Software For Integer Programming
NASA Technical Reports Server (NTRS)
Fogle, F. R.
1992-01-01
Improved Exploratory Search Technique for Pure Integer Linear Programming Problems (IESIP) program optimizes objective function of variables subject to confining functions or constraints, using discrete optimization or integer programming. Enables rapid solution of problems up to 10 variables in size. Integer programming required for accuracy in modeling systems containing small number of components, distribution of goods, scheduling operations on machine tools, and scheduling production in general. Written in Borland's TURBO Pascal.
Integer programming, fullerenes and nanotubes
Fowler, P.W.; Hansen, P.; Leroy, C.; Sachs, H.
1994-12-31
Graph theoretic and integer programming techniques provide answers to a series of questions in organic chemistry. We focus on problems on fullerenes, or closed carbon-cage molecules with large number of carbon atoms, and nanotubes, which are similar open or closed end tubes of carbon atoms with a few manometer diameter. These problems include isomer enumeration, counting Kekul{acute e} structures (or perfect matchings), finding Kekul{acute e} structures with a maximum number of resonant hexagons (i.e., determining the Clar and Fries numbers) and finding the stability number of fullerenes.
Ensemble segmentation using efficient integer linear programming.
Alush, Amir; Goldberger, Jacob
2012-10-01
We present a method for combining several segmentations of an image into a single one that in some sense is the average segmentation in order to achieve a more reliable and accurate segmentation result. The goal is to find a point in the "space of segmentations" which is close to all the individual segmentations. We present an algorithm for segmentation averaging. The image is first oversegmented into superpixels. Next, each segmentation is projected onto the superpixel map. An instance of the EM algorithm combined with integer linear programming is applied on the set of binary merging decisions of neighboring superpixels to obtain the average segmentation. Apart from segmentation averaging, the algorithm also reports the reliability of each segmentation. The performance of the proposed algorithm is demonstrated on manually annotated images from the Berkeley segmentation data set and on the results of automatic segmentation algorithms.
New Approaches for Very Large-Scale Integer Programming
2016-06-24
heuristics for integer programs in order to rapidly improve dual bounds. 2. Choosing good branching variables in branch-and-bound algorithms for MIP. 3...Machine Learning in solving MIPs. 4. Parallel Processing in Solving MIPS. The new algorithms are computational tested and, in many cases, outperform...existing algorithms . This research has been presented at several conferences and has and will appear in archival journals. 15. SUBJECT TERMS integer
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…
An Integer Programming Approach to School District Financial Management.
ERIC Educational Resources Information Center
Dembowski, Frederick L.
Because of the nature of school district cash flows, there are opportunities for investing surplus cash and the necessity to borrow cash in deficit periods. The term structure of interest rates makes the manual determination of the optimal financial package impossible. In this research, an integer programming model of this cash management process…
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…
Solving linear integer programming problems by a novel neural model.
Cavalieri, S
1999-02-01
The paper deals with integer linear programming problems. As is well known, these are extremely complex problems, even when the number of integer variables is quite low. Literature provides examples of various methods to solve such problems, some of which are of a heuristic nature. This paper proposes an alternative strategy based on the Hopfield neural network. The advantage of the strategy essentially lies in the fact that hardware implementation of the neural model allows for the time required to obtain a solution so as not depend on the size of the problem to be solved. The paper presents a particular class of integer linear programming problems, including well-known problems such as the Travelling Salesman Problem and the Set Covering Problem. After a brief description of this class of problems, it is demonstrated that the original Hopfield model is incapable of supplying valid solutions. This is attributed to the presence of constant bias currents in the dynamic of the neural model. A demonstration of this is given and then a novel neural model is presented which continues to be based on the same architecture as the Hopfield model, but introduces modifications thanks to which the integer linear programming problems presented can be solved. Some numerical examples and concluding remarks highlight the solving capacity of the novel neural model.
Extracting vascular networks under physiological constraints via integer programming.
Rempfler, Markus; Schneider, Matthias; Ielacqua, Giovanna D; Xiao, Xianghui; Stock, Stuart R; Klohs, Jan; Székely, Gábor; Andres, Bjoern; Menze, Bjoern H
2014-01-01
We introduce an integer programming-based approach to vessel network extraction that enforces global physiological constraints on the vessel structure and learn this prior from a high-resolution reference network. The method accounts for both image evidence and geometric relationships between vessels by formulating and solving an integer programming problem. Starting from an over-connected network, it is pruning vessel stumps and spurious connections by evaluating bifurcation angle and connectivity of the graph. We utilize a high-resolution micro computed tomography (μCT) dataset of a cerebrovascular corrosion cast to obtain a reference network, 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.
Stochastic Dynamic Mixed-Integer Programming (SD-MIP)
2015-05-05
door to stochastic optimization models, which are typically dynamic in nature. This project lays the foundation for stochastic dynamic mixed...project lays the foundation for stochastic dynamic mixed-integer and linear programming (SD-MIP). This project has produced several new ideas in...models. Recent research has opened the door to stochastic optimization models, which are typically dynamic in nature. This project lays the foundation for
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.
Integer programming model for optimizing bus timetable using genetic algorithm
NASA Astrophysics Data System (ADS)
Wihartiko, F. D.; Buono, A.; Silalahi, B. P.
2017-01-01
Bus timetable gave an information for passengers to ensure the availability of bus services. Timetable optimal condition happened when bus trips frequency could adapt and suit with passenger demand. In the peak time, the number of bus trips would be larger than the off-peak time. If the number of bus trips were more frequent than the optimal condition, it would make a high operating cost for bus operator. Conversely, if the number of trip was less than optimal condition, it would make a bad quality service for passengers. In this paper, the bus timetabling problem would be solved by integer programming model with modified genetic algorithm. Modification was placed in the chromosomes design, initial population recovery technique, chromosomes reconstruction and chromosomes extermination on specific generation. The result of this model gave the optimal solution with accuracy 99.1%.
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.
Reconstructing cerebrovascular networks under local physiological constraints by integer programming
Rempfler, Markus; Schneider, Matthias; Ielacqua, Giovanna D.; ...
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.
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.
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…
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.
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.
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.
Maximum likelihood pedigree reconstruction using integer linear programming.
Cussens, James; Bartlett, Mark; Jones, Elinor M; Sheehan, Nuala A
2013-01-01
Large population biobanks of unrelated individuals have been highly successful in detecting common genetic variants affecting diseases of public health concern. However, they lack the statistical power to detect more modest gene-gene and gene-environment interaction effects or the effects of rare variants for which related individuals are ideally required. In reality, most large population studies will undoubtedly contain sets of undeclared relatives, or pedigrees. Although a crude measure of relatedness might sometimes suffice, having a good estimate of the true pedigree would be much more informative if this could be obtained efficiently. Relatives are more likely to share longer haplotypes around disease susceptibility loci and are hence biologically more informative for rare variants than unrelated cases and controls. Distant relatives are arguably more useful for detecting variants with small effects because they are less likely to share masking environmental effects. Moreover, the identification of relatives enables appropriate adjustments of statistical analyses that typically assume unrelatedness. We propose to exploit an integer linear programming optimisation approach to pedigree learning, which is adapted to find valid pedigrees by imposing appropriate constraints. Our method is not restricted to small pedigrees and is guaranteed to return a maximum likelihood pedigree. With additional constraints, we can also search for multiple high-probability pedigrees and thus account for the inherent uncertainty in any particular pedigree reconstruction. The true pedigree is found very quickly by comparison with other methods when all individuals are observed. Extensions to more complex problems seem feasible.
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.
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.
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.
Molecular solutions to the binary integer programming problem based on DNA computation.
Yeh, Chung-Wei; Chu, Chih-Ping; Wu, Kee-Rong
2006-01-01
Binary optimization is a widely investigated topic in integer linear programming. This study proposes a DNA-based computing algorithm for solving the significantly large binary integer programming (BIP) problem. The proposed approach is based upon Adleman and Lipton's DNA operations to solve the BIP problem. The potential of DNA computation for the BIP problem is promising given the operational time complexity of O(nxk).
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.
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.
Optimizing Marine Corps Personnel Assignments Using an Integer Programming Model
2012-12-01
making. The advancement of computers and related technology has played a huge role in the proliferation of linear programming. More often than not...2012 BAH Rates-with Dependents. Defense Travel Mangement Office. (2011, December). 2012 BAH Rates-without Dependents. M ileage C ost 1 Per D iem
He, L; Huang, G H; Lu, H W
2009-04-01
A number of inexact programming methods have been developed for municipal solid waste management under uncertainty. However, most of them do not allow the parameters in the objective and constraints of a programming problem to be functional intervals (i.e., the lower and upper bounds of the intervals are functions of impact factors). In this study, a flexible interval mixed-integer bi-infinite programming (FIMIBIP) method is developed in response to the above concern. A case study is also conducted; the solutions are then compared with those obtained from interval mixed-integer bi-infinite programming (IMIBIP) and fuzzy interval mixed-integer programming (FIMIP) methods. It is indicated that the solutions through FIMIBIP can provide decision support for cost-effectively diverting municipal solid waste, and for sizing, timing and siting the facilities' expansion during the entire planning horizon. These schemes are more flexible than those identified through IMIBIP since the tolerance intervals are introduced to measure the level of constraints satisfaction. The FIMIBIP schemes may also be robust since the solutions are "globally-optimal" under all scenarios caused by the fluctuation of gas/energy prices, while the conventional ones are merely "locally-optimal" under a certain scenario.
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.
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.
Optimized Waterspace Management and Scheduling Using Mixed-Integer Linear Programming
2016-01-01
TECHNICAL REPORT NSWC PCD TR 2015-003 OPTIMIZED WATERSPACE MANAGEMENT AND SCHEDULING USING MIXED-INTEGER LINEAR PROGRAMMING...effects on optimization quality . 24 3 NSWC PCD TR 2015-003 Optimized Waterspace Mgt 1 Introduction The use of autonomous systems to perform increasingly...constraints required for the mathematical formulation of the MCM scheduling problem pertaining to the survey constraints and logistics management . The
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.
Stacking-sequence optimization for buckling of laminated plates by integer programming
NASA Technical Reports Server (NTRS)
Haftka, Raphael T.; Walsh, Joanne L.
1991-01-01
Integer-programming formulations for the design of symmetric and balanced laminated plates under biaxial compression are presented. Both maximization of buckling load for given total thickness, and the minimization of total thickness subject to a buckling constraint are formulated. The design variables that define the stacking sequence of the laminate are zero-one integers. It is shown that the formulation results in a linear optimization problem that can be solved on readily aviable software. Constraints on the stacking sequence such as a limit on the number of contiguous plies of the same orientation and limits on in-plane stiffnesses are easily accommodated. Examples are presented for graphite-epoxy plates under uniaxial and biaxial compression using a commercial software package based on the branch-and-bound algorithm.
Stacking-sequence optimization for buckling of laminated plates by integer programming
NASA Technical Reports Server (NTRS)
Haftka, Raphael T.; Walsh, Joanne L.
1991-01-01
Integer-programming formulations for the design of symmetric and balanced laminated plates under biaxial compression are presented. Both maximization of buckling load for a given total thickness and the minimization of total thickness subject to a buckling constraint are formulated. The design variables that define the stacking sequence of the laminate are zero-one integers. It is shown that the formulation results in a linear optimization problem that can be solved on readily available software. This is in contrast to the continuous case, where the design variables are the thicknesses of layers with specified ply orientations, and the optimization problem is nonlinear. Constraints on the stacking sequence such as a limit on the number of contiguous plies of the same orientation and limits on in-plane stiffnesses are easily accommodated. Examples are presented for graphite-epoxy plates under uniaxial and biaxial compression using a commercial software package based on the branch-and-bound algorithm.
Models and Algorithms Involving Very Large Scale Stochastic Mixed-Integer Programs
2011-02-28
give rise to a non - convex and discontinuous recourse function that may be difficult to optimize . As a result of this project, there have been... convex , the master problem in (3.1.6)-(3.1.9) is a non - convex mixed-integer program, and as indicated in [C.1], this approach is not scalable without...the first stage would result in a Benders’ master program which is non - convex , leading to a problem that is not any easier than (3.1.5). Nevertheless
Integer programming-based approach to allocation of reporter genes for cell array analysis.
