A Polynomial-Time Algorithm for Optimizing over N-Fold 4-Block Decomposable Integer Programs
NASA Astrophysics Data System (ADS)
Hemmecke, Raymond; Köppe, Matthias; Weismantel, Robert
In this paper we generalize N-fold integer programs and two-stage integer programs with N scenarios to N-fold 4-block decomposable integer programs. We show that for fixed blocks but variable N, these integer programs are polynomial-time solvable for any linear objective. Moreover, we present a polynomial-time computable optimality certificate for the case of fixed blocks, variable N and any convex separable objective function. We conclude with two sample applications, stochastic integer programs with second-order dominance constraints and stochastic integer multi-commodity flows, which (for fixed blocks) can be solved in polynomial time in the number of scenarios and commodities and in the binary encoding length of the input data. In the proof of our main theorem we combine several non-trivial constructions from the theory of Graver bases. We are confident that our approach paves the way for further extensions.
Logic integer programming models for signaling networks.
Haus, Utz-Uwe; Niermann, Kathrin; Truemper, Klaus; Weismantel, Robert
2009-05-01
We propose a static and a dynamic approach to model biological signaling networks, and show how each can be used to answer relevant biological questions. For this, we use the two different mathematical tools of Propositional Logic and Integer Programming. The power of discrete mathematics for handling qualitative as well as quantitative data has so far not been exploited in molecular biology, which is mostly driven by experimental research, relying on first-order or statistical models. The arising logic statements and integer programs are analyzed and can be solved with standard software. For a restricted class of problems the logic models reduce to a polynomial-time solvable satisfiability algorithm. Additionally, a more dynamic model enables enumeration of possible time resolutions in poly-logarithmic time. Computational experiments are included.
Hybrid Biogeography-Based Optimization for Integer Programming
Wang, Zhi-Cheng
2014-01-01
Biogeography-based optimization (BBO) is a relatively new bioinspired heuristic for global optimization based on the mathematical models of biogeography. By investigating the applicability and performance of BBO for integer programming, we find that the original BBO algorithm does not perform well on a set of benchmark integer programming problems. Thus we modify the mutation operator and/or the neighborhood structure of the algorithm, resulting in three new BBO-based methods, named BlendBBO, BBO_DE, and LBBO_LDE, respectively. Computational experiments show that these methods are competitive approaches to solve integer programming problems, and the LBBO_LDE shows the best performance on the benchmark problems. PMID:25003142
Program Helps Decompose Complicated Design Problems
NASA Technical Reports Server (NTRS)
Rogers, James L., Jr.
1993-01-01
Time saved by intelligent decomposition into smaller, interrelated problems. DeMAID is knowledge-based software system for ordering sequence of modules and identifying possible multilevel structure for design problem. Displays modules in N x N matrix format. Requires investment of time to generate and refine list of modules for input, it saves considerable amount of money and time in total design process, particularly new design problems in which ordering of modules has not been defined. Program also implemented to examine assembly-line process or ordering of tasks and milestones.
Currency Arbitrage Detection Using a Binary Integer Programming Model
ERIC Educational Resources Information Center
Soon, Wanmei; Ye, Heng-Qing
2011-01-01
In this article, we examine the use of a new binary integer programming (BIP) model to detect arbitrage opportunities in currency exchanges. This model showcases an excellent application of mathematics to the real world. The concepts involved are easily accessible to undergraduate students with basic knowledge in Operations Research. Through this…
Optimizing a Library's Loan Policy: An Integer Programming Approach.
ERIC Educational Resources Information Center
Al-Fares, Hesham K.
1998-01-01
Discusses the length of library loan periods and the number of books allowed to be borrowed. An integer programming model is formulated whose solution yields the optimum user satisfaction, and a case study conducted at King Fahd University of Petroleum and Minerals (Saudi Arabia) is presented. (Author/LRW)
Investigating Integer Restrictions in Linear Programming
ERIC Educational Resources Information Center
Edwards, Thomas G.; Chelst, Kenneth R.; Principato, Angela M.; Wilhelm, Thad L.
2015-01-01
Linear programming (LP) is an application of graphing linear systems that appears in many Algebra 2 textbooks. Although not explicitly mentioned in the Common Core State Standards for Mathematics, linear programming blends seamlessly into modeling with mathematics, the fourth Standard for Mathematical Practice (CCSSI 2010, p. 7). In solving a…
Currency arbitrage detection using a binary integer programming model
NASA Astrophysics Data System (ADS)
Soon, Wanmei; Ye, Heng-Qing
2011-04-01
In this article, we examine the use of a new binary integer programming (BIP) model to detect arbitrage opportunities in currency exchanges. This model showcases an excellent application of mathematics to the real world. The concepts involved are easily accessible to undergraduate students with basic knowledge in Operations Research. Through this work, students can learn to link several types of basic optimization models, namely linear programming, integer programming and network models, and apply the well-known sensitivity analysis procedure to accommodate realistic changes in the exchange rates. Beginning with a BIP model, we discuss how it can be reduced to an equivalent but considerably simpler model, where an efficient algorithm can be applied to find the arbitrages and incorporate the sensitivity analysis procedure. A simple comparison is then made with a different arbitrage detection model. This exercise helps students learn to apply basic Operations Research concepts to a practical real-life example, and provides insights into the processes involved in Operations Research model formulations.
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.
Split diversity in constrained conservation prioritization using integer linear programming
Chernomor, Olga; Minh, Bui Quang; Forest, Félix; Klaere, Steffen; Ingram, Travis; Henzinger, Monika; von Haeseler, Arndt
2015-01-01
Phylogenetic diversity (PD) is a measure of biodiversity based on the evolutionary history of species. Here, we discuss several optimization problems related to the use of PD, and the more general measure split diversity (SD), in conservation prioritization. Depending on the conservation goal and the information available about species, one can construct optimization routines that incorporate various conservation constraints. We demonstrate how this information can be used to select sets of species for conservation action. Specifically, we discuss the use of species' geographic distributions, the choice of candidates under economic pressure, and the use of predator–prey interactions between the species in a community to define viability constraints. Despite such optimization problems falling into the area of NP hard problems, it is possible to solve them in a reasonable amount of time using integer programming. We apply integer linear programming to a variety of models for conservation prioritization that incorporate the SD measure. We exemplarily show the results for two data sets: the Cape region of South Africa and a Caribbean coral reef community. Finally, we provide user-friendly software at http://www.cibiv.at/software/pda. PMID:25893087
Diet planning for humans using mixed-integer linear programming.
Sklan, D; Dariel, I
1993-07-01
Human diet planning is generally carried out by selecting the food items or groups of food items to be used in the diet and then calculating the composition. If nutrient quantities do not reach the desired nutritional requirements, foods are exchanged or quantities altered and the composition recalculated. Iterations are repeated until a suitable diet is obtained. This procedure is cumbersome and slow and often leads to compromises in composition of the final diets. A computerized model, planning diets for humans at minimum cost while supplying all nutritional requirements, maintaining nutrient relationships and preserving eating practices is presented. This is based on a mixed-integer linear-programming algorithm. Linear equations were prepared for each nutritional requirement. To produce linear equations for relationships between nutrients, linear transformations were performed. Logical definitions for interactions such as the frequency of use of foods, relationships between exchange groups and the energy content of different meals were defined, and linear equations for these associations were written. Food items generally eaten in whole units were defined as integers. The use of this program is demonstrated for planning diets using a large selection of basic foods and for clinical situations where nutritional intervention is desirable. The system presented begins from a definition of the nutritional requirements and then plans the foods accordingly, and at minimum cost. This provides an accurate, efficient and versatile method of diet formulation.
Ellrott, Kyle; Guo, Jun-tao; Olman, Victor; Xu, Ying
2006-01-01
Integer programming is a combinatorial optimization method that has been successfully applied to the protein threading problem. We seek to expand the model optimized by this technique to allow for a more accurate description of protein threading. We have developed and implemented an expanded model of integer programming that has the capability to model secondary structure element deletion, which was not possible in previous version of integer programming based optimization. PMID:17503397
Reconstructing cerebrovascular networks under local physiological constraints by integer programming
Rempfler, Markus; Schneider, Matthias; Ielacqua, Giovanna D.; Xiao, Xianghui; Stock, Stuart R.; Klohs, Jan; Szekely, Gabor; Andres, Bjoern; Menze, Bjoern H.
2015-04-23
We introduce a probabilistic approach to vessel network extraction that enforces physiological constraints on the vessel structure. The method accounts for both image evidence and geometric relationships between vessels by solving an integer program, which is shown to yield the maximum a posteriori (MAP) estimate to the probabilistic model. Starting from an over-connected network, it is pruning vessel stumps and spurious connections by evaluating the local geometry and the global connectivity of the graph. We utilize a high-resolution micro computed tomography (µCT) dataset of a cerebrovascular corrosion cast to obtain a reference network and learn the prior distributions of ourmore » probabilistic model. As a result, we perform experiments on micro magnetic resonance angiography (µMRA) images of mouse brains and discuss properties of the networks obtained under different tracking and pruning approaches.« less
Reconstructing cerebrovascular networks under local physiological constraints by integer programming
Rempfler, Markus; Schneider, Matthias; Ielacqua, Giovanna D.; Xiao, Xianghui; Stock, Stuart R.; Klohs, Jan; Szekely, Gabor; Andres, Bjoern; Menze, Bjoern H.
2015-04-23
We introduce a probabilistic approach to vessel network extraction that enforces physiological constraints on the vessel structure. The method accounts for both image evidence and geometric relationships between vessels by solving an integer program, which is shown to yield the maximum a posteriori (MAP) estimate to the probabilistic model. Starting from an over-connected network, it is pruning vessel stumps and spurious connections by evaluating the local geometry and the global connectivity of the graph. We utilize a high-resolution micro computed tomography (µCT) dataset of a cerebrovascular corrosion cast to obtain a reference network and learn the prior distributions of our probabilistic model. As a result, we perform experiments on micro magnetic resonance angiography (µMRA) images of mouse brains and discuss properties of the networks obtained under different tracking and pruning approaches.
Validation and assessment of integer programming sensor placement models.
Uber, James G.; Hart, William Eugene; Watson, Jean-Paul; Phillips, Cynthia Ann; Berry, Jonathan W.
2005-02-01
We consider the accuracy of predictions made by integer programming (IP) models of sensor placement for water security applications. We have recently shown that IP models can be used to find optimal sensor placements for a variety of different performance criteria (e.g. minimize health impacts and minimize time to detection). However, these models make a variety of simplifying assumptions that might bias the final solution. We show that our IP modeling assumptions are similar to models developed for other sensor placement methodologies, and thus IP models should give similar predictions. However, this discussion highlights that there are significant differences in how temporal effects are modeled for sensor placement. We describe how these modeling assumptions can impact sensor placements.
Rempfler, Markus; Schneider, Matthias; Ielacqua, Giovanna D; Xiao, Xianghui; Stock, Stuart R; Klohs, Jan; Székely, Gábor; Andres, Bjoern; Menze, Bjoern H
2015-10-01
We introduce a probabilistic approach to vessel network extraction that enforces physiological constraints on the vessel structure. The method accounts for both image evidence and geometric relationships between vessels by solving an integer program, which is shown to yield the maximum a posteriori (MAP) estimate to a probabilistic model. Starting from an overconnected network, it is pruning vessel stumps and spurious connections by evaluating the local geometry and the global connectivity of the graph. We utilize a high-resolution micro computed tomography (μCT) dataset of a cerebrovascular corrosion cast to obtain a reference network and learn the prior distributions of our probabilistic model and we perform experiments on in-vivo magnetic resonance microangiography (μMRA) images of mouse brains. We finally discuss properties of the networks obtained under different tracking and pruning approaches.
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.
A cost-aggregating integer linear program for motif finding.
Kingsford, Carl; Zaslavsky, Elena; Singh, Mona
2011-12-01
In the motif finding problem one seeks a set of mutually similar substrings within a collection of biological sequences. This is an important and widely-studied problem, as such shared motifs in DNA often correspond to regulatory elements. We study a combinatorial framework where the goal is to find substrings of a given length such that the sum of their pairwise distances is minimized. We describe a novel integer linear program for the problem, which uses the fact that distances between substrings come from a limited set of possibilities allowing for aggregate consideration of sequence position pairs with the same distances. We show how to tighten its linear programming relaxation by adding an exponential set of constraints and give an efficient separation algorithm that can find violated constraints, thereby showing that the tightened linear program can still be solved in polynomial time. We apply our approach to find optimal solutions for the motif finding problem and show that it is effective in practice in uncovering known transcription factor binding sites.
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…
Constrained spacecraft reorientation using mixed integer convex programming
NASA Astrophysics Data System (ADS)
Tam, Margaret; Glenn Lightsey, E.
2016-10-01
A constrained attitude guidance (CAG) system is developed using convex optimization to autonomously achieve spacecraft pointing objectives while meeting the constraints imposed by on-board hardware. These constraints include bounds on the control input and slew rate, as well as pointing constraints imposed by the sensors. The pointing constraints consist of inclusion and exclusion cones that dictate permissible orientations of the spacecraft in order to keep objects in or out of the field of view of the sensors. The optimization scheme drives a body vector towards a target inertial vector along a trajectory that consists solely of permissible orientations in order to achieve the desired attitude for a given mission mode. The non-convex rotational kinematics are handled by discretization, which also ensures that the quaternion stays unity norm. In order to guarantee an admissible path, the pointing constraints are relaxed. Depending on how strict the pointing constraints are, the degree of relaxation is tuneable. The use of binary variables permits the inclusion of logical expressions in the pointing constraints in the case that a set of sensors has redundancies. The resulting mixed integer convex programming (MICP) formulation generates a steering law that can be easily integrated into an attitude determination and control (ADC) system. A sample simulation of the system is performed for the Bevo-2 satellite, including disturbance torques and actuator dynamics which are not modeled by the controller. Simulation results demonstrate the robustness of the system to disturbances while meeting the mission requirements with desirable performance characteristics.
Accurate construction of consensus genetic maps via integer linear programming.
Wu, Yonghui; Close, Timothy J; Lonardi, Stefano
2011-01-01
We study the problem of merging genetic maps, when the individual genetic maps are given as directed acyclic graphs. The computational problem is to build a consensus map, which is a directed graph that includes and is consistent with all (or, the vast majority of) the markers in the input maps. However, when markers in the individual maps have ordering conflicts, the resulting consensus map will contain cycles. Here, we formulate the problem of resolving cycles in the context of a parsimonious paradigm that takes into account two types of errors that may be present in the input maps, namely, local reshuffles and global displacements. The resulting combinatorial optimization problem is, in turn, expressed as an integer linear program. A fast approximation algorithm is proposed, and an additional speedup heuristic is developed. Our algorithms were implemented in a software tool named MERGEMAP which is freely available for academic use. An extensive set of experiments shows that MERGEMAP consistently outperforms JOINMAP, which is the most popular tool currently available for this task, both in terms of accuracy and running time. MERGEMAP is available for download at http://www.cs.ucr.edu/~yonghui/mgmap.html. PMID:20479505
An integer programming approach to DNA sequence assembly.
Chang, Youngjung; Sahinidis, Nikolaos V
2011-08-10
De novo sequence assembly is a ubiquitous combinatorial problem in all DNA sequencing technologies. In the presence of errors in the experimental data, the assembly problem is computationally challenging, and its solution may not lead to a unique reconstruct. The enumeration of all alternative solutions is important in drawing a reliable conclusion on the target sequence, and is often overlooked in the heuristic approaches that are currently available. In this paper, we develop an integer programming formulation and global optimization solution strategy to solve the sequence assembly problem with errors in the data. We also propose an efficient technique to identify all alternative reconstructs. When applied to examples of sequencing-by-hybridization, our approach dramatically increases the length of DNA sequences that can be handled with global optimality certificate to over 10,000, which is more than 10 times longer than previously reported. For some problem instances, alternative solutions exhibited a wide range of different ability in reproducing the target DNA sequence. Therefore, it is important to utilize the methodology proposed in this paper in order to obtain all alternative solutions to reliably infer the true reconstruct. These alternative solutions can be used to refine the obtained results and guide the design of further experiments to correctly reconstruct the target DNA sequence. PMID:21864794
Accurate construction of consensus genetic maps via integer linear programming.
Wu, Yonghui; Close, Timothy J; Lonardi, Stefano
2011-01-01
We study the problem of merging genetic maps, when the individual genetic maps are given as directed acyclic graphs. The computational problem is to build a consensus map, which is a directed graph that includes and is consistent with all (or, the vast majority of) the markers in the input maps. However, when markers in the individual maps have ordering conflicts, the resulting consensus map will contain cycles. Here, we formulate the problem of resolving cycles in the context of a parsimonious paradigm that takes into account two types of errors that may be present in the input maps, namely, local reshuffles and global displacements. The resulting combinatorial optimization problem is, in turn, expressed as an integer linear program. A fast approximation algorithm is proposed, and an additional speedup heuristic is developed. Our algorithms were implemented in a software tool named MERGEMAP which is freely available for academic use. An extensive set of experiments shows that MERGEMAP consistently outperforms JOINMAP, which is the most popular tool currently available for this task, both in terms of accuracy and running time. MERGEMAP is available for download at http://www.cs.ucr.edu/~yonghui/mgmap.html.
Learning oncogenetic networks by reducing to mixed integer linear programming.
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.
Fish Processed Production Planning Using Integer Stochastic Programming Model
NASA Astrophysics Data System (ADS)
Firmansyah, Mawengkang, Herman
2011-06-01
Fish and its processed products are the most affordable source of animal protein in the diet of most people in Indonesia. The goal in production planning is to meet customer demand over a fixed time horizon divided into planning periods by optimizing the trade-off between economic objectives such as production cost and customer satisfaction level. The major decisions are production and inventory levels for each product and the number of workforce in each planning period. In this paper we consider the management of small scale traditional business at North Sumatera Province which performs processing fish into several local seafood products. The inherent uncertainty of data (e.g. demand, fish availability), together with the sequential evolution of data over time leads the production planning problem to a nonlinear mixed-integer stochastic programming model. We use scenario generation based approach and feasible neighborhood search for solving the model. The results which show the amount of each fish processed product and the number of workforce needed in each horizon planning are presented.
Mixed integer linear programming for maximum-parsimony phylogeny inference.
Sridhar, Srinath; Lam, Fumei; Blelloch, Guy E; Ravi, R; Schwartz, Russell
2008-01-01
Reconstruction of phylogenetic trees is a fundamental problem in computational biology. While excellent heuristic methods are available for many variants of this problem, new advances in phylogeny inference will be required if we are to be able to continue to make effective use of the rapidly growing stores of variation data now being gathered. In this paper, we present two integer linear programming (ILP) formulations to find the most parsimonious phylogenetic tree from a set of binary variation data. One method uses a flow-based formulation that can produce exponential numbers of variables and constraints in the worst case. The method has, however, proven extremely efficient in practice on datasets that are well beyond the reach of the available provably efficient methods, solving several large mtDNA and Y-chromosome instances within a few seconds and giving provably optimal results in times competitive with fast heuristics than cannot guarantee optimality. An alternative formulation establishes that the problem can be solved with a polynomial-sized ILP. We further present a web server developed based on the exponential-sized ILP that performs fast maximum parsimony inferences and serves as a front end to a database of precomputed phylogenies spanning the human genome.
IESIP - AN IMPROVED EXPLORATORY SEARCH TECHNIQUE FOR PURE INTEGER LINEAR PROGRAMMING PROBLEMS
NASA Technical Reports Server (NTRS)
Fogle, F. R.
1994-01-01
IESIP, an Improved Exploratory Search Technique for Pure Integer Linear Programming Problems, addresses the problem of optimizing an objective function of one or more variables subject to a set of confining functions or constraints by a method called discrete optimization or integer programming. Integer programming is based on a specific form of the general linear programming problem in which all variables in the objective function and all variables in the constraints are integers. While more difficult, integer programming is required for accuracy when modeling systems with small numbers of components such as the distribution of goods, machine scheduling, and production scheduling. IESIP establishes a new methodology for solving pure integer programming problems by utilizing a modified version of the univariate exploratory move developed by Robert Hooke and T.A. Jeeves. IESIP also takes some of its technique from the greedy procedure and the idea of unit neighborhoods. A rounding scheme uses the continuous solution found by traditional methods (simplex or other suitable technique) and creates a feasible integer starting point. The Hook and Jeeves exploratory search is modified to accommodate integers and constraints and is then employed to determine an optimal integer solution from the feasible starting solution. The user-friendly IESIP allows for rapid solution of problems up to 10 variables in size (limited by DOS allocation). Sample problems compare IESIP solutions with the traditional branch-and-bound approach. IESIP is written in Borland's TURBO Pascal for IBM PC series computers and compatibles running DOS. Source code and an executable are provided. The main memory requirement for execution is 25K. This program is available on a 5.25 inch 360K MS DOS format diskette. IESIP was developed in 1990. IBM is a trademark of International Business Machines. TURBO Pascal is registered by Borland International.
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
McConnel, M B; Galligan, D T
2004-10-01
Optimization programs are currently used to aid in the selection of bulls to be used in herd breeding programs. While these programs offer a systematic approach to the problem of semen selection, they ignore the impact of volume discounts. Volume discounts are discounts that vary depending on the number of straws purchased. The dynamic nature of volume discounts means that, in order to be adequately accounted for, they must be considered in the optimization routine. Failing to do this creates a missed economic opportunity because the potential benefits of optimally selecting and combining breeding company discount opportunities are not captured. To address these issues, an integer program was created which used binary decision variables to incorporate the effects of quantity discounts into the optimization program. A consistent set of trait criteria was used to select a group of bulls from 3 sample breeding companies. Three different selection programs were used to select the bulls, 2 traditional methods and the integer method. After the discounts were applied using each method, the integer program resulted in the lowest cost portfolio of bulls. A sensitivity analysis showed that the integer program also resulted in a low cost portfolio when the genetic trait goals were changed to be more or less stringent. In the sample application, a net benefit of the new approach over the traditional approaches was a 12.3 to 20.0% savings in semen cost. PMID:15377634
Solution of Mixed-Integer Programming Problems on the XT5
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.
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.
Li, Yongping; Huang, Guohe
2009-03-01
In this study, a dynamic analysis approach based on an inexact multistage integer programming (IMIP) model is developed for supporting municipal solid waste (MSW) management under uncertainty. Techniques of interval-parameter programming and multistage stochastic programming are incorporated within an integer-programming framework. The developed IMIP can deal with uncertainties expressed as probability distributions and interval numbers, and can reflect the dynamics in terms of decisions for waste-flow allocation and facility-capacity expansion over a multistage context. Moreover, the IMIP can be used for analyzing various policy scenarios that are associated with different levels of economic consequences. The developed method is applied to a case study of long-term waste-management planning. The results indicate that reasonable solutions have been generated for binary and continuous variables. They can help generate desired decisions of system-capacity expansion and waste-flow allocation with a minimized system cost and maximized system reliability. PMID:19320267
NASA Astrophysics Data System (ADS)
Khan, Sahubar Ali Bin Mohamed Nadhar; Ahmarofi, Ahmad Afif Bin
2014-12-01
In manufacturing sector, production planning or scheduling is the most important managerial task in order to achieve profit maximization and cost minimization. With limited resources, the management has to satisfy customer demand and at the same time fulfill company's objective, which is to maximize profit or minimize cost. Hence, planning becomes a significant task for production site in order to determine optimal number of units for each product to be produced. In this study, integer programming technique is used to develop an appropriate product-mix planning to obtain the optimal number of audio speaker products that should be produced in order to maximize profit. Branch-and-bound method is applied to obtain exact integer solutions when non-integer solutions occurred. Three major resource constraints are considered in this problem: raw materials constraint, demand constraint and standard production time constraint. It is found that, the developed integer programming model gives significant increase in profit compared to the existing method used by the company. At the end of the study, sensitivity analysis was performed to evaluate the effects of changes in objective function coefficient and available resources on the developed model. This will enable the management to foresee the effects on the results when some changes happen to the profit of its products or available resources.
Smart-Grid Backbone Network Real-Time Delay Reduction via Integer Programming.
Pagadrai, Sasikanth; Yilmaz, Muhittin; Valluri, Pratyush
2016-08-01
This research investigates an optimal delay-based virtual topology design using integer linear programming (ILP), which is applied to the current backbone networks such as smart-grid real-time communication systems. A network traffic matrix is applied and the corresponding virtual topology problem is solved using the ILP formulations that include a network delay-dependent objective function and lightpath routing, wavelength assignment, wavelength continuity, flow routing, and traffic loss constraints. The proposed optimization approach provides an efficient deterministic integration of intelligent sensing and decision making, and network learning features for superior smart grid operations by adaptively responding the time-varying network traffic data as well as operational constraints to maintain optimal virtual topologies. A representative optical backbone network has been utilized to demonstrate the proposed optimization framework whose simulation results indicate that superior smart-grid network performance can be achieved using commercial networks and integer programming.
Smart-Grid Backbone Network Real-Time Delay Reduction via Integer Programming.
Pagadrai, Sasikanth; Yilmaz, Muhittin; Valluri, Pratyush
2016-08-01
This research investigates an optimal delay-based virtual topology design using integer linear programming (ILP), which is applied to the current backbone networks such as smart-grid real-time communication systems. A network traffic matrix is applied and the corresponding virtual topology problem is solved using the ILP formulations that include a network delay-dependent objective function and lightpath routing, wavelength assignment, wavelength continuity, flow routing, and traffic loss constraints. The proposed optimization approach provides an efficient deterministic integration of intelligent sensing and decision making, and network learning features for superior smart grid operations by adaptively responding the time-varying network traffic data as well as operational constraints to maintain optimal virtual topologies. A representative optical backbone network has been utilized to demonstrate the proposed optimization framework whose simulation results indicate that superior smart-grid network performance can be achieved using commercial networks and integer programming. PMID:25935050
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.
Detection of code spread OFDM based on 0-1 integer quadratic programming
NASA Astrophysics Data System (ADS)
Elghariani, Ali; Zoltowski, Michael D.
2012-05-01
In this paper we introduce Integer Quadratic Programming (MIQP) approach to optimally detect QPSK Code Spread OFDM (CS-OFDM) by formulating the problem as a combinatorial optimization problem. The Branch and Bound (BB) algorithm is utilized to solve this integer quadratic programming problem. Furthermore, we propose combined preprocessing steps that can be applied prior to BB so that the computational complexity of the optimum receiver is reduced. The first step in this combination is to detect as much as possible symbols using procedures presented in [9], which is basically based on the gradient of quadratic function. The second step detects the undetected symbols from the first step using MMSE estimator. The result of the latter step will be used to predict the initial upper bound of the BB algorithm. Simulation results show that the proposed preprocessing combination when applied prior to BB provides optimal performance with a significantly reduced computational complexity.
Zörnig, Peter
2015-08-01
We present integer programming models for some variants of the farthest string problem. The number of variables and constraints is substantially less than that of the integer linear programming models known in the literature. Moreover, the solution of the linear programming-relaxation contains only a small proportion of noninteger values, which considerably simplifies the rounding process. Numerical tests have shown excellent results, especially when a small set of long sequences is given.
PySP : modeling and solving stochastic mixed-integer programs in Python.
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.
Obtaining lower bounds from the progressive hedging algorithm for stochastic mixed-integer programs
Gade, Dinakar; Hackebeil, Gabriel; Ryan, Sarah M.; Watson, Jean -Paul; Wets, Roger J.-B.; Woodruff, David L.
2016-04-02
We present a method for computing lower bounds in the progressive hedging algorithm (PHA) for two-stage and multi-stage stochastic mixed-integer programs. Computing lower bounds in the PHA allows one to assess the quality of the solutions generated by the algorithm contemporaneously. The lower bounds can be computed in any iteration of the algorithm by using dual prices that are calculated during execution of the standard PHA. In conclusion, we report computational results on stochastic unit commitment and stochastic server location problem instances, and explore the relationship between key PHA parameters and the quality of the resulting lower bounds.
Integration of progressive hedging and dual decomposition in stochastic integer programs
Watson, Jean -Paul; Guo, Ge; Hackebeil, Gabriel; Ryan, Sarah M.; Woodruff, David L.
2015-04-07
We present a method for integrating the Progressive Hedging (PH) algorithm and the Dual Decomposition (DD) algorithm of Carøe and Schultz for stochastic mixed-integer programs. Based on the correspondence between lower bounds obtained with PH and DD, a method to transform weights from PH to Lagrange multipliers in DD is found. Fast progress in early iterations of PH speeds up convergence of DD to an exact solution. As a result, we report computational results on server location and unit commitment instances.
An Integer Programming Formulation of the Minimum Common String Partition Problem.
Ferdous, S M; Rahman, M Sohel
2015-01-01
We consider the problem of finding a minimum common string partition (MCSP) of two strings, which is an NP-hard problem. The MCSP problem is closely related to genome comparison and rearrangement, an important field in Computational Biology. In this paper, we map the MCSP problem into a graph applying a prior technique and using this graph, we develop an Integer Linear Programming (ILP) formulation for the problem. We implement the ILP formulation and compare the results with the state-of-the-art algorithms from the literature. The experimental results are found to be promising.
Edit distance for marked point processes revisited: An implementation by binary integer programming
Hirata, Yoshito; Aihara, Kazuyuki
2015-12-15
We implement the edit distance for marked point processes [Suzuki et al., Int. J. Bifurcation Chaos 20, 3699–3708 (2010)] as a binary integer program. Compared with the previous implementation using minimum cost perfect matching, the proposed implementation has two advantages: first, by using the proposed implementation, we can apply a wide variety of software and hardware, even spin glasses and coherent ising machines, to calculate the edit distance for marked point processes; second, the proposed implementation runs faster than the previous implementation when the difference between the numbers of events in two time windows for a marked point process is large.
An Integer Programming Model for the Management of a Forest in the North of Portugal
NASA Astrophysics Data System (ADS)
Cerveira, Adelaide; Fonseca, Teresa; Mota, Artur; Martins, Isabel
2011-09-01
This study aims to develop an approach for the management of a forest of maritime pine located in the north region of Portugal. The forest is classified into five public lands, the so-called baldios, extending over 4432 ha. These baldios are co-managed by the Official Forest Services and the local communities mainly for timber production purposes. The forest planning involves non-spatial and spatial constraints. Spatial constraints dictate a maximum clearcut area and an exclusion time. An integer programming model is presented and the computational results are discussed.
Inexact multistage stochastic integer programming for water resources management under uncertainty.
Li, Y P; Huang, G H; Nie, S L; Liu, L
2008-07-01
In this study, an inexact multistage stochastic integer programming (IMSIP) method is developed for water resources management under uncertainty. This method incorporates techniques of inexact optimization and multistage stochastic programming within an integer programming framework. It can deal with uncertainties expressed as both probabilities and discrete intervals, and reflect the dynamics in terms of decisions for water allocation through transactions at discrete points of a complete scenario set over a multistage context. Moreover, the IMSIP can facilitate analyses of the multiple policy scenarios that are associated with economic penalties when the promised targets are violated as well as the economies-of-scale in the costs for surplus water diversion. A case study is provided for demonstrating the applicability of the developed methodology. The results indicate that reasonable solutions have been generated for both binary and continuous variables. For all scenarios under consideration, corrective actions can be undertaken dynamically under various pre-regulated policies and can thus help minimize the penalties and costs. The IMSIP can help water resources managers to identify desired system designs against water shortage and for flood control with maximized economic benefit and minimized system-failure risk. PMID:17532113
NASA Astrophysics Data System (ADS)
Huang, Kai; Huang, Gordon; Dai, Liming; Fan, Yurui
2016-08-01
This article introduces an inexact fuzzy integer chance constraint programming (IFICCP) approach for identifying noise reduction strategy under uncertainty. The IFICCP method integrates the interval programming and fuzzy chance constraint programming approaches into a framework, which is able to deal with uncertainties expressed as intervals and fuzziness. The proposed IFICCP model can be converted into two deterministic submodels corresponding to the optimistic and pessimistic conditions. The modelling approach is applied to a hypothetical control measure selection problem for noise reduction. Results of the case study indicate that useful solutions for noise control practices can be acquired. Three acceptable noise levels for two communities are considered. For each acceptable noise level, several decision alternatives have been obtained and analysed under different fuzzy confidence levels, which reflect the trade-offs between environmental and economic considerations.
Upper Bounds on the Number of Solutions of Binary Integer Programs
NASA Astrophysics Data System (ADS)
Jain, Siddhartha; Kadioglu, Serdar; Sellmann, Meinolf
We present a new method to compute upper bounds of the number of solutions of binary integer programming (BIP) problems. Given a BIP, we create a dynamic programming (DP) table for a redundant knapsack constraint which is obtained by surrogate relaxation. We then consider a Lagrangian relaxation of the original problem to obtain an initial weight bound on the knapsack. This bound is then refined through subgradient optimization. The latter provides a variety of Lagrange multipliers which allow us to filter infeasible edges in the DP table. The number of paths in the final table then provides an upper bound on the number of solutions. Numerical results show the effectiveness of our counting framework on automatic recording and market split problems.
An improved exploratory search technique for pure integer linear programming problems
NASA Technical Reports Server (NTRS)
Fogle, F. R.
1990-01-01
The development is documented of a heuristic method for the solution of pure integer linear programming problems. The procedure draws its methodology from the ideas of Hooke and Jeeves type 1 and 2 exploratory searches, greedy procedures, and neighborhood searches. It uses an efficient rounding method to obtain its first feasible integer point from the optimal continuous solution obtained via the simplex method. Since this method is based entirely on simple addition or subtraction of one to each variable of a point in n-space and the subsequent comparison of candidate solutions to a given set of constraints, it facilitates significant complexity improvements over existing techniques. It also obtains the same optimal solution found by the branch-and-bound technique in 44 of 45 small to moderate size test problems. Two example problems are worked in detail to show the inner workings of the method. Furthermore, using an established weighted scheme for comparing computational effort involved in an algorithm, a comparison of this algorithm is made to the more established and rigorous branch-and-bound method. A computer implementation of the procedure, in PC compatible Pascal, is also presented and discussed.
ERIC Educational Resources Information Center
Donoghue, John R.
2015-01-01
At the heart of van der Linden's approach to automated test assembly (ATA) is a linear programming/integer programming (LP/IP) problem. A variety of IP solvers are available, ranging in cost from free to hundreds of thousands of dollars. In this paper, I compare several approaches to solving the underlying IP problem. These approaches range from…
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.
NASA Technical Reports Server (NTRS)
Haftka, R. T.; Adelman, H. M.
1985-01-01
Orbiting spacecraft such as large space antennas have to maintain a highly accurate shape to operate satisfactorily. Such structures require active and passive controls to maintain an accurate shape under a variety of disturbances. Methods for the optimum placement of control actuators for correcting static deformations are described. In particular, attention is focused on the case were control locations have to be selected from a large set of available sites, so that integer programing methods are called for. The effectiveness of three heuristic techniques for obtaining a near-optimal site selection is compared. In addition, efficient reanalysis techniques for the rapid assessment of control effectiveness are presented. Two examples are used to demonstrate the methods: a simple beam structure and a 55m space-truss-parabolic antenna.
NASA Technical Reports Server (NTRS)
Haftka, R. T.; Adelman, H. M.
1984-01-01
Orbiting spacecraft such as large space antennas have to maintain a highly accurate space to operate satisfactorily. Such structures require active and passive controls to mantain an accurate shape under a variety of disturbances. Methods for the optimum placement of control actuators for correcting static deformations are described. In particular, attention is focused on the case were control locations have to be selected from a large set of available sites, so that integer programing methods are called for. The effectiveness of three heuristic techniques for obtaining a near-optimal site selection is compared. In addition, efficient reanalysis techniques for the rapid assessment of control effectiveness are presented. Two examples are used to demonstrate the methods: a simple beam structure and a 55m space-truss-parabolic antenna.
Optimization of a wood dryer kiln using the mixed integer programming technique: A case study
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.
An integer programming model for gate assignment problem at airline terminals
NASA Astrophysics Data System (ADS)
Chun, Chong Kok; Nordin, Syarifah Zyurina
2015-05-01
In this paper, we concentrate on a gate assignment problem (GAP) at the airlines terminal. Our problem is to assign an arrival plane to a suitable gate. There are two considerations needed to take. One of its is passenger walking distance from arrival gate to departure gate while another consideration is the transport baggage distance from one gate to another. Our objective is to minimize the total distance between the gates that related to assign the arrival plane to the suitable gates. An integer linear programming (ILP) model is proposed to solve this gate assignment problem. We also conduct a computational experiment using CPLEX 12.1 solver in AIMMS 3.10 software to analyze the performance of the model. Results of the computational experiments are presented. The efficiency of flights assignment is depends on the ratio of the weight for both total passenger traveling distances and total baggage transport distances.
An integer programming framework for inferring disease complexes from network data
Mazza, Arnon; Klockmeier, Konrad; Wanker, Erich; Sharan, Roded
2016-01-01
Motivation: Unraveling the molecular mechanisms that underlie disease calls for methods that go beyond the identification of single causal genes to inferring larger protein assemblies that take part in the disease process. Results: Here, we develop an exact, integer-programming-based method for associating protein complexes with disease. Our approach scores proteins based on their proximity in a protein–protein interaction network to a prior set that is known to be relevant for the studied disease. These scores are combined with interaction information to infer densely interacting protein complexes that are potentially disease-associated. We show that our method outperforms previous ones and leads to predictions that are well supported by current experimental data and literature knowledge. Availability and Implementation: The datasets we used, the executables and the results are available at www.cs.tau.ac.il/roded/disease_complexes.zip Contact: roded@post.tau.ac.il PMID:27307626
Synchronic interval Gaussian mixed-integer programming for air quality management.
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
Synchronic interval Gaussian mixed-integer programming for air quality management.
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
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.
He, Li; Huang, Guo-He; Zeng, Guang-Ming; Lu, Hong-Wei
2009-01-01
The previous inexact mixed-integer linear programming (IMILP) method can only tackle problems with coefficients of the objective function and constraints being crisp intervals, while the existing inexact mixed-integer semi-infinite programming (IMISIP) method can only deal with single-objective programming problems as it merely allows the number of constraints to be infinite. This study proposes, an inexact mixed-integer bi-infinite programming (IMIBIP) method by incorporating the concept of functional intervals into the programming framework. Different from the existing methods, the IMIBIP can tackle the inexact programming problems that contain both infinite objectives and constraints. The developed method is applied to capacity planning of waste management systems under a variety of uncertainties. Four scenarios are considered for comparing the solutions of IMIBIP with those of IMILP. The results indicate that reasonable solutions can be generated by the IMIBIP method. Compared with IMILP, the system cost from IMIBIP would be relatively high since the fluctuating market factors are considered; however, the IMILP solutions are associated with a raised system reliability level and a reduced constraint violation risk level. PMID:18406594
Multiple nuclei tracking using integer programming for quantitative cancer cell cycle analysis.
Li, Fuhai; Zhou, Xiaobo; Ma, Jinwen; Wong, Stephen T C
2010-01-01
Automated cell segmentation and tracking are critical for quantitative analysis of cell cycle behavior using time-lapse fluorescence microscopy. However, the complex, dynamic cell cycle behavior poses new challenges to the existing image segmentation and tracking methods. This paper presents a fully automated tracking method for quantitative cell cycle analysis. In the proposed tracking method, we introduce a neighboring graph to characterize the spatial distribution of neighboring nuclei, and a novel dissimilarity measure is designed based on the spatial distribution, nuclei morphological appearance, migration, and intensity information. Then, we employ the integer programming and division matching strategy, together with the novel dissimilarity measure, to track cell nuclei. We applied this new tracking method for the tracking of HeLa cancer cells over several cell cycles, and the validation results showed that the high accuracy for segmentation and tracking at 99.5% and 90.0%, respectively. The tracking method has been implemented in the cell-cycle analysis software package, DCELLIQ, which is freely available. PMID:19643704
Li, Zhenping; Zhang, Xiang-Sun; Wang, Rui-Sheng; Liu, Hongwei; Zhang, Shihua
2013-01-01
Identification of communities in complex networks is an important topic and issue in many fields such as sociology, biology, and computer science. Communities are often defined as groups of related nodes or links that correspond to functional subunits in the corresponding complex systems. While most conventional approaches have focused on discovering communities of nodes, some recent studies start partitioning links to find overlapping communities straightforwardly. In this paper, we propose a new quantity function for link community identification in complex networks. Based on this quantity function we formulate the link community partition problem into an integer programming model which allows us to partition a complex network into overlapping communities. We further propose a genetic algorithm for link community detection which can partition a network into overlapping communities without knowing the number of communities. We test our model and algorithm on both artificial networks and real-world networks. The results demonstrate that the model and algorithm are efficient in detecting overlapping community structure in complex networks.
An integer programming approach to the phase problem for centrosymmetric structures.
Vaia, Anastasia; Sahinidis, Nikolaos V
2003-09-01
The problem addressed in this paper is the determination of three-dimensional structures of centrosymmetric crystals from X-ray diffraction measurements. The 'minimal principle' that a certain quantity is minimized only by the crystal structure is employed to solve the phase problem. The mathematical formulation of the minimal principle is a nonconvex nonlinear optimization problem. To date, local optimization techniques and advanced computer architectures have been used to solve this problem, which may have a very large number of local optima. In this paper, the minimal principle model is reformulated for the case of centrosymmetric structures into an integer programming problem in terms of the missing phases. This formulation is solvable by well established combinatorial optimization techniques that are guaranteed to provide the global optimum in a finite number of steps without explicit enumeration of all possible combinations of phases. Computational experience with the proposed method on a number of structures of moderate complexity is provided and demonstrates that the approach yields a fast and reliable method that resolves the crystallographic phase problem for the case of centrosymmetric structures. PMID:12944609
Automatic design of synthetic gene circuits through mixed integer non-linear programming.
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
Poos, Alexandra M; Maicher, André; Dieckmann, Anna K; Oswald, Marcus; Eils, Roland; Kupiec, Martin; Luke, Brian; König, Rainer
2016-06-01
Understanding telomere length maintenance mechanisms is central in cancer biology as their dysregulation is one of the hallmarks for immortalization of cancer cells. Important for this well-balanced control is the transcriptional regulation of the telomerase genes. We integrated Mixed Integer Linear Programming models into a comparative machine learning based approach to identify regulatory interactions that best explain the discrepancy of telomerase transcript levels in yeast mutants with deleted regulators showing aberrant telomere length, when compared to mutants with normal telomere length. We uncover novel regulators of telomerase expression, several of which affect histone levels or modifications. In particular, our results point to the transcription factors Sum1, Hst1 and Srb2 as being important for the regulation of EST1 transcription, and we validated the effect of Sum1 experimentally. We compiled our machine learning method leading to a user friendly package for R which can straightforwardly be applied to similar problems integrating gene regulator binding information and expression profiles of samples of e.g. different phenotypes, diseases or treatments. PMID:26908654
Automatic design of synthetic gene circuits through mixed integer non-linear programming.
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.
Uncluttered Single-Image Visualization of Vascular Structures Using GPU and Integer Programming.
Won, Joong-Ho; Jeon, Yongkweon; Rosenberg, Jarrett K; Yoon, Sungroh; Rubin, Geoffrey D; Napel, Sandy
2013-01-01
Direct projection of 3D branching structures, such as networks of cables, blood vessels, or neurons onto a 2D image creates the illusion of intersecting structural parts and creates challenges for understanding and communication. We present a method for visualizing such structures, and demonstrate its utility in visualizing the abdominal aorta and its branches, whose tomographic images might be obtained by computed tomography or magnetic resonance angiography, in a single 2D stylistic image, without overlaps among branches. The visualization method, termed uncluttered single-image visualization (USIV), involves optimization of geometry. This paper proposes a novel optimization technique that utilizes an interesting connection of the optimization problem regarding USIV to the protein structure prediction problem. Adopting the integer linear programming-based formulation for the protein structure prediction problem, we tested the proposed technique using 30 visualizations produced from five patient scans with representative anatomical variants in the abdominal aortic vessel tree. The novel technique can exploit commodity-level parallelism, enabling use of general-purpose graphics processing unit (GPGPU) technology that yields a significant speedup. Comparison of the results with the other optimization technique previously reported elsewhere suggests that, in most aspects, the quality of the visualization is comparable to that of the previous one, with a significant gain in the computation time of the algorithm.
Integer Linear Programming for Constrained Multi-Aspect Committee Review Assignment.
Karimzadehgan, Maryam; Zhai, Chengxiang
2012-07-01
Automatic review assignment can significantly improve the productivity of many people such as conference organizers, journal editors and grant administrators. A general setup of the review assignment problem involves assigning a set of reviewers on a committee to a set of documents to be reviewed under the constraint of review quota so that the reviewers assigned to a document can collectively cover multiple topic aspects of the document. No previous work has addressed such a setup of committee review assignments while also considering matching multiple aspects of topics and expertise. In this paper, we tackle the problem of committee review assignment with multi-aspect expertise matching by casting it as an integer linear programming problem. The proposed algorithm can naturally accommodate any probabilistic or deterministic method for modeling multiple aspects to automate committee review assignments. Evaluation using a multi-aspect review assignment test set constructed using ACM SIGIR publications shows that the proposed algorithm is effective and efficient for committee review assignments based on multi-aspect expertise matching.
iPoint: an integer programming based algorithm for inferring protein subnetworks.
Atias, Nir; Sharan, Roded
2013-07-01
Large scale screening experiments have become the workhorse of molecular biology, producing data at an ever increasing scale. The interpretation of such data, particularly in the context of a protein interaction network, has the potential to shed light on the molecular pathways underlying the phenotype or the process in question. A host of approaches have been developed in recent years to tackle this reconstruction challenge. These approaches aim to infer a compact subnetwork that connects the genes revealed by the screen while optimizing local (individual path lengths) or global (likelihood) aspects of the subnetwork. Yosef et al. [Mol. Syst. Biol., 2009, 5, 248] were the first to provide a joint optimization of both criteria, albeit approximate in nature. Here we devise an integer linear programming formulation for the joint optimization problem, allowing us to solve it to optimality in minutes on current networks. We apply our algorithm, iPoint, to various data sets in yeast and human and evaluate its performance against state-of-the-art algorithms. We show that iPoint attains very compact and accurate solutions that outperform previous network inference algorithms with respect to their local and global attributes, their consistency across multiple experiments targeting the same pathway, and their agreement with current biological knowledge.
An integer programming formulation of the parsimonious loss of heterozygosity problem.
Catanzaro, Daniele; Labbé, Martine; Halldórsson, Bjarni V
2013-01-01
A loss of heterozygosity (LOH) event occurs when, by the laws of Mendelian inheritance, an individual should be heterozygote at a given site but, due to a deletion polymorphism, is not. Deletions play an important role in human disease and their detection could provide fundamental insights for the development of new diagnostics and treatments. In this paper, we investigate the parsimonious loss of heterozygosity problem (PLOHP), i.e., the problem of partitioning suspected polymorphisms from a set of individuals into a minimum number of deletion areas. Specifically, we generalize Halldórsson et al.'s work by providing a more general formulation of the PLOHP and by showing how one can incorporate different recombination rates and prior knowledge about the locations of deletions. Moreover, we show that the PLOHP can be formulated as a specific version of the clique partition problem in a particular class of graphs called undirected catch-point interval graphs and we prove its general $({\\cal NP})$-hardness. Finally, we provide a state-of-the-art integer programming (IP) formulation and strengthening valid inequalities to exactly solve real instances of the PLOHP containing up to 9,000 individuals and 3,000 SNPs. Our results give perspectives on the mathematics of the PLOHP and suggest new directions on the development of future efficient exact solution approaches.
Poos, Alexandra M.; Maicher, André; Dieckmann, Anna K.; Oswald, Marcus; Eils, Roland; Kupiec, Martin; Luke, Brian; König, Rainer
2016-01-01
Understanding telomere length maintenance mechanisms is central in cancer biology as their dysregulation is one of the hallmarks for immortalization of cancer cells. Important for this well-balanced control is the transcriptional regulation of the telomerase genes. We integrated Mixed Integer Linear Programming models into a comparative machine learning based approach to identify regulatory interactions that best explain the discrepancy of telomerase transcript levels in yeast mutants with deleted regulators showing aberrant telomere length, when compared to mutants with normal telomere length. We uncover novel regulators of telomerase expression, several of which affect histone levels or modifications. In particular, our results point to the transcription factors Sum1, Hst1 and Srb2 as being important for the regulation of EST1 transcription, and we validated the effect of Sum1 experimentally. We compiled our machine learning method leading to a user friendly package for R which can straightforwardly be applied to similar problems integrating gene regulator binding information and expression profiles of samples of e.g. different phenotypes, diseases or treatments. PMID:26908654
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.
Gorissen, Bram L; den Hertog, Dick; Hoffmann, Aswin L
2013-02-21
Current inverse treatment planning methods that optimize both catheter positions and dwell times in prostate HDR brachytherapy use surrogate linear or quadratic objective functions that have no direct interpretation in terms of dose-volume histogram (DVH) criteria, do not result in an optimum or have long solution times. We decrease the solution time of the existing linear and quadratic dose-based programming models (LP and QP, respectively) to allow optimizing over potential catheter positions using mixed integer programming. An additional average speed-up of 75% can be obtained by stopping the solver at an early stage, without deterioration of the plan quality. For a fixed catheter configuration, the dwell time optimization model LP solves to optimality in less than 15 s, which confirms earlier results. We propose an iterative procedure for QP that allows us to prescribe the target dose as an interval, while retaining independence between the solution time and the number of dose calculation points. This iterative procedure is comparable in speed to the LP model and produces better plans than the non-iterative QP. We formulate a new dose-volume-based model that maximizes V(100%) while satisfying pre-set DVH criteria. This model optimizes both catheter positions and dwell times within a few minutes depending on prostate volume and number of catheters, optimizes dwell times within 35 s and gives better DVH statistics than dose-based models. The solutions suggest that the correlation between the objective value and the clinical plan quality is weak in the existing dose-based models. PMID:23363622
Munguia, Lluis-Miquel; Oxberry, Geoffrey; Rajan, Deepak
2016-05-01
Stochastic mixed-integer programs (SMIPs) deal with optimization under uncertainty at many levels of the decision-making process. When solved as extensive formulation mixed- integer programs, problem instances can exceed available memory on a single workstation. In order to overcome this limitation, we present PIPS-SBB: a distributed-memory parallel stochastic MIP solver that takes advantage of parallelism at multiple levels of the optimization process. We also show promising results on the SIPLIB benchmark by combining methods known for accelerating Branch and Bound (B&B) methods with new ideas that leverage the structure of SMIPs. Finally, we expect the performance of PIPS-SBB to improve furthermore » as more functionality is added in the future.« less
Doolittle, R.
1994-11-15
The title integer anatomy is intended to convey the idea of a systematic method for displaying the prime decomposition of the integers. Just as the biological study of anatomy does not teach us all things about behavior of species neither would we expect to learn everything about the number theory from a study of its anatomy. But, some number-theoretic theorems are illustrated by inspection of integer anatomy, which tend to validate the underlying structure and the form as developed and displayed in this treatise. The first statement to be made in this development is: the way structure of the natural numbers is displayed depends upon the allowed operations.
Aspect-Object Alignment with Integer Linear Programming in Opinion Mining
Zhao, Yanyan; Qin, Bing; Liu, Ting; Yang, Wei
2015-01-01
Target extraction is an important task in opinion mining. In this task, a complete target consists of an aspect and its corresponding object. However, previous work has always simply regarded the aspect as the target itself and has ignored the important "object" element. Thus, these studies have addressed incomplete targets, which are of limited use for practical applications. This paper proposes a novel and important sentiment analysis task, termed aspect-object alignment, to solve the "object neglect" problem. The objective of this task is to obtain the correct corresponding object for each aspect. We design a two-step framework for this task. We first provide an aspect-object alignment classifier that incorporates three sets of features, namely, the basic, relational, and special target features. However, the objects that are assigned to aspects in a sentence often contradict each other and possess many complicated features that are difficult to incorporate into a classifier. To resolve these conflicts, we impose two types of constraints in the second step: intra-sentence constraints and inter-sentence constraints. These constraints are encoded as linear formulations, and Integer Linear Programming (ILP) is used as an inference procedure to obtain a final global decision that is consistent with the constraints. Experiments on a corpus in the camera domain demonstrate that the three feature sets used in the aspect-object alignment classifier are effective in improving its performance. Moreover, the classifier with ILP inference performs better than the classifier without it, thereby illustrating that the two types of constraints that we impose are beneficial. PMID:26000635
Aspect-object alignment with Integer Linear Programming in opinion mining.
Zhao, Yanyan; Qin, Bing; Liu, Ting; Yang, Wei
2015-01-01
Target extraction is an important task in opinion mining. In this task, a complete target consists of an aspect and its corresponding object. However, previous work has always simply regarded the aspect as the target itself and has ignored the important "object" element. Thus, these studies have addressed incomplete targets, which are of limited use for practical applications. This paper proposes a novel and important sentiment analysis task, termed aspect-object alignment, to solve the "object neglect" problem. The objective of this task is to obtain the correct corresponding object for each aspect. We design a two-step framework for this task. We first provide an aspect-object alignment classifier that incorporates three sets of features, namely, the basic, relational, and special target features. However, the objects that are assigned to aspects in a sentence often contradict each other and possess many complicated features that are difficult to incorporate into a classifier. To resolve these conflicts, we impose two types of constraints in the second step: intra-sentence constraints and inter-sentence constraints. These constraints are encoded as linear formulations, and Integer Linear Programming (ILP) is used as an inference procedure to obtain a final global decision that is consistent with the constraints. Experiments on a corpus in the camera domain demonstrate that the three feature sets used in the aspect-object alignment classifier are effective in improving its performance. Moreover, the classifier with ILP inference performs better than the classifier without it, thereby illustrating that the two types of constraints that we impose are beneficial. PMID:26000635
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.
Mitsos, Alexander; Melas, Ioannis N; Siminelakis, Paraskeuas; Chairakaki, Aikaterini D; Saez-Rodriguez, Julio; Alexopoulos, Leonidas G
2009-12-01
Understanding the mechanisms of cell function and drug action is a major endeavor in the pharmaceutical industry. Drug effects are governed by the intrinsic properties of the drug (i.e., selectivity and potency) and the specific signaling transduction network of the host (i.e., normal vs. diseased cells). Here, we describe an unbiased, phosphoproteomic-based approach to identify drug effects by monitoring drug-induced topology alterations. With our proposed method, drug effects are investigated under diverse stimulations of the signaling network. Starting with a generic pathway made of logical gates, we build a cell-type specific map by constraining it to fit 13 key phopshoprotein signals under 55 experimental conditions. Fitting is performed via an Integer Linear Program (ILP) formulation and solution by standard ILP solvers; a procedure that drastically outperforms previous fitting schemes. Then, knowing the cell's topology, we monitor the same key phosphoprotein signals under the presence of drug and we re-optimize the specific map to reveal drug-induced topology alterations. To prove our case, we make a topology for the hepatocytic cell-line HepG2 and we evaluate the effects of 4 drugs: 3 selective inhibitors for the Epidermal Growth Factor Receptor (EGFR) and a non-selective drug. We confirm effects easily predictable from the drugs' main target (i.e., EGFR inhibitors blocks the EGFR pathway) but we also uncover unanticipated effects due to either drug promiscuity or the cell's specific topology. An interesting finding is that the selective EGFR inhibitor Gefitinib inhibits signaling downstream the Interleukin-1alpha (IL1alpha) pathway; an effect that cannot be extracted from binding affinity-based approaches. Our method represents an unbiased approach to identify drug effects on small to medium size pathways which is scalable to larger topologies with any type of signaling interventions (small molecules, RNAi, etc). The method can reveal drug effects on
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.
Aspect-object alignment with Integer Linear Programming in opinion mining.
Zhao, Yanyan; Qin, Bing; Liu, Ting; Yang, Wei
2015-01-01
Target extraction is an important task in opinion mining. In this task, a complete target consists of an aspect and its corresponding object. However, previous work has always simply regarded the aspect as the target itself and has ignored the important "object" element. Thus, these studies have addressed incomplete targets, which are of limited use for practical applications. This paper proposes a novel and important sentiment analysis task, termed aspect-object alignment, to solve the "object neglect" problem. The objective of this task is to obtain the correct corresponding object for each aspect. We design a two-step framework for this task. We first provide an aspect-object alignment classifier that incorporates three sets of features, namely, the basic, relational, and special target features. However, the objects that are assigned to aspects in a sentence often contradict each other and possess many complicated features that are difficult to incorporate into a classifier. To resolve these conflicts, we impose two types of constraints in the second step: intra-sentence constraints and inter-sentence constraints. These constraints are encoded as linear formulations, and Integer Linear Programming (ILP) is used as an inference procedure to obtain a final global decision that is consistent with the constraints. Experiments on a corpus in the camera domain demonstrate that the three feature sets used in the aspect-object alignment classifier are effective in improving its performance. Moreover, the classifier with ILP inference performs better than the classifier without it, thereby illustrating that the two types of constraints that we impose are beneficial.
Yang, Ruijie; Dai, Jianrong; Yang, Yong; Hu, Yimin
2006-08-01
The purpose of this study is to extend an algorithm proposed for beam orientation optimization in classical conformal radiotherapy to intensity-modulated radiation therapy (IMRT) and to evaluate the algorithm's performance in IMRT scenarios. In addition, the effect of the candidate pool of beam orientations, in terms of beam orientation resolution and starting orientation, on the optimized beam configuration, plan quality and optimization time is also explored. The algorithm is based on the technique of mixed integer linear programming in which binary and positive float variables are employed to represent candidates for beam orientation and beamlet weights in beam intensity maps. Both beam orientations and beam intensity maps are simultaneously optimized in the algorithm with a deterministic method. Several different clinical cases were used to test the algorithm and the results show that both target coverage and critical structures sparing were significantly improved for the plans with optimized beam orientations compared to those with equi-spaced beam orientations. The calculation time was less than an hour for the cases with 36 binary variables on a PC with a Pentium IV 2.66 GHz processor. It is also found that decreasing beam orientation resolution to 10 degrees greatly reduced the size of the candidate pool of beam orientations without significant influence on the optimized beam configuration and plan quality, while selecting different starting orientations had large influence. Our study demonstrates that the algorithm can be applied to IMRT scenarios, and better beam orientation configurations can be obtained using this algorithm. Furthermore, the optimization efficiency can be greatly increased through proper selection of beam orientation resolution and starting beam orientation while guaranteeing the optimized beam configurations and plan quality.
