoe/MATLAB co-simulation. Eleven faults are injected with the failures originating in actuator hardware, sensor, controller hardware and software components. Diagnostic matrix is established to represent the relationship between the faults and the test outcomes (also known as fault signatures) via simulations. The results show that the proposed diagnostic strategy is effective in addressing the interaction-caused faults.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012PhDT.......167W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012PhDT.......167W"><span id="translatedtitle">Sequentially <span class="hlt">Optimized</span> Meshfree Approximation as a New Computational Fluid <span class="hlt">Dynamics</span> Solver</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wilkinson, Matthew</p> <p></p> <p>This thesis presents the Sequentially <span class="hlt">Optimized</span> Meshfree Approximation (SOMA) method, a new and powerful Computational Fluid <span class="hlt">Dynamics</span> (CFD) solver. While standard computational methods can be faster and cheaper that physical experimentation, both in cost and work time, these methods do have some time and user interaction overhead which SOMA eliminates. As a meshfree method which could use adaptive domain refinement methods, SOMA avoids the need for user generated and/or analyzed grids, volumes, and meshes. Incremental building of a feed-forward artificial neural network through machine learning to solve the flow problem significantly reduces user interaction and reduces computational cost. This is done by avoiding the creation and inversion of possibly dense block diagonal matrices and by focusing computational work on regions where the flow changes and ignoring regions where no changes occur.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26512855','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26512855"><span id="translatedtitle">Hydrodynamic <span class="hlt">optimization</span> of membrane bioreactor by horizontal geometry modification using computational fluid <span class="hlt">dynamics</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yan, Xiaoxu; Wu, Qing; Sun, Jianyu; Liang, Peng; Zhang, Xiaoyuan; Xiao, Kang; Huang, Xia</p> <p>2016-01-01</p> <p>Geometry property would affect the hydrodynamics of membrane bioreactor (MBR), which was directly related to membrane fouling rate. The simulation of a bench-scale MBR by computational fluid <span class="hlt">dynamics</span> (CFD) showed that the shear stress on membrane surface could be elevated by 74% if the membrane was sandwiched between two baffles (baffled MBR), compared with that without baffles (unbaffled MBR). The effects of horizontal geometry characteristics of a bench-scale membrane tank were discussed (riser length index Lr, downcomer length index Ld, tank width index Wt). Simulation results indicated that the average cross flow of the riser was negatively correlated to the ratio of riser and downcomer cross-sectional area. A relatively small tank width would also be preferable in promoting shear stress on membrane surface. The <span class="hlt">optimized</span> MBR had a shear elevation of 21.3-91.4% compared with unbaffled MBR under same aeration intensity. PMID:26512855</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010cosp...38.3385H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010cosp...38.3385H"><span id="translatedtitle">Design and construction of miniature artificial ecosystem based on <span class="hlt">dynamic</span> response <span class="hlt">optimization</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hu, Dawei; Liu, Hong; Tong, Ling; Li, Ming; Hu, Enzhu</p> <p></p> <p>The miniature artificial ecosystem (MAES) is a combination of man, silkworm, salad and mi-croalgae to partially regenerate O2 , sanitary water and food, simultaneously dispose CO2 and wastes, therefore it have a fundamental life support function. In order to enhance the safety and reliability of MAES and eliminate the influences of internal variations and external dis-turbances, it was necessary to configure MAES as a closed-loop control system, and it could be considered as a prototype for future bioregenerative life support system. However, MAES is a complex system possessing large numbers of parameters, intricate nonlinearities, time-varying factors as well as uncertainties, hence it is difficult to perfectly design and construct a prototype through merely conducting experiments by trial and error method. Our research presented an effective way to resolve preceding problem by use of <span class="hlt">dynamic</span> response <span class="hlt">optimiza-tion</span>. Firstly the mathematical model of MAES with first-order nonlinear ordinary differential equations including parameters was developed based on relevant mechanisms and experimental data, secondly simulation model of MAES was derived on the platform of MatLab/Simulink to perform model validation and further digital simulations, thirdly reference trajectories of de-sired <span class="hlt">dynamic</span> response of system outputs were specified according to prescribed requirements, and finally <span class="hlt">optimization</span> for initial values, tuned parameter and independent parameters was carried out using the genetic algorithm, the advanced direct search method along with parallel computing methods through computer simulations. The result showed that all parameters and configurations of MAES were determined after a series of computer experiments, and its tran-sient response performances and steady characteristics closely matched the reference curves. Since the prototype is a physical system that represents the mathematical model with reason-able accuracy, so the process of designing and constructing a prototype of MAES is the reverse of mathematical modeling, and must have prerequisite assists from these results of computer simulation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AcAau.117..209B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AcAau.117..209B"><span id="translatedtitle">Rapid maneuvering of multi-body <span class="hlt">dynamic</span> systems with <span class="hlt">optimal</span> motion compensation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bishop, B.; Gargano, R.; Sears, A.; Karpenko, M.</p> <p>2015-12-01</p> <p>Rapid maneuvering of multi-body <span class="hlt">dynamical</span> systems is an important, yet challenging, problem in many applications. Even in the case of rigid bodies, it can be difficult to maintain precise control over nominally stationary links if it is required to move some of the other links quickly because of the various nonlinearities and coupled interactions that occur between the bodies. Typical control concepts treat the multi-body motion control problem in two-stages. First, the nonlinear and coupling terms are treated as disturbances and a trajectory tracking control law is designed in order to attenuate their effects. Next, motion profiles are designed, based on kinematics parameterizations, and these are used as inputs to the closed loop system to move the links. This paper describes an approach for rapid maneuvering of multi-body systems that uses <span class="hlt">optimal</span> control theory to account for <span class="hlt">dynamic</span> nonlinearities and coupling as part of the motion trajectory design. Incorporating appropriate operational constraints automatically compensates for these multi-body effects so that motion time can be reduced while simultaneously achieving other objectives such as reducing the excitation of selected links. Since the compensatory effect is embedded within the <span class="hlt">optimal</span> motion trajectories, the performance improvement can be obtained even when using simple closed-loop architectures for maneuver implementation. Simulation results for minimum time control of a two-axis gimbal system and for rapid maneuvering of a TDRS single-access antenna, wherein it is desired to limit the excitation of the satellite body to which the antenna is attached, are presented to illustrate the concepts.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005SPIE.5970..913Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005SPIE.5970..913Z"><span id="translatedtitle">A proposal for a semi-<span class="hlt">dynamically</span> reconfigurable optical network <span class="hlt">optimization</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Yiming; Yang, Oliver W. W.</p> <p>2005-09-01</p> <p>The Routing and Wavelength Assignment (RWA) problem has attracted lots of attention in the research field for the past decade. Most of the existing works are the classic static RWA problem, which assumes every time for the reconfiguration, all the existing connections will be reconfigured. In a real operating network, the reconfiguration has to take the existing connections into consideration and any reconfiguration of the existing connection results in the disruption of the upper level traffic. The algorithms that are slow or do not consider the existing connections in the network cannot be used in the real-time reconfigurable network. In this paper, we propose the semi-<span class="hlt">dynamic</span>/static network <span class="hlt">optimization</span> problem that takes into consideration existing connections from the previous reconfiguration session. The objective function in the formulation is penalty-based, i.e., there are penalties for the reconfiguration of a connection, for the rejection of a connection demand and for the most congested link. Rules on the existing capacity and new demand in the new session are proposed. We have successfully used the Lagrange Relaxation (LR) and Subgradient Method to successfully solve this network <span class="hlt">optimization</span> problem. This state-of-art frame work allows us to evaluate systematically some sample networks in terms of various network performances and behaviors. At the same time, excellent algorithm performance and efficient computation complexity are demonstrated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009ccta.conf.1347Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009ccta.conf.1347Z"><span id="translatedtitle"><span class="hlt">Optimal</span> Model on Canal Water Distribution Based on <span class="hlt">Dynamic</span> Penalty Function and Genetic Algorithm</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhao, Wenju; Ma, Xiaoyi; Kang, Yinhong; Ren, Hongyi; Su, Baofeng</p> <p></p> <p>The present <span class="hlt">optimal</span> water delivery scheduling models are based on the assumed equal design discharges of lateral canals, which are not in accordance with practical water delivery scheduling demand in most irrigation systems. In order to solve this problem, a model of lateral canals with unequal discharges and a solution method were proposed; At present, traditional fixed penalty factor have some problem, such as it is difficulty to use unified dimension and to get a higher searching precision, besides, it prematurely converge to local <span class="hlt">optimal</span> solution. Therefore, the thought of simulated annealing was referred to design a <span class="hlt">dynamic</span> penalty function. In the progress of genetic operation, the SGA (Simple Genetic Algorithm) adopted adaptive crossover mutation method, and compared distinct solutions of model which based on the method in this paper, Adaptive genetic algorithm (AGA) and traditional methods used in irrigation district widely respectively. Comparing with water delivery plan compiled using traditional methods, the results illustrate that using this method can get much more reasonable lateral canals water delivery time and homogeneous discharges of upper canal. AGA can adjust the genetic controlling parameters automatically on the basis of values of individual fitness and degree of population dispersion, and get a high precision solution. So it has a higher practical value in irrigation system management.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140017813','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140017813"><span id="translatedtitle">Applying <span class="hlt">Dynamical</span> Systems Theory to <span class="hlt">Optimize</span> Libration Point Orbit Stationkeeping Maneuvers for WIND</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Brown, Jonathan M.; Petersen, Jeremy D.</p> <p>2014-01-01</p> <p>NASA's WIND mission has been operating in a large amplitude Lissajous orbit in the vicinity of the interior libration point of the Sun-Earth/Moon system since 2004. Regular stationkeeping maneuvers are required to maintain the orbit due to the instability around the collinear libration points. Historically these stationkeeping maneuvers have been performed by applying an incremental change in velocity, or (delta)v along the spacecraft-Sun vector as projected into the ecliptic plane. Previous studies have shown that the magnitude of libration point stationkeeping maneuvers can be minimized by applying the (delta)v in the direction of the local stable manifold found using <span class="hlt">dynamical</span> systems theory. This paper presents the analysis of this new maneuver strategy which shows that the magnitude of stationkeeping maneuvers can be decreased by 5 to 25 percent, depending on the location in the orbit where the maneuver is performed. The implementation of the <span class="hlt">optimized</span> maneuver method into operations is discussed and results are presented for the first two <span class="hlt">optimized</span> stationkeeping maneuvers executed by WIND.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/pages/biblio/1227415-optimizing-dynamical-decoupling-protocol-solid-state-electronic-spin-ensembles-diamond','SCIGOV-DOEP'); return false;" href="http://www.osti.gov/pages/biblio/1227415-optimizing-dynamical-decoupling-protocol-solid-state-electronic-spin-ensembles-diamond"><span id="translatedtitle"><span class="hlt">Optimizing</span> a <span class="hlt">dynamical</span> decoupling protocol for solid-state electronic spin ensembles in diamond</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGESBeta</a></p> <p>Farfurnik, D.; Jarmola, A.; Pham, L. M.; Wang, Z. H.; Dobrovitski, V. V.; Walsworth, R. L.; Budker, D.; Bar-Gill, N.</p> <p>2015-08-24</p> <p>In this study, we demonstrate significant improvements of the spin coherence time of a dense ensemble of nitrogen-vacancy (NV) centers in diamond through <span class="hlt">optimized</span> <span class="hlt">dynamical</span> decoupling (DD). Cooling the sample down to 77 K suppresses longitudinal spin relaxation T1 effects and DD microwave pulses are used to increase the transverse coherence time T2 from ~0.7ms up to ~30ms. Furthermore, we extend previous work of single-axis (Carr-Purcell-Meiboom-Gill) DD towards the preservation of arbitrary spin states. Following a theoretical and experimental characterization of pulse and detuning errors, we compare the performance of various DD protocols. We also identify that the <span class="hlt">optimal</span> controlmore » scheme for preserving an arbitrary spin state is a recursive protocol, the concatenated version of the XY8 pulse sequence. The improved spin coherence might have an immediate impact on improvements of the sensitivities of ac magnetometry. Moreover, the protocol can be used on denser diamond samples to increase coherence times up to NV-NV interaction time scales, a major step towards the creation of quantum collective NV spin states.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26319376','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26319376"><span id="translatedtitle">Custom-tailored adsorbers: A molecular <span class="hlt">dynamics</span> study on <span class="hlt">optimal</span> design of ion exchange chromatography material.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lang, Katharina M H; Kittelmann, Jörg; Pilgram, Florian; Osberghaus, Anna; Hubbuch, Jürgen</p> <p>2015-09-25</p> <p>The performance of functionalized materials, e.g., ion exchange resins, depends on multiple resin characteristics, such as type of ligand, ligand density, the pore accessibility for a molecule, and backbone characteristics. Therefore, the screening and identification process for <span class="hlt">optimal</span> resin characteristics for separation is very time and material consuming. Previous studies on the influence of resin characteristics have focused on an experimental approach and to a lesser extent on the mechanistic understanding of the adsorption mechanism. In this in silico study, a previously developed molecular <span class="hlt">dynamics</span> (MD) tool is used, which simulates any given biomolecule on resins with varying ligand densities. We describe a set of simulations and experiments with four proteins and six resins varying in ligand density, and show that simulations and experiments correlate well in a wide range of ligand density. With this new approach simulations can be used as pre-experimental screening for <span class="hlt">optimal</span> adsorber characteristics, reducing the actual number of screening experiments, which results in a faster and more knowledge-based development of custom-tailored adsorbers. PMID:26319376</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1227415','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1227415"><span id="translatedtitle"><span class="hlt">Optimizing</span> a <span class="hlt">dynamical</span> decoupling protocol for solid-state electronic spin ensembles in diamond</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Farfurnik, D.; Jarmola, A.; Pham, L. M.; Wang, Z. H.; Dobrovitski, V. V.; Walsworth, R. L.; Budker, D.; Bar-Gill, N.</p> <p>2015-08-24</p> <p>In this study, we demonstrate significant improvements of the spin coherence time of a dense ensemble of nitrogen-vacancy (NV) centers in diamond through <span class="hlt">optimized</span> <span class="hlt">dynamical</span> decoupling (DD). Cooling the sample down to 77 K suppresses longitudinal spin relaxation T<sub>1</sub> effects and DD microwave pulses are used to increase the transverse coherence time T<sub>2</sub> from ~0.7ms up to ~30ms. Furthermore, we extend previous work of single-axis (Carr-Purcell-Meiboom-Gill) DD towards the preservation of arbitrary spin states. Following a theoretical and experimental characterization of pulse and detuning errors, we compare the performance of various DD protocols. We also identify that the <span class="hlt">optimal</span> control scheme for preserving an arbitrary spin state is a recursive protocol, the concatenated version of the XY8 pulse sequence. The improved spin coherence might have an immediate impact on improvements of the sensitivities of ac magnetometry. Moreover, the protocol can be used on denser diamond samples to increase coherence times up to NV-NV interaction time scales, a major step towards the creation of quantum collective NV spin states.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhRvB..92f0301F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhRvB..92f0301F"><span id="translatedtitle"><span class="hlt">Optimizing</span> a <span class="hlt">dynamical</span> decoupling protocol for solid-state electronic spin ensembles in diamond</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Farfurnik, D.; Jarmola, A.; Pham, L. M.; Wang, Z. H.; Dobrovitski, V. V.; Walsworth, R. L.; Budker, D.; Bar-Gill, N.</p> <p>2015-08-01</p> <p>We demonstrate significant improvements of the spin coherence time of a dense ensemble of nitrogen-vacancy (NV) centers in diamond through <span class="hlt">optimized</span> <span class="hlt">dynamical</span> decoupling (DD). Cooling the sample down to 77 K suppresses longitudinal spin relaxation T1 effects and DD microwave pulses are used to increase the transverse coherence time T2 from ˜0.7 ms up to ˜30 ms . We extend previous work of single-axis (Carr-Purcell-Meiboom-Gill) DD towards the preservation of arbitrary spin states. Following a theoretical and experimental characterization of pulse and detuning errors, we compare the performance of various DD protocols. We identify that the <span class="hlt">optimal</span> control scheme for preserving an arbitrary spin state is a recursive protocol, the concatenated version of the XY8 pulse sequence. The improved spin coherence might have an immediate impact on improvements of the sensitivities of ac magnetometry. Moreover, the protocol can be used on denser diamond samples to increase coherence times up to NV-NV interaction time scales, a major step towards the creation of quantum collective NV spin states.