Hayashida, Morihiro; Sun, Fuyan; Aburatani, Sachiyo; Horimoto, Katsuhisa; Akutsu, Tatsuya
2008-01-01
In this paper, we consider the problem of selecting the most effective set of reporter genes for analysis of biological networks using cell microarrays. We propose two graph theoretic formulations of the reporter gene allocation problem, and show that both problems are hard to approximate. We propose integer programming-based methods for solving practical instances of these problems optimally. We apply them to apoptosis pathway maps, and discuss the biological significance of the result. We also apply them to artificial networks, the result of which shows that optimal solutions can be obtained within several seconds for networks with 10,000 nodes.
Obtaining lower bounds from the progressive hedging algorithm for stochastic mixed-integer programs
Gade, Dinakar; Hackebeil, Gabriel; Ryan, Sarah M.; ...
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; ...
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.
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.
Edit distance for marked point processes revisited: An implementation by binary integer programming
NASA Astrophysics Data System (ADS)
Hirata, Yoshito; Aihara, Kazuyuki
2015-12-01
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.
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.
On control of singleton attractors in multiple Boolean networks: integer programming-based method
2014-01-01
Background Boolean network (BN) is a mathematical model for genetic network and control of genetic networks has become an important issue owing to their potential application in the field of drug discovery and treatment of intractable diseases. Early researches have focused primarily on the analysis of attractor control for a randomly generated BN. However, one may also consider how anti-cancer drugs act in both normal and cancer cells. Thus, the development of controls for multiple BNs is an important and interesting challenge. Results In this article, we formulate three novel problems about attractor control for two BNs (i.e., normal cell and cancer cell). The first is about finding a control that can significantly damage cancer cells but has a limited damage to normal cells. The second is about finding a control for normal cells with a guaranteed damaging effect on cancer cells. Finally, we formulate a definition for finding a control for cancer cells with limited damaging effect on normal cells. We propose integer programming-based methods for solving these problems in a unified manner, and we conduct computational experiments to illustrate the efficiency and the effectiveness of our method for our multiple-BN control problems. Conclusions We present three novel control problems for multiple BNs that are realistic control models for gene regulation networks and adopt an integer programming approach to address these problems. Experimental results indicate that our proposed method is useful and effective for moderate size BNs. PMID:24565276
NASA Astrophysics Data System (ADS)
Sakakibara, Kazutoshi; Tian, Yajie; Nishikawa, Ikuko
We discuss the planning of transportation by trucks over a multi-day period. Each truck collects loads from suppliers and delivers them to assembly plants or a truck terminal. By exploiting the truck terminal as a temporal storage, we aim to increase the load ratio of each truck and to minimize the lead time for transportation. In this paper, we show a mixed integer programming model which represents each product explicitly, and discuss the decomposition of the problem into a problem of delivery and storage, and a problem of vehicle routing. Based on this model, we propose a relax-and-fix type heuristic in which decision variables are fixed one by one by mathematical programming techniques such as branch-and-bound methods.
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.
Estimating Tree-Structured Covariance Matrices via Mixed-Integer Programming.
Bravo, Héctor Corrada; Wright, Stephen; Eng, Kevin H; Keles, Sündüz; Wahba, Grace
2009-01-01
We present a novel method for estimating tree-structured covariance matrices directly from observed continuous data. Specifically, we estimate a covariance matrix from observations of p continuous random variables encoding a stochastic process over a tree with p leaves. A representation of these classes of matrices as linear combinations of rank-one matrices indicating object partitions is used to formulate estimation as instances of well-studied numerical optimization problems.In particular, our estimates are based on projection, where the covariance estimate is the nearest tree-structured covariance matrix to an observed sample covariance matrix. The problem is posed as a linear or quadratic mixed-integer program (MIP) where a setting of the integer variables in the MIP specifies a set of tree topologies of the structured covariance matrix. We solve these problems to optimality using efficient and robust existing MIP solvers.We present a case study in phylogenetic analysis of gene expression and a simulation study comparing our method to distance-based tree estimating procedures.
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…
Wu, Z; Zhang, Y
2008-01-01
The double digestion problem for DNA restriction mapping has been proved to be NP-complete and intractable if the numbers of the DNA fragments become large. Several approaches to the problem have been tested and proved to be effective only for small problems. In this paper, we formulate the problem as a mixed-integer linear program (MIP) by following (Waterman, 1995) in a slightly different form. With this formulation and using state-of-the-art integer programming techniques, we can solve randomly generated problems whose search space sizes are many-magnitude larger than previously reported testing sizes.
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.
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.
NASA Astrophysics Data System (ADS)
Onoyama, Takashi; Kubota, Sen; Maekawa, Takuya; Komoda, Norihisa
Adequate response performance is required for the planning of a cooperative logistic network covering multiple enterprises, because this process needs a human expert's evaluation from many aspects. To satisfy this requirement, we propose an accurate model based on mixed integer programming for optimizing cooperative logistics networks where “round transportation” exists together with “depot transportation” including lower limit constraints of loading ratio for round transportation vehicles. Furthermore, to achieve interactive response performance, a dummy load is introduced into the model instead of integer variables. The experimental result shows the proposed method obtains an accurate solution within interactive response time.
Uncovering signal transduction networks from high-throughput data by integer linear programming.
Zhao, Xing-Ming; Wang, Rui-Sheng; Chen, Luonan; Aihara, Kazuyuki
2008-05-01
Signal transduction is an important process that transmits signals from the outside of a cell to the inside to mediate sophisticated biological responses. Effective computational models to unravel such a process by taking advantage of high-throughput genomic and proteomic data are needed to understand the essential mechanisms underlying the signaling pathways. In this article, we propose a novel method for uncovering signal transduction networks (STNs) by integrating protein interaction with gene expression data. Specifically, we formulate STN identification problem as an integer linear programming (ILP) model, which can be actually solved by a relaxed linear programming algorithm and is flexible for handling various prior information without any restriction on the network structures. The numerical results on yeast MAPK signaling pathways demonstrate that the proposed ILP model is able to uncover STNs or pathways in an efficient and accurate manner. In particular, the prediction results are found to be in high agreement with current biological knowledge and available information in literature. In addition, the proposed model is simple to be interpreted and easy to be implemented even for a large-scale system.
Profiler - A Fast and Versatile New Program for Decomposing Galaxy Light Profiles
NASA Astrophysics Data System (ADS)
Ciambur, Bogdan C.
2016-12-01
I introduce Profiler, a user-friendly program designed to analyse the radial surface brightness profiles of galaxies. With an intuitive graphical user interface, Profiler can accurately model galaxies of a broad range of morphological types, with various parametric functions routinely employed in the field (Sérsic, core-Sérsic, exponential, Gaussian, Moffat, and Ferrers). In addition to these, Profiler can employ the broken exponential model for disc truncations or anti-truncations, and two special cases of the edge-on disc model: along the disc's major or minor axis. The convolution of (circular or elliptical) models with the point spread function is performed in 2D, and offers a choice between Gaussian, Moffat or a user-provided profile for the point spread function. Profiler is optimised to work with galaxy light profiles obtained from isophotal measurements, which allow for radial gradients in the geometric parameters of the isophotes, and are thus often better at capturing the total light than 2D image-fitting programs. Additionally, the 1D approach is generally less computationally expensive and more stable. I demonstrate Profiler's features by decomposing three case-study galaxies: the cored elliptical galaxy NGC 3348, the nucleated dwarf Seyfert I galaxy Pox 52, and NGC 2549, a double-barred galaxy with an edge-on, truncated disc.
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.
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.
Baran, Richard; Northen, Trent R
2013-10-15
Untargeted metabolite profiling using liquid chromatography and mass spectrometry coupled via electrospray ionization is a powerful tool for the discovery of novel natural products, metabolic capabilities, and biomarkers. However, the elucidation of the identities of uncharacterized metabolites from spectral features remains challenging. A critical step in the metabolite identification workflow is the assignment of redundant spectral features (adducts, fragments, multimers) and calculation of the underlying chemical formula. Inspection of the data by experts using computational tools solving partial problems (e.g., chemical formula calculation for individual ions) can be performed to disambiguate alternative solutions and provide reliable results. However, manual curation is tedious and not readily scalable or standardized. Here we describe an automated procedure for the robust automated mass spectra interpretation and chemical formula calculation using mixed integer linear programming optimization (RAMSI). Chemical rules among related ions are expressed as linear constraints and both the spectra interpretation and chemical formula calculation are performed in a single optimization step. This approach is unbiased in that it does not require predefined sets of neutral losses and positive and negative polarity spectra can be combined in a single optimization. The procedure was evaluated with 30 experimental mass spectra and was found to effectively identify the protonated or deprotonated molecule ([M + H](+) or [M - H](-)) while being robust to the presence of background ions. RAMSI provides a much-needed standardized tool for interpreting ions for subsequent identification in untargeted metabolomics workflows.
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.
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
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.
A farm-level precision land management framework based on integer programming
Li, Qi; Hu, Guiping; Jubery, Talukder Zaki; Ganapathysubramanian, Baskar
2017-01-01
Farmland management involves several planning and decision making tasks including seed selection and irrigation management. A farm-level precision farmland management model based on mixed integer linear programming is proposed in this study. Optimal decisions are designed for pre-season planning of crops and irrigation water allocation. The model captures the effect of size and shape of decision scale as well as special irrigation patterns. The authors illustrate the model with a case study on a farm in the state of California in the U.S. and show the model can capture the impact of precision farm management on profitability. The results show that threefold increase of annual net profit for farmers could be achieved by carefully choosing irrigation and seed selection. Although farmers could increase profits by applying precision management to seed or irrigation alone, profit increase is more significant if farmers apply precision management on seed and irrigation simultaneously. The proposed model can also serve as a risk analysis tool for farmers facing seasonal irrigation water limits as well as a quantitative tool to explore the impact of precision agriculture. PMID:28346499
Poos, Alexandra M; Maicher, André; Dieckmann, Anna K; Oswald, Marcus; Eils, Roland; Kupiec, Martin; Luke, Brian; König, Rainer
2016-06-02
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.
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.
Alvarado, Michelle; Ntaimo, Lewis
2016-09-16
Oncology clinics are often burdened with scheduling large volumes of cancer patients for chemotherapy treatments under limited resources such as the number of nurses and chairs. These cancer patients require a series of appointments over several weeks or months and the timing of these appointments is critical to the treatment's effectiveness. Additionally, the appointment duration, the acuity levels of each appointment, and the availability of clinic nurses are uncertain. The timing constraints, stochastic parameters, rising treatment costs, and increased demand of outpatient oncology clinic services motivate the need for efficient appointment schedules and clinic operations. In this paper, we develop three mean-risk stochastic integer programming (SIP) models, referred to as SIP-CHEMO, for the problem of scheduling individual chemotherapy patient appointments and resources. These mean-risk models are presented and an algorithm is devised to improve computational speed. Computational results were conducted using a simulation model and results indicate that the risk-averse SIP-CHEMO model with the expected excess mean-risk measure can decrease patient waiting times and nurse overtime when compared to deterministic scheduling algorithms by 42 % and 27 %, respectively.
Integer Linear Programming for Constrained Multi-Aspect Committee Review Assignment
Karimzadehgan, Maryam; Zhai, ChengXiang
2011-01-01
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. PMID:22711970
A farm-level precision land management framework based on integer programming.
Li, Qi; Hu, Guiping; Jubery, Talukder Zaki; Ganapathysubramanian, Baskar
2017-01-01
Farmland management involves several planning and decision making tasks including seed selection and irrigation management. A farm-level precision farmland management model based on mixed integer linear programming is proposed in this study. Optimal decisions are designed for pre-season planning of crops and irrigation water allocation. The model captures the effect of size and shape of decision scale as well as special irrigation patterns. The authors illustrate the model with a case study on a farm in the state of California in the U.S. and show the model can capture the impact of precision farm management on profitability. The results show that threefold increase of annual net profit for farmers could be achieved by carefully choosing irrigation and seed selection. Although farmers could increase profits by applying precision management to seed or irrigation alone, profit increase is more significant if farmers apply precision management on seed and irrigation simultaneously. The proposed model can also serve as a risk analysis tool for farmers facing seasonal irrigation water limits as well as a quantitative tool to explore the impact of precision agriculture.
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 further as more functionality is added in the future.
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.
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.
Automated integer programming based separation of arteries and veins from thoracic CT images.