Mixed integer programming model for optimizing the layout of an ICU vehicle
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
NASA Astrophysics Data System (ADS)
Li, Hong; Zhang, Li; Jiao, Yong-Chang
2016-07-01
This paper presents an interactive approach based on a discrete differential evolution algorithm to solve a class of integer bilevel programming problems, in which integer decision variables are controlled by an upper-level decision maker and real-value or continuous decision variables are controlled by a lower-level decision maker. Using the Karush--Kuhn-Tucker optimality conditions in the lower-level programming, the original discrete bilevel formulation can be converted into a discrete single-level nonlinear programming problem with the complementarity constraints, and then the smoothing technique is applied to deal with the complementarity constraints. Finally, a discrete single-level nonlinear programming problem is obtained, and solved by an interactive approach. In each iteration, for each given upper-level discrete variable, a system of nonlinear equations including the lower-level variables and Lagrange multipliers is solved first, and then a discrete nonlinear programming problem only with inequality constraints is handled by using a discrete differential evolution algorithm. Simulation results show the effectiveness of the proposed approach.
Li, Y P; Huang, G H
2006-11-01
In this study, an interval-parameter two-stage mixed integer linear programming (ITMILP) model is developed for supporting long-term planning of waste management activities in the City of Regina. In the ITMILP, both two-stage stochastic programming and interval linear programming are introduced into a general mixed integer linear programming framework. Uncertainties expressed as not only probability density functions but also discrete intervals can be reflected. The model can help tackle the dynamic, interactive and uncertain characteristics of the solid waste management system in the City, and can address issues concerning plans for cost-effective waste diversion and landfill prolongation. Three scenarios are considered based on different waste management policies. The results indicate that reasonable solutions have been generated. They are valuable for supporting the adjustment or justification of the existing waste flow allocation patterns, the long-term capacity planning of the City's waste management system, and the formulation of local policies and regulations regarding waste generation and management. PMID:16678336
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.
Song, Jiangning; Akutsu, Tatsuya
2014-01-01
In this paper, we consider the Minimum Reaction Insertion (MRI) problem for finding the minimum number of additional reactions from a reference metabolic network to a host metabolic network so that a target compound becomes producible in the revised host metabolic network in a Boolean model. Although a similar problem for larger networks is solvable in a flux balance analysis (FBA)-based model, the solution of the FBA-based model tends to include more reactions than that of the Boolean model. However, solving MRI using the Boolean model is computationally more expensive than using the FBA-based model since the Boolean model needs more integer variables. Therefore, in this study, to solve MRI for larger networks in the Boolean model, we have developed an efficient Integer Programming formalization method in which the number of integer variables is reduced by the notion of feedback vertex set and minimal valid assignment. As a result of computer experiments conducted using the data of metabolic networks of E. coli and reference networks downloaded from the Kyoto Encyclopedia of Genes and Genomes (KEGG) database, we have found that the developed method can appropriately solve MRI in the Boolean model and is applicable to large scale-networks for which an exhaustive search does not work. We have also compared the developed method with the existing connectivity-based methods and FBA-based methods, and show the difference between the solutions of our method and the existing methods. A theoretical analysis of MRI is also conducted, and the NP-completeness of MRI is proved in the Boolean model. Our developed software is available at “http://sunflower.kuicr.kyoto-u.ac.jp/~rogi/minRect/minRect.html.” PMID:24651476
Lu, Wei; Tamura, Takeyuki; Song, Jiangning; Akutsu, Tatsuya
2014-01-01
In this paper, we consider the Minimum Reaction Insertion (MRI) problem for finding the minimum number of additional reactions from a reference metabolic network to a host metabolic network so that a target compound becomes producible in the revised host metabolic network in a Boolean model. Although a similar problem for larger networks is solvable in a flux balance analysis (FBA)-based model, the solution of the FBA-based model tends to include more reactions than that of the Boolean model. However, solving MRI using the Boolean model is computationally more expensive than using the FBA-based model since the Boolean model needs more integer variables. Therefore, in this study, to solve MRI for larger networks in the Boolean model, we have developed an efficient Integer Programming formalization method in which the number of integer variables is reduced by the notion of feedback vertex set and minimal valid assignment. As a result of computer experiments conducted using the data of metabolic networks of E. coli and reference networks downloaded from the Kyoto Encyclopedia of Genes and Genomes (KEGG) database, we have found that the developed method can appropriately solve MRI in the Boolean model and is applicable to large scale-networks for which an exhaustive search does not work. We have also compared the developed method with the existing connectivity-based methods and FBA-based methods, and show the difference between the solutions of our method and the existing methods. A theoretical analysis of MRI is also conducted, and the NP-completeness of MRI is proved in the Boolean model. Our developed software is available at "http://sunflower.kuicr.kyoto-u.ac.jp/~rogi/minRect/minRect.html."
NASA Astrophysics Data System (ADS)
Yin, Sisi; Nishi, Tatsushi
2014-11-01
Quantity discount policy is decision-making for trade-off prices between suppliers and manufacturers while production is changeable due to demand fluctuations in a real market. In this paper, quantity discount models which consider selection of contract suppliers, production quantity and inventory simultaneously are addressed. The supply chain planning problem with quantity discounts under demand uncertainty is formulated as a mixed-integer nonlinear programming problem (MINLP) with integral terms. We apply an outer-approximation method to solve MINLP problems. In order to improve the efficiency of the proposed method, the problem is reformulated as a stochastic model replacing the integral terms by using a normalisation technique. We present numerical examples to demonstrate the efficiency of the proposed method.
Catanzaro, Daniele; Shackney, Stanley E; Schaffer, Alejandro A; Schwartz, Russell
2016-01-01
Ductal Carcinoma In Situ (DCIS) is a precursor lesion of Invasive Ductal Carcinoma (IDC) of the breast. Investigating its temporal progression could provide fundamental new insights for the development of better diagnostic tools to predict which cases of DCIS will progress to IDC. We investigate the problem of reconstructing a plausible progression from single-cell sampled data of an individual with synchronous DCIS and IDC. Specifically, by using a number of assumptions derived from the observation of cellular atypia occurring in IDC, we design a possible predictive model using integer linear programming (ILP). Computational experiments carried out on a preexisting data set of 13 patients with simultaneous DCIS and IDC show that the corresponding predicted progression models are classifiable into categories having specific evolutionary characteristics. The approach provides new insights into mechanisms of clonal progression in breast cancers and helps illustrate the power of the ILP approach for similar problems in reconstructing tumor evolution scenarios under complex sets of constraints.
NASA Astrophysics Data System (ADS)
Noor-E-Alam, Md.; Doucette, John
2015-08-01
Grid-based location problems (GBLPs) can be used to solve location problems in business, engineering, resource exploitation, and even in the field of medical sciences. To solve these decision problems, an integer linear programming (ILP) model is designed and developed to provide the optimal solution for GBLPs considering fixed cost criteria. Preliminary results show that the ILP model is efficient in solving small to moderate-sized problems. However, this ILP model becomes intractable in solving large-scale instances. Therefore, a decomposition heuristic is proposed to solve these large-scale GBLPs, which demonstrates significant reduction of solution runtimes. To benchmark the proposed heuristic, results are compared with the exact solution via ILP. The experimental results show that the proposed method significantly outperforms the exact method in runtime with minimal (and in most cases, no) loss of optimality.
DRIESSEN,BRIAN; SADEGH,NADER
2000-04-25
This work presents a method of finding near global optima to minimum-time trajectory generation problem for systems that would be linear if it were not for the presence of Coloumb friction. The required final state of the system is assumed to be maintainable by the system, and the input bounds are assumed to be large enough so that they can overcome the maximum static Coloumb friction force. Other than the previous work for generating minimum-time trajectories for non redundant robotic manipulators for which the path in joint space is already specified, this work represents, to the best of the authors' knowledge, the first approach for generating near global optima for minimum-time problems involving a nonlinear class of dynamic systems. The reason the optima generated are near global optima instead of exactly global optima is due to a discrete-time approximation of the system (which is usually used anyway to simulate such a system numerically). The method closely resembles previous methods for generating minimum-time trajectories for linear systems, where the core operation is the solution of a Phase I linear programming problem. For the nonlinear systems considered herein, the core operation is instead the solution of a mixed integer linear programming problem.
Lee, Dongyul; Lee, Chaewoo
2014-01-01
The advancement in wideband wireless network supports real time services such as IPTV and live video streaming. However, because of the sharing nature of the wireless medium, efficient resource allocation has been studied to achieve a high level of acceptability and proliferation of wireless multimedia. Scalable video coding (SVC) with adaptive modulation and coding (AMC) provides an excellent solution for wireless video streaming. By assigning different modulation and coding schemes (MCSs) to video layers, SVC can provide good video quality to users in good channel conditions and also basic video quality to users in bad channel conditions. For optimal resource allocation, a key issue in applying SVC in the wireless multicast service is how to assign MCSs and the time resources to each SVC layer in the heterogeneous channel condition. We formulate this problem with integer linear programming (ILP) and provide numerical results to show the performance under 802.16 m environment. The result shows that our methodology enhances the overall system throughput compared to an existing algorithm.
Lee, Chaewoo
2014-01-01
The advancement in wideband wireless network supports real time services such as IPTV and live video streaming. However, because of the sharing nature of the wireless medium, efficient resource allocation has been studied to achieve a high level of acceptability and proliferation of wireless multimedia. Scalable video coding (SVC) with adaptive modulation and coding (AMC) provides an excellent solution for wireless video streaming. By assigning different modulation and coding schemes (MCSs) to video layers, SVC can provide good video quality to users in good channel conditions and also basic video quality to users in bad channel conditions. For optimal resource allocation, a key issue in applying SVC in the wireless multicast service is how to assign MCSs and the time resources to each SVC layer in the heterogeneous channel condition. We formulate this problem with integer linear programming (ILP) and provide numerical results to show the performance under 802.16 m environment. The result shows that our methodology enhances the overall system throughput compared to an existing algorithm. PMID:25276862
Ryan, Jason C; Banerjee, Ashis Gopal; Cummings, Mary L; Roy, Nicholas
2014-06-01
Planning operations across a number of domains can be considered as resource allocation problems with timing constraints. An unexplored instance of such a problem domain is the aircraft carrier flight deck, where, in current operations, replanning is done without the aid of any computerized decision support. Rather, veteran operators employ a set of experience-based heuristics to quickly generate new operating schedules. These expert user heuristics are neither codified nor evaluated by the United States Navy; they have grown solely from the convergent experiences of supervisory staff. As unmanned aerial vehicles (UAVs) are introduced in the aircraft carrier domain, these heuristics may require alterations due to differing capabilities. The inclusion of UAVs also allows for new opportunities for on-line planning and control, providing an alternative to the current heuristic-based replanning methodology. To investigate these issues formally, we have developed a decision support system for flight deck operations that utilizes a conventional integer linear program-based planning algorithm. In this system, a human operator sets both the goals and constraints for the algorithm, which then returns a proposed schedule for operator approval. As a part of validating this system, the performance of this collaborative human-automation planner was compared with that of the expert user heuristics over a set of test scenarios. The resulting analysis shows that human heuristics often outperform the plans produced by an optimization algorithm, but are also often more conservative.
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/. PMID:26756402
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/.
Guo, P; Huang, G H
2010-03-01
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
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
NASA Astrophysics Data System (ADS)
Uilhoorn, F. E.
2016-10-01
In this article, the stochastic modelling approach proposed by Box and Jenkins is treated as a mixed-integer nonlinear programming (MINLP) problem solved with a mesh adaptive direct search and a real-coded genetic class of algorithms. The aim is to estimate the real-valued parameters and non-negative integer, correlated structure of stationary autoregressive moving average (ARMA) processes. The maximum likelihood function of the stationary ARMA process is embedded in Akaike's information criterion and the Bayesian information criterion, whereas the estimation procedure is based on Kalman filter recursions. The constraints imposed on the objective function enforce stability and invertibility. The best ARMA model is regarded as the global minimum of the non-convex MINLP problem. The robustness and computational performance of the MINLP solvers are compared with brute-force enumeration. Numerical experiments are done for existing time series and one new data set.
ERIC Educational Resources Information Center
Dirks, Michael K.
1984-01-01
The abacus method for instruction on addition, subtraction, and multiplication with integers is explained. How to represent the integers for each operation is detailed with words and illustrations. (MNS)
ERIC Educational Resources Information Center
Pong, Wai Yan
2007-01-01
We begin by answering the question, "Which natural numbers are sums of consecutive integers?" We then go on to explore the set of lengths (numbers of summands) in the decompositions of an integer as such sums.
ERIC Educational Resources Information Center
Siegel, Jonathan W.; Siegel, P. B.
2011-01-01
Integers are sometimes used in physics problems to simplify the mathematics so the arithmetic does not distract students from the physics concepts. This is particularly important in exams where students should not have to spend a lot of time using their calculators. Common uses of integers in physics problems include integer solutions to…
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.
Wang, S; Huang, G H
2013-03-15
Flood disasters have been extremely severe in recent decades, and they account for about one third of all natural catastrophes throughout the world. In this study, a two-stage mixed-integer fuzzy programming with interval-valued membership functions (TMFP-IMF) approach is developed for flood-diversion planning under uncertainty. TMFP-IMF integrates the fuzzy flexible programming, two-stage stochastic programming, and integer programming within a general framework. A concept of interval-valued fuzzy membership function is introduced to address complexities of system uncertainties. TMFP-IMF can not only deal with uncertainties expressed as fuzzy sets and probability distributions, but also incorporate pre-regulated water-diversion policies directly into its optimization process. TMFP-IMF is applied to a hypothetical case study of flood-diversion planning for demonstrating its applicability. Results indicate that reasonable solutions can be generated for binary and continuous variables. A variety of flood-diversion and capacity-expansion schemes can be obtained under four scenarios, which enable decision makers (DMs) to identify the most desired one based on their perceptions and attitudes towards the objective-function value and constraints.
Guo, P; Huang, G H
2009-01-01
In this study, an inexact fuzzy chance-constrained two-stage mixed-integer linear programming (IFCTIP) approach is proposed for supporting long-term planning of waste-management systems under multiple uncertainties in the City of Regina, Canada. The method improves upon the existing inexact two-stage programming and mixed-integer linear programming techniques by incorporating uncertainties expressed as multiple uncertainties of intervals and dual probability distributions within a general optimization framework. The developed method can provide an effective linkage between the predefined environmental policies and the associated economic implications. Four special characteristics of the proposed method make it unique compared with other optimization techniques that deal with uncertainties. Firstly, it provides a linkage to predefined policies that have to be respected when a modeling effort is undertaken; secondly, it is useful for tackling uncertainties presented as intervals, probabilities, fuzzy sets and their incorporation; thirdly, it facilitates dynamic analysis for decisions of facility-expansion planning and waste-flow allocation within a multi-facility, multi-period, multi-level, and multi-option context; fourthly, the penalties are exercised with recourse against any infeasibility, which permits in-depth analyses of various policy scenarios that are associated with different levels of economic consequences when the promised solid waste-generation rates are violated. In a companion paper, the developed method is applied to a real case for the long-term planning of waste management in the City of Regina, Canada. PMID:19800164
Guo, P; Huang, G H
2009-01-01
In this study, an inexact fuzzy chance-constrained two-stage mixed-integer linear programming (IFCTIP) approach is proposed for supporting long-term planning of waste-management systems under multiple uncertainties in the City of Regina, Canada. The method improves upon the existing inexact two-stage programming and mixed-integer linear programming techniques by incorporating uncertainties expressed as multiple uncertainties of intervals and dual probability distributions within a general optimization framework. The developed method can provide an effective linkage between the predefined environmental policies and the associated economic implications. Four special characteristics of the proposed method make it unique compared with other optimization techniques that deal with uncertainties. Firstly, it provides a linkage to predefined policies that have to be respected when a modeling effort is undertaken; secondly, it is useful for tackling uncertainties presented as intervals, probabilities, fuzzy sets and their incorporation; thirdly, it facilitates dynamic analysis for decisions of facility-expansion planning and waste-flow allocation within a multi-facility, multi-period, multi-level, and multi-option context; fourthly, the penalties are exercised with recourse against any infeasibility, which permits in-depth analyses of various policy scenarios that are associated with different levels of economic consequences when the promised solid waste-generation rates are violated. In a companion paper, the developed method is applied to a real case for the long-term planning of waste management in the City of Regina, Canada.
Albuquerque, Fabio; Beier, Paul
2015-01-01
Here we report that prioritizing sites in order of rarity-weighted richness (RWR) is a simple, reliable way to identify sites that represent all species in the fewest number of sites (minimum set problem) or to identify sites that represent the largest number of species within a given number of sites (maximum coverage problem). We compared the number of species represented in sites prioritized by RWR to numbers of species represented in sites prioritized by the Zonation software package for 11 datasets in which the size of individual planning units (sites) ranged from <1 ha to 2,500 km2. On average, RWR solutions were more efficient than Zonation solutions. Integer programming remains the only guaranteed way find an optimal solution, and heuristic algorithms remain superior for conservation prioritizations that consider compactness and multiple near-optimal solutions in addition to species representation. But because RWR can be implemented easily and quickly in R or a spreadsheet, it is an attractive alternative to integer programming or heuristic algorithms in some conservation prioritization contexts. PMID:25780930
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.
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.
El-Qulity, Said Ali; Mohamed, Ali Wagdy
2016-01-01
This paper proposes a nonlinear integer goal programming model (NIGPM) for solving the general problem of admission capacity planning in a country as a whole. The work aims to satisfy most of the required key objectives of a country related to the enrollment problem for higher education. The system general outlines are developed along with the solution methodology for application to the time horizon in a given plan. The up-to-date data for Saudi Arabia is used as a case study and a novel evolutionary algorithm based on modified differential evolution (DE) algorithm is used to solve the complexity of the NIGPM generated for different goal priorities. The experimental results presented in this paper show their effectiveness in solving the admission capacity for higher education in terms of final solution quality and robustness. PMID:26819583
Simandl, Ronald F.; Brown, John D.; Whinnery, Jr., LeRoy L.
1999-01-01
In an improved ozone decomposing air filter carbon fibers are held together with a carbonized binder in a perforated structure. The structure is made by combining rayon fibers with gelatin, forming the mixture in a mold, freeze-drying, and vacuum baking.
Simandl, R.F.; Brown, J.D.; Whinnery, L.L. Jr.
1999-11-02
In an improved ozone decomposing air filter carbon fibers are held together with a carbonized binder in a perforated structure. The structure is made by combining rayon fibers with gelatin, forming the mixture in a mold, freeze-drying, and vacuum baking.
Gusfield, Dan
2010-03-01
The Multi-State Perfect Phylogeny Problem is an extension of the Binary Perfect Phylogeny Problem, allowing characters to take on more than two states. In this article, we consider three problems that extend the utility of the multi-state perfect phylogeny model: (1) the Missing Data (MD) Problem, where some entries in the input are missing and the question is whether (bounded) values for the missing data can be imputed so that the resulting data has a multi-state perfect phylogeny; (2) the Character-Removal (CR) Problem, where we want to minimize the number of characters to remove from the data so that the resulting data has a multi-state perfect phylogeny; and (3) the Missing-Data Character-Removal (MDCR) Problem, where the input has missing data and we want to impute values for the missing data to minimize the solution to the resulting Character-Removal Problem. We discuss Integer Linear Programming (ILP) solutions to these problems for the special case of three, four, and five permitted states per character, and we report on extensive empirical testing of these solutions. Then we develop a general theory to solve the MD problem for an arbitrary number of permitted states, using chordal graph theory and results on minimal triangulation of non-chordal graphs. This establishes new necessary and sufficient conditions for the existence of a perfect phylogeny with (or without) missing data. We implement the general theory using integer linear programming, although other optimization methods are possible. We extensively explore the empirical behavior of the general solution, showing that the methods are very practical for data of size and complexity that is characteristic of many current applications in phylogenetics. Some of the empirical results for the MD problem with an arbitrary number of permitted states are very surprising, suggesting the existence of additional combinatorial structure in multi-state perfect phylogenies. Finally, we note some relationships
ERIC Educational Resources Information Center
Griffiths, Martin
2011-01-01
One of the author's undergraduate students recently asked him whether it was possible to generate a random positive integer. After some thought, the author realised that there were plenty of interesting mathematical ideas inherent in her question. So much so in fact, that the author decided to organise a workshop, open both to undergraduates and…
Meyers, C A; Schulz, A S
2009-01-07
The integer equal flow problem is an NP-hard network flow problem, in which all arcs in given sets R{sub 1}, ..., R{sub {ell}} must carry equal flow. We show this problem is effectively inapproximable, even if the cardinality of each set R{sub k} is two. When {ell} is fixed, it is solvable in polynomial time.
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.
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.
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.
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.
Computer Corner: Spreadsheets, Power Series, Generating Functions, and Integers.
ERIC Educational Resources Information Center
Snow, Donald R.
1989-01-01
Implements a table algorithm on a spreadsheet program and obtains functions for several number sequences such as the Fibonacci and Catalan numbers. Considers other applications of the table algorithm to integers represented in various number bases. (YP)
Mixed integer evolution strategies for parameter optimization.
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
Forensic entomology of decomposing humans and their decomposing pets.
Sanford, Michelle R
2015-02-01
Domestic pets are commonly found in the homes of decedents whose deaths are investigated by a medical examiner or coroner. When these pets become trapped with a decomposing decedent they may resort to feeding on the body or succumb to starvation and/or dehydration and begin to decompose as well. In this case report photographic documentation of cases involving pets and decedents were examined from 2009 through the beginning of 2014. This photo review indicated that in many cases the pets were cats and dogs that were trapped with the decedent, died and were discovered in a moderate (bloat to active decay) state of decomposition. In addition three cases involving decomposing humans and their decomposing pets are described as they were processed for time of insect colonization by forensic entomological approach. Differences in timing and species colonizing the human and animal bodies were noted as was the potential for the human or animal derived specimens to contaminate one another at the scene.
Charge fractionalization in the integer quantum Hall effect.
Inoue, Hiroyuki; Grivnin, Anna; Ofek, Nissim; Neder, Izhar; Heiblum, Moty; Umansky, Vladimir; Mahalu, Diana
2014-04-25
We report an observation, via sensitive shot noise measurements, of charge fractionalization of chiral edge electrons in the integer quantum Hall effect regime. Such fractionalization results solely from interchannel Coulomb interaction, leading electrons to decompose to excitations carrying fractional charges. The experiment was performed by guiding a partitioned current carrying edge channel in proximity to another unbiased edge channel, leading to shot noise in the unbiased edge channel without net current, which exhibited an unconventional dependence on the partitioning. The determination of the fractional excitations, as well as the relative velocities of the two original (prior to the interaction) channels, relied on a recent theory pertaining to this measurement. Our result exemplifies the correlated nature of multiple chiral edge channels in the integer quantum Hall effect regime.
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.
Integer Operations Using a Whiteboard
ERIC Educational Resources Information Center
Andrews, Delise R.
2011-01-01
Interactive whiteboards are somewhat unimpressive at first and look like the whiteboards that already hang on the walls of many classrooms. However, integrating interactive whiteboard technology in a unit on adding and subtracting integers enhances student engagement and understanding. In this article, the author describes how she used an…
Integers Made Easy: Just Walk It Off
ERIC Educational Resources Information Center
Nurnberger-Haag, Julie
2007-01-01
This article describes a multisensory method for teaching students how to multiply and divide as well as add and subtract integers. The author uses sidewalk chalk and the underlying concept of integers to physically and mentally engage students in understanding the concepts of integers, making connections, and developing computational fluency.…
Investigating data envelopment analysis model with potential improvement for integer output values
NASA Astrophysics Data System (ADS)
Hussain, Mushtaq Taleb; Ramli, Razamin; Khalid, Ruzelan
2015-12-01
The decrement of input proportions in DEA model is associated with its input reduction. This reduction is apparently good for economy since it could reduce unnecessary cost resources. However, in some situations the reduction of relevant inputs such as labour could create social problems. Such inputs should thus be maintained or increased. This paper develops an advanced radial DEA model dealing with mixed integer linear programming to improve integer output values through the combination of inputs. The model can deal with real input values and integer output values. This model is valuable for situations dealing with input combination to improve integer output values as faced by most organizations.
Solving the Water Jugs Problem by an Integer Sequence Approach
ERIC Educational Resources Information Center
Man, Yiu-Kwong
2012-01-01
In this article, we present an integer sequence approach to solve the classic water jugs problem. The solution steps can be obtained easily by additions and subtractions only, which is suitable for manual calculation or programming by computer. This approach can be introduced to secondary and undergraduate students, and also to teachers and…
Decomposing the emotional Stroop effect.
Frings, Christian; Englert, Julia; Wentura, Dirk; Bermeitinger, Christina
2010-01-01
The emotional Stroop effect refers to the phenomenon that participants are faster in responding to the ink colour of neutral than of negative word stimuli, possibly reflecting fast and automatic allocation of attention towards negative stimuli. However, this interpretation was challenged by McKenna and Sharma (2004) who found that the emotional Stroop effect reflected a generic slowdown after negative stimuli. In fact, they even found reversed effects in a design in which neutral stimuli more often followed negative stimuli and vice versa. Yet, besides reversing the emotional Stroop effect this contingency might in fact have counteracted the fast effect, which was usually interpreted as the emotional Stroop effect. To decompose the emotional Stroop effect we used a design in which the foregoing and the current valence were uncorrelated and in which the fast and slow effects could be computed independently from each other. We found evidence for both fast and slow effects and discuss the practical implications for researchers using the emotional Stroop task as a measurement and the theoretical implications for researchers interested in the underlying cognitive mechanisms that contribute to the emotional Stroop effect.
Order and Value: Transitioning to Integers
ERIC Educational Resources Information Center
Bofferding, Laura
2014-01-01
As students progress from working with whole numbers to working with integers, they must wrestle with the big ideas of number values and order. Using objects to show positive quantities is easy, but no physical negative quantities exist. Therefore, when talking about integers, the author refers to number values instead of number quantities. The…
Decomposing global crop yield variability
NASA Astrophysics Data System (ADS)
Ben-Ari, Tamara; Makowski, David
2014-11-01
Recent food crises have highlighted the need to better understand the between-year variability of agricultural production. Although increasing future production seems necessary, the globalization of commodity markets suggests that the food system would also benefit from enhanced supplies stability through a reduction in the year-to-year variability. Here, we develop an analytical expression decomposing global crop yield interannual variability into three informative components that quantify how evenly are croplands distributed in the world, the proportion of cultivated areas allocated to regions of above or below average variability and the covariation between yields in distinct world regions. This decomposition is used to identify drivers of interannual yield variations for four major crops (i.e., maize, rice, soybean and wheat) over the period 1961-2012. We show that maize production is fairly spread but marked by one prominent region with high levels of crop yield interannual variability (which encompasses the North American corn belt in the USA, and Canada). In contrast, global rice yields have a small variability because, although spatially concentrated, much of the production is located in regions of below-average variability (i.e., South, Eastern and South Eastern Asia). Because of these contrasted land use allocations, an even cultivated land distribution across regions would reduce global maize yield variance, but increase the variance of global yield rice. Intermediate results are obtained for soybean and wheat for which croplands are mainly located in regions with close-to-average variability. At the scale of large world regions, we find that covariances of regional yields have a negligible contribution to global yield variance. The proposed decomposition could be applied at any spatial and time scales, including the yearly time step. By addressing global crop production stability (or lack thereof) our results contribute to the understanding of a key
Factorization of large integers on a massively parallel computer
Davis, J.A.; Holdridge, D.B.
1988-01-01
Our interest in integer factorization at Sandia National Laboratories is motivated by cryptographic applications and in particular the security of the RSA encryption-decryption algorithm. We have implemented our version of the quadratic sieve procedure on the NCUBE computer with 1024 processors (nodes). The new code is significantly different in all important aspects from the program used to factor number of order 10/sup 70/ on a single processor CRAY computer. Capabilities of parallel processing and limitation of small local memory necessitated this entirely new implementation. This effort involved several restarts as realizations of program structures that seemed appealing bogged down due to inter-processor communications. We are presently working with integers of magnitude about 10/sup 70/ in tuning this code to the novel hardware. 6 refs., 3 figs.
Our World without Decomposers: How Scary!
ERIC Educational Resources Information Center
Spring, Patty; Harr, Natalie
2014-01-01
Bugs, slugs, bacteria, and fungi are decomposers at the heart of every ecosystem. Fifth graders at Dodge Intermediate School in Twinsburg, Ohio, ventured outdoors to learn about the necessity of these amazing organisms. With the help of a naturalist, students explored their local park and discovered the wonder of decomposers and their…
NASA Astrophysics Data System (ADS)
Xue, Wentong; Song, Jianshe; Yuan, Lihai; Shen, Tao
2005-11-01
An efficient and novel imagery compression system for Synthetic Aperture Radar (SAR) which uses integer to integer wavelet transform and Modified Set Partitioning Embedded Block Coder (M-SPECK) has been presented in this paper. The presence of speckle noise, detailed texture, high dynamic range in SAR images, and even its vast data volume show the great differences of SAR imagery. Integer to integer wavelet transform is invertible in finite precision arithmetic, it maps integers to integers, and approximates linear wavelet transforms from which they are derived. Considering in terms of computational load, compression ratio and subjective visual quality metrics, several filter banks are compared together and some factors affecting the compression performance of the integer to integer wavelet transform are discussed in details. Then the optimal filter banks which are more appropriate for the SAR images compression are given. Information of high frequency has relatively larger proportion in SAR images compared with those of nature images. Measures to modify the quantizing thresholds in traditional SPECK are taken, which could be suitable to the contents of SAR imagery for the purpose of compression. Both the integer to integer wavelet transform and modified SPECK have the desirable feature of low computational complexity. Experimental results show its superiority over the traditional approaches in the condition of tradeoffs between compression efficiency and computational complexity.
Integer cosine transform for image compression
NASA Technical Reports Server (NTRS)
Cheung, K.-M.; Pollara, F.; Shahshahani, M.
1991-01-01
This article describes a recently introduced transform algorithm called the integer cosine transform (ICT), which is used in transform-based data compression schemes. The ICT algorithm requires only integer operations on small integers and at the same time gives a rate-distortion performance comparable to that offered by the floating-point discrete cosine transform (DCT). The article addresses the issue of implementation complexity, which is of prime concern for source coding applications of interest in deep-space communications. Complexity reduction in the transform stage of the compression scheme is particularly relevant, since this stage accounts for most (typically over 80 percent) of the computational load.
Integer quantum Hall effect for bosons.
Senthil, T; Levin, Michael
2013-01-25
A simple physical realization of an integer quantum Hall state of interacting two dimensional bosons is provided. This is an example of a symmetry-protected topological (SPT) phase which is a generalization of the concept of topological insulators to systems of interacting bosons or fermions. Universal physical properties of the boson integer quantum Hall state are described and shown to correspond with those expected from general classifications of SPT phases.
IMC-PID-fractional-order-filter controllers design for integer order systems.
Maâmar, Bettayeb; Rachid, Mansouri
2014-09-01
One of the reasons of the great success of standard PID controllers is the presence of simple tuning rules, of the automatic tuning feature and of tables that simplify significantly their design. For the fractional order case, some tuning rules have been proposed in the literature. However, they are not general because they are valid only for some model cases. In this paper, a new approach is investigated. The fractional property is not especially imposed by the controller structure but by the closed loop reference model. The resulting controller is fractional but it has a very interesting structure for its implementation. Indeed, the controller can be decomposed into two transfer functions: an integer transfer function which is generally an integer PID controller and a simple fractional filter.
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
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.
Slip and Slide Method of Factoring Trinomials with Integer Coefficients over the Integers
ERIC Educational Resources Information Center
Donnell, William A.
2012-01-01
In intermediate and college algebra courses there are a number of methods for factoring quadratic trinomials with integer coefficients over the integers. Some of these methods have been given names, such as trial and error, reversing FOIL, AC method, middle term splitting method and slip and slide method. The purpose of this article is to discuss…
Topological Integer Additive Set-Graceful Graphs
NASA Astrophysics Data System (ADS)
Sudev, N. K.; P., K.; Germina, K. A.
2015-08-01
Let $\\mathbb{N}_0$ denote the set of all non-negative integers and $X$ be any subset of $X$. Also denote the power set of $X$ by $\\mathcal{P}(X)$. An integer additive set-labeling (IASL) of a graph $G$ is an injective function $f:V(G)\\to \\mathcal{P}(X)$ such that the induced function $f^+:E(G) \\to \\mathcal{P}(X)$ is defined by $f^+ (uv) = f(u)+ f(v)$, where $f(u)+f(v)$ is the sumset of $f(u)$ and $f(v)$. An IASL $f$ is said to be a topological IASL (Top-IASL) if $f(V(G))\\cup \\{\\emptyset\\}$ is a topology of the ground set $X$. An IASL is said to be an integer additive set-graceful labeling (IASGL) if for the induced edge-function $f^+$, $f^+(E(G))= \\mathcal{P}(X)-\\{\\emptyset, \\{0\\}\\}$. In this paper, we study certain types of IASL of a given graph $G$, which is a topological integer additive set-labeling as well as an integer additive set-graceful labeling of $G$.
Reducing Truncation Error In Integer Processing
NASA Technical Reports Server (NTRS)
Thomas, J. Brooks; Berner, Jeffrey B.; Graham, J. Scott
1995-01-01
Improved method of rounding off (truncation of least-significant bits) in integer processing of data devised. Provides for reduction, to extremely low value, of numerical bias otherwise generated by accumulation of truncation errors from many arithmetic operations. Devised for use in integer signal processing, in which rescaling and truncation usually performed to reduce number of bits, which typically builds up in sequence of operations. Essence of method to alternate direction of roundoff (plus, then minus) on alternate occurrences of truncated values contributing to bias.
PSLQ: An Algorithm to Discover Integer Relations
Bailey, David H.; Borwein, J. M.
2009-04-03
Let x = (x{sub 1}, x{sub 2} {hor_ellipsis}, x{sub n}) be a vector of real or complex numbers. x is said to possess an integer relation if there exist integers a{sub i}, not all zero, such that a{sub 1}x{sub 1} + a{sub 2}x{sub 2} + {hor_ellipsis} + a{sub n}x{sub n} = 0. By an integer relation algorithm, we mean a practical computational scheme that can recover the vector of integers ai, if it exists, or can produce bounds within which no integer relation exists. As we will see in the examples below, an integer relation algorithm can be used to recognize a computed constant in terms of a formula involving known constants, or to discover an underlying relation between quantities that can be computed to high precision. At the present time, the most effective algorithm for integer relation detection is the 'PSLQ' algorithm of mathematician-sculptor Helaman Ferguson [10, 4]. Some efficient 'multi-level' implementations of PSLQ, as well as a variant of PSLQ that is well-suited for highly parallel computer systems, are given in [4]. PSLQ constructs a sequence of integer-valued matrices B{sub n} that reduces the vector y = xB{sub n}, until either the relation is found (as one of the columns of B{sub n}), or else precision is exhausted. At the same time, PSLQ generates a steadily growing bound on the size of any possible relation. When a relation is found, the size of smallest entry of the vector y abruptly drops to roughly 'epsilon' (i.e. 10{sup -p}, where p is the number of digits of precision). The size of this drop can be viewed as a 'confidence level' that the relation is real and not merely a numerical artifact - a drop of 20 or more orders of magnitude almost always indicates a real relation. Very high precision arithmetic must be used in PSLQ. If one wishes to recover a relation of length n, with coefficients of maximum size d digits, then the input vector x must be specified to at least nd digits, and one must employ nd-digit floating-point arithmetic. Maple and
ERIC Educational Resources Information Center
Richardson, William H., Jr.
2006-01-01
Computational precision is sometimes given short shrift in a first programming course. Treating this topic requires discussing integer and floating-point number representations and inaccuracies that may result from their use. An example of a moderately simple programming problem from elementary statistics was examined. It forced students to…
Sums of Integer Squares: A New Look.
ERIC Educational Resources Information Center
Sastry, K. R. S.; Pranesachar, C. R.; Venkatachala, B. J.
1998-01-01
Focuses on the study of the sum of two integer squares, neither of which is zero square. Develops some new interesting and nonstandard ideas that can be put to use in number theory class, mathematics club meetings, or popular lectures. (ASK)
How to Differentiate an Integer Modulo n
ERIC Educational Resources Information Center
Emmons, Caleb; Krebs, Mike; Shaheen, Anthony
2009-01-01
A number derivative is a numerical mapping that satisfies the product rule. In this paper, we determine all number derivatives on the set of integers modulo n. We also give a list of undergraduate research projects to pursue using these maps as a starting point.
Dollars & Sense: Students' Integer Perspectives
ERIC Educational Resources Information Center
Whitacre, Ian; Bishop, Jessica Pierson; Philipp, Randolph A.; Lamb, Lisa L.; Schappelle, Bonnie P.
2014-01-01
A story problem about borrowing money, presented in this article, may be represented with positive or negative numbers and thought about in different ways. The authors describe ideas related to integers (both positive and negative) and how students used them in relation to a story problem, and how they related these ideas to equations.
A portable integer FFT in FORTRAN.
Monro, D M
1977-12-01
A radix 2 integer fast Fourier transform is organised for compatibility among small computer systems by simulating binary fraction multiplications and bit reversal as functions in basic FORTRAN. After installation the efficiency can be improved by machine code replacement of some parts.
Scalable Domain Decomposed Monte Carlo Particle Transport
O'Brien, Matthew Joseph
2013-12-05
In this dissertation, we present the parallel algorithms necessary to run domain decomposed Monte Carlo particle transport on large numbers of processors (millions of processors). Previous algorithms were not scalable, and the parallel overhead became more computationally costly than the numerical simulation.
Decomposing Achievement Gaps among OECD Countries
ERIC Educational Resources Information Center
Zhang, Liang; Lee, Kristen A.
2011-01-01
In this study, we use decomposition methods on PISA 2006 data to compare student academic performance across OECD countries. We first establish an empirical model to explain the variation in academic performance across individuals, and then use the Oaxaca-Blinder decomposition method to decompose the achievement gap between each of the OECD…
N2O Decomposed by Discharge Plasma with Catalysts
NASA Astrophysics Data System (ADS)
Hu, Hui; Huang, Hao; Xu, Jie; Yang, Qi; Tao, Gongkai
2015-12-01
A great deal of attention has been focused on discharge plasma as it can rapidly decompose N2O without additives, which is not only a kind of greenhouse gas but also a kind of damages to the ozone layer. The thermal equilibrium plasma is chosen to combine with catalysts to decompose N2O, and its characteristics are analyzed in the present paper. The results indicate that NO and NO2 were formed besides N2 and O2 during N2O decomposition when N2O was treated merely by discharge plasma. Concentration of NO declined greatly when the discharge plasma was combined with catalysts. Results of Raman spectra analysis on CeO2, Ce0.75Zr0.25O2 and Ce0.5Zr0.5O2 imply that the products selectivity has been obviously improved in discharge plasma decomposing N2O because of the existence of massive oxygen vacancies over the composite oxide catalysts. supported by National Natural Science Foundation of China (No. 50677026) and the Applied Basic Research Program of Wuhan, China (No. 2015060101010068)
Slip and slide method of factoring trinomials with integer coefficients over the integers
NASA Astrophysics Data System (ADS)
Donnell, William A.
2012-06-01
In intermediate and college algebra courses there are a number of methods for factoring quadratic trinomials with integer coefficients over the integers. Some of these methods have been given names, such as trial and error, reversing FOIL, AC method, middle term splitting method and slip and slide method. The purpose of this article is to discuss the Slip and Slide Method and present a theoretical justification of why it works.
Elementary theory of factoring trinomials with integer coefficients over the integers
NASA Astrophysics Data System (ADS)
Donnell, William A.
2010-12-01
An important component of intermediate and college algebra courses involves teaching students methods to factor a trinomial with integer coefficients over the integers. The aim of this article is to present a theoretical justification of that which is often taught, but really never explained as to why it works. The theory is presented, and a suggestion for an inquiry-based learning project is given.
Rational Tree Morphisms and Transducer Integer Sequences: Definition and Examples
NASA Astrophysics Data System (ADS)
ŠUnić, Zoran
2007-04-01
The notion of transducer integer sequences is considered through a series of examples (the chosen examples are related to the Tower of Hanoi problem on 3 pegs). By definition, transducer integer sequences are integer sequences produced, under a suitable interpretation, by finite transducers encoding rational tree morphisms (length and prefix preserving transformations of words that have only finitely many distinct sections).
Unlimited Capacity Parallel Quantity Comparison of Multiple Integers
ERIC Educational Resources Information Center
Blanc-Goldhammer, Daryn R.; Cohen, Dale J.
2014-01-01
Research has shown that integer comparison is quick and efficient. This efficiency may be a function of the structure of the integer comparison system. The present study tests whether integers are compared with an unlimited capacity system or a limited capacity system. We tested these models using a visual search task with time delimitation. The…
NASA Astrophysics Data System (ADS)
Chung, Won Sang
2014-07-01
In this paper a new q-deformed oscillator algebra with an integer number eigenvalue and a half odd integer number eigenvalue is proposed. For this algebra, the associated energy spectrum and thermodynamic behavior is discussed.
NASA Astrophysics Data System (ADS)
Jafarizadeh, M. A.; Mirzaee, M.; Rezaee, M.
2005-04-01
We provide an analytical expression for optimal Lewenstein-Sanpera decomposition of Bell decomposable states by using semi-definite programming. Also using the Karush-Kuhn-Tucker optimization method, the minimum relative entropy of entanglement of Bell decomposable states has been evaluated and it is shown that the same separable Bell decomposable state lying at the boundary of convex set of separable Bell decomposable states, optimizes both Lewenstein-Sanpera decomposition and relative entropy of entanglement.
Catalytic cartridge SO.sub.3 decomposer
Galloway, Terry R.
1982-01-01
A catalytic cartridge internally heated is utilized as a SO.sub.3 decomposer for thermochemical hydrogen production. The cartridge has two embodiments, a cross-flow cartridge and an axial flow cartridge. In the cross-flow cartridge, SO.sub.3 gas is flowed through a chamber and incident normally to a catalyst coated tube extending through the chamber, the catalyst coated tube being internally heated. In the axial-flow cartridge, SO.sub.3 gas is flowed through the annular space between concentric inner and outer cylindrical walls, the inner cylindrical wall being coated by a catalyst and being internally heated. The modular cartridge decomposer provides high thermal efficiency, high conversion efficiency, and increased safety.
Catalytic cartridge SO.sub.3 decomposer
Galloway, Terry R.
1982-01-01
A catalytic cartridge surrounding a heat pipe driven by a heat source is utilized as a SO.sub.3 decomposer for thermochemical hydrogen production. The cartridge has two embodiments, a cross-flow cartridge and an axial flow cartridge. In the cross-flow cartridge, SO.sub.3 gas is flowed through a chamber and incident normally to a catalyst coated tube extending through the chamber, the catalyst coated tube surrounding the heat pipe. In the axial-flow cartridge, SO.sub.3 gas is flowed through the annular space between concentric inner and outer cylindrical walls, the inner cylindrical wall being coated by a catalyst and surrounding the heat pipe. The modular cartridge decomposer provides high thermal efficiency, high conversion efficiency, and increased safety.
Optimal decomposable witnesses without the spanning property
NASA Astrophysics Data System (ADS)
Augusiak, Remigiusz; Sarbicki, Gniewomir; Lewenstein, Maciej
2011-11-01
One of the unsolved problems in the characterization of the optimal entanglement witnesses is the existence of optimal witnesses acting on bipartite Hilbert spaces Hm,n=Cm⊗Cn such that the product vectors obeying
Optimal decomposable witnesses without the spanning property
Augusiak, Remigiusz; Sarbicki, Gniewomir; Lewenstein, Maciej
2011-11-15
One of the unsolved problems in the characterization of the optimal entanglement witnesses is the existence of optimal witnesses acting on bipartite Hilbert spaces H{sub m,n}=C{sup m} x C{sup n} such that the product vectors obeying
Integer sparse distributed memory: analysis and results.
Snaider, Javier; Franklin, Stan; Strain, Steve; George, E Olusegun
2013-10-01
Sparse distributed memory is an auto-associative memory system that stores high dimensional Boolean vectors. Here we present an extension of the original SDM, the Integer SDM that uses modular arithmetic integer vectors rather than binary vectors. This extension preserves many of the desirable properties of the original SDM: auto-associativity, content addressability, distributed storage, and robustness over noisy inputs. In addition, it improves the representation capabilities of the memory and is more robust over normalization. It can also be extended to support forgetting and reliable sequence storage. We performed several simulations that test the noise robustness property and capacity of the memory. Theoretical analyses of the memory's fidelity and capacity are also presented. PMID:23747569
Signature Wood Modifications Reveal Decomposer Community History
Schilling, Jonathan S.; Kaffenberger, Justin T.; Liew, Feng Jin; Song, Zewei
2015-01-01
Correlating plant litter decay rates with initial tissue traits (e.g. C, N contents) is common practice, but in woody litter, predictive relationships are often weak. Variability in predicting wood decomposition is partially due to territorial competition among fungal decomposers that, in turn, have a range of nutritional strategies (rot types) and consequences on residues. Given this biotic influence, researchers are increasingly using culture-independent tools in an attempt to link variability more directly to decomposer groups. Our goal was to complement these tools by using certain wood modifications as ‘signatures’ that provide more functional information about decomposer dominance than density loss. Specifically, we used dilute alkali solubility (DAS; higher for brown rot) and lignin:density loss (L:D; higher for white rot) to infer rot type (binary) and fungal nutritional mode (gradient), respectively. We first determined strength of pattern among 29 fungi of known rot type by correlating DAS and L:D with mass loss in birch and pine. Having shown robust relationships for both techniques above a density loss threshold, we then demonstrated and resolved two issues relevant to species consortia and field trials, 1) spatial patchiness creating gravimetric bias (density bias), and 2) brown rot imprints prior or subsequent to white rot replacement (legacy effects). Finally, we field-tested our methods in a New Zealand Pinus radiata plantation in a paired-plot comparison. Overall, results validate these low-cost techniques that measure the collective histories of decomposer dominance in wood. The L:D measure also showed clear potential in classifying ‘rot type’ along a spectrum rather than as a traditional binary type (brown versus white rot), as it places the nutritional strategies of wood-degrading fungi on a scale (L:D=0-5, in this case). These information-rich measures of consequence can provide insight into their biological causes, strengthening the
A Structural Connection between Linear and 0-1 Integer Linear Formulations
ERIC Educational Resources Information Center
Adlakha, V.; Kowalski, K.
2007-01-01
The connection between linear and 0-1 integer linear formulations has attracted the attention of many researchers. The main reason triggering this interest has been an availability of efficient computer programs for solving pure linear problems including the transportation problem. Also the optimality of linear problems is easily verifiable…
Domain-decomposed preconditionings for transport operators
NASA Technical Reports Server (NTRS)
Chan, Tony F.; Gropp, William D.; Keyes, David E.
1991-01-01
The performance was tested of five different interface preconditionings for domain decomposed convection diffusion problems, including a novel one known as the spectral probe, while varying mesh parameters, Reynolds number, ratio of subdomain diffusion coefficients, and domain aspect ratio. The preconditioners are representative of the range of practically computable possibilities that have appeared in the domain decomposition literature for the treatment of nonoverlapping subdomains. It is shown that through a large number of numerical examples that no single preconditioner can be considered uniformly superior or uniformly inferior to the rest, but that knowledge of particulars, including the shape and strength of the convection, is important in selecting among them in a given problem.
Unconventional integer quantum Hall effect in graphene.
Gusynin, V P; Sharapov, S G
2005-09-30
Monolayer graphite films, or graphene, have quasiparticle excitations that can be described by (2+1)-dimensional Dirac theory. We demonstrate that this produces an unconventional form of the quantized Hall conductivity sigma(xy) = -(2e2/h)(2n+1) with n = 0, 1, ..., which notably distinguishes graphene from other materials where the integer quantum Hall effect was observed. This unconventional quantization is caused by the quantum anomaly of the n=0 Landau level and was discovered in recent experiments on ultrathin graphite films.
An antimalarial stilbene from Artocarpus integer.
Boonlaksiri, C; Oonanant, W; Kongsaeree, P; Kittakoop, P; Tanticharoen, M; Thebtaranonth, Y
2000-06-01
Antimalarial activity-guided study of the aerial parts of Artocarpus integer led to the isolation of the prenylated stilbene, trans-4-(3-methyl-E-but-1-enyl)-3,5,2',4'-tetrahydroxystilbene with an EC50 of 1.7 micrograms/ml against Plasmodium falciparum in culture. The known stilbenes, trans-4-isopentenyl-3,5,2',4'-tetrahydroxystilbene and 4-methoxy-2,2-dimethyl-6-(2-(2,4-dihydroxy)phenyl-trans-ethenyl)chromene , were also isolated. Structures of these compounds were deduced on the basis of their spectral data.
How Powerful Are Integer-Valued Martingales?
NASA Astrophysics Data System (ADS)
Bienvenu, Laurent; Stephan, Frank; Teutsch, Jason
In the theory of algorithmic randomness, one of the central notions is that of computable randomness. An infinite binary sequence X is computably random if no recursive martingale (strategy) can win an infinite amount of money by betting on the values of the bits of X. In the classical model, the martingales considered are real-valued, that is, the bets made by the martingale can be arbitrary real numbers. In this paper, we investigate a more restricted model, where only integer-valued martingales are considered, and we study the class of random sequences induced by this model.
Decomposing Solid Micropropulsion Nozzle Performance Issues
NASA Technical Reports Server (NTRS)
Reed, Brian
2003-01-01
Micropropulsion technology is essential to the success of miniaturized spacecraft and can provide ultra-precise propulsion for small spacecraft. NASA Glenn Research Center has envisioned a micropropulsion concept that utilizes decomposing solid propellants for a valveless, leak-free propulsion system. Among the technical challenges of this decomposing solid micropropulsion concept is optimization of miniature, rectangular nozzles. A number of flat micronozzles were tested with ambient-temperature nitrogen and helium gas in a vacuum facility. The thrusters were etched out of silicon and had throat widths on the order of 350 microns and throat depths on the order of 250 microns. While these were half-sections of thrusters (two would be bonded together before firing), testing provided the performance trend for nozzles of this scale and geometry. Area ratios from 1 to 25 were tested, with thrust measured using an inverted pendulum thrust stand for nitrogen flows and a torsional thrust stand for helium. In the nitrogen testing, peak nozzle performance was achieved around area ratio of 5. In the helium series, nozzle performance peaked for the smallest nozzle tested area ratio 1.5. For both gases, there was a secondary performance peak above area ratio 15. At low chamber pressures (< 1.6 atm), nitrogen provided higher nozzle performance than helium. The performance curve for helium was steeper, however, and it appeared that helium would provide better performance than nitrogen at higher chamber pressures.
Scalable Domain Decomposed Monte Carlo Particle Transport
NASA Astrophysics Data System (ADS)
O'Brien, Matthew Joseph
In this dissertation, we present the parallel algorithms necessary to run domain decomposed Monte Carlo particle transport on large numbers of processors (millions of processors). Previous algorithms were not scalable, and the parallel overhead became more computationally costly than the numerical simulation. The main algorithms we consider are: • Domain decomposition of constructive solid geometry: enables extremely large calculations in which the background geometry is too large to fit in the memory of a single computational node. • Load Balancing: keeps the workload per processor as even as possible so the calculation runs efficiently. • Global Particle Find: if particles are on the wrong processor, globally resolve their locations to the correct processor based on particle coordinate and background domain. • Visualizing constructive solid geometry, sourcing particles, deciding that particle streaming communication is completed and spatial redecomposition. These algorithms are some of the most important parallel algorithms required for domain decomposed Monte Carlo particle transport. We demonstrate that our previous algorithms were not scalable, prove that our new algorithms are scalable, and run some of the algorithms up to 2 million MPI processes on the Sequoia supercomputer.
Process for decomposing nitrates in aqueous solution
Haas, Paul A.
1980-01-01
This invention is a process for decomposing ammonium nitrate and/or selected metal nitrates in an aqueous solution at an elevated temperature and pressure. Where the compound to be decomposed is a metal nitrate (e.g., a nuclear-fuel metal nitrate), a hydroxylated organic reducing agent therefor is provided in the solution. In accordance with the invention, an effective proportion of both nitromethane and nitric acid is incorporated in the solution to accelerate decomposition of the ammonium nitrate and/or selected metal nitrate. As a result, decomposition can be effected at significantly lower temperatures and pressures, permitting the use of system components composed of off-the-shelf materials, such as stainless steel, rather than more costly materials of construction. Preferably, the process is conducted on a continuous basis. Fluid can be automatically vented from the reaction zone as required to maintain the operating temperature at a moderate value--e.g., at a value in the range of from about 130.degree.-200.degree. C.
Horizontal visibility graphs from integer sequences
NASA Astrophysics Data System (ADS)
Lacasa, Lucas
2016-09-01
The horizontal visibility graph (HVG) is a graph-theoretical representation of a time series and builds a bridge between dynamical systems and graph theory. In recent years this representation has been used to describe and theoretically compare different types of dynamics and has been applied to characterize empirical signals, by extracting topological features from the associated HVGs which have shown to be informative on the class of dynamics. Among some other measures, it has been shown that the degree distribution of these graphs is a very informative feature that encapsulates nontrivial information of the series's generative dynamics. In particular, the HVG associated to a bi-infinite real-valued series of independent and identically distributed random variables is a universal exponential law P(k)=(1/3){(2/3)}k-2, independent of the series marginal distribution. Most of the current applications have however only addressed real-valued time series, as no exact results are known for the topological properties of HVGs associated to integer-valued series. In this paper we explore this latter situation and address univariate time series where each variable can only take a finite number n of consecutive integer values. We are able to construct an explicit formula for the parametric degree distribution {P}n(k), which we prove to converge to the continuous case for large n and deviates otherwise. A few applications are then considered.
Supporting Knowledge Transfer through Decomposable Reasoning Artifacts
Pike, William A.; May, Richard A.; Turner, Alan E.
2007-01-03
Technology to support knowledge transfer and cooperative inquiry must offer its users the ability to effectively interpret knowledge structures produced by collaborators. Communicating the reasoning processes that underlie a finding is one method for enhancing interpretation, and can result in more effective evaluation and application of shared knowledge. In knowledge management tools, interpretation is aided by creating knowledge artifacts that can expose their provenance to scrutiny and that can be transformed into diverse representations that suit their consumers’ perspectives and preferences. We outline the information management needs of inquiring communities characterized by hypothesis generation tasks, and propose a model for communication, based in theories of hermeneutics, semiotics, and abduction, in which knowledge structures can be decomposed into the lower-level reasoning artifacts that produced them. We then present a proof-of-concept implementation for an environment to support the capture and communication of analytic products, with emphasis on the domain of intelligence analysis.
Decomposing the stock market intraday dynamics
NASA Astrophysics Data System (ADS)
Kwapień, J.; Drożdż, S.; Grümmer, F.; Ruf, F.; Speth, J.
2002-06-01
The correlation matrix formalism is used to study temporal aspects of the stock market evolution. This formalism allows to decompose the financial dynamics into noise as well as into some coherent repeatable intraday structures. The present study is based on the high-frequency Deutsche Aktienindex (DAX) data over the time period between November 1997 and September 1999, and makes use of both the corresponding returns as well as volatility variations. One principal conclusion is that a bulk of the stock market dynamics is governed by the uncorrelated noise-like processes. There exists, however, a small number of components of coherent short-term repeatable structures in fluctuations that may generate some memory effects seen in the standard autocorrelation function analysis. Laws that govern fluctuations associated with those various components are different, which indicates an extremely complex character of the financial fluctuations.
Camera placement in integer lattices (extended abstract)
NASA Astrophysics Data System (ADS)
Pocchiola, Michel; Kranakis, Evangelos
1990-09-01
Techniques for studying an art gallery problem (the camera placement problem) in the infinite lattice (L sup d) of d tuples of integers are considered. A lattice point A is visible from a camera C positioned at a vertex of (L sup d) if A does not equal C and if the line segment joining A and C crosses no other lattice vertex. By using a combination of probabilistic, combinatorial optimization and algorithmic techniques the position they must occupy in the lattice (L sup d) in the order to maximize their visibility can be determined in polynomial time, for any given number s less than or equal to (5 sup d) of cameras. This improves previous results for s less than or equal to (3 sup d).
Resonance and Revivals in Quantum Rotors: Comparing Half-Integer Spin and Integer Spin
NASA Astrophysics Data System (ADS)
Li, Alvason Zhenhua; Harter, William G.
2013-06-01
Quantum rotor wavefunctions based upon Wigner-D matrix are applied to investigate the quantum resonance and revivals that occur in experimentally accessible spin systems. Interesting physical effects in quantum rotors between half-integer spin and integer spin systems will be discussed to show effects of symmetry. This study will pave the way for more rich dynamic behaviors in asymmetric top that include dynamic tunneling between various equivalent energy surface topography for asymmetric quantum rotors. A key point is that the quantum revivals in the rotor systems exhibit number-information aspects of surprisingly simple Farey-sum and Ford-circle geometry. Such quantum dynamic might have applications for quantum information processing and quantum computing.
Decomposability and mental representation of French verbs
Estivalet, Gustavo L.; Meunier, Fanny E.
2015-01-01
In French, regardless of stem regularity, inflectional verbal suffixes are extremely regular and paradigmatic. Considering the complexity of the French verbal system, we argue that all French verbs are polymorphemic forms that are decomposed during visual recognition independently of their stem regularity. We conducted a behavioral experiment in which we manipulated the surface and cumulative frequencies of verbal inflected forms and asked participants to perform a visual lexical decision task. We tested four types of verbs with respect to their stem variants: a. fully regular (parler “to speak,” [parl-]); b. phonological change e/E verbs with orthographic markers (répéter “to repeat,” [répét-] and [répèt-]); c. phonological change o/O verbs without orthographic markers (adorer “to adore,” [ador-] and [adOr-]); and d. idiosyncratic (boire “to drink,” [boi-] and [buv-]). For each type of verb, we contrasted four conditions, forms with high and low surface frequencies and forms with high and low cumulative frequencies. Our results showed a significant cumulative frequency effect for the fully regular and idiosyncratic verbs, indicating that different stems within idiosyncratic verbs (such as [boi-] and [buv-]) have distinct representations in the mental lexicon as different fully regular verbs. For the phonological change verbs, we found a significant cumulative frequency effect only when considering the two forms of the stem together ([répét-] and [répèt-]), suggesting that they share a single abstract and under specified phonological representation. Our results also revealed a significant surface frequency effect for all types of verbs, which may reflect the recombination of the stem lexical representation with the functional information of the suffixes. Overall, these results indicate that all inflected verbal forms in French are decomposed during visual recognition and that this process could be due to the regularities of the French
A Paper-and-Pencil gcd Algorithm for Gaussian Integers
ERIC Educational Resources Information Center
Szabo, Sandor
2005-01-01
As with natural numbers, a greatest common divisor of two Gaussian (complex) integers "a" and "b" is a Gaussian integer "d" that is a common divisor of both "a" and "b". This article explores an algorithm for such gcds that is easy to do by hand.