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ChJOL.tmp..136S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ChJOL.tmp..136S"><span id="translatedtitle">Discussion of skill improvement in marine ecosystem <span class="hlt">dynamic</span> models based on parameter <span class="hlt">optimization</span> and skill assessment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shen, Chengcheng; Shi, Honghua; Liu, Yongzhi; Li, Fen; Ding, Dewen</p> <p>2015-12-01</p> <p>Marine ecosystem <span class="hlt">dynamic</span> models (MEDMs) are important tools for the simulation and prediction of marine ecosystems. This article summarizes the methods and strategies used for the improvement and assessment of MEDM skill, and it attempts to establish a technical framework to inspire further ideas concerning MEDM skill improvement. The skill of MEDMs can be improved by parameter <span class="hlt">optimization</span> (PO), which is an important step in model calibration. An efficient approach to solve the problem of PO constrained by MEDMs is the global treatment of both sensitivity analysis and PO. Model validation is an essential step following PO, which validates the efficiency of model calibration by analyzing and estimating the goodness-of-fit of the <span class="hlt">optimized</span> model. Additionally, by focusing on the degree of impact of various factors on model skill, model uncertainty analysis can supply model users with a quantitative assessment of model confidence. Research on MEDMs is ongoing; however, improvement in model skill still lacks global treatments and its assessment is not integrated. Thus, the predictive performance of MEDMs is not strong and model uncertainties lack quantitative descriptions, limiting their application. Therefore, a large number of case studies concerning model skill should be performed to promote the development of a scientific and normative technical framework for the improvement of MEDM skill.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AIPC..718..309M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AIPC..718..309M"><span id="translatedtitle">A Stochastic <span class="hlt">Dynamic</span> Programming Model With Fuzzy Storage States Applied to Reservoir Operation <span class="hlt">Optimization</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mousavi, Seyed Jamshid; Mahdizadeh, Kourosh; Afshar, Abbas</p> <p>2004-08-01</p> <p>Application of stochastic <span class="hlt">dynamic</span> programming (SDP) models to reservoir <span class="hlt">optimization</span> calls for state variables discretization. As an important variable discretization of reservoir storage volume has a pronounced effect on the computational efforts. The error caused by storage volume discretization is examined by considering it as a fuzzy state variable. In this approach, the point-to-point transitions between storage volumes at the beginning and end of each period are replaced by transitions between storage intervals. This is achieved by using fuzzy arithmetic operations with fuzzy numbers. In this approach, instead of aggregating single-valued crisp numbers, the membership functions of fuzzy numbers are combined. Running a simulated model with <span class="hlt">optimal</span> release policies derived from fuzzy and non-fuzzy SDP models shows that a fuzzy SDP with a coarse discretization scheme performs as well as a classical SDP having much finer discretized space. It is believed that this advantage in the fuzzy SDP model is due to the smooth transitions between storage intervals which benefit from soft boundaries.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26552103','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26552103"><span id="translatedtitle">Value Iteration Adaptive <span class="hlt">Dynamic</span> Programming for <span class="hlt">Optimal</span> Control of Discrete-Time Nonlinear Systems.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wei, Qinglai; Liu, Derong; Lin, Hanquan</p> <p>2016-03-01</p> <p>In this paper, a value iteration adaptive <span class="hlt">dynamic</span> programming (ADP) algorithm is developed to solve infinite horizon undiscounted <span class="hlt">optimal</span> control problems for discrete-time nonlinear systems. The present value iteration ADP algorithm permits an arbitrary positive semi-definite function to initialize the algorithm. A novel convergence analysis is developed to guarantee that the iterative value function converges to the <span class="hlt">optimal</span> performance index function. Initialized by different initial functions, it is proven that the iterative value function will be monotonically nonincreasing, monotonically nondecreasing, or nonmonotonic and will converge to the optimum. In this paper, for the first time, the admissibility properties of the iterative control laws are developed for value iteration algorithms. It is emphasized that new termination criteria are established to guarantee the effectiveness of the iterative control laws. Neural networks are used to approximate the iterative value function and compute the iterative control law, respectively, for facilitating the implementation of the iterative ADP algorithm. Finally, two simulation examples are given to illustrate the performance of the present method. PMID:26552103</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JPhA...47b5204C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JPhA...47b5204C"><span id="translatedtitle"><span class="hlt">Optimal</span> control theory for quantum-classical systems: Ehrenfest molecular <span class="hlt">dynamics</span> based on time-dependent density-functional theory</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Castro, A.; Gross, E. K. U.</p> <p>2014-01-01</p> <p>We derive the fundamental equations of an <span class="hlt">optimal</span> control theory for systems containing both quantum electrons and classical ions. The system is modeled with Ehrenfest <span class="hlt">dynamics</span>, a non-adiabatic variant of molecular <span class="hlt">dynamics</span>. The general formulation, that needs the fully correlated many-electron wavefunction, can be simplified by making use of time-dependent density-functional theory. In this case, the <span class="hlt">optimal</span> control equations require some modifications that we will provide. The abstract general formulation is complemented with the simple example of the H_2^+ molecule in the presence of a laser field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/895073','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/895073"><span id="translatedtitle">DAKOTA, a multilevel parallel object-oriented framework for design <span class="hlt">optimization</span>, parameter estimation, uncertainty quantification, and sensitivity analysis:version 4.0 reference manual</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Griffin, Joshua D. (Sandai National Labs, Livermore, CA); Eldred, Michael Scott; Martinez-Canales, Monica L.; Watson, Jean-Paul; Kolda, Tamara Gibson; Adams, Brian M.; Swiler, Laura Painton; Williams, Pamela J.; Hough, Patricia Diane; Gay, David M.; Dunlavy, Daniel M.; Eddy, John P.; Hart, William Eugene; Guinta, Anthony A.; Brown, Shannon L.</p> <p>2006-10-01</p> <p>The DAKOTA (Design Analysis Kit for <span class="hlt">Optimization</span> and Terascale Applications) toolkit provides a flexible and extensible interface between simulation codes and iterative analysis methods. DAKOTA contains algorithms for <span class="hlt">optimization</span> with gradient and nongradient-based methods; uncertainty quantification with sampling, reliability, and stochastic finite element methods; parameter estimation with nonlinear least squares methods; and sensitivity/variance analysis with design of experiments and parameter study methods. These capabilities may be used on their own or as components within advanced strategies such as surrogate-based <span class="hlt">optimization</span>, <span class="hlt">mixed</span> <span class="hlt">integer</span> nonlinear programming, or <span class="hlt">optimization</span> under uncertainty. By employing object-oriented design to implement abstractions of the key components required for iterative systems analyses, the DAKOTA toolkit provides a flexible and extensible problem-solving environment for design and performance analysis of computational models on high performance computers. This report serves as a reference manual for the commands specification for the DAKOTA software, providing input overviews, option descriptions, and example specifications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/991841','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/991841"><span id="translatedtitle">DAKOTA : a multilevel parallel object-oriented framework for design <span class="hlt">optimization</span>, parameter estimation, uncertainty quantification, and sensitivity analysis. Version 5.0, user's reference manual.</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Eldred, Michael Scott; Dalbey, Keith R.; Bohnhoff, William J.; Adams, Brian M.; Swiler, Laura Painton; Hough, Patricia Diane; Gay, David M.; Eddy, John P.; Haskell, Karen H.</p> <p>2010-05-01</p> <p>The DAKOTA (Design Analysis Kit for <span class="hlt">Optimization</span> and Terascale Applications) toolkit provides a flexible and extensible interface between simulation codes and iterative analysis methods. DAKOTA contains algorithms for <span class="hlt">optimization</span> with gradient and nongradient-based methods; uncertainty quantification with sampling, reliability, and stochastic finite element methods; parameter estimation with nonlinear least squares methods; and sensitivity/variance analysis with design of experiments and parameter study methods. These capabilities may be used on their own or as components within advanced strategies such as surrogate-based <span class="hlt">optimization</span>, <span class="hlt">mixed</span> <span class="hlt">integer</span> nonlinear programming, or <span class="hlt">optimization</span> under uncertainty. By employing object-oriented design to implement abstractions of the key components required for iterative systems analyses, the DAKOTA toolkit provides a flexible and extensible problem-solving environment for design and performance analysis of computational models on high performance computers. This report serves as a reference manual for the commands specification for the DAKOTA software, providing input overviews, option descriptions, and example specifications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25530750','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25530750"><span id="translatedtitle">Study of the bus <span class="hlt">dynamic</span> coscheduling <span class="hlt">optimization</span> method under urban rail transit line emergency.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wang, Yun; Yan, Xuedong; Zhou, Yu; Wang, Jiaxi; Chen, Shasha</p> <p>2014-01-01</p> <p>As one of the most important urban commuter transportation modes, urban rail transit (URT) has been acting as a key solution for supporting mobility needs in high-density urban areas. However, in recent years, high frequency of unexpected events has caused serious service disruptions in URT system, greatly harming passenger safety and resulting in severe traffic delays. Therefore, there is an urgent need to study emergency evacuation problem in URT. In this paper, a method of bus <span class="hlt">dynamic</span> coscheduling is proposed and two models are built based on different evacuation destinations including URT stations and surrounding bus parking spots. A <span class="hlt">dynamic</span> coscheduling scheme for buses can be obtained by the models. In the model solution process, a new concept-the equivalent parking spot-is proposed to transform the nonlinear model into an integer linear programming (ILP) problem. A case study is conducted to verify the feasibility of models. Also, sensitivity analysis of two vital factors is carried out to analyze their effects on the total evacuation time. The results reveal that the designed capacity of buses has a negative influence on the total evacuation time, while an increase in the number of passengers has a positive effect. Finally, some significant <span class="hlt">optimizing</span> strategies are proposed. PMID:25530750</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhDT........17S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhDT........17S"><span id="translatedtitle">Multidisciplinary <span class="hlt">optimization</span> for the design and control of uncertain <span class="hlt">dynamical</span> systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sridharan, Srikanth</p> <p></p> <p>This dissertation considers an integrated approach to system design and controller design based on analyzing limits of system performance. Historically, plant design methodologies have not incorporated control relevant considerations. Such an approach could result in a system that might not meet its specifications (or one that requires a complex control architecture to do so). System and controller designers often go through several iterations in order to converge to an acceptable plant and controller design. The focus of this dissertation is on the design and control an air-breathing hypersonic vehicle using such an integrated system-control design framework. The goal is to reduce the number of system-control design iterations (by explicitly incorporate control considerations in the system design process), as well as to influence the guidance/trajectory specifications for the system. Due to the high computational costs associated with obtaining a <span class="hlt">dynamic</span> model for each plant configuration considered, approximations to the system <span class="hlt">dynamics</span> are used in the control design process. By formulating the control design problem using bilinear and polynomial matrix inequalities, several common control and system design constraints can be simultaneously incorporated into a vehicle design <span class="hlt">optimization</span>. Several design problems are examined to illustrate the effectiveness of this approach (and to compare the computational burden of this methodology against more traditional approaches).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JAGeo...8..265M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JAGeo...8..265M"><span id="translatedtitle"><span class="hlt">Optimal</span> GPS/accelerometer integration algorithm for monitoring the vertical structural <span class="hlt">dynamics</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Meng, Xiaolin; Wang, Jian; Han, Houzeng</p> <p>2014-11-01</p> <p>The vertical structural <span class="hlt">dynamics</span> is a crucial factor for structural health monitoring (SHM) of civil structures such as high-rise buildings, suspension bridges and towers. This paper presents an <span class="hlt">optimal</span> GPS/accelerometer integration algorithm for an automated multi-sensor monitoring system. The closed loop feedback algorithm for integrating the vertical GPS and accelerometer measurements is proposed based on a 5 state extended KALMAN filter (EKF) and then the narrow moving window Fast Fourier Transform (FFT) analysis is applied to extract structural <span class="hlt">dynamics</span>. A civil structural vibration is simulated and the analysed result shows the proposed algorithm can effectively integrate the online vertical measurements produced by GPS and accelerometer. Furthermore, the accelerometer bias and scale factor can also be estimated which is impossible with traditional integration algorithms. Further analysis shows the vibration frequencies detected in GPS or accelerometer are all included in the integrated vertical defection time series and the accelerometer can effectively compensate the short-term GPS outages with high quality. Finally, the data set collected with a time synchronised and integrated GPS/accelerometer monitoring system installed on the Nottingham Wilford Bridge when excited by 15 people jumping together at its mid-span are utilised to verify the effectiveness of this proposed algorithm. Its implementations are satisfactory and the detected vibration frequencies are 1.720 Hz, 1.870 Hz, 2.104 Hz, 2.905 Hz and also 10.050 Hz, which is not found in GPS or accelerometer only measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JNS....24..245P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JNS....24..245P"><span id="translatedtitle">An <span class="hlt">Optimal</span> Model Identification for Oscillatory <span class="hlt">Dynamics</span> with a Stable Limit Cycle</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Protas, Bartosz; Noack, Bernd R.; Morzyński, Marek</p> <p>2014-04-01</p> <p>We propose a general framework for the parameter-free identification of a class of <span class="hlt">dynamical</span> systems. Here, the propagator is approximated in terms of an arbitrary function of the state, in contrast to a polynomial or Galerkin expansion used in traditional approaches. The proposed formulation relies on variational data assimilation using measurement data combined with assumptions on the smoothness of the propagator. This approach is illustrated using a generalized <span class="hlt">dynamic</span> model describing oscillatory transients from an unstable fixed point to a stable limit cycle and arising in nonlinear stability analysis as an example. This 3-state model comprises an evolution equation for the dominant oscillation and an algebraic manifold for the low- and high-frequency components in an autonomous descriptor system. The proposed <span class="hlt">optimal</span> model identification technique employs mode amplitudes of the transient vortex shedding in a cylinder wake flow as example measurements. The reconstruction obtained with our technique features distinct and systematic improvements over the well-known mean-field (Landau) model of the Hopf bifurcation. The computational aspect of the identification method is thoroughly validated showing that good reconstructions can also be obtained in the absence of accurate initial approximations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JSV...333.4653C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JSV...333.4653C"><span id="translatedtitle">On the <span class="hlt">dynamics</span> and <span class="hlt">optimization</span> of a non-smooth bistable oscillator - Application to energy harvesting</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cohen, Nadav; Bucher, Izhak</p> <p>2014-09-01</p> <p>Bistable nonlinear oscillators can transform slow sinusoidal excitations into higher frequency periodic or quasi-periodic oscillations. This behaviour can be exploited to efficiently convert mechanical oscillations into electrical power, but being nonlinear, their <span class="hlt">dynamical</span> behaviour is relatively complicated. In order to better understand the <span class="hlt">dynamics</span> of bistable oscillators, an approximate bilinear analytical model, which is valid for narrow potential barriers, is developed. This model is expanded to the case of wider potential with experimental verification. Indeed, the model is verified by numerical simulations and a suitable Poincaré section that the analytical model captures most of bifurcations for large amplitude vibrations and can be used to <span class="hlt">optimize</span> the harvested power of such devices. The method of Shaw and Holmes [1] is enhanced by exploiting symmetry to obtain closed form expressions of the Poincaré section and mapping. The approximate non-smooth model proves useful in the study of orbital stability, large amplitude oscillations and in explaining most of the period doubling and symmetry breaking bifurcations arising when such an oscillator is subjected to sinusoidal excitation. The proposed model is successfully verified through analytical numerical analysis and some experimental results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4235110','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4235110"><span id="translatedtitle">Study of the Bus <span class="hlt">Dynamic</span> Coscheduling <span class="hlt">Optimization</span> Method under Urban Rail Transit Line Emergency</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Yan, Xuedong; Wang, Jiaxi; Chen, Shasha</p> <p>2014-01-01</p> <p>As one of the most important urban commuter transportation modes, urban rail transit (URT) has been acting as a key solution for supporting mobility needs in high-density urban areas. However, in recent years, high frequency of unexpected events has caused serious service disruptions in URT system, greatly harming passenger safety and resulting in severe traffic delays. Therefore, there is an urgent need to study emergency evacuation problem in URT. In this paper, a method of bus <span class="hlt">dynamic</span> coscheduling is proposed and two models are built based on different evacuation destinations including URT stations and surrounding bus parking spots. A <span class="hlt">dynamic</span> coscheduling scheme for buses can be obtained by the models. In the model solution process, a new concept—the equivalent parking spot—is proposed to transform the nonlinear model into an integer linear programming (ILP) problem. A case study is conducted to verify the feasibility of models. Also, sensitivity analysis of two vital factors is carried out to analyze their effects on the total evacuation time. The results reveal that the designed capacity of buses has a negative influence on the total evacuation time, while an increase in the number of passengers has a positive effect. Finally, some significant <span class="hlt">optimizing</span> strategies are proposed. PMID:25530750</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26011881','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26011881"><span id="translatedtitle">High <span class="hlt">dynamic</span> range image compression by <span class="hlt">optimizing</span> tone mapped image quality index.