Payer, Christian; Pienn, Michael; Bálint, Zoltán; Shekhovtsov, Alexander; Talakic, Emina; Nagy, Eszter; Olschewski, Andrea; Olschewski, Horst; Urschler, Martin
2016-12-01
Automated computer-aided analysis of lung vessels has shown to yield promising results for non-invasive diagnosis of lung diseases. To detect vascular changes which affect pulmonary arteries and veins differently, both compartments need to be identified. We present a novel, fully automatic method that separates arteries and veins in thoracic computed tomography images, by combining local as well as global properties of pulmonary vessels. We split the problem into two parts: the extraction of multiple distinct vessel subtrees, and their subsequent labeling into arteries and veins. Subtree extraction is performed with an integer program (IP), based on local vessel geometry. As naively solving this IP is time-consuming, we show how to drastically reduce computational effort by reformulating it as a Markov Random Field. Afterwards, each subtree is labeled as either arterial or venous by a second IP, using two anatomical properties of pulmonary vessels: the uniform distribution of arteries and veins, and the parallel configuration and close proximity of arteries and bronchi. We evaluate algorithm performance by comparing the results with 25 voxel-based manual reference segmentations. On this dataset, we show good performance of the subtree extraction, consisting of very few non-vascular structures (median value: 0.9%) and merged subtrees (median value: 0.6%). The resulting separation of arteries and veins achieves a median voxel-based overlap of 96.3% with the manual reference segmentations, outperforming a state-of-the-art interactive method. In conclusion, our novel approach provides an opportunity to become an integral part of computer aided pulmonary diagnosis, where artery/vein separation is important.
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
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.
Large-scale bi-level strain design approaches and mixed-integer programming solution techniques.
Kim, Joonhoon; Reed, Jennifer L; Maravelias, Christos T
2011-01-01
The use of computational models in metabolic engineering has been increasing as more genome-scale metabolic models and computational approaches become available. Various computational approaches have been developed to predict how genetic perturbations affect metabolic behavior at a systems level, and have been successfully used to engineer microbial strains with improved primary or secondary metabolite production. However, identification of metabolic engineering strategies involving a large number of perturbations is currently limited by computational resources due to the size of genome-scale models and the combinatorial nature of the problem. In this study, we present (i) two new bi-level strain design approaches using mixed-integer programming (MIP), and (ii) general solution techniques that improve the performance of MIP-based bi-level approaches. The first approach (SimOptStrain) simultaneously considers gene deletion and non-native reaction addition, while the second approach (BiMOMA) uses minimization of metabolic adjustment to predict knockout behavior in a MIP-based bi-level problem for the first time. Our general MIP solution techniques significantly reduced the CPU times needed to find optimal strategies when applied to an existing strain design approach (OptORF) (e.g., from ∼10 days to ∼5 minutes for metabolic engineering strategies with 4 gene deletions), and identified strategies for producing compounds where previous studies could not (e.g., malate and serine). Additionally, we found novel strategies using SimOptStrain with higher predicted production levels (for succinate and glycerol) than could have been found using an existing approach that considers network additions and deletions in sequential steps rather than simultaneously. Finally, using BiMOMA we found novel strategies involving large numbers of modifications (for pyruvate and glutamate), which sequential search and genetic algorithms were unable to find. The approaches and solution
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.
Cheng, Guanhui; Huang, Guohe; Dong, Cong; Xu, Ye; Chen, Xiujuan; Chen, Jiapei
2017-03-01
Due to the existence of complexities of heterogeneities, hierarchy, discreteness, and interactions in municipal solid waste management (MSWM) systems such as Beijing, China, a series of socio-economic and eco-environmental problems may emerge or worsen and result in irredeemable damages in the following decades. Meanwhile, existing studies, especially ones focusing on MSWM in Beijing, could hardly reflect these complexities in system simulations and provide reliable decision support for management practices. Thus, a framework of distributed mixed-integer fuzzy hierarchical programming (DMIFHP) is developed in this study for MSWM under these complexities. Beijing is selected as a representative case. The Beijing MSWM system is comprehensively analyzed in many aspects such as socio-economic conditions, natural conditions, spatial heterogeneities, treatment facilities, and system complexities, building a solid foundation for system simulation and optimization. Correspondingly, the MSWM system in Beijing is discretized as 235 grids to reflect spatial heterogeneity. A DMIFHP model which is a nonlinear programming problem is constructed to parameterize the Beijing MSWM system. To enable scientific solving of it, a solution algorithm is proposed based on coupling of fuzzy programming and mixed-integer linear programming. Innovations and advantages of the DMIFHP framework are discussed. The optimal MSWM schemes and mechanism revelations will be discussed in another companion paper due to length limitation.
Safikhani, Zhaleh; Sadeghi, Mehdi; Pezeshk, Hamid; Eslahchi, Changiz
2013-01-01
Recent advances in the sequencing technologies have provided a handful of RNA-seq datasets for transcriptome analysis. However, reconstruction of full-length isoforms and estimation of the expression level of transcripts with a low cost are challenging tasks. We propose a novel de novo method named SSP that incorporates interval integer linear programming to resolve alternatively spliced isoforms and reconstruct the whole transcriptome from short reads. Experimental results show that SSP is fast and precise in determining different alternatively spliced isoforms along with the estimation of reconstructed transcript abundances. The SSP software package is available at http://www.bioinf.cs.ipm.ir/software/ssp.
Barnett, Jason; Watson, Jean -Paul; Woodruff, David L.
2016-11-27
Progressive hedging, though an effective heuristic for solving stochastic mixed integer programs (SMIPs), is not guaranteed to converge in this case. Here, we describe BBPH, a branch and bound algorithm that uses PH at each node in the search tree such that, given sufficient time, it will always converge to a globally optimal solution. Additionally, to providing a theoretically convergent “wrapper” for PH applied to SMIPs, computational results demonstrate that for some difficult problem instances branch and bound can find improved solutions after exploring only a few nodes.
Davila, Eric; Chang, Ni-Bin; Diwakaruni, Syamala
2005-06-01
The Lower Rio Grande Valley (LRGV) region in South Texas emerges as a warehouse and transportation center between Central America and the US with positive growth impacts due to the North American Free Trade Agreement (NAFTA). In 10 years time, a 39.8% population increase has resulted in a 25% boost in solid waste per capita disposal rate in the region. A landfill space shortage drives a need for landfill operators to understand their optimal management strategies in this highly-competitive market. Initially, a strategic plan for optimal solid waste pattern distribution minimizes net costs for cities. This is accomplished through a grey integer programming algorithm that encapsulates all uncertainty present in the solid waste system. Secondly, a series of grey integer submodels construct payoff matrices for a zero-sum two-person game. The ensuing game theoretic analysis is critical for evaluating optimal pricing strategies for tipping fees available to the most significant regional landfills (e.g. Browning-Ferris Industries (BFI) and City of Edinburg) as they compete over disposal contracts. The BFI landfill intrinsically benefits from its competitive pricing policy and central location to solid waste generators. The City of Edinburg landfill, on the other hand, wishes to secure its lucrative solid waste management revenue. It desires a gaming strategy backed by optimality that integrates ambiguity in solid waste generation, design capacity boundaries, and unitary shipping costs. Results show that a two-tiered analysis via grey integer programming-based games may pave the way for 'grey Nash equilibria' pricing tactics that will help the Edinburg landfill maintain its waste contracts.
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."
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
NASA Astrophysics Data System (ADS)
Nie, S. L.; Hu, B.; Li, Y. P.; Hu, Z.; Huang, G. H.
2011-03-01
An interval-fuzzy integer nonlinear programming (IFINP) method is developed for the identification of filter allocation and replacement strategies in a fluid power system (FPS) under uncertainty. It can handle uncertainties expressed as interval-fuzzy values that exist in the left- and right-hand sides of constraints as well as in the objective function. The developed method is applied to a case of planning filter allocation and replacement strategies under uncertainty for a FPS with a single circuit. A piecewise linearisation approach is used to convert the nonlinear problem of FPS into a linear one. The generated fuzzy solutions will be used to analyse and interpret the multiple decision alternatives under various system conditions, and thus help decision-makers to make a compromise among the system contamination level, system cost, satisfaction degrees and system-failure risks under different contaminant ingression/generation rates. The results demonstrate that the suction and return filters can effectively reduce the contamination level associated with a low system cost, but the FPS will take lots of failure risk when the contaminant ingression/generation rate is high; and the combination of suction and pressure filters can bring the lowest system cost with more security instead. Furthermore, comparisons for the optimised solutions are made among IFINP, interval-parameter integer nonlinear programming and deterministic linear programming also. Generally, the IFINP method can effectively reduce the total design and operation cost of the filtration system when contaminants ingression/generation rate is high, and it could be extended to the lubricating system.
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)
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.
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.
NASA Astrophysics Data System (ADS)
Zimmermann, Karl-Heinz; Achtziger, Wolfgang
2001-09-01
The size of a systolic array synthesized from a uniform recurrence equation, whose computations are mapped by a linear function to the processors, matches the problem size. In practice, however, there exist several limiting factors on the array size. There are two dual schemes available to derive arrays of smaller size from large-size systolic arrays based on the partitioning of the large-size arrays into subarrays. In LSGP, the subarrays are clustered one-to-one into the processors of a small-size array, while in LPGS, the subarrays are serially assigned to a reduced-size array. In this paper, we propose a common methodology for both LSGP and LPGS based on polyhedral partitionings of large-size k-dimensional systolic arrays which are synthesized from n-dimensional uniform recurrences by linear mappings for allocation and timing. In particular, we address the optimization problem of finding optimal piecewise linear timing functions for small-size arrays. These are mappings composed of linear timing functions for the computations of the subarrays. We study a continuous approximation of this problem by passing from piecewise linear to piecewise quasi-linear timing functions. The resultant problem formulation is then a quadratic programming problem which can be solved by standard algorithms for nonlinear optimization problems.
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.
Lin, Fu; Leyffer, Sven; Munson, Todd
2016-04-12
We study a two-stage mixed-integer linear program (MILP) with more than 1 million binary variables in the second stage. We develop a two-level approach by constructing a semi-coarse model that coarsens with respect to variables and a coarse model that coarsens with respect to both variables and constraints. We coarsen binary variables by selecting a small number of prespecified on/off profiles. We aggregate constraints by partitioning them into groups and taking convex combination over each group. With an appropriate choice of coarsened profiles, the semi-coarse model is guaranteed to find a feasible solution of the original problem and hence providesmore » an upper bound on the optimal solution. We show that solving a sequence of coarse models converges to the same upper bound with proven finite steps. This is achieved by adding violated constraints to coarse models until all constraints in the semi-coarse model are satisfied. We demonstrate the effectiveness of our approach in cogeneration for buildings. Here, the coarsened models allow us to obtain good approximate solutions at a fraction of the time required by solving the original problem. Extensive numerical experiments show that the two-level approach scales to large problems that are beyond the capacity of state-of-the-art commercial MILP solvers.« less
Lin, Fu; Leyffer, Sven; Munson, Todd
2016-04-12
We study a two-stage mixed-integer linear program (MILP) with more than 1 million binary variables in the second stage. We develop a two-level approach by constructing a semi-coarse model that coarsens with respect to variables and a coarse model that coarsens with respect to both variables and constraints. We coarsen binary variables by selecting a small number of prespecified on/off profiles. We aggregate constraints by partitioning them into groups and taking convex combination over each group. With an appropriate choice of coarsened profiles, the semi-coarse model is guaranteed to find a feasible solution of the original problem and hence provides an upper bound on the optimal solution. We show that solving a sequence of coarse models converges to the same upper bound with proven finite steps. This is achieved by adding violated constraints to coarse models until all constraints in the semi-coarse model are satisfied. We demonstrate the effectiveness of our approach in cogeneration for buildings. Here, the coarsened models allow us to obtain good approximate solutions at a fraction of the time required by solving the original problem. Extensive numerical experiments show that the two-level approach scales to large problems that are beyond the capacity of state-of-the-art commercial MILP solvers.
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
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.
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/.