A Proposed Instructional Theory for Integer Addition and Subtraction
ERIC Educational Resources Information Center
Stephan, Michelle; Akyuz, Didem
2012-01-01
This article presents the results of a 7th-grade classroom teaching experiment that supported students' understanding of integer addition and subtraction. The experiment was conducted to test and revise a hypothetical learning trajectory so as to propose a potential instructional theory for integer addition and subtraction. The instructional…
Phase Diagram of a 2-D Plane Rotator Model with Integer and Half-Integer Vortices
NASA Astrophysics Data System (ADS)
de Souza, Adauto J. F.; Landau, D. P.
1996-03-01
A two-dimensional plane rotator spin model is simulated by employing the single cluster embeding Monte Carlo technique and the re-weighting histogram analysis. The system is described by the Hamiltonian^1 \\cal H = -J1 sum_< i,j > Si \\cdot Sj - J2 sum_< i,j > ( Si \\cdot Sj )^2. In adition to the familiar integer vortices, this model possesses half-integer vortex excitations as well. The system exhibits three low-temperature phases which may be identified by the behavior of suitably defined two-point correlation functions. The half- and integer-vortex densities as a function of temperature are calculated for several values of the parameter α = J_2/J_1. The phase boundaries are determined and the nature of the phase transitions is investigated. Research supported in part by the CNPq and the NSF. Permanent address: Departmento de Física e Matemática, Universidade Federal Rural de Pernambuco, 52171-900, Recife, Pernambuco, Brazil ^1 D.H. Lee and G. Grinstein Phys. Rev. Lett. \\underline55, 541, (1985)
Integer quantum Hall effect and correlated disorder
Greshnov, A. A. Zegrya, G. G.
2007-11-15
The effect of the form of the random potential of impurities and defects on the longitudinal {sigma}{sub xx} and Hall {sigma}{sub xy} components of conductivity in the mode of the integer quantum Hall effect is theoretically investigated. It is shown that the width of the Hall conductivity plateau as well as the peak values of the longitudinal conductivity heavily depend on the ratio {lambda}/a{sub H} between the random potential correlation length and the magnetic length. For the first time, it is established that in the case of the short-wavelength potential {lambda} << a{sub H}, the peak values of {sigma}{sub xx}{sup (N)} are directly proportional to the Landau level number N {>=} 1, {sigma}{sub xx} = 0.5Ne{sup 2}/h, whereas the peak values of {sigma}{sub xx}{sup (N)} are independent of the Landau level number in the case of the long-wavelength potential {lambda} >> a{sub H}, and their magnitude is much lower than 0.5e{sup 2}/h. The obtained results are in good agreement with the available experimental data.
The integer quantum hall effect revisited
Michalakis, Spyridon; Hastings, Matthew
2009-01-01
For T - L x L a finite subset of Z{sup 2}, let H{sub o} denote a Hamiltonian on T with periodic boundary conditions and finite range, finite strength intetactions and a unique ground state with a nonvanishing spectral gap. For S {element_of} T, let q{sub s} denote the charge at site s and assume that the total charge Q = {Sigma}{sub s {element_of} T} q{sub s} is conserved. Using the local charge operators q{sub s}, we introduce a boundary magnetic flux in the horizontal and vertical direction and allow the ground state to evolve quasiadiabatically around a square of size one magnetic flux, in flux space. At the end of the evolution we obtain a trivial Berry phase, which we compare, via a method reminiscent of Stokes Theorem. to the Berry phase obtained from an evolution around an exponentially small loop near the origin. As a result, we show, without any averaging assumption, that the Hall conductance is quantized in integer multiples of e{sup 2}/h up to exponentially small corrections of order e{sup -L/{zeta}}, where {zeta}, is a correlation length that depends only on the gap and the range and strength of the interactions.
Integrated boiler, superheater, and decomposer for sulfuric acid decomposition
Moore, Robert; Pickard, Paul S.; Parma, Jr., Edward J.; Vernon, Milton E.; Gelbard, Fred; Lenard, Roger X.
2010-01-12
A method and apparatus, constructed of ceramics and other corrosion resistant materials, for decomposing sulfuric acid into sulfur dioxide, oxygen and water using an integrated boiler, superheater, and decomposer unit comprising a bayonet-type, dual-tube, counter-flow heat exchanger with a catalytic insert and a central baffle to increase recuperation efficiency.
Procedures for Decomposing a Redox Reaction into Half-Reaction
ERIC Educational Resources Information Center
Fishtik, Ilie; Berka, Ladislav H.
2005-01-01
A simple algorithm for a complete enumeration of the possible ways a redox reaction (RR) might be uniquely decomposed into half-reactions (HRs) using the response reactions (RERs) formalism is presented. A complete enumeration of the possible ways a RR may be decomposed into HRs is equivalent to a complete enumeration of stoichiometrically…
The Integer and Fractional Quantum Hall Effects.
NASA Astrophysics Data System (ADS)
Usher, Alan
Available from UMI in association with The British Library. Requires signed TDF. This thesis reports investigations of the electrical conductivity of two-dimensional electron systems in high magnetic fields. Studies of the activated longitudinal conductivity associated with the integer quantum Hall effect reveal a large enhancement of the electronic g-factor, caused by the electron-electron interaction. A similar enhancement is observed in the Landau level separation. The magnetic field dependences of both effects are influenced by sample disorder. The activation data are analysed using three models for the shape of the extended state regions of disorder -broadened Landau levels. Only a small fraction of the electrons are found to occupy extended states. Values of the minimum metallic conductivity of electrons in broadened Landau levels are sample- and electron concentration-dependent. The fractional quantum Hall effect is a property of electrons in an incompressible quantum fluid state. The highest quality samples with low electron concentrations exhibit the effect in the manner predicted by simple theories involving spinless electrons. However, the influence of spin becomes apparent at higher electron concentrations, and in tilted field experiments. The effects of disorder are evident in measurements of the quasiparticle energy gap associated with the fractional quantum Hall effect. The experimental gap energies reported in this thesis are considerably smaller than those of theoretical studies, and they tend to zero at a non-zero magnetic field threshold. Simple theories predict that the fractional quantum Hall effect occurs only at odd denominator fractional occupancies. This thesis reports the first observations of the even denominator fractional quantum Hall effect. Persistent photoconductivity is a useful tool for increasing the concentration of two-dimensional electrons in GaAs-AlGaAs heterojunctions. A new photodeexcitation effect is reported, and possible
Adaptive Source Coding Schemes for Geometrically Distributed Integer Alphabets
NASA Technical Reports Server (NTRS)
Cheung, K-M.; Smyth, P.
1993-01-01
Revisit the Gallager and van Voorhis optimal source coding scheme for geometrically distributed non-negative integer alphabets and show that the various subcodes in the popular Rice algorithm can be derived from the Gallager and van Voorhis code.
Fractal electrodynamics via non-integer dimensional space approach
NASA Astrophysics Data System (ADS)
Tarasov, Vasily E.
2015-09-01
Using the recently suggested vector calculus for non-integer dimensional space, we consider electrodynamics problems in isotropic case. This calculus allows us to describe fractal media in the framework of continuum models with non-integer dimensional space. We consider electric and magnetic fields of fractal media with charges and currents in the framework of continuum models with non-integer dimensional spaces. An application of the fractal Gauss's law, the fractal Ampere's circuital law, the fractal Poisson equation for electric potential, and equation for fractal stream of charges are suggested. Lorentz invariance and speed of light in fractal electrodynamics are discussed. An expression for effective refractive index of non-integer dimensional space is suggested.
Integer aperture ambiguity resolution based on difference test
NASA Astrophysics Data System (ADS)
Zhang, Jingyu; Wu, Meiping; Li, Tao; Zhang, Kaidong
2015-07-01
Carrier-phase integer ambiguity resolution (IAR) is the key to highly precise, fast positioning and attitude determination with Global Navigation Satellite System (GNSS). It can be seen as the process of estimating the unknown cycle ambiguities of the carrier-phase observations as integers. Once the ambiguities are fixed, carrier phase data will act as the very precise range data. Integer aperture (IA) ambiguity resolution is the combination of acceptance testing and integer ambiguity resolution, which can realize better quality control of IAR. Difference test (DT) is one of the most popular acceptance tests. This contribution will give a detailed analysis about the following properties of IA ambiguity resolution based on DT: 1.
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.
Inhalation of decomposed chlorodifluoromethane (freon-22) and myocardial infarction.
Sjögren, Bengt; Gunnare, Sara; Sandler, Håkan
2002-06-01
After exposure to decomposed chlorodifluoromethane (freon-22), a 65-year-old man developed respiratory symptoms such as cough, blood-stained sputum, and increasing dyspnea. Three weeks later, his family doctor diagnosed infectious bronchitis. Another week later he died due to myocardial infarction. The discussion focuses on an inflammatory process caused by the inhalation of decomposed freon and its possible association with myocardial infarction.
Polynomial-time algorithms for the integer minimal principle for centrosymmetric structures.
Vaia, Anastasia; Sahinidis, Nikolaos V
2005-07-01
The minimal principle for structure determination from single-crystal X-ray diffraction measurements has recently been formulated as an integer linear optimization model for the case of centrosymmetric structures. Solution of this model via established combinatorial branch-and-bound algorithms provides the true global minimum of the minimal principle while operating exclusively in reciprocal space. However, integer programming techniques may require an exponential number of iterations to exhaust the search space. In this paper, a new approach is developed to solve the integer minimal principle to global optimality without requiring the solution of an optimization problem. Instead, properties of the solution of the optimization problem, as observed in a large number of computational experiments, are exploited in order to reduce the optimization formulation to a system of linear equations in the number field of two elements (F(2)). Two specialized Gaussian elimination algorithms are then developed to solve this system of equations in polynomial time in the number of atoms. Computational results on a collection of 38 structures demonstrate that the proposed approach provides very fast and accurate solutions to the phase problem for centrosymmetric structures. This approach also provided much better crystallographic R values than SHELXS for all 38 structures tested. PMID:15972998
Finite pure integer programming algorithms employing only hyperspherically deduced cuts
NASA Technical Reports Server (NTRS)
Young, R. D.
1971-01-01
Three algorithms are developed that may be based exclusively on hyperspherically deduced cuts. The algorithms only apply, therefore, to problems structured so that these cuts are valid. The algorithms are shown to be finite.
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.
Combinatorial therapy discovery using mixed integer linear programming
Pang, Kaifang; Wan, Ying-Wooi; Choi, William T.; Donehower, Lawrence A.; Sun, Jingchun; Pant, Dhruv; Liu, Zhandong
2014-01-01
Motivation: Combinatorial therapies play increasingly important roles in combating complex diseases. Owing to the huge cost associated with experimental methods in identifying optimal drug combinations, computational approaches can provide a guide to limit the search space and reduce cost. However, few computational approaches have been developed for this purpose, and thus there is a great need of new algorithms for drug combination prediction. Results: Here we proposed to formulate the optimal combinatorial therapy problem into two complementary mathematical algorithms, Balanced Target Set Cover (BTSC) and Minimum Off-Target Set Cover (MOTSC). Given a disease gene set, BTSC seeks a balanced solution that maximizes the coverage on the disease genes and minimizes the off-target hits at the same time. MOTSC seeks a full coverage on the disease gene set while minimizing the off-target set. Through simulation, both BTSC and MOTSC demonstrated a much faster running time over exhaustive search with the same accuracy. When applied to real disease gene sets, our algorithms not only identified known drug combinations, but also predicted novel drug combinations that are worth further testing. In addition, we developed a web-based tool to allow users to iteratively search for optimal drug combinations given a user-defined gene set. Availability: Our tool is freely available for noncommercial use at http://www.drug.liuzlab.org/. Contact: zhandong.liu@bcm.edu Supplementary information: Supplementary data are available at Bioinformatics online. PMID:24463180
Non-integer expansion embedding techniques for reversible image watermarking
NASA Astrophysics Data System (ADS)
Xiang, Shijun; Wang, Yi
2015-12-01
This work aims at reducing the embedding distortion of prediction-error expansion (PE)-based reversible watermarking. In the classical PE embedding method proposed by Thodi and Rodriguez, the predicted value is rounded to integer number for integer prediction-error expansion (IPE) embedding. The rounding operation makes a constraint on a predictor's performance. In this paper, we propose a non-integer PE (NIPE) embedding approach, which can proceed non-integer prediction errors for embedding data into an audio or image file by only expanding integer element of a prediction error while keeping its fractional element unchanged. The advantage of the NIPE embedding technique is that the NIPE technique can really bring a predictor into full play by estimating a sample/pixel in a noncausal way in a single pass since there is no rounding operation. A new noncausal image prediction method to estimate a pixel with four immediate pixels in a single pass is included in the proposed scheme. The proposed noncausal image predictor can provide better performance than Sachnev et al.'s noncausal double-set prediction method (where data prediction in two passes brings a distortion problem due to the fact that half of the pixels were predicted with the watermarked pixels). In comparison with existing several state-of-the-art works, experimental results have shown that the NIPE technique with the new noncausal prediction strategy can reduce the embedding distortion for the same embedding payload.
A Polynomial Time, Numerically Stable Integer Relation Algorithm
NASA Technical Reports Server (NTRS)
Ferguson, Helaman R. P.; Bailey, Daivd H.; Kutler, Paul (Technical Monitor)
1998-01-01
Let x = (x1, x2...,xn be a vector of real numbers. X is said to possess an integer relation if there exist integers a(sub i) not all zero such that a1x1 + a2x2 + ... a(sub n)Xn = 0. Beginning in 1977 several algorithms (with proofs) have been discovered to recover the a(sub i) given x. The most efficient of these existing integer relation algorithms (in terms of run time and the precision required of the input) has the drawback of being very unstable numerically. It often requires a numeric precision level in the thousands of digits to reliably recover relations in modest-sized test problems. We present here a new algorithm for finding integer relations, which we have named the "PSLQ" algorithm. It is proved in this paper that the PSLQ algorithm terminates with a relation in a number of iterations that is bounded by a polynomial in it. Because this algorithm employs a numerically stable matrix reduction procedure, it is free from the numerical difficulties, that plague other integer relation algorithms. Furthermore, its stability admits an efficient implementation with lower run times oil average than other algorithms currently in Use. Finally, this stability can be used to prove that relation bounds obtained from computer runs using this algorithm are numerically accurate.
FPGA Implementation of Optimal 3D-Integer DCT Structure for Video Compression.
Jacob, J Augustin; Kumar, N Senthil
2015-01-01
A novel optimal structure for implementing 3D-integer discrete cosine transform (DCT) is presented by analyzing various integer approximation methods. The integer set with reduced mean squared error (MSE) and high coding efficiency are considered for implementation in FPGA. The proposed method proves that the least resources are utilized for the integer set that has shorter bit values. Optimal 3D-integer DCT structure is determined by analyzing the MSE, power dissipation, coding efficiency, and hardware complexity of different integer sets. The experimental results reveal that direct method of computing the 3D-integer DCT using the integer set [10, 9, 6, 2, 3, 1, 1] performs better when compared to other integer sets in terms of resource utilization and power dissipation.
FPGA Implementation of Optimal 3D-Integer DCT Structure for Video Compression
Jacob, J. Augustin; Kumar, N. Senthil
2015-01-01
A novel optimal structure for implementing 3D-integer discrete cosine transform (DCT) is presented by analyzing various integer approximation methods. The integer set with reduced mean squared error (MSE) and high coding efficiency are considered for implementation in FPGA. The proposed method proves that the least resources are utilized for the integer set that has shorter bit values. Optimal 3D-integer DCT structure is determined by analyzing the MSE, power dissipation, coding efficiency, and hardware complexity of different integer sets. The experimental results reveal that direct method of computing the 3D-integer DCT using the integer set [10, 9, 6, 2, 3, 1, 1] performs better when compared to other integer sets in terms of resource utilization and power dissipation. PMID:26601120
FPGA Implementation of Optimal 3D-Integer DCT Structure for Video Compression.
Jacob, J Augustin; Kumar, N Senthil
2015-01-01
A novel optimal structure for implementing 3D-integer discrete cosine transform (DCT) is presented by analyzing various integer approximation methods. The integer set with reduced mean squared error (MSE) and high coding efficiency are considered for implementation in FPGA. The proposed method proves that the least resources are utilized for the integer set that has shorter bit values. Optimal 3D-integer DCT structure is determined by analyzing the MSE, power dissipation, coding efficiency, and hardware complexity of different integer sets. The experimental results reveal that direct method of computing the 3D-integer DCT using the integer set [10, 9, 6, 2, 3, 1, 1] performs better when compared to other integer sets in terms of resource utilization and power dissipation. PMID:26601120
Comparison of penalty functions on a penalty approach to mixed-integer optimization
NASA Astrophysics Data System (ADS)
Francisco, Rogério B.; Costa, M. Fernanda P.; Rocha, Ana Maria A. C.; Fernandes, Edite M. G. P.
2016-06-01
In this paper, we present a comparative study involving several penalty functions that can be used in a penalty approach for globally solving bound mixed-integer nonlinear programming (bMIMLP) problems. The penalty approach relies on a continuous reformulation of the bMINLP problem by adding a particular penalty term to the objective function. A penalty function based on the `erf' function is proposed. The continuous nonlinear optimization problems are sequentially solved by the population-based firefly algorithm. Preliminary numerical experiments are carried out in order to analyze the quality of the produced solutions, when compared with other penalty functions available in the literature.
Decomposed gosling feet provide evidence of insecticide exposure
Vyas, N.B.; Spann, J.W.; Hulse, C.S.; Torrez, M.; Williams, B.I.; Leffel, R.
2004-01-01
Canada goose goslings were exposed to turf sprayed with D.Z.N(R) diazinon 50W application (2.24 kg a.i./ha). The control plot was subjected to a water application. One foot from each bird was placed outdoors for 7 d to decompose and the other foot was kept frozen. Diazinon residues were analyzed on both feet. Results showed that diazinon was detected from undecomposed and decomposed feet of the birds. Diazinon residues were below the level of detection (<0.01 ppm, a.i.) on the feet from the control goslings. Decomposed feet may be used for determining insecticide exposure when the traditional matrices are not available.
Exploring the Sums of Powers of Consecutive q-Integers
ERIC Educational Resources Information Center
Kim, T.; Ryoo, C. S.; Jang, L. C.; Rim, S. H.
2005-01-01
The Bernoulli numbers are among the most interesting and important number sequences in mathematics. They first appeared in the posthumous work "Ars Conjectandi" (1713) by Jacob Bernoulli (1654-1705) in connection with sums of powers of consecutive integers (Bernoulli, 1713; or Smith, 1959). Bernoulli numbers are particularly important in number…
Informing Practice: Making Sense of Integers through Storytelling
ERIC Educational Resources Information Center
Wessman-Enzinger, Nicole M.; Mooney, Edward S.
2014-01-01
The authors asked fifth-grade and eighth-grade students to pose stories for number sentences involving the addition and subtraction of integers. In this article, the authors look at eight stories from students. Which of these stories works for the given number sentence? What do they reveal about student thinking? When the authors examined these…
Automorphisms of semigroups of invertible matrices with nonnegative integer elements
Semenov, Pavel P
2012-09-30
Let G{sub n}(Z) be the subsemigroup of GL{sub n}(Z) consisting of the matrices with nonnegative integer coefficients. In the paper, the automorphisms of this semigroup are described for n{>=}2. Bibliography: 5 titles.
Using Set Model for Learning Addition of Integers
ERIC Educational Resources Information Center
Lestari, Umi Puji; Putri, Ratu Ilma Indra; Hartono, Yusuf
2015-01-01
This study aims to investigate how set model can help students' understanding of addition of integers in fourth grade. The study has been carried out to 23 students and a teacher of IVC SD Iba Palembang in January 2015. This study is a design research that also promotes PMRI as the underlying design context and activity. Results showed that the…
Triangular Numbers, Gaussian Integers, and KenKen
ERIC Educational Resources Information Center
Watkins, John J.
2012-01-01
Latin squares form the basis for the recreational puzzles sudoku and KenKen. In this article we show how useful several ideas from number theory are in solving a KenKen puzzle. For example, the simple notion of triangular number is surprisingly effective. We also introduce a variation of KenKen that uses the Gaussian integers in order to…
Happy and Sad Thoughts: An Exploration of Children's Integer Reasoning
ERIC Educational Resources Information Center
Whitacre, Ian; Bishop, Jessica Pierson; Lamb, Lisa L. C.; Philipp, Randolph A.; Schappelle, Bonnie P.; Lewis, Melinda L.
2012-01-01
The purpose of this study was to investigate elementary children's conceptions that might serve as foundations for integer reasoning. Working from an abstract algebraic perspective and using an opposite-magnitudes context that is relevant to children, we analyzed the reasoning of 33 children in grades K-5. We focus our report on three prominent…
Negative Integer Understanding: Characterizing First Graders' Mental Models
ERIC Educational Resources Information Center
Bofferding, Laura
2014-01-01
This article presents results of a research study. Sixty-one first graders' responses to interview questions about negative integer values and order and directed magnitudes were examined to characterize the students' mental models. The models reveal that initially, students overrelied on various combinations of whole-number principles as…
Leveraging Structure: Logical Necessity in the Context of Integer Arithmetic
ERIC Educational Resources Information Center
Bishop, Jessica Pierson; Lamb, Lisa L.; Philipp, Randolph A.; Whitacre, Ian; Schappelle, Bonnie P.
2016-01-01
Looking for, recognizing, and using underlying mathematical structure is an important aspect of mathematical reasoning. We explore the use of mathematical structure in children's integer strategies by developing and exemplifying the construct of logical necessity. Students in our study used logical necessity to approach and use numbers in a…
Unique Factorization in Cyclotomic Integers of Degree Seven
ERIC Educational Resources Information Center
Duckworth, W. Ethan
2008-01-01
This article provides a survey of some basic results in algebraic number theory and applies this material to prove that the cyclotomic integers generated by a seventh root of unity are a unique factorization domain. Part of the proof uses the computer algebra system Maple to find and verify factorizations. The proofs use a combination of historic…
Catalytic activities of zeolite compounds for decomposing aqueous ozone.
Kusuda, Ai; Kitayama, Mikito; Ohta, Yoshio
2013-12-01
The advanced oxidation process (AOP), chemical oxidation using aqueous ozone in the presence of appropriate catalysts to generate highly reactive oxygen species, offers an attractive option for removing poorly biodegradable pollutants. Using the commercial zeolite powders with various Si/Al ratios and crystal structures, their catalytic activities for decomposing aqueous ozone were evaluated by continuously flowing ozone to water containing the zeolite powders. The hydrophilic zeolites (low Si/Al ratio) with alkali cations in the crystal structures were found to possess high catalytic activity for decomposing aqueous ozone. The hydrophobic zeolite compounds (high Si/Al ratio) were found to absorb ozone very well, but to have no catalytic activity for decomposing aqueous ozone. Their catalytic activities were also evaluated by using the fixed bed column method. When alkali cations were removed by acid rinsing or substituted by alkali-earth cations, the catalytic activities was significantly deteriorated. These results suggest that the metal cations on the crystal surface of the hydrophilic zeolite would play a key role for catalytic activity for decomposing aqueous ozone.
Catalytic activities of zeolite compounds for decomposing aqueous ozone.
Kusuda, Ai; Kitayama, Mikito; Ohta, Yoshio
2013-12-01
The advanced oxidation process (AOP), chemical oxidation using aqueous ozone in the presence of appropriate catalysts to generate highly reactive oxygen species, offers an attractive option for removing poorly biodegradable pollutants. Using the commercial zeolite powders with various Si/Al ratios and crystal structures, their catalytic activities for decomposing aqueous ozone were evaluated by continuously flowing ozone to water containing the zeolite powders. The hydrophilic zeolites (low Si/Al ratio) with alkali cations in the crystal structures were found to possess high catalytic activity for decomposing aqueous ozone. The hydrophobic zeolite compounds (high Si/Al ratio) were found to absorb ozone very well, but to have no catalytic activity for decomposing aqueous ozone. Their catalytic activities were also evaluated by using the fixed bed column method. When alkali cations were removed by acid rinsing or substituted by alkali-earth cations, the catalytic activities was significantly deteriorated. These results suggest that the metal cations on the crystal surface of the hydrophilic zeolite would play a key role for catalytic activity for decomposing aqueous ozone. PMID:25078817
Dust to dust - How a human corpse decomposes
Vass, Arpad Alexander
2010-01-01
After death, the human body decomposes through four stages. The final, skeleton stage may be reached as quickly as two weeks or as slowly as two years, depending on temperature, humidity and other environmental conditions where the body lies. Dead bodies emit a surprising array of chemicals, from benzene to freon, which can help forensic scientists find clandestine graves.
[Allelopathy of decomposing pepper stalk on pepper growth].
Hou, Yongxia; Zhou, Baoli; Wu, Xiaoling; Fu, Yawen; Wang, Yueying
2006-04-01
With decomposing pepper stalk as test material, this paper studied its allelopathy on the growth of pepper plants. The results showed that after 60 days of decomposition, the decomposed pepper stalk could decrease the plant height, stem diameter, dry weights of above-and underground biomass, leaf area, and chlorophyll content of pepper plants by 0.0374 - 0.0646, 0.0020 - 0.0097, 0.0050 - 0.0355 and 0.0916 - 0.3584, 0.0016 - 0.0251, and 0.0043 - 0.0242 respectively. These inhibitory effects were enhanced after 120 days of decomposition, but the difference with CK was not significant. The root vigor and its SOD, POD and CAT activities of pepper plants were decreased, while the MDA content and relative conductivity were increased with the increasing concentration of decomposed pepper stalk and with the prolong of treating time. The allelopathic effects of decomposed pepper stalk on the physiological indices of pepper root activity ranged from 0.0163 to 0.6507, which was significantly higher than that of plant growth index.
RSM 1.0 user's guide: A resupply scheduler using integer optimization
NASA Technical Reports Server (NTRS)
Viterna, Larry A.; Green, Robert D.; Reed, David M.
1991-01-01
The Resupply Scheduling Model (RSM) is a PC based, fully menu-driven computer program. It uses integer programming techniques to determine an optimum schedule to replace components on or before a fixed replacement period, subject to user defined constraints such as transportation mass and volume limits or available repair crew time. Principal input for RSJ includes properties such as mass and volume and an assembly sequence. Resource constraints are entered for each period corresponding to the component properties. Though written to analyze the electrical power system on the Space Station Freedom, RSM is quite general and can be used to model the resupply of almost any system subject to user defined resource constraints. Presented here is a step by step procedure for preparing the input, performing the analysis, and interpreting the results. Instructions for installing the program and information on the algorithms are given.
A Note on the Visibility in the [1, N ] x [1, N ] Integer Domain
ERIC Educational Resources Information Center
Kim, G. D.; Engelhardt, J.
2007-01-01
A k-dimensional integer point is called visible if the line segment joining the point and the origin contains no proper integer points. This note proposes an explicit formula that represents the number of visible points on the two-dimensional [1,N]x[1,N] integer domain. Simulations and theoretical work are presented. (Contains 5 figures and 2…
Integer-ambiguity resolution in astronomy and geodesy
NASA Astrophysics Data System (ADS)
Lannes, A.; Prieur, J.-L.
2014-02-01
Recent theoretical developments in astronomical aperture synthesis have revealed the existence of integer-ambiguity problems. Those problems, which appear in the self-calibration procedures of radio imaging, have been shown to be similar to the nearest-lattice point (NLP) problems encountered in high-precision geodetic positioning and in global navigation satellite systems. In this paper we analyse the theoretical aspects of the matter and propose new methods for solving those NLP~problems. The related optimization aspects concern both the preconditioning stage, and the discrete-search stage in which the integer ambiguities are finally fixed. Our algorithms, which are described in an explicit manner, can easily be implemented. They lead to substantial gains in the processing time of both stages. Their efficiency was shown via intensive numerical tests.
Anomalous resistance overshoot in the integer quantum Hall effect
Kendirlik, E. M.; Sirt, S.; Kalkan, S. B.; Dietsche, W.; Wegscheider, W.; Ludwig, S.; Siddiki, A.
2013-01-01
In this work we report on experiments performed on smooth edge-narrow Hall bars. The magneto-transport properties of intermediate mobility two-dimensional electron systems are investigated and analyzed within the screening theory of the integer quantized Hall effect. We observe a non-monotonic increase of Hall resistance at the low magnetic field ends of the quantized plateaus, known as the overshoot effect. Unexpectedly, for Hall bars that are defined by shallow chemical etching the overshoot effect becomes more pronounced at elevated temperatures. We observe the overshoot effect at odd and even integer plateaus, which favor a spin independent explanation, in contrast to discussion in the literature. In a second set of the experiments, we investigate the overshoot effect in gate defined Hall bar and explicitly show that the amplitude of the overshoot effect can be directly controlled by gate voltages. We offer a comprehensive explanation based on scattering between evanescent incompressible channels. PMID:24190162
Anomalous resistance overshoot in the integer quantum Hall effect.
Kendirlik, E M; Sirt, S; Kalkan, S B; Dietsche, W; Wegscheider, W; Ludwig, S; Siddiki, A
2013-01-01
In this work we report on experiments performed on smooth edge-narrow Hall bars. The magneto-transport properties of intermediate mobility two-dimensional electron systems are investigated and analyzed within the screening theory of the integer quantized Hall effect. We observe a non-monotonic increase of Hall resistance at the low magnetic field ends of the quantized plateaus, known as the overshoot effect. Unexpectedly, for Hall bars that are defined by shallow chemical etching the overshoot effect becomes more pronounced at elevated temperatures. We observe the overshoot effect at odd and even integer plateaus, which favor a spin independent explanation, in contrast to discussion in the literature. In a second set of the experiments, we investigate the overshoot effect in gate defined Hall bar and explicitly show that the amplitude of the overshoot effect can be directly controlled by gate voltages. We offer a comprehensive explanation based on scattering between evanescent incompressible channels.
Two dimensional convolute integers for machine vision and image recognition
NASA Technical Reports Server (NTRS)
Edwards, Thomas R.
1988-01-01
Machine vision and image recognition require sophisticated image processing prior to the application of Artificial Intelligence. Two Dimensional Convolute Integer Technology is an innovative mathematical approach for addressing machine vision and image recognition. This new technology generates a family of digital operators for addressing optical images and related two dimensional data sets. The operators are regression generated, integer valued, zero phase shifting, convoluting, frequency sensitive, two dimensional low pass, high pass and band pass filters that are mathematically equivalent to surface fitted partial derivatives. These operators are applied non-recursively either as classical convolutions (replacement point values), interstitial point generators (bandwidth broadening or resolution enhancement), or as missing value calculators (compensation for dead array element values). These operators show frequency sensitive feature selection scale invariant properties. Such tasks as boundary/edge enhancement and noise or small size pixel disturbance removal can readily be accomplished. For feature selection tight band pass operators are essential. Results from test cases are given.
Optimal source codes for geometrically distributed integer alphabets
NASA Technical Reports Server (NTRS)
Gallager, R. G.; Van Voorhis, D. C.
1975-01-01
An approach is shown for using the Huffman algorithm indirectly to prove the optimality of a code for an infinite alphabet if an estimate concerning the nature of the code can be made. Attention is given to nonnegative integers with a geometric probability assignment. The particular distribution considered arises in run-length coding and in encoding protocol information in data networks. Questions of redundancy of the optimal code are also investigated.
Population transfer HMQC for half-integer quadrupolar nuclei
Wang, Qiang; Xu, Jun; Feng, Ningdong; Deng, Feng E-mail: jean-paul.amoureux@univ-lille1.fr; Li, Yixuan; Trébosc, Julien; Lafon, Olivier; Hu, Bingwen; Chen, Qun; Amoureux, Jean-Paul E-mail: jean-paul.amoureux@univ-lille1.fr
2015-03-07
This work presents a detailed analysis of a recently proposed nuclear magnetic resonance method [Wang et al., Chem. Commun. 49(59), 6653-6655 (2013)] for accelerating heteronuclear coherence transfers involving half-integer spin quadrupolar nuclei by manipulating their satellite transitions. This method, called Population Transfer Heteronuclear Multiple Quantum Correlation (PT-HMQC), is investigated in details by combining theoretical analyses, numerical simulations, and experimental investigations. We find that compared to instant inversion or instant saturation, continuous saturation is the most practical strategy to accelerate coherence transfers on half-integer quadrupolar nuclei. We further demonstrate that this strategy is efficient to enhance the sensitivity of J-mediated heteronuclear correlation experiments between two half-integer quadrupolar isotopes (e.g., {sup 27}Al-{sup 17}O). In this case, the build-up is strongly affected by relaxation for small T{sub 2}′ and J coupling values, and shortening the mixing time makes a huge signal enhancement. Moreover, this concept of population transfer can also be applied to dipolar-mediated HMQC experiments. Indeed, on the AlPO{sub 4}-14 sample, one still observes experimentally a 2-fold shortening of the optimum mixing time albeit with no significant signal gain in the {sup 31}P-({sup 27}Al) experiments.
Domain decomposed preconditioners with Krylov subspace methods as subdomain solvers
Pernice, M.
1994-12-31
Domain decomposed preconditioners for nonsymmetric partial differential equations typically require the solution of problems on the subdomains. Most implementations employ exact solvers to obtain these solutions. Consequently work and storage requirements for the subdomain problems grow rapidly with the size of the subdomain problems. Subdomain solves constitute the single largest computational cost of a domain decomposed preconditioner, and improving the efficiency of this phase of the computation will have a significant impact on the performance of the overall method. The small local memory available on the nodes of most message-passing multicomputers motivates consideration of the use of an iterative method for solving subdomain problems. For large-scale systems of equations that are derived from three-dimensional problems, memory considerations alone may dictate the need for using iterative methods for the subdomain problems. In addition to reduced storage requirements, use of an iterative solver on the subdomains allows flexibility in specifying the accuracy of the subdomain solutions. Substantial savings in solution time is possible if the quality of the domain decomposed preconditioner is not degraded too much by relaxing the accuracy of the subdomain solutions. While some work in this direction has been conducted for symmetric problems, similar studies for nonsymmetric problems appear not to have been pursued. This work represents a first step in this direction, and explores the effectiveness of performing subdomain solves using several transpose-free Krylov subspace methods, GMRES, transpose-free QMR, CGS, and a smoothed version of CGS. Depending on the difficulty of the subdomain problem and the convergence tolerance used, a reduction in solution time is possible in addition to the reduced memory requirements. The domain decomposed preconditioner is a Schur complement method in which the interface operators are approximated using interface probing.
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.
Materials study supporting thermochemical hydrogen cycle sulfuric acid decomposer design
NASA Astrophysics Data System (ADS)
Peck, Michael S.
Increasing global climate change has been driven by greenhouse gases emissions originating from the combustion of fossil fuels. Clean burning hydrogen has the potential to replace much of the fossil fuels used today reducing the amount of greenhouse gases released into the atmosphere. The sulfur iodine and hybrid sulfur thermochemical cycles coupled with high temperature heat from advanced nuclear reactors have shown promise for economical large-scale hydrogen fuel stock production. Both of these cycles employ a step to decompose sulfuric acid to sulfur dioxide. This decomposition step occurs at high temperatures in the range of 825°C to 926°C dependent on the catalysis used. Successful commercial implementation of these technologies is dependent upon the development of suitable materials for use in the highly corrosive environments created by the decomposition products. Boron treated diamond film was a potential candidate for use in decomposer process equipment based on earlier studies concluding good oxidation resistance at elevated temperatures. However, little information was available relating the interactions of diamond and diamond films with sulfuric acid at temperatures greater than 350°C. A laboratory scale sulfuric acid decomposer simulator was constructed at the Nuclear Science and Engineering Institute at the University of Missouri-Columbia. The simulator was capable of producing the temperatures and corrosive environments that process equipment would be exposed to for industrialization of the sulfur iodide or hybrid sulfur thermochemical cycles. A series of boron treated synthetic diamonds were tested in the simulator to determine corrosion resistances and suitability for use in thermochemical process equipment. These studies were performed at twenty four hour durations at temperatures between 600°C to 926°C. Other materials, including natural diamond, synthetic diamond treated with titanium, silicon carbide, quartz, aluminum nitride, and Inconel
Integer least-squares theory for the GNSS compass
NASA Astrophysics Data System (ADS)
Teunissen, P. J. G.
2010-07-01
Global navigation satellite system (GNSS) carrier phase integer ambiguity resolution is the key to high-precision positioning and attitude determination. In this contribution, we develop new integer least-squares (ILS) theory for the GNSS compass model, together with efficient integer search strategies. It extends current unconstrained ILS theory to the nonlinearly constrained case, an extension that is particularly suited for precise attitude determination. As opposed to current practice, our method does proper justice to the a priori given information. The nonlinear baseline constraint is fully integrated into the ambiguity objective function, thereby receiving a proper weighting in its minimization and providing guidance for the integer search. Different search strategies are developed to compute exact and approximate solutions of the nonlinear constrained ILS problem. Their applicability depends on the strength of the GNSS model and on the length of the baseline. Two of the presented search strategies, a global and a local one, are based on the use of an ellipsoidal search space. This has the advantage that standard methods can be applied. The global ellipsoidal search strategy is applicable to GNSS models of sufficient strength, while the local ellipsoidal search strategy is applicable to models for which the baseline lengths are not too small. We also develop search strategies for the most challenging case, namely when the curvature of the non-ellipsoidal ambiguity search space needs to be taken into account. Two such strategies are presented, an approximate one and a rigorous, somewhat more complex, one. The approximate one is applicable when the fixed baseline variance matrix is close to diagonal. Both methods make use of a search and shrink strategy. The rigorous solution is efficiently obtained by means of a search and shrink strategy that uses non-quadratic, but easy-to-evaluate, bounding functions of the ambiguity objective function. The theory
NASA Astrophysics Data System (ADS)
Shoemaker, Christine; Wan, Ying
2016-04-01
Optimization of nonlinear water resources management issues which have a mixture of fixed (e.g. construction cost for a well) and variable (e.g. cost per gallon of water pumped) costs has been not well addressed because prior algorithms for the resulting nonlinear mixed integer problems have required many groundwater simulations (with different configurations of decision variable), especially when the solution space is multimodal. In particular heuristic methods like genetic algorithms have often been used in the water resources area, but they require so many groundwater simulations that only small systems have been solved. Hence there is a need to have a method that reduces the number of expensive groundwater simulations. A recently published algorithm for nonlinear mixed integer programming using surrogates was shown in this study to greatly reduce the computational effort for obtaining accurate answers to problems involving fixed costs for well construction as well as variable costs for pumping because of a substantial reduction in the number of groundwater simulations required to obtain an accurate answer. Results are presented for a US EPA hazardous waste site. The nonlinear mixed integer surrogate algorithm is general and can be used on other problems arising in hydrology with open source codes in Matlab and python ("pySOT" in Bitbucket).
GNSS integer ambiguity validation based on posterior probability
NASA Astrophysics Data System (ADS)
Wu, Zemin; Bian, Shaofeng
2015-10-01
GNSS integer ambiguity validation is considered to be a challenge task for decades. Several kinds of validation tests are developed and widely used in these years, but theoretical basis is their weakness. Ambiguity validation theoretically is an issue of hypothesis test. In the frame of Bayesian hypothesis testing, posterior probability is the canonical standard that statistical decision should be based on. In this contribution, (i) we derive the posterior probability of the fixed ambiguity based on the Bayesian principle and modify it for practice ambiguity validation. (ii) The optimal property of the posterior probability test is proved based on an extended Neyman-Pearson lemma. Since validation failure rate is the issue users most concerned about, (iii) we derive the failure rate upper bound of the posterior probability test, so the user can use the posterior probability test either in the fixed posterior probability or in the fixed failure rate way. Simulated as well as real observed data are used for experimental validations. The results show that (i) the posterior probability test is the most effective within the R-ratio test, difference test, ellipsoidal integer aperture test and posterior probability test, (ii) the posterior probability test is computational efficient and (iii) the failure rate estimation for posterior probability test is useful.
A Secret Image Sharing Method Using Integer Wavelet Transform
NASA Astrophysics Data System (ADS)
Huang, Chin-Pan; Li, Ching-Chung
2007-12-01
A new image sharing method, based on the reversible integer-to-integer (ITI) wavelet transform and Shamir's [InlineEquation not available: see fulltext.] threshold scheme is presented, that provides highly compact shadows for real-time progressive transmission. This method, working in the wavelet domain, processes the transform coefficients in each subband, divides each of the resulting combination coefficients into [InlineEquation not available: see fulltext.] shadows, and allows recovery of the complete secret image by using any [InlineEquation not available: see fulltext.] or more shadows [InlineEquation not available: see fulltext.]. We take advantages of properties of the wavelet transform multiresolution representation, such as coefficient magnitude decay and excellent energy compaction, to design combination procedures for the transform coefficients and processing sequences in wavelet subbands such that small shadows for real-time progressive transmission are obtained. Experimental results demonstrate that the proposed method yields small shadow images and has the capabilities of real-time progressive transmission and perfect reconstruction of secret images.
ON THE DISTRIBUTION OF THE GREATEST COMMON DIVISOR OF GAUSSIAN INTEGERS
BRADLEY, TAI-DANAE; CHENG, YIN CHOI; LUO, YAN FEI
2016-01-01
For a pair of random Gaussian integers chosen uniformly and independently from the set of Gaussian integers of norm x or less as x goes to infinity, we find asymptotics for the average norm of their greatest common divisor, with explicit error terms. We also present results for higher moments along with computational data which support the results for the second, third, fourth, and fifth moments. The analogous question for integers is studied by Diaconis and Erdös. PMID:27761199
Tláskal, Vojtěch; Voříšková, Jana; Baldrian, Petr
2016-11-01
The decomposition of dead plant biomass contributes to the carbon cycle and is one of the key processes in temperate forests. While fungi in litter decomposition drive the chemical changes occurring in litter, the bacterial community appears to be important as well, especially later in the decomposition process when its abundance increases. In this paper, we describe the bacterial community composition in live Quercus petraea leaves and during the subsequent two years of litter decomposition. Members of the classes Alpha-, Beta- and Gammaproteobacteria and the phyla Actinobacteria, Bacteroidetes and Acidobacteria were dominant throughout the experiment. Bacteria present in the oak phyllosphere were rapidly replaced by other taxa after leaf senescence. There were dynamic successive changes in community composition, in which the early-stage (months 2-4), mid-stage (months 6-8) and late-stage (months 10-24) decomposer communities could be distinguished, and the diversity increased with time. Bacteria associated with dead fungal mycelium were important during initial decomposition, with sequence relative abundances of up to 40% of the total bacterial community in months 2 and 4 when the highest fungal biomass was observed. Cellulose-decomposing bacteria were less frequent, with abundance ranging from 4% to 15%. The bacterial community dynamics reflects changes in the availability of possible resources either of the plant or microbial origin.
Tláskal, Vojtěch; Voříšková, Jana; Baldrian, Petr
2016-11-01
The decomposition of dead plant biomass contributes to the carbon cycle and is one of the key processes in temperate forests. While fungi in litter decomposition drive the chemical changes occurring in litter, the bacterial community appears to be important as well, especially later in the decomposition process when its abundance increases. In this paper, we describe the bacterial community composition in live Quercus petraea leaves and during the subsequent two years of litter decomposition. Members of the classes Alpha-, Beta- and Gammaproteobacteria and the phyla Actinobacteria, Bacteroidetes and Acidobacteria were dominant throughout the experiment. Bacteria present in the oak phyllosphere were rapidly replaced by other taxa after leaf senescence. There were dynamic successive changes in community composition, in which the early-stage (months 2-4), mid-stage (months 6-8) and late-stage (months 10-24) decomposer communities could be distinguished, and the diversity increased with time. Bacteria associated with dead fungal mycelium were important during initial decomposition, with sequence relative abundances of up to 40% of the total bacterial community in months 2 and 4 when the highest fungal biomass was observed. Cellulose-decomposing bacteria were less frequent, with abundance ranging from 4% to 15%. The bacterial community dynamics reflects changes in the availability of possible resources either of the plant or microbial origin. PMID:27543318
Leaf herbivory and decomposability in a Malaysian tropical rain forest.
Kurokawa, Hiroko; Nakashizuka, Tohru
2008-09-01
There is accumulating evidence that similar suites of plant traits may affect leaf palatability and leaf litter decomposability. However, the possible association between leaf herbivory and litter decomposition rates across species in species-diverse natural ecosystems such as tropical rain forests remains unexplored, despite its importance in estimating the herbivory effects on carbon and nutrient cycling of ecosystems. We found no strong association between leaf herbivory and litter decomposition rates across 40 tree species in a Malaysian tropical rain forest, even though the leaf and litter traits were tightly correlated. This is because the leaf and litter traits related to herbivory and decomposition rates in the field were inconsistent. Leaf toughness accounted for only a small part of the variation in the herbivory rate, whereas a number of litter traits (the leaf mass per area, lignin to nitrogen ratio, and condensed tannin concentration) accurately predicted the decomposition rate across species. These results suggest that herbivory rate across species may not be strongly related to single leaf traits, probably because plant-herbivore interactions in tropical rain forests are highly diverse; on the other hand, plant-decomposer interactions are less specific and can be governed by litter chemicals. We also investigated two factors, phylogeny and tree functional types, that could affect the relationship between herbivory and decomposition across species. Phylogenetic relatedness among the species did not affect the relationship between herbivory and decomposition. In contrast, when the plants were segregated according to their leaf emergence pattern, we found a significant positive relationship between herbivory and decomposition rates for continuous-leafing species. In these species, the condensed tannin to N ratios in leaves and litter were related to herbivory and decomposition rates, respectively. However, we did not observe a similar trend for
'Willpower' over the life span: decomposing self-regulation.
Mischel, Walter; Ayduk, Ozlem; Berman, Marc G; Casey, B J; Gotlib, Ian H; Jonides, John; Kross, Ethan; Teslovich, Theresa; Wilson, Nicole L; Zayas, Vivian; Shoda, Yuichi
2011-04-01
In the 1960s, Mischel and colleagues developed a simple 'marshmallow test' to measure preschoolers' ability to delay gratification. In numerous follow-up studies over 40 years, this 'test' proved to have surprisingly significant predictive validity for consequential social, cognitive and mental health outcomes over the life course. In this article, we review key findings from the longitudinal work and from earlier delay-of-gratification experiments examining the cognitive appraisal and attention control strategies that underlie this ability. Further, we outline a set of hypotheses that emerge from the intersection of these findings with research on 'cognitive control' mechanisms and their neural bases. We discuss implications of these hypotheses for decomposing the phenomena of 'willpower' and the lifelong individual differences in self-regulatory ability that were identified in the earlier research and that are currently being pursued.
Decomposing the Unsteady Flow Routing in River Systems
NASA Astrophysics Data System (ADS)
Gomez Cunya, L. A.; Leon, A.; Gibson, N. L.; Vasylkivska, V.
2014-12-01
This work presents an optimization-based domain decomposition strategy for unsteady flow routing in complex river systems. This strategy couples the domain decomposition technique with a Precomputed Channel Hydraulics Ensemble approach, known also as HydraulicPerformance Graph (HPG), which utilizes precomputed solutions along reaches on a river system. These solutions are stored in a database. While efficient and robust, HPGs requires extensive memory allocation, especially for high resolution simulations. Decomposing the river system into subdomains reduces computer memory constraints as each sub-domain is solved independently. Further, an optimization method is used to couple the sub-domains using the stored precomputed solution. In turn, the computational efficiency of the HPG approach allows the optimization-based scheme to be competitive with a whole domain methodology. The combined strategy is expected to reduce the overall computational time for large-scale problems. This work discusses the results of the application to the Columbia River (Northwest USA).
Fungal community on decomposing leaf litter undergoes rapid successional changes
Voříšková, Jana; Baldrian, Petr
2013-01-01
Fungi are considered the primary decomposers of dead plant biomass in terrestrial ecosystems. However, current knowledge regarding the successive changes in fungal communities during litter decomposition is limited. Here we explored the development of the fungal community over 24 months of litter decomposition in a temperate forest with dominant Quercus petraea using 454-pyrosequencing of the fungal internal transcribed spacer (ITS) region and cellobiohydrolase I (cbhI) genes, which encode exocellulases, to specifically address cellulose decomposers. To quantify the involvement of phyllosphere fungi in litter decomposition, the fungal communities in live leaves and leaves immediately before abscission were also analysed. The results showed rapid succession of fungi with dramatic changes in the composition of the fungal community. Furthermore, most of the abundant taxa only temporarily dominated in the substrate. Fungal diversity was lowest at leaf senescence, increased until month 4 and did not significantly change during subsequent decomposition. Highly diverse community of phyllosphere fungi inhabits live oak leaves 2 months before abscission, and these phyllosphere taxa comprise a significant share of the fungal community during early decomposition up to the fourth month. Sequences assigned to the Ascomycota showed highest relative abundances in live leaves and during the early stages of decomposition. In contrast, the relative abundance of sequences assigned to the Basidiomycota phylum, particularly basidiomycetous yeasts, increased with time. Although cellulose was available in the litter during all stages of decomposition, the community of cellulolytic fungi changed substantially over time. The results indicate that litter decomposition is a highly complex process mediated by various fungal taxa. PMID:23051693
Fungal community on decomposing leaf litter undergoes rapid successional changes.
Voříšková, Jana; Baldrian, Petr
2013-03-01
Fungi are considered the primary decomposers of dead plant biomass in terrestrial ecosystems. However, current knowledge regarding the successive changes in fungal communities during litter decomposition is limited. Here we explored the development of the fungal community over 24 months of litter decomposition in a temperate forest with dominant Quercus petraea using 454-pyrosequencing of the fungal internal transcribed spacer (ITS) region and cellobiohydrolase I (cbhI) genes, which encode exocellulases, to specifically address cellulose decomposers. To quantify the involvement of phyllosphere fungi in litter decomposition, the fungal communities in live leaves and leaves immediately before abscission were also analysed. The results showed rapid succession of fungi with dramatic changes in the composition of the fungal community. Furthermore, most of the abundant taxa only temporarily dominated in the substrate. Fungal diversity was lowest at leaf senescence, increased until month 4 and did not significantly change during subsequent decomposition. Highly diverse community of phyllosphere fungi inhabits live oak leaves 2 months before abscission, and these phyllosphere taxa comprise a significant share of the fungal community during early decomposition up to the fourth month. Sequences assigned to the Ascomycota showed highest relative abundances in live leaves and during the early stages of decomposition. In contrast, the relative abundance of sequences assigned to the Basidiomycota phylum, particularly basidiomycetous yeasts, increased with time. Although cellulose was available in the litter during all stages of decomposition, the community of cellulolytic fungi changed substantially over time. The results indicate that litter decomposition is a highly complex process mediated by various fungal taxa. PMID:23051693
Analytical estimation of the correlation dimension of integer lattices
Lacasa, Lucas; Gómez-Gardeñes, Jesús
2014-12-01
Recently [L. Lacasa and J. Gómez-Gardeñes, Phys. Rev. Lett. 110, 168703 (2013)], a fractal dimension has been proposed to characterize the geometric structure of networks. This measure is an extension to graphs of the so called correlation dimension, originally proposed by Grassberger and Procaccia to describe the geometry of strange attractors in dissipative chaotic systems. The calculation of the correlation dimension of a graph is based on the local information retrieved from a random walker navigating the network. In this contribution, we study such quantity for some limiting synthetic spatial networks and obtain analytical results on agreement with the previously reported numerics. In particular, we show that up to first order, the correlation dimension β of integer lattices ℤ{sup d} coincides with the Haussdorf dimension of their coarsely equivalent Euclidean spaces, β = d.
Fast on-chip mean filter requiring only integer operations
NASA Astrophysics Data System (ADS)
Bhattacharya, Bhargab B.; Biswas, Arindam; Bhowmick, Partha; Acharya, Tinku
2008-01-01
This paper presents a novel formulation of the classical mean filtering, which has been shown to stem from the theory of continued fractions as well as from the rules of binomial expansion. Such an alternative formulation of mean filtering is marked by its sufficiency of only a few primitive operations, namely binary shifts and addition (subtraction), in the integer domain. Subsequently, the resultant process of smoothing a digital image using the mean filter is devoid of any floating-point computation, and can be implemented by a simple hardware, thereof. In addition, the formulation has the ability of yielding an approximate solution using fewer operations, which can bring the hardware cost further down. We have tested our method for various images, and have reported some relevant results to demonstrate its elegance, versatility, and effectiveness, specially when an approximate solution is called for.
Pure scaling operators at the integer quantum Hall plateau transition.
Bondesan, R; Wieczorek, D; Zirnbauer, M R
2014-05-01
Stationary wave functions at the transition between plateaus of the integer quantum Hall effect are known to exhibit multifractal statistics. Here we explore this critical behavior for the case of scattering states of the Chalker-Coddington network model with point contacts. We argue that moments formed from the wave amplitudes of critical scattering states decay as pure powers of the distance between the points of contact and observation. These moments in the continuum limit are proposed to be correlation functions of primary fields of an underlying conformal field theory. We check this proposal numerically by finite-size scaling. We also verify the conformal field theory prediction for a three-point function involving two primary fields.
Non-chiral 2d CFT with integer energy levels
NASA Astrophysics Data System (ADS)
Ashrafi, M.; Loran, F.
2016-09-01
The partition function of 2d conformal field theory is a modular invariant function. It is known that the partition function of a holomorphic CFT whose central charge is a multiple of 24 is a polynomial in the Klein function. In this paper, by using the medium temperature expansion we show that every modular invariant partition function can be mapped to a holomorphic partition function whose structure can be determined similarly. We use this map to study partition function of CFTs with half-integer left and right conformal weights. We show that the corresponding left and right central charges are necessarily multiples of 4. Furthermore, the degree of degeneracy of high-energy levels can be uniquely determined in terms of the degeneracy in the low energy states.
Integer cosine transform chip design for image compression
NASA Astrophysics Data System (ADS)
Ruiz, Gustavo A.; Michell, Juan A.; Buron, Angel M.; Solana, Jose M.; Manzano, Miguel A.; Diaz, J.
2003-04-01
The Discrete Cosine Transform (DCT) is the most widely used transform for image compression. The Integer Cosine Transform denoted ICT (10, 9, 6, 2, 3, 1) has been shown to be a promising alternative to the DCT due to its implementation simplicity, similar performance and compatibility with the DCT. This paper describes the design and implementation of a 8×8 2-D ICT processor for image compression, that meets the numerical characteristic of the IEEE std. 1180-1990. This processor uses a low latency data flow that minimizes the internal memory and a parallel pipelined architecture, based on a numerical strength reduction Integer Cosine Transform (10, 9, 6, 2, 3, 1) algorithm, in order to attain high throughput and continuous data flow. A prototype of the 8×8 ICT processor has been implemented using a standard cell design methodology and a 0.35-μm CMOS CSD 3M/2P 3.3V process on a 10 mm2 die. Pipeline circuit techniques have been used to attain the maximum frequency of operation allowed by the technology, attaining a critical path of 1.8ns, which should be increased by a 20% to allow for line delays, placing the estimated operational frequency at 500Mhz. The circuit includes 12446 cells, being flip-flops 6757 of them. Two clock signals have been distributed, an external one (fs) and an internal one (fs/2). The high number of flip-flops has forced the use of a strategy to minimize clock-skew, combining big sized buffers on the periphery and using wide metal lines (clock-trunks) to distribute the signals.
Integer-spin electron paramagnetic resonance of iron proteins.
Hendrich, M P; Debrunner, P G
1989-01-01
A quantitative interpretation is presented for EPR spectra from integer-spin metal centers having large zero-field splittings. Integer-spin, or non-Kramers, centers are common in metalloproteins and many give EPR signals, but a quantitative understanding has been lacking until now. Heterogeneity of the metal's local environment will result in a significant spread in zero-field splittings and in broadened EPR signals. Using the spin Hamiltonian Hs = S.D.S + beta S.g.B and some simple assumptions about the nature of the zero-field parameter distributions, a lineshape model was devised which allows accurate simulation of single crystal and frozen solution spectra. The model was tested on single crystals of magnetically dilute ferrous fluosilicate. Data and analyses from proteins and active-site models are presented with the microwave field B1 either parallel or perpendicular to B. Quantitative agreement of observed and predicted signal intensities is found for the two B1 orientations. Methods of spin quantitation are given and are shown to predict an unknown concentration relative to a standard with known concentration. The fact that the standard may be either a non-Kramers or a Kramers center is further proof of the model's validity. The magnitude of the splitting in zero magnetic field is of critical importance; it affects not only the chance of signal observation, but also the quantitation accuracy. Experiments taken at microwave frequencies of 9 and 35 GHz demonstrate the need for high-frequency data as only a fraction of the molecules give signals at 9 GHz. PMID:2551404
NASA Technical Reports Server (NTRS)
Schneider, Steven J. (Inventor)
2002-01-01
A reduced toxicity fuel satellite propulsion system including a reduced toxicity propellant supply for consumption in an axial class thruster and an ACS class thruster. The system includes suitable valves and conduits for supplying the reduced toxicity propellant to the ACS decomposing element of an ACS thruster. The ACS decomposing element is operative to decompose the reduced toxicity propellant into hot propulsive gases. In addition the system includes suitable valves and conduits for supplying the reduced toxicity propellant to an axial decomposing element of the axial thruster. The axial decomposing element is operative to decompose the reduced toxicity propellant into hot gases. The system further includes suitable valves and conduits for supplying a second propellant to a combustion chamber of the axial thruster, whereby the hot gases and the second propellant auto-ignite and begin the combustion process for producing thrust.
Decomposing socioeconomic inequalities in childhood obesity: evidence from Ireland.