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ma, Kede; Yeganeh, Hojatollah; Zeng, Kai; Wang, Zhou</p> <p>2015-10-01</p> <p>Tone mapping operators (TMOs) aim to compress high <span class="hlt">dynamic</span> range (HDR) images to low <span class="hlt">dynamic</span> range (LDR) ones so as to visualize HDR images on standard displays. Most existing TMOs were demonstrated on specific examples without being thoroughly evaluated using well-designed and subject-validated image quality assessment models. A recently proposed tone mapped image quality index (TMQI) made one of the first attempts on objective quality assessment of tone mapped images. Here, we propose a substantially different approach to design TMO. Instead of using any predefined systematic computational structure for tone mapping (such as analytic image transformations and/or explicit contrast/edge enhancement), we directly navigate in the space of all images, searching for the image that <span class="hlt">optimizes</span> an improved TMQI. In particular, we first improve the two building blocks in TMQI—structural fidelity and statistical naturalness components—leading to a TMQI-II metric. We then propose an iterative algorithm that alternatively improves the structural fidelity and statistical naturalness of the resulting image. Numerical and subjective experiments demonstrate that the proposed algorithm consistently produces better quality tone mapped images even when the initial images of the iteration are created by the most competitive TMOs. Meanwhile, these results also validate the superiority of TMQI-II over TMQI. PMID:26011881</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/374523','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/374523"><span id="translatedtitle">Fluid <span class="hlt">dynamic</span> <span class="hlt">optimization</span> of SCR plants by modeling demonstrated by the SCR plant Logan Generating Plant</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hauenstein, K.; Herr, W.; Sigling, R.</p> <p>1996-01-01</p> <p>The SCR process for the reduction of nitrogen oxides has proven itself in practical application in many fossil-fired power stations. The concept of integrating a high-dust SCR plant between the boiler and air preheater has often been hampered by structural constraints. As a result of the limited space available, the plant`s ducting will have in most cases a high degree of complexity. In order to achieve efficient SCR plant functioning, however, the flow conditions have to be analyzed in detail and to be <span class="hlt">optimized</span>. The goal is to obtain uniform flow distribution upstream of the catalysts and a homogeneous distribution of the reducing agent ammonia, while incurring as small a pressure drop as possible. To this end, fluid <span class="hlt">dynamic</span> measures are implemented such as the installation of guide vanes and static mixing systems. This paper describes the procedure used to meet the requirements mentioned above. It enables the changes and modifications to be developed efficiently in terms of time and cost. Experience shows that the results obtained can indeed be transferred to and confirmed in a full-scale plant. The fluid <span class="hlt">dynamic</span> solutions derived by modeling and the adaptation of a static mixer to the geometry of the flue gas ducting are demonstrated using the example of the SCR plant at the Logan Generating Plant operated by US Generating Company. The results of the measurements are presented to illustrate the mechanisms of the modifications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.H41J..01C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.H41J..01C"><span id="translatedtitle"><span class="hlt">Dynamic</span> emulation modelling for the <span class="hlt">optimal</span> operation of water systems: an overview</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Castelletti, A.; Galelli, S.; Giuliani, M.</p> <p>2014-12-01</p> <p>Despite sustained increase in computing power over recent decades, computational limitations remain a major barrier to the effective and systematic use of large-scale, process-based simulation models in rational environmental decision-making. Whereas complex models may provide clear advantages when the goal of the modelling exercise is to enhance our understanding of the natural processes, they introduce problems of model identifiability caused by over-parameterization and suffer from high computational burden when used in management and planning problems. As a result, increasing attention is now being devoted to emulation modelling (or model reduction) as a way of overcoming these limitations. An emulation model, or emulator, is a low-order approximation of the process-based model that can be substituted for it in order to solve high resource-demanding problems. In this talk, an overview of emulation modelling within the context of the <span class="hlt">optimal</span> operation of water systems will be provided. Particular emphasis will be given to <span class="hlt">Dynamic</span> Emulation Modelling (DEMo), a special type of model complexity reduction in which the <span class="hlt">dynamic</span> nature of the original process-based model is preserved, with consequent advantages in a wide range of problems, particularly feedback control problems. This will be contrasted with traditional non-<span class="hlt">dynamic</span> emulators (e.g. response surface and surrogate models) that have been studied extensively in recent years and are mainly used for planning purposes. A number of real world numerical experiences will be used to support the discussion ranging from multi-outlet water quality control in water reservoir through erosion/sedimentation rebalancing in the operation of run-off-river power plants to salinity control in lake and reservoirs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24951713','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24951713"><span id="translatedtitle">A <span class="hlt">dynamic</span> multiarmed bandit-gene expression programming hyper-heuristic for combinatorial <span class="hlt">optimization</span> problems.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sabar, Nasser R; Ayob, Masri; Kendall, Graham; Qu, Rong</p> <p>2015-02-01</p> <p>Hyper-heuristics are search methodologies that aim to provide high-quality solutions across a wide variety of problem domains, rather than developing tailor-made methodologies for each problem instance/domain. A traditional hyper-heuristic framework has two levels, namely, the high level strategy (heuristic selection mechanism and the acceptance criterion) and low level heuristics (a set of problem specific heuristics). Due to the different landscape structures of different problem instances, the high level strategy plays an important role in the design of a hyper-heuristic framework. In this paper, we propose a new high level strategy for a hyper-heuristic framework. The proposed high-level strategy utilizes a <span class="hlt">dynamic</span> multiarmed bandit-extreme value-based reward as an online heuristic selection mechanism to select the appropriate heuristic to be applied at each iteration. In addition, we propose a gene expression programming framework to automatically generate the acceptance criterion for each problem instance, instead of using human-designed criteria. Two well-known, and very different, combinatorial <span class="hlt">optimization</span> problems, one static (exam timetabling) and one <span class="hlt">dynamic</span> (<span class="hlt">dynamic</span> vehicle routing) are used to demonstrate the generality of the proposed framework. Compared with state-of-the-art hyper-heuristics and other bespoke methods, empirical results demonstrate that the proposed framework is able to generalize well across both domains. We obtain competitive, if not better results, when compared to the best known results obtained from other methods that have been presented in the scientific literature. We also compare our approach against the recently released hyper-heuristic competition test suite. We again demonstrate the generality of our approach when we compare against other methods that have utilized the same six benchmark datasets from this test suite. PMID:24951713</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25791283','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25791283"><span id="translatedtitle">The role of residence times in two-patch dengue transmission <span class="hlt">dynamics</span> and <span class="hlt">optimal</span> strategies.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lee, Sunmi; Castillo-Chavez, Carlos</p> <p>2015-06-01</p> <p>The reemergence and geographical dispersal of vector-borne diseases challenge global health experts around the world and in particular, dengue poses increasing difficulties in the Americas, due in part to explosive urban and semi-urban growth, increases of within and between region mobility, the absence of a vaccine, and the limited resources available for public health services. In this work, a simple deterministic two-patch model is introduced to assess the impact of dengue transmission <span class="hlt">dynamics</span> in heterogeneous environments. The two-patch system models the movement (e.g. urban versus rural areas residence times) of individuals between and within patches/environments using residence-time matrices with entries that budget within and between host patch relative residence times, under the assumption that only the human budgets their residence time across regions. Three scenarios are considered: (i) resident hosts in Patch i visit patch j, where i≠j but not the other way around, a scenario referred to as unidirectional motion; (ii) symmetric bi-directional motion; and (iii) asymmetric bi-directional motion. <span class="hlt">Optimal</span> control theory is used to identify and evaluate patch-specific control measures aimed at reducing dengue prevalence in humans and vectors at a minimal cost. <span class="hlt">Optimal</span> policies are computed under different residence-matrix configurations mentioned above as well as transmissibility scenarios characterized by the magnitude of the basic reproduction number. <span class="hlt">Optimal</span> patch-specific polices can ameliorate the impact of epidemic outbreaks substantially when the basic reproduction number is moderate. The final patch-specific epidemic size variation increases as the residence time matrix moves away from the symmetric case (asymmetry). As expected, the patch where individuals spend most of their time or in the patch where transmissibility is higher tend to support larger patch-specific final epidemic sizes. Hence, focusing on intervention that target areas where individuals spend "most" time or where transmissibility is higher turn out to be <span class="hlt">optimal</span>. Therefore, reducing traffic is likely to take a host-vector system into the world of manageable outbreaks. PMID:25791283</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PMB....58.7391K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PMB....58.7391K"><span id="translatedtitle"><span class="hlt">Dynamic</span> whole-body PET parametric imaging: I. Concept, acquisition protocol <span class="hlt">optimization</span> and clinical application</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Karakatsanis, Nicolas A.; Lodge, Martin A.; Tahari, Abdel K.; Zhou, Y.; Wahl, Richard L.; Rahmim, Arman</p> <p>2013-10-01</p> <p>Static whole-body PET/CT, employing the standardized uptake value (SUV), is considered the standard clinical approach to diagnosis and treatment response monitoring for a wide range of oncologic malignancies. Alternative PET protocols involving <span class="hlt">dynamic</span> acquisition of temporal images have been implemented in the research setting, allowing quantification of tracer <span class="hlt">dynamics</span>, an important capability for tumor characterization and treatment response monitoring. Nonetheless, <span class="hlt">dynamic</span> protocols have been confined to single-bed-coverage limiting the axial field-of-view to ˜15-20 cm, and have not been translated to the routine clinical context of whole-body PET imaging for the inspection of disseminated disease. Here, we pursue a transition to <span class="hlt">dynamic</span> whole-body PET parametric imaging, by presenting, within a unified framework, clinically feasible multi-bed <span class="hlt">dynamic</span> PET acquisition protocols and parametric imaging methods. We investigate solutions to address the challenges of: (i) long acquisitions, (ii) small number of <span class="hlt">dynamic</span> frames per bed, and (iii) non-invasive quantification of kinetics in the plasma. In the present study, a novel <span class="hlt">dynamic</span> (4D) whole-body PET acquisition protocol of ˜45 min total length is presented, composed of (i) an initial 6 min <span class="hlt">dynamic</span> PET scan (24 frames) over the heart, followed by (ii) a sequence of multi-pass multi-bed PET scans (six passes × seven bed positions, each scanned for 45 s). Standard Patlak linear graphical analysis modeling was employed, coupled with image-derived plasma input function measurements. Ordinary least squares Patlak estimation was used as the baseline regression method to quantify the physiological parameters of tracer uptake rate Ki and total blood distribution volume V on an individual voxel basis. Extensive Monte Carlo simulation studies, using a wide set of published kinetic FDG parameters and GATE and XCAT platforms, were conducted to <span class="hlt">optimize</span> the acquisition protocol from a range of ten different clinically acceptable sampling schedules examined. The framework was also applied to six FDG PET patient studies, demonstrating clinical feasibility. Both simulated and clinical results indicated enhanced contrast-to-noise ratios (CNRs) for Ki images in tumor regions with notable background FDG concentration, such as the liver, where SUV performed relatively poorly. Overall, the proposed framework enables enhanced quantification of physiological parameters across the whole body. In addition, the total acquisition length can be reduced from 45 to ˜35 min and still achieve improved or equivalent CNR compared to SUV, provided the true Ki contrast is sufficiently high. In the follow-up companion paper, a set of advanced linear regression schemes is presented to particularly address the presence of noise, and attempt to achieve a better trade-off between the mean-squared error and the CNR metrics, resulting in enhanced task-based imaging.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3941007','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3941007"><span id="translatedtitle"><span class="hlt">Dynamic</span> whole body PET parametric imaging: I. Concept, acquisition protocol <span class="hlt">optimization</span> and clinical application</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Karakatsanis, Nicolas A.; Lodge, Martin A.; Tahari, Abdel K.; Zhou, Y.; Wahl, Richard L.; Rahmim, Arman</p> <p>2013-01-01</p> <p>Static whole body PET/CT, employing the standardized uptake value (SUV), is considered the standard clinical approach to diagnosis and treatment response monitoring for a wide range of oncologic malignancies. Alternative PET protocols involving <span class="hlt">dynamic</span> acquisition of temporal images have been implemented in the research setting, allowing quantification of tracer <span class="hlt">dynamics</span>, an important capability for tumor characterization and treatment response monitoring. Nonetheless, <span class="hlt">dynamic</span> protocols have been confined to single bed-coverage limiting the axial field-of-view to ~1520 cm, and have not been translated to the routine clinical context of whole-body PET imaging for the inspection of disseminated disease. Here, we pursue a transition to <span class="hlt">dynamic</span> whole body PET parametric imaging, by presenting, within a unified framework, clinically feasible multi-bed <span class="hlt">dynamic</span> PET acquisition protocols and parametric imaging methods. We investigate solutions to address the challenges of: (i) long acquisitions, (ii) small number of <span class="hlt">dynamic</span> frames per bed, and (iii) non-invasive quantification of kinetics in the plasma. In the present study, a novel <span class="hlt">dynamic</span> (4D) whole body PET acquisition protocol of ~45min total length is presented, composed of (i) an initial 6-min <span class="hlt">dynamic</span> PET scan (24 frames) over the heart, followed by (ii) a sequence of multi-pass multi-bed PET scans (6 passes x 7 bed positions, each scanned for 45sec). Standard Patlak linear graphical analysis modeling was employed, coupled with image-derived plasma input function measurements. Ordinary least squares (OLS) Patlak estimation was used as the baseline regression method to quantify the physiological parameters of tracer uptake rate Ki and total blood distribution volume V on an individual voxel basis. Extensive Monte Carlo simulation studies, using a wide set of published kinetic FDG parameters and GATE and XCAT platforms, were conducted to <span class="hlt">optimize</span> the acquisition protocol from a range of 10 different clinically acceptable sampling schedules examined. The framework was also applied to six FDG PET patient studies, demonstrating clinical feasibility. Both simulated and clinical results indicated enhanced contrast-to-noise ratios (CNRs) for Ki images in tumor regions with notable background FDG concentration, such as the liver, where SUV performed relatively poorly. Overall, the proposed framework enables enhanced quantification of physiological parameters across the whole-body. In addition, the total acquisition length can be reduced from 45min to ~35min and still achieve improved or equivalent CNR compared to SUV, provided the true Ki contrast is sufficiently high. In the follow-up companion paper, a set of advanced linear regression schemes is presented to particularly address the presence of noise, and attempt to achieve a better trade-off between the mean-squared error (MSE) and the CNR metrics, resulting in enhanced task-based imaging. PMID:24080962</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22472538','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22472538"><span id="translatedtitle"><span class="hlt">Optimization</span> of municipal solid waste collection and transportation routes</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Das, Swapan Bhattacharyya, Bidyut Kr.</p> <p>2015-09-15</p> <p>Graphical abstract: Display Omitted - Highlights: • Profitable integrated solid waste management system. • <span class="hlt">Optimal</span> municipal waste collection scheme between the sources and waste collection centres. • <span class="hlt">Optimal</span> path calculation between waste collection centres and transfer stations. • <span class="hlt">Optimal</span> waste routing between the transfer stations and processing plants. - Abstract: <span class="hlt">Optimization</span> of municipal solid waste (MSW) collection and transportation through source separation becomes one of the major concerns in the MSW management system design, due to the fact that the existing MSW management systems suffer by the high collection and transportation cost. Generally, in a city different waste sources scatter throughout the city in heterogeneous way that increase waste collection and transportation cost in the waste management system. Therefore, a shortest waste collection and transportation strategy can effectively reduce waste collection and transportation cost. In this paper, we propose an <span class="hlt">optimal</span> MSW collection and transportation scheme that focus on the problem of minimizing the length of each waste collection and transportation route. We first formulize the MSW collection and transportation problem into a <span class="hlt">mixed</span> <span class="hlt">integer</span> program. Moreover, we propose a heuristic solution for the waste collection and transportation problem that can provide an <span class="hlt">optimal</span> way for waste collection and transportation. Extensive simulations and real testbed results show that the proposed solution can significantly improve the MSW performance. Results show that the proposed scheme is able to reduce more than 30% of the total waste collection path length.