Melas, Ioannis N; Samaga, Regina; Alexopoulos, Leonidas G; Klamt, Steffen
2013-01-01
Cross-referencing experimental data with our current knowledge of signaling network topologies is one central goal of mathematical modeling of cellular signal transduction networks. We present a new methodology for data-driven interrogation and training of signaling networks. While most published methods for signaling network inference operate on Bayesian, Boolean, or ODE models, our approach uses integer linear programming (ILP) on interaction graphs to encode constraints on the qualitative behavior of the nodes. These constraints are posed by the network topology and their formulation as ILP allows us to predict the possible qualitative changes (up, down, no effect) of the activation levels of the nodes for a given stimulus. We provide four basic operations to detect and remove inconsistencies between measurements and predicted behavior: (i) find a topology-consistent explanation for responses of signaling nodes measured in a stimulus-response experiment (if none exists, find the closest explanation); (ii) determine a minimal set of nodes that need to be corrected to make an inconsistent scenario consistent; (iii) determine the optimal subgraph of the given network topology which can best reflect measurements from a set of experimental scenarios; (iv) find possibly missing edges that would improve the consistency of the graph with respect to a set of experimental scenarios the most. We demonstrate the applicability of the proposed approach by interrogating a manually curated interaction graph model of EGFR/ErbB signaling against a library of high-throughput phosphoproteomic data measured in primary hepatocytes. Our methods detect interactions that are likely to be inactive in hepatocytes and provide suggestions for new interactions that, if included, would significantly improve the goodness of fit. Our framework is highly flexible and the underlying model requires only easily accessible biological knowledge. All related algorithms were implemented in a freely
Alexopoulos, Leonidas G.; Klamt, Steffen
2013-01-01
Cross-referencing experimental data with our current knowledge of signaling network topologies is one central goal of mathematical modeling of cellular signal transduction networks. We present a new methodology for data-driven interrogation and training of signaling networks. While most published methods for signaling network inference operate on Bayesian, Boolean, or ODE models, our approach uses integer linear programming (ILP) on interaction graphs to encode constraints on the qualitative behavior of the nodes. These constraints are posed by the network topology and their formulation as ILP allows us to predict the possible qualitative changes (up, down, no effect) of the activation levels of the nodes for a given stimulus. We provide four basic operations to detect and remove inconsistencies between measurements and predicted behavior: (i) find a topology-consistent explanation for responses of signaling nodes measured in a stimulus-response experiment (if none exists, find the closest explanation); (ii) determine a minimal set of nodes that need to be corrected to make an inconsistent scenario consistent; (iii) determine the optimal subgraph of the given network topology which can best reflect measurements from a set of experimental scenarios; (iv) find possibly missing edges that would improve the consistency of the graph with respect to a set of experimental scenarios the most. We demonstrate the applicability of the proposed approach by interrogating a manually curated interaction graph model of EGFR/ErbB signaling against a library of high-throughput phosphoproteomic data measured in primary hepatocytes. Our methods detect interactions that are likely to be inactive in hepatocytes and provide suggestions for new interactions that, if included, would significantly improve the goodness of fit. Our framework is highly flexible and the underlying model requires only easily accessible biological knowledge. All related algorithms were implemented in a freely
Cheng, Guanhui; Huang, Guohe; Dong, Cong; Xu, Ye; Chen, Jiapei; Chen, Xiujuan; Li, Kailong
2017-02-16
As presented in the first companion paper, distributed mixed-integer fuzzy hierarchical programming (DMIFHP) was developed for municipal solid waste management (MSWM) under complexities of heterogeneities, hierarchy, discreteness, and interactions. Beijing was selected as a representative case. This paper focuses on presenting the obtained schemes and the revealed mechanisms of the Beijing MSWM system. The optimal MSWM schemes for Beijing under various solid waste treatment policies and their differences are deliberated. The impacts of facility expansion, hierarchy, and spatial heterogeneities and potential extensions of DMIFHP are also discussed. A few of findings are revealed from the results and a series of comparisons and analyses. For instance, DMIFHP is capable of robustly reflecting these complexities in MSWM systems, especially for Beijing. The optimal MSWM schemes are of fragmented patterns due to the dominant role of the proximity principle in allocating solid waste treatment resources, and they are closely related to regulated ratios of landfilling, incineration, and composting. Communities without significant differences among distances to different types of treatment facilities are more sensitive to these ratios than others. The complexities of hierarchy and heterogeneities pose significant impacts on MSWM practices. Spatial dislocation of MSW generation rates and facility capacities caused by unreasonable planning in the past may result in insufficient utilization of treatment capacities under substantial influences of transportation costs. The problems of unreasonable MSWM planning, e.g., severe imbalance among different technologies and complete vacancy of ten facilities, should be gained deliberation of the public and the municipal or local governments in Beijing. These findings are helpful for gaining insights into MSWM systems under these complexities, mitigating key challenges in the planning of these systems, improving the related management
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
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…
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.
Zou, Meng; Zhang, Peng-Jun; Wen, Xin-Yu; Chen, Luonan; Tian, Ya-Ping; Wang, Yong
2015-07-15
Multi-biomarker panels can capture the nonlinear synergy among biomarkers and they are important to aid in the early diagnosis and ultimately battle complex diseases. However, identification of these multi-biomarker panels from case and control data is challenging. For example, the exhaustive search method is computationally infeasible when the data dimension is high. Here, we propose a novel method, MILP_k, to identify serum-based multi-biomarker panel to distinguish colorectal cancers (CRC) from benign colorectal tumors. Specifically, the multi-biomarker panel detection problem is modeled by a mixed integer programming to maximize the classification accuracy. Then we measured the serum profiling data for 101 CRC patients and 95 benign patients. The 61 biomarkers were analyzed individually and further their combinations by our method. We discovered 4 biomarkers as the optimal small multi-biomarker panel, including known CRC biomarkers CEA and IL-10 as well as novel biomarkers IMA and NSE. This multi-biomarker panel obtains leave-one-out cross-validation (LOOCV) accuracy to 0.7857 by nearest centroid classifier. An independent test of this panel by support vector machine (SVM) with threefold cross validation gets an AUC 0.8438. This greatly improves the predictive accuracy by 20% over the single best biomarker. Further extension of this 4-biomarker panel to a larger 13-biomarker panel improves the LOOCV to 0.8673 with independent AUC 0.8437. Comparison with the exhaustive search method shows that our method dramatically reduces the searching time by 1000-fold. Experiments on the early cancer stage samples reveal two panel of biomarkers and show promising accuracy. The proposed method allows us to select the subset of biomarkers with best accuracy to distinguish case and control samples given the number of selected biomarkers. Both receiver operating characteristic curve and precision-recall curve show our method's consistent performance gain in accuracy. Our method
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.
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
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
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.
Variable Expansion Techniques for Decomposable Optimization Problems
2011-03-05
meration or dynamic programming. Recall the edge partition problem studied by Taskin et al. above in reference 7. (Z. Caner Taskin was supported by the...Stochastic Integer Program- ming, August 2009 August 2009. 12 2. Z. Caner Taskin, Algorithms for Solving Multi-Level Optimization Problems with Dis
1980-05-31
Multiconstraint Zero - One Knapsack Problem ," The Journal of the Operational Research Society, Vol. 30, 1979, pp. 369-378. 69 [41] Kepler, C...programming. Shih [401 has written on a branch and bound method , Kepler and Blackman [41] have demonstrated the use of dynamic programming in the selection of...Portfolio Selection Model," IEEE A. Transactions on Engineering Management, Vol. EM-26, No. 1, 1979, pp. 2-7. [40] Shih, Wei, "A Branch and
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
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.
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…
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.
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.
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.
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.
Examining the decomposed brain.
MacKenzie, James Mackintosh
2014-12-01
Examination of the decomposed brain is a largely neglected area of forensic neuropathology. However, careful examination often yields valuable information that may assist in criminal proceedings. Decomposition encompasses the processes of autolysis, putrefaction, and decay. Most decomposed brains will be affected by both autolysis and putrefaction, resulting in a brain that may, at one end of the spectrum, be almost normal or, at the other end, pulpified, depending on the conditions in which the body remained after death and the postmortem interval. Naked eye examination may detect areas of hemorrhage and also guides appropriate sampling for histology. Histological appearances are often better than what would be predicted from the state of the brain. Histology often confirms macroscopic abnormalities and may also reveal other features such as ischemic injury. Silver staining demonstrates neuritic plaques, and immunocytochemistry for β-amyloid precursor protein and other molecules produces results comparable with those seen in well-preserved fixed brains. The usefulness of information derived from the examination of the decomposed brain in criminal proceedings is illustrated with 6 case reports drawn from the author's own practice.
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)
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.
Modelling with Integer Variables.
1984-01-01
H. Korte, North-Holland Publishing Co., Amsterdam, pp. 3-53, 1979. 2. Bazaraa , M. and Shetty, M., Non-Linear Programming, John Wiley & Sons, Inc., New...Survey," SIAM Review 18 (1976), pp. 710-760. 5. Bazaraa , M. and Shetty, M., Non-Linear Programming, John Wiley & Sons, Inc., New York 1979. 6. Beale
Trace of totally positive algebraic integers and integer transfinite diameter
NASA Astrophysics Data System (ADS)
Flammang, V.
2009-06-01
Explicit auxiliary functions can be used in the ``Schur-Siegel- Smyth trace problem''. In the previous works, these functions were constructed only with polynomials having all their roots positive. Here, we use several polynomials with complex roots, which are found with Wu's algorithm, and we improve the known lower bounds for the absolute trace of totally positive algebraic integers. This improvement has a consequence for the search of Salem numbers that have a negative trace. The same method also gives a small improvement of the upper bound for the integer transfinite diameter of [0,1].
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.
MISO - Mixed Integer Surrogate Optimization
Mueller, Juliane
2016-01-20
MISO is an optimization framework for solving computationally expensive mixed-integer, black-box, global optimization problems. MISO uses surrogate models to approximate the computationally expensive objective function. Hence, derivative information, which is generally unavailable for black-box simulation objective functions, is not needed. MISO allows the user to choose the initial experimental design strategy, the type of surrogate model, and the sampling strategy.
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…
Catalytic cartridge SO3 decomposer
Galloway, T.R.
1982-05-25
A catalytic cartridge surrounding a heat pipe driven by a heat source is utilized as a SO3 decomposer for thermochemical hydrogen production. The cartridge has two embodiments, a crossflow cartridge and an axial flow cartridge. In the cross-flow cartridge, SO3 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 axialflow cartridge, so3 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.
Prospective Elementary Teachers' Conceptual Understanding of Integers
ERIC Educational Resources Information Center
Reeder, Stacy; Bateiha, Summer
2016-01-01
This investigation examined the degree to which prospective elementary teachers had developed a meaningful and conceptual understanding of what integers are and explored their development of models for multiplication with integers that are related to everyday activities. Additionally, this study explored how these understandings informed…
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…
Effective integer-to-integer transforms for JPEG2000 coder
NASA Astrophysics Data System (ADS)
Przelaskowski, Artur
2001-12-01
This paper considers reversible transforms which are used in wavelet compression according to nowadays JPEG2000 standard. Original data decomposition in a form of integer wavelet transformation realized in subband decomposition scheme is optimized by design and selection of the most effective transforms. Lifting scheme is used to construct new biorthogonal symmetric wavelets. Number and distribution of vanishing moments, subband coding gain, associated filter length, computational complexity and number of lifting steps were mainly analyzed in the optimization of designed transforms. Coming from many tests of compression efficiency evaluation in JPEG2000 standardization process, the best selected transforms have been compared to designed ones to conclude the most efficient for compression wavelet bases and their important features. Certain new transforms overcome all other in both phases of lossy-to-lossless compression (e.g. up to 0.5 dB of PSNR for 0.5 bpp in comparison to the state-of-art transforms of JPEG2000 compression, and up to 3dB over 5/3 standard reversible transform). Moreover, the lossy compression efficiency of proposed reversible wavelets is comparable to reference irreversible wavelets potential in several cases. The highest improvement over that reference PSNR values is close to 1.2 dB.
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.
RSM 1.0 - A RESUPPLY SCHEDULER USING INTEGER OPTIMIZATION
NASA Technical Reports Server (NTRS)
Viterna, L. A.