Walsh, Brendan; Cullinan, John
2015-01-01
The objective of this paper is to quantify and decompose the socioeconomic gradient in childhood obesity in the Republic of Ireland. The analysis is performed using data from the first wave of the Growing Up in Ireland survey, a nationally representative survey of 8568 nine-year-old children conducted in 2007 and 2008. We estimate concentration indices to quantify the extent of the socioeconomic gradient in childhood obesity and undertake a subsequent decomposition analysis to pinpoint the key factors underpinning the observed inequalities. Overall the results confirm a strong socioeconomic gradient in childhood obesity in the Republic of Ireland. Concentration indices of obesity (CI=-0.168) and overweight/obese (CI=-0.057) show that the gradient is more pronounced in obese children, while results from the decomposition analysis suggest that the majority of the inequality in childhood obesity is explained by parental level variables. Our findings suggest that addressing childhood obesity inequalities requires coordinated policy responses at both the child and parental level.
Do chickens (Gallus gallus f. domestica) decompose visual figures?
Werner, Christian W; Tiemann, Inga; Cnotka, Julia; Rehkämper, Gerd
2005-04-01
To investigate whether learning to discriminate between visual compound stimuli depends on decomposing them into constituting features, hens were first trained to discriminate four features (red, green, horizontal, vertical) from two dimensions (colour, line orientation). After acquisition, hens were trained with compound stimuli made up from these dimensions in two ways: a separable (line on a coloured background) stimulus and an integral one (coloured line). This compound training included a reversal of reinforcement of only one of the two dimensions (half-reversal). After having achieved the compound stimulus discrimination, a second dimensional training identical to the first was performed. Finally, in the second compound training the other dimension was reversed. Two major results were found: (1) an interaction between the dimension reversed and the type of compound stimulus: in compound training with colour reversal, separable compound stimuli were discriminated worse than integral compounds and vice versa in compound training with line orientation reversed. (2) Performance in the second compound training was worse than in the first one. The first result points to a similar mode of processing for separable and integral compounds, whereas the second result shows that the whole stimulus is psychologically superior to its constituting features. Experiment 2 repeated experiment 1 using line orientation stimuli of reversed line and background brightness. Nevertheless, the results were similar to experiment 1. Results are discussed in the framework of a configural exemplar theory of discrimination that assumes the representation of the whole stimulus situation combined with transfer based on a measure of overall similarity.
Decomposing the effect of crime on population changes.
Foote, Andrew
2015-04-01
This article estimates the effect of crime on migration rates for counties in U.S. metropolitan areas and makes three contributions to the literature. First, I use administrative data on migration flows between counties, which gives me more precise estimates of population changes than data used in previous studies. Second, I am able to decompose net population changes into gross migration flows in order to identify how individuals respond to crime rate changes. Finally, I include county-level trends so that my identification comes from shocks away from the trend. I find effects that are one-fiftieth the size of the most prominent estimate in the literature; and although the long-run effects are somewhat larger, they are still only approximately one-twentieth as large. I also find that responses to crime rates differ by subgroups, and that increases in crime cause white households to leave the county, with effects almost 10 times as large as for black households.
Toxic effects of decomposing red algae on littoral organisms
NASA Astrophysics Data System (ADS)
Eklund, Britta; Svensson, Andreas P.; Jonsson, Conny; Malm, Torleif
2005-03-01
Large masses of filamentous red algae of the genera Polysiphonia, Rhodomela, and Ceramium are regularly washed up on beaches of the central Baltic Sea. As the algal masses start to decay, red coloured effluents leak into the water, and this tinge may be traced several hundred meters off shore. In this study, possible toxic effects of these effluents were tested on littoral organisms from different trophic levels. Effects on fertilisation, germination and juvenile survival of the brown seaweed Fucus vesiculosus were investigated, and mortality tests were performed on the crustaceans Artemia salina and Idotea baltica, as well as on larvae and adults of the fish Pomatoschistus microps. Fucus vesiculosus was the most sensitive species of the tested organisms to the red algal extract. The survival of F. vesiculosus recruits was reduced with 50% (LC50) when exposed to a concentration corresponding to 1.7 g l -1 dw red algae. The lethal concentration for I. baltica, A. salina and P. microps were approximately ten times higher. The toxicity to A. salina was reduced if the algal extract was left to decompose during two weeks but the decline in toxicity was not affected by different light or temperature conditions. This study indicates that the filamentous red algae in the central Baltic Sea may produce and release compounds with negative effects on the littoral ecosystem. The effects may be particularly serious for the key species F. vesiculosus, which reproduce in autumn when filamentous red algal blooms are most severe.
Improving integer ambiguity resolution for GLONASS precise orbit determination
NASA Astrophysics Data System (ADS)
Liu, Yang; Ge, Maorong; Shi, Chuang; Lou, Yidong; Wickert, Jens; Schuh, Harald
2016-08-01
The frequency division multiple access adopted in present GLONASS introduces inter-frequency bias (IFB) at the receiver-end both in code and phase observables, which makes GLONASS ambiguity resolution rather difficult or even not available, especially for long baselines up to several thousand kilometers. This is one of the major reasons that GLONASS could hardly reach the orbit precision of GPS, both in terms of consistency among individual International GNSS Service (IGS) analysis centers and discontinuity at the overlapping day boundaries. Based on the fact that the GLONASS phase IFB is similar on L1 and L2 bands in unit of length and is a linear function of the frequency number, several approaches have been developed to estimate and calibrate the IFB for integer ambiguity resolution. However, they are only for short and medium baselines. In this study, a new ambiguity resolution approach is developed for GLONASS global networks. In the approach, the phase ambiguities in the ionosphere-free linear combination are directly transformed with a wavelength of about 5.3 cm, according to the special frequency relationship of GLONASS L1 and L2 signals. After such transformation, the phase IFB rate can be estimated and corrected precisely and then the corresponding double-differenced ambiguities can be directly fixed to integers even for baselines up to several thousand kilometers. To evaluate this approach, experimental validations using one-month data of a global network with 140 IGS stations was carried out for GLONASS precise orbit determination. The results show that the GLONASS double-difference ambiguity resolution for long baselines could be achieved with an average fixing-rate of 91.4 %. Applying the fixed ambiguities as constraints, the GLONASS orbit overlapping RMS at the day boundaries could be reduced by 37.2 % in ideal cases and with an averaged reduction of about 21.4 %, which is comparable with that by the GPS ambiguity resolution. The orbit improvement is
ERIC Educational Resources Information Center
Bishop, Jessica Pierson; Lamb, Lisa L.; Philipp, Randolph A.; Whitacre, Ian; Schappelle, Bonnie P.; Lewis, Melinda L.
2014-01-01
We identify and document 3 cognitive obstacles, 3 cognitive affordances, and 1 type of integer understanding that can function as either an obstacle or affordance for learners while they extend their numeric domains from whole numbers to include negative integers. In particular, we highlight 2 key subsets of integer reasoning: understanding or…
Anisotropic fractal media by vector calculus in non-integer dimensional space
Tarasov, Vasily E.
2014-08-15
A review of different approaches to describe anisotropic fractal media is proposed. In this paper, differentiation and integration non-integer dimensional and multi-fractional spaces are considered as tools to describe anisotropic fractal materials and media. We suggest a generalization of vector calculus for non-integer dimensional space by using a product measure method. The product of fractional and non-integer dimensional spaces allows us to take into account the anisotropy of the fractal media in the framework of continuum models. The integration over non-integer-dimensional spaces is considered. In this paper differential operators of first and second orders for fractional space and non-integer dimensional space are suggested. The differential operators are defined as inverse operations to integration in spaces with non-integer dimensions. Non-integer dimensional space that is product of spaces with different dimensions allows us to give continuum models for anisotropic type of the media. The Poisson's equation for fractal medium, the Euler-Bernoulli fractal beam, and the Timoshenko beam equations for fractal material are considered as examples of application of suggested generalization of vector calculus for anisotropic fractal materials and media.
Cho Decomposition of One-Half Integer Monopoles Solutions
NASA Astrophysics Data System (ADS)
Teh, Rosy; Ng, Ban-Loong; Wong, Khai-Ming
2013-11-01
We performed the Cho decomposition of the SU(2) Yang-Mills-Higgs gauge potentials of the finite energy (1) one-half monopole solution and (2) the one and a half monopoles solution into Abelian and non-Abelian components. We found that the semi-infinite string singularity in the gauge potentials is a contribution from the Higgs field of the one-half monopole in both of the solutions. The non-Abelian components of the gauge potentials are able to remove the point singularity of the Abelian components of the 't Hooft-Polyakov monopole but not the string singularity of the one-half monopole which is topological in nature. Hence the total energy of a one monopole is infinite in the Maxwell electromagnetic theory but the total energy of a one-half monopole is finite. By analyzing the magnetic fields and the gauge covariant derivatives of the Higgs field, we are able to conclude that both the one-half integer monopoles solutions are indeed non-BPS even in the limit of vanishing Higgs self-coupling constant.
Critical integer quantum Hall topology in the integrable Maryland model
NASA Astrophysics Data System (ADS)
Ganeshan, Sriram; Kechedzhi, Kostyantyn
2014-03-01
One-dimensional tight binding models such as Aubry-Andre-Harper (AAH) model (with onsite cosine potential) and the integrable Maryland model (with onsite tangent potential) have been the subjects of extensive theoretical research in localization studies. AAH can be directly mapped onto the two-dimensional Hofstadter model that manifests the integer quantum Hall topology on a lattice. However, no such connection has been made for the Maryland model (MM). In this talk, we present a generalized model that contains AAH and MM as the limiting cases with the MM lying precisely at a topological quantum phase transition (TQPT) point. A remarkable feature of this critical point is that the 1D MM retains well-defined energy gaps whereas the equivalent 2D model becomes gapless, signifying the 2D nature of the TQPT. The criticality allows us to associate topological invariants with the Maryland model in a restricted mathematical sense at the special filling factors that are adiabatically connected to the spectral gaps in the 1D Aubry-Andre-Harper model. Our theory presented in this work establishes deep and unexpected mathematical connections between 2D topological models and a family of 1D incommensurate localization models. This work is supported by JQI-NSF-PFC, Microsoft Q and JQI-ARO-MU.
Preconditioning 2D Integer Data for Fast Convex Hull Computations.
Cadenas, José Oswaldo; Megson, Graham M; Luengo Hendriks, Cris L
2016-01-01
In order to accelerate computing the convex hull on a set of n points, a heuristic procedure is often applied to reduce the number of points to a set of s points, s ≤ n, which also contains the same hull. We present an algorithm to precondition 2D data with integer coordinates bounded by a box of size p × q before building a 2D convex hull, with three distinct advantages. First, we prove that under the condition min(p, q) ≤ n the algorithm executes in time within O(n); second, no explicit sorting of data is required; and third, the reduced set of s points forms a simple polygonal chain and thus can be directly pipelined into an O(n) time convex hull algorithm. This paper empirically evaluates and quantifies the speed up gained by preconditioning a set of points by a method based on the proposed algorithm before using common convex hull algorithms to build the final hull. A speedup factor of at least four is consistently found from experiments on various datasets when the condition min(p, q) ≤ n holds; the smaller the ratio min(p, q)/n is in the dataset, the greater the speedup factor achieved. PMID:26938221
Near integer tune for polarization preservation in the AGS
Tsoupas N.; Ahrens, L.; Bai, M.; Brown, K.; Glenn, J.W.; Huang, H.; MacKay, W.W.; Roser, T.; Schoefer, V.; Zeno, K.
2012-05-20
The high energy (T = 250 GeV) polarized proton beam experiments performed in RHIC, require high polarization of the beam. In order to preserve the polarization of the proton beam, during the acceleration in the AGS, which is the pre-injector to RHIC, we have installed in AGS two partial helical magnets which minimize the loss of the beam polarization caused by the various intrinsic spin resonances occurring during the proton acceleration. The minimization of the polarization loss during the acceleration cycle, requires that the vertical tune of the AGS is between the values of 8.97 and 8.985 during the acceleration. With the AGS constrained to run at near integer tune {approx}8.980, the perturbations to the beam caused by the partial helical magnets are large and also result in large beta and dispersion waves. To mitigate the adverse effect of the partial helices on the optics of the AGS, we have installed in specified straight sections of the AGS compensation quads and we have also generated a beam bump at the location of the cold partial helix. In this paper we present the beam optics of the AGS which ameliorates the adverse effect of the two partial helices on the beam optics.
Preconditioning 2D Integer Data for Fast Convex Hull Computations
2016-01-01
In order to accelerate computing the convex hull on a set of n points, a heuristic procedure is often applied to reduce the number of points to a set of s points, s ≤ n, which also contains the same hull. We present an algorithm to precondition 2D data with integer coordinates bounded by a box of size p × q before building a 2D convex hull, with three distinct advantages. First, we prove that under the condition min(p, q) ≤ n the algorithm executes in time within O(n); second, no explicit sorting of data is required; and third, the reduced set of s points forms a simple polygonal chain and thus can be directly pipelined into an O(n) time convex hull algorithm. This paper empirically evaluates and quantifies the speed up gained by preconditioning a set of points by a method based on the proposed algorithm before using common convex hull algorithms to build the final hull. A speedup factor of at least four is consistently found from experiments on various datasets when the condition min(p, q) ≤ n holds; the smaller the ratio min(p, q)/n is in the dataset, the greater the speedup factor achieved. PMID:26938221
Kinetics of nutrient and metal release from decomposing lake sediments
NASA Astrophysics Data System (ADS)
Matisoff, Gerald; Fisher, J. Berton; McCall, Peter L.
1981-12-01
Rates of anaerobic decomposition of Lake Erie sediments were determined for seven depth intervals at three temperatures. Sealed sediment sections were incubated under anoxic conditions and the interstitial waters were serially sampled over a period of approximately 200 days. Concentration increases of bicarbonate, phosphate, ammonium, Ca, Mg, Fe and Mn in pore water within any given depth interval followed zero order kinetics over the sampling period and exhibited Arrhenius temperature dependency. Rates of release to the pore waters were proportional to the concentrations in the solid phases, indicating first order kinetics overall. The rates and temperature dependencies of these fermentation reactions were only slightly less than those reported from sediments undergoing sulfate reduction. The observed release rates decreased exponentially with depth in the sediment due to a corresponding decrease in the amount of metabolizable organic matter and acid hydrolyzable mineral phases. A stoichiometric model was constructed utilizing the observed release rates and assumed chemical reactions to predict the stoichiometry of the decomposing organic matter and the nature of the hydrogen buffer. The modeling indicates that 60% of the observed bicarbonate release is the direct result of organic decomposition, that 20% of the release is from the dissolution of calcium carbonate mineral phases, and that the remaining 20% of the release is from the dissolution of magnesium, iron und manganese carbonate mineral phases. Kinetic modeling of the observed production rates accurately predicts the vertical profiles of Ca, Mg, Fe and Mn, but cannot quantitatively account for all the concentration differences of the nutrient elements C, N and P. This implies that in addition to decomposition, increased depositional flux also accounts for the significant changes in concentrations of the nutrient elements in the near surface sediments.
Biogeochemical implications of decomposing jellyfish blooms in a changing climate
NASA Astrophysics Data System (ADS)
Chelsky, Ariella; Pitt, Kylie A.; Welsh, David T.
2015-03-01
Jellyfish often exhibit 'boom and bust' population dynamics whereby they proliferate rapidly and then die en masse and decompose. The few studies that have investigated post-bloom processes have not studied how changing ocean conditions will alter rates of decomposition. Climate change will result in warmer and more acidic waters, and studies therefore need to consider these factors in concert to determine their combined effect on decomposition processes. To quantify the effect, we measured oxygen consumption and nutrient regeneration rates during decomposition of Catostylus mosaicus in mesocosms at current average summer pH and temperature (pH 8.0 and 27 °C) as well as conditions projected for year 2100 (pH 7.8 and 30 °C) and compared these fluxes to control mesocosms without jellyfish over 12 days. We hypothesised that rates of jellyfish decomposition, as measured by oxygen demand and nutrient regeneration, would be accelerated in the end-of-century treatments, compared to present day treatments. Overall decomposition rates were only slightly elevated under end-of-century conditions, and the difference was only significant for ammonium fluxes from 19 h until 43 h after the experiment commenced. The difference between treatments was much smaller than would be expected due to the temperature increase, based on theoretical modelling of jellyfish decomposition which predicts a Q10 of 4.28, or a 1.5 fold increase in decomposition rates. This highlights the importance of investigating net effects on decomposition rates, as simultaneous shifts in temperature and pH may not follow patterns predicted due to one stressor alone. Ultimately, these results suggest that rates of oxygen consumption and nutrient regeneration resulting from collapsed jellyfish blooms may not change drastically over the next 100 years.
Double-Resonance Facilitated Decomposion of Emission Spectra
NASA Astrophysics Data System (ADS)
Kato, Ryota; Ishikawa, Haruki
2016-06-01
Emission spectra provide us with rich information about the excited-state processes such as proton-transfer, charge-transfer and so on. In the cases that more than one excited states are involved, emission spectra from different excited states sometimes overlap and a decomposition of the overlapped spectra is desired. One of the methods to perform a decomposition is a time-resolved fluorescence technique. It uses a difference in time evolutions of components involved. However, in the gas-phase, a concentration of the sample is frequently too small to carry out this method. On the other hand, double-resonance technique is a very powerful tool to discriminate or identify a common species in the spectra in the gas-phase. Thus, in the present study, we applied the double-resonance technique to resolve the overlapped emission spectra. When transient IR absorption spectra of the excited state are available, we can label the population of the certain species by the IR excitation with a proper selection of the IR wavenumbers. Thus, we can obtain the emission spectra of labeled species by subtracting the emission spectra with IR labeling from that without IR. In the present study, we chose the charge-transfer emission spectra of cyanophenyldisilane (CPDS) as a test system. One of us reported that two charge-transfer (CT) states are involved in the intramolecular charge-transfer (ICT) process of CPDS-water cluster and recorded the transient IR spectra. As expected, we have succeeded in resolving the CT emission spectra of CPDS-water cluster by the double resonance facilitated decomposion technique. In the present paper, we will report the details of the experimental scheme and the results of the decomposition of the emission spectra. H. Ishikawa, et al., Chem. Phys. Phys. Chem., 9, 117 (2007).
Decomposer diversity and identity influence plant diversity effects on ecosystem functioning.
Eisenhauer, Nico; Reich, Peter B; Isbell, Forest
2012-10-01
Plant productivity and other ecosystem functions often increase with plant diversity at a local scale. Alongside various plant-centered explanations for this pattern, there is accumulating evidence that multi-trophic interactions shape this relationship. Here, we investigated for the first time if plant diversity effects on ecosystem functioning are mediated or driven by decomposer animal diversity and identity using a double-diversity microcosm experiment. We show that many ecosystem processes and ecosystem multifunctionality (herbaceous shoot biomass production, litter removal, and N uptake) were affected by both plant and decomposer diversity, with ecosystem process rates often being maximal at intermediate to high plant and decomposer diversity and minimal at both low plant and decomposer diversity. Decomposers relaxed interspecific plant competition by enlarging chemical (increased N uptake and surface-litter decomposition) and spatial (increasing deep-root biomass) habitat space and by promoting plant complementarity. Anecic earthworms and isopods functioned as key decomposers; although decomposer diversity effects did not solely rely on these two decomposer species, positive plant net biodiversity and complementarity effects only occurred in the absence of isopods and the presence of anecic earthworms. Using a structural equation model, we explained 76% of the variance in plant complementarity, identified direct and indirect effect paths, and showed that the presence of key decomposers accounted for approximately three-quarters of the explained variance. We conclude that decomposer animals have been underappreciated as contributing agents of plant diversity-ecosystem functioning relationships. Elevated decomposer performance at high plant diversity found in previous experiments likely positively feeds back to plant performance, thus contributing to the positive relationship between plant diversity and ecosystem functioning.
Finite-Dimensional Half-Integer Weight Modules over Queer Lie Superalgebras
NASA Astrophysics Data System (ADS)
Cheng, Shun-Jen; Kwon, Jae-Hoon
2016-09-01
We give a new interpretation of representation theory of the finite-dimensional half-integer weight modules over the queer Lie superalgebra {{q}(n)}. It is given in terms of the Brundan's work on finite-dimensional integer weight {{q}(n)}-modules by means of Lusztig's canonical basis. Using this viewpoint we compute the characters of the finite-dimensional half-integer weight irreducible modules. For a large class of irreducible modules whose highest weights are of special types (i.e., totally connected or totally disconnected) we derive closed-form character formulas that are reminiscent of the Kac-Wakimoto character formula for basic Lie superalgebras.
Pan, Xu; Cornelissen, Johannes H C; Zhao, Wei-Wei; Liu, Guo-Fang; Hu, Yu-Kun; Prinzing, Andreas; Dong, Ming; Cornwell, William K
2014-09-01
Leaf litter decomposability is an important effect trait for ecosystem functioning. However, it is unknown how this effect trait evolved through plant history as a leaf 'afterlife' integrator of the evolution of multiple underlying traits upon which adaptive selection must have acted. Did decomposability evolve in a Brownian fashion without any constraints? Was evolution rapid at first and then slowed? Or was there an underlying mean-reverting process that makes the evolution of extreme trait values unlikely? Here, we test the hypothesis that the evolution of decomposability has undergone certain mean-reverting forces due to strong constraints and trade-offs in the leaf traits that have afterlife effects on litter quality to decomposers. In order to test this, we examined the leaf litter decomposability and seven key leaf traits of 48 tree species in the temperate area of China and fitted them to three evolutionary models: Brownian motion model (BM), Early burst model (EB), and Ornstein-Uhlenbeck model (OU). The OU model, which does not allow unlimited trait divergence through time, was the best fit model for leaf litter decomposability and all seven leaf traits. These results support the hypothesis that neither decomposability nor the underlying traits has been able to diverge toward progressively extreme values through evolutionary time. These results have reinforced our understanding of the relationships between leaf litter decomposability and leaf traits in an evolutionary perspective and may be a helpful step toward reconstructing deep-time carbon cycling based on taxonomic composition with more confidence. PMID:25535551
Pan, Xu; Cornelissen, Johannes H C; Zhao, Wei-Wei; Liu, Guo-Fang; Hu, Yu-Kun; Prinzing, Andreas; Dong, Ming; Cornwell, William K
2014-09-01
Leaf litter decomposability is an important effect trait for ecosystem functioning. However, it is unknown how this effect trait evolved through plant history as a leaf 'afterlife' integrator of the evolution of multiple underlying traits upon which adaptive selection must have acted. Did decomposability evolve in a Brownian fashion without any constraints? Was evolution rapid at first and then slowed? Or was there an underlying mean-reverting process that makes the evolution of extreme trait values unlikely? Here, we test the hypothesis that the evolution of decomposability has undergone certain mean-reverting forces due to strong constraints and trade-offs in the leaf traits that have afterlife effects on litter quality to decomposers. In order to test this, we examined the leaf litter decomposability and seven key leaf traits of 48 tree species in the temperate area of China and fitted them to three evolutionary models: Brownian motion model (BM), Early burst model (EB), and Ornstein-Uhlenbeck model (OU). The OU model, which does not allow unlimited trait divergence through time, was the best fit model for leaf litter decomposability and all seven leaf traits. These results support the hypothesis that neither decomposability nor the underlying traits has been able to diverge toward progressively extreme values through evolutionary time. These results have reinforced our understanding of the relationships between leaf litter decomposability and leaf traits in an evolutionary perspective and may be a helpful step toward reconstructing deep-time carbon cycling based on taxonomic composition with more confidence.
Emergence of integer quantum Hall effect from chaos
NASA Astrophysics Data System (ADS)
Tian, Chushun; Chen, Yu; Wang, Jiao
2016-02-01
We present an analytic microscopic theory showing that in a large class of spin-1/2 quasiperiodic quantum kicked rotors, a dynamical analog of the integer quantum Hall effect (IQHE) emerges from an intrinsic chaotic structure. Specifically, the inverse of the Planck's quantum (he) and the rotor's energy growth rate mimic the "filling fraction" and the "longitudinal conductivity" in conventional IQHE, respectively, and a hidden quantum number is found to mimic the "quantized Hall conductivity." We show that for an infinite discrete set of critical values of he, the long-time energy growth rate is universal and of order of unity ("metallic" phase), but otherwise vanishes ("insulating" phase). Moreover, the rotor insulating phases are topological, each of which is characterized by a hidden quantum number. This number exhibits universal behavior for small he, i.e., it jumps by unity whenever he decreases, passing through each critical value. This intriguing phenomenon is not triggered by the likes of Landau band filling, well known to be the mechanism for conventional IQHE, and far beyond the canonical Thouless-Kohmoto-Nightingale-Nijs paradigm for quantum Hall transitions. Instead, this dynamical phenomenon is of strong chaos origin; it does not occur when the dynamics is (partially) regular. More precisely, we find that a topological object, similar to the topological theta angle in quantum chromodynamics, emerges from strongly chaotic motion at microscopic scales, and its renormalization gives the hidden quantum number. Our analytic results are confirmed by numerical simulations. Our findings indicate that rich topological quantum phenomena can emerge from chaos and might point to a new direction of study in the interdisciplinary area straddling chaotic dynamics and condensed matter physics. This work is a substantial extension of a short paper published earlier by two of us [Y. Chen and C. Tian, Phys. Rev. Lett. 113, 216802 (2014), 10.1103/PhysRevLett.113.216802].
On the smallest value of the maximal modulus of an algebraic integer
NASA Astrophysics Data System (ADS)
Rhin, Georges; Wu, Qiang
2007-06-01
The house of an algebraic integer of degree d is the largest modulus of its conjugates. For dleq 28 , we compute the smallest house >1 of degree d , say m (d) . As a consequence we improve Matveev's theorem on the lower bound of m (d). We show that, in this range, the conjecture of Schinzel-Zassenhaus is satisfied. The minimal polynomial of any algebraic integer boldsymbol alpha whose house is equal to m (d) is a factor of a bi-, tri- or quadrinomial. The computations use a family of explicit auxiliary functions. These functions depend on generalizations of the integer transfinite diameter of some compact sets in mathbb{C}. They give better bounds than the classical ones for the coefficients of the minimal polynomial of an algebraic integer boldsymbol alpha whose house is small.
NASA Astrophysics Data System (ADS)
Jiang, Zhuo; Xie, Chengjun
2013-12-01
This paper improved the algorithm of reversible integer linear transform on finite interval [0,255], which can realize reversible integer linear transform in whole number axis shielding data LSB (least significant bit). Firstly, this method use integer wavelet transformation based on lifting scheme to transform the original image, and select the transformed high frequency areas as information hiding area, meanwhile transform the high frequency coefficients blocks in integer linear way and embed the secret information in LSB of each coefficient, then information hiding by embedding the opposite steps. To extract data bits and recover the host image, a similar reverse procedure can be conducted, and the original host image can be lossless recovered. The simulation experimental results show that this method has good secrecy and concealment, after conducted the CDF (m, n) and DD (m, n) series of wavelet transformed. This method can be applied to information security domain, such as medicine, law and military.
Time domain simulation of Li-ion batteries using non-integer order equivalent electrical circuit
NASA Astrophysics Data System (ADS)
Riu, D.; Montaru, M.; Bultel, Y.
2013-06-01
For electric vehicle (EV) or hybrid EV (HEV) development and integration of renewables in electrical networks, battery monitoring systems have to be more and more precise to take into account the state-of-charge and the dynamic behavior of the battery. Some non-integer order models of electrochemical batteries have been proposed in literacy with a good accuracy and a low number of parameters in the frequential domain. Nevertheless, time simulation of such models required to approximate this non-integer order system by an equivalent high integer order model. An adapted algorithm is then proposed in this article to simulate the non-integer order model without any approximation, thanks to the construction of a 3-order generalized state-space system. This algorithm is applied and validated on a 2.3 A.h Li-ion battery.
Schädler, Martin
2010-01-01
The intensive discussion on the importance of biodiversity for the stability of essential processes in ecosystems has prompted a multitude of studies since the middle of the last century. Nevertheless, research has been extremely biased by focusing on the producer level, while studies on the impacts of decomposer diversity on the stability of ecosystem functions are lacking. Here, we investigate the impacts of decomposer diversity on the stability (reliability) of three important aboveground and belowground ecosystem functions: primary productivity (shoot and root biomass), litter decomposition, and herbivore infestation. For this, we analyzed the results of three laboratory experiments manipulating decomposer diversity (1–3 species) in comparison to decomposer-free treatments in terms of variability of the measured variables. Decomposer diversity often significantly but inconsistently affected the stability of all aboveground and belowground ecosystem functions investigated in the present study. While primary productivity was mainly destabilized, litter decomposition and aphid infestation were essentially stabilized by increasing decomposer diversity. However, impacts of decomposer diversity varied between plant community and fertility treatments. There was no general effect of the presence of decomposers on stability and no trend toward weaker effects in fertilized communities and legume communities. This indicates that impacts of decomposers are based on more than effects on nutrient availability. Although inconsistent impacts complicate the estimation of consequences of belowground diversity loss, underpinning mechanisms of the observed patterns are discussed. Impacts of decomposer diversity on the stability of essential ecosystem functions differed between plant communities of varying composition and fertility, implicating that human-induced changes of biodiversity and land-use management might have unpredictable effects on the processes mankind relies on
Particle in a Moebius wire and half-integer orbital angular momentum
Miliordos, Evangelos
2011-06-15
Restricting one particle on the rim of a Moebius strip (Moebius wire), its wave functions are explicitly calculated through the nonrelativistic quantum theory. Demanding the wave function to be single valued, it is proven that in the case of a narrow strip the orbital angular momentum of the particle takes both integer and half-integer values of ({h_bar}/2{pi}). In addition, the energy values of two chiral Moebius wires are proven to be equal.
Ma, Yue; Wang, Guo-xiang; Cao, Xun; Wang, Xiao-yun; Ma, Jie
2015-07-01
In order to study the coupling effects of decomposed Potamogeton crispus (P. crispus) and growing Ceratophyllum demersum (C. demersum) on water quality and the effects of different decomposed biomass on plant growth, the simulating experiments for seasonal changes of submerged macrophytes were conducted. The results indicated that the nutrient concentrations in water remained at a relatively low level with different decomposed biomass and they remained stable after 29 days of the experiment. The concentrations of total dissolved nitrogen (DTN), total nitrogen (TN), total phosphorous (TP), total dissolved phosphorous (DTP), organic carbon (TOC) and chlorophyll-a (Chl-a) were lower than 0. 514, 0. 559, 0. 080, 0. 014, 13. 94 and 26. 546 mg . L-1, respectively. The obvious improving effects on water quality were observed under coupling condition of decomposition and growth, especially when the treatment of decomposed P. crispus was 20 g, and the removal efficiency of TN, DTN, TP, DTP, TOC and Chl-a reached 89. 67% , 52. 51%, 94. 99%, 55. 59% and 98. 55%, respectively. Compared with the physiology of C. demersum in the early stage, the contents of total chlorophyll, soluble protein and malondialdehyde all increased under different decomposed biomass conditions, which suggested that the nutrient released from decomposed P. crispus promoted the growth of C. demersum. The coupling effects between P. crispus decomposition and C. demersum growth showed better improving effect on water quality and growth of C. demersum with treatment of 20 g decomposed P. crispus.
Effects of decomposing rice straw on growth of and nitrogen fixation by Rhizobium
Rice, E.L.; Huang, C.Y.; Lin, C.Y.
1981-03-01
Five phenolic compounds produced in decomposing rice straw and sterile extracts of decomposing rice straw in soil were very inhibitory to growth of three strains of Rhizobium. The effects were additive and in several instances synergistic. The phenolic compounds also reduced nodule numbers and hemoglobin content of the nodules in two bean (Phaseohus vulgaris) varieties. Extracts of decomposing rice straw in soil (same concentration as in the soil) significantly reduced N/sub 2/ fixation (acetylene reduction) in Bush Black Seeded beans. This may explain in part the great reduction in soybean yields in Taiwan following rice crops when the rice stubble is left in the field.
A 250 mV Cu/SiO2/W Memristor with Half-Integer Quantum Conductance States.
Nandakumar, S R; Minvielle, Marie; Nagar, Saurabh; Dubourdieu, Catherine; Rajendran, Bipin
2016-03-01
Memristive devices, whose conductance depends on previous programming history, are of significant interest for building nonvolatile memory and brain-inspired computing systems. Here, we report half-integer quantized conductance transitions G = (n/2) (2e(2)/h) for n = 1, 2, 3, etc., in Cu/SiO2/W memristive devices observed below 300 mV at room temperature. This is attributed to the nanoscale filamentary nature of Cu conductance pathways formed inside SiO2. Retention measurements also show spontaneous filament decay with quantized conductance levels. Numerical simulations shed light into the dynamics underlying the data retention loss mechanisms and provide new insights into the nanoscale physics of memristive devices and trade-offs involved in engineering them for computational applications.
Pan, Xu; Cornelissen, Johannes H C; Zhao, Wei-Wei; Liu, Guo-Fang; Hu, Yu-Kun; Prinzing, Andreas; Dong, Ming; Cornwell, William K
2014-01-01
Leaf litter decomposability is an important effect trait for ecosystem functioning. However, it is unknown how this effect trait evolved through plant history as a leaf ‘afterlife’ integrator of the evolution of multiple underlying traits upon which adaptive selection must have acted. Did decomposability evolve in a Brownian fashion without any constraints? Was evolution rapid at first and then slowed? Or was there an underlying mean-reverting process that makes the evolution of extreme trait values unlikely? Here, we test the hypothesis that the evolution of decomposability has undergone certain mean-reverting forces due to strong constraints and trade-offs in the leaf traits that have afterlife effects on litter quality to decomposers. In order to test this, we examined the leaf litter decomposability and seven key leaf traits of 48 tree species in the temperate area of China and fitted them to three evolutionary models: Brownian motion model (BM), Early burst model (EB), and Ornstein-Uhlenbeck model (OU). The OU model, which does not allow unlimited trait divergence through time, was the best fit model for leaf litter decomposability and all seven leaf traits. These results support the hypothesis that neither decomposability nor the underlying traits has been able to diverge toward progressively extreme values through evolutionary time. These results have reinforced our understanding of the relationships between leaf litter decomposability and leaf traits in an evolutionary perspective and may be a helpful step toward reconstructing deep-time carbon cycling based on taxonomic composition with more confidence. PMID:25535551
Using Integer Clocks to Verify the Timing-Sync Sensor Network Protocol
NASA Technical Reports Server (NTRS)
Huang, Xiaowan; Singh, Anu; Smolka, Scott A.
2010-01-01
We use the UPPAAL model checker for Timed Automata to verify the Timing-Sync time-synchronization protocol for sensor networks (TPSN). The TPSN protocol seeks to provide network-wide synchronization of the distributed clocks in a sensor network. Clock-synchronization algorithms for sensor networks such as TPSN must be able to perform arithmetic on clock values to calculate clock drift and network propagation delays. They must be able to read the value of a local clock and assign it to another local clock. Such operations are not directly supported by the theory of Timed Automata. To overcome this formal-modeling obstacle, we augment the UPPAAL specification language with the integer clock derived type. Integer clocks, which are essentially integer variables that are periodically incremented by a global pulse generator, greatly facilitate the encoding of the operations required to synchronize clocks as in the TPSN protocol. With this integer-clock-based model of TPSN in hand, we use UPPAAL to verify that the protocol achieves network-wide time synchronization and is devoid of deadlock. We also use the UPPAAL Tracer tool to illustrate how integer clocks can be used to capture clock drift and resynchronization during protocol execution
NASA Technical Reports Server (NTRS)
Shyu, H. C.; Reed, I. S.; Truong, T. K.; Hsu, I. S.; Chang, J. J.
1987-01-01
A quadratic-polynomial Fermat residue number system (QFNS) has been used to compute complex integer multiplications. The advantage of such a QFNS is that a complex integer multiplication requires only two integer multiplications. In this article, a new type Fermat number multiplier is developed which eliminates the initialization condition of the previous method. It is shown that the new complex multiplier can be implemented on a single VLSI chip. Such a chip is designed and fabricated in CMOS-Pw technology.
NASA Technical Reports Server (NTRS)
Ferencz, Donald C.; Viterna, Larry A.
1991-01-01
ALPS is a computer program which can be used to solve general linear program (optimization) problems. ALPS was designed for those who have minimal linear programming (LP) knowledge and features a menu-driven scheme to guide the user through the process of creating and solving LP formulations. Once created, the problems can be edited and stored in standard DOS ASCII files to provide portability to various word processors or even other linear programming packages. Unlike many math-oriented LP solvers, ALPS contains an LP parser that reads through the LP formulation and reports several types of errors to the user. ALPS provides a large amount of solution data which is often useful in problem solving. In addition to pure linear programs, ALPS can solve for integer, mixed integer, and binary type problems. Pure linear programs are solved with the revised simplex method. Integer or mixed integer programs are solved initially with the revised simplex, and the completed using the branch-and-bound technique. Binary programs are solved with the method of implicit enumeration. This manual describes how to use ALPS to create, edit, and solve linear programming problems. Instructions for installing ALPS on a PC compatible computer are included in the appendices along with a general introduction to linear programming. A programmers guide is also included for assistance in modifying and maintaining the program.
Cornthwaite, H M; Watterson, J H
2014-10-01
The influence of body position and microclimate on ketamine (KET) and metabolite distribution in decomposed bone tissue was examined. Rats received 75 mg/kg (i.p.) KET (n = 30) or remained drug-free (controls, n = 4). Following euthanasia, rats were divided into two groups and placed outdoors to decompose in one of the three positions: supine (SUP), prone (PRO) or upright (UPR). One group decomposed in a shaded, wooded microclimate (Site 1) while the other decomposed in an exposed sunlit microclimate with gravel substrate (Site 2), roughly 500 m from Site 1. Following decomposition, bones (lumbar vertebrae, thoracic vertebra, cervical vertebrae, rib, pelvis, femora, tibiae, humeri and scapulae) were collected and sorted for analysis. Clean, ground bones underwent microwave-assisted extraction using acetone : hexane mixture (1 : 1, v/v), followed by solid-phase extraction and analysis using GC-MS. Drug levels, expressed as mass normalized response ratios, were compared across all bone types between body position and microclimates. Bone type was a main effect (P < 0.05) for drug level and drug/metabolite level ratio for all body positions and microclimates examined. Microclimate and body position significantly influenced observed drug levels: higher levels were observed in carcasses decomposing in direct sunlight, where reduced entomological activity led to slowed decomposition.
NASA Astrophysics Data System (ADS)
Katayama, Ayumi; Khoon Koh, Lip; Kume, Tomonori; Makita, Naoki; Matsumoto, Kazuho; Ohashi, Mizue
2016-04-01
Considerable carbon is allocated belowground and used for respiration and production of roots. It is reported that approximately 40 % of GPP is allocated belowground in a Bornean tropical rainforest, which is much higher than those in Neotropical rainforests. This may be caused by high root production in this forest. Ingrowth core is a popular method for estimating fine root production, but recent study by Osawa et al. (2012) showed potential underestimates of this method because of the lack of consideration of the impact of decomposed roots. It is important to estimate fine root production with consideration for the decomposed roots, especially in tropics where decomposition rate is higher than other regions. Therefore, objective of this study is to estimate fine root production with consideration of decomposed roots using ingrowth cores and root litter-bag in the tropical rainforest. The study was conducted in Lambir Hills National Park in Borneo. Ingrowth cores and litter bags for fine roots were buried in March 2013. Eighteen ingrowth cores and 27 litter bags were collected in May, September 2013, March 2014 and March 2015, respectively. Fine root production was comparable to aboveground biomass increment and litterfall amount, and accounted only 10% of GPP in this study site, suggesting most of the carbon allocated to belowground might be used for other purposes. Fine root production was comparable to those in Neotropics. Decomposed roots accounted for 18% of fine root production. This result suggests that no consideration of decomposed fine roots may cause underestimate of fine root production.
Motz, Benjamin A.; Erickson, Molly A.; Hetrick, William P.
2013-01-01
Humans perceive a wide range of temporal patterns, including those rhythms that occur in music, speech, and movement; however, there are constraints on the rhythmic patterns that we can represent. Past research has shown that sequences in which sounds occur regularly at non-metrical locations in a repeating beat period (non-integer ratio subdivisions of the beat, e.g. sounds at 430 ms in a 1000 ms beat) are represented less accurately than sequences with metrical relationships, where events occur at even subdivisions of the beat (integer ratios, e.g. sounds at 500 ms in a 1000 ms beat). Why do non-integer ratio rhythms present cognitive challenges? An emerging theory is that non-integer ratio sequences are represented incorrectly, “regularized” in the direction of the nearest metrical pattern, and the present study sought evidence of such perceptual regularization toward integer ratio relationships. Participants listened to metrical and non-metrical rhythmic auditory sequences during electroencephalogram recording, and sounds were pseudorandomly omitted from the stimulus sequence. Cortical responses to these omissions (omission elicited potentials; OEPs) were used to estimate the timing of expectations for omitted sounds in integer ratio and non-integer ratio locations. OEP amplitude and onset latency measures indicated that expectations for non-integer ratio sequences are distorted toward the nearest metrical location in the rhythmic period. These top-down effects demonstrate metrical regularization in a purely perceptual context, and provide support for dynamical accounts of rhythm perception. PMID:23434916
Physical Applications of a Simple Approximation of Bessel Functions of Integer Order
ERIC Educational Resources Information Center
Barsan, V.; Cojocaru, S.
2007-01-01
Applications of a simple approximation of Bessel functions of integer order, in terms of trigonometric functions, are discussed for several examples from electromagnetism and optics. The method may be applied in the intermediate regime, bridging the "small values regime" and the "asymptotic" one, and covering, in this way, an area of great…
REVERSIBLE N-BIT TO N-BIT INTEGER HAAR-LIKE TRANSFORMS
Duchaineau, M; Joy, K I; Senecal, J
2004-02-14
We introduce TLHaar, an n-bit to n-bit reversible transform similar to the Haar IntegerWavelet Transform (IWT). TLHaar uses lookup tables that approximate the Haar IWT, but reorder the coefficients so they fit into n bits. TLHaar is suited for lossless compression in fixed-width channels, such as digital video channels and graphics hardware frame buffers.
NASA Astrophysics Data System (ADS)
Pospelov, A. I.
2016-08-01
Adaptive methods for the polyhedral approximation of the convex Edgeworth-Pareto hull in multiobjective monotone integer optimization problems are proposed and studied. For these methods, theoretical convergence rate estimates with respect to the number of vertices are obtained. The estimates coincide in order with those for filling and augmentation H-methods intended for the approximation of nonsmooth convex compact bodies.
NASA Astrophysics Data System (ADS)
Li, J. C.; Gong, B.; Wang, H. G.
2016-08-01
Optimal development of shale gas fields involves designing a most productive fracturing network for hydraulic stimulation processes and operating wells appropriately throughout the production time. A hydraulic fracturing network design-determining well placement, number of fracturing stages, and fracture lengths-is defined by specifying a set of integer ordered blocks to drill wells and create fractures in a discrete shale gas reservoir model. The well control variables such as bottom hole pressures or production rates for well operations are real valued. Shale gas development problems, therefore, can be mathematically formulated with mixed-integer optimization models. A shale gas reservoir simulator is used to evaluate the production performance for a hydraulic fracturing and well control plan. To find the optimal fracturing design and well operation is challenging because the problem is a mixed integer optimization problem and entails computationally expensive reservoir simulation. A dynamic simplex interpolation-based alternate subspace (DSIAS) search method is applied for mixed integer optimization problems associated with shale gas development projects. The optimization performance is demonstrated with the example case of the development of the Barnett Shale field. The optimization results of DSIAS are compared with those of a pattern search algorithm.
Richards, Cameron S; Rowlinson, Catherine C; Cuttiford, Lue; Grimsley, Rebecca; Hall, Martin J R
2013-01-01
The development rate of immature Calliphora vicina reared on decomposed liver was significantly slower, by as much as 30 h (55.4 % of total development time) for mid-sized larvae, and 71 h (35.0 %) and 58 h (14.6 %) if using times to the onset of pupariation and eclosion, respectively, than those of immatures that developed on fresh whole pig's liver. Development rates of larvae reared on decomposed liver were also slower than those of larvae reared on minced pig's liver and frozen/thawed pig's liver. These results suggest that any estimate of minimum post-mortem interval may result in an over estimate if the blowflies used were developing on an already decomposed body.
Microbial activity and phosphorus uptake on decomposing leaf detritus in a heterotrophic stream
Elwood, J.W.; Mulholland, P.J.; Newbold, J.D.
1987-01-01
This paper reports results of experiments to determine the influence of microbes associated with decomposing leaf detritus on the uptake length and retention of phosphorus in a heterotrophic stream. The purposes were to (1) determine the relationship between the biomass and activity of microbes associated with decomposing leaf detritus and the uptake length of PO/sub 4/-P in a stream; (2) compare the temporal pattern in the uptake rate of phosphorus among species of leaves that have been shown to differ in their rate of decomposition as a function of time in a stream; and (3) examine the temporal patterns in the net accumulation, leaching, and transformations of phosphorus in flow-through systems containing decomposing leaf detritus.
Stefanutti, Luca; Robusto, Egidio; Vianello, Michelangelo; Anselmi, Pasquale
2013-06-01
A formal model is proposed that decomposes the implicit association test (IAT) effect into three process components: stimuli discrimination, automatic association, and termination criterion. Both response accuracy and reaction time are considered. Four independent and parallel Poisson processes, one for each of the four label categories of the IAT, are assumed. The model parameters are the rate at which information accrues on the counter of each process and the amount of information that is needed before a response is given. The aim of this study is to present the model and an illustrative application in which the process components of a Coca-Pepsi IAT are decomposed.
Stefanutti, Luca; Robusto, Egidio; Vianello, Michelangelo; Anselmi, Pasquale
2013-06-01
A formal model is proposed that decomposes the implicit association test (IAT) effect into three process components: stimuli discrimination, automatic association, and termination criterion. Both response accuracy and reaction time are considered. Four independent and parallel Poisson processes, one for each of the four label categories of the IAT, are assumed. The model parameters are the rate at which information accrues on the counter of each process and the amount of information that is needed before a response is given. The aim of this study is to present the model and an illustrative application in which the process components of a Coca-Pepsi IAT are decomposed. PMID:23239064
ERIC Educational Resources Information Center
Shiue, Ya-Ming
2007-01-01
Based on the decomposed theory of planned behavior, this study used path analysis to examine the relative strength of the factors that influence teachers' use of instructional technology. The study focused on teachers' use of word processors, spreadsheets, presentation software, e-mail, and Web browsers. A path analysis was performed on…
Kill the Song--Steal the Show: What Does Distinguish Predicative Metaphors from Decomposable Idioms?
ERIC Educational Resources Information Center
Caillies, Stephanie; Declercq, Christelle
2011-01-01
This study examined the semantic processing difference between decomposable idioms and novel predicative metaphors. It was hypothesized that idiom comprehension results from the retrieval of a figurative meaning stored in memory, that metaphor comprehension requires a sense creation process and that this process difference affects the processing…
NASA Astrophysics Data System (ADS)
Wang, Chao; Yu, Rencheng; Zhou, Mingjiang
2011-05-01
From 2007 to 2009, large-scale blooms of green algae (the so-called "green tides") occurred every summer in the Yellow Sea, China. In June 2008, huge amounts of floating green algae accumulated along the coast of Qingdao and led to mass mortality of cultured abalone and sea cucumber. However, the mechanism for the mass mortality of cultured animals remains undetermined. This study examined the toxic effects of Ulva ( Enteromorpha) prolifera, the causative species of green tides in the Yellow Sea during the last three years. The acute toxicity of fresh culture medium and decomposing algal effluent of U. prolifera to the cultured abalone Haliotis discus hannai were tested. It was found that both fresh culture medium and decomposing algal effluent had toxic effects to abalone, and decomposing algal effluent was more toxic than fresh culture medium. The acute toxicity of decomposing algal effluent could be attributed to the ammonia and sulfide presented in the effluent, as well as the hypoxia caused by the decomposition process.
Gaze Fluctuations Are Not Additively Decomposable: Reply to Bogartz and Staub
ERIC Educational Resources Information Center
Kelty-Stephen, Damian G.; Mirman, Daniel
2013-01-01
Our previous work interpreted single-lognormal fits to inter-gaze distance (i.e., "gaze steps") histograms as evidence of multiplicativity and hence interactions across scales in visual cognition. Bogartz and Staub (2012) proposed that gaze steps are additively decomposable into fixations and saccades, matching the histograms better and…
Large-Scale Multiobjective Static Test Generation for Web-Based Testing with Integer Programming
ERIC Educational Resources Information Center
Nguyen, M. L.; Hui, Siu Cheung; Fong, A. C. M.
2013-01-01
Web-based testing has become a ubiquitous self-assessment method for online learning. One useful feature that is missing from today's web-based testing systems is the reliable capability to fulfill different assessment requirements of students based on a large-scale question data set. A promising approach for supporting large-scale web-based…
A Constraint Integer Programming Approach for Resource-Constrained Project Scheduling
NASA Astrophysics Data System (ADS)
Berthold, Timo; Heinz, Stefan; Lübbecke, Marco E.; Möhring, Rolf H.; Schulz, Jens
We propose a hybrid approach for solving the resource-constrained project scheduling problem which is an extremely hard to solve combinatorial optimization problem of practical relevance. Jobs have to be scheduled on (renewable) resources subject to precedence constraints such that the resource capacities are never exceeded and the latest completion time of all jobs is minimized.
ERIC Educational Resources Information Center
Lam, Tit-Loong; Foong, Yoke-Yeen
This simulation study involved the design of two two-stage tests in which the routing tests and the second-stage measurement testlets took the form of a multidimensional knapsack problem with prespecified target informations and constraints to be enumerated using the algorithm of E. Balas. Two conventional tests of similar length to the two-stage…
ERIC Educational Resources Information Center
Seth, Anupam
2009-01-01
Production planning and scheduling for printed circuit, board assembly has so far defied standard operations research approaches due to the size and complexity of the underlying problems, resulting in unexploited automation flexibility. In this thesis, the increasingly popular collect-and-place machine configuration is studied and the assembly…
NASA Astrophysics Data System (ADS)
Wu, C. Z.; Huang, G. H.; Yan, X. P.; Cai, Y. P.; Li, Y. P.
2010-05-01
Large crowds are increasingly common at political, social, economic, cultural and sports events in urban areas. This has led to attention on the management of evacuations under such situations. In this study, we optimise an approximation method for vehicle allocation and route planning in case of an evacuation. This method, based on an interval-parameter multi-objective optimisation model, has potential for use in a flexible decision support system for evacuation management. The modeling solutions are obtained by sequentially solving two sub-models corresponding to lower- and upper-bounds for the desired objective function value. The interval solutions are feasible and stable in the given decision space, and this may reduce the negative effects of uncertainty, thereby improving decision makers' estimates under different conditions. The resulting model can be used for a systematic analysis of the complex relationships among evacuation time, cost and environmental considerations. The results of a case study used to validate the proposed model show that the model does generate useful solutions for planning evacuation management and practices. Furthermore, these results are useful for evacuation planners, not only in making vehicle allocation decisions but also for providing insight into the tradeoffs among evacuation time, environmental considerations and economic objectives.
Selection of a minimum-boundary reserve network using integer programming.
Onal, Hayri; Briers, Robert A
2003-01-01
In the conservation literature, heuristic procedures have been employed to incorporate spatial considerations in reserve network selection with the presumption that computationally convenient optimization models would be too difficult or impossible to formulate. This paper extends the standard set-covering formulation to incorporate a particular spatial selection criterion, namely reducing the reserve boundary to the extent possible, when selecting a reserve network that represents a set of target species at least once. Applying the model to a dataset on the occurrence of breeding birds in Berkshire, UK, demonstrated that the technique resulted in significant reductions in reserve boundary length relative to solutions produced by the standard set-covering formulation. Computational results showed that moderately large reserve network selection problems could be solved without issue. Alternative solutions may be produced to explore trade-offs between boundary length, number of sites required or alternative criteria. PMID:12965014
Active strut placement using integer programming for the CSI Revolutionary Model
NASA Astrophysics Data System (ADS)
Padula, Sharon L.; Sandridge, Chris A.
1992-09-01
A method for determining the most effective locations for active struts on large space structures is developed and tested on the NASA CSI Evolutionary Model. Depending on the choice of weighting factors, the method can be used to maximize the maximum modal damping ratio or decay rate, or to maximize a mission-oriented measure of performance. Placement of 8, 16, and 32 active struts out of 1507 candidate truss elements is demonstrated. Preliminary estimates of damping enhancement are reported pending refined structural models and dynamic test results. The method can handle complicated FEM models wih a large number of truss elements and many target modes. It can treat each mode equally or it can emphasize the importance of selected modes. The method can eliminate some combinations of actuator locations based on topological constraints.
Topological Phase and Half-Integer Orbital Angular Momenta in Circular Quantum Dots
NASA Astrophysics Data System (ADS)
Kuleshov, V. M.; Mur, V. D.; Narozhny, N. B.; Lozovik, Yu. E.
2016-06-01
We show that there exists a non-trivial topological phase in circular two-dimensional quantum dots with an odd number of electrons. The possible non-zero value of this phase is explained by axial symmetry of two-dimensional quantum systems. The particular value of this phase (π ) is fixed by T-invariance and the Pauli exclusion principle and leads to half-integer values of the angular orbital momentum for ground states of such systems. This conclusion agrees with the experimental data for ground-state energies of few-electron circular quantum dots in perpendicular magnetic field (Schmidt et al. in Phys Rev B 51:5570, 1995). Hence, these data may be considered as the first experimental evidence for the existence of topological phase leading to half-integer quantization of the orbital angular momentum in circular quantum dots with an odd number of electrons.
NASA Astrophysics Data System (ADS)
Langel, Steven E.; Khanafseh, Samer M.; Pervan, Boris
2016-06-01
Differential carrier phase applications that utilize cycle resolution need the probability density function of the baseline estimate to quantify its region of concentration. For the integer bootstrap estimator, the density function has an analytical definition that enables probability calculations given perfect statistical knowledge of measurement and process noise. This paper derives a method to upper bound the tail probability of the integer bootstrapped GNSS baseline when the measurement and process noise correlation functions are unknown, but can be upper and lower bounded. The tail probability is shown to be a non-convex function of a vector of conditional variances, whose feasible region is a convex polytope. We show how to solve the non-convex optimization problem globally by discretizing the polytope into small hyper-rectangular elements, and demonstrate the method for a static baseline estimation problem.
An Integer-Coded Chaotic Particle Swarm Optimization for Traveling Salesman Problem
NASA Astrophysics Data System (ADS)
Yue, Chen; Yan-Duo, Zhang; Jing, Lu; Hui, Tian
Traveling Salesman Problem (TSP) is one of NP-hard combinatorial optimization problems, which will experience “combination explosion” when the problem goes beyond a certain size. Therefore, it has been a hot topic to search an effective solving method. The general mathematical model of TSP is discussed, and its permutation and combination based model is presented. Based on these, Integer-coded Chaotic Particle Swarm Optimization for solving TSP is proposed. Where, particle is encoded with integer; chaotic sequence is used to guide global search; and particle varies its positions via “flying”. With a typical 20-citys TSP as instance, the simulation experiment of comparing ICPSO with GA is carried out. Experimental results demonstrate that ICPSO is simple but effective, and better than GA at performance.
On exact statistics and classification of ergodic systems of integer dimension
Guralnik, Zachary Guralnik, Gerald; Pehlevan, Cengiz
2014-06-01
We describe classes of ergodic dynamical systems for which some statistical properties are known exactly. These systems have integer dimension, are not globally dissipative, and are defined by a probability density and a two-form. This definition generalizes the construction of Hamiltonian systems by a Hamiltonian and a symplectic form. Some low dimensional examples are given, as well as a discretized field theory with a large number of degrees of freedom and a local nearest neighbor interaction. We also evaluate unequal-time correlations of these systems without direct numerical simulation, by Padé approximants of a short-time expansion. We briefly speculate on the possibility of constructing chaotic dynamical systems with non-integer dimension and exactly known statistics. In this case there is no probability density, suggesting an alternative construction in terms of a Hopf characteristic function and a two-form.
NASA Astrophysics Data System (ADS)
Langel, Steven E.; Khanafseh, Samer M.; Pervan, Boris
2016-11-01
Differential carrier phase applications that utilize cycle resolution need the probability density function of the baseline estimate to quantify its region of concentration. For the integer bootstrap estimator, the density function has an analytical definition that enables probability calculations given perfect statistical knowledge of measurement and process noise. This paper derives a method to upper bound the tail probability of the integer bootstrapped GNSS baseline when the measurement and process noise correlation functions are unknown, but can be upper and lower bounded. The tail probability is shown to be a non-convex function of a vector of conditional variances, whose feasible region is a convex polytope. We show how to solve the non-convex optimization problem globally by discretizing the polytope into small hyper-rectangular elements, and demonstrate the method for a static baseline estimation problem.
Effect of Artocarpus integer lectin on functional activity of guinea-pig complement.
Hashim, O H; Gendeh, G S; Cheong, C N; Jaafar, M I
1994-03-01
The effect of Artocarpus integer lectin (lectin C) on the functional activity of guinea-pig complement was investigated. Purified and crude extract of lectin C from six cultivars of Artocarpus integer seeds were found to consume complement and thus decreased the complement-induced haemolytic activity of sensitized sheep erythrocytes. The change in the complement-mediated haemolytic activity was significantly decreased when incubation of the lectins was performed in the presence of melibiose. The reversal effect of the carbohydrate, which is a potent inhibitor of the lectin's binding to O-linked oligosaccharides of glycoprotein, demonstrate involvement of the lectins interaction with O-glycans of glycoproteins in the consumption of guinea-pig complement.