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013WRR....49.3180T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013WRR....49.3180T"><span id="translatedtitle">Fuzzy multiobjective models for <span class="hlt">optimal</span> operation of a hydropower system</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Teegavarapu, Ramesh S. V.; Ferreira, Andr R.; Simonovic, Slobodan P.</p> <p>2013-06-01</p> <p><span class="hlt">Optimal</span> operation models for a hydropower system using new fuzzy multiobjective mathematical programming models are developed and evaluated in this study. The models use (i) <span class="hlt">mixed</span> <span class="hlt">integer</span> nonlinear programming (MINLP) with binary variables and (ii) integrate a new turbine unit commitment formulation along with water quality constraints used for evaluation of reservoir downstream impairment. Reardon method used in solution of genetic algorithm <span class="hlt">optimization</span> problems forms the basis for development of a new fuzzy multiobjective hydropower system <span class="hlt">optimization</span> model with creation of Reardon type fuzzy membership functions. The models are applied to a real-life hydropower reservoir system in Brazil. Genetic Algorithms (GAs) are used to (i) solve the <span class="hlt">optimization</span> formulations to avoid computational intractability and combinatorial problems associated with binary variables in unit commitment, (ii) efficiently address Reardon method formulations, and (iii) deal with local <span class="hlt">optimal</span> solutions obtained from the use of traditional gradient-based solvers. Decision maker's preferences are incorporated within fuzzy mathematical programming formulations to obtain compromise operating rules for a multiobjective reservoir operation problem dominated by conflicting goals of energy production, water quality and conservation releases. Results provide insight into compromise operation rules obtained using the new Reardon fuzzy multiobjective <span class="hlt">optimization</span> framework and confirm its applicability to a variety of multiobjective water resources problems.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1994PrOce..34....1R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1994PrOce..34....1R"><span id="translatedtitle">A <span class="hlt">dynamic</span> <span class="hlt">optimization</span> model of the diel vertical distribution of a pelagic planktivorous fish</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rosland, Rune; Giske, Jarl</p> <p></p> <p>A stochastic <span class="hlt">dynamic</span> <span class="hlt">optimization</span> model for the diel depth distribution of juveniles and adults of the mesopelagic planktivore Maurolicus muelleri (Gmelin) is developed and used for a winter situation. Observations from Masfjorden, western Norway, reveal differences in vertical distribution, growth and mortality between juveniles and adults in January. Juveniles stay within the upper 100m with high feeding rates, while adults stay within the 100-150m zone with very low feeding rates during the diel cycle. The difference in depth profitability is assumed to be caused by age-dependent processes, and are calculated from a mechanistic model for visual feeding. The environment is described as a set of habitats represented by discrete depth intervals along the vertical axis, differing with respect to light intensity, food abundance, predation risk and temperature. The short time interval (24h) allows fitness to be linearly related to growth (feeding), assuming that growth increases the future reproductive output of the fish. <span class="hlt">Optimal</span> depth position is calculated from balancing feeding opportunity against mortality risk, where the fitness reward gained by feeding is weighted against the danger of being killed by a predator. A basic run is established, and the model is validated by comparing predictions and observations. The sensitivity for different parameter values is also tested. The modelled vertical distributions and feeding patterns of juvenile and adult fish correspond well with the observations, and the assumption of age differences in mortality-feeding trade-offs seems adequate to explain the different depth profitability of the two age groups. The results indicate a preference for crepuscular feeding activity of the juveniles, and the vertical distribution of zooplankton seems to be the most important environmental factor regulating the adult depth position during the winter months in Masfjorden.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4142329','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4142329"><span id="translatedtitle"><span class="hlt">Optimal</span> Control Strategy Design Based on <span class="hlt">Dynamic</span> Programming for a Dual-Motor Coupling-Propulsion System</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Zhang, Shuo; Zhang, Chengning; Han, Guangwei; Wang, Qinghui</p> <p>2014-01-01</p> <p>A dual-motor coupling-propulsion electric bus (DMCPEB) is modeled, and its <span class="hlt">optimal</span> control strategy is studied in this paper. The necessary <span class="hlt">dynamic</span> features of energy loss for subsystems is modeled. <span class="hlt">Dynamic</span> programming (DP) technique is applied to find the <span class="hlt">optimal</span> control strategy including upshift threshold, downshift threshold, and power split ratio between the main motor and auxiliary motor. Improved control rules are extracted from the DP-based control solution, forming near-<span class="hlt">optimal</span> control strategies. Simulation results demonstrate that a significant improvement in reducing energy loss due to the dual-motor coupling-propulsion system (DMCPS) running is realized without increasing the frequency of the mode switch. PMID:25540814</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080043872','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080043872"><span id="translatedtitle">Using Maximal Isometric Force to Determine the <span class="hlt">Optimal</span> Load for Measuring <span class="hlt">Dynamic</span> Muscle Power</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Spiering, Barry A.; Lee, Stuart M. C.; Mulavara, Ajitkumar P.; Bentley, Jason R.; Nash, Roxanne E.; Sinka, Joseph; Bloomberg, Jacob J.</p> <p>2009-01-01</p> <p>Maximal power output occurs when subjects perform ballistic exercises using loads of 30-50% of one-repetition maximum (1-RM). However, performing 1-RM testing prior to power measurement requires considerable time, especially when testing involves multiple exercises. Maximal isometric force (MIF), which requires substantially less time to measure than 1-RM, might be an acceptable alternative for determining the <span class="hlt">optimal</span> load for power testing. PURPOSE: To determine the <span class="hlt">optimal</span> load based on MIF for maximizing <span class="hlt">dynamic</span> power output during leg press and bench press exercises. METHODS: Twenty healthy volunteers (12 men and 8 women; mean +/- SD age: 31+/-6 y; body mass: 72 +/- 15 kg) performed isometric leg press and bench press movements, during which MIF was measured using force plates. Subsequently, subjects performed ballistic leg press and bench press exercises using loads corresponding to 20%, 30%, 40%, 50%, and 60% of MIF presented in randomized order. Maximal instantaneous power was calculated during the ballistic exercise tests using force plates and position transducers. Repeated-measures ANOVA and Fisher LSD post hoc tests were used to determine the load(s) that elicited maximal power output. RESULTS: For the leg press power test, six subjects were unable to be tested at 20% and 30% MIF because these loads were less than the lightest possible load (i.e., the weight of the unloaded leg press sled assembly [31.4 kg]). For the bench press power test, five subjects were unable to be tested at 20% MIF because these loads were less than the weight of the unloaded aluminum bar (i.e., 11.4 kg). Therefore, these loads were excluded from analysis. A trend (p = 0.07) for a main effect of load existed for the leg press exercise, indicating that the 40% MIF load tended to elicit greater power output than the 60% MIF load (effect size = 0.38). A significant (p . 0.05) main effect of load existed for the bench press exercise; post hoc analysis indicated that the effect of load on power output was: 30% > 40% > 50% = 60%. CONCLUSION: Loads of 40% and 30% of MIF elicit maximal power output during <span class="hlt">dynamic</span> leg presses and bench presses, respectively. These findings are similar to those obtained when loading is based on 1-RM.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..1512639B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..1512639B"><span id="translatedtitle">Combined mid- and short-term <span class="hlt">optimization</span> of multireservoir systems via <span class="hlt">dynamic</span> programming with function approximators</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bottacin-Busolin, Andrea; Wörman, Anders; Zmijewski, Nicholas</p> <p>2013-04-01</p> <p>A main challenge for the planning and management of water resources is the development of strategies for regulation of multireservoir systems under a complex stochastic environment. The sequential decision problem involving the release of water from multiple reservoirs depends on the stochastic variability of the hydrologic inflows over a spectrum of time scales. An important distinction is made between short-term and mid-term planning: the first is associated with regulation on the hourly scale within the one-week time horizon, whilst the second is associated with the weekly scale within the one-year horizon. Although a variety of <span class="hlt">optimization</span> methods have been suggested, the achievement of a global optimum in the operation of large-scale systems is hindered by their high dimensional state space and by the stochastic nature of the hydrologic inflows. In this work, operational plans for multireservoir systems are derived via an approximate <span class="hlt">dynamic</span> programming approach using a policy iteration algorithm. The algorithm is based on an off-line learning process in which policies are evaluated for a number of stochastic inflow scenarios by constructing approximations of their value functions, and the resulting value functions are used iteratively to design new, improved policies. In the mid-term planning phase, inflow scenarios are generated with a periodic autoregressive model that is calibrated against historical inflow data, and the policy iteration algorithm leads to a cyclostationary operating policy. In the short-term planning phase, the mid-term value function is used to calculate the value of a policy at the end of the short-term operating horizon, and synthetic inflow scenarios are generated by perturbing streamflow forecasts with Gaussian noise, following Zhao et al. (Water Resour. Res., 48, W01540, 2012). The variance of the noise is assumed to increase linearly over time and converges to the local variance of the historical time series. A case study is presented of a multi-reservoir system in the river Dalälven, Sweden, where the impact of forecast uncertainty and the performance of the proposed stochastic <span class="hlt">optimization</span> model is evaluated using observed time series and synthetic inflow forecasts. The resulting electricity production is compared with the <span class="hlt">optimal</span> production in case of perfect a priori information and the expected production from the application of a myopic operating policy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22131248','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22131248"><span id="translatedtitle">HybridArc: A novel radiation therapy technique combining <span class="hlt">optimized</span> <span class="hlt">dynamic</span> arcs and intensity modulation</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Robar, James L.; Thomas, Christopher</p> <p>2012-01-01</p> <p>This investigation focuses on possible dosimetric and efficiency advantages of HybridArc-a novel treatment planning approach combining <span class="hlt">optimized</span> <span class="hlt">dynamic</span> arcs with intensity-modulated radiation therapy (IMRT) beams. Application of this technique to two disparate sites, complex cranial tumors, and prostate was examined. HybridArc plans were compared with either <span class="hlt">dynamic</span> conformal arc (DCA) or IMRT plans to determine whether HybridArc offers a synergy through combination of these 2 techniques. Plans were compared with regard to target volume dose conformity, target volume dose homogeneity, sparing of proximal organs at risk, normal tissue sparing, and monitor unit (MU) efficiency. For cranial cases, HybridArc produced significantly improved dose conformity compared with both DCA and IMRT but did not improve sparing of the brainstem or optic chiasm. For prostate cases, conformity was improved compared with DCA but not IMRT. Compared with IMRT, the dose homogeneity in the planning target volume was improved, and the maximum doses received by the bladder and rectum were reduced. Both arc-based techniques distribute peripheral dose over larger volumes of normal tissue compared with IMRT, whereas HybridArc involved slightly greater volumes of normal tissues compared with DCA. Compared with IMRT, cranial cases required 38% more MUs, whereas for prostate cases, MUs were reduced by 7%. For cranial cases, HybridArc improves dose conformity to the target. For prostate cases, dose conformity and homogeneity are improved compared with DCA and IMRT, respectively. Compared with IMRT, whether required MUs increase or decrease with HybridArc was site-dependent.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015OptCo.356..256B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015OptCo.356..256B"><span id="translatedtitle"><span class="hlt">Optimized</span> swimmer tracking system by a <span class="hlt">dynamic</span> fusion of correlation and color histogram techniques</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Benarab, D.; Napoléon, T.; Alfalou, A.; Verney, A.; Hellard, P.</p> <p>2015-12-01</p> <p>To design a robust swimmer tracking system, we took into account two well-known tracking techniques: the nonlinear joint transform correlation (NL-JTC) and the color histogram. The two techniques perform comparably well, yet they both have substantial limitations. Interestingly, they also seem to show some complementarity. The correlation technique yields accurate detection but is sensitive to rotation, scale and contour deformation, whereas the color histogram technique is robust for rotation and contour deformation but shows low accuracy and is highly sensitive to luminosity and confusing background colors. These observations suggested the possibility of a <span class="hlt">dynamic</span> fusion of the correlation plane and the color scores map. Before this fusion, two steps are required. First is the extraction of a sub-plane of correlation that describes the similarity between the reference and target images. This sub-plane has the same size as the color scores map but they have different interval values. Thus, the second step is required which is the normalization of the planes in the same interval so they can be fused. In order to determine the benefits of this fusion technique, first, we tested it on a synthetic image containing different forms with different colors. We thus were able to <span class="hlt">optimize</span> the correlation plane and color histogram techniques before applying our fusion technique to real videos of swimmers in international competitions. Last, a comparative study of the <span class="hlt">dynamic</span> fusion technique and the two classical techniques was carried out to demonstrate the efficacy of the proposed technique. The criteria of comparison were the tracking percentage, the peak to correlation energy (PCE), which evaluated the sharpness of the peak (accuracy), and the local standard deviation (Local-STD), which assessed the noise in the planes (robustness).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26994784','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26994784"><span id="translatedtitle">Femoral strain during walking predicted with muscle forces from static and <span class="hlt">dynamic</span> <span class="hlt">optimization</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Edwards, W Brent; Miller, Ross H; Derrick, Timothy R</p> <p>2016-05-01</p> <p>Mechanical strain plays an important role in skeletal health, and the ability to accurately and noninvasively quantify bone strain in vivo may be used to develop preventive measures that improve bone quality and decrease fracture risk. A non-invasive estimation of bone strain requires combined musculoskeletal - finite element modeling, for which the applied muscle forces are usually obtained from static <span class="hlt">optimization</span> (SO) methods. In this study, we compared finite element predicted femoral strains in walking using muscle forces obtained from SO to those obtained from forward <span class="hlt">dynamics</span> (FD) simulation. The general trends in strain distributions were similar between FD and SO derived conditions and both agreed well with previously reported in vivo strain gage measurements. On the other hand, differences in peak maximum (εmax) and minimum (εmin) principal strain magnitudes were as high as 32% between FD (εmax/εmin=945/-1271με) and SO (εmax/εmin=752/-859με). These large differences in strain magnitudes were observed during the first half of stance, where SO predicted lower gluteal muscle forces and virtually no co-contraction of the hip adductors compared to FD. The importance of these results will likely depend on the purpose/application of the modeling procedure. If the goal is to obtain a generalized strain distribution for adaptive bone remodeling algorithms, then traditional SO is likely sufficient. In cases were strain magnitudes are critical, as is the case with fracture risk assessment, bone strain estimation may benefit by including muscle activation and contractile <span class="hlt">dynamics</span> in SO, or by using FD when practical. PMID:26994784</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20010021133','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20010021133"><span id="translatedtitle">A Bell-Curved Based Algorithm for Mixed Continuous and Discrete Structural <span class="hlt">Optimization</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kincaid, Rex K.; Weber, Michael; Sobieszczanski-Sobieski, Jaroslaw</p> <p>2001-01-01</p> <p>An evolutionary based strategy utilizing two normal distributions to generate children is developed to solve <span class="hlt">mixed</span> <span class="hlt">integer</span> nonlinear programming problems. This Bell-Curve Based (BCB) evolutionary algorithm is similar in spirit to (mu + mu) evolutionary strategies and evolutionary programs but with fewer parameters to adjust and no mechanism for self adaptation. First, a new version of BCB to solve purely discrete <span class="hlt">optimization</span> problems is described and its performance tested against a tabu search code for an actuator placement problem. Next, the performance of a combined version of discrete and continuous BCB is tested on 2-dimensional shape problems and on a minimum weight hub design problem. In the latter case the discrete portion is the choice of the underlying beam shape (I, triangular, circular, rectangular, or U).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009ITEIS.129...59O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009ITEIS.129...59O"><span id="translatedtitle"><span class="hlt">Optimal</span> Design of CSD Coefficient FIR Filters Subject to Number of Nonzero Digits</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ozaki, Yuichi; Suyama, Kenji</p> <p></p> <p>In a hardware implementation of FIR(Finite Impulse Response) digital filters, it is desired to reduce a total number of nonzero digits used for a representation of filter coefficients. In general, a design problem of FIR filters with CSD(Canonic Signed Digit) representation, which is efficient one for the reduction of numbers of multiplier units, is often considered as one of the 0-1 combinational problems. In such the problem, some difficult constraints make us prevent to linearize the problem. Although many kinds of heuristic approaches have been applied to solve the problem, the solution obtained by such a manner could not guarantee its <span class="hlt">optimality</span>. In this paper, we attempt to formulate the design problem as the 0-1 <span class="hlt">mixed</span> <span class="hlt">integer</span> linear programming problem and solve it by using the branch and bound technique, which is a powerful method for solving integer programming problem. Several design examples are shown to present an efficient performance of the proposed method.