1994-01-01
RSM, Resupply Scheduling Modeler, is a fully menu-driven program that uses integer programming techniques to determine an optimum schedule for replacing components on or before the end of a fixed replacement period. Although 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. RSM 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 computationally intensive, integer programming was required for accuracy when modeling systems with small quantities of components. Input values for component life cane be real numbers, RSM converts them to integers by dividing the lifetime by the period duration, then reducing the result to the next lowest integer. For each component, there is a set of constraints that insure that it is replaced before its lifetime expires. RSM includes user-defined constraints such as transportation mass and volume limits, as well as component life, available repair crew time and assembly sequences. A weighting factor allows the program to minimize factors such as cost. The program then performs an iterative analysis, which is displayed during the processing. A message gives the first period in which resources are being exceeded on each iteration. If the scheduling problem is unfeasible, the final message will also indicate the first period in which resources were exceeded. RSM is written in APL2 for IBM PC series computers and compatibles. A stand-alone executable version of RSM is provided; however, this is a "packed" version of RSM which can only utilize the memory within the 640K DOS limit. This executable requires at least 640K of memory and DOS 3.1 or higher. Source code for an APL2/PC workspace version is also provided. This version of RSM can make full use of any
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.
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
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…
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
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.
Elementary Theory of Factoring Trinomials with Integer Coefficients over the Integers
ERIC Educational Resources Information Center
Donnell, William A.
2010-01-01
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…
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…
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.
A Binomial Integer-Valued ARCH Model.
Ristić, Miroslav M; Weiß, Christian H; Janjić, Ana D
2016-11-01
We present an integer-valued ARCH model which can be used for modeling time series of counts with under-, equi-, or overdispersion. The introduced model has a conditional binomial distribution, and it is shown to be strictly stationary and ergodic. The unknown parameters are estimated by three methods: conditional maximum likelihood, conditional least squares and maximum likelihood type penalty function estimation. The asymptotic distributions of the estimators are derived. A real application of the novel model to epidemic surveillance is briefly discussed. Finally, a generalization of the introduced model is considered by introducing an integer-valued GARCH model.
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
Integer sequence discovery from small graphs
Hoppe, Travis; Petrone, Anna
2015-01-01
We have exhaustively enumerated all simple, connected graphs of a finite order and have computed a selection of invariants over this set. Integer sequences were constructed from these invariants and checked against the Online Encyclopedia of Integer Sequences (OEIS). 141 new sequences were added and six sequences were extended. From the graph database, we were able to programmatically suggest relationships among the invariants. It will be shown that we can readily visualize any sequence of graphs with a given criteria. The code has been released as an open-source framework for further analysis and the database was constructed to be extensible to invariants not considered in this work. PMID:27034526
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…
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.
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.
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.
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)
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…
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.
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)
Jazaeri, S.; Amiri-Simkooei, A. R.; Sharifi, M. A.
2012-02-01
GNSS ambiguity resolution is the key issue in the high-precision relative geodetic positioning and navigation applications. It is a problem of integer programming plus integer quality evaluation. Different integer search estimation methods have been proposed for the integer solution of ambiguity resolution. Slow rate of convergence is the main obstacle to the existing methods where tens of ambiguities are involved. Herein, integer search estimation for the GNSS ambiguity resolution based on the lattice theory is proposed. It is mathematically shown that the closest lattice point problem is the same as the integer least-squares (ILS) estimation problem and that the lattice reduction speeds up searching process. We have implemented three integer search strategies: Agrell, Eriksson, Vardy, Zeger (AEVZ), modification of Schnorr-Euchner enumeration (M-SE) and modification of Viterbo-Boutros enumeration (M-VB). The methods have been numerically implemented in several simulated examples under different scenarios and over 100 independent runs. The decorrelation process (or unimodular transformations) has been first used to transform the original ILS problem to a new one in all simulations. We have then applied different search algorithms to the transformed ILS problem. The numerical simulations have shown that AEVZ, M-SE, and M-VB are about 320, 120 and 50 times faster than LAMBDA, respectively, for a search space of dimension 40. This number could change to about 350, 160 and 60 for dimension 45. The AEVZ is shown to be faster than MLAMBDA by a factor of 5. Similar conclusions could be made using the application of the proposed algorithms to the real GPS data.
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.
Finding community structures in complex networks using mixed integer optimisation
NASA Astrophysics Data System (ADS)
Xu, G.; Tsoka, S.; Papageorgiou, L. G.
2007-11-01
The detection of community structure has been used to reveal the relationships between individual objects and their groupings in networks. This paper presents a mathematical programming approach to identify the optimal community structures in complex networks based on the maximisation of a network modularity metric for partitioning a network into modules. The overall problem is formulated as a mixed integer quadratic programming (MIQP) model, which can then be solved to global optimality using standard optimisation software. The solution procedure is further enhanced by developing special symmetry-breaking constraints to eliminate equivalent solutions. It is shown that additional features such as minimum/maximum module size and balancing among modules can easily be incorporated in the model. The applicability of the proposed optimisation-based approach is demonstrated by four examples. Comparative results with other approaches from the literature show that the proposed methodology has superior performance while global optimum is guaranteed.
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…
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.
Catalytic cartridge SO/sub 3/ decomposer
Galloway, T.R.
1980-11-18
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. A fusion reactor may be used as the heat source.
Catalytic cartridge SO/sub 3/ decomposer
Galloway, T.R.
1982-09-28
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.
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
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 links
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
Corrosion and repairs of ammonium carbamate decomposers
De Romero, M.F.; Galban, J.P.
1996-05-01
Corrosion-erosion problems occurred in the carbon steel base metal of the ammonium carbamate decomposers in an urea extraction process lined with type 316L (UNS S31603) urea grade stainless steel. The cladding was replaced by weld overlay using a semiautomatic gas metal arc welding process. The first layer was alloy 25%Cr-15%Ni-2%Mo (UNS W30923); the second layer was alloy 25%Cr-22%Ni-2%Mo (UNS W31020).
A Computer Program for the Staircase Integer Programming Problem.
1980-07-01
output. If termination occurs normally, the final section of output contains the optimum solution and its objective value. The solution is printed in 2015 ...J8UUNU = JFUUND / 2 IF ((J8O’JND + ISI7MC) .GT. rNCVAL) GO TO 3900 %?1kFU. ?IRA401 UP ON Y(1) 11)1.: = -1 NIF ?4P1 = IPART(I) + I ’Tn 3700 ,6A P W
Integer Quantum Hall Effect in Trilayer Graphene
NASA Astrophysics Data System (ADS)
Kumar, A.; Escoffier, W.; Poumirol, J. M.; Faugeras, C.; Arovas, D. P.; Fogler, M. M.; Guinea, F.; Roche, S.; Goiran, M.; Raquet, B.
2011-09-01
By using high-magnetic fields (up to 60 T), we observe compelling evidence of the integer quantum Hall effect in trilayer graphene. The magnetotransport fingerprints are similar to those of the graphene monolayer, except for the absence of a plateau at a filling factor of ν=2. At a very low filling factor, the Hall resistance vanishes due to the presence of mixed electron and hole carriers induced by disorder. The measured Hall resistivity plateaus are well reproduced theoretically, using a self-consistent Hartree calculations of the Landau levels and assuming an ABC stacking order of the three layers.
Fast Integer Ambiguity Resolution for GPS Attitude Determination
NASA Technical Reports Server (NTRS)
Lightsey, E. Glenn; Crassidis, John L.; Markley, F. Landis
1999-01-01
In this paper, a new algorithm for GPS (Global Positioning System) integer ambiguity resolution is shown. The algorithm first incorporates an instantaneous (static) integer search to significantly reduce the search space using a geometric inequality. Then a batch-type loss function is used to check the remaining integers in order to determine the optimal integer. This batch function represents the GPS sightline vectors in the body frame as the sum of two vectors, one depending on the phase measurements and the other on the unknown integers. The new algorithm has several advantages: 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 resolve the integers even when coplanar baselines exist. The performance of the new algorithm is tested on a dynamic hardware simulator.
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.
Can statistical learning bootstrap the integers?
Rips, Lance J; Asmuth, Jennifer; Bloomfield, Amber
2013-09-01
This paper examines Piantadosi, Tenenbaum, and Goodman's (2012) model for how children learn the relation between number words ("one" through "ten") and cardinalities (sizes of sets with one through ten elements). This model shows how statistical learning can induce this relation, reorganizing its procedures as it does so in roughly the way children do. We question, however, Piantadosi et al.'s claim that the model performs "Quinian bootstrapping," in the sense of Carey (2009). Unlike bootstrapping, the concept it learns is not discontinuous with the concepts it starts with. Instead, the model learns by recombining its primitives into hypotheses and confirming them statistically. As such, it accords better with earlier claims (Fodor, 1975, 1981) that learning does not increase expressive power. We also question the relevance of the simulation for children's learning. The model starts with a preselected set of15 primitives, and the procedure it learns differs from children's method. Finally, the partial knowledge of the positive integers that the model attains is consistent with an infinite number of nonstandard meanings-for example, that the integers stop after ten or loop from ten back to one.
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.
An experiment on Lowest Unique Integer Games
NASA Astrophysics Data System (ADS)
Yamada, Takashi; Hanaki, Nobuyuki
2016-12-01
We experimentally study Lowest Unique Integer Games (LUIGs) to determine if and how subjects self-organize into different behavioral classes. In a LUIG, N(≥ 3) players submit a positive integer up to M and the player choosing the smallest number not chosen by anyone else wins. LUIGs are simplified versions of real systems such as Lowest/Highest Unique Bid Auctions that have been attracting attention from scholars, yet experimental studies are scarce. Furthermore, LUIGs offer insights into choice patterns that can shed light on the alleviation of congestion problems. Here, we consider four LUIGs with N = { 3 , 4 } and M = { 3 , 4 } . We find that (a) choices made by more than 1/3 of subjects were not significantly different from what a symmetric mixed-strategy Nash equilibrium (MSE) predicts; however, (b) subjects who behaved significantly differently from what the MSE predicts won the game more frequently. What distinguishes subjects was their tendencies to change their choices following losses.
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.
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.
Statistical Mechanical Models of Integer Factorization Problem
NASA Astrophysics Data System (ADS)
Nakajima, Chihiro H.; Ohzeki, Masayuki
2017-01-01
We formulate the integer factorization problem via a formulation of the searching problem for the ground state of a statistical mechanical Hamiltonian. The first passage time required to find a correct divisor of a composite number signifies the exponential computational hardness. The analysis of the density of states of two macroscopic quantities, i.e., the energy and the Hamming distance from the correct solutions, leads to the conclusion that the ground state (correct solution) is completely isolated from the other low-energy states, with the distance being proportional to the system size. In addition, the profile of the microcanonical entropy of the model has two peculiar features that are each related to two marked changes in the energy region sampled via Monte Carlo simulation or simulated annealing. Hence, we find a peculiar first-order phase transition in our model.
DCMDSM: a DICOM decomposed storage model
Savaris, Alexandre; Härder, Theo; von Wangenheim, Aldo
2014-01-01
Objective To design, build, and evaluate a storage model able to manage heterogeneous digital imaging and communications in medicine (DICOM) images. The model must be simple, but flexible enough to accommodate variable content without structural modifications; must be effective on answering query/retrieval operations according to the DICOM standard; and must provide performance gains on querying/retrieving content to justify its adoption by image-related projects. Methods The proposal adapts the original decomposed storage model, incorporating structural and organizational characteristics present in DICOM image files. Tag values are stored according to their data types/domains, in a schema built on top of a standard relational database management system (RDBMS). Evaluation includes storing heterogeneous DICOM images, querying metadata using a variable number of predicates, and retrieving full-content images for different hierarchical levels. Results and discussion When compared to a well established DICOM image archive, the proposal is 0.6–7.2 times slower in storing content; however, in querying individual tags, it is about 48.0% faster. In querying groups of tags, DICOM decomposed storage model (DCMDSM) is outperformed in scenarios with a large number of tags and low selectivity (being 66.5% slower); however, when the number of tags is balanced with better selectivity predicates, the performance gains are up to 79.1%. In executing full-content retrieval, in turn, the proposal is about 48.3% faster. Conclusions DCMDSM is a model built for the storage of heterogeneous DICOM content, based on a straightforward database design. The results obtained through its evaluation attest its suitability as a storage layer for projects where DICOM images are stored once, and queried/retrieved whenever necessary. PMID:24491269
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.