NASA Astrophysics Data System (ADS)
Bostan, Mohamad; Hadi Afshar, Mohamad; Khadem, Majed
2015-04-01
This article proposes a hybrid linear programming (LP-LP) methodology for the simultaneous optimal design and operation of groundwater utilization systems. The proposed model is an extension of an earlier LP-LP model proposed by the authors for the optimal operation of a set of existing wells. The proposed model can be used to optimally determine the number, configuration and pumping rates of the operational wells out of potential wells with fixed locations to minimize the total cost of utilizing a two-dimensional confined aquifer under steady-state flow conditions. The model is able to take into account the well installation, piping and pump installation costs in addition to the operational costs, including the cost of energy and maintenance. The solution to the problem is defined by well locations and their pumping rates, minimizing the total cost while satisfying a downstream demand, lower/upper bound on the pumping rates, and lower/upper bound on the water level drawdown at the wells. A discretized version of the differential equation governing the flow is first embedded into the model formulation as a set of additional constraints. The resulting mixed-integer highly constrained nonlinear optimization problem is then decomposed into two subproblems with different sets of decision variables, one with a piezometric head and the other with the operational well locations and the corresponding pumping rates. The binary variables representing the well locations are approximated by a continuous variable leading to two LP subproblems. Having started with a random value for all decision variables, the two subproblems are solved iteratively until convergence is achieved. The performance and ability of the proposed method are tested against a hypothetical problem from the literature and the results are presented and compared with those obtained using a mixed-integer nonlinear programming method. The results show the efficiency and effectiveness of the proposed method for
Topologically induced fractional Hall steps in the integer quantum Hall regime of MoS 2
NASA Astrophysics Data System (ADS)
Firoz Islam, SK; Benjamin, Colin
2016-09-01
The quantum magnetotransport properties of a monolayer of molybdenum disulfide are derived using linear response theory. In particular, the effect of topological terms on longitudinal and Hall conductivity is analyzed. The Hall conductivity exhibits fractional steps in the integer quantum Hall regime. Further complete spin and valley polarization of the longitudinal conductivitity is seen in presence of these topological terms. Finally, the Shubnikov-de Hass oscillations are suppressed or enhanced contingent on the sign of these topological terms.
Topologically induced fractional Hall steps in the integer quantum Hall regime of MoS 2.
Islam, S K Firoz; Benjamin, Colin
2016-09-23
The quantum magnetotransport properties of a monolayer of molybdenum disulfide are derived using linear response theory. In particular, the effect of topological terms on longitudinal and Hall conductivity is analyzed. The Hall conductivity exhibits fractional steps in the integer quantum Hall regime. Further complete spin and valley polarization of the longitudinal conductivitity is seen in presence of these topological terms. Finally, the Shubnikov-de Hass oscillations are suppressed or enhanced contingent on the sign of these topological terms.
Core barrier formation near integer q surfaces in DIII-D
Austin, M. E.; Gentle, K. W.; Burrell, K. H.; Waltz, R. E.; Gohil, P.; Greenfield, C. M.; Groebner, R. J.; Petty, C. C.; Prater, R.; Heidbrink, W. W.; Luo, Y.; Kinsey, J. E.; Makowski, M. A.; McKee, G. R.; Shafer, M. W.; Nazikian, R.; Rhodes, T. L.; Van Zeeland, M. A.
2006-08-15
Recent DIII-D experiments have significantly improved the understanding of internal transport barriers (ITBs) that are triggered close to the time when an integer value of the minimum in q is crossed. While this phenomenon has been observed on many tokamaks, the extensive transport and fluctuation diagnostics on DIII-D have permitted a detailed study of the generation mechanisms of q-triggered ITBs as pertaining to turbulence suppression dynamics, shear flows, and energetic particle modes. In these discharges, the evolution of the q profile is measured using motional Stark effect polarimetry and the integer q{sub min} crossings are further pinpointed in time by the observation of Alfven cascades. High time resolution measurements of the ion and electron temperatures and the toroidal rotation show that the start of improved confinement is simultaneous in all three channels, and that this event precedes the traversal of integer q{sub min} by 5-20 ms. There is no significant low-frequency magnetohydrodynamic activity prior to or just after the crossing of the integer q{sub min} and hence magnetic reconnection is determined not to be the precipitant of the confinement change. Instead, results from the GYRO code point to the effects of zonal flows near low order rational q values as playing a role in ITB triggering. A reduction in local turbulent fluctuations is observed at the start of the temperature rise and, concurrently, an increase in turbulence poloidal flow velocity and flow shear is measured with the beam emission spectroscopy diagnostic. For the case of a transition to an enduring internal barrier the fluctuation level remains at a reduced amplitude. The timing and nature of the temperature, rotation, and fluctuation changes leading to internal barriers suggests transport improvement due to increased shear flow arising from the zonal flow structures.
Topologically induced fractional Hall steps in the integer quantum Hall regime of MoS 2.
Islam, S K Firoz; Benjamin, Colin
2016-09-23
The quantum magnetotransport properties of a monolayer of molybdenum disulfide are derived using linear response theory. In particular, the effect of topological terms on longitudinal and Hall conductivity is analyzed. The Hall conductivity exhibits fractional steps in the integer quantum Hall regime. Further complete spin and valley polarization of the longitudinal conductivitity is seen in presence of these topological terms. Finally, the Shubnikov-de Hass oscillations are suppressed or enhanced contingent on the sign of these topological terms. PMID:27533362
Verslycke, Tim; Poelmans, Sofie; De Wasch, Katia; Vercauteren, Jordy; Devos, Christophe; Moens, Luc; Sandra, Patrick; De Brabander, Hubert F; Janssen, Colin R
2003-09-01
Current evidence suggests that the biocide tributyltin (TBT) causes the development of imposex, a state of pseudohermaphrodism in which females exhibit functional secondary male characteristics, by altering the biotransformation or elimination of testosterone. Imposex in gastropods following TBT exposure is the most complete example of the effects of an endocrine disrupter on marine invertebrates. Previous studies have demonstrated that the estuarine mysid Neomysis integer converts testosterone into multiple polar and nonpolar metabolites resulting from both phase I and phase II biotransformations. In this study, the effects of TBT chloride (TBTCl) on the phase I and II testosterone metabolism of N. integer were evaluated. The TBTCl was highly toxic to N. integer (96-h median lethal concentration [LC50] of 164 ng/L). To assess the effects on testosterone metabolism, mysids were exposed for 96 h to different concentrations of TBTCl (control, 10, 100, and 1,000 ng/L), and testosterone elimination as polar hydroxylated, nonpolar oxido-reduced, and glucose- and sulfate-conjugated metabolites was examined. The TBTCl differentially affected testosterone metabolism. The effect of TBTCl on phase I metabolism was unclear and has been shown to vary among species, likely depending on the inducibility or presence of certain P450 isozyme families. Reductase activity and metabolic androgenization were induced in the 10-ng/L treatment, whereas higher concentrations resulted in a reduction of sulfate conjugation. The exact mechanisms underlying TBT-induced imposex and alterations in the steroid metabolism need to be further elucidated. PMID:12959527
Two-dimensional integer wavelet transform with reduced influence of rounding operations
NASA Astrophysics Data System (ADS)
Strutz, Tilo; Rennert, Ines
2012-12-01
If a system for lossless compression of images applies a decorrelation step, this step must map integer input values to integer output values. This can be achieved, for example, using the integer wavelet transform (IWT). The non-linearity, introduced by the obligatory rounding steps, is the main drawback of the IWT, since it deteriorates the desired filter characteristic. This paper discusses different methods for reducing the influence of rounding in 5/3 and 9/7 filter banks. A novel combination of two-dimensional implementations of the JPEG2000 9/7 filter bank with new filter coefficients is proposed and the effects of the methods on lossless image compression are investigated. In addition, these filter banks are compared to the 9/7 Deslauriers-Dubuc filter bank (97DD). The analysed two-dimensional implementations generally perform better than their one-dimensional counterparts in terms of compression ratio for natural images. On average, the 2D 97DD filter bank performs best. In addition, it has been found that the compression results cannot be improved by simply reducing the number of lifting steps via 2D implementations of the JPEG2000 9/7 filter bank. Only the 2D implementation with a minimum number of lifting steps, in combination with modified lifting coefficients, leads to fewer bits per pixel than the separable implementation on average for a selected set of images.
Chen, Diyi; Zhang, Runfan; Sprott, J C; Chen, Haitao; Ma, Xiaoyi
2012-06-01
In this paper, we focus on the synchronization between integer-order chaotic systems and a class of fractional-order chaotic system using the stability theory of fractional-order systems. A new sliding mode method is proposed to accomplish this end for different initial conditions and number of dimensions. More importantly, the vector controller is one-dimensional less than the system. Furthermore, three examples are presented to illustrate the effectiveness of the proposed scheme, which are the synchronization between a fractional-order Chen chaotic system and an integer-order T chaotic system, the synchronization between a fractional-order hyperchaotic system based on Chen's system and an integer-order hyperchaotic system, and the synchronization between a fractional-order hyperchaotic system based on Chen's system and an integer-order Lorenz chaotic system. Finally, numerical results are presented and are in agreement with theoretical analysis.
Kill the song—steal the show: what does distinguish predicative metaphors from decomposable idioms?
Caillies, Stéphanie; Declercq, Christelle
2011-06-01
This study examined the semantic processing difference between decomposable idioms and novel predicative metaphors. It was hypothesized that idiom comprehension results from the retrieval of a figurative meaning stored in memory, that metaphor comprehension requires a sense creation process and that this process difference affects the processing time of idiomatic and metaphoric expressions. In the first experiment, participants read sentences containing decomposable idioms, predicative metaphors or control expressions and performed a lexical decision task on figurative targets presented 0, 350, and 500 ms, or 750 after reading. Results demonstrated that idiomatic expressions were processed sooner than metaphoric ones. In the second experiment, participants were asked to assess the meaningfulness of idiomatic, metaphoric and literal expressions after reading a verb prime that belongs to the target phrase (identity priming). The results showed that verb identity priming was stronger for idiomatic expressions than for metaphor ones, indicating different mental representations.
The relative ability of fungi from Sphagnum fuscum to decompose selected carbon substrates.
Thormann, Markus N; Currah, Randolph S; Bayley, Suzanne E
2002-03-01
Nine species from a suite of 55 microfungi isolated from living and decomposing Sphagnum fuscum were selected for studies of in vitro decomposition of tannic acid, cellulose, and starch. In vitro decomposition of S. fuscum plants and spruce wood chips was also examined. Oidiodendron maius and Oidiodendron scytaloides degraded tannic acid, giving a positive reaction for polyphenol oxidases. Most taxa degraded cellulose and starch via the synthesis of cellulases and amylase, respectively. Mass losses of spruce wood chips generally exceeded those of S. fuscum. A basidiomycete, similar to Bjerkandera adusta, caused the greatest mass losses in spruce wood chips (10.2%), while O. scytaloides caused the smallest mass losses (3.4%) after 8 weeks. For S. fuscum, Sordaria fimicola caused the greatest (5.1%) and Mucor hiemalis the smallest (0.1%) mass losses after 8 weeks. Filamentous microfungi have considerable potential to decompose a variety of carbon substrates of bryophilous residues in peatlands.
Why does Kevlar decompose, while Nomex does not, when treated with aqueous chlorine solutions?
Akdag, Akin; Kocer, Hasan B; Worley, S D; Broughton, R M; Webb, T R; Bray, Travis H
2007-05-24
Kevlar and Nomex are high-performance polymers which have wide varieties of applications in daily life. Recently, they have been proposed to be biocidal materials when reacted with household bleach (sodium hypochlorite solution) because they contain amide moieties which can be chlorinated to generate biocidal N-halamine functional groups. Although Nomex can be chlorinated without any significant decomposition, Kevlar decomposes under the same chlorination conditions. In this study, two mimics for each of the polymers were synthesized to simulate the carboxylate and diaminophenylene components of the materials. It was found that the p-diaminophenylene component of the Kevlar mimic is oxidized to a quinone-type structure upon treatment with hypochlorous acid, which then decomposes. However, such a mechanism for the Nomex mimic is not possible. In this paper, based upon these observations, a plausible answer will be provided to the title question.
Why does Kevlar decompose, while Nomex does not, when treated with aqueous chlorine solutions?
Akdag, Akin; Kocer, Hasan B; Worley, S D; Broughton, R M; Webb, T R; Bray, Travis H
2007-05-24
Kevlar and Nomex are high-performance polymers which have wide varieties of applications in daily life. Recently, they have been proposed to be biocidal materials when reacted with household bleach (sodium hypochlorite solution) because they contain amide moieties which can be chlorinated to generate biocidal N-halamine functional groups. Although Nomex can be chlorinated without any significant decomposition, Kevlar decomposes under the same chlorination conditions. In this study, two mimics for each of the polymers were synthesized to simulate the carboxylate and diaminophenylene components of the materials. It was found that the p-diaminophenylene component of the Kevlar mimic is oxidized to a quinone-type structure upon treatment with hypochlorous acid, which then decomposes. However, such a mechanism for the Nomex mimic is not possible. In this paper, based upon these observations, a plausible answer will be provided to the title question. PMID:17465537
Fernández, Diego; Tummala, Mallikarjun; Schreiner, Verena C; Duarte, Sofia; Pascoal, Cláudia; Winkelmann, Carola; Mewes, Daniela; Muñoz, Katherine; Schäfer, Ralf B
2016-05-01
Nutrient and pesticide pollution are widespread agricultural stressors. Fungicides may affect freshwater fungi, which play an important role in litter decomposition (LD), whereas moderate nutrient enrichment can stimulate LD. We examined potential interaction effects of nutrients and fungicides on decomposer communities and LD in a 14-day two-factorial (fungicide and nutrient treatments) mesocosm experiment. Fungicide exposure was limited to 4days to simulate episodic contamination. Only the microbial community responded significantly to the experimental factors, though non-significant increases >20% were found for invertebrate decomposer weight gain and LD under high-nutrient conditions. Fungal community structure responded more strongly to fungicides than sporulation. Sporulation responded strongest to nutrients. Bacterial community structure was affected by both factors, although only nutrients influenced bacterial density. Our results suggest effects from fungicides at field-relevant levels on the microbial community. Whether these changes propagate to invertebrate communities and LD remains unclear and should be analysed under longer and recurrent fungicide exposure.
NASA Astrophysics Data System (ADS)
Jain, Ashu; Srinivasulu, Sanaga
2006-02-01
This paper presents the findings of a study aimed at decomposing a flow hydrograph into different segments based on physical concepts in a catchment, and modelling different segments using different technique viz. conceptual and artificial neural networks (ANNs). An integrated modelling framework is proposed capable of modelling infiltration, base flow, evapotranspiration, soil moisture accounting, and certain segments of the decomposed flow hydrograph using conceptual techniques and the complex, non-linear, and dynamic rainfall-runoff process using ANN technique. Specifically, five different multi-layer perceptron (MLP) and two self-organizing map (SOM) models have been developed. The rainfall and streamflow data derived from the Kentucky River catchment were employed to test the proposed methodology and develop all the models. The performance of all the models was evaluated using seven different standard statistical measures. The results obtained in this study indicate that (a) the rainfall-runoff relationship in a large catchment consists of at least three or four different mappings corresponding to different dynamics of the underlying physical processes, (b) an integrated approach that models the different segments of the decomposed flow hydrograph using different techniques is better than a single ANN in modelling the complex, dynamic, non-linear, and fragmented rainfall runoff process, (c) a simple model based on the concept of flow recession is better than an ANN to model the falling limb of a flow hydrograph, and (d) decomposing a flow hydrograph into the different segments corresponding to the different dynamics based on the physical concepts is better than using the soft decomposition employed using SOM.
Persistence of spermatozoa on decomposing human skin: a scanning electron microscopy study.
Gibelli, D; Mazzarelli, D; Rizzi, A; Kustermann, A; Cattaneo, C
2013-09-01
Finding spermatozoa is of the utmost importance in judicial cases involving both the living and the dead; however, most of literature actually deals with inner genitalia and does not take into consideration the chance of external deposition of semen on skin, which is not rare. In addition, the most advanced microscopic technologies such as scanning electron microscopy (SEM) have not been thoroughly investigated within this specific field of research. This study aims at applying SEM analysis to samples of decomposed skin in order to test its potential in detecting spermatozoa particularly in decomposed cadavers. A sample of skin was obtained at autopsy and divided into two thin strips; one of the samples was used as a negative control. Semen was then taken from a "donor" (with a normal spermiogram) and was spread onto the other skin sample. Every 3 days for the first 15 days (for a total of six samples), a standard slide was prepared from swabs on the treated and control skin and analyzed by standard light microscopy. In addition, every 7 days up to 91 days (3 months circa), a skin sample was taken from the positive and negative control and examined by SEM for a total of 14 samples. Results show that after 12 days, light microscopy failed in detecting spermatozoa, whereas they were still visible up to 84 days by SEM analysis. This study therefore suggests the persistence of sperm structures in time and in decomposing material as well as the possible application of SEM technology to decomposed skin in order to detect semen.
NASA Astrophysics Data System (ADS)
Trandafir, Aurelian C.; Amini, Zahra A.
2009-05-01
Over the past decade, land development activities on hillsides in northern Utah have resulted in a significant increase in landslide activity throughout the region. The majority of recent landslides are shallow and they occurred on cut gentle slopes especially during spring and early summer due to snowmelt induced elevated groundwater tables. The geologic material documented at numerous landslide sites is a soft gray-green completely decomposed Norwood Tuff. The present study addresses the mechanism of a shallow landslide in completely decomposed Norwood Tuff based on field, laboratory and numerical investigations. Detailed slope surface geometry obtained from laser-scan surveys together with strength and stress-strain parameters derived from laboratory triaxial tests on undisturbed samples of completely decomposed Norwood Tuff collected from the landslide site are employed with finite-element modeling to examine the effects of ground surface deformation patterns on the yielding behavior of the slide mass. The numerical results indicate a gradual retreat of the yield zone with progressive landslide deformation, which eventually becomes concentrated within the accumulation zone of the landslide, compared to a well-developed yield zone within the entire slide mass at the onset of landslide movement. Limit equilibrium stability analyses along potential sliding surfaces of extent limited within the yield zone of the displaced slide mass produce lower safety factors than an analysis based on the original sliding surface comprising the entire slide mass.
Gomez, Pablo; Perea, Manuel
2014-01-01
In a diffusion model, performance as measured by latency and accuracy in two-choice tasks is decomposed into different parameters that can be linked to underlying cognitive processes. Although the diffusion model has been utilized to account for lexical decision data, the effects of stimulus manipulations in previous experiments originated from just one parameter: the quality of the evidence. Here we examined whether the diffusion model can be used to effectively decompose the underlying processes during visual-word recognition. We explore this issue in an experiment that features a lexical manipulation (word frequency) that we expected to affect mostly the quality of the evidence (the drift rate parameter), and a perceptual manipulation (stimulus orientation) that presumably affects the nondecisional time (the Ter parameter, time of encoding and response) more than it affects the drift rate. Results showed that although the manipulations do not affect only one parameter, word frequency and stimulus orientation had differential effects on the model's parameters. Thus, the diffusion model is a useful tool to decompose the effects of stimulus manipulations in visual-word recognition. PMID:25192455
Soil and decomposer responses to grazing exclusion are weak in mountain snow-beds
NASA Astrophysics Data System (ADS)
Virtanen, Risto; Salminen, Janne; Strömmer, Rauni
2008-03-01
Most of the empirical evidence available from different types of ecosystems have shown that aboveground plant-based and belowground decomposer systems are interconnected, and change in one leads to a response in the other. We analyzed responses of the soil decomposer system and soil decomposition processes to grazing exclusion and associated vegetation changes in a mountain snowbed. These habitats are of low productivity supporting bryophyte and graminoid-rich vegetation which is grazed by the Norwegian lemming and reindeer. We measured bacteria, enchytraeids, fungi, nematodes, microbial respiration, soil nitrogen (ammonium and nitrate), and soil water content from exclosure treatment plots of 5 and 15 years, where the exclusion of grazers had led to considerable vegetation changes. Soil decomposer variables showed only weak responses to the exclosure treatments or changes in aboveground vegetation (biomass and dead organic matter). Only nematodes responded positively to the short-term grazing exclusion. This suggests that above- and belowground processes are not necessarily closely interconnected in snowbed habitats and that the decomposition of plant material is directly controlled by grazer activity.
Kuske, C R; Ticknor, L O; Busch, J D; Gehring, C A; Whitham, T G
2003-05-01
In terrestrial ecosystems, changes in environmental conditions that affect plant performance cause a cascade of effects through many trophic levels. In a 2-year field study, seasonal abundance measurements were conducted for fast-growing bacterial heterotrophs, humate-degrading actinomycetes, fungal heterotrophs, and fluorescent pseudomonads that represent the decomposers in soil. Links between plant health and soil microbiota abundance in pinyon rhizospheres were documented across two soil types: a dry, nutrient-poor volcanic cinder field and a sandy-loam soil. On the stressful cinder fields, we identified relationships between soil decomposer abundance, pinyon age, and stress due to insect herbivory. Across seasonal variation, consistent differences in microbial decomposer abundance were identified between the cinders and sandy-loam soil. Abundance of bacterial heterotrophs and humate-degrading actinomycetes was affected by both soil nutritional status and the pinyon rhizosphere. In contrast, abundance of the fungal heterotrophs and fluorescent pseudomonads was affected primarily by the pinyon rhizosphere. On the cinder field, the three bacterial groups were more abundant on 150-year-old trees than on 60-year-old trees, whereas fungal heterotrophs were unaffected by tree age. Fungal heterotrophs and actinomycetes were more abundant on insect-resistant trees than on susceptible trees, but the opposite was true for the fluorescent pseudomonads. Although all four groups were present in all the environments, the four microbial groups were affected differently by the pinyon rhizosphere, by tree age, and by tree stress caused by the cinder soil and insect herbivory.
ERIC Educational Resources Information Center
Community College Journal, 1996
1996-01-01
Includes a collection of eight short articles describing model community college programs. Discusses a literacy program, a mobile computer classroom, a support program for at-risk students, a timber-harvesting program, a multimedia presentation on successful women graduates, a career center, a collaboration with NASA, and an Israeli engineering…
NASA Astrophysics Data System (ADS)
Deng, Nianpei
The two dimensional electron gas subjected to a magnetic field has been a model system in contemporary condensed matter physics which generated many beautiful experiments as well as novel fundamental concepts. These novel concepts are of broad interests and have benefited other fields of research. For example, the observations of conventional odd-denominator fractional quantum Hall states have enriched many-body physics with important concepts such as fractional statistics and composite fermions. The subsequent discovery of the enigmatic even-denominator nu=5/2 fractional quantum Hall state has led to more interesting concepts such as non-Abelian statistics and pairing of composite fermions which can be intimately connected to the electron pairing in superconductivity. Moreover, the observations of stripe phases and reentrant integer quantum Hall states have stimulated research on exotic electron solids which have more intricate structures than the Wigner Crystal. In contrast to fractional quantum Hall states and stripes phases, the reentrant integer quantum Hall states are very little studied and their ground states are the least understood. There is a lack of basic information such as exact filling factors, temperature dependence and energy scales for the reentrant integer quantum Hall states. A critical experimental condition in acquiring this information is a stable ultra-low temperature environment. In the first part of this dissertation, I will discuss our unique setup of 3He immersion cell in a state-of-art dilution refrigerator which achieves the required stability of ultra-low temperature. With this experimental setup, we are able to observe for the first time very sharp magnetotransport features of reentrant integer quantum Hall states across many Landau levels for the first time. I will firstly present our results in the second Landau level. The temperature dependence measurements reveal a surprisingly sharp peak signature that is unique to the reentrant
Improvement of PPP-inferred tropospheric estimates by integer ambiguity resolution
NASA Astrophysics Data System (ADS)
Shi, J.; Gao, Y.
2012-11-01
Integer ambiguity resolution in Precise Point Positioning (PPP) can improve positioning accuracy and reduce convergence time. The decoupled clock model proposed by Collins (2008) has been used to facilitate integer ambiguity resolution in PPP, and research has been conducted to assess the model's potential to improve positioning accuracy and reduce positioning convergence time. In particular, the biggest benefits have been identified for the positioning solutions within short observation periods such as one hour. However, there is little work reported about the model's potential to improve the estimation of the tropospheric parameter within short observation periods. This paper investigates the effect of PPP ambiguity resolution on the accuracy of the tropospheric estimates within one hour. The tropospheric estimates with float and fixed ambiguities within one hour are compared to two external references. The first reference is the International GNSS Service (IGS) final troposphere product based on the PPP technique. The second reference is the Constellation Observing System for Meteorology Ionosphere and Climate (COSMIC) radio occultation (RO) event based on the atmospheric profiles along the signal travel path. A comparison among ten co-located ground-based GPS and space-based RO troposphere zenith path delays shows that the mean bias of the troposphere estimates with float ambiguities can be significantly reduced from 30.1 to 17.0 mm when compared to the IGS troposphere product and from 36.3 to 19.7 mm when compared to the COSMIC RO. The root mean square (RMS) accuracy improvement of the tropospheric parameters by the ambiguity resolution is 33.3% when compared to the IGS products and 44.3% when compared to the COSMIC RO. All these improvements are achieved within one hour, which indicates the promising prospect of adopting PPP integer ambiguity resolution for time-critical applications such as typhoon prediction.
Integer cosine transform compression for Galileo at Jupiter: A preliminary look
NASA Technical Reports Server (NTRS)
Ekroot, L.; Dolinar, S.; Cheung, K.-M.
1993-01-01
The Galileo low-gain antenna mission has a severely rate-constrained channel over which we wish to send large amounts of information. Because of this link pressure, compression techniques for image and other data are being selected. The compression technique that will be used for images is the integer cosine transform (ICT). This article investigates the compression performance of Galileo's ICT algorithm as applied to Galileo images taken during the early portion of the mission and to images that simulate those expected from the encounter at Jupiter.
Asymptotic stabilisation for a class of feedforward input-delay systems with ratios of odd integers
NASA Astrophysics Data System (ADS)
Wu, Jian; Chen, Weisheng; Miao, Qiguang
2013-11-01
This article addresses the stabilisation problem by state-feedback for a class of feedforward input-delay nonlinear systems with ratios of odd integer powers. The designed controller achieves the global asymptotic stability. Based on the appropriate state transformation of time-delay systems and the Lyapunov method, the problem of controller design can be converted into the problem of finding a parameter which can be obtained by appraising the nonlinear terms of the systems. Finally, three simulation examples are given to illustrate the effectiveness of the control algorithm proposed in this article.
Is integer arithmetic fundamental to mental processing?: the mind's secret arithmetic.
Snyder, A W; Mitchell, D J
1999-01-01
Unlike the ability to acquire our native language, we struggle to learn multiplication and division. It may then come as a surprise that the mental machinery for performing lightning-fast integer arithmetic calculations could be within us all even though it cannot be readily accessed, nor do we have any idea of its primary function. We are led to this provocative hypothesis by analysing the extraordinary skills of autistic savants. In our view such individuals have privileged access to lower levels of information not normally available through introspection. PMID:10212449
Integer quantum Hall effect on a six-valley hydrogen-passivated silicon (111) surface.
Eng, K; McFarland, R N; Kane, B E
2007-07-01
We report magnetotransport studies of a two-dimensional electron system formed in an inversion layer at the interface between a hydrogen-passivated Si(111) surface and vacuum. Measurements in the integer quantum Hall regime demonstrate that the expected sixfold valley degeneracy for these surfaces is broken, resulting in an unequal occupation of the six valleys and anisotropy in the resistance. We hypothesize the misorientation of Si surface breaks the valley states into three unequally spaced pairs, but the observation of odd filling factors is difficult to reconcile with noninteracting electron theory.
Fast-Polynomial-Transform Program
NASA Technical Reports Server (NTRS)
Truong, T. K.; Hsu, I. S.; Chu, Y. F.
1987-01-01
Computer program uses fast-polynomial-transformation (FPT) algorithm applicable to two-dimensional mathematical convolutions. Two-dimensional cyclic convolutions converted to one-dimensional convolutions in polynomial rings. Program decomposes cyclic polynomials into polynomial convolutions of same length. Only FPT's and fast Fourier transforms of same length required. Modular approach saves computional resources. Program written in C.
Dunn, Abe; Shapiro, Adam Hale; Liebman, Eli
2013-12-01
This study introduces a new framework for measuring and analyzing medical-care expenditures. The framework focuses on expenditures at the disease level that are decomposed between price and utilization. We find that both price and utilization differences are important contributors to expenditure differences across commercial markets. Further examination shows that for some diseases utilization drives variation while for others price is more important. Finally, when disease-specific measures are aggregated across diseases, much of the important disease-specific variation is masked, leading to much smaller measures of aggregate variation.
Identifying the biotic (e.g. decomposers, vegetation) and abiotic (e.g. temperature, moisture) mechanisms controlling litter decomposition is key to understanding ecosystem function, especially where variation in ecosystem structure due to successional processes may alter the str...
Deniz, Furkan Nur; Alagoz, Baris Baykant; Tan, Nusret; Atherton, Derek P
2016-05-01
This paper introduces an integer order approximation method for numerical implementation of fractional order derivative/integrator operators in control systems. The proposed method is based on fitting the stability boundary locus (SBL) of fractional order derivative/integrator operators and SBL of integer order transfer functions. SBL defines a boundary in the parametric design plane of controller, which separates stable and unstable regions of a feedback control system and SBL analysis is mainly employed to graphically indicate the choice of controller parameters which result in stable operation of the feedback systems. This study reveals that the SBL curves of fractional order operators can be matched with integer order models in a limited frequency range. SBL fitting method provides straightforward solutions to obtain an integer order model approximation of fractional order operators and systems according to matching points from SBL of fractional order systems in desired frequency ranges. Thus, the proposed method can effectively deal with stability preservation problems of approximate models. Illustrative examples are given to show performance of the proposed method and results are compared with the well-known approximation methods developed for fractional order systems. The integer-order approximate modeling of fractional order PID controllers is also illustrated for control applications. PMID:26876378
A FPGA system for QRS complex detection based on Integer Wavelet Transform
NASA Astrophysics Data System (ADS)
Stojanović, R.; Karadaglić, D.; Mirković, M.; Milošević, D.
2011-01-01
Due to complexity of their mathematical computation, many QRS detectors are implemented in software and cannot operate in real time. The paper presents a real-time hardware based solution for this task. To filter ECG signal and to extract QRS complex it employs the Integer Wavelet Transform. The system includes several components and is incorporated in a single FPGA chip what makes it suitable for direct embedding in medical instruments or wearable health care devices. It has sufficient accuracy (about 95%), showing remarkable noise immunity and low cost. Additionally, each system component is composed of several identical blocks/cells what makes the design highly generic. The capacity of today existing FPGAs allows even dozens of detectors to be placed in a single chip. After the theoretical introduction of wavelets and the review of their application in QRS detection, it will be shown how some basic wavelets can be optimized for easy hardware implementation. For this purpose the migration to the integer arithmetic and additional simplifications in calculations has to be done. Further, the system architecture will be presented with the demonstrations in both, software simulation and real testing. At the end, the working performances and preliminary results will be outlined and discussed. The same principle can be applied with other signals where the hardware implementation of wavelet transform can be of benefit.
Design of real-time video watermarking based on Integer DCT for H.264 encoder
NASA Astrophysics Data System (ADS)
Joshi, Amit M.; Mishra, Vivekanand; Patrikar, R. M.
2015-01-01
With the advent of technology, video has become a prominent entity that is shared over networks. With easy availability of various editing tools, data integrity and ownership issues have caused great concern worldwide. Video watermarking is an evolving field that may be used to address such issues. Till date, most of the algorithms have been developed for uncompressed domain watermarking and implemented on software platforms. They provide flexibility and simplicity, but at the same time, they are not suited for real-time applications. They work offline where videos are captured and then watermark is embedded in the video. In the present work, a hardware-based implementation of video watermarking is proposed that overcomes the limitation of software watermarking methods and can be readily adapted to the H.264 standard. This paper focuses on an invisible and robust video watermarking scheme, which can be easily implemented as an integral part of the standard H.264 encoder. The proposed watermarking algorithm involves Integer DCT-based watermark embedding method, wherein Integer DCT is calculated with a fully parallel approach resulting in better speed. The proposed video watermarking is designed with pipelining and parallel architecture for real-time implementation. Here, scene change detection technique is used to improve the performance. Different planes of the watermark are embedded in different frames of a particular scene in order to achieve robustness against various temporal attacks.
Half integer features in the quantum Hall Effect: experiment and theory
NASA Astrophysics Data System (ADS)
Kramer, Tobias; Heller, E. J.; Parrott, R. E.; Liang, C.-T.; Huang, C. F.; Chen, K. Y.; Lin, L.-H.; Wu, J.-Y.; Lin, S.-D.
2009-03-01
We discuss experimental data and a new model of the integer quantum Hall effect (IQHE), which explains an intriguing substructure within Landau levels observed at higher currents. The experiments show inflection points in the Hall resistivity around filling factors 5/2 and 7/2. The experiments require to revisit the foundations of the IQHE and to establish an injection model which incorporates the correct boundary conditions imposed by a real Hall device and the Lorentz force. We have to follow the electrons to their source: one corner of the Hall bar and its steep electric field gradients, rather than focusing on the middle of the Hall device. We find the entire Hall resistivity curve is calculable as a function of magnetic field, temperature, and current. In contrast to previous theories of the IQHE, disorder plays no fundamental role in our theory. Contrary to the standard picture of Landau levels in disorder system, we predict and observe gaps right in the middle of certain Landau levels. The Hall plateaus and half integer inflections are shown to result from the LDOS appropriate to the magnetic field and the strong electric field at the injection corner.
A simplified Integer Cosine Transform and its application in image compression
NASA Technical Reports Server (NTRS)
Costa, M.; Tong, K.
1994-01-01
A simplified version of the integer cosine transform (ICT) is described. For practical reasons, the transform is considered jointly with the quantization of its coefficients. It differs from conventional ICT algorithms in that the combined factors for normalization and quantization are approximated by powers of two. In conventional algorithms, the normalization/quantization stage typically requires as many integer divisions as the number of transform coefficients. By restricting the factors to powers of two, these divisions can be performed by variable shifts in the binary representation of the coefficients, with speed and cost advantages to the hardware implementation of the algorithm. The error introduced by the factor approximations is compensated for in the inverse ICT operation, executed with floating point precision. The simplified ICT algorithm has potential applications in image-compression systems with disparate cost and speed requirements in the encoder and decoder ends. For example, in deep space image telemetry, the image processors on board the spacecraft could take advantage of the simplified, faster encoding operation, which would be adjusted on the ground, with high-precision arithmetic. A dual application is found in compressed video broadcasting. Here, a fast, high-performance processor at the transmitter would precompensate for the factor approximations in the inverse ICT operation, to be performed in real time, at a large number of low-cost receivers.
Optimal integer resolution for attitude determination using global positioning system signals
NASA Technical Reports Server (NTRS)
Crassidis, John L.; Markley, F. Landis; Lightsey, E. Glenn
1998-01-01
In this paper, a new motion-based algorithm for GPS integer ambiguity resolution is derived. The first step of this algorithm converts the reference sightline vectors into body frame vectors. This is accomplished by an optimal vectorized transformation of the phase difference measurements. The result of this transformation leads to the conversion of the integer ambiguities to vectorized biases. This essentially converts the problem to the familiar magnetometer-bias determination problem, for which an optimal and efficient solution exists. Also, the formulation in this paper is re-derived to provide a sequential estimate, so that a suitable stopping condition can be found during the vehicle motion. The advantages of the new algorithm include: it does not require an a-priori estimate of the vehicle's attitude; it provides an inherent integrity check using a covariance-type expression; and it can sequentially estimate the ambiguities during the vehicle motion. The only disadvantage of the new algorithm is that it requires at least three non-coplanar baselines. The performance of the new algorithm is tested on a dynamic hardware simulator.
On P -orderings, rings of integer-valued polynomials, and ultrametric analysis
NASA Astrophysics Data System (ADS)
Bhargava, Manjul
2009-10-01
We introduce two new notions of `` P -ordering'' and use them to define a three-parameter generalization of the usual factorial function. We then apply these notions of P -orderings and factorials to some classical problems in two distinct areas, namely: 1) the study of integer-valued polynomials and 2) P -adic analysis. Specifically, we first use these notions of P -orderings and factorials to construct explicit Polya-style regular bases for two natural families of rings of integer-valued polynomials defined on an arbitrary subset of a Dedekind domain. Second, we classify ``smooth'' functions on an arbitrary compact subset S of a local field, by constructing explicit interpolation series (i.e., orthonormal bases) for the Banach space of functions on S satisfying any desired conditions of continuous differentiability or local analyticity. Our constructions thus extend Mahler's Theorem (classifying the functions that are continuous on {Z}_p ) to a very general setting. In particular, our constructions prove that, for any epsilon>0 , the functions in any of the above Banach spaces can be epsilon -approximated by polynomials (with respect to their respective Banach norms). Thus we obtain the non-Archimedean analogues of the classical polynomial approximation theorems in real and complex analysis proven by Weierstrass, de la Vallee-Poussin, and Bernstein. Our proofs are effective.
Broniatowski, Marcin; Sobolewska, Katarzyna; Flasiński, Michał; Wydro, Paweł
2016-04-01
Bisphenol A (BPA) and other bisphenols constitute a class of organic pollutants, which because of their estrogenic properties, low dose activity and bioaccumulation pose considerable risk for public health as well as for the environment. Accumulated in the sediment bisphenols can endanger the decomposers' populations being incorporated into their cellular membranes; however, the mechanism of their membrane activity is unknown. Therefore, to study these phenomena we applied anionic phospholipid Langmuir monolayers as simple but versatile models of decomposers biomembranes. Phosphatidylglycerols and cardiolipins are not only the main components of bacterial membranes but also of crucial importance in mitochondrial and thylakoid membranes in eukaryotic cells. In our investigations we applied five compounds of the bisphenol class most commonly detected in the environment. To characterize the bisphenols-model membrane interactions we applied multiple mutually independent methods of physical chemistry; namely: the Langmuir monolayer technique, surface potential measurements, Brewster angle microscopy for the visualization of the monolayers' texture and grazing incidence X-ray diffraction for the discussion of the phospholipids packing within the monolayers. Our studies indicated that all the investigated bisphenols interact with the model membrane, but the strength of the interactions is dependent on the bisphenol structure and hydrophobicity and the fluidity of the model membranes. We proved that bisphenol S often treated as the least toxic BPA analog can also be incorporated to the model membranes changing their structure and fluidity. PMID:26806160
Shared processing of perception and imagery of music in decomposed EEG.
Schaefer, Rebecca S; Desain, Peter; Farquhar, Jason
2013-04-15
The current work investigates the brain activation shared between perception and imagery of music as measured with electroencephalography (EEG). Meta-analyses of four separate EEG experiments are presented, each focusing on perception and imagination of musical sound, with differing levels of stimulus complexity. Imagination and perception of simple accented metronome trains, as manifested in the clock illusion, as well as monophonic melodies are discussed, as well as more complex rhythmic patterns and ecologically natural music stimuli. By decomposing the data with principal component analysis (PCA), similar component distributions are found to explain most of the variance in each experiment. All data sets show a fronto-central and a more central component as the largest sources of variance, fitting with projections seen for the network of areas contributing to the N1/P2 complex. We expanded on these results using tensor decomposition. This allows us to add in the tasks to find shared activation, but does not make assumptions of independence or orthogonality and calculates the relative strengths of these components for each task. The components found in the PCA were shown to be further decomposable into parts that load primarily on to the perception or imagery task, or both, thereby adding more detail. It is shown that the frontal and central components have multiple parts that are differentially active during perception and imagination. A number of possible interpretations of these results are discussed, taking into account the different stimulus materials and measurement conditions. PMID:23298753
NASA Astrophysics Data System (ADS)
Song, Linye; Duan, Wansuo; Li, Yun; Mao, Jiangyu
2016-09-01
A timescale decomposed threshold regression (TSDTR) downscaling approach to forecasting South China early summer rainfall (SCESR) is described by using long-term observed station rainfall data and NOAA ERSST data. It makes use of two distinct regression downscaling models corresponding to the interannual and interdecadal rainfall variability of SCESR. The two models are developed based on the partial least squares (PLS) regression technique, linking SCESR to SST modes in preceding months on both interannual and interdecadal timescales. Specifically, using the datasets in the calibration period 1915-84, the variability of SCESR and SST are decomposed into interannual and interdecadal components. On the interannual timescale, a threshold PLS regression model is fitted to interannual components of SCESR and March SST patterns by taking account of the modulation of negative and positive phases of the Pacific Decadal Oscillation (PDO). On the interdecadal timescale, a standard PLS regression model is fitted to the relationship between SCESR and preceding November SST patterns. The total rainfall prediction is obtained by the sum of the outputs from both the interannual and interdecadal models. Results show that the TSDTR downscaling approach achieves reasonable skill in predicting the observed rainfall in the validation period 1985-2006, compared to other simpler approaches. This study suggests that the TSDTR approach, considering different interannual SCESR-SST relationships under the modulation of PDO phases, as well as the interdecadal variability of SCESR associated with SST patterns, may provide a new perspective to improve climate predictions.
Mycorrhiza-mediated competition between plants and decomposers drives soil carbon storage.
Averill, Colin; Turner, Benjamin L; Finzi, Adrien C
2014-01-23
Soil contains more carbon than the atmosphere and vegetation combined. Understanding the mechanisms controlling the accumulation and stability of soil carbon is critical to predicting the Earth's future climate. Recent studies suggest that decomposition of soil organic matter is often limited by nitrogen availability to microbes and that plants, via their fungal symbionts, compete directly with free-living decomposers for nitrogen. Ectomycorrhizal and ericoid mycorrhizal (EEM) fungi produce nitrogen-degrading enzymes, allowing them greater access to organic nitrogen sources than arbuscular mycorrhizal (AM) fungi. This leads to the theoretical prediction that soil carbon storage is greater in ecosystems dominated by EEM fungi than in those dominated by AM fungi. Using global data sets, we show that soil in ecosystems dominated by EEM-associated plants contains 70% more carbon per unit nitrogen than soil in ecosystems dominated by AM-associated plants. The effect of mycorrhizal type on soil carbon is independent of, and of far larger consequence than, the effects of net primary production, temperature, precipitation and soil clay content. Hence the effect of mycorrhizal type on soil carbon content holds at the global scale. This finding links the functional traits of mycorrhizal fungi to carbon storage at ecosystem-to-global scales, suggesting that plant-decomposer competition for nutrients exerts a fundamental control over the terrestrial carbon cycle.
Toenails as an alternative source material for the extraction of DNA from decomposed human remains.
Schlenker, Andrew; Grimble, Katelyn; Azim, Arani; Owen, Rebecca; Hartman, Dadna
2016-01-01
The DNA identification of decomposed human remains for coronial investigations at the Victorian Institute of Forensic Medicine routinely requires the retrieval and processing of a bone sample obtained from the deceased. Bone is a difficult sample type to work with as it requires surgical removal from the deceased, refrigerated storage, and additional processing steps prior to DNA analysis in comparison to other samples types such as buccal swabs or blood stains. In an attempt to overcome the issues posed by bone, a DNA extraction method utilising toenails as an alternate source material was optimised and trialled. Two DNA extraction methods were optimised for digestion of toenail material, with the method utilising the QIAGEN DNA Investigator Kit selected for a casework trial. Single source DNA profiles, matching those of the conventional samples taken, were obtained for toenail samples collected from 28 of 30 coronial cases available for this study. Of these, 26 toenail samples produced full profiles. Although the overall DNA profile quality from the toenails was less than that of the conventional sample, the profiles from toenails met the reporting requirements for identification. Based on the results obtained, the Victorian Institute of Forensic Medicine will be implementing toenails as the primary sample type for collection from decomposed remains when blood is not a suitable sample type.
Using red clump stars to decompose the galactic magnetic field with distance
Pavel, Michael D.
2014-09-01
A new method for measuring the large-scale structure of the Galactic magnetic field is presented. The Galactic magnetic field has been probed through the Galactic disk with near-infrared starlight polarimetry; however, the distance to each background star is unknown. Using red clump stars as near-infrared standard candles, this work presents the first attempt to decompose the line-of-sight structure of the sky-projected Galactic magnetic field. Two example lines of sight are decomposed: toward a field with many red clump stars and toward a field with few red clump stars. A continuous estimate of magnetic field orientation over several kiloparsecs of distance is possible in the field with many red clump stars, while only discrete estimates are possible in the sparse example. Toward the outer Galaxy, there is a continuous field orientation with distance that shows evidence of perturbation by the Galactic warp. Toward the inner Galaxy, evidence for a large-scale change in the magnetic field geometry is consistent with models of magnetic field reversals, independently derived from Faraday rotation studies. A photo-polarimetric method for identifying candidate intrinsically polarized stars is also presented. The future application of this method to large regions of the sky will begin the process of mapping the Galactic magnetic field in a way never before possible.
A note on the optimality of decomposable entanglement witnesses and completely entangled subspaces
NASA Astrophysics Data System (ADS)
Augusiak, R.; Tura, J.; Lewenstein, M.
2011-05-01
Entanglement witnesses (EWs) constitute one of the most important entanglement detectors in quantum systems. Nevertheless, their complete characterization, in particular with respect to the notion of optimality, is still missing, even in the decomposable case. Here we show that for any qubit-qunit decomposable EW (DEW) W, the three statements are equivalent: (i) the set of product vectors obeying lange, f|W|e, frang = 0 spans the corresponding Hilbert space, (ii) W is optimal, and (iii) W = QΓ, with Q denoting a positive operator supported on a completely entangled subspace (CES) and Γ standing for the partial transposition. While implications (i)==>(ii) and (ii)==>(iii) are known, here we prove that (iii) implies (i). This is a consequence of a more general fact saying that product vectors orthogonal to any CES in {\\bb C}^{2}\\otimes {\\bb C}^{n} span after partial conjugation the whole space. On the other hand, already in the case of the {\\bb C}^{3}\\otimes {\\bb C}^{3} Hilbert space, there exist DEWs for which (iii) does not imply (i). Consequently, either (i) does not imply (ii) or (ii) does not imply (iii), and the above transparent characterization, obeyed by qubit-qunit DEWs, does not hold in general.
First-principles study of SF6 decomposed gas adsorbed on Au-decorated graphene
NASA Astrophysics Data System (ADS)
Zhang, Xiaoxing; Yu, Lei; Gui, Yingang; Hu, Weihua
2016-03-01
We theoretically investigated the decomposed gaseous components of sulfur hexafluoride (SF6), namely, H2S, SO2, SOF2, and SO2F2, adsorbed on pristine and Au-embedded graphene based on the revised Perdew-Burke-Ernzerhof calculation, which empirically includes a dispersion correction (DFT-D) for van der Waals interaction with standard generalized gradient approximation. Pristine graphene exhibits weak adsorption and absence of charge transfer, which indicates barely satisfactory sensing for decomposed components. The Au atom introduces magnetism to the pristine graphene after metal-embedded decoration as well as enhances conductivity. All four molecules induce certain hybridization between the molecules and Au-graphene, which results in chemical interactions. SOF2 and SO2F2 exhibit a strong chemisorption interaction with Au-graphene, while H2S and SO2 exhibit quasi-molecular binding effects. Only H2S exhibits n-type doping to Au-graphene, whereas the rest gases exhibit p-type doping. Magnetic moments fluctuate substantially in the original Au-graphene when H2S and SO2 are adsorbed. While the adsorption effects of SOF2 and SO2F2 generate magnetism quenching. The charge transfer mechanism is also discussed in this paper. These results will shed light on the valuable application of Au-embedded graphene for selective gas sensing and spintronics.
Tang, Fan; Hu, Hong-qing; Su, Xiao-juan; Fu, Qing-ling; Zhu, Jun
2015-08-01
The soils treated with phosphate rock (PR) and oxalic acid activated phosphate rock (APR) mixed with decomposed rice straw were incubated in different moisture conditions for 60 days to study the effect on the basic property of the soil and on the speciation variation of Pb. The results showed that all these three types of immobilizing materials increased the pH, the Olsen-P, the exchangeable Ca and the soil cation exchange capacity, and APR showed more obvious effect; the pH and the exchangeable Ca of soil in the flooding treatment were higher than those in normal water treatment (70%), but the Olsen-P of soil in normal water treatment was a little bit more. These materials reduced exchangeable Ph fraction, and converted it into unavailable fraction. But the APR was better than raw PR in immobilizing lead, and the exchangeable Pb fraction was reduced by 40.3% and 24.2%, compared with the control, respectively, and the immobilization effect was positively correlated with the dosage. Decomposed rice straw could transform the exchangeable Ph fraction in soil into organic-bound fraction, while the flooding treatment changed it into the Fe-Mn oxide-bound and residue fractions. PMID:26592041
Flury, Sabine; Gessner, Mark O
2011-02-01
Atmospheric warming and increased nitrogen deposition can lead to changes of microbial communities with possible consequences for biogeochemical processes. We used an enclosure facility in a freshwater marsh to assess the effects on microbes associated with decomposing plant litter under conditions of simulated climate warming and pulsed nitrogen supply. Standard batches of litter were placed in coarse-mesh and fine-mesh bags and submerged in a series of heated, nitrogen-enriched, and control enclosures. They were retrieved later and analyzed for a range of microbial parameters. Fingerprinting profiles obtained by denaturing gradient gel electrophoresis (DGGE) indicated that simulated global warming induced a shift in bacterial community structure. In addition, warming reduced fungal biomass, whereas bacterial biomass was unaffected. The mesh size of the litter bags and sampling date also had an influence on bacterial community structure, with the apparent number of dominant genotypes increasing from spring to summer. Microbial respiration was unaffected by any treatment, and nitrogen enrichment had no clear effect on any of the microbial parameters considered. Overall, these results suggest that microbes associated with decomposing plant litter in nutrient-rich freshwater marshes are resistant to extra nitrogen supplies but are likely to respond to temperature increases projected for this century.
Gauge-invariant dynamical quantities of QED with decomposed gauge potentials
Zhou Baohua; Huang Yongchang
2011-09-15
We discover an inner structure of the QED system; i.e., by decomposing the gauge potential into two orthogonal components, we obtain a new expansion of the Lagrangian for the electron-photon system, from which, we realize the orthogonal decomposition of the canonical momentum conjugate to the gauge potential with the canonical momentum's two components conjugate to the gauge potential's two components, respectively. Using the new expansion of Lagrangian and by the general method of field theory, we naturally derive the gauge invariant separation of the angular momentum of the electron-photon system from Noether theorem, which is the rational one and has the simplest form in mathematics, compared with the other four versions of the angular momentum separation available in literature. We show that it is only the longitudinal component of the gauge potential that is contained in the orbital angular momentum of the electron, as Chen et al. have said. A similar gauge invariant separation of the momentum is given. The decomposed canonical Hamiltonian is derived, from which we construct the gauge invariant energy operator of the electron moving in the external field generated by a proton [Phys. Rev. A 82, 012107 (2010)], where we show that the form of the kinetic energy containing the longitudinal part of the gauge potential is due to the intrinsic requirement of the gauge invariance. Our method provides a new perspective to look on the nucleon spin crisis and indicates that this problem can be solved strictly and systematically.
Fernández, Diego; Tummala, Mallikarjun; Schreiner, Verena C; Duarte, Sofia; Pascoal, Cláudia; Winkelmann, Carola; Mewes, Daniela; Muñoz, Katherine; Schäfer, Ralf B
2016-05-01
Nutrient and pesticide pollution are widespread agricultural stressors. Fungicides may affect freshwater fungi, which play an important role in litter decomposition (LD), whereas moderate nutrient enrichment can stimulate LD. We examined potential interaction effects of nutrients and fungicides on decomposer communities and LD in a 14-day two-factorial (fungicide and nutrient treatments) mesocosm experiment. Fungicide exposure was limited to 4days to simulate episodic contamination. Only the microbial community responded significantly to the experimental factors, though non-significant increases >20% were found for invertebrate decomposer weight gain and LD under high-nutrient conditions. Fungal community structure responded more strongly to fungicides than sporulation. Sporulation responded strongest to nutrients. Bacterial community structure was affected by both factors, although only nutrients influenced bacterial density. Our results suggest effects from fungicides at field-relevant levels on the microbial community. Whether these changes propagate to invertebrate communities and LD remains unclear and should be analysed under longer and recurrent fungicide exposure. PMID:26963520
Osono, Takashi; Takeda, Hiroshi
2002-01-01
The litter decomposing ability of 79 fungal isolates (41 genera, 60 species) was assessed with the pure culture decomposition test. The isolates were collected qualitatively in a cool temperate deciduous forest in Japan during a 21-mo period. Loss of original weight of sterilized litter ranged from 0.1% to 57.6%. Six isolates in the Basidiomycota caused high weight losses ranging from 15.1% to 57.6%. Fourteen isolates in Xylaria and Geniculosporium (the Xylariaceae and its anamorph) also caused high weight losses ranging from 4.0% to 14.4%. Other isolates in the Ascomycota and associated anamorphs and in the Zygomycota caused low weight losses on mean. Six fungi in the Basidiomycota, and all in the Xylariaceae showed a bleaching activity of the litter and caused lignin and carbohydrate decomposition. Mean lignin/weight loss ratios (L/W) and lignin/carbohydrate loss ratios (L/C), were 0.9 and 0.7 for the Basidiomycota and 0.7 and 0.4 for the Xylariaceae, respectively. Significant differences were found in L/W and L/C between the two groups when the result of Xylaria sp. that showed marked delignification was excluded. These differences in lignin and carbohydrate utilization patterns are discussed in relation to the structural and the chemical properties of the decomposed litter and to the implications for organic chemical changes during litter decomposition processes.
Broniatowski, Marcin; Sobolewska, Katarzyna; Flasiński, Michał; Wydro, Paweł
2016-04-01
Bisphenol A (BPA) and other bisphenols constitute a class of organic pollutants, which because of their estrogenic properties, low dose activity and bioaccumulation pose considerable risk for public health as well as for the environment. Accumulated in the sediment bisphenols can endanger the decomposers' populations being incorporated into their cellular membranes; however, the mechanism of their membrane activity is unknown. Therefore, to study these phenomena we applied anionic phospholipid Langmuir monolayers as simple but versatile models of decomposers biomembranes. Phosphatidylglycerols and cardiolipins are not only the main components of bacterial membranes but also of crucial importance in mitochondrial and thylakoid membranes in eukaryotic cells. In our investigations we applied five compounds of the bisphenol class most commonly detected in the environment. To characterize the bisphenols-model membrane interactions we applied multiple mutually independent methods of physical chemistry; namely: the Langmuir monolayer technique, surface potential measurements, Brewster angle microscopy for the visualization of the monolayers' texture and grazing incidence X-ray diffraction for the discussion of the phospholipids packing within the monolayers. Our studies indicated that all the investigated bisphenols interact with the model membrane, but the strength of the interactions is dependent on the bisphenol structure and hydrophobicity and the fluidity of the model membranes. We proved that bisphenol S often treated as the least toxic BPA analog can also be incorporated to the model membranes changing their structure and fluidity.
Wu, Gang
2016-08-01
The nuclear quadrupole transverse relaxation process of half-integer spins in liquid samples is known to exhibit multi-exponential behaviors. Within the framework of Redfield's relaxation theory, exact analytical expressions for describing such a process exist only for spin-3/2 nuclei. As a result, analyses of nuclear quadrupole transverse relaxation data for half-integer quadrupolar nuclei with spin >3/2 must rely on numerical diagonalization of the Redfield relaxation matrix over the entire motional range. In this work we propose an approximate analytical expression that can be used to analyze nuclear quadrupole transverse relaxation data of any half-integer spin in liquids over the entire motional range. The proposed equation yields results that are in excellent agreement with the exact numerical calculations. PMID:27343483
NEWTONP - CUMULATIVE BINOMIAL PROGRAMS
NASA Technical Reports Server (NTRS)
Bowerman, P. N.
1994-01-01
The cumulative binomial program, NEWTONP, is one of a set of three programs which calculate cumulative binomial probability distributions for arbitrary inputs. The three programs, NEWTONP, CUMBIN (NPO-17555), and CROSSER (NPO-17557), can be used independently of one another. NEWTONP can be used by statisticians and users of statistical procedures, test planners, designers, and numerical analysts. The program has been used for reliability/availability calculations. NEWTONP calculates the probably p required to yield a given system reliability V for a k-out-of-n system. It can also be used to determine the Clopper-Pearson confidence limits (either one-sided or two-sided) for the parameter p of a Bernoulli distribution. NEWTONP can determine Bayesian probability limits for a proportion (if the beta prior has positive integer parameters). It can determine the percentiles of incomplete beta distributions with positive integer parameters. It can also determine the percentiles of F distributions and the midian plotting positions in probability plotting. NEWTONP is designed to work well with all integer values 0 < k <= n. To run the program, the user simply runs the executable version and inputs the information requested by the program. NEWTONP is not designed to weed out incorrect inputs, so the user must take care to make sure the inputs are correct. Once all input has been entered, the program calculates and lists the result. It also lists the number of iterations of Newton's method required to calculate the answer within the given error. The NEWTONP program is written in C. It was developed on an IBM AT with a numeric co-processor using Microsoft C 5.0. Because the source code is written using standard C structures and functions, it should compile correctly with most C compilers. The program format is interactive. It has been implemented under DOS 3.2 and has a memory requirement of 26K. NEWTONP was developed in 1988.
Optimized non-integer order phase mask to extend the depth of field of an imaging system
NASA Astrophysics Data System (ADS)
Liu, Jiang; Miao, Erlong; Sui, Yongxin; Yang, Huaijiang
2016-09-01
Wavefront coding is an effective optical technique used to extend the depth of field for an incoherent imaging system. Through introducing an optimized phase mask to the pupil plane, the modulated optical transfer function is defocus-invariant. In this paper, we proposed a new form phase mask using non-integer order and signum function to extend the depth of field. The performance of the phase mask is evaluated by comparing defocused modulation transfer function invariant and Fisher information with other phase masks. Defocused imaging simulation is also carried out. The results demonstrate the advantages of non-integer order phase mask and its effectiveness on the depth of field extension.