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011PhDT.......132A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011PhDT.......132A"><span id="translatedtitle">Combined <span class="hlt">optimization</span> model for sustainable energization strategy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Abtew, Mohammed Seid</p> <p></p> <p>Access to energy is a foundation to establish a positive impact on multiple aspects of human development. Both developed and developing countries have a common concern of achieving a sustainable energy supply to fuel economic growth and improve the quality of life with minimal environmental impacts. The Least Developing Countries (LDCs), however, have different economic, social, and energy systems. Prevalence of power outage, lack of access to electricity, structural dissimilarity between rural and urban regions, and traditional fuel dominance for cooking and the resultant health and environmental hazards are some of the distinguishing characteristics of these nations. Most energy planning models have been designed for developed countries' socio-economic demographics and have missed the opportunity to address special features of the poor countries. An improved <span class="hlt">mixed-integer</span> programming energy-source <span class="hlt">optimization</span> model is developed to address limitations associated with using current energy <span class="hlt">optimization</span> models for LDCs, tackle development of the sustainable energization strategies, and ensure diversification and risk management provisions in the selected energy mix. The Model predicted a shift from traditional fuels reliant and weather vulnerable energy source mix to a least cost and reliable modern clean energy sources portfolio, a climb on the energy ladder, and scored multifaceted economic, social, and environmental benefits. At the same time, it represented a transition strategy that evolves to increasingly cleaner energy technologies with growth as opposed to an expensive solution that leapfrogs immediately to the cleanest possible, overreaching technologies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/17280730','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/17280730"><span id="translatedtitle">A <span class="hlt">dynamic</span>, <span class="hlt">optimal</span> disease control model for foot-and-mouth-disease: II. Model results and policy implications.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kobayashi, Mimako; Carpenter, Tim E; Dickey, Bradley F; Howitt, Richard E</p> <p>2007-05-16</p> <p>A <span class="hlt">dynamic</span> <span class="hlt">optimization</span> model was used to search for <span class="hlt">optimal</span> strategies to control foot-and-mouth disease (FMD) in the three-county region in the Central Valley of California. The model minimized total regional epidemic cost by choosing the levels of depopulation of diagnosed herds, preemptive depopulation, and vaccination. Impacts of limited carcass disposal capacity and vaccination were also examined, and the shadow value, the implicit value of each capacity, was estimated. The model found that to control FMD in the region, (1) preemptive depopulation was not <span class="hlt">optimal</span>, (2) vaccination, if allowed, was <span class="hlt">optimal</span>, reducing total cost by 3-7%, (3) increased vaccination capacity reduced total cost up to US$119 per dose, (4) increased carcass disposal capacity reduced total cost by US$9000-59,400 per head with and without vaccination, respectively, and (5) dairy operations should be given preferential attention in allocating limited control resources. PMID:17280730</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25170524','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25170524"><span id="translatedtitle"><span class="hlt">Optimization</span> of a continuous hybrid impeller mixer via computational fluid <span class="hlt">dynamics</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Othman, N; Kamarudin, S K; Takriff, M S; Rosli, M I; Engku Chik, E M F; Meor Adnan, M A K</p> <p>2014-01-01</p> <p>This paper presents the preliminary steps required for conducting experiments to obtain the <span class="hlt">optimal</span> operating conditions of a hybrid impeller mixer and to determine the residence time distribution (RTD) using computational fluid <span class="hlt">dynamics</span> (CFD). In this paper, impeller speed and clearance parameters are examined. The hybrid impeller mixer consists of a single Rushton turbine mounted above a single pitched blade turbine (PBT). Four impeller speeds, 50, 100, 150, and 200 rpm, and four impeller clearances, 25, 50, 75, and 100 mm, were the operation variables used in this study. CFD was utilized to initially screen the parameter ranges to reduce the number of actual experiments needed. Afterward, the residence time distribution (RTD) was determined using the respective parameters. Finally, the Fluent-predicted RTD and the experimentally measured RTD were compared. The CFD investigations revealed that an impeller speed of 50 rpm and an impeller clearance of 25 mm were not viable for experimental investigations and were thus eliminated from further analyses. The determination of RTD using a k-? turbulence model was performed using CFD techniques. The multiple reference frame (MRF) was implemented and a steady state was initially achieved followed by a transient condition for RTD determination. PMID:25170524</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20797895','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20797895"><span id="translatedtitle">The <span class="hlt">Optimization</span> of the Ergodic Structure of the <span class="hlt">Dynamic</span> Ergodic Divertor In The TEXTOR Tokamak</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Jakubowski, M. W.; Abdullaev, S. S.; Finken, K. H.; Kikuchi, Y.; Kraemer-Flecken, A.; Lehnen, M.; Schmitz, O.; Unterberg, B.; Wolf, R. C.</p> <p>2006-01-15</p> <p>The <span class="hlt">dynamic</span> ergodic divertor (DED) in TEXTOR is designed to provide a perturbed volume in the plasma edge in order to control heat and particle exhaust. The stochastic boundary layer is generated in the outermost region of the plasma, which can be divided into ergodic and laminar regions. The topology of the magnetic field is substantial for the transport properties and plasma parameters. It is expected that the formation of the proper laminar zone allows decoupling the plasma edge from the core. Due to enhancement of the radial electron heat transport in the ergodic region the electron temperature in the plasma boundary is reduced. Therefore one needs to find the proper ratio of the ergodic and laminar zone, which gives <span class="hlt">optimal</span> performance of the divertor. The structure of the perturbed volume strongly depends on the safety factor profile and the plasma pressure. At the higher level of ergodization (i.e. at higher plasma current and lower beta poloidal) the laminar zone is dominant, while at the lower level of ergodization the ergodic region is more important. The topology of the perturbed volume is modeled with the ATLAS-code and basing on the results of modeling the experiments are performed and compared to the calculated structures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22415526','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22415526"><span id="translatedtitle"><span class="hlt">Optimized</span> molecular reconstruction procedure combining hybrid reverse Monte Carlo and molecular <span class="hlt">dynamics</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bousige, Colin; Boţan, Alexandru; Coasne, Benoît; Ulm, Franz-Josef; Pellenq, Roland J.-M.</p> <p>2015-03-21</p> <p>We report an efficient atom-scale reconstruction method that consists of combining the Hybrid Reverse Monte Carlo algorithm (HRMC) with Molecular <span class="hlt">Dynamics</span> (MD) in the framework of a simulated annealing technique. In the spirit of the experimentally constrained molecular relaxation technique [Biswas et al., Phys. Rev. B 69, 195207 (2004)], this modified procedure offers a refined strategy in the field of reconstruction techniques, with special interest for heterogeneous and disordered solids such as amorphous porous materials. While the HRMC method generates physical structures, thanks to the use of energy penalties, the combination with MD makes the method at least one order of magnitude faster than HRMC simulations to obtain structures of similar quality. Furthermore, in order to ensure the transferability of this technique, we provide rational arguments to select the various input parameters such as the relative weight ω of the energy penalty with respect to the structure <span class="hlt">optimization</span>. By applying the method to disordered porous carbons, we show that adsorption properties provide data to test the global texture of the reconstructed sample but are only weakly sensitive to the presence of defects. In contrast, the vibrational properties such as the phonon density of states are found to be very sensitive to the local structure of the sample.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26562334','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26562334"><span id="translatedtitle">Modeling the motor cortex: <span class="hlt">Optimality</span>, recurrent neural networks, and spatial <span class="hlt">dynamics</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tanaka, Hirokazu</p> <p>2016-03-01</p> <p>Specialization of motor function in the frontal lobe was first discovered in the seminal experiments by Fritsch and Hitzig and subsequently by Ferrier in the 19th century. It is, however, ironical that the functional and computational role of the motor cortex still remains unresolved. A computational understanding of the motor cortex equals to understanding what movement variables the motor neurons represent (movement representation problem) and how such movement variables are computed through the interaction with anatomically connected areas (neural computation problem). Electrophysiological experiments in the 20th century demonstrated that the neural activities in motor cortex correlated with a number of motor-related and cognitive variables, thereby igniting the controversy over movement representations in motor cortex. Despite substantial experimental efforts, the overwhelming complexity found in neural activities has impeded our understanding of how movements are represented in the motor cortex. Recent progresses in computational modeling have rekindled this controversy in the 21st century. Here, I review the recent developments in computational models of the motor cortex, with a focus on <span class="hlt">optimality</span> models, recurrent neural network models and spatial <span class="hlt">dynamics</span> models. Although individual models provide consistent pictures within their domains, our current understanding about functions of the motor cortex is still fragmented. PMID:26562334</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010SJADS...9..154D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010SJADS...9..154D"><span id="translatedtitle"><span class="hlt">Optimal</span> Intrinsic <span class="hlt">Dynamics</span> for Bursting in a Three-Cell Network</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dunmyre, Justin R.; Rubin, Jonathan E.</p> <p>2010-01-01</p> <p>Previous numerical and analytical work has shown that synaptic coupling can allow a network of model neurons to synchronize despite heterogeneity in intrinsic parameter values. In particular, synchronous bursting oscillations can arise in a network with excitatory synaptic coupling, even in the absence of intrinsically bursting neurons. In this work, we explore how the intrinsic <span class="hlt">dynamics</span> of neurons within a reduced three-cell network influence its ability to exhibit synchronous bursting and the frequency range over which such activity can occur. We establish necessary and sufficient conditions for the existence of synchronous bursting solutions and perform related numerical experiments in three-cell networks that include a quiescent cell, a tonically active cell, and a third added cell. Our results show that, in most cases, the addition of a quiescent cell is <span class="hlt">optimal</span> for synchronous network bursting, in a variety of ways, and that intrinsically bursting cells can be detrimental to synchronous bursting, and we explain the mechanisms underlying these effects. These findings may help explain how robust synchronous oscillations arise in neuronal central pattern generators, such as the mammalian inspiratory network, despite the presence of significant cellular heterogeneity. They also support the idea that intrinsic burst capabilities of individual cells need not be central to these networks' rhythms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1990JChPh..93..822H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1990JChPh..93..822H"><span id="translatedtitle">Polypeptide <span class="hlt">dynamics</span>: Experimental tests of an <span class="hlt">optimized</span> Rouse-Zimm type model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hu, Yi; MacInnis, Jean M.; Cherayil, Binny J.; Fleming, Graham R.; Freed, Karl F.; Perico, Angelo</p> <p>1990-07-01</p> <p>A theory for long time random coil peptide <span class="hlt">dynamics</span> is developed based on a generalization of the <span class="hlt">optimized</span> Rouse-Zimm model of Perico et al. [J. Chem. Phys. 87, 3677 (1987)] and Perico [J. Chem. Phys. 88, 3996 (1988) and Biopolymers 28, 1527 (1989)]. The generalized model employs the rotational potential energy for specific amino acid residues and amino acid friction coefficients to compute all input parameters in the model. Calculations of the fluorescence depolarization correlation function P2(t ) and of the local persistence length are found to be sensitive to the amino acid sequence, the length of the polypeptide chain, and the location of the probe. Model computations of P2(t ) are compared with new experimentally determined rotational correlation times (of the order of nanoseconds) from fluorescence depolarization measurements of three different synthetic 17-residue peptides, each containing a single tryptophan (TRP) residue as a probe. In addition, the previous anisotropy measurements on ACTH, glucagon, and their fragments are discussed and compared with the model calculations. Our results indicate that the theory gives a reasonable prediction for the fluorescence depolarization correlation times of random coil polypeptides, but the calculated rotational correlation function predicts a much faster initial decay and a slower final decay than is observed. Possible theoretical improvements are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4124253','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4124253"><span id="translatedtitle"><span class="hlt">Optimization</span> of a Continuous Hybrid Impeller Mixer via Computational Fluid <span class="hlt">Dynamics</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Othman, N.; Kamarudin, S. K.; Takriff, M. S.; Rosli, M. I.; Engku Chik, E. M. F.; Meor Adnan, M. A. K.</p> <p>2014-01-01</p> <p>This paper presents the preliminary steps required for conducting experiments to obtain the <span class="hlt">optimal</span> operating conditions of a hybrid impeller mixer and to determine the residence time distribution (RTD) using computational fluid <span class="hlt">dynamics</span> (CFD). In this paper, impeller speed and clearance parameters are examined. The hybrid impeller mixer consists of a single Rushton turbine mounted above a single pitched blade turbine (PBT). Four impeller speeds, 50, 100, 150, and 200 rpm, and four impeller clearances, 25, 50, 75, and 100 mm, were the operation variables used in this study. CFD was utilized to initially screen the parameter ranges to reduce the number of actual experiments needed. Afterward, the residence time distribution (RTD) was determined using the respective parameters. Finally, the Fluent-predicted RTD and the experimentally measured RTD were compared. The CFD investigations revealed that an impeller speed of 50 rpm and an impeller clearance of 25 mm were not viable for experimental investigations and were thus eliminated from further analyses. The determination of RTD using a k-ε turbulence model was performed using CFD techniques. The multiple reference frame (MRF) was implemented and a steady state was initially achieved followed by a transient condition for RTD determination. PMID:25170524</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/934584','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/934584"><span id="translatedtitle">Merging spatially variant physical process models under an <span class="hlt">optimized</span> systems <span class="hlt">dynamics</span> framework.</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Cain, William O.; Lowry, Thomas Stephen; Pierce, Suzanne A.; Tidwell, Vincent Carroll</p> <p>2007-10-01</p> <p>The complexity of water resource issues, its interconnectedness to other systems, and the involvement of competing stakeholders often overwhelm decision-makers and inhibit the creation of clear management strategies. While a range of modeling tools and procedures exist to address these problems, they tend to be case specific and generally emphasize either a quantitative and overly analytic approach or present a qualitative dialogue-based approach lacking the ability to fully explore consequences of different policy decisions. The integration of these two approaches is needed to drive toward final decisions and engender effective outcomes. Given these limitations, the Computer Assisted Dispute Resolution system (CADRe) was developed to aid in stakeholder inclusive resource planning. This modeling and negotiation system uniquely addresses resource concerns by developing a spatially varying system <span class="hlt">dynamics</span> model as well as innovative global <span class="hlt">optimization</span> search techniques to maximize outcomes from participatory dialogues. Ultimately, the core system architecture of CADRe also serves as the cornerstone upon which key scientific innovation and challenges can be addressed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20030033869','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20030033869"><span id="translatedtitle">Using Plate Finite Elements for Modeling Fillets in Design, <span class="hlt">Optimization</span>, and <span class="hlt">Dynamic</span> Analysis</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Brown, A. M.; Seugling, R. M.</p> <p>2003-01-01</p> <p>A methodology has been developed that allows the use of plate elements instead of numerically inefficient solid elements for modeling structures with 90 degree fillets. The technique uses plate bridges with pseudo Young's modulus (Eb) and thickness (tb) values placed between the tangent points of the fillets. These parameters are obtained by solving two nonlinear simultaneous equations in terms of the independent variables rlt and twallt. These equations are generated by equating the rotation at the tangent point of a bridge system with that of a fillet, where both rotations are derived using beam theory. Accurate surface fits of the solutions are also presented to provide the user with closed-form equations for the parameters. The methodology was verified on the subcomponent level and with a representative filleted structure, where the technique yielded a plate model exhibiting a level of accuracy better than or equal to a high-fidelity solid model and with a 90-percent reduction in the number of DOFs. The application of this method for parametric design studies, <span class="hlt">optimization</span>, and <span class="hlt">dynamic</span> analysis should prove extremely beneficial for the finite element practitioner. Although the method does not attempt to produce accurate stresses in the filleted region, it can also be used to obtain stresses elsewhere in the structure for preliminary analysis. A future avenue of study is to extend the theory developed here to other fillet geometries, including fillet angles other than 90 and multifaceted intersections.