Optimizing Non-Decomposable Loss Functions in Structured Prediction
Ranjbar, Mani; Lan, Tian; Wang, Yang; Robinovitch, Steven N.; Li, Ze-Nian; Mori, Greg
2012-01-01
We develop an algorithm for structured prediction with non-decomposable performance measures. The algorithm learns parameters of Markov random fields and can be applied to multivariate performance measures. Examples include performance measures such as Fβ score (natural language processing), intersection over union (object category segmentation), Precision/Recall at k (search engines) and ROC area (binary classifiers). We attack this optimization problem by approximating the loss function with a piecewise linear function. The loss augmented inference forms a quadratic program (QP), which we solve using LP relaxation. We apply this approach to two tasks: object class-specific segmentation and human action retrieval from videos. We show significant improvement over baseline approaches that either use simple loss functions or simple scoring functions on the PASCAL VOC and H3D Segmentation datasets, and a nursing home action recognition dataset. PMID:22868650
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)
Discrete Dirac equation on a finite half-integer lattice
NASA Technical Reports Server (NTRS)
Smalley, L. L.
1986-01-01
The formulation of the Dirac equation on a discrete lattice with half-integer spacing and periodic boundary conditions is investigated analytically. The importance of lattice formulations for problems in field theory and quantum mechanics is explained; the concept of half-integer Fourier representation is introduced; the discrete Dirac equation for the two-dimensional case is derived; dispersion relations for the four-dimensional case are developed; and the spinor formulation for the Dirac fields on the half-integer lattice and the discrete time variable for the four-dimensional time-dependent Dirac equation are obtained. It is argued that the half-integer lattice, because it takes the Dirac Lagrangian into account, is more than a mere relabeling of the integer lattice and may have fundamental physical meaning (e.g., for the statistics of fermions). It is noted that the present formulation does not lead to species doubling, except in the continuum limit.
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
Cosmological constraints on a decomposed Chaplygin gas
NASA Astrophysics Data System (ADS)
Wang, Yuting; Wands, David; Xu, Lixin; De-Santiago, Josue; Hojjati, Alireza
2013-04-01
Any unified dark matter cosmology can be decomposed into dark matter interacting with vacuum energy, without introducing any additional degrees of freedom. We present observational constraints on an interacting vacuum plus dark energy corresponding to a generalized Chaplygin gas cosmology. We consider two distinct models for the interaction leading to either a barotropic equation of state or dark matter that follows geodesics, corresponding to a rest-frame sound speed equal to the adiabatic sound speed or zero sound speed, respectively. For the barotropic model, the most stringent constraint on α comes from the combination of CMB+SNIa+LSS(m) gives α<5.66×10-6 at the 95% confidence level, which indicates that the barotropic model must be extremely close to the ΛCDM cosmology. For the case where the dark matter follows geodesics, perturbations have zero sound speed, and CMB+SNIa+gISW then gives the much weaker constraint -0.15<α<0.26 at the 95% confidence level.
VOC Emissions From Decomposing Leaf Litter
NASA Astrophysics Data System (ADS)
Brown, E. M.; Wilkinson, M. J.; Fierer, N.; Monson, R. K.
2007-12-01
The emission of VOCs from the biosphere has a profound effect on the oxidative capacity of the troposphere. Most studies of the flux of reactive carbon from the biosphere have focused on BVOC emissions at leaf and canopy scales with relatively few studies investigating BVOC emissions from soils. Here we present results describing the emissions of a suite of BVOCs from different litter types under different levels of nitrogen availability. To investigate these effects, three biochemically distinct litter types (Deschampsia sp., Acomostylis sp., and Rhododendron sp.) were coarsely ground and incubated in the dark for two months under different nitrogen regimes at optimal conditions for microbial activity. We used proton transfer reaction mass spectrometry and an infrared gas analyzer (IRGA) to monitor BVOC emissions and CO2 production rates throughout the course of the investigation. When different leaf litter types decomposed, they released distinctly different types and quantities of VOCs. However, varying nitrogen availability caused the VOC signature from some litters to change dramatically. We suggest that decomposition of leaf litter could provide a substantive source of reactive carbon to the atmosphere at local and regional scales and hypothesize that nitrogen deposition may play a role in attenuating the release of some reactive species.
Decomposer animals and bioremediation of soils.
Haimi, J
2000-02-01
Although microorganisms are degrading the contaminants in bioremediation processes, soil animals can also have important--while usually an indirect--role in these processes. Soil animals are useful indicators of soil contamination, both before and after the bioremediation. Many toxicity and bioavailability assessment methods utilizing soil animals have been developed for hazard and risk-assessment procedures. Not only the survival of the animals, but also more sensitive parameters like growth, reproduction and community structure have often been taken into account in the assessment. The use of bioassays together with chemical analyses gives the most reliable results for risk analyses. This is because physical, chemical and biological properties of the remediated soil may be changed during the process, and it is possible that transformation rather than mineralization of the contaminants has taken place. In addition, the soil may contain other harmful substances than those searched in chemical analyses. Finally, because the ultimate goal of the bioremediation should be--together with mineralization of the harmful substances--the ecological recovery of the soil, development of diverse decomposer community as a basis of the functioning ecosystem should be ensured. Soil animals, especially the large ones, can also actively take part in the ecological recovery processes through their own activity. The potential risk of transfer of contaminants accumulated in soil animals to the above-ground food webs should be borne in mind.
Integer lattice dynamics for Vlasov-Poisson
NASA Astrophysics Data System (ADS)
Mocz, Philip; Succi, Sauro
2017-03-01
We revisit the integer lattice (IL) method to numerically solve the Vlasov-Poisson equations, and show that a slight variant of the method is a very easy, viable, and efficient numerical approach to study the dynamics of self-gravitating, collisionless systems. The distribution function lives in a discretized lattice phase-space, and each time-step in the simulation corresponds to a simple permutation of the lattice sites. Hence, the method is Lagrangian, conservative, and fully time-reversible. IL complements other existing methods, such as N-body/particle mesh (computationally efficient, but affected by Monte Carlo sampling noise and two-body relaxation) and finite volume (FV) direct integration schemes (expensive, accurate but diffusive). We also present improvements to the FV scheme, using a moving-mesh approach inspired by IL, to reduce numerical diffusion and the time-step criterion. Being a direct integration scheme like FV, IL is memory limited (memory requirement for a full 3D problem scales as N6, where N is the resolution per linear phase-space dimension). However, we describe a new technique for achieving N4 scaling. The method offers promise for investigating the full 6D phase-space of collisionless systems of stars and dark matter.
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.
Footstep Planning on Uneven Terrain with Mixed-Integer Convex Optimization
2014-08-01
infocenter/cosinfoc/v12r2/topic/com.ibm. common.doc/doc/banner.htm [18] “ GNU linear programming kit.” [Online]. Available: http://www.gnu. org/software...planning footstep placements for a robot walking on uneven terrain with obsta- cles, using a mixed-integer quadratically-constrained quadratic program ...CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING
A review of «integer PPP» applications
NASA Astrophysics Data System (ADS)
Perosanz, Felix; Mercier, Flavien; Loyer, Sylvain; Petit, Gérard; Marty, Jean-Charles
2016-04-01
The possibility of fixing GNSS phase observations to integer values in PPP mode has been demonstrated by several authors. Various scientific and commercial services have started offering this option. In this presentation we first summarize the mathematical formalism needed to recover integer ambiguities while processing un-differenced GNSS phase observations. The improvements but also the limitations of "integer PPP" (IPPP) solutions are discussed. Then we make a review of several scientific results based on this method to illustrate its wide field of applications like oceanic buoy tracking, glacier deformation, atomic oscillator frequency transfer, LEO satellite orbit determination. Several ideas for future improvement are also discussed including the recommendation to IGS Analysis Centers to adopt a compatible approach to deliver "integer" clock products for a combined solution that would allow for IPPP solutions.
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…
Increased decomposer diversity accelerates and potentially stabilises litter decomposition.
Kitz, Florian; Steinwandter, Michael; Traugott, Michael; Seeber, Julia
2015-04-01
Little is known about the effect of decomposer diversity on litter decomposition in alpine areas. Especially under the premise that alpine ecosystems are very sensitive to global change and are currently undergoing extensive land-use changes, a better understanding is needed to predict how environmental change will affect litter decomposition. A mesocosm experiment was conducted to compare the effects of the most common and functionally diverse invertebrates (earthworms, millipedes and sciarid larvae) found in alpine soils on decomposition rates and to assess how decomposer diversity affects litter decomposition. Experimental and estimated (i.e. projected to field decomposer-biomass) litter mass loss was 13-33% higher in the three-species treatment. Notably, the variability in decomposition was greatly reduced when decomposer diversity was high, indicating a portfolio effect. Our results suggest that invertebrate decomposer diversity is essential for sustaining litter decomposition in alpine areas and for the stability of this service.
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.
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.
An Integer Program Decomposition Approach to Combat Planning.
1998-09-01
appear in IEEE Transactions in November 1998), July 1998. 68. Ozdamar, Linet and Giindiiz Ulusoy . "A Local Constraint Based Analysis Approach to Project...Scheduling under General Resource Constraints," European Journal of Operational Research, 79:287-298 (1994). 69. Ozdamar, Linet and Giindiiz Ulusoy . "A
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. 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.
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.
NASA Astrophysics Data System (ADS)
Masrour, R.; Jabar, A.; Bahmad, L.; Hamedoun, M.; Benyoussef, A.
2017-01-01
In this paper, we study the magnetic properties of ferrimagnetic mixed spins with integer σ = 2 and half-integer S = 7 / 2 in a Blume-Capel model, using Monte Carlo simulations. The considered Hamiltonian includes the first nearest-neighbors and the exchange coupling interactions on the two sub-lattices. The effect of these coupling exchange interactions, in the presence of both the external magnetic field and the crystal field, are studied. The magnetizations and the corresponding susceptibilities are presented and discussed. Finally, we have interpreted the behaviors of the magnetic hysteresis of this model.
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…
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…
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…
More Designer Decimals: The Integers and Their Geometric Extensions
ERIC Educational Resources Information Center
Chan, O-Yeat; Smoak, James
2006-01-01
The fraction 10000/9801 has an intriguing decimal expansion, namely 1.02030405... In this paper, we investigate the properties of this fraction via an arithmetical approach. The approach also yields a class of fractions whose decimal expansions involve higher-dimensional analogues of the integers, the n-dimensional pyramidal numbers, thereby…
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.
A fast DFT algorithm using complex integer transforms
NASA Technical Reports Server (NTRS)
Reed, I. S.; Truong, T. K.
1978-01-01
Winograd's algorithm for computing the discrete Fourier transform is extended considerably for certain large transform lengths. This is accomplished by performing the cyclic convolution, required by Winograd's method, by a fast transform over certain complex integer fields. This algorithm requires fewer multiplications than either the standard fast Fourier transform or Winograd's more conventional algorithms.
Factoring integers with Young's N-slit interferometer
NASA Astrophysics Data System (ADS)
Clauser, John F.; Dowling, Jonathan P.
1996-06-01
We show that a Young's N-slit interferometer can be used to factor the integer N. The device could factor four- or five-digit numbers in a practical fashion. This work shows how number theory may arise in physical problems, and may provide some insight as to how quantum computers can carry out factoring problems by interferometric means.
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…
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…
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…
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…
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.
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.
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…
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.
Producer-decomposer co-dependency influences biodiversity effects.
Naeem, S; Hahn, D R; Schuurman, G
2000-02-17
Producers, such as plants and algae, acquire nutrients from inorganic sources that are supplied primarily by decomposers whereas decomposers, mostly fungi and bacteria, acquire carbon from organic sources that are supplied primarily by producers. This producer-decomposer co-dependency is important in governing ecosystem processes, which implies that the impacts of declining biodiversity on ecosystem functioning should be strongly influenced by this process. Here we show, by simultaneously manipulating producer (green algal) and decomposer (heterotrophic bacterial) diversity in freshwater microcosms, that algal biomass production varies considerably among microcosms (0.0-0.67 mg ml(-1)), but that neither algal nor bacterial diversity by itself can explain this variation. Instead, production is a joint function of both algal and bacterial diversity. Furthermore, the range in algal production in microscosms in which bacterial diversity was manipulated was nearly double (1.82 times) that of microcosms in which bacterial diversity was not manipulated. Measures of organic carbon use by bacteria in these microcosms indicate that carbon usage is the mechanism responsible for these results. Because both producer and microbial diversity respond to disturbance and habitat modification, the main causes of biodiversity loss, these results suggest that ecosystem response to changing biodiversity is likely to be more complex than other studies have shown.
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.
Decomposing Curricular Objectives To Increase Specificity of Instruction.
ERIC Educational Resources Information Center
Marzano, Robert J.