Skyrmions and Single Spin Flips in the Odd Integer Quantized Hall Effect
NASA Astrophysics Data System (ADS)
Schmeller, Andreas
1996-03-01
For an (ideal) two-dimensional electron system in an odd integer quantized Hall state, the energy Δ needed to excite a quasiparticle pair is the sum of the Zeeman energy Sgμ_BB_tot (S is the number of flipped spins) and the many body contribution Δ_ex, where Δ_ex depends only on the perpendicular magnetic field component B_⊥. If the sample is tilted with respect to the field B_tot and B_⊥ is kept constant, the rate of change of Δ with B_tot gives S. We measure the energy gap Δ by thermally-activated magneto-transport experiments in tilted magnetic fields. We find: 1. At ν=1, where the ground state is fully spin polarized with only one spin level occupied, the lowest lying charged excitations have S >> 1. This reflects the excitation of quasiparticle pairs, with spins of up to 7/2 per particle, a value that is in good agreement with recent results of Knight shift experiments [1]. 2. In contrast we observe only single spin flips (S=1) at the higher odd integer filling factors ν=3 and 5. These results lend support to recent suggestions[2] that Skyrmions, which are topological distortions of the spin field that involve large spin values, form the lowest-lying charged excitations in the fully-polarized ν =1 quantum Hall fluid, but are energetically unfavorable with respect to single spin flips at the higher odd-integer filling factors. This work was done in collaboration with J.P. Eisenstein, L.N. Pfeiffer and K.W. West. 1: S.E. Barrett, G. Dabbagh, L.N. Pfeiffer, K.W. West, and Z. Tycko, Phys. Rev. Lett. 74, 5112 (1995). 2: S.L. Sondhi et al. Phys. Rev. B47, 16419 (1993). J. K. Jain and X. G. Wu, Phys. Rev. B49, 5085 (1994). X.-G. Wu and S.L. Sondhi, preprint (1995).
Huang, Weiwei; Hu, Tingxing; Chen, Hong; Wang, Qian; Hu, Hongling; Tu, Lihua; Jing, Liao
2013-09-01
A pot experiment was performed to study the impact of decomposing Cinnamomum septentrionale leaf litter on the growth of Eucalyptus grandis saplings. The experimental design scheme was 0 (CK), 40 (A1), 80 (A2) and 120 g pot(-1) (A3) of E. grandis leaves, and changes in the volatile oil chemical composition during litter decomposition were assessed in the present study. The results showed that C. septentrionale leaf litter inhibited the growth of E. grandis saplings, as determined by the height, basal diameter and chlorophyll content, after 69 d (T1). Five months after transplantation (T2), the height growth rate of the E. grandis saplings increased and then gradually reduced (A1: 40 g pot(-1) > A2: 80 g pot(-1) > A3: 120 g pot(-1) > CK: 0 g pot(-1)). After eleven months (T3), the variations in the height and basal diameter were the same as observed at T2, and the inhibition on leaf, branch, root and stem biomass increased with increasing leaf litter content. Gas chromatography-mass spectrometry (GC-MS) was used to identify the volatile compound composition. The results indicated that the C. septentrionale original leaf litter (S1) contained thirty-one volatile compounds, but the treated leaf litter S2 (which was mixed with soil for eleven months to simultaneously plant E. grandis saplings) only possessed fourteen volatile compounds, releasing many secondary metabolites in the soil during decomposition. Most of the volatile compounds were alcohols, monoterpenoids, sesquiterpenes, alkanes, alkene, esters and ketones. Most of the allelochemicals of C. septentrionale might be released during the initial decomposing process, inhibiting the growth of other plants, whereas some nutrients might be released later, promoting the height growth of plants. In conclusion, decomposing C. septentrionale leaf litter release of many allelochemicals in the soil that significantly inhibit the growth of E. grandis.
Losdat, Sylvain; Arcese, Peter; Reid, Jane M
2015-09-01
1. Extra-pair reproductive success (EPRS) is a key component of male fitness in socially monogamous systems and could cause selection on female extra-pair reproduction if extra-pair offspring (EPO) inherit high value for EPRS from their successful extra-pair fathers. However, EPRS is itself a composite trait that can be fully decomposed into subcomponents of variation, each of which can be further decomposed into genetic and environmental variances. However, such decompositions have not been implemented in wild populations, impeding evolutionary inference. 2. We first show that EPRS can be decomposed into the product of three life-history subcomponents: the number of broods available to a focal male to sire EPO, the male's probability of siring an EPO in an available brood and the number of offspring in available broods. This decomposition of EPRS facilitates estimation from field data because all subcomponents can be quantified from paternity data without need to quantify extra-pair matings. Our decomposition also highlights that the number of available broods, and hence population structure and demography, might contribute substantially to variance in male EPRS and fitness. 3. We then used 20 years of complete genetic paternity and pedigree data from wild song sparrows (Melospiza melodia) to partition variance in each of the three subcomponents of EPRS, and thereby estimate their additive genetic variance and heritability conditioned on effects of male coefficient of inbreeding, age and social status. 4. All three subcomponents of EPRS showed some degree of within-male repeatability, reflecting combined permanent environmental and genetic effects. Number of available broods and offspring per brood showed low additive genetic variances. The estimated additive genetic variance in extra-pair siring probability was larger, although the 95% credible interval still converged towards zero. Siring probability also showed inbreeding depression and increased with male age
Are Bulges and Disks Real? Decomposing Spectral Data Cubes Into Their Astrophysical Components
NASA Astrophysics Data System (ADS)
Merrifield, Michael; Tabor, Martha; Aragon-Salamanca, Alfonso; Cappellari, Michele; Johnston, Evelyn
2016-01-01
Decomposing galaxies photometrically into bulge and disk components is now a well-established technique, but it remains unclear how distinct and real these components are, and how they relate to each other. To address these questions, we have been developing novel techniques to extract the various structural components from integral field unit (IFU) spectral observations of galaxies, in order to study simultaneously their spectral and spatial properties.As a first approach, by spatially decomposing each wavelength in a spectral data cube, we can discover how much light comes from the separate components as a function of wavelength, and hence derive unprecedentedly high quality spectra of bulge and disk for detailed analysis of their stellar populations.In addition, we have decomposed spectral data cubes by fitting the spectrum at each location with the sum of two components, with the spectral properties left entirely free to fit both kinematic and stellar population properties, subject only to the constraint that the relative flux contributions match those of a conventional bulge-disk decomposition.Initial results applied to MaNGA and other IFU surveys show the power of these techniques when applied to such high quality data. The first method allows us to understand the formation sequence of bulges and disks, with, for example, bulges showing the younger stellar populations in S0 galaxies, implying that this was where the last gasp of star formation occurred. The second technique reveals subtle population gradients within individual components, but also confirms that the decomposition into separate components is a credible procedure, as the resulting bulges and disks have entirely plausible kinematic properties that are in no way imposed by the decomposition.Although our initial application of these decomposition techniques has been to studying bulges and disks in S0 galaxies, the methods have much wider application to the spectral data cubes that MaNGA and other
Huang, Weiwei; Hu, Tingxing; Chen, Hong; Wang, Qian; Hu, Hongling; Tu, Lihua; Jing, Liao
2013-09-01
A pot experiment was performed to study the impact of decomposing Cinnamomum septentrionale leaf litter on the growth of Eucalyptus grandis saplings. The experimental design scheme was 0 (CK), 40 (A1), 80 (A2) and 120 g pot(-1) (A3) of E. grandis leaves, and changes in the volatile oil chemical composition during litter decomposition were assessed in the present study. The results showed that C. septentrionale leaf litter inhibited the growth of E. grandis saplings, as determined by the height, basal diameter and chlorophyll content, after 69 d (T1). Five months after transplantation (T2), the height growth rate of the E. grandis saplings increased and then gradually reduced (A1: 40 g pot(-1) > A2: 80 g pot(-1) > A3: 120 g pot(-1) > CK: 0 g pot(-1)). After eleven months (T3), the variations in the height and basal diameter were the same as observed at T2, and the inhibition on leaf, branch, root and stem biomass increased with increasing leaf litter content. Gas chromatography-mass spectrometry (GC-MS) was used to identify the volatile compound composition. The results indicated that the C. septentrionale original leaf litter (S1) contained thirty-one volatile compounds, but the treated leaf litter S2 (which was mixed with soil for eleven months to simultaneously plant E. grandis saplings) only possessed fourteen volatile compounds, releasing many secondary metabolites in the soil during decomposition. Most of the volatile compounds were alcohols, monoterpenoids, sesquiterpenes, alkanes, alkene, esters and ketones. Most of the allelochemicals of C. septentrionale might be released during the initial decomposing process, inhibiting the growth of other plants, whereas some nutrients might be released later, promoting the height growth of plants. In conclusion, decomposing C. septentrionale leaf litter release of many allelochemicals in the soil that significantly inhibit the growth of E. grandis. PMID:23835358
Fanin, Nicolas; Fromin, Nathalie; Bertrand, Isabelle
2016-04-01
In addition to the effect of litter quality (LQ) on decomposition, increasing evidence is demonstrating that carbon mineralization can be influenced by the past resource history, mainly through following two processes: (1) decomposer communities from recalcitrant litter environments may have a wider functional ability to decompose a wide range of litter species than those originating from richer environments, i.e., the functional breadth (FB) hypothesis; and/or (2) decomposer communities may be specialized towards the litter they most frequently encounter, i.e., the home-field advantage (HFA) hypothesis. Nevertheless, the functional dissimilarities among contrasting microbial communities, which are generated by the FB and the HFA, have rarely been simultaneously quantified in the same experiment, and their relative contributions over time have never been assessed. To test these hypotheses, we conducted a reciprocal transplant decomposition experiment under controlled conditions using litter and soil originating from four ecosystems along a land-use gradient (forest, plantation, grassland, and cropland) and one additional treatment using 13C-labelled flax litter allowing us to assess the priming effect (PE) in each ecosystem. We found substantial effects of LQ on carbon mineralization (more than two-thirds of the explained variance), whereas the contribution of the soil type was fairly low (less than one-tenth), suggesting that the contrasting soil microbial communities play only a minor role in regulating decomposition rates. Although the results on PE showed that we overestimated litter-derived CO2 fluxes, litter-microbe interactions contributed significantly to the unexplained variance observed in carbon mineralization models. The magnitudes of FB and HFA were relatively similar, but the directions of these mechanisms were sometimes opposite depending on the litter and soil types. FB and HFA estimates calculated on parietal sugar mass loss were positively
Half-integer flux quantization in a superconducting loop with a ferromagnetic π-junction
NASA Astrophysics Data System (ADS)
Bauer, A.; Bentner, J.; Aprili, M.; Della Rocca, M.; Reinwald, M.; Wegscheider, W.; Strunk, C.
2006-09-01
Superconducting loops containing a π-junction are predicted to show a spontaneous magnetic moment in zero external magnetic field. In order to confirm this longstanding prediction experimentally we performed magnetization measurements on individual mesoscopic superconducting niobium loops with a ferromagnetic (PdNi) π-junction. The loops are prepared on top of the active area of a micro Hall-sensor based on high mobility GaAs/AlGaAs heterostructures. We observe switching of the loop between different magnetization states at very low magnetic fields, which is asymmetric for positive and negative sweep direction. This is evidence for a spontaneous current induced by the intrinsic phase shift of the π-junction. In addition, the presence of the spontaneous current at zero applied field is directly revealed by an increase of the magnetic moment with decreasing temperature, which results in half integer flux quantization in the loop at low temperatures.
NASA Astrophysics Data System (ADS)
Ganeshan, Sriram; Kechedzhi, K.; Das Sarma, S.
2014-07-01
One-dimensional tight binding models such as the Aubry-André-Harper (AAH) model (with an on-site cosine potential) and the integrable Maryland model (with an on-site tangent potential) have been the subject of extensive theoretical research in localization studies. AAH can be directly mapped onto the two-dimensional (2D) Hofstadter model which manifests the integer quantum Hall topology on a lattice. However, such a connection needs to be made for the Maryland model (MM). Here we describe a generalized model that contains AAH and MM as the limiting cases with the MM lying precisely at a topological quantum phase transition (TQPT) point. A remarkable feature of this critical point is that the one-dimensional MM retains well defined energy gaps whereas the equivalent 2D model becomes gapless, signifying the 2D nature of the TQPT.
Subjective evaluations of integer cosine transform compressed Galileo solid state imagery
NASA Astrophysics Data System (ADS)
Haines, Richard F.; Gold, Yaron; Grant, Terry; Chuang, Sherry
1994-07-01
This paper describes a study conducted for the Jet Propulsion Laboratory, Pasadena, California, using 15 evaluators from 12 institutions involved in the Galileo Solid State Imaging (SSI) experiment. The objective of the study was to determine the impact of integer cosine transform (ICT) compression using specially formulated quantization (q) tables and compression ratios on acceptability of the 800 x 800 x 8 monochromatic astronomical images as evaluated visually by Galileo SSI mission scientists. Fourteen different images in seven image groups were evaluated. Each evaluator viewed two versions of the same image side by side on a high-resolution monitor; each was compressed using a different q level. First the evaluators selected the image with the highest overall quality to support them in their visual evaluations of image content. Next they rated each image using a scale from one to five indicating its judged degree of usefulness. Up to four preselected types of images with and without noise were presented to each evaluator.
High-resolution multiple quantum MAS NMR spectroscopy of half-integer quadrupolar nuclei
NASA Astrophysics Data System (ADS)
Wu, Gang; Rovnyank, David; Sun, Boqin; Griffin, Robert G.
1996-02-01
We demonstrate the utility of a two-pulse sequence in obtaining high-resolution solid state NMR spectra of half-integer quadrupolar nuclei with magic-angle-spinning (MAS). The experiment, which utilizes multiple/single-quantum correlation, was first described in a different form by Frydman and Harwood [J. Am. Chem. Soc. 117 (1995) 5367] and yields high-resolution isotropic NMR spectra where shifts are determined by the sum of resonance offset (chemical shift) and second-order quadrupolar effects. The two-pulse sequence described here is shown to provide a higher and more uniform excitation of multiple-quantum coherence than the three-pulse sequence used previously.
A Mixed-Integer Optimization Framework for De Novo Peptide Identification
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
An efficient FPGA architecture for integer ƞth root computation
NASA Astrophysics Data System (ADS)
Rangel-Valdez, Nelson; Barron-Zambrano, Jose Hugo; Torres-Huitzil, Cesar; Torres-Jimenez, Jose
2015-10-01
In embedded computing, it is common to find applications such as signal processing, image processing, computer graphics or data compression that might benefit from hardware implementation for the computation of integer roots of order ?. However, the scientific literature lacks architectural designs that implement such operations for different values of N, using a low amount of resources. This article presents a parameterisable field programmable gate array (FPGA) architecture for an efficient Nth root calculator that uses only adders/subtractors and ? location memory elements. The architecture was tested for different values of ?, using 64-bit number representation. The results show a consumption up to 10% of the logical resources of a Xilinx XC6SLX45-CSG324C device, depending on the value of N. The hardware implementation improved the performance of its corresponding software implementations in one order of magnitude. The architecture performance varies from several thousands to seven millions of root operations per second.
Lim, S B; Kanthimathi, M S; Hashim, O H
1998-12-01
The effect of the mannose-binding champedak (Artocarpus integer) lectin-M on the cellular proliferation of murine lymphocytes was investigated in this study. Our data demonstrated that the lectin was the main mitogenic component in the crude extract of the champedak seeds. It stimulated the proliferation of murine T cells at an optimal concentration of 2.5 microg/ml in a 3 day culture. Lectin-M appeared to be a T-cell mitogen as it does not induce significant DNA synthesis when cultured with spleen cells from the nude mouse. In the absence of T cells, the lectin was incapable of inducing resting B cells to differentiate into immunoglobulin secreting plasma cells.
Subjective evaluations of integer cosine transform compressed Galileo solid state imagery
NASA Technical Reports Server (NTRS)
Haines, Richard F.; Gold, Yaron; Grant, Terry; Chuang, Sherry
1994-01-01
This paper describes a study conducted for the Jet Propulsion Laboratory, Pasadena, California, using 15 evaluators from 12 institutions involved in the Galileo Solid State Imaging (SSI) experiment. The objective of the study was to determine the impact of integer cosine transform (ICT) compression using specially formulated quantization (q) tables and compression ratios on acceptability of the 800 x 800 x 8 monochromatic astronomical images as evaluated visually by Galileo SSI mission scientists. Fourteen different images in seven image groups were evaluated. Each evaluator viewed two versions of the same image side by side on a high-resolution monitor; each was compressed using a different q level. First the evaluators selected the image with the highest overall quality to support them in their visual evaluations of image content. Next they rated each image using a scale from one to five indicating its judged degree of usefulness. Up to four preselected types of images with and without noise were presented to each evaluator.
Decomposing race and gender differences in underweight and obesity in South Africa.
Averett, Susan L; Stacey, Nicholas; Wang, Yang
2014-12-01
Using data from the National Income Dynamics Study, we document differentials in both underweight and obesity across race and gender in post-Apartheid South Africa. Using a nonlinear decomposition method, we decompose these differences across gender within race and then across race within gender. Less than one third of the differences in obesity and underweight across gender are explained by differences in covariates. In contrast, at least 70% of the obesity differences across race are explained by differences in covariates. Behavioral variables such as smoking and exercise explain the largest part of the bodyweight differentials across gender. For bodyweight differentials across race within gender, however, socioeconomic status and background variables have the largest explanatory power for obesity differentials, while background variables play the key role in explaining the underweight differentials. These results indicate that eradicating obesity and underweight differentials will require targeting policies to specific groups.
Fatal motor vehicle crashes in rural and urban areas: decomposing rates into contributing factors
Zwerling, C; Peek-Asa, C; Whitten, P; Choi, S; Sprince, N; Jones, M
2005-01-01
Objectives: Motor vehicle crash fatality rates have been consistently higher in rural areas than in urban areas. However, the explanations for these differences are less clear. In this study the decomposition method was used to explore the factors associated with increased fatal crash involvement rates in rural communities. Design: Using national databases, the fatal crash incidence density was decomposed into the product of three factors: the injury fatality rate, the crash injury rate, and the crash incidence density. Results: As expected, the fatal crash incidence density was more than two times higher in rural than in urban areas. This was driven primarily by the injury fatality rate, which was almost three times higher in rural areas. Conclusions: Further research should examine the relative roles of crash severity and the timely receipt of definitive medical care after a crash. PMID:15691985
Bacteria in decomposing wood and their interactions with wood-decay fungi.
Johnston, Sarah R; Boddy, Lynne; Weightman, Andrew J
2016-11-01
The fungal community within dead wood has received considerable study, but far less attention has been paid to bacteria in the same habitat. Bacteria have long been known to inhabit decomposing wood, but much remains underexplored about their identity and ecology. Bacteria within the dead wood environment must interact with wood-decay fungi, but again, very little is known about the form this takes; there are indications of both antagonistic and beneficial interactions within this fungal microbiome. Fungi are hypothesised to play an important role in shaping bacterial communities in wood, and conversely, bacteria may affect wood-decay fungi in a variety of ways. This minireview considers what is currently known about bacteria in wood and their interactions with fungi, and proposes possible associations based on examples from other habitats. It aims to identify key knowledge gaps and pressing questions for future research.
Schaefer, Rebecca S; Vlek, Rutger J; Desain, Peter
2011-03-01
Perceiving musical rhythms can be considered a process of attentional chunking over time, driven by accent patterns. A rhythmic structure can also be generated internally, by placing a subjective accent pattern on an isochronous stimulus train. Here, we investigate the event-related potential (ERP) signature of actual and subjective accents, thus disentangling low-level perceptual processes from the cognitive aspects of rhythm processing. The results show differences between accented and unaccented events, but also show that different types of unaccented events can be distinguished, revealing additional structure within the rhythmic pattern. This structure is further investigated by decomposing the ERP into subcomponents, using principal component analysis. In this way, the processes that are common for perceiving a pattern and self-generating it are isolated, and can be visualized for the tasks separately. The results suggest that top-down processes have a substantial role in the cerebral mechanisms of rhythm processing, independent of an externally presented stimulus.
The applications of a higher-dimensional Lie algebra and its decomposed subalgebras
Yu, Zhang; Zhang, Yufeng
2009-01-01
With the help of invertible linear transformations and the known Lie algebras, a higher-dimensional 6 × 6 matrix Lie algebra sμ(6) is constructed. It follows a type of new loop algebra is presented. By using a (2 + 1)-dimensional partial-differential equation hierarchy we obtain the integrable coupling of the (2 + 1)-dimensional KN integrable hierarchy, then its corresponding Hamiltonian structure is worked out by employing the quadratic-form identity. Furthermore, a higher-dimensional Lie algebra denoted by E, is given by decomposing the Lie algebra sμ(6), then a discrete lattice integrable coupling system is produced. A remarkable feature of the Lie algebras sμ(6) and E is used to directly construct integrable couplings. PMID:20084092
Zhang, Xi; Zhong, Yaohua; Yang, Shida; Zhang, Weixin; Xu, Meiqing; Ma, Anzhou; Zhuang, Guoqiang; Chen, Guanjun; Liu, Weifeng
2014-10-01
The development of communities of three important composting players including actinobacteria, fungi and clostridia was explored during the composting of wheat straw for mushroom production. The results revealed the presence of highly diversified actinobacteria and fungal communities during the composting process. The diversity of the fungal community, however, sharply decreased in the mature compost. Furthermore, an apparent succession of both actinobacteria and fungi with intensive changes in the composition of communities was demonstrated during composting. Notably, cellulolytic actinomycetal and fungal genera represented by Thermopolyspora, Microbispora and Humicola were highly enriched in the mature compost. Analysis of the key cellulolytic genes revealed their prevalence at different composting stages including several novel glycoside hydrolase family 48 exocellulase lineages. The community of cellulolytic microbiota also changed substantially over time. The prevalence of the diversified cellulolytic microorganisms holds the great potential of mining novel lignocellulose decomposing enzymes from this specific ecosystem.
The plant cell wall decomposing machinery underlies the functional diversity of forest fungi
Eastwood, Daniel C.; Floudas, Dimitrios; Binder, Manfred; Majcherczyk, Andrzej; Schneider, Patrick; Aerts, Andrea; Asiegbu, Fred O.; Baker, Scott E.; Barry, Kerrie; Bendiksby, Mika; Blumentritt, Melanie; Coutinho, Pedro M.; Cullen, Dan; Vries, Ronald P. de; Gathman, Allen; Goodell, Barry; Henrissat, Bernard; Ihrmark, Katarina; Kauserud, Hä; vard,; Kohler, Annegret; LaButti, Kurt; Lapidus, Alla; Lavin, José; L.; Lee, Yong-Hwan; Lindquist, Erika; Lilly, Walt; Lucas, Susan; Morin, Emmanuelle; Murat, Claude; Oguiza, José; A.; Park, Jongsun; Pisabarro, Antonio G.; Riley, Robert; Rosling, Anna; Salamov, Asaf; Schmidt, Olaf; Schmutz, Jeremy; Skrede, Inger; Stenlid, Jan; Wiebenga, Ad; Xie, Xinfeng; Kü; es, Ursula; Hibbett, David S.; Hoffmeister, Dirk; Hö; gberg, Nils; Martin, Francis; Grigoriev, Igor V.; Watkinson, Sarah C.
2011-05-01
Brown rot decay removes cellulose and hemicellulose from wood?residual lignin contributing up to 30percent of forest soil carbon?and is derived from an ancestral white rot saprotrophy in which both lignin and cellulose are decomposed. Comparative and functional genomics of the ?dry rot? fungus Serpula lacrymans, derived from forest ancestors, demonstrated that the evolution of both ectomycorrhizal biotrophy and brown rot saprotrophy were accompanied by reductions and losses in specific protein families, suggesting adaptation to an intercellular interaction with plant tissue. Transcriptome and proteome analysis also identified differences in wood decomposition in S. lacrymans relative to the brown rot Postia placenta. Furthermore, fungal nutritional mode diversification suggests that the boreal forest biome originated via genetic coevolution of above- and below-ground biota
NASA Astrophysics Data System (ADS)
Mapes, B. E.; Kelly, P.; Song, S.; Hu, I. K.; Kuang, Z.
2015-12-01
An economical 10-layer global primitive equation solver is driven by time-independent forcing terms, derived from a training process, to produce a realisting eddying basic state with a tracer q trained to act like water vapor mixing ratio. Within this basic state, linearized anomaly moist physics in the column are applied in the form of a 20x20 matrix. The control matrix was derived from the results of Kuang (2010, 2012) who fitted a linear response function from a cloud resolving model in a state of deep convecting equilibrium. By editing this matrix in physical space and eigenspace, scaling and clipping its action, and optionally adding terms for processes that do not conserve moist statice energy (radiation, surface fluxes), we can decompose and explain the model's diverse moist process coupled variability. Recitified effects of this variability on the general circulation and climate, even in strictly zero-mean centered anomaly physic cases, also are sometimes surprising.
NASA Astrophysics Data System (ADS)
Ponyavin, Valery; Chen, Yitung; Hechanova, Anthony E.; Wilson, Merrill
2008-09-01
The present study addresses fluid flow and heat transfer in a high temperature compact heat exchanger which will be used as a chemical decomposer in a hydrogen production plant. The heat exchanger is manufactured using fused ceramic layers that allow creation of channels with dimensions below 1 mm. The main purpose of this study is to increase the thermal performance of the heat exchanger, which can help to increase the sulfuric acid decomposition rate. Effects of various channel geometries of the heat exchanger on the pressure drop are studied as well. A three-dimensional computational model is developed for the investigation of fluid flow and heat transfer in the heat exchanger. Several different geometries of the heat exchanger channels, such as straight channels, ribbed ground channels, hexagonal channels, and diamond-shaped channels are examined. Based on the results, methods on how to improve the design of the heat exchanger are recommended.
Long-term stabilization of organic solar cells using hydroperoxide decomposers as additives
NASA Astrophysics Data System (ADS)
Turkovic, Vida; Engmann, Sebastian; Tsierkezos, Nikos; Hoppe, Harald; Madsen, Morten; Rubahn, Horst-Günter; Ritter, Uwe; Gobsch, Gerhard
2016-03-01
Stability of organic solar cells (OPV) remains a big problem on the way to their commercialization. Different approaches are being investigated: development of intrinsically more photochemically stable materials, optimization of encapsulation, and implementation of getter and UV blocking layers. In this study, we investigate stabilization of OPV devices using hydroperoxide decomposers as stabilizing additives. A set of five commercially available additives of organophosphorus, organosulfur, Ni chelate, and blocked thiol type are compared, ternary blended into the active layer, under exposure to aging under ISOS-3 degradation conditions. Improvements in long-term performance of OPV devices were observed upon stabilization with Advapak NEO-1120, lifetime was prolonged by a factor of 1.7, and accumulated power generation increased by a factor of 1.4. The stabilizing mechanisms are discussed using spectroscopic and microscopic measurements.
Phase stability of decomposed Ni-Al alloys under ion irradiation
Schmitz, G.; Ewert, J. C.; Harbsmeier, F.; Uhrmacher, M.; Haider, F.
2001-06-01
The disordering of a decomposed Ni-12at.%-Al alloy under irradiation with 300-keV Ni{sup +} ions is studied in direct comparison to homogeneous Ni{sub 3}Al at various temperatures. For that, the degree of long-range order is quantitatively determined by electron diffractometry. Heterogeneous alloys disorder significantly faster than the homogeneous intermetallic. In addition, their disordering rate depends on the precipitate size of the microstructure. At 823 K a steady state with an intermediate degree of order is reached. The experimental results are compared with model calculation based on a Cahn-Hilliard-type continuum model. At higher temperatures the model yields a correct description of the experiments. However, discrepancies at room temperature suggest a direct coupling of local composition and degree of order during the collision cascade. This interpretation is further supported by Monte Carlo simulations of overlapping cascade events.
Valle, Denis; Baiser, Benjamin; Woodall, Christopher W; Chazdon, Robin
2014-12-01
We propose a novel multivariate method to analyse biodiversity data based on the Latent Dirichlet Allocation (LDA) model. LDA, a probabilistic model, reduces assemblages to sets of distinct component communities. It produces easily interpretable results, can represent abrupt and gradual changes in composition, accommodates missing data and allows for coherent estimates of uncertainty. We illustrate our method using tree data for the eastern United States and from a tropical successional chronosequence. The model is able to detect pervasive declines in the oak community in Minnesota and Indiana, potentially due to fire suppression, increased growing season precipitation and herbivory. The chronosequence analysis is able to delineate clear successional trends in species composition, while also revealing that site-specific factors significantly impact these successional trajectories. The proposed method provides a means to decompose and track the dynamics of species assemblages along temporal and spatial gradients, including effects of global change and forest disturbances.
A spectral analysis of the domain decomposed Monte Carlo method for linear systems
Slattery, S. R.; Wilson, P. P. H.; Evans, T. M.
2013-07-01
The domain decomposed behavior of the adjoint Neumann-Ulam Monte Carlo method for solving linear systems is analyzed using the spectral properties of the linear operator. Relationships for the average length of the adjoint random walks, a measure of convergence speed and serial performance, are made with respect to the eigenvalues of the linear operator. In addition, relationships for the effective optical thickness of a domain in the decomposition are presented based on the spectral analysis and diffusion theory. Using the effective optical thickness, the Wigner rational approximation and the mean chord approximation are applied to estimate the leakage fraction of stochastic histories from a domain in the decomposition as a measure of parallel performance and potential communication costs. The one-speed, two-dimensional neutron diffusion equation is used as a model problem to test the models for symmetric operators. In general, the derived approximations show good agreement with measured computational results. (authors)
Atomic iodine production in a gas flow by decomposing methyl iodide in a dc glow discharge
Mikheyev, P A; Shepelenko, A A; Voronov, A I; Kupryaev, Nikolai V
2002-01-31
The production of atomic iodine for an oxygen - iodine laser is studied by decomposing methyl iodide in a dc glow discharge in a vortex gas flow. The concentration of iodine atoms in discharge products was measured from the atomic iodine absorption of the radiation of a single-frequency tunable diode laser at a wavelength of 1.315 {mu}m. Atomic iodine concentrations sufficient for the operation of an oxygen - iodine laser were obtained. The concentration of atomic iodine amounted to 3.6 x 10{sup 15} cm{sup -3} for a pressure of the carrying argon gas of 15 Torr. The discharge stabilisation by a vortex gas flow allowed the glow discharge to be sustained in a strongly electronegative halogen-containing gas mixture for pressures up to 20 Torr. (active media)
The applications of a higher-dimensional Lie algebra and its decomposed subalgebras.
Yu, Zhang; Zhang, Yufeng
2009-01-15
With the help of invertible linear transformations and the known Lie algebras, a higher-dimensional 6 x 6 matrix Lie algebra smu(6) is constructed. It follows a type of new loop algebra is presented. By using a (2 + 1)-dimensional partial-differential equation hierarchy we obtain the integrable coupling of the (2 + 1)-dimensional KN integrable hierarchy, then its corresponding Hamiltonian structure is worked out by employing the quadratic-form identity. Furthermore, a higher-dimensional Lie algebra denoted by E, is given by decomposing the Lie algebra smu(6), then a discrete lattice integrable coupling system is produced. A remarkable feature of the Lie algebras smu(6) and E is used to directly construct integrable couplings.
‘Willpower’ over the life span: decomposing self-regulation
Ayduk, Ozlem; Berman, Marc G.; Casey, B. J.; Gotlib, Ian H.; Jonides, John; Kross, Ethan; Teslovich, Theresa; Wilson, Nicole L.; Zayas, Vivian
2011-01-01
In the 1960s, Mischel and colleagues developed a simple ‘marshmallow test’ to measure preschoolers’ ability to delay gratification. In numerous follow-up studies over 40 years, this ‘test’ proved to have surprisingly significant predictive validity for consequential social, cognitive and mental health outcomes over the life course. In this article, we review key findings from the longitudinal work and from earlier delay-of-gratification experiments examining the cognitive appraisal and attention control strategies that underlie this ability. Further, we outline a set of hypotheses that emerge from the intersection of these findings with research on ‘cognitive control’ mechanisms and their neural bases. We discuss implications of these hypotheses for decomposing the phenomena of ‘willpower’ and the lifelong individual differences in self-regulatory ability that were identified in the earlier research and that are currently being pursued. PMID:20855294
Bacteria in decomposing wood and their interactions with wood-decay fungi.
Johnston, Sarah R; Boddy, Lynne; Weightman, Andrew J
2016-11-01
The fungal community within dead wood has received considerable study, but far less attention has been paid to bacteria in the same habitat. Bacteria have long been known to inhabit decomposing wood, but much remains underexplored about their identity and ecology. Bacteria within the dead wood environment must interact with wood-decay fungi, but again, very little is known about the form this takes; there are indications of both antagonistic and beneficial interactions within this fungal microbiome. Fungi are hypothesised to play an important role in shaping bacterial communities in wood, and conversely, bacteria may affect wood-decay fungi in a variety of ways. This minireview considers what is currently known about bacteria in wood and their interactions with fungi, and proposes possible associations based on examples from other habitats. It aims to identify key knowledge gaps and pressing questions for future research. PMID:27559028
Macroscopic, microscopic, and chemical assessment of gunshot lesions on decomposed pig skin.
Gibelli, Daniele; Brandone, Alberto; Andreola, Salvatore; Porta, Davide; Giudici, Elena; Grandi, Marco Aurelio; Cattaneo, Cristina
2010-07-01
Very little literature exists on gunshot wounds on decomposed material. In this study, seven pig heads underwent a shooting test. Entrance wounds from the first head underwent neutron activation analysis (NAA) and histological testing immediately after the firing test; the other six heads were exposed to two different environments (open air and soil) and analyzed by radiochemical and histological tests every 15 days. Gunshot wounds in air maintained their morphological characteristics, and those in soil showed severe alteration after 5 weeks. Microscopic testing verified positive results for lead in all gunshot wounds in open air, whereas in most of those in soil lead could not be detected. Radiochemical analysis performed by NAA yielded for all gunshot wounds but one antimony quantities in the range of 0.07-13.89 microg. In conclusion, it may be possible to detect residues of antimony even in degraded tissues.
May Ingestion of Leachate from Decomposed Corpses Cause Appendicitis? A Case Report
Domingues-Ferreira, Maurício; Saddi-Rosa, Pedro; dos Santos, André Luis
2011-01-01
The general consensus is that appendicitis is basically provoked by fecaliths or lymphoid hyperplasic obstruction. Several studies based on histological diagnosis have not confirmed this hypothesis. On the contrary, obstruction has been proved in only a minority of cases. Diverse infections by parasites, bacteria, fungus, and noninfective agents have been associated with appendicitis in the medical literature. We describe a firefighter, who ingested a small quantity of leachate from decomposing corpses while working and developed enteritis a few hours later, which lasted several days and evolved to appendicitis. This case raises the possibility that the high quantity of bacteria concentration present in the leachate could have provoked enteritis and the subsequent appendicitis due to a direct effect of the bacteria on the appendix. PMID:21541232
On the use of lossless integer wavelet transforms in medical image segmentation
NASA Astrophysics Data System (ADS)
Nagaraj, Nithin; Mallya, Yogish
2005-04-01
Recent trends in medical image processing involve computationally intensive processing techniques on large data sets, especially for 3D applications such as segmentation, registration, volume rendering etc. Multi-resolution image processing techniques have been used in order to speed-up these methods. However, all well-known techniques currently used in multi-resolution medical image processing rely on using Gaussain-based or other equivalent floating point representations that are lossy and irreversible. In this paper, we study the use of Integer Wavelet Transforms (IWT) to address the issue of lossless representation and reversible reconstruction for such medical image processing applications while still retaining all the benefits which floating-point transforms offer such as high speed and efficient memory usage. In particular, we consider three low-complexity reversible wavelet transforms namely the - Lazy-wavelet, the Haar wavelet or (1,1) and the S+P transform as against the Gaussian filter for multi-resolution speed-up of an automatic bone removal algorithm for abdomen CT Angiography. Perfect-reconstruction integer wavelet filters have the ability to perfectly recover the original data set at any step in the application. An additional advantage with the reversible wavelet representation is that it is suitable for lossless compression for purposes of storage, archiving and fast retrieval. Given the fact that even a slight loss of information in medical image processing can be detrimental to diagnostic accuracy, IWTs seem to be the ideal choice for multi-resolution based medical image segmentation algorithms. These could also be useful for other medical image processing methods.
Climatic effects on decomposing litter and substrate chemistry along climatological gradients.
NASA Astrophysics Data System (ADS)
Berg, B.
2009-04-01
Climatic effects on decomposing litter and substrate chemistry along climatological gradients. B. Berg, Dipartimento Biologia Strutturale e Funzionale, Complesso Universitario, Monte San Angelo, via Cintia, I-80126 Napoli, Italy and Department of Forest Ecology, P.O. Box 27, University of Helsinki, FIN-00014, Helsinki, Finland. Studies of several processes, using climatic gradients do provide new information as compared with studies at e.g. a single site. Decomposition of plant litter in such gradients give response in decomposition rates to natural climate conditions. Thus Scots pine needle litter incubated in a climate gradient with annual average temperature (AVGT) ranging from -0.5 to 6.8oC had a highly significant increase in initial mass-loss rate with R2 = 0.591 (p<0.001) and a 5o increase in temperature doubled the mass-loss rate. As a contrast - needle litter of Norway spruce incubated in the same transect had no significant response to climate and for initial litter a 5o increase increased mass-loss rate c. 6%. For more decomposed Scots pine litter we could see that the effect of temperature on mass-loss rate gradually decreased until it disappeared. Long-term decomposition studies revealed differences in litter decomposition patterns along a gradient, even for the same type of litter. This could be followed by using an asymptotic function that gave, (i) a measure a maximum level of decomposition, (ii) the initial decomposition rate. Over a gradient the calculated maximum level of decomposition decreased with increasing AVGT. Other gradient studies revealed an effect of AVGT on litter chemical composition. Pine needle litter from stands under different climate conditions had nutrient concentrations related to AVGT. Thus N, P, K, and S were positively related to AVGT and Mn negatively, all of them significantly. This information may be used to explain the changing pattern in decomposition over the gradient.
Wardle, David A; Jonsson, Micael; Kalela-Brundin, Maarit; Lagerström, Anna; Bardgett, Richard D; Yeates, Gregor W; Nilsson, Marie-Charlotte
2012-03-01
Despite the likely importance of inter-year dynamics of plant production and consumer biota for driving community- and ecosystem-level processes, very few studies have explored how and why these dynamics vary across contrasting ecosystems. We utilized a well-characterized system of 30 lake islands in the boreal forest zone of northern Sweden across which soil fertility and productivity vary considerably, with larger islands being more fertile and productive than smaller ones. In this system we assessed the inter-year dynamics of several measures of plant production and the soil microbial community (primary consumers in the decomposer food web) for each of nine years, and soil microfaunal groups (secondary and tertiary consumers) for each of six of those years. We found that, for measures of plant production and each of the three consumer trophic levels, inter-year dynamics were strongly affected by island size. Further, many variables were strongly affected by island size (and thus bottom-up regulation by soil fertility and resources) in some years, but not in other years, most likely due to inter-year variation in climatic conditions. For each of the plant and microbial variables for which we had nine years of data, we also determined the inter-year coefficient of variation (CV), an inverse measure of stability. We found that CVs of some measures of plant productivity were greater on large islands, whereas those of other measures were greater on smaller islands; CVs of microbial variables were unresponsive to island size. We also found that the effects of island size on the temporal dynamics of some variables were related to inter-year variability of macroclimatic variables. As such, our results show that the inter-year dynamics of both plant productivity and decomposer biota across each of three trophic levels, as well as the inter-year stability of plant productivity, differ greatly across contrasting ecosystems, with potentially important but largely overlooked
NASA Astrophysics Data System (ADS)
Schaedel, C.; Ernakovich, J. G.; Harden, J. W.; Natali, S.; Richter, A.; Schuur, E.; Treat, C. C.
2015-12-01
Soil organic matter decomposition depends on physical, chemical, and biological factors, such as the amount and quality of the organic matter stored, abiotic conditions (such as soil temperature and moisture), microbial community dynamics, and physical protection by soil minerals. Soils store immense amounts of carbon with 1330-1580 Pg of carbon in the permafrost region alone. Increasing temperatures in the Arctic will thaw large amounts of previously frozen organic carbon making it available for decomposition. The rate at which carbon is being released from permafrost soils is crucial for understanding future changes in permafrost carbon storage and carbon flux to the atmosphere. The potential magnitude and form of carbon release (carbon dioxide or methane) from permafrost can be investigated using soil incubation studies. Over the past 20 years, many incubation studies have been published with soils from the permafrost zone and three recent syntheses have summarized current findings from aerobic and anaerobic incubation studies. However, the breadth of the incubation synthesis projects was hampered by incomplete meta-data and the use of different methods. Here, we provide recommendations to improve and standardize future soil incubation studies (which are not limited to permafrost soils) to make individual studies useful for inclusion in syntheses and meta-analyses, which helps to broaden their impact on our understanding of organic matter cycling. Additionally, we identify gaps in the understanding of permafrost carbon decomposability, that, when coupled with emerging knowledge from field observations and experiments, can be implemented in future studies to gain a better overview of the overall decomposability of permafrost carbon.
NASA Astrophysics Data System (ADS)
Song, Linye; Duan, Wansuo; Li, Yun; Mao, Jiangyu
2015-04-01
A time-scale decomposed threshold regression (TSDTR) downscaling approach to forecasting South China early summer rainfall (SCESR) is described by using long-term observed station rainfall data and the National Oceanic and Atmospheric Administration Extended Reconstructed sea surface temperature (SST) data. It makes use of two distinct regression downscaling models corresponding to the interannual and interdecadal rainfall variability of SCESR. The two models were developed based on the partial least square (PLS) regression technique linking SCESR to SST modes in preceding months on both interannual and interdecadal timescales. Specially, using the datasets in the calibration period 1915-1984, the variability of SCESR and SST were decomposed into interannual and interdecadal components. On the interannual timescale, a threshold PLS regression model was fitted to interannual components of SCESR and March SST patterns by taking account of the modulation of negative and positive phases of the Pacific Decadal Oscillation (PDO). On the interdecadal timescale, a standard PLS regression model was fitted to the relationship between SCESR and preceding November SST patterns. The total rainfall prediction was obtained by the sum of the outputs from both interannual and interdecadal models. Results show that the TSDTR downscaling approach achieved a reasonable skill to predict the observed rainfall in the validation period 1985-2006, compared to other simpler approaches. This study suggests that the TSDTR approach considering different interannual SCESR-SST relationships under the modulation of PDO phases, as well as the interdecadal variability of SCESR associated with SST patterns may provide a new perspective to improve the climate predictions.
Wardle, David A; Jonsson, Micael; Kalela-Brundin, Maarit; Lagerström, Anna; Bardgett, Richard D; Yeates, Gregor W; Nilsson, Marie-Charlotte
2012-03-01
Despite the likely importance of inter-year dynamics of plant production and consumer biota for driving community- and ecosystem-level processes, very few studies have explored how and why these dynamics vary across contrasting ecosystems. We utilized a well-characterized system of 30 lake islands in the boreal forest zone of northern Sweden across which soil fertility and productivity vary considerably, with larger islands being more fertile and productive than smaller ones. In this system we assessed the inter-year dynamics of several measures of plant production and the soil microbial community (primary consumers in the decomposer food web) for each of nine years, and soil microfaunal groups (secondary and tertiary consumers) for each of six of those years. We found that, for measures of plant production and each of the three consumer trophic levels, inter-year dynamics were strongly affected by island size. Further, many variables were strongly affected by island size (and thus bottom-up regulation by soil fertility and resources) in some years, but not in other years, most likely due to inter-year variation in climatic conditions. For each of the plant and microbial variables for which we had nine years of data, we also determined the inter-year coefficient of variation (CV), an inverse measure of stability. We found that CVs of some measures of plant productivity were greater on large islands, whereas those of other measures were greater on smaller islands; CVs of microbial variables were unresponsive to island size. We also found that the effects of island size on the temporal dynamics of some variables were related to inter-year variability of macroclimatic variables. As such, our results show that the inter-year dynamics of both plant productivity and decomposer biota across each of three trophic levels, as well as the inter-year stability of plant productivity, differ greatly across contrasting ecosystems, with potentially important but largely overlooked
Denoising, deconvolving, and decomposing photon observations. Derivation of the D3PO algorithm
NASA Astrophysics Data System (ADS)
Selig, Marco; Enßlin, Torsten A.
2015-02-01
The analysis of astronomical images is a non-trivial task. The D3PO algorithm addresses the inference problem of denoising, deconvolving, and decomposing photon observations. Its primary goal is the simultaneous but individual reconstruction of the diffuse and point-like photon flux given a single photon count image, where the fluxes are superimposed. In order to discriminate between these morphologically different signal components, a probabilistic algorithm is derived in the language of information field theory based on a hierarchical Bayesian parameter model. The signal inference exploits prior information on the spatial correlation structure of the diffuse component and the brightness distribution of the spatially uncorrelated point-like sources. A maximum a posteriori solution and a solution minimizing the Gibbs free energy of the inference problem using variational Bayesian methods are discussed. Since the derivation of the solution is not dependent on the underlying position space, the implementation of the D3PO algorithm uses the nifty package to ensure applicability to various spatial grids and at any resolution. The fidelity of the algorithm is validated by the analysis of simulated data, including a realistic high energy photon count image showing a 32 × 32 arcmin2 observation with a spatial resolution of 0.1 arcmin. In all tests the D3PO algorithm successfully denoised, deconvolved, and decomposed the data into a diffuse and a point-like signal estimate for the respective photon flux components. A copy of the code is available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/574/A74
ERIC Educational Resources Information Center
Gauthier, N.
2008-01-01
A general method is presented for evaluating the sums of "m"th powers of the integers that can, and that cannot, be represented in the two-element Frobenius problem. Generating functions are introduced and used for that purpose. Explicit formulas for the desired sums are obtained and specific examples are discussed.
ERIC Educational Resources Information Center
Stoessiger, Rex
2013-01-01
A critical numeracy examination of Benford's Law suggests that our understanding of the integers is faulty. We think of them as equally likely to turn up as the first digit of a random real world number. For many real world data sets this is not true. In many cases, ranging from eBay auction prices to six digit numbers in Google to the…
On Vieta's Formulas and the Determination of a Set of Positive Integers by Their Sum and Product
ERIC Educational Resources Information Center
Valahas, Theodoros; Boukas, Andreas
2011-01-01
In Years 9 and 10 of secondary schooling students are typically introduced to quadratic expressions and functions and related modelling, algebra, and graphing. This includes work on the expansion and factorisation of quadratic expressions (typically with integer values of coefficients), graphing quadratic functions, finding the roots of quadratic…
ERIC Educational Resources Information Center
Motz, Benjamin A.; Erickson, Molly A.; Hetrick, William P.
2013-01-01
Humans perceive a wide range of temporal patterns, including those rhythms that occur in music, speech, and movement; however, there are constraints on the rhythmic patterns that we can represent. Past research has shown that sequences in which sounds occur regularly at non-metrical locations in a repeating beat period (non-integer ratio…
ERIC Educational Resources Information Center
Varma, Sashank; Schwartz, Daniel L.
2011-01-01
Mathematics has a level of structure that transcends untutored intuition. What is the cognitive representation of abstract mathematical concepts that makes them meaningful? We consider this question in the context of the integers, which extend the natural numbers with zero and negative numbers. Participants made greater and lesser judgments of…
ERIC Educational Resources Information Center
Kumar, Ruchi S.; Subramaniam, Kalyansundaram
2015-01-01
In this paper we describe four Indian in-service middle school mathematics teachers' shifts in their roles with respect to the textbook. The shifts occurred through participation in collaborative investigation on the topic of integers in professional development meetings. Analysis of teachers' talk in these meetings indicated a shift in teachers'…
ERIC Educational Resources Information Center
Gallardo, Aurora
2002-01-01
Analyzes from an historical perspective the extension of the natural-number domain to integers in students' transition from arithmetic to algebra in the context of word problems. Extracts four levels of acceptance of these numbers--subtrahend, relative number, isolated number and formal negative number--from historical texts. The first three…
NASA Astrophysics Data System (ADS)
Minatsuki, Isao; Fukui, Hiroshi; Ishino, Kazuo
The hydrogen production method applying thermo-chemical Iodine-Sulfur process (IS process) which uses a nuclear high temperature gas cooled reactor is world widely greatly concerned from the view point of a combination as a clean method, free carbon dioxide in essence. In this process, it is essential a using ceramic material, especially SiC because a operation condition of this process is very corrosive due to a sulfuric acid atmosphere with high temperature and high pressure. In the IS process, a sulfuric acid decomposer is the key component which performs evaporating of sulfuric acid from liquid to gas and disassembling to SO2 gas. SiC was selected as ceramic material to apply for the sulfuric acid decomposer and a new type of binding material was also developed for SiC junction. This technology is expected to wide application not only for a sulfuric acid decomposer but also for various type components in this process. Process parameters were provided as design condition for the decomposer. The configuration of the sulfuric acid decomposer was studied, and a cylindrical tubes assembling type was selected. The advantage of this type is applicable for various type of components in the IS process due to manufacturing with using only simple shape part. A sulfuric acid decomposer was divided into two regions of the liquid and the gaseous phase of sulfuric acid. The thermal structural integrity analysis was studied for the liquid phase part. From the result of this analysis, it was investigated that the stress was below the strength of the breakdown probability 1/100,000 at any position, base material or junction part. The prototype model was manufactured, which was a ceramic portion in the liquid phase part, comparatively complicated configuration, of a sulfuric acid decomposer. The size of model was about 1.9m in height, 1.0m in width. Thirty-six cylinders including inlet and outlet nozzles were combined and each part article was joined using the new binder (slurry
Hiroshi Fukui; Isao Minatsuki; Kazuo Ishino
2006-07-01
The hydrogen production method applying thermo-chemical Iodine-Sulfur process (IS process) which uses a nuclear high temperature gas cooled reactor is world widely greatly concerned from the view point of a combination as a clean method, free carbon dioxide in essence. In this process, it is essential a using ceramic material, especially SiC because a operation condition of this process is very corrosive due to a sulfuric acid atmosphere with high temperature and high pressure. In the IS process, a sulfuric acid decomposer is the key component which performs evaporating of sulfuric acid from liquid to gas and disassembling to SO{sub 2} gas. SiC was selected as ceramic material to apply for the sulfuric acid decomposer and a new type of binding material was also developed for SiC junction. This technology is expected to wide application not only for a sulfuric acid decomposer but also for various type components in this process. Process parameters were provided as design condition for the decomposer. The configuration of the sulfuric acid decomposer was studied, and a cylindrical tubes assembling type was selected. The advantage of this type is applicable for various type of components in the IS process due to manufacturing with using only simple shape part. A sulfuric acid decomposer was divided into two regions of the liquid and the gaseous phase of sulfuric acid. The thermal structural integrity analysis was studied for the liquid phase part. From the result of this analysis, it was investigated that the stress was below the strength of the breakdown probability 1/100,000 at any position, base material or junction part. The prototype model was manufactured, which was a ceramic portion in the liquid phase part, comparatively complicated configuration, of a sulfuric acid decomposer. The size of model was about 1.9 m in height, 1.0 m in width. Thirty-six cylinders including inlet and outlet nozzles were combined and each part article was joined using the new binder
Instantaneous and controllable integer ambiguity resolution: review and an alternative approach
NASA Astrophysics Data System (ADS)
Zhang, Jingyu; Wu, Meiping; Li, Tao; Zhang, Kaidong
2015-11-01
In the high-precision application of Global Navigation Satellite System (GNSS), integer ambiguity resolution is the key step to realize precise positioning and attitude determination. As the necessary part of quality control, integer aperture (IA) ambiguity resolution provides the theoretical and practical foundation for ambiguity validation. It is mainly realized by acceptance testing. Due to the constraint of correlation between ambiguities, it is impossible to realize the controlling of failure rate according to analytical formula. Hence, the fixed failure rate approach is implemented by Monte Carlo sampling. However, due to the characteristics of Monte Carlo sampling and look-up table, we have to face the problem of a large amount of time consumption if sufficient GNSS scenarios are included in the creation of look-up table. This restricts the fixed failure rate approach to be a post process approach if a look-up table is not available. Furthermore, if not enough GNSS scenarios are considered, the table may only be valid for a specific scenario or application. Besides this, the method of creating look-up table or look-up function still needs to be designed for each specific acceptance test. To overcome these problems in determination of critical values, this contribution will propose an instantaneous and CONtrollable (iCON) IA ambiguity resolution approach for the first time. The iCON approach has the following advantages: (a) critical value of acceptance test is independently determined based on the required failure rate and GNSS model without resorting to external information such as look-up table; (b) it can be realized instantaneously for most of IA estimators which have analytical probability formulas. The stronger GNSS model, the less time consumption; (c) it provides a new viewpoint to improve the research about IA estimation. To verify these conclusions, multi-frequency and multi-GNSS simulation experiments are implemented. Those results show that IA
Iuga, D; Schäfer, H; Verhagen, R; Kentgens, A P
2000-12-01
We have recently shown that the sensitivity of single- and multiple-quantum NMR experiments of half-integer (N/2) quadrupolar nuclei can be increased significantly by introducing so-called double frequency sweeps (DFS) in various pulse schemes. These sweeps consist of two sidebands generated by an amplitude modulation of the RF carrier. Using a time-dependent amplitude modulation the sidebands can be swept through a certain frequency range. Inspired by the work of Vega and Naor (J. Chem. Phys. 75, 75 (1981)), this is used to manipulate +/-(m - 1) <--> +/-m (3/2 < or = m < or = N/2) satellite transitions in half-integer spin systems simultaneously. For (23)Na (I = 3/2) and (27)Al (I = 5/2) spins in single crystals it proved possible to transfer the populations of the outer +/-m spin levels to the inner +/-1/2 spin levels. A detailed analysis shows that the efficiency of this process is a function of the adiabaticity with which the various spin transitions are passed during the sweep. In powders these sweep parameters have to be optimized to satisfy the appropriate conditions for a maximum of spins in the powder distribution. The effects of sweep rate, sweep range, and RF field strength are investigated both numerically and experimentally. Using a DFS as a preparation period leads to significantly enhanced central transition powder spectra under both static and MAS conditions, compared to single pulse excitation. DFSs prove to be very efficient tools not only for population transfer, but also for coherence transfer. This can be exploited for the multiple- to single-quantum transfer in MQMAS experiments. It is demonstrated, theoretically and experimentally, that DFSs are capable of transferring both quintuple-quantum and triple-quantum coherence into single-quantum coherence in I = 5/2 spin systems. This leads to a significant enhancement in signal-to-noise ratio and strongly reduces the RF power requirement compared to pulsed MQMAS experiments, thus extending their
Decomposing retrieval and integration in memory for actions: a multinomial modeling approach.
Steffens, Melanie C; Jelenec, Petra; Mecklenbräuker, Silvia; Thompson, Erin Marie
2006-03-01
Typically, action phrases are recalled better if participants are asked to enact the phrases than if they are just asked to remember them. When investigating which processes constitute this enactment effect a difficulty is that observable effects in standard memory tests are ambiguous because such tests require several processes. In the present article, we introduce a multinomial model that decomposes observable memory performance into a retrieval parameter and a parameter concerning the item-specific processing and integration of an action phrase. These parameters are estimated from free recall and cued recall performance. The model fitted the data of two experiments designed to test it. Experiment 1 demonstrated the basic usefulness of the model by showing expected differences in the integration parameter in the absence of unexpected differences in the retrieval parameter. Experiment 2 extended the conditions under which the model is useful by showing expected differences in the retrieval parameter even in the presence of unexpected differences in the integration parameter. Together, these findings support our theoretical framework according to which enactment generally boosts integration of action phrases, but increases retrieval only for phrases with context cues. PMID:16627356
Using decision models to decompose anxiety-related bias in threat classification.
White, Corey N; Skokin, Kimberly; Carlos, Brandon; Weaver, Alexandria
2016-03-01
Individuals with high levels of anxiety show preferential processing of threatening information, and this cognitive bias is thought to be an integral component of anxiety disorders. In threat classification tasks, this bias manifests as high-anxiety participants being more likely to classify stimuli as threatening than their low-anxiety counterparts. However, it is unclear which cognitive mechanisms drive this bias in threat classification. To better understand this phenomenon, threat classification data were analyzed with 2 decision models: a signal detection model and a drift-diffusion model. Signal detection models can dissociate measures of discriminability and bias, and diffusion models can further dissociate bias due to response preparation from bias due to stimulus evaluation. Individuals in the study completed a trait anxiety measure and classified threatening and neutral words based on whether they deemed them threatening. Signal detection analysis showed that high-anxiety participants had a bias driven by a weaker threat criterion than low-anxiety participants, but no differences in discriminability. Drift-diffusion analysis further decomposed the threat bias to show that it is driven by both an expectation bias that the threat response was more likely to be correct, and a stimulus bias driven by a weaker criterion for evaluating the stimuli under consideration. These model-based analyses provide valuable insight and show that multiple cognitive mechanisms underlie differential threat processing in anxiety. Implications for theories of anxiety are discussed.
Tano, T; Kitaguchi, H; Harada, M; Nagasawa, T; Sugio, T
1996-01-01
A tetrathionate-decomposing enzyme that catalyzes the decomposition of tetrathionate into thiosulfate and sulfate was purified to homogeneity from tetrathionate-grown Thiobacillus thiooxidans. The enzyme had an apparent molecular weight of 104,000, and was composed of two identical subunits (MW = 58,000) as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme had an isoelectric point at 9.6 and was most active at pH 3.0-3.5 and 40°C. Enzyme activity was increased approximately 100-fold in the presence of 400 mm sulfate ion. The Michaelis constant of this enzyme for tetrathionate in the presence of 20, 50, and 200 mm of sulfate ion was 2.4 mm. Mercuric and ferric ions completely inhibited the enzyme activity at 1 mm. Though cupric ion up to 0.01 mm markedly stimulated the activity in the presence of 20 mm sulfate ion, a higher concentration (1 mm) rather strongly inhibited the activity. Ethylenediaminetetraacetic acid (EDTA) strongly inhibited the activity, but this inhibiton was completely restored by cupric ion.
O'Brien, M. J.; Brantley, P. S.
2015-01-20
In order to run Monte Carlo particle transport calculations on new supercomputers with hundreds of thousands or millions of processors, care must be taken to implement scalable algorithms. This means that the algorithms must continue to perform well as the processor count increases. In this paper, we examine the scalability of:(1) globally resolving the particle locations on the correct processor, (2) deciding that particle streaming communication has finished, and (3) efficiently coupling neighbor domains together with different replication levels. We have run domain decomposed Monte Carlo particle transport on up to 2^{21} = 2,097,152 MPI processes on the IBM BG/Q Sequoia supercomputer and observed scalable results that agree with our theoretical predictions. These calculations were carefully constructed to have the same amount of work on every processor, i.e. the calculation is already load balanced. We also examine load imbalanced calculations where each domain’s replication level is proportional to its particle workload. In this case we show how to efficiently couple together adjacent domains to maintain within workgroup load balance and minimize memory usage.