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4364306','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4364306"><span id="translatedtitle">A Two-Stage Method to Determine <span class="hlt">Optimal</span> Product Sampling considering <span class="hlt">Dynamic</span> Potential Market</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hu, Zhineng; Lu, Wei; Han, Bing</p> <p>2015-01-01</p> <p>This paper develops an <span class="hlt">optimization</span> model for the diffusion effects of free samples under <span class="hlt">dynamic</span> changes in potential market based on the characteristics of independent product and presents a two-stage method to figure out the sampling level. The impact analysis of the key factors on the sampling level shows that the increase of the external coefficient or internal coefficient has a negative influence on the sampling level. And the changing rate of the potential market has no significant influence on the sampling level whereas the repeat purchase has a positive one. Using logistic analysis and regression analysis, the global sensitivity analysis gives a whole analysis of the interaction of all parameters, which provides a two-stage method to estimate the impact of the relevant parameters in the case of inaccuracy of the parameters and to be able to construct a 95% confidence interval for the predicted sampling level. Finally, the paper provides the operational steps to improve the accuracy of the parameter estimation and an innovational way to estimate the sampling level. PMID:25821847</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25821847','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25821847"><span id="translatedtitle">A two-stage method to determine <span class="hlt">optimal</span> product sampling considering <span class="hlt">dynamic</span> potential market.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hu, Zhineng; Lu, Wei; Han, Bing</p> <p>2015-01-01</p> <p>This paper develops an <span class="hlt">optimization</span> model for the diffusion effects of free samples under <span class="hlt">dynamic</span> changes in potential market based on the characteristics of independent product and presents a two-stage method to figure out the sampling level. The impact analysis of the key factors on the sampling level shows that the increase of the external coefficient or internal coefficient has a negative influence on the sampling level. And the changing rate of the potential market has no significant influence on the sampling level whereas the repeat purchase has a positive one. Using logistic analysis and regression analysis, the global sensitivity analysis gives a whole analysis of the interaction of all parameters, which provides a two-stage method to estimate the impact of the relevant parameters in the case of inaccuracy of the parameters and to be able to construct a 95% confidence interval for the predicted sampling level. Finally, the paper provides the operational steps to improve the accuracy of the parameter estimation and an innovational way to estimate the sampling level. PMID:25821847</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhRvA..92f2110B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhRvA..92f2110B"><span id="translatedtitle">Quantum speed limit and <span class="hlt">optimal</span> control of many-boson <span class="hlt">dynamics</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brouzos, Ioannis; Streltsov, Alexej I.; Negretti, Antonio; Said, Ressa S.; Caneva, Tommaso; Montangero, Simone; Calarco, Tommaso</p> <p>2015-12-01</p> <p>We apply the concept of quantum speed limit (QSL)—the minimal time needed to perform a driven evolution—to complex interacting many-body systems where the effects of interactions have to be taken into account. We introduce a general strategy to eliminate the detrimental effects of the interparticle repulsion and drive the system at the QSL by applying a compensating control pulse (CCP). To prove the principles we consider a prototypical many-body system, a bosonic Josephson junction, and investigate a transfer of atoms from the ground state of one well to the ground state of the neighboring well, at increasing levels of complexity—from a textbook two-level approximation to full many-body treatment. By tracing the efficiency of the CCP protocol we show that the driven <span class="hlt">dynamics</span> does follow the geodetic pathway and, therefore, it is <span class="hlt">optimal</span>. The CCP strategy, applicable for a general interacting quantum many-body system with strong driving, can be of a practical relevance for the experimental implementation of quantum technology protocols, as quantum simulations or matter-wave metrology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3958135','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3958135"><span id="translatedtitle">Weighted Implementation of Suboptimal Paths (WISP): An <span class="hlt">Optimized</span> Algorithm and Tool for <span class="hlt">Dynamical</span> Network Analysis</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2015-01-01</p> <p>Allostery can occur by way of subtle cooperation among protein residues (e.g., amino acids) even in the absence of large conformational shifts. <span class="hlt">Dynamical</span> network analysis has been used to model this cooperation, helping to computationally explain how binding to an allosteric site can impact the behavior of a primary site many ångstroms away. Traditionally, computational efforts have focused on the most <span class="hlt">optimal</span> path of correlated motions leading from the allosteric to the primary active site. We present a program called Weighted Implementation of Suboptimal Paths (WISP) capable of rapidly identifying additional suboptimal pathways that may also play important roles in the transmission of allosteric signals. Aside from providing signal redundancy, suboptimal paths traverse residues that, if disrupted through pharmacological or mutational means, could modulate the allosteric regulation of important drug targets. To demonstrate the utility of our program, we present a case study describing the allostery of HisH-HisF, an amidotransferase from T. maritima thermotiga. WISP and its VMD-based graphical user interface (GUI) can be downloaded from http://nbcr.ucsd.edu/wisp. PMID:24803851</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24804658','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24804658"><span id="translatedtitle">Simulation and <span class="hlt">optimization</span> of airlift external circulation membrane bioreactor using computational fluid <span class="hlt">dynamics</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Qing, Zhang; Rongle, Xu; Xiang, Zheng; Yaobo, Fan</p> <p>2014-01-01</p> <p>The airlift external circulation membrane bioreactor (AEC-MBR) is a new MBR consisting of a separated aeration tank and membrane tank with circulating pipes fixed between the two tanks. The circulating pipe is called a H circulating pipe (HCP) because of its shape. With the complex configuration, it was difficult but necessary to master the AEC-MBR's hydraulic characteristics. In this paper, simulation and <span class="hlt">optimization</span> of the AEC-MBR was performed using computational fluid <span class="hlt">dynamics</span>. The distance from diffusers to membrane modules, i.e. the height of gas-liquid mixing zone (h(m)), and its effect on velocity distribution at membrane surfaces were studied. Additionally, the role of HCP and the effect of HCP's diameter on circulation were simulated and analyzed. The results showed that non-uniformity of cross-flow velocity existed in the flat-plate membrane modules, and the problem could be alleviated by increasing hm to an optimum range (h(m)/B ≥ 0.55; B is total static depth). Also, the low velocity in the boundary layer on the membrane surface was another reason for membrane fouling. The results also suggested that HCP was necessary and it had an optimum diameter to make circulation effective in the AEC-MBR. PMID:24804658</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009CoPhC.180.2472L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009CoPhC.180.2472L"><span id="translatedtitle">MonALISA: An agent based, <span class="hlt">dynamic</span> service system to monitor, control and <span class="hlt">optimize</span> distributed systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Legrand, I.; Newman, H.; Voicu, R.; Cirstoiu, C.; Grigoras, C.; Dobre, C.; Muraru, A.; Costan, A.; Dediu, M.; Stratan, C.</p> <p>2009-12-01</p> <p>The MonALISA (Monitoring Agents in a Large Integrated Services Architecture) framework provides a set of distributed services for monitoring, control, management and global <span class="hlt">optimization</span> for large scale distributed systems. It is based on an ensemble of autonomous, multi-threaded, agent-based subsystems which are registered as <span class="hlt">dynamic</span> services. They can be automatically discovered and used by other services or clients. The distributed agents can collaborate and cooperate in performing a wide range of management, control and global <span class="hlt">optimization</span> tasks using real time monitoring information. Program summaryProgram title: MonALISA Catalogue identifier: AEEZ_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEEZ_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Caltech License - free for all non-commercial activities No. of lines in distributed program, including test data, etc.: 147 802 No. of bytes in distributed program, including test data, etc.: 2 5913 689 Distribution format: tar.gz Programming language: Java, additional APIs available in Java, C, C++, Perl and python Computer: Computing Clusters, Network Devices, Storage Systems, Large scale data intensive applications Operating system: The MonALISA service is mainly used in Linux, the MonALISA client runs on all major platforms (Windows, Linux, Solaris, MacOS). Has the code been vectorized or parallelized?: It is a multithreaded application. It will efficiently use all the available processors. RAM: for the MonALISA service the minimum required memory is 64 MB; if the JVM is started allocating more memory this will be used for internal caching. The MonALISA client requires typically 256-512 MB of memory. Classification: 6.5 External routines: Requires Java: JRE or JDK to run. These external packages are used (they are included in the distribution): JINI, JFreeChart, PostgreSQL (optional). Nature of problem: To monitor and control distributed computing clusters and grids, the network infrastructure, the storage systems, and the applications used on such facilities. The monitoring information gathered is used for developing the required higher level services, the components that provide decision support and some degree of automated decisions and for maintaining and <span class="hlt">optimizing</span> workflow in large scale distributed systems. Solution method: The MonALISA framework is designed as an ensemble of autonomous self-describing agent-based subsystems which are registered as <span class="hlt">dynamic</span> services. These services are able to collaborate and cooperate in performing a wide range of distributed information-gathering and processing tasks. Running time: MonALISA services are designed to run continuously to collect monitoring data and to trigger alarms or to take automatic actions in case it is necessary. References:http://monalisa.caltech.edu.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1126436','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1126436"><span id="translatedtitle">TAS: 89 0227: TAS Recovery Act - <span class="hlt">Optimization</span> and Control of Electric Power Systems: ARRA</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Chiang, Hsiao-Dong</p> <p>2014-02-01</p> <p>The name SuperOPF is used to refer several projects, problem formulations and soft-ware tools intended to extend, improve and re-define some of the standard methods of <span class="hlt">optimizing</span> electric power systems. Our work included applying primal-dual interior point methods to standard AC <span class="hlt">optimal</span> power flow problems of large size, as well as extensions of this problem to include co-<span class="hlt">optimization</span> of multiple scenarios. The original SuperOPF problem formulation was based on co-<span class="hlt">optimizing</span> a base scenario along with multiple post-contingency scenarios, where all AC power flow models and constraints are enforced for each, to find <span class="hlt">optimal</span> energy contracts, endogenously determined locational reserves and appropriate nodal energy prices for a single period <span class="hlt">optimal</span> power flow problem with uncertainty. This led to example non-linear programming problems on the order of 1 million constraints and half a million variables. The second generation SuperOPF formulation extends this by adding multiple periods and multiple base scenarios per period. It also incorporates additional variables and constraints to model load following reserves, ramping costs, and storage resources. A third generation of the multi-period SuperOPF, adds both integer variables and a receding horizon framework in which the problem type is more challenging (<span class="hlt">mixed</span> <span class="hlt">integer</span>), the size is even larger, and it must be solved more frequently, pushing the limits of currently available algorithms and solvers. The consideration of transient stability constraints in <span class="hlt">optimal</span> power flow (OPF) problems has become increasingly important in modern power systems. Transient stability constrained OPF (TSCOPF) is a nonlinear <span class="hlt">optimization</span> problem subject to a set of algebraic and differential equations. Solving a TSCOPF problem can be challenging due to (i) the differential-equation constraints in an <span class="hlt">optimization</span> problem, (ii) the lack of a true analytical expression for transient stability in OPF. To handle the <span class="hlt">dynamics</span> in TSCOPF, the set of differential equations can be approximated or converted into equivalent algebraic equations before they are included in an OPF formulation. In Chapter 4, a rigorous evaluation of using a predefined and fixed threshold for rotor angles as a mean to determine transient stability of the system is developed. TSCOPF can be modeled as a large-scale nonlinear programming problem including the constraints of differential-algebraic equations (DAE). Solving a TSCOPF problem can be challenging due to (i) the differential-equation constraints in an <span class="hlt">optimization</span> problem, (ii) the lack of a true analytical expression for transient stability constraint in OPF. Unfortunately, even the current best TSCOPF solvers still suffer from the curse of dimensionality and unacceptable computational time, especially for large-scale power systems with multiple contingencies. In chapter 5, thse issues will be addressed and a new method to incorporate the transient stability constraints will be presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhDT.........3C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhDT.........3C"><span id="translatedtitle">Materials <span class="hlt">optimization</span> and ghz spin <span class="hlt">dynamics</span> of metallic ferromagnetic thin film heterostructures</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cheng, Cheng</p> <p></p> <p>Metallic ferromagnetic (FM) thin film heterostructures play an important role in emerging magnetoelectronic devices, which introduce the spin degree of freedom of electrons into conventional charge-based electronic devices. As the majority of magnetoelectronic devices operate in the GHz frequency range, it is critical to understand the high-frequency magnetization <span class="hlt">dynamics</span> in these structures. In this thesis, we start with the static magnetic properties of FM thin films and their <span class="hlt">optimization</span> via the field-sputtering process incorporating a specially designed in-situ electromagnet. We focus on the origins of anisotropy and hysteresis/coercivity in soft magnetic thin films, which are most relevant to magentic susceptibility and power dissipation in applications in the sub-GHz frequency regime, such as magnetic-core integrated inductors. Next we explore GHz magnetization <span class="hlt">dynamics</span> in thin-film heterostructures, both in semi-infinite samples and confined geometries. All investigations are rooted in the Landau-Lifshitz-Gilbert (LLG) equation, the equation of motion for magnetization. The phenomenological Gilbert damping parameter in the LLG equation has been interpreted, since the 1970's, in terms of the electrical resistivity. We present the first interpretation of the size effect in Gilbert damping in single metallic FM films based on this electron theory of damping. The LLG equation is intrinsically nonlinear, which provides possibilities for rf signal processing. We analyze the frequency doubling effect at small-angle magnetization precession from the first-order expansion of the LLG equation, and demonstrate second harmonic generation from Ni81 Fe19 (Permalloy) thin film under ferromagnetic resonance (FMR), three orders of magnitude more efficient than in ferrites traditionally used in rf devices. Though the efficiency is less than in semiconductor devices, we provide field- and frequency-selectivity in the second harmonic generation. To address further the relationship between the rf excitation and the magnetization <span class="hlt">dynamics</span> in systems with higher complexity, such as multilayered thin films consisting of nonmagnetic (NM) and FM layers, we employ the powerful time-resolved x-ray magnetic circular dichroism (TR-XMCD) spectroscopy. Soft x-rays have element-specific absorption, leading to layer-specific magnetization detection provided the FM layers have distinctive compositions. We discovered that in contrast to what has been routinely assumed, for layer thicknesses well below the skin depth of the EM wave, a significant phase difference exists between the rf magnetic fields H rf in different FM layers separated by a Cu spacer layer. We propose an analysis based on the distribution of the EM waves in the film stack and substrate to interpret this striking observation. For confined geometries with lateral dimensions in the sub-micron regime, there has been a critical absence of experimental techniques which can image small-amplitude <span class="hlt">dynamics</span> of these structures. We extend the TR-XMCD technique to scanning transmission x-ray microscopy (STXM), to observe directly the local magnetization <span class="hlt">dynamics</span> in nanoscale FM thin-film elements, demonstrated at picosecond temporal, 40 nm spatial and < 6° angular resolution. The experimental data are compared with our micromagnetic simulations based on the finite element analysis of the time-dependent LLG equation. We resolve standing spin wave modes in nanoscale Ni81 Fe19 thin film ellipses (1000 nm x 500 nm x 20 nm) with clear phase information to distinguish between degenerate eigenmodes with different symmetries for the first time. With the element-specific imaging capability of soft x-rays, spatial resolution up to 15 nm with improved optics, we see great potential for this technique to investigate functional devices with multiple FM layers, and provide insight into the studies of spin injection, manipulation and detection.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4767795','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4767795"><span id="translatedtitle">Anode <span class="hlt">optimization</span> for miniature electronic brachytherapy X-ray sources using Monte Carlo and computational fluid <span class="hlt">dynamic</span> codes</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Khajeh, Masoud; Safigholi, Habib</p> <p>2015-01-01</p> <p>A miniature X-ray source has been <span class="hlt">optimized</span> for electronic brachytherapy. The cooling fluid for this device is water. Unlike the radionuclide brachytherapy sources, this source is able to operate at variable voltages and currents to match the dose with the tumor depth. First, Monte Carlo (MC) <span class="hlt">optimization</span> was performed on the tungsten target-buffer thickness layers versus energy such that the minimum X-ray attenuation occurred. Second <span class="hlt">optimization</span> was done on the selection of the anode shape based on the Monte Carlo in water TG-43U1 anisotropy function. This <span class="hlt">optimization</span> was carried out to get the dose anisotropy functions closer to unity at any angle from 0° to 170°. Three anode shapes including cylindrical, spherical, and conical were considered. Moreover, by Computational Fluid <span class="hlt">Dynamic</span> (CFD) code the <span class="hlt">optimal</span> target-buffer shape and different nozzle shapes for electronic brachytherapy were evaluated. The characterization criteria of the CFD were the minimum temperature on the anode shape, cooling water, and pressure loss from inlet to outlet. The <span class="hlt">optimal</span> anode was conical in shape with a conical nozzle. Finally, the TG-43U1 parameters of the <span class="hlt">optimal</span> source were compared with the literature. PMID:26966563</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26966563','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26966563"><span id="translatedtitle">Anode <span class="hlt">optimization</span> for miniature electronic brachytherapy X-ray sources using Monte Carlo and computational fluid <span class="hlt">dynamic</span> codes.