Advances in cognitive science have greatly increased our knowledge of how the human mind stores and uses information. That knowledge can be used to decompose curricular objectives so as to increase the specificity of instruction to a level of precision that should greatly enhance student writing. This article identifies some major types of…
Two-dimensional convolute integers for analytical instrumentation
NASA Technical Reports Server (NTRS)
Edwards, T. R.
1982-01-01
As new analytical instruments and techniques emerge with increased dimensionality, a corresponding need is seen for data processing logic which can appropriately address the data. Two-dimensional measurements reveal enhanced unknown mixture analysis capability as a result of the greater spectral information content over two one-dimensional methods taken separately. It is noted that two-dimensional convolute integers are merely an extension of the work by Savitzky and Golay (1964). It is shown that these low-pass, high-pass and band-pass digital filters are truly two-dimensional and that they can be applied in a manner identical with their one-dimensional counterpart, that is, a weighted nearest-neighbor, moving average with zero phase shifting, convoluted integer (universal number) weighting coefficients.
Spin transitions in graphene butterflies at an integer filling factor
NASA Astrophysics Data System (ADS)
Ghazaryan, Areg; Chakraborty, Tapash
2015-03-01
Recent experiments on the role of electron-electron interactions in fractal Dirac systems have revealed a host of interesting effects, in particular, the unique nature of the magnetic field dependence of butterfly gaps in graphene. The novel gap structure recently observed in the integer quantum Hall effect is quite intriguing [G. L. Yu et al., Nat. Phys. 10, 525 (2014), 10.1038/nphys2979], where one observes a suppression of the ferromagnetic state at one value of the commensurable flux but a reentrant ferromagnetic state at another. In our present work we introduce the magnetic translation symmetry in the integer quantum Hall effect regime and consider the interplay between the electron-electron interaction and the periodic potential. In this approach, we explain the underlying physical processes that can lead to such a unique behavior of the butterfly gaps as observed in that system where we invoke the spin-flip transitions in the ground state.
On the integer coding profile of JPEG XT
NASA Astrophysics Data System (ADS)
Richter, Thomas
2014-09-01
JPEG XT (ISO/IEC 18477), the latest standardization initiative of the JPEG committee defines an image compression standard backwards compatible to the well-known JPEG standard (ISO/IEC 10918-1). JPEG XT extends JPEG by features like coding of images of higher bit-depth, coding of floating point image formats and lossless compression, all of which are backwards compatible to the legacy JPEG standard. In this work, the author presents profiles of JPEG XT that are especially suited for hardware implementations by requiring only integer logic. All functional blocks of a JPEG XT codec are here implemented by integer or fixed point logic. A performance analysis and comparison with other profiles of JPEG XT concludes the work.
Optimization of integer wavelet transforms based on difference correlation structures.
Li, Hongliang; Liu, Guizhong; Zhang, Zhongwei
2005-11-01
In this paper, a novel lifting integer wavelet transform based on difference correlation structure (DCCS-LIWT) is proposed. First, we establish a relationship between the performance of a linear predictor and the difference correlations of an image. The obtained results provide a theoretical foundation for the following construction of the optimal lifting filters. Then, the optimal prediction lifting coefficients in the sense of least-square prediction error are derived. DCCS-LIWT puts heavy emphasis on image inherent dependence. A distinct feature of this method is the use of the variance-normalized autocorrelation function of the difference image to construct a linear predictor and adapt the predictor to varying image sources. The proposed scheme also allows respective calculations of the lifting filters for the horizontal and vertical orientations. Experimental evaluation shows that the proposed method produces better results than the other well-known integer transforms for the lossless image compression.
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.
A fast complex integer convolution using a hybrid transform
NASA Technical Reports Server (NTRS)
Reed, I. S.; K Truong, T.
1978-01-01
It is shown that the Winograd transform can be combined with a complex integer transform over the Galois field GF(q-squared) to yield a new algorithm for computing the discrete cyclic convolution of complex number points. By this means a fast method for accurately computing the cyclic convolution of a sequence of complex numbers for long convolution lengths can be obtained. This new hybrid algorithm requires fewer multiplications than previous algorithms.
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.
Optimal Estimation of a Subset of Integers with Application to GNSS
NASA Astrophysics Data System (ADS)
Brack, A.
2016-12-01
The problem of integer or mixed integer/real valued parameter estimation in linear models is considered. It is a well-known result that for zero-mean additive Gaussian measurement noise the integer least-squares estimator is optimal in the sense of maximizing the probability of correctly estimating the full vector of integer parameters. In applications such as global navigation satellite system ambiguity resolution, it can be beneficial to resolve only a subset of all integer parameters. We derive the estimator that leads to the highest possible success rate for a given integer subset and compare its performance to suboptimal integer mappings via numerical studies. Implementation aspects of the optimal estimator as well as subset selection criteria are discussed.
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.
Catalytic-cartridge SO/sub 3/ decomposer
Galloway, T.R.
1981-05-22
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.
Menu-Driven Solver Of Linear-Programming Problems
NASA Technical Reports Server (NTRS)
Viterna, L. A.; Ferencz, D.
1992-01-01
Program assists inexperienced user in formulating linear-programming problems. A Linear Program Solver (ALPS) computer program is full-featured LP analysis program. Solves plain linear-programming problems as well as more-complicated mixed-integer and pure-integer programs. Also contains efficient technique for solution of purely binary linear-programming problems. Written entirely in IBM's APL2/PC software, Version 1.01. Packed program contains licensed material, property of IBM (copyright 1988, all rights reserved).
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.
Simultaneous CDMA and error correction schemes based on wavelet filters in integer quotient rings
NASA Astrophysics Data System (ADS)
Lay, Kuen-Tsair; Kong, Lin-Wen; Chen, Jiann-Horng
2000-04-01
In the past decade, wavelet filters have been widely applied to signal processing. In effect, wavelet filters are perfect reconstruction filter banks (PRFBs). However, in most researches, the filterbanks and wavelets operate on real- valued or complex-valued signals. In this paper, PRFBs operating over integer quotient rings (IQRs) are introduced. We denote an IQR as Z/(q). Algorithms for constructing such filter banks are proposed. The PRFB design can be carried out either in the time or the frequency domain. We demonstrate that some classical or well known filter tap coefficients can even be transformed into values over Z/(q) in a simple and straightforward way. Here we emphasize that to achieve perfect reconstruction (PR), the filters need not to work on elements in fields. In fact, operating on elements in IQRs can achieve PR with proper choices of a ring and filter tap coefficients. The designed filter banks can be orthogonal or biorthogonal. Based ona PRFB over an IQR, to which we refer as an IQR-PRFB, a perfect reconstruction transmultiplexer (PRTM), to which we refer as an IQR-PRTM, can be derived. Through the utilization of the IQR-PRTM multiplexing and multiple access in a multi-user digital communication system can be realized. The IQR-PRTM effectively decomposes the communication signal space into several orthogonal subspaces, where each multiplexed user sends his message in one of them. If some of the orthogonal subspaces are preserved for parity check, then error correction at the receiving end can be performed. In the proposed schemes, the data to be transmitted must be represented with elements of Z/(q), which can be done easily. A modulation and demodulation/detection scheme, in conjunction with the IQR-PRTM is proposed.
Quantum field theory in non-integer dimensions
Eyink, G.L.
1987-01-01
In a 1973 paper entitled Quantum Field-Theory Models in Less Than 4 Dimensions, Kenneth G. Wilson studied field-theories for spacetime dimension d between 2 and 4. With unconventional renormalizations, these models were found to have non-Gaussian ultraviolet renormalization group fixed points. Wilson's method was perturbative dimensional regularization: the Feynman-graph integrals were analytically continued to non-integer d. His work left open the question of the nonperturbative existence of the models. Since that landmark paper, Yuval Gefen, Amnon Aharony and Benoit B. Mandelbrot have shown that Ising spin models on fractal lattices have critical properties like those predicted for non-integer dimensions by the analytic continuation, or {epsilon}-expansion method. This work shows that fractal lattices and continua provide also a nonperturbative definition of field-theories in non-integer dimensions. The fractal point-sets employed are the Sierpinski carpets and their higher-dimensional generalizations. This class of point-sets has a tunable dimension which allows the approach to four from below. Furthermore, the carpets have discrete groups of scale or dilation invariances and infinite order of ramification. A class of scalar field models are defined on these sets which should reduce to the standard models when d {nearrow}4. The propagator for these models is given by a proper-time or heat-kernel representation. For this propagator, reflection-positivity is established, a general scaling law is conjectured (and established in a special case), and the perturbative renormalizability shown to be governed by the spectral dimensionality. Scalar models with another choice of propagator, the hierarchical propagator, are studied by rigorous renormalization-group methods.
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).
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
The mental representation of numerical fractions: real or integer?
Bonato, Mario; Fabbri, Sara; Umiltà, Carlo; Zorzi, Marco
2007-12-01
Numerical fractions are commonly used to express ratios and proportions (i.e., real numbers), but little is known about how they are mentally represented and processed by skilled adults. Four experiments employed comparison tasks to investigate the distance effect and the effect of the spatial numerical association of response codes (SNARC) for fractions. Results showed that fractions were processed componentially and that the real numerical value of the fraction was not accessed, indicating that processing the fraction's magnitude is not automatic. In contrast, responses were influenced by the numerical magnitude of the components and reflected the simple comparison between numerators, denominators, and reference, depending on the strategy adopted. Strategies were used even by highly skilled participants and were flexibly adapted to the specific experimental context. In line with results on the whole number bias in children, these findings suggest that the understanding of fractions is rooted in the ability to represent discrete numerosities (i.e., integers) rather than real numbers and that the well-known difficulties of children in mastering fractions are circumvented by skilled adults through a flexible use of strategies based on the integer components.
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.
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
Soft Decoding of Integer Codes and Their Application to Coded Modulation
NASA Astrophysics Data System (ADS)
Kostadinov, Hristo; Morita, Hiroyoshi; Iijima, Noboru; Han Vinck, A. J.; Manev, Nikolai
Integer codes are very flexible and can be applied in different modulation schemes. A soft decoding algorithm for integer codes will be introduced. Comparison of symbol error probability (SEP) versus signal-to-noise ratio (SNR) between soft and hard decoding using integer coded modulation shows us that we can obtain at least 2dB coding gain. Also, we shall compare our results with trellis coded modulation (TCM) because of their similar decoding schemes and complexity.
Simple Thermal Decompose Method for Synthesis of Nickel Disulfide Nanostructures
NASA Astrophysics Data System (ADS)
Seyghalkar, Hamideh; Sabet, Mohammad; Salavati-Niasari, Masoud
2016-11-01
In this work, a simple thermal decompose method was served to synthesize NiS2 nanostructures via a nickel complex. Also polyethylene glycol (PEG) was used as surfactant to increase the steric effect around nanostructure surfaces and decrease the particles size. The product was characterized with different analysis methods. The crystal structure of the product was studied by X-ray diffraction (XRD) pattern. The particle size and morphology were investigated by scanning electron microscopy (SEM). To study the nanostructures surface purity, Fourier transform infrared spectroscopy (FT-IR) was used. And finally to study the optical properties of the product photoluminescence (PL) spectroscopy was served.
An alternative approach to calculate the posterior probability of GNSS integer ambiguity resolution
NASA Astrophysics Data System (ADS)
Yu, Xianwen; Wang, Jinling; Gao, Wang
2017-03-01
When precise positioning is carried out via GNSS carrier phases, it is important to make use of the property that every ambiguity should be an integer. With the known float solution, any integer vector, which has the same degree of freedom as the ambiguity vector, is the ambiguity vector in probability. For both integer aperture estimation and integer equivariant estimation, it is of great significance to know the posterior probabilities. However, to calculate the posterior probability, we have to face the thorny problem that the equation involves an infinite number of integer vectors. In this paper, using the float solution of ambiguity and its variance matrix, a new approach to rapidly and accurately calculate the posterior probability is proposed. The proposed approach consists of four steps. First, the ambiguity vector is transformed via decorrelation. Second, the range of the adopted integer of every component is directly obtained via formulas, and a finite number of integer vectors are obtained via combination. Third, using the integer vectors, the principal value of posterior probability and the correction factor are worked out. Finally, the posterior probability of every integer vector and its error upper bound can be obtained. In the paper, the detailed process to calculate the posterior probability and the derivations of the formulas are presented. The theory and numerical examples indicate that the proposed approach has the advantages of small amount of computations, high calculation accuracy and strong adaptability.