Decomposing the effects of children's health on mother's labor supply: is it time or money?
Gould, Elise
2004-06-01
In this paper, I explore how children's health influences the wages and work hours of their mother. Some children have illnesses that require expensive medicine or treatment, but demand little parental time. Others require extraordinary amounts of time; and still others require care at unpredictable times of the day. I construct a theoretical model of mother's labor supply that explicitly incorporates the financial and time costs associated with the presence of unhealthy children. The model predicts that children with time-intensive illnesses and those with unpredictable illnesses negatively influence mother's labor supply, whereas children with illnesses with a strong financial component have a positive effect on mother's labor supply. In order to empirically test this, I organize a focus group of doctors to categorize illnesses and disabilities by the type of resources they require. Using the 1997 PSID Child Development Supplement, I estimate the effects of these requirements on mother's decision to work and work hours. After controlling for the financial burden of the illness, single mothers work fewer hours if their child has a time-intensive illness and married mothers are less likely to work and work fewer hours if their child has a severe condition with an unpredictable time component. These findings are consistent with the theoretical model and highlight the need to decompose the effects of child health on mother's work status. Model specifications that aggregate across illnesses are incapable of disentangling these effects and may therefore underestimate the welfare costs of having a sick child in the family.
A phytotoxic active substance in the decomposing litter of the fern Gleichenia japonica.
Kato-Noguchi, Hisashi; Saito, Yoshihumi; Ohno, Osamu; Suenaga, Kiyotake
2015-03-15
The fern Gleichenia japonica often dominates plant communities by forming large monospecific stands throughout the temperate to tropical Asia. The objective of this study was the investigation of allelopathic property and substances of the decomposing litter of the fern to evaluate the possible involvement of its allelopathy in the domination. An aqueous methanol extract of G. japonica litter inhibited the growth of garden cress (Lepidium sativum), lettuce (Lactuca sativa), barnyard grass (Echinochloa crus-galli), and ryegrass (Lolium multiflorum). This result suggests that G. japonica litter contains growth inhibitory substances. The extract was purified by chromatography while monitoring the inhibitory activity, and a growth inhibitory substance was isolated. The chemical structure of the substance was determined by spectral data to be a novel compound, 13-O-β-fucopyranosyl-3β-hydroxymanool. This compound inhibited root and shoot growth of garden cress and barnyard grass at concentrations ranging from 89.7 to 271 μM for 50% inhibition. In addition, the compound had potent growth inhibitory activity with the soil taken from near the colony. The concentration of the compound in soil under a pure colony of G. japonica was 790 μM, suggesting that the compound may contribute to the establishment of monocultural stands by this fern.
The potential and limits of termites (Isoptera) as decomposers of waste paper products.
Lenz, Michael; Lee, Chow-Yang; Lacey, Michael J; Yoshimura, Tsuyoshi; Tsunoda, Kunio
2011-02-01
Termites (Isoptera) have often been proposed as decomposers oflignocellulosic waste, such as paper products, while termite biomass could be harvested for food supplements. Groups of Coptotermes formosanus Shiraki and Reticulitermes speratus (Kolbe) were kept for 4 and 8 wk, respectively, in the laboratory and given up to 10 different types of paper as their food source. Paper consumption, survival, caste composition, and lipid content were recorded. Corrugated cardboard was by far the most consumed paper product, although survival on it was not necessarily favorable. In R. speratus, lipid reserves and neotenic numbers were quite high, but no breeding occurred. Cardboard may be the "junk food" equivalent for termites. Within the tested period, termites did not perform well on paper products that form the bulk of waste paper--corrugated cardboard, newsprint, and pamphlets and magazines. On all paper products (except recycled office paper), neotenic reproductives were formed, but larvae were observed only on kraft pulp and tissue paper. That all waste paper products contain lignocellulosic fibers does not automatically make them suitable for decomposition by termites. Each paper product has to be assessed on its own merit to see whether termites can reproduce on this diet, if it were to be a candidate for sustainable "termidegradation" and termite biomass production.
Yang, Seung Hak; Lim, Joung Soo; Khan, Modabber Ahmed; Kim, Bong Soo; Choi, Dong Yoon; Lee, Eun Young; Ahn, Hee Kwon
2015-01-01
The leachate generated by the decomposition of animal carcass has been implicated as an environmental contaminant surrounding the burial site. High-throughput nucleotide sequencing was conducted to investigate the bacterial communities in leachates from the decomposition of pig carcasses. We acquired 51,230 reads from six different samples (1, 2, 3, 4, 6 and 14 week-old carcasses) and found that sequences representing the phylum Firmicutes predominated. The diversity of bacterial 16S rRNA gene sequences in the leachate was the highest at 6 weeks, in contrast to those at 2 and 14 weeks. The relative abundance of Firmicutes was reduced, while the proportion of Bacteroidetes and Proteobacteria increased from 3–6 weeks. The representation of phyla was restored after 14 weeks. However, the community structures between the samples taken at 1–2 and 14 weeks differed at the bacterial classification level. The trend in pH was similar to the changes seen in bacterial communities, indicating that the pH of the leachate could be related to the shift in the microbial community. The results indicate that the composition of bacterial communities in leachates of decomposing pig carcasses shifted continuously during the study period and might be influenced by the burial site. PMID:26500442
Decomposing Kenyan socio-economic inequalities in skilled birth attendance and measles immunization
2013-01-01
Introduction Skilled birth attendance (SBA) and measles immunization reflect two aspects of a health system. In Kenya, their national coverage gaps are substantial but could be largely improved if the total population had the same coverage as the wealthiest quintile. A decomposition analysis allows identifying the factors that influence these wealth-related inequalities in order to develop appropriate policy responses. The main objective of the study was to decompose wealth-related inequalities in SBA and measles immunization into their contributing factors. Methods Data from the Kenyan Demographic and Health Survey 2008/09 were used. The study investigated the effects of socio-economic determinants on [1] coverage and [2] wealth-related inequalities of SBA utilization and measles immunization. Techniques used were multivariate logistic regression and decomposition of the concentration index (C). Results SBA utilization and measles immunization coverage differed according to household wealth, parent’s education, skilled antenatal care visits, birth order and father’s occupation. SBA utilization further differed across provinces and ethnic groups. The overall C for SBA was 0.14 and was mostly explained by wealth (40%), parent’s education (28%), antenatal care (9%), and province (6%). The overall C for measles immunization was 0.08 and was mostly explained by wealth (60%), birth order (33%), and parent’s education (28%). Rural residence (−19%) reduced this inequality. Conclusion Both health care indicators require a broad strengthening of health systems with a special focus on disadvantaged sub-groups. PMID:23294938
Decomposing the Drivers of Past, Present, and Future Land Use Change
NASA Astrophysics Data System (ADS)
Calvin, K. V.; Wise, M. A.
2015-12-01
Over the past 500 years, global agricultural area has grown from 2 million km2 (1500) to 15 million km2 (2005), displacing forests and other natural ecosystems in the process (Hurtt et al., 2011). This expansion in area has been driven by changes in population, income, diet, and agricultural productivity. These factors will continue to evolve in the future; however, the effect of these changes on future land use, land cover, and emissions remains uncertain (e.g., Calvin et al., In Press). Additionally, future changes in land depend critically on the implementation of land-based mitigation options, such as bioenergy and afforestation (Wise et al., 2009; Reilly et al., 2012; Popp et al., 2013; Calvin et al., 2014). As all of these factors are uncertain in the future, the future evolution of land use and land cover is also uncertain. This presentation decomposes the drivers of past, present, and future land use change, characterizing the contribution of factors such as population, income, diet, agricultural productivity, and mitigation. In the historical period, we rely on a variety of land-based datasets (e.g., FAO, HYDE). For the future period, we analyze the integrated assessment modeling community's implementation of the Shared Socioeconomic Pathways (SSPs; O'Neill et al., In Press). The SSPs describe five different evolutions of socioeconomic development, varying several factors relevant to land use and land use change.
A spectral analysis of the domain decomposed Monte Carlo method for linear systems
Slattery, Stuart R.; Evans, Thomas M.; Wilson, Paul P. H.
2015-09-08
The domain decomposed behavior of the adjoint Neumann-Ulam Monte Carlo method for solving linear systems is analyzed using the spectral properties of the linear oper- ator. Relationships for the average length of the adjoint random walks, a measure of convergence speed and serial performance, are made with respect to the eigenvalues of the linear operator. In addition, relationships for the effective optical thickness of a domain in the decomposition are presented based on the spectral analysis and diffusion theory. Using the effective optical thickness, the Wigner rational approxi- mation and the mean chord approximation are applied to estimate the leakagemore » frac- tion of random walks from a domain in the decomposition as a measure of parallel performance and potential communication costs. The one-speed, two-dimensional neutron diffusion equation is used as a model problem in numerical experiments to test the models for symmetric operators with spectral qualities similar to light water reactor problems. We find, in general, the derived approximations show good agreement with random walk lengths and leakage fractions computed by the numerical experiments.« less
A spectral analysis of the domain decomposed Monte Carlo method for linear systems
Slattery, Stuart R.; Evans, Thomas M.; Wilson, Paul P. H.
2015-09-08
The domain decomposed behavior of the adjoint Neumann-Ulam Monte Carlo method for solving linear systems is analyzed using the spectral properties of the linear oper- ator. Relationships for the average length of the adjoint random walks, a measure of convergence speed and serial performance, are made with respect to the eigenvalues of the linear operator. In addition, relationships for the effective optical thickness of a domain in the decomposition are presented based on the spectral analysis and diffusion theory. Using the effective optical thickness, the Wigner rational approxi- mation and the mean chord approximation are applied to estimate the leakage frac- tion of random walks from a domain in the decomposition as a measure of parallel performance and potential communication costs. The one-speed, two-dimensional neutron diffusion equation is used as a model problem in numerical experiments to test the models for symmetric operators with spectral qualities similar to light water reactor problems. We find, in general, the derived approximations show good agreement with random walk lengths and leakage fractions computed by the numerical experiments.
NASA Astrophysics Data System (ADS)
Shapoori, V.; Peterson, T. J.; Western, A. W.; Costelloe, J. F.
2015-11-01
Time-series modeling is often used to decompose groundwater hydrographs into individual drivers such as pumping and meteorological factors. To date, there has been an assumption that a simulation fitting the total hydrograph produces reliable estimates of the impact from each driver. That is, assessment of the decomposition has not used an independent estimate of each decomposition result. To begin to address this, a synthetic study is undertaken so that the impact of each driver is known. In this study, 500 MODFLOW groundwater models of a one-layer unconfined aquifer were constructed. For each model, three hydrogeological properties (saturated hydraulic conductivity, storativity and depth to aquifer basement), the distance between observation and pumping bores, and extraction rate were set randomly and synthetic groundwater hydrographs were derived. For each hydrograph, the influence of individual drivers was estimated using six different time-series models. These estimates were then compared to the known meteorological and pumping influences derived from the MODFLOW models. The results demonstrate that hydrograph separations obtained from time-series models do not always result in reliable estimation of pumping and meteorological influences even when the overall hydrograph fit is good. However, when the time-series model represents the important processes (e.g. phreatic evaporation is included for shallow water tables) and the (head) variance of the pumping signal to the meteorological signal is between 0.1 and 10, the time-series model has the potential to adequately separate the influence of pumping and climate.
A phytotoxic active substance in the decomposing litter of the fern Gleichenia japonica.
Kato-Noguchi, Hisashi; Saito, Yoshihumi; Ohno, Osamu; Suenaga, Kiyotake
2015-03-15
The fern Gleichenia japonica often dominates plant communities by forming large monospecific stands throughout the temperate to tropical Asia. The objective of this study was the investigation of allelopathic property and substances of the decomposing litter of the fern to evaluate the possible involvement of its allelopathy in the domination. An aqueous methanol extract of G. japonica litter inhibited the growth of garden cress (Lepidium sativum), lettuce (Lactuca sativa), barnyard grass (Echinochloa crus-galli), and ryegrass (Lolium multiflorum). This result suggests that G. japonica litter contains growth inhibitory substances. The extract was purified by chromatography while monitoring the inhibitory activity, and a growth inhibitory substance was isolated. The chemical structure of the substance was determined by spectral data to be a novel compound, 13-O-β-fucopyranosyl-3β-hydroxymanool. This compound inhibited root and shoot growth of garden cress and barnyard grass at concentrations ranging from 89.7 to 271 μM for 50% inhibition. In addition, the compound had potent growth inhibitory activity with the soil taken from near the colony. The concentration of the compound in soil under a pure colony of G. japonica was 790 μM, suggesting that the compound may contribute to the establishment of monocultural stands by this fern. PMID:25569852
Komar, Debra; Lathrop, Sarah; Potter, Wendy
2008-12-01
Analysis of mass death events, often involving partial or skeletal human remains, requires investigators to condense information on a large number of victims into a single report. Prosecution of war crimes typically requires that victims be categorized according to the injuries sustained. Reports recognizing only the presence or absence of trauma are misleading or misrepresentative. This study introduces a 4 class system for skeletal remains based on morphologic autopsy findings. Each class corresponds to the lethal potential of the trauma or pathologic conditions evident at autopsy, and the certainty with which cause of death can be determined. Data were extracted from 766 autopsy cases involving decomposed or skeletal remains from the New Mexico Office of the Medical Investigator in which cause and manner of death were ruled. Statistically significant associations between morphology class and the cause and manner of death, positive identification, and natural and non-natural deaths were evident in this study. Intraobserver and interobserver tests revealed excellent replicability and reliability in the assignment of morphology classes to individual cases. In addition to its mass death applications, this classification system offers potential research contributions to physical anthropologists and bioarchaeologists studying human populations in antiquity.
NASA Astrophysics Data System (ADS)
Griffiths, K. R.; Hicks, B. J.; Keogh, P. S.; Shires, D.
2016-08-01
In general, vehicle vibration is non-stationary and has a non-Gaussian probability distribution; yet existing testing methods for packaging design employ Gaussian distributions to represent vibration induced by road profiles. This frequently results in over-testing and/or over-design of the packaging to meet a specification and correspondingly leads to wasteful packaging and product waste, which represent 15bn per year in the USA and €3bn per year in the EU. The purpose of the paper is to enable a measured non-stationary acceleration signal to be replaced by a constructed signal that includes as far as possible any non-stationary characteristics from the original signal. The constructed signal consists of a concatenation of decomposed shorter duration signals, each having its own kurtosis level. Wavelet analysis is used for the decomposition process into inner and outlier signal components. The constructed signal has a similar PSD to the original signal, without incurring excessive acceleration levels. This allows an improved and more representative simulated input signal to be generated that can be used on the current generation of shaker tables. The wavelet decomposition method is also demonstrated experimentally through two correlation studies. It is shown that significant improvements over current international standards for packaging testing are achievable; hence the potential for more efficient packaging system design is possible.
Mutagenicity and DNA-damaging activity of decomposed products of food colours under UV irradiation.
Ozaki, A; Kitano, M; Itoh, N; Kuroda, K; Furusawa, N; Masuda, T; Yamaguchi, H
1998-01-01
Five synthetic food colours Food Red Nos 3, 40 and 102 and Food Blue Nos 1 and 2, and their UV irradiated products were tested for mutagenic activity by means of the Ames test using Salmonella typhimurium strains TA98 and TA100. Food colours were irradiated with UV light for 14 days. Food Red Nos 3, 40 and 102 and Food Blue No. 1 were non-mutagenic before and after irradiation. UV irradiated products of Food Blue No. 2 were mutagenic in TA98 with or without S-9 mix. The mutagenic activity increased with increasing irradiation period, reached maximum potency on day 6, and then decreased. Moreover, Food Blue No. 2 showed DNA-damaging activity after 14 days of irradiation in rec-assay using Bacillus subtilis strains H17 and M45. The capillary electrophoresis was applied for the analysis of UV irradiated products of Food Blue No. 2. The original peak of Food Blue No. 2 was decomposed into seven peaks after UV irradiation.
Effects of fungicides on decomposer communities and litter decomposition in vineyard streams.
Fernández, Diego; Voss, Katharina; Bundschuh, Mirco; Zubrod, Jochen P; Schäfer, Ralf B
2015-11-15
Large amounts of fungicides are applied globally and partly enter freshwater ecosystems. A few laboratory studies examined their effects on decomposer communities and the ecosystem process of litter decomposition (LD), whereas the field situation remains largely unknown. We conducted a field study with 17 stream sites in a German vineyard area where fungicides represent the dominant pest control agent. Passive samplers were used to monitor 15 fungicides and 4 insecticides in streams and their toxicity was described using the toxic unit approach, whereas sediment samples were taken to characterise total copper concentrations. Microbial and leaf-shredding invertebrate community composition and related LD rates were assessed at each site. The structure of microbial and shredder communities as well as fungal biomass changed along the fungicide toxicity gradient. The changes in microbial endpoints were associated with a reduction of microbial LD rate of up to 40% in polluted streams. By contrast, neither the invertebrate LD rate nor in-situ measured gammarid feeding rates correlated with fungicide toxicity, but both were negatively associated with sediment copper concentrations. A subsequent laboratory experiment employing field fungicide concentrations suggested that the microbial community changes are causal. Overall, our results suggest that fungicides can affect LD under field conditions.
A Linear Programming Solution to the Faculty Assignment Problem
ERIC Educational Resources Information Center
Breslaw, Jon A.
1976-01-01
Investigates the problem of assigning faculty to courses at a university. A program is developed that is both efficient, in that integer programming is not required, and effective, in that it facilitates interaction by administration in determining the optimal solution. The results of some empirical tests are also reported. (Author)
ERIC Educational Resources Information Center
Dos Santos, Luiz Miguel Renda; Okazaki, Shintaro
2013-01-01
This study sheds light on the organizational dimensions underlying e-learning adoption among Brazilian universities. We propose an organizational e-learning adoption model based on the decomposed theory of planned behavior (TPB). A series of hypotheses are posited with regard to the relationships among the proposed constructs. The model is…
A FASTQ compressor based on integer-mapped k-mer indexing for biologist.
Zhang, Yeting; Patel, Khyati; Endrawis, Tony; Bowers, Autumn; Sun, Yazhou
2016-03-15
Next generation sequencing (NGS) technologies have gained considerable popularity among biologists. For example, RNA-seq, which provides both genomic and functional information, has been widely used by recent functional and evolutionary studies, especially in non-model organisms. However, storing and transmitting these large data sets (primarily in FASTQ format) have become genuine challenges, especially for biologists with little informatics experience. Data compression is thus a necessity. KIC, a FASTQ compressor based on a new integer-mapped k-mer indexing method, was developed (available at http://www.ysunlab.org/kic.jsp). It offers high compression ratio on sequence data, outstanding user-friendliness with graphic user interfaces, and proven reliability. Evaluated on multiple large RNA-seq data sets from both human and plants, it was found that the compression ratio of KIC had exceeded all major generic compressors, and was comparable to those of the latest dedicated compressors. KIC enables researchers with minimal informatics training to take advantage of the latest sequence compression technologies, easily manage large FASTQ data sets, and reduce storage and transmission cost. PMID:26743127
NASA Astrophysics Data System (ADS)
Lyanda-Geller, Yuli; Simion, George
2015-03-01
We investigate a ground state of the two-dimensional (2D) electron liquid in the presence of disorder for Landau level filling factors, for which the re-entrant integer quantum Hall effect is observed. Our particular interest is the range of filling factors, which in a clean 2D system is favorable to formation of the two-electron (2e) bubble crystal. For the smooth random potential due to charged impurities placed far away from the 2D gas, the ground state is a lightly distorted 2e bubble crystal. However, for positively or negatively charged residual impurities located approximately within about three magnetic lengths from the 2D electrons, the ground state contains charged 2e complexes formed either by positively charged impurity and 3e defect bubble, or negatively charged impurity and 2e defect bubble. In the vicinity of 1e and 3e defect bubbles, the 2e bubbles of the crystal change their shape from round to elongated forming hedgehog (for 1e defect) or vortex (for 3e defect) textures. The topological textures due to these complexes interact with vortex and hedgehog excitations, generated as temperature increases that are not bound by residual impurities. The temperature of insulator to metal transition calculated with both bound and unbound defects agrees with experiment. Research was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Award DE-SC0010544.
Tracking Simulation of Third-Integer Resonant Extraction for Fermilab's Mu2e Experiment
Park, Chong Shik; Amundson, James; Michelotti, Leo
2015-02-13
The Mu2e experiment at Fermilab requires acceleration and transport of intense proton beams in order to deliver stable, uniform particle spills to the production target. To meet the experimental requirement, particles will be extracted slowly from the Delivery Ring to the external beamline. Using Synergia2, we have performed multi-particle tracking simulations of third-integer resonant extraction in the Delivery Ring, including space charge effects, physical beamline elements, and apertures. A piecewise linear ramp profile of tune quadrupoles was used to maintain a constant averaged spill rate throughout extraction. To study and minimize beam losses, we implemented and introduced a number of features, beamline element apertures, and septum plane alignments. Additionally, the RF Knockout (RFKO) technique, which excites particles transversely, is employed for spill regulation. Combined with a feedback system, it assists in fine-tuning spill uniformity. Simulation studies were carried out to optimize the RFKO feedback scheme, which will be helpful in designing the final spill regulation system.
Wang, Jing; Zhou, Quan; Lian, Biao; Zhang, Shou -Cheng
2015-08-31
Here, we propose to realize a two-dimensional chiral topological superconducting (TSC) state from the quantum anomalous Hall plateau transition in a magnetic topological insulator thin film through the proximity effect to a conventional s -wave superconductor. This state has a full pairing gap in the bulk and a single chiral Majorana mode at the edge. The optimal condition for realizing such chiral TSC is to have inequivalent superconducting pairing amplitudes on top and bottom surfaces of the doped magnetic topological insulator. We further propose several transport experiments to detect the chiral TSC. One unique signature is that the conductance will be quantized into a half-integer plateau at the coercive field in this hybrid system. In particular, with the point contact formed by a superconducting junction, the conductance oscillates between e^{2} /2h and e2 /h with the frequency determined by the voltage across the junction. We close by discussing the feasibility of these experimental proposals.
Short-range interactions and scaling near integer quantum Hall transitions
Wang, Ziqiang; Fisher, Matthew P. A.; Girvin, S. M.; Chalker, J. T.
2000-03-15
We study the influence of short-range electron-electron interactions on scaling behavior near the integer quantum Hall plateau transitions. Short-range interactions are known to be irrelevant at the renormalization group fixed point which represents the transition in the noninteracting system. We find, nevertheless, that transport properties change discontinuously when interactions are introduced. Most importantly, in the thermodynamic limit the conductivity at finite temperature is zero without interactions, but nonzero in the presence of arbitrarily weak interactions. In addition, scaling as a function of frequency {omega} and temperature T is determined by the scaling variable {omega}/T{sup p} (where p is the exponent for the temperature dependence of the inelastic scattering rate) and not by {omega}/T, as it would be at a conventional quantum phase transition described by an interacting fixed point. We express the inelastic exponent p and the thermal exponent z{sub T} in terms of the scaling dimension -{alpha}<0 of the interaction strength and the dynamical exponent z (which has the value z=2), obtaining p=1+2{alpha}/z and z{sub T}=2/p. (c) 2000 The American Physical Society.
Theory of the Half-integer Quantum Hall Effect in Graphene
NASA Astrophysics Data System (ADS)
Fujita, Shigeji; Suzuki, Akira
2016-08-01
The unusual quantum Hall effect (QHE) in graphene is described in terms of the composite (c-) bosons, which move with a linear dispersion relation. The "electron" (wave packet) moves easier in the direction [1 1 0 c-axis] ≡ [1 1 0] of the honeycomb lattice than perpendicular to it, while the "hole" moves easier in [0 0 1]. Since "electrons" and "holes" move in different channels, the particle densities can be high especially when the Fermi surface has "necks". The strong QHE arises from the phonon exchange attraction in the neighborhood of the "neck" surfaces. The plateau observed for the Hall conductivity and the accompanied resistivity drop is due to the superconducting energy gap caused by the Bose-Einstein condensation of the c-bosons, each forming from a pair of one-electron-two-fluxons c-fermions by phonon-exchange attraction. The half-integer quantization rule for the Hall conductivity: (1/2)(2P-1)(4e 2/h), P=1,2,..., is derived.
Wang, Jing; Zhou, Quan; Lian, Biao; Zhang, Shou -Cheng
2015-08-31
Here, we propose to realize a two-dimensional chiral topological superconducting (TSC) state from the quantum anomalous Hall plateau transition in a magnetic topological insulator thin film through the proximity effect to a conventional s -wave superconductor. This state has a full pairing gap in the bulk and a single chiral Majorana mode at the edge. The optimal condition for realizing such chiral TSC is to have inequivalent superconducting pairing amplitudes on top and bottom surfaces of the doped magnetic topological insulator. We further propose several transport experiments to detect the chiral TSC. One unique signature is that the conductance willmore » be quantized into a half-integer plateau at the coercive field in this hybrid system. In particular, with the point contact formed by a superconducting junction, the conductance oscillates between e2 /2h and e2 /h with the frequency determined by the voltage across the junction. We close by discussing the feasibility of these experimental proposals.« less
NASA Astrophysics Data System (ADS)
Thompson, Evan
2014-09-01
Pessoa's review [4] casts new light on a deep and difficult question: is the brain a "decomposable" or "nondecomposable" system [1,5,7]? This question pertains to the functional organization of the brain as a cognitive system. In a decomposable system, each subsystem's operation is determined by the subsystem's intrinsic properties independent of the other subsystems, making the system's organization strongly modular. Modularity decreases depending on how strongly the subsystems interact, especially through feedback and reentrant or recursive processes. If the subsystems are only weakly coupled, such that the causal interactions within a subsystem play a stronger role in determining its operation than do the causal interactions between it and other subsystems, then the system is "nearly decomposable." If the subsystems are strongly coupled, then the functional organization of the system becomes less governed by the intrinsic properties of its subsystems and more governed by the ways the subsystems interact, making the system "minimally decomposable." In a "nondecomposable" system, the coupling is such that the subsystems no longer have clearly separable operations apart from the larger context of their interdependent operation. (Note that such strong coupling can involve weak local connections, as Pessoa discusses in Section 9.1.) The current debate about whether cognitive functions can be localized to specific brain regions [2], or whether cognitive functions need to be mapped onto dynamic networks instantiated in shifting coalitions or assemblies of regions [3,6], can be regarded also as a debate about the extent to which the brain's cognitive organization is decomposable (modular) or nondecomposable (nonmodular).
Double loaded self-decomposable SiO2 nanoparticles for sustained drug release
NASA Astrophysics Data System (ADS)
Zhao, Saisai; Zhang, Silu; Ma, Jiang; Fan, Li; Yin, Chun; Lin, Ge; Li, Quan
2015-10-01
Sustained drug release for a long duration is a desired feature of modern drugs. Using double-loaded self-decomposable SiO2 nanoparticles, we demonstrated sustained drug release in a controllable manner. The double loading of the drugs was achieved using two different mechanisms--the first one via a co-growth mechanism, and the second one by absorption. A two-phase sustained drug release was firstly revealed in an in vitro system, and then further demonstrated in mice. After a single intravenous injection, the drug was controllably released from the nanoparticles into blood circulation with a Tmax of about 8 h, afterwards a long lasting release pattern was achieved to maintain drug systemic exposure with a plasma elimination half-life of approximately 28 h. We disclosed that the absorbed drug molecules contributed to the initial fast release for quickly reaching the therapeutic level with relatively higher plasma concentrations, while the ``grown-in'' drugs were responsible for maintaining the therapeutic level via the later controlled slow and sustained release. The present nanoparticle carrier drug configuration and the loading/maintenance release mechanisms provide a promising platform that ensures a prolonged therapeutic effect by controlling drug concentrations within the therapeutic window--a sustained drug delivery system with a great impact on improving the management of chronic diseases.Sustained drug release for a long duration is a desired feature of modern drugs. Using double-loaded self-decomposable SiO2 nanoparticles, we demonstrated sustained drug release in a controllable manner. The double loading of the drugs was achieved using two different mechanisms--the first one via a co-growth mechanism, and the second one by absorption. A two-phase sustained drug release was firstly revealed in an in vitro system, and then further demonstrated in mice. After a single intravenous injection, the drug was controllably released from the nanoparticles into blood
Wilson, P
2011-08-01
The UK dairy sector has undergone considerable structural change in recent years, with a decrease in the number of producers accompanied by an increased average herd size and increased concentrate use and milk yields. One of the key drivers to producers remaining in the industry is the profitability of their herds. The current paper adopts a holistic approach to decomposing the variation in dairy profitability through an analysis of net margin data explained by physical input-output measures, milk price variation, labour utilization and managerial behaviours and characteristics. Data are drawn from the Farm Business Survey (FBS) for England in 2007/08 for 228 dairy enterprises. Average yields are 7100 litres/cow/yr, from a herd size of 110 cows that use 0·56 forage ha/cow/yr and 43·2 labour h/cow/yr. An average milk price of 22·57 pence per litre (ppl) produced milk output of £1602/cow/yr, which after accounting for calf sales, herd replacements and quota leasing costs, gave an average dairy output of £1516/cow/yr. After total costs of £1464/cow/yr this left an economic return of £52/cow/yr (0·73 ppl) net margin profit. There is wide variation in performance, with the most profitable (as measured by net margin per cow) quartile of producers achieving 2000 litres/cow/yr more than the least profitable quartile, returning a net margin of £335/cow/yr compared to a loss of £361/cow/yr for the least profitable. The most profitable producers operate larger, higher yielding herds and achieve a greater milk price for their output. In addition, a significantly greater number of the most profitable producers undertake financial benchmarking within their businesses and operate specialist dairy farms. When examining the full data set, the most profitable enterprises included significantly greater numbers of organic producers. The most profitable tend to have a greater reliance on independent technical advice, but this finding is not statistically significant
WILSON, P.
2011-01-01
SUMMARY The UK dairy sector has undergone considerable structural change in recent years, with a decrease in the number of producers accompanied by an increased average herd size and increased concentrate use and milk yields. One of the key drivers to producers remaining in the industry is the profitability of their herds. The current paper adopts a holistic approach to decomposing the variation in dairy profitability through an analysis of net margin data explained by physical input–output measures, milk price variation, labour utilization and managerial behaviours and characteristics. Data are drawn from the Farm Business Survey (FBS) for England in 2007/08 for 228 dairy enterprises. Average yields are 7100 litres/cow/yr, from a herd size of 110 cows that use 0·56 forage ha/cow/yr and 43·2 labour h/cow/yr. An average milk price of 22·57 pence per litre (ppl) produced milk output of £1602/cow/yr, which after accounting for calf sales, herd replacements and quota leasing costs, gave an average dairy output of £1516/cow/yr. After total costs of £1464/cow/yr this left an economic return of £52/cow/yr (0·73 ppl) net margin profit. There is wide variation in performance, with the most profitable (as measured by net margin per cow) quartile of producers achieving 2000 litres/cow/yr more than the least profitable quartile, returning a net margin of £335/cow/yr compared to a loss of £361/cow/yr for the least profitable. The most profitable producers operate larger, higher yielding herds and achieve a greater milk price for their output. In addition, a significantly greater number of the most profitable producers undertake financial benchmarking within their businesses and operate specialist dairy farms. When examining the full data set, the most profitable enterprises included significantly greater numbers of organic producers. The most profitable tend to have a greater reliance on independent technical advice, but this finding is not statistically significant
Wilson, P
2011-08-01
The UK dairy sector has undergone considerable structural change in recent years, with a decrease in the number of producers accompanied by an increased average herd size and increased concentrate use and milk yields. One of the key drivers to producers remaining in the industry is the profitability of their herds. The current paper adopts a holistic approach to decomposing the variation in dairy profitability through an analysis of net margin data explained by physical input-output measures, milk price variation, labour utilization and managerial behaviours and characteristics. Data are drawn from the Farm Business Survey (FBS) for England in 2007/08 for 228 dairy enterprises. Average yields are 7100 litres/cow/yr, from a herd size of 110 cows that use 0·56 forage ha/cow/yr and 43·2 labour h/cow/yr. An average milk price of 22·57 pence per litre (ppl) produced milk output of £1602/cow/yr, which after accounting for calf sales, herd replacements and quota leasing costs, gave an average dairy output of £1516/cow/yr. After total costs of £1464/cow/yr this left an economic return of £52/cow/yr (0·73 ppl) net margin profit. There is wide variation in performance, with the most profitable (as measured by net margin per cow) quartile of producers achieving 2000 litres/cow/yr more than the least profitable quartile, returning a net margin of £335/cow/yr compared to a loss of £361/cow/yr for the least profitable. The most profitable producers operate larger, higher yielding herds and achieve a greater milk price for their output. In addition, a significantly greater number of the most profitable producers undertake financial benchmarking within their businesses and operate specialist dairy farms. When examining the full data set, the most profitable enterprises included significantly greater numbers of organic producers. The most profitable tend to have a greater reliance on independent technical advice, but this finding is not statistically significant
Stohlgren, Thomas J.
1988-01-01
The factors influencing leaf litter decomposition and nutrient release patterns were investigated for 3.6 years in two mixed conifer forests in the southern Sierra Nevada of California. The giant sequoia–fir forest was dominated by giant sequoia (Sequoiadendrongiganteum (Lindl.) Buchh.), white fir (Abiesconcolor Lindl. & Gord.), and sugar pine (Pinuslambertiana Dougl.). The fir–pine forest was dominated by white fir, sugar pine, and incense cedar (Calocedrusdecurrens (Torr.) Florin). Initial concentrations of nutrients and percent lignin, cellulose, and acid detergent fiber vary considerably in freshly abscised leaf litter of the studied species. Giant sequoia had the highest concentration of lignin (20.3%) and the lowest concentration of nitrogen (0.52%), while incense cedar had the lowest concentration of lignin (9.6%) and second lowest concentration of nitrogen (0.63%). Long-term (3.6 years) foliage decomposition rates were best correlated with initial lignin/N (r2 = 0.94, p r2 = 0.92, p r2 = 0.80, p < 0.05). Patterns of nutrient release were highly variable. Giant sequoia immobilized N and P, incense cedar immobilized N and to a lesser extent P, while sugar pine immobilized Ca. Strong linear or negative exponential relationships existed between initial concentrations of N, P, K, and Ca and percent original mass remaining of those nutrients after 3.6 years. This suggests efficient retention of these nutrients in the litter layer of these ecosystems. Nitrogen concentrations steadily increase in decomposing leaf litter, effectively reducing the C/N ratios from an initial range of 68–96 to 27–45 after 3.6 years.
Forest Gaps Alter the Total Phenol Dynamics in Decomposing Litter in an Alpine Fir Forest.
Li, Han; Xu, Liya; Wu, Fuzhong; Yang, Wanqin; Ni, Xiangyin; He, Jie; Tan, Bo; Hu, Yi
2016-01-01
The total phenol content in decomposing litter not only acts as a crucial litter quality indicator, but is also closely related to litter humification due to its tight absorption to clay particles. However, limited attention has been focused on the total phenol dynamics in foliar litter in relation to forest gaps. Here, the foliar litter of six representative tree species was incubated on the forest floor from the gap center to the closed canopy of an alpine Minjiang fir (Abies faxoniana) forest in the upper reaches of the Yangtze River and eastern Tibetan Plateau. The dynamics of total phenol concentration in the incubated litter was measured from November 2012 to October 2014. Over two-year incubation, 78.22% to 94.06% of total phenols were lost from the foliar litter, but 52.08% to 86.41% of this occurred in the first year. Forest gaps accelerated the loss of total phenols in the foliar litter in the winter, although they inhibited the loss of total phenols during the growing season in the first year. In comparison with the effects of forest gaps, the variations of litter quality among different species were much stronger on the dynamics of total phenols in the second year. Overall, the loss of total phenols in the foliar litter was slightly higher in both the canopy gap and the expanded gap than in the gap center and under the closed canopy. The results suggest that the predicted decline in snow cover resulting from winter warming or vanishing gaps caused by forest regeneration will retard the loss of total phenol content in the foliar litter of alpine forest ecosystems, especially in the first decomposition year.
Mendes-Soares, Helena; Velicer, Gregory J
2013-02-01
Predator-prey interactions presumably play major roles in shaping the composition and dynamics of microbial communities. However, little is understood about the population biology of such interactions or how predation-related parameters vary or correlate across prey environments. Myxococcus xanthus is a motile soil bacterium that feeds on a broad range of other soil microbes that vary greatly in the degree to which they support M. xanthus growth. In order to decompose predator-prey interactions at the population level, we quantified five predation-related parameters during M. xanthus growth on nine phylogenetically diverse bacterial prey species. The horizontal expansion rate of swarming predator colonies fueled by prey lawns served as our measure of overall predatory performance, as it incorporates both the searching (motility) and handling (killing and consumption of prey) components of predation. Four other parameters-predator population growth rate, maximum predator yield, maximum prey kill, and overall rate of prey death-were measured from homogeneously mixed predator-prey lawns from which predator populations were not allowed to expand horizontally by swarming motility. All prey species fueled predator population growth. For some prey, predator-specific prey death was detected contemporaneously with predator population growth, whereas killing of other prey species was detected only after cessation of predator growth. All four of the alternative parameters were found to correlate significantly with predator swarm expansion rate to varying degrees, suggesting causal interrelationships among these diverse predation measures. More broadly, our results highlight the importance of examining multiple parameters for thoroughly understanding the population biology of microbial predation.
Forest Gaps Alter the Total Phenol Dynamics in Decomposing Litter in an Alpine Fir Forest
Li, Han; Xu, Liya; Wu, Fuzhong; Yang, Wanqin; Ni, Xiangyin; He, Jie; Tan, Bo; Hu, Yi
2016-01-01
The total phenol content in decomposing litter not only acts as a crucial litter quality indicator, but is also closely related to litter humification due to its tight absorption to clay particles. However, limited attention has been focused on the total phenol dynamics in foliar litter in relation to forest gaps. Here, the foliar litter of six representative tree species was incubated on the forest floor from the gap center to the closed canopy of an alpine Minjiang fir (Abies faxoniana) forest in the upper reaches of the Yangtze River and eastern Tibetan Plateau. The dynamics of total phenol concentration in the incubated litter was measured from November 2012 to October 2014. Over two-year incubation, 78.22% to 94.06% of total phenols were lost from the foliar litter, but 52.08% to 86.41% of this occurred in the first year. Forest gaps accelerated the loss of total phenols in the foliar litter in the winter, although they inhibited the loss of total phenols during the growing season in the first year. In comparison with the effects of forest gaps, the variations of litter quality among different species were much stronger on the dynamics of total phenols in the second year. Overall, the loss of total phenols in the foliar litter was slightly higher in both the canopy gap and the expanded gap than in the gap center and under the closed canopy. The results suggest that the predicted decline in snow cover resulting from winter warming or vanishing gaps caused by forest regeneration will retard the loss of total phenol content in the foliar litter of alpine forest ecosystems, especially in the first decomposition year. PMID:26849120
Functional and Structural Succession of Soil Microbial Communities below Decomposing Human Cadavers.
Cobaugh, Kelly L; Schaeffer, Sean M; DeBruyn, Jennifer M
2015-01-01
The ecological succession of microbes during cadaver decomposition has garnered interest in both basic and applied research contexts (e.g. community assembly and dynamics; forensic indicator of time since death). Yet current understanding of microbial ecology during decomposition is almost entirely based on plant litter. We know very little about microbes recycling carcass-derived organic matter despite the unique decomposition processes. Our objective was to quantify the taxonomic and functional succession of microbial populations in soils below decomposing cadavers, testing the hypotheses that a) periods of increased activity during decomposition are associated with particular taxa; and b) human-associated taxa are introduced to soils, but do not persist outside their host. We collected soils from beneath four cadavers throughout decomposition, and analyzed soil chemistry, microbial activity and bacterial community structure. As expected, decomposition resulted in pulses of soil C and nutrients (particularly ammonia) and stimulated microbial activity. There was no change in total bacterial abundances, however we observed distinct changes in both function and community composition. During active decay (7 - 12 days postmortem), respiration and biomass production rates were high: the community was dominated by Proteobacteria (increased from 15.0 to 26.1% relative abundance) and Firmicutes (increased from 1.0 to 29.0%), with reduced Acidobacteria abundances (decreased from 30.4 to 9.8%). Once decay rates slowed (10 - 23 d postmortem), respiration was elevated, but biomass production rates dropped dramatically; this community with low growth efficiency was dominated by Firmicutes (increased to 50.9%) and other anaerobic taxa. Human-associated bacteria, including the obligately anaerobic Bacteroides, were detected at high concentrations in soil throughout decomposition, up to 198 d postmortem. Our results revealed the pattern of functional and compositional succession
Clostridium algifaecis sp. nov., an anaerobic bacterial species from decomposing algal scum.
Wu, Yu-Fan; Zheng, Hui; Wu, Qing-Long; Yang, Hong; Liu, Shuang-Jiang
2014-11-01
Two anaerobic bacterial strains, MB9-7(T) and MB9-9, were isolated from decomposing algal scum and were characterized using a polyphasic approach. Phylogenetic analysis of 16S rRNA gene sequences showed that strains MB9-7(T) and MB9-9 are closely related to each other (99.7% similarity) and they are also closely related to Clostridium tyrobutyricum (96.5%). The two strains were Gram-stain positive and rod-shaped. Growth occurred at 20-45 °C, at pH 4.0-8.0 and at NaCl concentrations of up to 2% (w/v). Acid was produced from glucose, xylose and mannose. Products of fermentation in PYG medium were mainly butyrate, acetate, carbon dioxide and hydrogen. The predominant cellular fatty acids were C(14:0) and C(16:0). The cellular polar lipids comprised phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, two glycolipids, one phospholipid, one aminophospholipid and two aminolipids. The DNA G+C contents of strain MB9-7(T) and MB9-9 were 27.9 and 28.7 mol%, respectively. These results support the assignment of the new isolates to the genus Clostridium and also distinguish them from other species of the genus Clostridium. Hence, it is proposed that strains MB9-7(T) and MB9-9 represent a novel species of the genus Clostridium, with the suggested name Clostridium algifaecis sp. nov. The type strain is MB9-7(T) ( =CGMCC 1.5188(T) =DSM 28783(T)).
Forest Gaps Alter the Total Phenol Dynamics in Decomposing Litter in an Alpine Fir Forest.
Li, Han; Xu, Liya; Wu, Fuzhong; Yang, Wanqin; Ni, Xiangyin; He, Jie; Tan, Bo; Hu, Yi
2016-01-01
The total phenol content in decomposing litter not only acts as a crucial litter quality indicator, but is also closely related to litter humification due to its tight absorption to clay particles. However, limited attention has been focused on the total phenol dynamics in foliar litter in relation to forest gaps. Here, the foliar litter of six representative tree species was incubated on the forest floor from the gap center to the closed canopy of an alpine Minjiang fir (Abies faxoniana) forest in the upper reaches of the Yangtze River and eastern Tibetan Plateau. The dynamics of total phenol concentration in the incubated litter was measured from November 2012 to October 2014. Over two-year incubation, 78.22% to 94.06% of total phenols were lost from the foliar litter, but 52.08% to 86.41% of this occurred in the first year. Forest gaps accelerated the loss of total phenols in the foliar litter in the winter, although they inhibited the loss of total phenols during the growing season in the first year. In comparison with the effects of forest gaps, the variations of litter quality among different species were much stronger on the dynamics of total phenols in the second year. Overall, the loss of total phenols in the foliar litter was slightly higher in both the canopy gap and the expanded gap than in the gap center and under the closed canopy. The results suggest that the predicted decline in snow cover resulting from winter warming or vanishing gaps caused by forest regeneration will retard the loss of total phenol content in the foliar litter of alpine forest ecosystems, especially in the first decomposition year. PMID:26849120
Duarte, Sofia; Cássio, Fernanda; Ferreira, Verónica; Canhoto, Cristina; Pascoal, Cláudia
2016-08-01
Ongoing climate change is expected to affect the diversity and activity of aquatic microbes, which play a key role in plant litter decomposition in forest streams. We used a before-after control-impact (BACI) design to study the effects of warming on a forest stream reach. The stream reach was divided by a longitudinal barrier, and during 1 year (ambient year) both stream halves were at ambient temperature, while in the second year (warmed year) the temperature in one stream half was increased by ca. 3 °C above ambient temperature (experimental half). Fine-mesh bags containing oak (Quercus robur L.) leaves were immersed in both stream halves for up to 60 days in spring and autumn of the ambient and warmed years. We assessed leaf-associated microbial diversity by denaturing gradient gel electrophoresis and identification of fungal conidial morphotypes and microbial activity by quantifying leaf mass loss and productivity of fungi and bacteria. In the ambient year, no differences were found in leaf decomposition rates and microbial productivities either between seasons or stream halves. In the warmed year, phosphorus concentration in the stream water, leaf decomposition rates, and productivity of bacteria were higher in spring than in autumn. They did not differ between stream halves, except for leaf decomposition, which was higher in the experimental half in spring. Fungal and bacterial communities differed between seasons in both years. Seasonal changes in stream water variables had a greater impact on the activity and diversity of microbial decomposers than a warming regime simulating a predicted global warming scenario.
Functional and Structural Succession of Soil Microbial Communities below Decomposing Human Cadavers
Cobaugh, Kelly L.; Schaeffer, Sean M.; DeBruyn, Jennifer M.
2015-01-01
The ecological succession of microbes during cadaver decomposition has garnered interest in both basic and applied research contexts (e.g. community assembly and dynamics; forensic indicator of time since death). Yet current understanding of microbial ecology during decomposition is almost entirely based on plant litter. We know very little about microbes recycling carcass-derived organic matter despite the unique decomposition processes. Our objective was to quantify the taxonomic and functional succession of microbial populations in soils below decomposing cadavers, testing the hypotheses that a) periods of increased activity during decomposition are associated with particular taxa; and b) human-associated taxa are introduced to soils, but do not persist outside their host. We collected soils from beneath four cadavers throughout decomposition, and analyzed soil chemistry, microbial activity and bacterial community structure. As expected, decomposition resulted in pulses of soil C and nutrients (particularly ammonia) and stimulated microbial activity. There was no change in total bacterial abundances, however we observed distinct changes in both function and community composition. During active decay (7 - 12 days postmortem), respiration and biomass production rates were high: the community was dominated by Proteobacteria (increased from 15.0 to 26.1% relative abundance) and Firmicutes (increased from 1.0 to 29.0%), with reduced Acidobacteria abundances (decreased from 30.4 to 9.8%). Once decay rates slowed (10 - 23 d postmortem), respiration was elevated, but biomass production rates dropped dramatically; this community with low growth efficiency was dominated by Firmicutes (increased to 50.9%) and other anaerobic taxa. Human-associated bacteria, including the obligately anaerobic Bacteroides, were detected at high concentrations in soil throughout decomposition, up to 198 d postmortem. Our results revealed the pattern of functional and compositional succession
Bambini, Valentina; Gentili, Claudio; Ricciardi, Emiliano; Bertinetto, Pier Marco; Pietrini, Pietro
2011-10-10
Prior neuroimaging studies on metaphor comprehension have tended to focus on the role of the right hemisphere, without reaching consensus and leaving aside the functional architecture of this process. The present work aimed to break down metaphor comprehension into its functional components. The study rationale is two-fold: on the one hand, the large-scale network model as emerging in cognitive neuroscience led us to a consideration of metaphor as supported by a distributed and bilateral network; on the other hand, we based on the accounts of figurative language put forward in pragmatics and cognitive science to postulate a decomposition of such a network into multiple sub-systems. During scanning, participants implicitly processed metaphorical (familiar and unfamiliar) and non-metaphorical passages, while being explicitly involved in an adjective matching task to be performed after reading the target passages. Several regions showed greater activity to metaphors as compared to non-metaphors, including left and right inferior frontal gyrus, right superior temporal gyrus, left angular gyrus, and anterior cingulate. This pattern of activations, markedly bilateral, can be decomposed into circumscribed functional sub-systems mediating different aspects of metaphor resolution, as foreseen in the pragmatic and cognitive literature: (a) the conceptual/pragmatic machinery in the bilateral inferior frontal gyrus and in the left angular gyrus, which supports the integration of linguistic material and world knowledge in context; (b) the attentional component in the anterior cingulate and prefrontal areas, which is set to monitor and filter for the relevant aspects of context and for the appropriate meanings; (c) the Theory of Mind system along the right superior temporal sulcus, which deals with the recognition of speakers' communicative intentions and is more extensively activated by unfamiliar metaphors. The results have several implications for the field of neuropragmatics
Effect of alginic acid decomposing bacterium on the growth of Laminaria japonica (Phaeophyceae).
Wang, You; Tang, Xue-Xi; Yang, Zhen; Yu, Zhi-Ming
2006-01-01
We collected the diseased blades of Laminaria japonica from Yantai Sea Farm from October to December 2002, and the alginic acid decomposing bacterium on the diseased blade was isolated and purified, and was identified as Alteromonas espejiana. This bacterium was applied as the causative pathogen to infect the blades of L. japonica under laboratory conditions. The aim of the present study was to identify the effects of the bacterium on the growth of L. japonica, and to find the possibly effective mechanism. Results showed that: (1) The blades of L. japonica exhibited symptoms of lesion, bleaching and deterioration when infected by the bacterium, and their growth and photosynthesis were dramatically suppressed. At the same time, the reactive oxygen species (ROS) generation enhanced obviously, and the relative membrane permeability increased significantly. The contents of malonaldehyde (MDA) and free fatty acid in the microsomol membrane greatly elevated, but the phospholipid content decreased. Result suggested an obvious peroxidation and deesterrification in the blades of L. japonica when infected by the bacterium. (2) The simultaneous assay on the antioxidant enzyme activities demonstrated that superoxide dismutase (SOD) and catalase (CAT) increased greatly when infected by the bacterium, but glutathione peroxidase (Gpx) and ascorbate peroxidase (APX) did not exhibit active responses to the bacterium throughout the experiment. (3) The histomorphological observations gave a distinctive evidence of the severity of the lesions as well as the relative abundance in the bacterial population on the blades after infection. The bacterium firstly invaded into the endodermis of L. japonica and gathered around there, and then resulted in the membrane damage, cells corruption and ultimately, the death of L. japonica.
Takao, Yoshitake; Tomaru, Yuji; Nagasaki, Keizo; Honda, Daiske
2015-01-01
Thraustochytrids are cosmopolitan osmotrophic or heterotrophic microorganisms that are considered as important decomposers in coastal ecosystems. However, because of a lack of estimation method for each genus or systematic group of them, relatively little is known about their ecology in situ. Previously, we reported two distinct types of virus infecting thraustochytrids (AuRNAV: reported as SssRNAV, and SmDNAV) suggesting they have wide distributions in the host-virus systems of coastal environments. Here we conducted a field survey from 2004 through 2005 to show the fluctuation pattern of thraustochytrids and their viruses in Hiroshima Bay, Japan. During the field survey, we monitored the dynamics of the two types of thraustochytrid-infecting virus: small viruses causing lysis of Aurantiochytrium sp. NIBH N1-27 (identified as AuRNAV) and the large viruses of Sicyoidochytrium minutum NBRC 102975 (similar to SmDNAV in physiology and morphology). Fluctuation patterns of the two distinct types of virus were different from each other. This may reflect the difference in the preference of organic substrates; i.e., it may be likely the host of AuRNAV (Aurantiochytrium sp.) increases utilizing algal dead bodies or feeble cells as the virus shows a large increase in abundance following raphidophyte blooms; whereas, the trophic nutrient supply for S. minutum may primarily depend on other constantly-supplied organic compounds because it did not show any significant change in abundance throughout the survey. Further study concerning the population composition of thraustochytrids and their viruses may demonstrate the microbial ecology (especially concerning the detrital food web) of marine environments. PMID:26203654
NASA Astrophysics Data System (ADS)
Zwart, Christine M.; Venkatesan, Ragav; Frakes, David H.
2012-10-01
Interpolation is an essential and broadly employed function of signal processing. Accordingly, considerable development has focused on advancing interpolation algorithms toward optimal accuracy. Such development has motivated a clear shift in the state-of-the art from classical interpolation to more intelligent and resourceful approaches, registration-based interpolation for example. As a natural result, many of the most accurate current algorithms are highly complex, specific, and computationally demanding. However, the diverse hardware destinations for interpolation algorithms present unique constraints that often preclude use of the most accurate available options. For example, while computationally demanding interpolators may be suitable for highly equipped image processing platforms (e.g., computer workstations and clusters), only more efficient interpolators may be practical for less well equipped platforms (e.g., smartphones and tablet computers). The latter examples of consumer electronics present a design tradeoff in this regard: high accuracy interpolation benefits the consumer experience but computing capabilities are limited. It follows that interpolators with favorable combinations of accuracy and efficiency are of great practical value to the consumer electronics industry. We address multidimensional interpolation-based image processing problems that are common to consumer electronic devices through a decomposition approach. The multidimensional problems are first broken down into multiple, independent, one-dimensional (1-D) interpolation steps that are then executed with a newly modified registration-based one-dimensional control grid interpolator. The proposed approach, decomposed multidimensional control grid interpolation (DMCGI), combines the accuracy of registration-based interpolation with the simplicity, flexibility, and computational efficiency of a 1-D interpolation framework. Results demonstrate that DMCGI provides improved interpolation
NASA Astrophysics Data System (ADS)
Fockedey, N.; Mees, J.
1999-10-01
The diet of the mysid Neomysis integer in the maximum turbidity zone (MTZ) of three European estuaries (Elbe, Westerschelde and Gironde) was investigated in spring 1993. The quality and quantity of the diet were assessed through measurement of the stomach fullness and microscopical analysis of the stomach content combined with image analyses. N. integer was found to be an omnivore which mainly utilizes mesozooplankton and detritus carbon pools. The quality of the diet did not differ between the sexes or between different developmental stages, although smaller individuals consumed fewer items. In all three estuaries the diet was dominated by Copepoda Calanoida (5-10 Eurytemora affinis ind -1 for adults; 2-5 ind -1 and 2-3 ind -1 for subadults and juveniles, respectively) and was supplemented with Rotifera and Cladocera. Phytoplankton and benthic organisms, though present in the stomachs, were negligible. Macrophytal detritus and amorphous material, the latter unidentifiable under the light microscope, were very abundant food items. The amorphous detritus was found to originate from the suspended sediment flocs which are characteristic for the MTZ and mainly consist of clay minerals. The energetic value of the flocs for N. integer remains unclear.
NASA Astrophysics Data System (ADS)
Dubois, J.; Jullien, T.; Grenier, C.; Degiovanni, P.; Roulleau, P.; Glattli, D. C.
2013-08-01
We study the injection n of electrons in a quantum conductor using voltage pulses applied on a contact. We particularly consider the case of Lorentzian voltage pulses. When carrying integer charge, they are known to provide electronic states with a minimal number of excitations, while any other type of pulses are accompanied with a neutral cloud of electron and hole excitations. We focus on the low-frequency shot noise arising when the excitations are partitioned by a single scatterer. Using periodic pulses, the physics can be discussed in the framework of the photon-assisted shot noise. Pulses of arbitrary shape and arbitrary charge are shown to give a marked minimum in the noise when the charge is an integer. The energy-domain characterization of the charge pulse excitations is also given using the shot-noise spectroscopy which reveals the asymmetrical energy spectrum of Lorentzian pulses. Finally, time-domain information is obtained from Hong-Ou-Mandel-type noise correlations when two trains of pulses generated on opposite contacts collide on the scatterer. For integer Lorentzian, the noise versus the time delay between pulse trains is shown to give a measure of the electron wave-packet autocorrelation function. In order to make contact with recent experiments, all the calculations are made at zero and finite temperatures.
Fanin, Nicolas; Hättenschwiler, Stephan; Chavez Soria, Paola F; Fromin, Nathalie
2015-01-01
Nitrogen (N) and phosphorus (P) availability both control microbial decomposers and litter decomposition. However, these two key nutrients show distinct release patterns from decomposing litter and are unlikely available at the same time in most ecosystems. Little is known about how temporal differences in N and P availability affect decomposers and litter decomposition, which may be particularly critical for tropical rainforests growing on old and nutrient-impoverished soils. Here we used three chemically contrasted leaf litter substrates and cellulose paper as a widely accessible substrate containing no nutrients to test the effects of temporal differences in N and P availability in a microcosm experiment under fully controlled conditions. We measured substrate mass loss, microbial activity (by substrate induced respiration, SIR) as well as microbial community structure (using phospholipid fatty acids, PLFAs) in the litter and the underlying soil throughout the initial stages of decomposition. We generally found a stronger stimulation of substrate mass loss and microbial respiration, especially for cellulose, with simultaneous NP addition compared to a temporally separated N and P addition. However, litter types with a relatively high N to P availability responded more to initial P than N addition and vice versa. A third litter species showed no response to fertilization regardless of the sequence of addition, likely due to strong C limitation. Microbial community structure in the litter was strongly influenced by the fertilization sequence. In particular, the fungi to bacteria ratio increased following N addition alone, a shift that was reversed with complementary P addition. Opposite to the litter layer microorganisms, the soil microbial community structure was more strongly influenced by the identity of the decomposing substrate than by fertilization treatments, reinforcing the idea that C availability can strongly constrain decomposer communities
Barner, David; Chow, Katherine; Yang, Shu-Ju
2009-03-01
We explored children's early interpretation of numerals and linguistic number marking, in order to test the hypothesis (e.g., Carey (2004). Bootstrapping and the origin of concepts. Daedalus, 59-68) that children's initial distinction between one and other numerals (i.e., two, three, etc.) is bootstrapped from a prior distinction between singular and plural nouns. Previous studies have presented evidence that in languages without singular-plural morphology, like Japanese and Chinese, children acquire the meaning of the word one later than in singular-plural languages like English and Russian. In two experiments, we sought to corroborate this relation between grammatical number and integer acquisition within English. We found a significant correlation between children's comprehension of numerals and a large set of natural language quantifiers and determiners, even when controlling for effects due to age. However, we also found that 2-year-old children, who are just acquiring singular-plural morphology and the word one, fail to assign an exact interpretation to singular noun phrases (e.g., a banana), despite interpreting one as exact. For example, in a Truth-Value Judgment task, most children judged that a banana was consistent with a set of two objects, despite rejecting sets of two for the numeral one. Also, children who gave exactly one object for singular nouns did not have a better comprehension of numerals relative to children who did not give exactly one. Thus, we conclude that the correlation between quantifier comprehension and numeral comprehension in children of this age is not attributable to the singular-plural distinction facilitating the acquisition of the word one. We argue that quantifiers play a more general role in highlighting the semantic function of numerals, and that children distinguish between numerals and other quantifiers from the beginning, assigning exact interpretations only to numerals. PMID:18799157
ERIC Educational Resources Information Center
Cieslicka, Anna B.