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Khajeh, Masoud; Safigholi, Habib</p> <p>2016-03-01</p> <p>A miniature X-ray source has been <span class="hlt">optimized</span> for electronic brachytherapy. The cooling fluid for this device is water. Unlike the radionuclide brachytherapy sources, this source is able to operate at variable voltages and currents to match the dose with the tumor depth. First, Monte Carlo (MC) <span class="hlt">optimization</span> was performed on the tungsten target-buffer thickness layers versus energy such that the minimum X-ray attenuation occurred. Second <span class="hlt">optimization</span> was done on the selection of the anode shape based on the Monte Carlo in water TG-43U1 anisotropy function. This <span class="hlt">optimization</span> was carried out to get the dose anisotropy functions closer to unity at any angle from 0° to 170°. Three anode shapes including cylindrical, spherical, and conical were considered. Moreover, by Computational Fluid <span class="hlt">Dynamic</span> (CFD) code the <span class="hlt">optimal</span> target-buffer shape and different nozzle shapes for electronic brachytherapy were evaluated. The characterization criteria of the CFD were the minimum temperature on the anode shape, cooling water, and pressure loss from inlet to outlet. The <span class="hlt">optimal</span> anode was conical in shape with a conical nozzle. Finally, the TG-43U1 parameters of the <span class="hlt">optimal</span> source were compared with the literature. PMID:26966563</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1231284','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1231284"><span id="translatedtitle">DAKOTA Design Analysis Kit for <span class="hlt">Optimization</span> and Terascale</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Adams, Brian M.; Dalbey, Keith R.; Eldred, Michael S.; Gay, David M.; Swiler, Laura P.; Bohnhoff, William J.; Eddy, John P.; Haskell, Karen</p> <p>2010-02-24</p> <p>The DAKOTA (Design Analysis Kit for <span class="hlt">Optimization</span> and Terascale Applications) toolkit provides a flexible and extensible interface between simulation codes (computational models) and iterative analysis methods. By employing object-oriented design to implement abstractions of the key components required for iterative systems analyses, the DAKOTA toolkit provides a flexible and extensible problem-solving environment for design and analysis of computational models on high performance computers.A user provides a set of DAKOTA commands in an input file and launches DAKOTA. DAKOTA invokes instances of the computational models, collects their results, and performs systems analyses. DAKOTA contains algorithms for <span class="hlt">optimization</span> with gradient and nongradient-based methods; uncertainty quantification with sampling, reliability, polynomial chaos, stochastic collocation, and epistemic methods; parameter estimation with nonlinear least squares methods; and sensitivity/variance analysis with design of experiments and parameter study methods. These capabilities may be used on their own or as components within advanced strategies such as hybrid <span class="hlt">optimization</span>, surrogate-based <span class="hlt">optimization</span>, <span class="hlt">mixed</span> <span class="hlt">integer</span> nonlinear programming, or <span class="hlt">optimization</span> under uncertainty. Services for parallel computing, simulation interfacing, approximation modeling, fault tolerance, restart, and graphics are also included.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1231284-dakota-design-analysis-kit-optimization-terascale','SCIGOV-ESTSC'); return false;" href="http://www.osti.gov/scitech/biblio/1231284-dakota-design-analysis-kit-optimization-terascale"><span id="translatedtitle">DAKOTA Design Analysis Kit for <span class="hlt">Optimization</span> and Terascale</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech/">Energy Science and Technology Software Center (ESTSC)</a></p> <p></p> <p>2010-02-24</p> <p>The DAKOTA (Design Analysis Kit for <span class="hlt">Optimization</span> and Terascale Applications) toolkit provides a flexible and extensible interface between simulation codes (computational models) and iterative analysis methods. By employing object-oriented design to implement abstractions of the key components required for iterative systems analyses, the DAKOTA toolkit provides a flexible and extensible problem-solving environment for design and analysis of computational models on high performance computers.A user provides a set of DAKOTA commands in an input file andmore » launches DAKOTA. DAKOTA invokes instances of the computational models, collects their results, and performs systems analyses. DAKOTA contains algorithms for <span class="hlt">optimization</span> with gradient and nongradient-based methods; uncertainty quantification with sampling, reliability, polynomial chaos, stochastic collocation, and epistemic methods; parameter estimation with nonlinear least squares methods; and sensitivity/variance analysis with design of experiments and parameter study methods. These capabilities may be used on their own or as components within advanced strategies such as hybrid <span class="hlt">optimization</span>, surrogate-based <span class="hlt">optimization</span>, <span class="hlt">mixed</span> <span class="hlt">integer</span> nonlinear programming, or <span class="hlt">optimization</span> under uncertainty. Services for parallel computing, simulation interfacing, approximation modeling, fault tolerance, restart, and graphics are also included.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1155115','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1155115"><span id="translatedtitle">REopt: A Platform for Energy System Integration and <span class="hlt">Optimization</span>: Preprint</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Simpkins, T.; Cutler, D.; Anderson, K.; Olis, D.; Elgqvist, E.; Callahan, M.; Walker, A.</p> <p>2014-08-01</p> <p>REopt is NREL's energy planning platform offering concurrent, multi-technology integration and <span class="hlt">optimization</span> capabilities to help clients meet their cost savings and energy performance goals. The REopt platform provides techno-economic decision-support analysis throughout the energy planning process, from agency-level screening and macro planning to project development to energy asset operation. REopt employs an integrated approach to <span class="hlt">optimizing</span> a site?s energy costs by considering electricity and thermal consumption, resource availability, complex tariff structures including time-of-use, demand and sell-back rates, incentives, net-metering, and interconnection limits. Formulated as a <span class="hlt">mixed</span> <span class="hlt">integer</span> linear program, REopt recommends an <span class="hlt">optimally</span>-sized mix of conventional and renewable energy, and energy storage technologies; estimates the net present value associated with implementing those technologies; and provides the cost-<span class="hlt">optimal</span> dispatch strategy for operating them at maximum economic efficiency. The REopt platform can be customized to address a variety of energy <span class="hlt">optimization</span> scenarios including policy, microgrid, and operational energy applications. This paper presents the REopt techno-economic model along with two examples of recently completed analysis projects.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/17677168','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/17677168"><span id="translatedtitle">Development of <span class="hlt">optimal</span> models of porous media by combining static and <span class="hlt">dynamic</span> data: the permeability and porosity distributions.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hamzehpour, Hossein; Rasaei, M Reza; Sahimi, Muhammad</p> <p>2007-05-01</p> <p>We describe a method for the development of the <span class="hlt">optimal</span> spatial distributions of the porosity phi and permeability k of a large-scale porous medium. The <span class="hlt">optimal</span> distributions are constrained by static and <span class="hlt">dynamic</span> data. The static data that we utilize are limited data for phi and k, which the method honors in the <span class="hlt">optimal</span> model and utilizes their correlation functions in the <span class="hlt">optimization</span> process. The <span class="hlt">dynamic</span> data include the first-arrival (FA) times, at a number of receivers, of seismic waves that have propagated in the porous medium, and the time-dependent production rates of a fluid that flows in the medium. The method combines the simulated-annealing method with a simulator that solves numerically the three-dimensional (3D) acoustic wave equation and computes the FA times, and a second simulator that solves the 3D governing equation for the fluid's pressure as a function of time. To our knowledge, this is the first time that an <span class="hlt">optimization</span> method has been developed to determine simultaneously the global minima of two distinct total energy functions. As a stringent test of the method's accuracy, we solve for flow of two immiscible fluids in the same porous medium, without using any data for the two-phase flow problem in the <span class="hlt">optimization</span> process. We show that the <span class="hlt">optimal</span> model, in addition to honoring the data, also yields accurate spatial distributions of phi and k, as well as providing accurate quantitative predictions for the single- and two-phase flow problems. The efficiency of the computations is discussed in detail. PMID:17677168</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4667038','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4667038"><span id="translatedtitle"><span class="hlt">Optimal</span> multi-floor plant layout based on the mathematical programming and particle swarm <span class="hlt">optimization</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>LEE, Chang Jun</p> <p>2015-01-01</p> <p>In the fields of researches associated with plant layout <span class="hlt">optimization</span>, the main goal is to minimize the costs of pipelines and pumping between connecting equipment under various constraints. However, what is the lacking of considerations in previous researches is to transform various heuristics or safety regulations into mathematical equations. For example, proper safety distances between equipments have to be complied for preventing dangerous accidents on a complex plant. Moreover, most researches have handled single-floor plant. However, many multi-floor plants have been constructed for the last decade. Therefore, the proper algorithm handling various regulations and multi-floor plant should be developed. In this study, the <span class="hlt">Mixed</span> <span class="hlt">Integer</span> Non-Linear Programming (MINLP) problem including safety distances, maintenance spaces, etc. is suggested based on mathematical equations. The objective function is a summation of pipeline and pumping costs. Also, various safety and maintenance issues are transformed into inequality or equality constraints. However, it is really hard to solve this problem due to complex nonlinear constraints. Thus, it is impossible to use conventional MINLP solvers using derivatives of equations. In this study, the Particle Swarm <span class="hlt">Optimization</span> (PSO) technique is employed. The ethylene oxide plant is illustrated to verify the efficacy of this study. PMID:26027708</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26027708','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26027708"><span id="translatedtitle"><span class="hlt">Optimal</span> multi-floor plant layout based on the mathematical programming and particle swarm <span class="hlt">optimization</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lee, Chang Jun</p> <p>2015-01-01</p> <p>In the fields of researches associated with plant layout <span class="hlt">optimization</span>, the main goal is to minimize the costs of pipelines and pumping between connecting equipment under various constraints. However, what is the lacking of considerations in previous researches is to transform various heuristics or safety regulations into mathematical equations. For example, proper safety distances between equipments have to be complied for preventing dangerous accidents on a complex plant. Moreover, most researches have handled single-floor plant. However, many multi-floor plants have been constructed for the last decade. Therefore, the proper algorithm handling various regulations and multi-floor plant should be developed. In this study, the <span class="hlt">Mixed</span> <span class="hlt">Integer</span> Non-Linear Programming (MINLP) problem including safety distances, maintenance spaces, etc. is suggested based on mathematical equations. The objective function is a summation of pipeline and pumping costs. Also, various safety and maintenance issues are transformed into inequality or equality constraints. However, it is really hard to solve this problem due to complex nonlinear constraints. Thus, it is impossible to use conventional MINLP solvers using derivatives of equations. In this study, the Particle Swarm <span class="hlt">Optimization</span> (PSO) technique is employed. The ethylene oxide plant is illustrated to verify the efficacy of this study. PMID:26027708</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19980236667','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19980236667"><span id="translatedtitle">Unstructured Finite Volume Computational Thermo-Fluid <span class="hlt">Dynamic</span> Method for Multi-Disciplinary Analysis and Design <span class="hlt">Optimization</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Majumdar, Alok; Schallhorn, Paul</p> <p>1998-01-01</p> <p>This paper describes a finite volume computational thermo-fluid <span class="hlt">dynamics</span> method to solve for Navier-Stokes equations in conjunction with energy equation and thermodynamic equation of state in an unstructured coordinate system. The system of equations have been solved by a simultaneous Newton-Raphson method and compared with several benchmark solutions. Excellent agreements have been obtained in each case and the method has been found to be significantly faster than conventional Computational Fluid <span class="hlt">Dynamic</span>(CFD) methods and therefore has the potential for implementation in Multi-Disciplinary analysis and design <span class="hlt">optimization</span> in fluid and thermal systems. The paper also describes an algorithm of design <span class="hlt">optimization</span> based on Newton-Raphson method which has been recently tested in a turbomachinery application.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1011826','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1011826"><span id="translatedtitle"><span class="hlt">Optimal</span> response to attacks on the open science grids.</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Altunay, M.; Leyffer, S.; Linderoth, J. T.; Xie, Z.</p> <p>2011-01-01</p> <p>Cybersecurity is a growing concern, especially in open grids, where attack propagation is easy because of prevalent collaborations among thousands of users and hundreds of institutions. The collaboration rules that typically govern large science experiments as well as social networks of scientists span across the institutional security boundaries. A common concern is that the increased openness may allow malicious attackers to spread more readily around the grid. We consider how to <span class="hlt">optimally</span> respond to attacks in open grid environments. To show how and why attacks spread more readily around the grid, we first discuss how collaborations manifest themselves in the grids and form the collaboration network graph, and how this collaboration network graph affects the security threat levels of grid participants. We present two <span class="hlt">mixed-integer</span> program (MIP) models to find the <span class="hlt">optimal</span> response to attacks in open grid environments, and also calculate the threat level associated with each grid participant. Given an attack scenario, our <span class="hlt">optimal</span> response model aims to minimize the threat levels at unaffected participants while maximizing the uninterrupted scientific production (continuing collaborations). By adopting some of the collaboration rules (e.g., suspending a collaboration or shutting down a site), the model finds <span class="hlt">optimal</span> response to subvert an attack scenario.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AcNum..13..271N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AcNum..13..271N"><span id="translatedtitle">Complete search in continuous global <span class="hlt">optimization</span> and constraint satisfaction</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Neumaier, Arnold</p> <p></p> <p>This survey covers the state of the art of techniques for solving general-purpose constrained global <span class="hlt">optimization</span> problems and continuous constraint satisfaction problems, with emphasis on complete techniques that provably find all solutions (if there are finitely many). The core of the material is presented in sufficient detail that the survey may serve as a text for teaching constrained global <span class="hlt">optimization</span>.After giving motivations for and important examples of applications of global <span class="hlt">optimization</span>, a precise problem definition is given, and a general form of the traditional first-order necessary conditions for a solution. Then more than a dozen software packages for complete global search are described.A quick review of incomplete methods for bound-constrained problems and recipes for their use in the constrained case follows; an explicit example is discussed, introducing the main techniques used within branch and bound techniques. Sections on interval arithmetic, constrained propagation and local <span class="hlt">optimization</span> are followed by a discussion of how to avoid the cluster problem. Then a discussion of important problem transformations follows, in particular of linear, convex, and semilinear (= <span class="hlt">mixed</span> <span class="hlt">integer</span> linear) relaxations that are important for handling larger problems.Next, reliability issues - centring on rounding error handling and testing methodologies - are discussed, and the COCONUT framework for the integration of the different techniques is introduced. A list of challenges facing the field in the near future concludes the survey.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014CNSNS..19.3323L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014CNSNS..19.3323L"><span id="translatedtitle">Global resonance <span class="hlt">optimization</span> analysis of nonlinear mechanical systems: Application to the uncertainty quantification problems in rotor <span class="hlt">dynamics</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liao, Haitao</p> <p>2014-09-01</p> <p>An efficient method to obtain the worst quasi-periodic vibration response of nonlinear <span class="hlt">dynamical</span> systems with uncertainties is presented. Based on the multi-dimensional harmonic balance method, a constrained, nonlinear <span class="hlt">optimization</span> problem with the nonlinear equality constraints is derived. The MultiStart <span class="hlt">optimization</span> algorithm is then used to <span class="hlt">optimize</span> the vibration response within the specified range of physical parameters. In order to illustrate the efficiency and ability of the proposed method, several numerical examples are illustrated. The proposed method is then applied to a rotor system with multiple frequency excitations (unbalance and support) under several physical parameters uncertainties. Numerical examples show that the proposed approach is valid and effective for analyzing strongly nonlinear vibration problems with different types of nonlinearities in the presence of uncertainties.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22250904','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22250904"><span id="translatedtitle">Non-linear <span class="hlt">dynamic</span> characteristics and <span class="hlt">optimal</span> control of giant magnetostrictive film subjected to in-plane stochastic excitation</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Zhu, Z. W.; Zhang, W. D. Xu, J.</p> <p>2014-03-15</p> <p>The non-linear <span class="hlt">dynamic</span> characteristics and <span class="hlt">optimal</span> control of a giant magnetostrictive film (GMF) subjected to in-plane stochastic excitation were studied. Non-linear differential items were introduced to interpret the hysteretic phenomena of the GMF, and the non-linear <span class="hlt">dynamic</span> model of the GMF subjected to in-plane stochastic excitation was developed. The stochastic stability was analysed, and the probability density function was obtained. The condition of stochastic Hopf bifurcation and noise-induced chaotic response were determined, and the fractal boundary of the system's safe basin was provided. The reliability function was solved from the backward Kolmogorov equation, and an <span class="hlt">optimal</span> control strategy was proposed in the stochastic <span class="hlt">dynamic</span> programming method. Numerical simulation shows that the system stability varies with the parameters, and stochastic Hopf bifurcation and chaos appear in the process; the area of the safe basin decreases when the noise intensifies, and the boundary of the safe basin becomes fractal; the system reliability improved through stochastic <span class="hlt">optimal</span> control. Finally, the theoretical and numerical results were proved by experiments. The results are helpful in the engineering applications of GMF.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JPS...274..367M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JPS...274..367M"><span id="translatedtitle"><span class="hlt">Optimal</span> economy-based battery degradation management <span class="hlt">dynamics</span> for fuel-cell plug-in hybrid electric vehicles</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Martel, François; Kelouwani, Sousso; Dubé, Yves; Agbossou, Kodjo</p> <p>2015-01-01</p> <p>This work analyses the economical <span class="hlt">dynamics</span> of an <span class="hlt">optimized</span> battery degradation management strategy intended for plug-in hybrid electric vehicles (PHEVs) with consideration given to low-cost technologies, such as lead-acid batteries. The <span class="hlt">optimal</span> management algorithm described herein is based on discrete <span class="hlt">dynamic</span> programming theory (DDP) and was designed for the purpose of PHEV battery degradation management; its operation relies on simulation models using data obtained experimentally on a physical PHEV platform. These tools are first used to define an <span class="hlt">optimal</span> management strategy according to the economical weights of PHEV battery degradation and the secondary energy carriers spent to manage its deleterious effects. We then conduct a sensitivity study of the proposed <span class="hlt">optimization</span> process to the fluctuating economic parameters associated with the fuel and energy costs involved in the degradation management process. Results demonstrate the influence of each parameter on the process's response, including daily total operating costs and expected battery lifetime, as well as establish boundaries for useful application of the method; in addition, they provide a case for the relevance of inexpensive battery technologies, such as lead-acid batteries, for economy-centric PHEV applications where battery degradation is a major concern.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JAnSc..59..237H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JAnSc..59..237H"><span id="translatedtitle"><span class="hlt">Optimal</span> Multi-Impulse Orbit Transfer Using Nonlinear Relative Motion <span class="hlt">Dynamics</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Huang, Weijun</p> <p>2012-06-01</p> <p>Trajectory planning for satellite formation flying missions requires the ability to find the <span class="hlt">optimal</span> control law to transfer a satellite from one periodic relative orbit to another. This article modifies Jezewski's linear impulsive trajectory <span class="hlt">optimization</span> method for solving nonlinear problems described in the relative coordinate frame, and proposes the concept of standard problems for the initialization of the <span class="hlt">optimizer</span>. With this modified <span class="hlt">optimizer</span> and the standard problem concept, the article studies the impulse number, the cost, and the nonlinearity of fixed-time coplanar transfer problems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008EnOp...40..869S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008EnOp...40..869S"><span id="translatedtitle">Computational fluid <span class="hlt">dynamics</span> and interactive multiobjective <span class="hlt">optimization</span> in the development of low-emission industrial boilers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Saario, A.; Oksanen, A.</p> <p>2008-09-01</p> <p>A CFD-based model is applied to study emission formation in a bubbling fluidized bed boiler burning biomass. After the model is validated to a certain extent, it is used for <span class="hlt">optimization</span>. There are nine design variables (nine distinct NH3 injections in the selective non-catalytic reduction process) and two objective functions (which minimize NO and NH3 emissions in flue gas). The multiobjective <span class="hlt">optimization</span> problem is solved using the reference-point method involving an achievement scalarizing function. The interactive reference-point method is applied to generate Pareto <span class="hlt">optimal</span> solutions. Two inherently different <span class="hlt">optimization</span> algorithms, viz. a genetic algorithm and Powell's conjugate-direction method, are applied in the solution of the resulting <span class="hlt">optimization</span> problem. It is shown that <span class="hlt">optimization</span> connected with CFD is a promising design tool for combustion <span class="hlt">optimization</span>. The strengths and weaknesses of the proposed approach and of the methods applied are discussed from the point of view of a complex real-world <span class="hlt">optimization</span> problem.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=taiwan&pg=3&id=EJ1040367','ERIC'); return false;" href="http://eric.ed.gov/?q=taiwan&pg=3&id=EJ1040367"><span id="translatedtitle">Academic <span class="hlt">Optimism</span> and Collective Responsibility: An Organizational Model of the <span class="hlt">Dynamics</span> of Student Achievement</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Wu, Jason H.</p> <p>2013-01-01</p> <p>This study was designed to examine the construct of academic <span class="hlt">optimism</span> and its relationship with collective responsibility in a sample of Taiwan elementary schools. The construct of academic <span class="hlt">optimism</span> was tested using confirmatory factor analysis, and the whole structural model was tested with a structural equation modeling analysis. The data were…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25746437','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25746437"><span id="translatedtitle">An accurate metalloprotein-specific scoring function and molecular docking program devised by a <span class="hlt">dynamic</span> sampling and iteration <span class="hlt">optimization</span> strategy.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bai, Fang; Liao, Sha; Gu, Junfeng; Jiang, Hualiang; Wang, Xicheng; Li, Honglin</p> <p>2015-04-27</p> <p>Metalloproteins, particularly zinc metalloproteins, are promising therapeutic targets, and recent efforts have focused on the identification of potent and selective inhibitors of these proteins. However, the ability of current drug discovery and design technologies, such as molecular docking and molecular <span class="hlt">dynamics</span> simulations, to probe metal-ligand interactions remains limited because of their complicated coordination geometries and rough treatment in current force fields. Herein we introduce a robust, multiobjective <span class="hlt">optimization</span> algorithm-driven metalloprotein-specific docking program named MpSDock, which runs on a scheme similar to consensus scoring consisting of a force-field-based scoring function and a knowledge-based scoring function. For this purpose, in this study, an effective knowledge-based zinc metalloprotein-specific scoring function based on the inverse Boltzmann law was designed and <span class="hlt">optimized</span> using a <span class="hlt">dynamic</span> sampling and iteration <span class="hlt">optimization</span> strategy. This <span class="hlt">optimization</span> strategy can <span class="hlt">dynamically</span> sample and regenerate decoy poses used in each iteration step of refining the scoring function, thus dramatically improving both the effectiveness of the exploration of the binding conformational space and the sensitivity of the ranking of the native binding poses. To validate the zinc metalloprotein-specific scoring function and its special built-in docking program, denoted MpSDockZn, an extensive comparison was performed against six universal, popular docking programs: Glide XP mode, Glide SP mode, Gold, AutoDock, AutoDock4Zn, and EADock DSS. The zinc metalloprotein-specific knowledge-based scoring function exhibited prominent performance in accurately describing the geometries and interactions of the coordination bonds between the zinc ions and chelating agents of the ligands. In addition, MpSDockZn had a competitive ability to sample and identify native binding poses with a higher success rate than the other six docking programs. PMID:25746437</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012MSSP...29...34S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012MSSP...29...34S"><span id="translatedtitle">Robust design <span class="hlt">optimization</span> of the vibrating rotor-shaft system subjected to selected <span class="hlt">dynamic</span> constraints</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stocki, R.; Szolc, T.; Tauzowski, P.; Knabel, J.</p> <p>2012-05-01</p> <p>The commonly observed nowadays tendency to weight minimization of rotor-shafts of the rotating machinery leads to a decrease of shaft bending rigidity making a risk of dangerous stress concentrations and rubbing effects more probable. Thus, a determination of the <span class="hlt">optimal</span> balance between reducing the rotor-shaft weight and assuring its admissible bending flexibility is a major goal of this study. The random nature of residual unbalances of the rotor-shaft as well as randomness of journal-bearing stiffness have been taken into account in the framework of robust design <span class="hlt">optimization</span>. Such a formulation of the <span class="hlt">optimization</span> problem leads to the <span class="hlt">optimal</span> design that combines an acceptable structural weight with the robustness with respect to uncertainties of residual unbalances - the main source of bending vibrations causing the rubbing effects. The applied robust <span class="hlt">optimization</span> technique is based on using Latin hypercubes in scatter analysis of the vibration response. The so-called <span class="hlt">optimal</span> Latin hypercubes are used as experimental plans for building kriging approximations of the objective and constraint functions. The proposed method has been applied for the <span class="hlt">optimization</span> of the typical single-span rotor-shaft of the 8-stage centrifugal compressor.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21217170','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21217170"><span id="translatedtitle">On the <span class="hlt">optimal</span> design of the disassembly and recovery processes</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Xanthopoulos, A.; Iakovou, E.</p> <p>2009-05-15</p> <p>This paper tackles the problem of the <span class="hlt">optimal</span> design of the recovery processes of the end-of-life (EOL) electric and electronic products, with a special focus on the disassembly issues. The objective is to recover as much ecological and economic value as possible, and to reduce the overall produced quantities of waste. In this context, a medium-range tactical problem is defined and a novel two-phased algorithm is presented for a remanufacturing-driven reverse supply chain. In the first phase, we propose a multicriteria/goal-programming analysis for the identification and the <span class="hlt">optimal</span> selection of the most 'desirable' subassemblies and components to be disassembled for recovery, from a set of different types of EOL products. In the second phase, a multi-product, multi-period <span class="hlt">mixed-integer</span> linear programming (MILP) model is presented, which addresses the <span class="hlt">optimization</span> of the recovery processes, while taking into account explicitly the lead times of the disassembly and recovery processes. Moreover, a simulation-based solution approach is proposed for capturing the uncertainties in reverse logistics. The overall approach leads to an easy-to-use methodology that could support effectively middle level management decisions. Finally, the applicability of the developed methodology is illustrated by its application on a specific case study.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24035245','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24035245"><span id="translatedtitle"><span class="hlt">Optimal</span> planning for the sustainable utilization of municipal solid waste.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Santibañez-Aguilar, José Ezequiel; Ponce-Ortega, José María; Betzabe González-Campos, J; Serna-González, Medardo; El-Halwagi, Mahmoud M</p> <p>2013-12-01</p> <p>The increasing generation of municipal solid waste (MSW) is a major problem particularly for large urban areas with insufficient landfill capacities and inefficient waste management systems. Several options associated to the supply chain for implementing a MSW management system are available, however to determine the <span class="hlt">optimal</span> solution several technical, economic, environmental and social aspects must be considered. Therefore, this paper proposes a mathematical programming model for the <span class="hlt">optimal</span> planning of the supply chain associated to the MSW management system to maximize the economic benefit while accounting for technical and environmental issues. The <span class="hlt">optimization</span> model simultaneously selects the processing technologies and their location, the distribution of wastes from cities as well as the distribution of products to markets. The problem was formulated as a multi-objective <span class="hlt">mixed-integer</span> linear programing problem to maximize the profit of the supply chain and the amount of recycled wastes, where the results are showed through Pareto curves that tradeoff economic and environmental aspects. The proposed approach is applied to a case study for the west-central part of Mexico to consider the integration of MSW from several cities to yield useful products. The results show that an integrated utilization of MSW can provide economic, environmental and social benefits. PMID:24035245</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/990958','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/990958"><span id="translatedtitle">Robust <span class="hlt">optimization</span> of contaminant sensor placement for community water systems.</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Konjevod, Goran; Carr, Robert D.; Greenberg, Harvey J.; Hart, William Eugene; Morrison, Tod; Phillips, Cynthia Ann; Lin, Henry; Lauer, Erik</p> <p>2004-09-01</p> <p>We present a series of related robust <span class="hlt">optimization</span> models for placing sensors in municipal water networks to detect contaminants that are maliciously or accidentally injected.We formulate sensor placement problems as <span class="hlt">mixed-integer</span> programs, for which the objective coefficients are not known with certainty. We consider a restricted absolute robustness criteria that is motivated by natural restrictions on the uncertain data, and we define three robust <span class="hlt">optimization</span> models that differ in how the coefficients in the objective vary. Under one set of assumptions there exists a sensor placement that is <span class="hlt">optimal</span> for all admissible realizations of the coefficients. Under other assumptions, we can apply sorting to solve each worst-case realization efficiently, or we can apply duality to integrate the worst-case outcome and have one integer program. The most difficult case is where the objective parameters are bilinear, and we prove its complexity is NP-hard even under simplifying assumptions. We consider a relaxation that provides an approximation, giving an overall guarantee of nearoptimality when used with branch-and-bound search. We present preliminary computational experiments that illustrate the computational complexity of solving these robust formulations on sensor placement applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24350473','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24350473"><span id="translatedtitle"><span class="hlt">Optimal</span> design of ethanol supply chains considering carbon trading effects and multiple technologies for side-product exploitation.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ortiz-Gutiérrez, R A; Giarola, S; Bezzo, F</p> <p>2013-01-01</p> <p>This work proposes a spatially explicit <span class="hlt">mixed</span> <span class="hlt">integer</span> linear programming modelling framework representing the <span class="hlt">dynamic</span> evolution of a bioethanol supply chain (SC) under increasing biofuel demand and greenhouse gas (GHG) emission savings over time. Key features of the proposed framework comprise: (i) the incorporation of available set-aside rural surfaces for energy crop cultivation; (ii) the acknowledgement ofan economic value to the overall GHG emissions through the introduction of an Emission Trading System. Multiple technological options are assessed to exploit the co-product Distiller's Dried Grains with Solubles either as animal fodder (standard usage) or as fuel for heat and power generation or as raw material for biogas production (and hence heat and power). Bioethanol production in Northern Italy is chosen as a demonstrative case study. PMID:24350473</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012E%26ES...15c2025K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012E%26ES...15c2025K"><span id="translatedtitle">Design <span class="hlt">optimization</span> of a centrifugal pump impeller and volute using computational fluid <span class="hlt">dynamics</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kim, J. H.; Oh, K. T.; Pyun, K. B.; Kim, C. K.; Choi, Y. S.; Yoon, J. Y.</p> <p>2012-11-01</p> <p>In this study, <span class="hlt">optimization</span> of the impeller and design of volute were carried out in order to improve the performance of a centrifugal pump. Design parameters from vane plane development for impeller design were selected and effect of the design parameters on the performance of the pump was analyzed using CFD and Response Surface Method to <span class="hlt">optimized</span> impeller. This study also proposed the <span class="hlt">optimization</span> geometry of pump impeller for performance improvement through the results from numerical analysis that was obtained optimum design pump; efficiency 98.2% and head 64.5m. In addition, the pump design method was suggested by designing volute which was suitable for the <span class="hlt">optimized</span> impeller through volute design where Stepanoff theory was applied and numerical analysis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005PhDT........41N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005PhDT........41N"><span id="translatedtitle"><span class="hlt">Optimal</span> control of a hyperbolic model of flow recirculation in a wind tunnel with <span class="hlt">dynamically</span> constrained boundary controls</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nguyen, Nhan T.</p> <p></p> <p>This thesis develops a new <span class="hlt">optimal</span> control theory for a class of distributed-parameter systems governed by first-order quasilinear hyperbolic partial differential equations that arise in many physical applications such as fluid <span class="hlt">dynamics</span> problems. These systems are controlled at their boundaries via boundary controls that are subject to <span class="hlt">dynamic</span> constraints imposed by lumped-parameter systems governed by ordinary differential equations. A Mach number control problem for a closed-circuit wind tunnel is investigated. The flow is modeled using the Euler equations and is controlled by a compressor performance model defined as two-point boundary conditions. The boundary control inputs to the compressor are in turn controlled by two first-order lumped-parameter systems that represent <span class="hlt">dynam