2013-01-01
The purpose of this study was to explore possible cerebral asymmetries in the processing of decomposable and nondecomposable idioms by fluent nonnative speakers of English. In the study, native language (Polish) and foreign language (English) decomposable and nondecomposable idioms were embedded in ambiguous (neutral) and unambiguous (biasing…
Converted-waves Imaging Condition for Elastic Reverse-Time Migration with Decomposed Wavefields
NASA Astrophysics Data System (ADS)
Kim, B.; Choi, H.; Seol, S. J.; Byun, J.
2015-12-01
To successfully deal with responses from the elastic earth, imaging techniques need to incorporate the elastic wave equation. Elastic Reverse-Time Migration (ERTM) with separating-while-imaging approach is capable of yielding physically meaningful PP, PS, SP, and SS images from multicomponent data. Even in PP images, ERTM has brought enhancements comparing to those from acoustic RTM because ERTM can handle converted waves. Converted-wave images, core results of ERTM, however, have two major problems related to characteristics of S-waves. First, polarity reversals according to propagation directions of S-waves cause destructive effect to final PS and SP images while each migrated result is stacked over the shots. In addition, non-existent spurious events which are produced by crosscorrelating downgoing S-waves in source wavefields and reflections associated with downgoing P-waves in receiver wavefields lead masking effects over true reflection events in SP and SS images. In this study, we adopt a wavefield decomposition method to solve the polarity problems and derive a new converted-wave imaging condition for SP and SS images to alleviate the generation of spurious events. The acceleration vector wavefield decomposition method used in our ERTM has advantages over the conventional wavefield separation method based on the Helmholtz decomposition because the wavefield decomposition can automatically compensate polarity changes in PS and SP images when the zero-lag crosscorrelation for vector wavefields is applied. To suppress spurious events in SP and SS images, our imaging condition is designed to make images only where S- and converted P-waves from source wavefields are coexisted with decomposed wavefields from receiver wavefields at reflection boundaries. To verify our new imaging condition, we tested our algorithm with OBC (Ocean Bottom Cable) data from elastic Marmousi-II model and compared the migrated images with those from ERTM with the zero
Gervasi, Vincenzo; Sand, Hakan; Zimmermann, Barbara; Mattisson, Jenny; Wabakken, Petter; Linnell, John D C
2013-10-01
Recolonizing carnivores can have a large impact on the status of wild ungulates, which have often modified their behavior in the absence of predation. Therefore, understanding the dynamics of reestablished predator-prey systems is crucial to predict their potential ecosystem effects. We decomposed the spatial structure of predation by recolonizing wolves (Canis lupus) on two sympatric ungulates, moose (Alces alces) and roe deer (Capreolus capreolus), in Scandinavia during a 10-year study. We monitored 18 wolves with GPS collars, distributed over 12 territories, and collected records from predation events. By using conditional logistic regression, we assessed the contributions of three main factors, the utilization patterns of each wolf territory, the spatial distribution of both prey species, and fine-scale landscape structure, in determining the spatial structure of moose and roe deer predation risk. The reestablished predator-prey system showed a remarkable spatial variation in kill occurrence at the intra-territorial level, with kill probabilities varying by several orders of magnitude inside the same territory. Variation in predation risk was evident also when a spatially homogeneous probability for a wolf to encounter a prey was simulated. Even inside the same territory, with the same landscape structure, and when exposed to predation by the same wolves, the two prey species experienced an opposite spatial distribution of predation risk. In particular, increased predation risk for moose was associated with open areas, especially clearcuts and young forest stands, whereas risk was lowered for roe deer in the same habitat types. Thus, fine-scale landscape structure can generate contrasting predation risk patterns in sympatric ungulates, so that they can experience large differences in the spatial distribution of risk and refuge areas when exposed to predation by a recolonizing predator. Territories with an earlier recolonization were not associated with a lower
Gervasi, Vincenzo; Sand, Hakan; Zimmermann, Barbara; Mattisson, Jenny; Wabakken, Petter; Linnell, John D C
2013-10-01
Recolonizing carnivores can have a large impact on the status of wild ungulates, which have often modified their behavior in the absence of predation. Therefore, understanding the dynamics of reestablished predator-prey systems is crucial to predict their potential ecosystem effects. We decomposed the spatial structure of predation by recolonizing wolves (Canis lupus) on two sympatric ungulates, moose (Alces alces) and roe deer (Capreolus capreolus), in Scandinavia during a 10-year study. We monitored 18 wolves with GPS collars, distributed over 12 territories, and collected records from predation events. By using conditional logistic regression, we assessed the contributions of three main factors, the utilization patterns of each wolf territory, the spatial distribution of both prey species, and fine-scale landscape structure, in determining the spatial structure of moose and roe deer predation risk. The reestablished predator-prey system showed a remarkable spatial variation in kill occurrence at the intra-territorial level, with kill probabilities varying by several orders of magnitude inside the same territory. Variation in predation risk was evident also when a spatially homogeneous probability for a wolf to encounter a prey was simulated. Even inside the same territory, with the same landscape structure, and when exposed to predation by the same wolves, the two prey species experienced an opposite spatial distribution of predation risk. In particular, increased predation risk for moose was associated with open areas, especially clearcuts and young forest stands, whereas risk was lowered for roe deer in the same habitat types. Thus, fine-scale landscape structure can generate contrasting predation risk patterns in sympatric ungulates, so that they can experience large differences in the spatial distribution of risk and refuge areas when exposed to predation by a recolonizing predator. Territories with an earlier recolonization were not associated with a lower
Sugama T.; Pyatina, T.; Gill, S.; Kisslinger, K.; Iverson, B.; Bour, D.
2012-11-01
potential as a self-decomposable bridging additive in the SSASC cement sealer.
Modelling the dissipation and leaching of two herbicides in decomposing mulch of crop residues
NASA Astrophysics Data System (ADS)
Aslam, Sohaib; Iqbal, Akhtar; Lafolie, François; Recous, Sylvie; Benoit, Pierre; Garnier, Patricia
2013-04-01
greater leaching from mulch than S-metolachlor because of its lower adsorption coefficients to organic mulch. Moreover, simulated results showed a much faster degradation of glyphosate but greater non-extractable residue formation for S-metolachlor. Keywords: Mulch; Pesticides; Transport; Degradation; Modeling; Pastis-mulch References Findeling, A., Garnier, P., Coppens, F., Lafolie, F., Recous, S., 2007. Modelling water, carbon and nitrogen dynamics in soil covered with decomposing mulch. European Journal of Soil Science 58, 196-206. Lashermes, G., Zhang, Y., Houot, S., Barriuso, E., Steyer, J.P., Patureau, D., Garnier, P., 2013. A model coupling organic carbon and organic pollutant dynamics during composting. Journal of Environmental Quality. In Press.
Relating soil pore geometry to soil water content dynamics decomposed at multiple frequencies
NASA Astrophysics Data System (ADS)
Qin, Mingming; Gimenez, Daniel; Cooper, Miguel
2016-04-01
Soil structure is a critical factor determining the response of soil water content to meteorological inputs such as precipitation. Wavelet analysis can be used to filter a signal into several wavelet components, each characterizing a given frequency. The purpose of this research was to investigate relationships between the geometry of soil pore systems and the various wavelet components derived from soil water content dynamics. The two study sites investigated were located in the state of São Paulo, Brazil. Each site was comprised of five soil profiles, the first site was situated along a 300-meter transect with about 10% slope in a tropical semi-deciduous forest, while the second one spanned 230-meter over a Brazilian savanna with a slope of about 6%. For each profile, between two to four Water Content Reflectometer CS615 (Campbell Scientific, Inc.) probes were installed according to horizonation at depths varying between 0.1 m and 2.3 m. Bulk soil, three soil cores, and one undisturbed soil block were sampled from selected horizons for determining particle size distributions, water retention curves, and pore geometry, respectively. Pore shape and size were determined from binary images obtained from resin-impregnated blocks and used to characterize pore geometry. Soil water contents were recorded at a 20-minute interval over a 4-month period. The Mexican hat wavelet was used to decompose soil water content measurements into wavelet components. The responses of wavelet components to wetting and drying cycles were characterized by the median height of the peaks in each wavelet component and were correlated with particular pore shapes and sizes. For instance, large elongated and irregular pores, largely responsible for the transmission of water, were significantly correlated with wavelet components at high frequencies (40 minutes to 48 hours) while rounded pores, typically associated to water retention, were only significantly correlated to lower frequency ranges
Kim, Youngwoo; Woo, Kyoohee; Kim, Inhyuk; Cho, Yong Soo; Jeong, Sunho; Moon, Jooho
2013-11-01
Among various candidate materials, Cu2ZnSnS4 (CZTS) is a promising earth-abundant semiconductor for low-cost thin film solar cells. We report a facile, less toxic, highly concentrated synthetic method utilizing the heretofore unrecognized, easily decomposable capping ligand of triphenylphosphate, where phase-pure, single-crystalline, and well-dispersed colloidal CZTS nanocrystals were obtained. The favorable influence of the easily decomposable capping ligand on the microstructural evolution of device-quality CZTS absorber layers was clarified based on a comparative study with commonly used oleylamine-capped CZTS nanoparticles. The resulting CZTS nanoparticles enabled us to produce a dense and crack-free absorbing layer through annealing under a N2 + H2S (4%) atmosphere, demonstrating a solar cell with an efficiency of 3.6% under AM 1.5 illumination.
Kaiser, Christina; Franklin, Oskar; Richter, Andreas; Dieckmann, Ulf
2015-01-01
The chemical structure of organic matter has been shown to be only marginally important for its decomposability by microorganisms. The question of why organic matter does accumulate in the face of powerful microbial degraders is thus key for understanding terrestrial carbon and nitrogen cycling. Here we demonstrate, based on an individual-based microbial community model, that social dynamics among microbes producing extracellular enzymes ('decomposers') and microbes exploiting the catalytic activities of others ('cheaters') regulate organic matter turnover. We show that the presence of cheaters increases nitrogen retention and organic matter build-up by downregulating the ratio of extracellular enzymes to total microbial biomass, allowing nitrogen-rich microbial necromass to accumulate. Moreover, increasing catalytic efficiencies of enzymes are outbalanced by a strong negative feedback on enzyme producers, leading to less enzymes being produced at the community level. Our results thus reveal a possible control mechanism that may buffer soil CO2 emissions in a future climate.
NASA Astrophysics Data System (ADS)
Podgórska, B.; Mudryk, Z. J.
2003-03-01
The potential capability to decompose macromolecular compounds, and the level of extracellular enzyme activities were determined in heterotrophic bacteria isolated from a sandy beach in Sopot on the Southern Baltic Sea coast. Individual isolates were capable of hydrolysing a wide spectrum of organic macromolecular compounds. Lipids, gelatine, and DNA were hydrolyzed most efficiently. Only a very small percentage of strains were able to decompose cellulose, and no pectinolytic bacteria were found. Except for starch-hydrolysis, no significant differences in the intensity of organic compound decomposition were recorded between horizontal and vertical profiles of the studied beach. Of all the studied extracellular enzymes, alkaline phosphatase, esterase lipase, and leucine acrylaminidase were most active; in contrast, the activity α-fucosidase, α-galactosidase and β-glucouronidase was the weakest. The level of extracellular enzyme activity was similar in both sand layers.
NASA Technical Reports Server (NTRS)
Leutenegger, Scott T.; Horton, Graham
1994-01-01
Recently the Multi-Level algorithm was introduced as a general purpose solver for the solution of steady state Markov chains. In this paper, we consider the performance of the Multi-Level algorithm for solving Nearly Completely Decomposable (NCD) Markov chains, for which special-purpose iteractive aggregation/disaggregation algorithms such as the Koury-McAllister-Stewart (KMS) method have been developed that can exploit the decomposability of the the Markov chain. We present experimental results indicating that the general-purpose Multi-Level algorithm is competitive, and can be significantly faster than the special-purpose KMS algorithm when Gauss-Seidel and Gaussian Elimination are used for solving the individual blocks.
CUMBIN - CUMULATIVE BINOMIAL PROGRAMS
NASA Technical Reports Server (NTRS)
Bowerman, P. N.
1994-01-01
The cumulative binomial program, CUMBIN, is one of a set of three programs which calculate cumulative binomial probability distributions for arbitrary inputs. The three programs, CUMBIN, NEWTONP (NPO-17556), and CROSSER (NPO-17557), can be used independently of one another. CUMBIN can be used by statisticians and users of statistical procedures, test planners, designers, and numerical analysts. The program has been used for reliability/availability calculations. CUMBIN calculates the probability that a system of n components has at least k operating if the probability that any one operating is p and the components are independent. Equivalently, this is the reliability of a k-out-of-n system having independent components with common reliability p. CUMBIN can evaluate the incomplete beta distribution for two positive integer arguments. CUMBIN can also evaluate the cumulative F distribution and the negative binomial distribution, and can determine the sample size in a test design. CUMBIN is designed to work well with all integer values 0 < k <= n. To run the program, the user simply runs the executable version and inputs the information requested by the program. The program is not designed to weed out incorrect inputs, so the user must take care to make sure the inputs are correct. Once all input has been entered, the program calculates and lists the result. The CUMBIN program is written in C. It was developed on an IBM AT with a numeric co-processor using Microsoft C 5.0. Because the source code is written using standard C structures and functions, it should compile correctly with most C compilers. The program format is interactive. It has been implemented under DOS 3.2 and has a memory requirement of 26K. CUMBIN was developed in 1988.
Zhu, Huike; Zhong, Huan; Fu, Fangjing; Zeng, Zhen
2015-08-01
Recently, incorporation of crop straw into soils is being largely encouraged worldwide. To explore the possible influence of incorporation of decomposed crop straw on the speciation (i.e., inorganic mercury/IHg, and methylmercury/MMHg) and phytoavailability of mercury, mercury-contaminated farming soil was amended with different amounts (i.e., low, medium or high) of straw organic fertilizer (SF, mainly consisting of decomposed rice straw) or humus (HU) and incubated for a month. Potential phytoavailability of IHg, assessed by CaCl2 extraction, was significantly lower in soils amended with low/medium SF, possibly due to the immobilization effect of SF-organic matter on IHg. In contrast, phytoavailability of IHg was significantly higher in soils incorporated with high HU, possibly explained by the leaching effect of dissolved HU on soil-bound IHg. For MMHg, incorporation of medium/high HU significantly increased MMHg phytoavailability, while SF addition had little effect. Interestingly, MMHg levels in SF/HU amended soils were generally lower than that in soil receiving no amendment, probably because complexation of IHg with SF/HU organics decreased IHg availability to methylation microorganisms. Overall, current results suggested that incorporation of decomposed crop straw may have multiple effects on mercury biogeochemistry in soils, which should be considered when applying SF into mercury-contaminated farming soils. PMID:25855528
Zhu, Huike; Zhong, Huan; Fu, Fangjing; Zeng, Zhen
2015-08-01
Recently, incorporation of crop straw into soils is being largely encouraged worldwide. To explore the possible influence of incorporation of decomposed crop straw on the speciation (i.e., inorganic mercury/IHg, and methylmercury/MMHg) and phytoavailability of mercury, mercury-contaminated farming soil was amended with different amounts (i.e., low, medium or high) of straw organic fertilizer (SF, mainly consisting of decomposed rice straw) or humus (HU) and incubated for a month. Potential phytoavailability of IHg, assessed by CaCl2 extraction, was significantly lower in soils amended with low/medium SF, possibly due to the immobilization effect of SF-organic matter on IHg. In contrast, phytoavailability of IHg was significantly higher in soils incorporated with high HU, possibly explained by the leaching effect of dissolved HU on soil-bound IHg. For MMHg, incorporation of medium/high HU significantly increased MMHg phytoavailability, while SF addition had little effect. Interestingly, MMHg levels in SF/HU amended soils were generally lower than that in soil receiving no amendment, probably because complexation of IHg with SF/HU organics decreased IHg availability to methylation microorganisms. Overall, current results suggested that incorporation of decomposed crop straw may have multiple effects on mercury biogeochemistry in soils, which should be considered when applying SF into mercury-contaminated farming soils.
Chryseobacterium artocarpi sp. nov., isolated from the rhizosphere soil of Artocarpus integer.
Venil, Chidambaram Kulandaisamy; Nordin, Nordiana; Zakaria, Zainul Akmar; Ahmad, Wan Azlina
2014-09-01
A bacterial strain, designated UTM-3(T), isolated from the rhizosphere soil of Artocarpus integer (cempedak) in Malaysia was studied to determine its taxonomic position. Cells were Gram-stain-negative, non-spore-forming rods, devoid of flagella and gliding motility, that formed yellow-pigmented colonies on nutrient agar and contained MK-6 as the predominant menaquinone. Comparative analysis of the 16S rRNA gene sequence of strain UTM-3(T) with those of the most closely related species showed that the strain constituted a distinct phyletic line within the genus Chryseobacterium with the highest sequence similarities to Chryseobacterium lactis NCTC 11390(T), Chryseobacterium viscerum 687B-08(T), Chryseobacterium tructae 1084-08(T), Chryseobacterium arthrosphaerae CC-VM-7(T), Chryseobacterium oncorhynchi 701B-08(T), Chryseobacterium vietnamense GIMN1.005(T), Chryseobacterium bernardetii NCTC 13530(T), Chryseobacterium nakagawai NCTC 13529(T), Chryseobacterium gallinarum LMG 27808(T), Chryseobacterium culicis R4-1A(T), Chryseobacterium flavum CW-E2(T), Chryseobacterium aquifrigidense CW9(T), Chryseobacterium ureilyticum CCUG 52546(T), Chryseobacterium indologenes NBRC 14944(T), Chryseobacterium gleum CCUG 14555(T), Chryseobacterium jejuense JS17-8(T), Chryseobacterium oranimense H8(T) and Chryseobacterium joostei LMG 18212(T). The major whole-cell fatty acids were iso-C15 : 0 and iso-C17 : 1ω9c, followed by summed feature 4 (iso-C15 : 0 2-OH and/or C16 : 1ω7t) and iso-C17 : 0 3-OH, and the polar lipid profile consisted of phosphatidylethanolamine and several unknown lipids. The DNA G+C content strain UTM-3(T) was 34.8 mol%. On the basis of the phenotypic and phylogenetic evidence, it is concluded that the isolate represents a novel species of the genus Chryseobacterium, for which the name Chryseobacterium artocarpi sp. nov. is proposed. The type strain is UTM-3(T) ( = CECT 8497(T) = KCTC 32509(T)).
Chryseobacterium artocarpi sp. nov., isolated from the rhizosphere soil of Artocarpus integer.
Venil, Chidambaram Kulandaisamy; Nordin, Nordiana; Zakaria, Zainul Akmar; Ahmad, Wan Azlina
2014-09-01
A bacterial strain, designated UTM-3(T), isolated from the rhizosphere soil of Artocarpus integer (cempedak) in Malaysia was studied to determine its taxonomic position. Cells were Gram-stain-negative, non-spore-forming rods, devoid of flagella and gliding motility, that formed yellow-pigmented colonies on nutrient agar and contained MK-6 as the predominant menaquinone. Comparative analysis of the 16S rRNA gene sequence of strain UTM-3(T) with those of the most closely related species showed that the strain constituted a distinct phyletic line within the genus Chryseobacterium with the highest sequence similarities to Chryseobacterium lactis NCTC 11390(T), Chryseobacterium viscerum 687B-08(T), Chryseobacterium tructae 1084-08(T), Chryseobacterium arthrosphaerae CC-VM-7(T), Chryseobacterium oncorhynchi 701B-08(T), Chryseobacterium vietnamense GIMN1.005(T), Chryseobacterium bernardetii NCTC 13530(T), Chryseobacterium nakagawai NCTC 13529(T), Chryseobacterium gallinarum LMG 27808(T), Chryseobacterium culicis R4-1A(T), Chryseobacterium flavum CW-E2(T), Chryseobacterium aquifrigidense CW9(T), Chryseobacterium ureilyticum CCUG 52546(T), Chryseobacterium indologenes NBRC 14944(T), Chryseobacterium gleum CCUG 14555(T), Chryseobacterium jejuense JS17-8(T), Chryseobacterium oranimense H8(T) and Chryseobacterium joostei LMG 18212(T). The major whole-cell fatty acids were iso-C15 : 0 and iso-C17 : 1ω9c, followed by summed feature 4 (iso-C15 : 0 2-OH and/or C16 : 1ω7t) and iso-C17 : 0 3-OH, and the polar lipid profile consisted of phosphatidylethanolamine and several unknown lipids. The DNA G+C content strain UTM-3(T) was 34.8 mol%. On the basis of the phenotypic and phylogenetic evidence, it is concluded that the isolate represents a novel species of the genus Chryseobacterium, for which the name Chryseobacterium artocarpi sp. nov. is proposed. The type strain is UTM-3(T) ( = CECT 8497(T) = KCTC 32509(T)). PMID:24958763
Energy-Efficient Wide Datapath Integer Arithmetic Logic Units Using Superconductor Logic
NASA Astrophysics Data System (ADS)
Ayala, Christopher Lawrence
Complementary Metal-Oxide-Semiconductor (CMOS) technology is currently the most widely used integrated circuit technology today. As CMOS approaches the physical limitations of scaling, it is unclear whether or not it can provide long-term support for niche areas such as high-performance computing and telecommunication infrastructure, particularly with the emergence of cloud computing. Alternatively, superconductor technologies based on Josephson junction (JJ) switching elements such as Rapid Single Flux Quantum (RSFQ) logic and especially its new variant, Energy-Efficient Rapid Single Flux Quantum (ERSFQ) logic have the capability to provide an ultra-high-speed, low power platform for digital systems. The objective of this research is to design and evaluate energy-efficient, high-speed 32-bit integer Arithmetic Logic Units (ALUs) implemented using RSFQ and ERSFQ logic as the first steps towards achieving practical Very-Large-Scale-Integration (VLSI) complexity in digital superconductor electronics. First, a tunable VHDL superconductor cell library is created to provide a mechanism to conduct design exploration and evaluation of superconductor digital circuits from the perspectives of functionality, complexity, performance, and energy-efficiency. Second, hybrid wave-pipelining techniques developed earlier for wide datapath RSFQ designs have been used for efficient arithmetic and logic circuit implementations. To develop the core foundation of the ALU, the ripple-carry adder and the Kogge-Stone parallel prefix carry look-ahead adder are studied as representative candidates on opposite ends of the design spectrum. By combining the high-performance features of the Kogge-Stone structure and the low complexity of the ripple-carry adder, a 32-bit asynchronous wave-pipelined hybrid sparse-tree ALU has been designed and evaluated using the VHDL cell library tuned to HYPRES' gate-level characteristics. The designs and techniques from this research have been implemented using
A Bose-Einstein approach to the random partitioning of an integer
NASA Astrophysics Data System (ADS)
Huillet, Thierry E.
2011-08-01
Consider N equally spaced points on a circle of circumference N. Pick at random n points out of N on this circle and consider the discrete random spacings between consecutive sampled points, turning clockwise. This defines in the first place a random partitioning of N into n positive summands. Append then clockwise an arc of integral length k to each such sampled point, ending up with a discrete random set on the circle. Questions such as the evaluation of the probability of random covering or parking configurations, number and length of the gaps are addressed. For each value of k, asymptotic results are presented when n, N both go to \\infty according to two different regimes. In the first thermodynamical regime n/N\\rightarrow \\rho , the occurrence of, say, covering and parking configurations is exponentially rare in the whole admissible range of density ρ. We compute the rates from the equations of state. In the second one, they are macroscopically frequent. These questions require some understanding of both the smallest and largest extreme summands in the partition of N. We consider next an urn model where N indistinguishable balls are assigned at random into N distinguishable boxes. This urn model consists of a random partitioning model of integer N into N non-negative summands. Given there are n non-empty boxes this gives back the original partitioning model of N into n positive parts. Following this circle of ideas, a grand canonical balls in boxes approach is supplied, giving some insight into the multiplicities of the box occupancies. The random set model defines a k-nearest neighbor random graph with N vertices and kn edges. We shall also briefly consider the covering problem in the context of a random graph model with N vertices and n (out-degree 1) edges whose endpoints are no longer bound to be neighbors. In the latter setup, connectivity is increased in that there exists a critical density ρc above which covering occurs with probability 1.
NASA Astrophysics Data System (ADS)
Vesterdal, Lars; Masudur Rahman, Md.; Gomez de la Bárcena, Teresa
2014-05-01
Previous studies of environmental impact of cropland afforestation in a long-term experiment at Vestskoven, Denmark focused on changes in SOC stocks. Chronosequence and repeated sampling approaches revealed that soils initially lost C but started to gain C after about three decades. Soil carbon stocks represent the balance between litter input and heterotrophic respiration, and we hypothesized that heterotrophic respiration and in particular the decomposability of the organic matter would decrease with time after afforestation of cropland. The objective of this study was to assess the heterotrophic respiration (RH) and decomposability of SOC, i.e. the rate of respiration relative to content of SOM (RH/SOM), along chronosequences of Norway spruce (Picea abies (Karst.) L.) and oak (Quercus robur L.). The chronosequences included 15 stands aged 4-44 years and were supplemented by a permanent pasture (36 years), a cropland plot and a 200-year-old oak-dominated plantation for reference. Samples from top mineral soil (0-5 and 5-15 cm layers) were sampled by auger and incubated in a respirometer (Respicond VII) for three weeks at 15°C to assess potential RH and RH/SOM. Heterotrophic respiration (RH) in the 0-5 cm layer increased with time since afforestation in stands of both tree species while there was no change in decomposability of SOC (RH/SOM) with time or between tree species. In 5-15 cm, RH and RH/SOM were both unchanged after afforestation, but oak stands had significantly higher RH than Norway spruce in this layer and RH/SOM also tended to be higher. Cropland RH was low and comparable to that of the 4-year-old oak stand, whereas the 200-year-old plantation and the pasture generally had higher or similar RH rates compared to the older chronosequence stands. RH/SOM was comparable in cropland and afforested stands whereas RH/SOM was lower in the 200-year-old afforested stand. The increase in RH with age occurred concurrently with increases in SOC stock and C
NASA Technical Reports Server (NTRS)
Shaykhian, Gholam Ali
2007-01-01
The Java seminar covers the fundamentals of Java programming language. No prior programming experience is required for participation in the seminar. The first part of the seminar covers introductory concepts in Java programming including data types (integer, character, ..), operators, functions and constants, casts, input, output, control flow, scope, conditional statements, and arrays. Furthermore, introduction to Object-Oriented programming in Java, relationships between classes, using packages, constructors, private data and methods, final instance fields, static fields and methods, and overloading are explained. The second part of the seminar covers extending classes, inheritance hierarchies, polymorphism, dynamic binding, abstract classes, protected access. The seminar conclude by introducing interfaces, properties of interfaces, interfaces and abstract classes, interfaces and cailbacks, basics of event handling, user interface components with swing, applet basics, converting applications to applets, the applet HTML tags and attributes, exceptions and debugging.
A compact formulation for maximizing the expected number of transplants in kidney exchange programs
NASA Astrophysics Data System (ADS)
Alvelos, Filipe; Klimentova, Xenia; Rais, Abdur; Viana, Ana
2015-05-01
Kidney exchange programs (KEPs) allow the exchange of kidneys between incompatible donor-recipient pairs. Optimization approaches can help KEPs in defining which transplants should be made among all incompatible pairs according to some objective. The most common objective is to maximize the number of transplants. In this paper, we propose an integer programming model which addresses the objective of maximizing the expected number of transplants, given that there are equal probabilities of failure associated with vertices and arcs. The model is compact, i.e. has a polynomial number of decision variables and constraints, and therefore can be solved directly by a general purpose integer programming solver (e.g. Cplex).
NASA Astrophysics Data System (ADS)
Mendoza, J. H.; Díaz, C. F.; Acevedo, C. H.; Torres, Y.
2016-02-01
The orbital angular momentum of light has a big contribution in many engineering applications like optical communications, because this physical property allows eigenstates characteristic of the wavefront rotation when the beam is propagated. The nature of these eigenstates allows that information can be encoded and gives immunity to electromagnetic interference, allowing an increase of bandwidth, cadence and capacity of the communication channel. This work shown the methodology using nanometric thin films like Titanium based (TiO2) grown over strontium titanate (SrTiO3) support, to distinguish and discriminate a well- defined integer value of the topological charge of an OAM beam.
Multi-Temporal Decomposed Wind and Load Power Models for Electric Energy Systems
NASA Astrophysics Data System (ADS)
Abdel-Karim, Noha
electricity market rules capable of providing the right incentives to manage uncertainties and of differentiating various technologies according to the rate at which they can respond to ever changing conditions. Given the overall need for modeling uncertainties in electric energy systems, we consider in this thesis the problem of multi-temporal modeling of wind and demand power, in particular. Historic data is used to derive prediction models for several future time horizons. Short-term prediction models derived can be used for look-ahead economic dispatch and unit commitment, while the long-term annual predictive models can be used for investment planning. As expected, the accuracy of such predictive models depends on the time horizons over which the predictions are made, as well as on the nature of uncertain signals. It is shown that predictive models obtained using the same general modeling approaches result in different accuracy for wind than for demand power. In what follows, we introduce several models which have qualitatively different patterns, ranging from hourly to annual. We first transform historic time-stamped data into the Fourier Transform (Fr) representation. The frequency domain data representation is used to decompose the wind and load power signals and to derive predictive models relevant for short-term and long-term predictions using extracted spectral techniques. The short-term results are interpreted next as a Linear Prediction Coding Model (LPC) and its accuracy is analyzed. Next, a new Markov-Based Sensitivity Model (MBSM) for short term prediction has been proposed and the dispatched costs of uncertainties for different predictive models with comparisons have been developed. Moreover, the Discrete Markov Process (DMP) representation is applied to help assess probabilities of most likely short-, medium- and long-term states and the related multi-temporal risks. In addition, this thesis discusses operational impacts of wind power integration in
NASA Astrophysics Data System (ADS)
Ha, Jiho; Shin, Sungryul; Shin, Changsoo; Chung, Wookeen
2015-05-01
Because complex mixed waves are typically generated in elastic media, wavefield decomposition is required for such media to obtain migration images accurately. In isotropic media, this is achieved according to the Helmholtz decomposition theorem; in particular, the divergence operator is commonly applied to P-wavefield decomposition. In this study, two types of elastic reverse-time migration algorithms are proposed for decomposition of the P-wavefield without requiring the divergence operator. The first algorithm involves formulation of the stress tensor by spatially differentiated displacement according to the stress-strain relationship and is utilized to construct an imaging condition for the decomposed P-wavefield. We demonstrate this approach through numerical testing. The second algorithm allows us to obtain emphasized interfaces through the application of the absolute value function to decomposed wavefield in imaging condition. Because reverse-time migration can be defined by a zero-lag cross-correlation relationship between the partial-derivative wavefield and the observed wavefield data, we derive the virtual source to construct the partial-derivative wavefield based on a 2D staggered-grid finite-difference modeling method in the time domain. The explicitly computed partial-derivative wavefield from virtual sources with the stress tensor is in agreement with the partial-derivative wavefield directly computed from residual by between with and without a perturbation point in the subsurface. Moreover, the back-propagation technique is used to enhance the computational efficiency. To validate our two types of imaging conditions, numerical tests are conducted. The migration images created according to our imaging conditions can represent the subsurface structure accurately. Thus, we can confirm the feasibility of obtaining migration images of the decomposed P-wavefield without requiring the application of the divergence operator.
Pthreads vs MPI Parallel Performance of Angular-Domain Decomposed S
Azmy, Y.Y.; Barnett, D.A.
2000-05-07
Two programming models for parallelizing the Angular Domain Decomposition (ADD) of the discrete ordinates (S{sub n}) approximation of the neutron transport equation are examined. These are the shared memory model based on the POSIX threads (Pthreads) standard, and the message passing model based on the Message Passing Interface (MPI) standard. These standard libraries are available on most multiprocessor platforms thus making the resulting parallel codes widely portable. The question is: on a fixed platform, and for a particular code solving a given test problem, which of the two programming models delivers better parallel performance? Such comparison is possible on Symmetric Multi-Processors (SMP) architectures in which several CPUs physically share a common memory, and in addition are capable of emulating message passing functionality. Implementation of the two-dimensional,(S{sub n}), Arbitrarily High Order Transport (AHOT) code for solving neutron transport problems using these two parallelization models is described. Measured parallel performance of each model on the COMPAQ AlphaServer 8400 and the SGI Origin 2000 platforms is described, and comparison of the observed speedup for the two programming models is reported. For the case presented in this paper it appears that the MPI implementation scales better than the Pthreads implementation on both platforms.
NASA Astrophysics Data System (ADS)
Kim, Youngwoo; Woo, Kyoohee; Kim, Inhyuk; Cho, Yong Soo; Jeong, Sunho; Moon, Jooho
2013-10-01
Among various candidate materials, Cu2ZnSnS4 (CZTS) is a promising earth-abundant semiconductor for low-cost thin film solar cells. We report a facile, less toxic, highly concentrated synthetic method utilizing the heretofore unrecognized, easily decomposable capping ligand of triphenylphosphate, where phase-pure, single-crystalline, and well-dispersed colloidal CZTS nanocrystals were obtained. The favorable influence of the easily decomposable capping ligand on the microstructural evolution of device-quality CZTS absorber layers was clarified based on a comparative study with commonly used oleylamine-capped CZTS nanoparticles. The resulting CZTS nanoparticles enabled us to produce a dense and crack-free absorbing layer through annealing under a N2 + H2S (4%) atmosphere, demonstrating a solar cell with an efficiency of 3.6% under AM 1.5 illumination.Among various candidate materials, Cu2ZnSnS4 (CZTS) is a promising earth-abundant semiconductor for low-cost thin film solar cells. We report a facile, less toxic, highly concentrated synthetic method utilizing the heretofore unrecognized, easily decomposable capping ligand of triphenylphosphate, where phase-pure, single-crystalline, and well-dispersed colloidal CZTS nanocrystals were obtained. The favorable influence of the easily decomposable capping ligand on the microstructural evolution of device-quality CZTS absorber layers was clarified based on a comparative study with commonly used oleylamine-capped CZTS nanoparticles. The resulting CZTS nanoparticles enabled us to produce a dense and crack-free absorbing layer through annealing under a N2 + H2S (4%) atmosphere, demonstrating a solar cell with an efficiency of 3.6% under AM 1.5 illumination. Electronic supplementary information (ESI) available: Experimental methods for CZTS nanocrystal synthesis, device fabrication, and characterization; the size distribution and energy dispersive X-ray (EDX) spectra of the synthesized CZTS nanoparticles; UV-vis spectra of the
Lashermes, Gwenaëlle; Gainvors-Claisse, Angélique; Recous, Sylvie; Bertrand, Isabelle
2016-01-01
Soil microorganisms can control the soil cycles of carbon (C), and depending on their C-use efficiency (CUE), these microorganisms either contribute to C stabilization in soil or produce CO2 when decomposing organic matter. However, little is known regarding the enzyme investment of microbial decomposers and the effects on their CUE. Our objective was to elucidate the strategies of litter-decomposing fungi as a function of litter quality. Fungal biosynthesis and respiration were accounted for by quantifying the investment in enzyme synthesis and enzyme efficiency. The basidiomycete Phanerochaete chrysosporium was grown on the leaves, stems, and roots of maize over 126 days in controlled conditions. We periodically measured the fungal biomass, enzyme activity, and chemical composition of the remaining litter and continuously measured the evolved C–CO2. The CUE observed for the maize litter was highest in the leaves (0.63), intermediate in the roots (0.40), and lowest in the stems (0.38). However, the enzyme efficiency and investment in enzyme synthesis did not follow the same pattern. The amount of litter C decomposed per mole of C-acquiring hydrolase activity was 354 μg C in the leaves, 246 μg C in the roots, and 1541 μg C in the stems (enzyme efficiency: stems > leaves > roots). The fungus exhibited the highest investment in C-acquiring enzyme when grown on the roots and produced 40–80% less enzyme activity when grown on the stems and leaves (investment in enzymes: roots > leaves > stems). The CUE was dependent on the initial availability and replenishment of the soluble substrate fraction with the degradation products. The production of these compounds was either limited because of the low enzyme efficiency, which occurred in the roots, or because of the low investments in enzyme synthesis, which occurred in the stems. Fungal biosynthesis relied on the ability of the fungus to invest in enzyme synthesis and the efficient interactions between the enzymes
Lashermes, Gwenaëlle; Gainvors-Claisse, Angélique; Recous, Sylvie; Bertrand, Isabelle
2016-01-01
Soil microorganisms can control the soil cycles of carbon (C), and depending on their C-use efficiency (CUE), these microorganisms either contribute to C stabilization in soil or produce CO2 when decomposing organic matter. However, little is known regarding the enzyme investment of microbial decomposers and the effects on their CUE. Our objective was to elucidate the strategies of litter-decomposing fungi as a function of litter quality. Fungal biosynthesis and respiration were accounted for by quantifying the investment in enzyme synthesis and enzyme efficiency. The basidiomycete Phanerochaete chrysosporium was grown on the leaves, stems, and roots of maize over 126 days in controlled conditions. We periodically measured the fungal biomass, enzyme activity, and chemical composition of the remaining litter and continuously measured the evolved C–CO2. The CUE observed for the maize litter was highest in the leaves (0.63), intermediate in the roots (0.40), and lowest in the stems (0.38). However, the enzyme efficiency and investment in enzyme synthesis did not follow the same pattern. The amount of litter C decomposed per mole of C-acquiring hydrolase activity was 354 μg C in the leaves, 246 μg C in the roots, and 1541 μg C in the stems (enzyme efficiency: stems > leaves > roots). The fungus exhibited the highest investment in C-acquiring enzyme when grown on the roots and produced 40–80% less enzyme activity when grown on the stems and leaves (investment in enzymes: roots > leaves > stems). The CUE was dependent on the initial availability and replenishment of the soluble substrate fraction with the degradation products. The production of these compounds was either limited because of the low enzyme efficiency, which occurred in the roots, or because of the low investments in enzyme synthesis, which occurred in the stems. Fungal biosynthesis relied on the ability of the fungus to invest in enzyme synthesis and the efficient interactions between the enzymes
Lashermes, Gwenaëlle; Gainvors-Claisse, Angélique; Recous, Sylvie; Bertrand, Isabelle
2016-01-01
Soil microorganisms can control the soil cycles of carbon (C), and depending on their C-use efficiency (CUE), these microorganisms either contribute to C stabilization in soil or produce CO2 when decomposing organic matter. However, little is known regarding the enzyme investment of microbial decomposers and the effects on their CUE. Our objective was to elucidate the strategies of litter-decomposing fungi as a function of litter quality. Fungal biosynthesis and respiration were accounted for by quantifying the investment in enzyme synthesis and enzyme efficiency. The basidiomycete Phanerochaete chrysosporium was grown on the leaves, stems, and roots of maize over 126 days in controlled conditions. We periodically measured the fungal biomass, enzyme activity, and chemical composition of the remaining litter and continuously measured the evolved C-CO2. The CUE observed for the maize litter was highest in the leaves (0.63), intermediate in the roots (0.40), and lowest in the stems (0.38). However, the enzyme efficiency and investment in enzyme synthesis did not follow the same pattern. The amount of litter C decomposed per mole of C-acquiring hydrolase activity was 354 μg C in the leaves, 246 μg C in the roots, and 1541 μg C in the stems (enzyme efficiency: stems > leaves > roots). The fungus exhibited the highest investment in C-acquiring enzyme when grown on the roots and produced 40-80% less enzyme activity when grown on the stems and leaves (investment in enzymes: roots > leaves > stems). The CUE was dependent on the initial availability and replenishment of the soluble substrate fraction with the degradation products. The production of these compounds was either limited because of the low enzyme efficiency, which occurred in the roots, or because of the low investments in enzyme synthesis, which occurred in the stems. Fungal biosynthesis relied on the ability of the fungus to invest in enzyme synthesis and the efficient interactions between the enzymes and
Lashermes, Gwenaëlle; Gainvors-Claisse, Angélique; Recous, Sylvie; Bertrand, Isabelle
2016-01-01
Soil microorganisms can control the soil cycles of carbon (C), and depending on their C-use efficiency (CUE), these microorganisms either contribute to C stabilization in soil or produce CO2 when decomposing organic matter. However, little is known regarding the enzyme investment of microbial decomposers and the effects on their CUE. Our objective was to elucidate the strategies of litter-decomposing fungi as a function of litter quality. Fungal biosynthesis and respiration were accounted for by quantifying the investment in enzyme synthesis and enzyme efficiency. The basidiomycete Phanerochaete chrysosporium was grown on the leaves, stems, and roots of maize over 126 days in controlled conditions. We periodically measured the fungal biomass, enzyme activity, and chemical composition of the remaining litter and continuously measured the evolved C-CO2. The CUE observed for the maize litter was highest in the leaves (0.63), intermediate in the roots (0.40), and lowest in the stems (0.38). However, the enzyme efficiency and investment in enzyme synthesis did not follow the same pattern. The amount of litter C decomposed per mole of C-acquiring hydrolase activity was 354 μg C in the leaves, 246 μg C in the roots, and 1541 μg C in the stems (enzyme efficiency: stems > leaves > roots). The fungus exhibited the highest investment in C-acquiring enzyme when grown on the roots and produced 40-80% less enzyme activity when grown on the stems and leaves (investment in enzymes: roots > leaves > stems). The CUE was dependent on the initial availability and replenishment of the soluble substrate fraction with the degradation products. The production of these compounds was either limited because of the low enzyme efficiency, which occurred in the roots, or because of the low investments in enzyme synthesis, which occurred in the stems. Fungal biosynthesis relied on the ability of the fungus to invest in enzyme synthesis and the efficient interactions between the enzymes and
NASA Technical Reports Server (NTRS)
Elrad, Tzilla (Editor); Filman, Robert E. (Editor); Bader, Atef (Editor)
2001-01-01
Computer science has experienced an evolution in programming languages and systems from the crude assembly and machine codes of the earliest computers through concepts such as formula translation, procedural programming, structured programming, functional programming, logic programming, and programming with abstract data types. Each of these steps in programming technology has advanced our ability to achieve clear separation of concerns at the source code level. Currently, the dominant programming paradigm is object-oriented programming - the idea that one builds a software system by decomposing a problem into objects and then writing the code of those objects. Such objects abstract together behavior and data into a single conceptual and physical entity. Object-orientation is reflected in the entire spectrum of current software development methodologies and tools - we have OO methodologies, analysis and design tools, and OO programming languages. Writing complex applications such as graphical user interfaces, operating systems, and distributed applications while maintaining comprehensible source code has been made possible with OOP. Success at developing simpler systems leads to aspirations for greater complexity. Object orientation is a clever idea, but has certain limitations. We are now seeing that many requirements do not decompose neatly into behavior centered on a single locus. Object technology has difficulty localizing concerns invoking global constraints and pandemic behaviors, appropriately segregating concerns, and applying domain-specific knowledge. Post-object programming (POP) mechanisms that look to increase the expressiveness of the OO paradigm are a fertile arena for current research. Examples of POP technologies include domain-specific languages, generative programming, generic programming, constraint languages, reflection and metaprogramming, feature-oriented development, views/viewpoints, and asynchronous message brokering. (Czarneclu and
Schmidt, Anja; John, Katharina; Arida, Gertrudo; Auge, Harald; Brandl, Roland; Horgan, Finbarr G; Hotes, Stefan; Marquez, Leonardo; Radermacher, Nico; Settele, Josef; Wolters, Volkmar; Schädler, Martin
2015-01-01
Decomposers provide an essential ecosystem service that contributes to sustainable production in rice ecosystems by driving the release of nutrients from organic crop residues. During a single rice crop cycle we examined the effects of four different crop residue management practices (rice straw or ash of burned straw scattered on the soil surface or incorporated into the soil) on rice straw decomposition and on the abundance of aquatic and soil-dwelling invertebrates. Mass loss of rice straw in litterbags of two different mesh sizes that either prevented or allowed access of meso- and macro-invertebrates was used as a proxy for decomposition rates. Invertebrates significantly increased total loss of litter mass by up to 30%. Initially, the contribution of invertebrates to decomposition was significantly smaller in plots with rice straw scattered on the soil surface; however, this effect disappeared later in the season. We found no significant responses in microbial decomposition rates to management practices. The abundance of aquatic fauna was higher in fields with rice straw amendment, whereas the abundance of soil fauna fluctuated considerably. There was a clear separation between the overall invertebrate community structure in response to the ash and straw treatments. However, we found no correlation between litter mass loss and abundances of various lineages of invertebrates. Our results indicate that invertebrates can contribute to soil fertility in irrigated paddy fields by decomposing rice straw, and that their abundance as well as efficiency in decomposition may be promoted by crop residue management practices. PMID:26225556
NASA Astrophysics Data System (ADS)
Fujii, Fumio; Yamakawa, Yuki; Noguchi, Hirohisa
2010-07-01
In the previous publications of the authors, an eigenanalysis-free computational procedure has been proposed to extract the bifurcation buckling mode(s) from the LDL T -decomposed symmetric stiffness matrix in the vicinity of a stability point. Any eigensolver, for instance, inverse iteration or subspace method, is not necessary. The procedure has been verified in numerical examples and well works in multiple and clustered bifurcation problems too. This present paper will extend the eigenanalysis-free procedure to the LDU-decomposed non-symmetric Jacobian matrix, from which both left and right critical eigenvectors relevant to the stability point may be extracted in a similar way. The idea is mathematical and totally independent of the physical problem to be solved, so that it is applicable to any non-symmetric square matrix in stability problems including plasticity with non-associated flow rules, contact and fluid-structure interaction. The linear-algebraic background of non-symmetric eigenvalue problems is firstly described. The present paper will then mention the role play of the left and right critical eigenvectors in stability analysis and the eigenanalysis-free LDU-procedure is proposed. Numerical examples of elastoplastic bifurcation are illustrated for verification and discussion. In APPENDICES, a bench model visualizes the mechanical meaning of the left and right critical singular vectors of a rectangular matrix.
Zhang, Xiaoxing; Chen, Qinchuan; Tang, Ju; Hu, Weihua; Zhang, Jinbin
2014-01-01
The detection of partial discharge by analyzing the components of SF6 gas in gas-insulated switchgears is important to the diagnosis and assessment of the operational state of power equipment. A gas sensor based on anatase TiO2 is used to detect decomposed gases in SF6. In this paper, first-principle density functional theory calculations are adopted to analyze the adsorption of SO2, SOF2, and SO2F2, the primary decomposition by-products of SF6 under partial discharge, on anatase (101) and (001) surfaces. Simulation results show that the perfect anatase (001) surface has a stronger interaction with the three gases than that of anatase (101), and both surfaces are more sensitive and selective to SO2 than to SOF2 and SO2F2. The selection of a defect surface to SO2, SOF2, and SO2F2 differs from that of a perfect surface. This theoretical result is corroborated by the sensing experiment using a TiO2 nanotube array (TNTA) gas sensor. The calculated values are analyzed to explain the results of the Pt-doped TNTA gas sensor sensing experiment. The results imply that the deposited Pt nanoparticles on the surface increase the active sites of the surface and the gas molecules may decompose upon adsorption on the active sites. PMID:24755845
Kim, Min-Seok; Lee, Woo-Jin; Cho, Ki-Hyun; Ahn, Jae-Pyoung; Sung, Yun-Mo
2016-07-26
Dramatic enhancements in the figure of merit have been obtained in bulk thermoelectric materials by doping, band engineering, and nanostructuring. Especially, in p-type thermoelectrics, high figure of merits near 2.0 have been reported in a few papers through the reduction in lattice thermal conductivity and the advancement in power factors. However, there exists no report on the n-type systems showing high figure of merits because of their intrinsically low Seebeck coefficients. Here, we demonstrate that a nanostructured bulk n-type thermoelectric material that was assembled by sintering spinodally decomposed lead chalcogenide nanoparticles having a composition of PbSe0.5Te0.5 reaches a high figure of merit of 1.85. The spinodally decomposed nanoparticles permit our thermoelectric material to have extremely low lattice thermal conductivity and a high power factor as a result of nanostructuring, electronic optimization, insertion of an impurity phase and phase change in local areas. We propose that this interesting concept would be one of the promising approaches that overcome limitation arising from the fact that most parameters in the figure of merit are closely correlated. PMID:27397515
Schmidt, Anja; John, Katharina; Arida, Gertrudo; Auge, Harald; Brandl, Roland; Horgan, Finbarr G.; Hotes, Stefan; Marquez, Leonardo; Radermacher, Nico; Settele, Josef; Wolters, Volkmar; Schädler, Martin
2015-01-01
Decomposers provide an essential ecosystem service that contributes to sustainable production in rice ecosystems by driving the release of nutrients from organic crop residues. During a single rice crop cycle we examined the effects of four different crop residue management practices (rice straw or ash of burned straw scattered on the soil surface or incorporated into the soil) on rice straw decomposition and on the abundance of aquatic and soil-dwelling invertebrates. Mass loss of rice straw in litterbags of two different mesh sizes that either prevented or allowed access of meso- and macro-invertebrates was used as a proxy for decomposition rates. Invertebrates significantly increased total loss of litter mass by up to 30%. Initially, the contribution of invertebrates to decomposition was significantly smaller in plots with rice straw scattered on the soil surface; however, this effect disappeared later in the season. We found no significant responses in microbial decomposition rates to management practices. The abundance of aquatic fauna was higher in fields with rice straw amendment, whereas the abundance of soil fauna fluctuated considerably. There was a clear separation between the overall invertebrate community structure in response to the ash and straw treatments. However, we found no correlation between litter mass loss and abundances of various lineages of invertebrates. Our results indicate that invertebrates can contribute to soil fertility in irrigated paddy fields by decomposing rice straw, and that their abundance as well as efficiency in decomposition may be promoted by crop residue management practices. PMID:26225556
Kaiser, Christina; Franklin, Oskar; Richter, Andreas; Dieckmann, Ulf
2015-01-01
The chemical structure of organic matter has been shown to be only marginally important for its decomposability by microorganisms. The question of why organic matter does accumulate in the face of powerful microbial degraders is thus key for understanding terrestrial carbon and nitrogen cycling. Here we demonstrate, based on an individual-based microbial community model, that social dynamics among microbes producing extracellular enzymes (‘decomposers') and microbes exploiting the catalytic activities of others (‘cheaters') regulate organic matter turnover. We show that the presence of cheaters increases nitrogen retention and organic matter build-up by downregulating the ratio of extracellular enzymes to total microbial biomass, allowing nitrogen-rich microbial necromass to accumulate. Moreover, increasing catalytic efficiencies of enzymes are outbalanced by a strong negative feedback on enzyme producers, leading to less enzymes being produced at the community level. Our results thus reveal a possible control mechanism that may buffer soil CO2 emissions in a future climate. PMID:26621582
NASA Astrophysics Data System (ADS)
Zhang, Xiaoxing; Chen, Qinchuan; Tang, Ju; Hu, Weihua; Zhang, Jinbin
2014-04-01
The detection of partial discharge by analyzing the components of SF6 gas in gas-insulated switchgears is important to the diagnosis and assessment of the operational state of power equipment. A gas sensor based on anatase TiO2 is used to detect decomposed gases in SF6. In this paper, first-principle density functional theory calculations are adopted to analyze the adsorption of SO2, SOF2, and SO2F2, the primary decomposition by-products of SF6 under partial discharge, on anatase (101) and (001) surfaces. Simulation results show that the perfect anatase (001) surface has a stronger interaction with the three gases than that of anatase (101), and both surfaces are more sensitive and selective to SO2 than to SOF2 and SO2F2. The selection of a defect surface to SO2, SOF2, and SO2F2 differs from that of a perfect surface. This theoretical result is corroborated by the sensing experiment using a TiO2 nanotube array (TNTA) gas sensor. The calculated values are analyzed to explain the results of the Pt-doped TNTA gas sensor sensing experiment. The results imply that the deposited Pt nanoparticles on the surface increase the active sites of the surface and the gas molecules may decompose upon adsorption on the active sites.
CROSSER - CUMULATIVE BINOMIAL PROGRAMS
NASA Technical Reports Server (NTRS)
Bowerman, P. N.
1994-01-01
The cumulative binomial program, CROSSER, is one of a set of three programs which calculate cumulative binomial probability distributions for arbitrary inputs. The three programs, CROSSER, CUMBIN (NPO-17555), and NEWTONP (NPO-17556), can be used independently of one another. CROSSER can be used by statisticians and users of statistical procedures, test planners, designers, and numerical analysts. The program has been used for reliability/availability calculations. CROSSER calculates the point at which the reliability of a k-out-of-n system equals the common reliability of the n components. It is designed to work well with all integer values 0 < k <= n. To run the program, the user simply runs the executable version and inputs the information requested by the program. The program is not designed to weed out incorrect inputs, so the user must take care to make sure the inputs are correct. Once all input has been entered, the program calculates and lists the result. It also lists the number of iterations of Newton's method required to calculate the answer within the given error. The CROSSER program is written in C. It was developed on an IBM AT with a numeric co-processor using Microsoft C 5.0. Because the source code is written using standard C structures and functions, it should compile correctly with most C compilers. The program format is interactive. It has been implemented under DOS 3.2 and has a memory requirement of 26K. CROSSER was developed in 1988.
NASA Astrophysics Data System (ADS)
Kiryakova, Virginia S.
2012-11-01
The Laplace Transform (LT) serves as a basis of the Operational Calculus (OC), widely explored by engineers and applied scientists in solving mathematical models for their practical needs. This transform is closely related to the exponential and trigonometric functions (exp, cos, sin) and to the classical differentiation and integration operators, reducing them to simple algebraic operations. Thus, the classical LT and the OC give useful tool to handle differential equations and systems with constant coefficients. Several generalizations of the LT have been introduced to allow solving, in a similar way, of differential equations with variable coefficients and of higher integer orders, as well as of fractional (arbitrary non-integer) orders. Note that fractional order mathematical models are recently widely used to describe better various systems and phenomena of the real world. This paper surveys briefly some of our results on classes of such integral transforms, that can be obtained from the LT by means of "transmutations" which are operators of the generalized fractional calculus (GFC). On the list of these Laplace-type integral transforms, we consider the Borel-Dzrbashjan, Meijer, Krätzel, Obrechkoff, generalized Obrechkoff (multi-index Borel-Dzrbashjan) transforms, etc. All of them are G- and H-integral transforms of convolutional type, having as kernels Meijer's G- or Fox's H-functions. Besides, some special functions (also being G- and H-functions), among them - the generalized Bessel-type and Mittag-Leffler (M-L) type functions, are generating Gel'fond-Leontiev (G-L) operators of generalized differentiation and integration, which happen to be also operators of GFC. Our integral transforms have operational properties analogous to those of the LT - they do algebrize the G-L generalized integrations and differentiations, and thus can serve for solving wide classes of differential equations with variable coefficients of arbitrary, including non-integer order
NASA Astrophysics Data System (ADS)
Baker, N. R.; Allison, S. D.
2015-12-01
The return of organic carbon to the atmosphere through terrestrial decomposition is mediated through the breakdown of complex organic polymers by extracellular enzymes produced by microbial decomposer communities. It is unclear how microbial diversity constrains enzymatic potential, making it difficult to predict future carbon cycling under climate change scenarios that could alter microbial community composition. To address this question, we deployed fine-pore nylon mesh "microbial cage" litterbags containing grassland litter with and without local inoculum across five sites in southern California, spanning a gradient of 4.0-24.5º C in mean annual temperature and 129-630 mm mean annual precipitation. Litterbags were deployed in October 2014 and collected in March and June 2015. Collected litterbags were assayed for mass loss and potential activity of nine extracellular enzyme classes. We hypothesized that extracellular enzyme potential would be greatest in litter transplanted to moister sites, given the importance of moisture as a driver of ecosystem function in southern California. We also hypothesized that litter inoculated with local microbiota would exhibit greater extracellular enzyme potential than litter containing only grassland microbes, with the assumption that local decomposer microbes would be more effective than grassland microbes at decomposing litter in their native environment. We found that potential extracellular enzyme activities varied significantly (p<0.01) by site for all nine enzyme classes. Six of the nine enzymes assayed (and six of the seven hydrolytic enzymes) failed to support our hypothesis, exhibiting significantly lower enzyme activity in the coldest and wettest site in comparison to the other four sites (p<0.01). Conversely, both oxidative enzymes assayed exhibited the greatest observed activity in the coldest, wettest site, supporting our hypothesis and indicating that hydrolytic and oxidative enzyme classes from the same
NASA Astrophysics Data System (ADS)
Scammell, H. D.; Sushkov, O. P.
2015-02-01
We consider the Bose condensation of bosonic particles with spin 1 /2 . The condensation is driven by an external magnetic field. Our work is motivated by ideas of quantum critical deconfinement and bosonic spinons in spin liquid states. We show that both the nature of the novel Bose condensate and the excitation spectrum are fundamentally different from that in the usual integer spin case. We predict two massive ("Higgs") excitations and two massless Goldstone excitations. One of the Goldstone excitations has a linear excitation spectrum and another has a quadratic spectrum. This implies that the Bose condensate does not support superfluidity, the Landau criterion is essentially violated. We formulate a "smoking gun" criterion for searches of the novel Bose condensation.
Kim, Suhyun Jung, Younheum; Kim, Joong Jung; Lee, Sunyoung; Lee, Haebum; Kondo, Yukihito
2014-10-15
Scanning moiré fringe (SMF) imaging by high-angle annular dark field scanning transmission electron microscopy was used to measure the strain field in the channel of a transistor with a CoSi{sub 2} source and drain. Nanometer-scale SMFs were formed with a scanning grating size of d{sub s} at integer multiples of the Si crystal lattice spacing d{sub l} (d{sub s} ∼ nd{sub l}, n = 2, 3, 4, 5). The moiré fringe formula was modified to establish a method for quantifying strain measurement. We showed that strain fields in a transistor measured by SMF images were reproducible with an accuracy of 0.02%.