An alternative approach to calculate the posterior probability of GNSS integer ambiguity resolution
NASA Astrophysics Data System (ADS)
Yu, Xianwen; Wang, Jinling; Gao, Wang
2016-10-01
When precise positioning is carried out via GNSS carrier phases, it is important to make use of the property that every ambiguity should be an integer. With the known float solution, any integer vector, which has the same degree of freedom as the ambiguity vector, is the ambiguity vector in probability. For both integer aperture estimation and integer equivariant estimation, it is of great significance to know the posterior probabilities. However, to calculate the posterior probability, we have to face the thorny problem that the equation involves an infinite number of integer vectors. In this paper, using the float solution of ambiguity and its variance matrix, a new approach to rapidly and accurately calculate the posterior probability is proposed. The proposed approach consists of four steps. First, the ambiguity vector is transformed via decorrelation. Second, the range of the adopted integer of every component is directly obtained via formulas, and a finite number of integer vectors are obtained via combination. Third, using the integer vectors, the principal value of posterior probability and the correction factor are worked out. Finally, the posterior probability of every integer vector and its error upper bound can be obtained. In the paper, the detailed process to calculate the posterior probability and the derivations of the formulas are presented. The theory and numerical examples indicate that the proposed approach has the advantages of small amount of computations, high calculation accuracy and strong adaptability.
VARIANCE ESTIMATION IN DOMAIN DECOMPOSED MONTE CARLO EIGENVALUE CALCULATIONS
Mervin, Brenden T; Maldonado, G. Ivan; Mosher, Scott W; Evans, Thomas M; Wagner, John C
2012-01-01
The number of tallies performed in a given Monte Carlo calculation is limited in most modern Monte Carlo codes by the amount of memory that can be allocated on a single processor. By using domain decomposition, the calculation is now limited by the total amount of memory available on all processors, allowing for significantly more tallies to be performed. However, decomposing the problem geometry introduces significant issues with the way tally statistics are conventionally calculated. In order to deal with the issue of calculating tally variances in domain decomposed environments for the Shift hybrid Monte Carlo code, this paper presents an alternative approach for reactor scenarios in which an assumption is made that once a particle leaves a domain, it does not reenter the domain. Particles that reenter the domain are instead treated as separate independent histories. This assumption introduces a bias that inevitably leads to under-prediction of the calculated variances for tallies within a few mean free paths of the domain boundaries. However, through the use of different decomposition strategies, primarily overlapping domains, the negative effects of such an assumption can be significantly reduced to within reasonable levels.
Multistate image restoration by transmission of bit-decomposed data.
Tadaki, Takashi; Inoue, Jun-ichi
2002-01-01
We report on the restoration of gray-scale image when it is decomposed into a binary form before transmission. We assume that a gray-scale image expressed by a set of Q-Ising spins is first decomposed into an expression using Ising (binary) spins by means of the threshold division, namely, we produce (Q-1) binary Ising spins from a Q-Ising spin by the function F(sigma(i)-m)=1 if the input data sigma(i)in[0,...,Q-1] is sigma(i)> or =m and 0 otherwise, where m in [1,...,Q-1] is the threshold value. The effects of noise are different from the case where the raw Q-Ising values are sent. We investigate whether it is more effective to use the binary data for transmission, or to send the raw Q-Ising values. By using the mean-field model, we analyze the performance of our method quantitatively. In order to investigate what kind of original picture is efficiently restored by our method, the standard image in two dimensions is simulated by the mean-field annealing, and we compare the performance of our method with that using the Q-Ising form. We show that our method is more efficient than the one using the Q-Ising form when the original picture has large parts in which the nearest-neighboring pixels take close values.
Functional diversity of terrestrial microbial decomposers and their substrates.
Hättenschwiler, Stephan; Fromin, Nathalie; Barantal, Sandra
2011-05-01
The relationship between biodiversity and biogeochemical processes gained much interest in light of the rapidly decreasing biodiversity worldwide. In this article, we discuss the current status, challenges and prospects of functional concepts to plant litter diversity and microbial decomposer diversity. We also evaluate whether these concepts permit a better understanding of how biodiversity is linked to litter decomposition as a key ecosystem process influencing carbon and nutrient cycles. Based on a literature survey, we show that plant litter and microbial diversity matters for decomposition, but that considering numbers of taxonomic units appears overall as little relevant and less useful than functional diversity. However, despite easily available functional litter traits and the well-established theoretical framework for functional litter diversity, the impact of functional litter diversity on decomposition is not yet well enough explored. Defining functional diversity of microorganisms remains one of the biggest challenges for functional approaches to microbial diversity. Recent developments in microarray and metagenomics technology offer promising possibilities in the assessment of the functional structure of microbial communities. This might allow significant progress in measuring functional microbial diversity and ultimately in our ability to predict consequences of biodiversity loss in the decomposer system for biogeochemical processes.
Transcranial Magnetic Stimulation: Decomposing the Processes Underlying Action Preparation.
Bestmann, Sven; Duque, Julie
2016-08-01
Preparing actions requires the operation of several cognitive control processes that influence the state of the motor system to ensure that the appropriate behavior is ultimately selected and executed. For example, some form of competition resolution ensures that the right action is chosen among alternatives, often in the presence of conflict; at the same time, impulse control ought to be deployed to prevent premature responses. Here we review how state-changes in the human motor system during action preparation can be studied through motor-evoked potentials (MEPs) elicited by transcranial magnetic stimulation over the contralateral primary motor cortex (M1). We discuss how the physiological fingerprints afforded by MEPs have helped to decompose some of the dynamic and effector-specific influences on the motor system during action preparation. We focus on competition resolution, conflict and impulse control, as well as on the influence of higher cognitive decision-related variables. The selected examples demonstrate the usefulness of MEPs as physiological readouts for decomposing the influence of distinct, but often overlapping, control processes on the human motor system during action preparation.
Decomposing the meridional heat transport in the climate system
NASA Astrophysics Data System (ADS)
Yang, Haijun; Li, Qing; Wang, Kun; Sun, Yu; Sun, Daoxun
2015-05-01
The meridional heat transport (MHT) in the climate system is investigated using a state-of-the-art coupled climate model (CESM1.0). This work decomposes the MHT and studies their physics in detail. The meridional ocean heat transport (OHT) can be decomposed into the contributions from the Euler mean circulation, bolus circulation, sub-mesoscale circulation and dissipation. The Euler mean heat transport dominates the total OHT in most latitudes, except that in the Southern Ocean (40-50°S) where the OHT is determined by the eddy-induced circulation and dissipation. In the Indo-Pacific the OHT is fulfilled by the wind-driven circulation, which dominates the total global OHT in the tropics. In the Atlantic the OHT is carried by both the wind-driven circulation and the thermohaline circulation, and the latter dominates the total OHT in the mid-high latitudes. The meridional atmosphere heat transport consists of the dry static energy (DSE) and latent energy (LE) transport. In the tropics the LE transport is equatorward and compensates partially the poleward DSE transport. In the extratropics, the LE and DSE are poleward and reinforce one another, both of which are dominated by the eddy components. The LE transport can be considered as the "joint air-sea mode" since the ocean controls the moisture supply. It can be also precisely obtained from the evaporation minus precipitation over the ocean and thus this work quantifies the individual ocean basin contributions to the LE transport.
Parallel integer sorting with medium and fine-scale parallelism
NASA Technical Reports Server (NTRS)
Dagum, Leonardo
1993-01-01
Two new parallel integer sorting algorithms, queue-sort and barrel-sort, are presented and analyzed in detail. These algorithms do not have optimal parallel complexity, yet they show very good performance in practice. Queue-sort designed for fine-scale parallel architectures which allow the queueing of multiple messages to the same destination. Barrel-sort is designed for medium-scale parallel architectures with a high message passing overhead. The performance results from the implementation of queue-sort on a Connection Machine CM-2 and barrel-sort on a 128 processor iPSC/860 are given. The two implementations are found to be comparable in performance but not as good as a fully vectorized bucket sort on the Cray YMP.
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.
Three-dimensional image compression with integer wavelet transforms.
Bilgin, A; Zweig, G; Marcellin, M W
2000-04-10
A three-dimensional (3-D) image-compression algorithm based on integer wavelet transforms and zerotree coding is presented. The embedded coding of zerotrees of wavelet coefficients (EZW) algorithm is extended to three dimensions, and context-based adaptive arithmetic coding is used to improve its performance. The resultant algorithm, 3-D CB-EZW, efficiently encodes 3-D image data by the exploitation of the dependencies in all dimensions, while enabling lossy and lossless decompression from the same bit stream. Compared with the best available two-dimensional lossless compression techniques, the 3-D CB-EZW algorithm produced averages of 22%, 25%, and 20% decreases in compressed file sizes for computed tomography, magnetic resonance, and Airborne Visible Infrared Imaging Spectrometer images, respectively. The progressive performance of the algorithm is also compared with other lossy progressive-coding algorithms.
Three-Dimensional Image Compression With Integer Wavelet Transforms
NASA Astrophysics Data System (ADS)
Bilgin, Ali; Zweig, George; Marcellin, Michael W.
2000-04-01
A three-dimensional (3-D) image-compression algorithm based on integer wavelet transforms and zerotree coding is presented. The embedded coding of zerotrees of wavelet coefficients (EZW) algorithm is extended to three dimensions, and context-based adaptive arithmetic coding is used to improve its performance. The resultant algorithm, 3-D CB-EZW, efficiently encodes 3-D image data by the exploitation of the dependencies in all dimensions, while enabling lossy and lossless decompression from the same bit stream. Compared with the best available two-dimensional lossless compression techniques, the 3-D CB-EZW algorithm produced averages of 22%, 25%, and 20% decreases in compressed file sizes for computed tomography, magnetic resonance, and Airborne Visible Infrared Imaging Spectrometer images, respectively. The progressive performance of the algorithm is also compared with other lossy progressive-coding algorithms.
Integer quantum Hall effect of interacting electrons in graphene
NASA Astrophysics Data System (ADS)
Yan, Xin-Zhong; Ting, C. S.
2017-02-01
By taking into account the charge and spin orderings and the exchange interactions between all the Landau levels, we investigate the integer quantum Hall effect of electrons in graphene using the mean-field theory. We find that the fourfold degeneracy of the Landau levels cannot be completely lifted by the Coulomb interactions. In particular, at fillings ν =4 n +2 with n =0 ,1 ,... , there is no splitting between the fourfold degenerated Landau levels. We show that with doping the degenerated lowest empty level can be sequentially filled one by one; the filled level is lower than the empty ones because of the Coulomb-exchange interactions. This result explains the step Δ ν =1 in the quantized Hall conductivity. We present a highly efficient method for dealing with a huge number of the Coulomb couplings between all the Landau levels of the Dirac fermions.
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.
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.
Integral-valued polynomials over sets of algebraic integers of bounded degree.
Peruginelli, Giulio
2014-04-01
Let K be a number field of degree n with ring of integers [Formula: see text]. By means of a criterion of Gilmer for polynomially dense subsets of the ring of integers of a number field, we show that, if [Formula: see text] maps every element of [Formula: see text] of degree n to an algebraic integer, then [Formula: see text] is integral-valued over [Formula: see text], that is, [Formula: see text]. A similar property holds if we consider the set of all algebraic integers of degree n and a polynomial [Formula: see text]: if [Formula: see text] is integral over [Formula: see text] for every algebraic integer α of degree n, then [Formula: see text] is integral over [Formula: see text] for every algebraic integer β of degree smaller than n. This second result is established by proving that the integral closure of the ring of polynomials in [Formula: see text] which are integer-valued over the set of matrices [Formula: see text] is equal to the ring of integral-valued polynomials over the set of algebraic integers of degree equal to n.
Mining functional modules in genetic networks with decomposable graphical models.
Dejori, Mathäus; Schwaighofer, Anton; Tresp, Volker; Stetter, Martin
2004-01-01
In recent years, graphical models have become an increasingly important tool for the structural analysis of genome-wide expression profiles at the systems level. Here we present a new graphical modelling technique, which is based on decomposable graphical models, and apply it to a set of gene expression profiles from acute lymphoblastic leukemia (ALL). The new method explains probabilistic dependencies of expression levels in terms of the concerted action of underlying genetic functional modules, which are represented as so-called "cliques" in the graph. In addition, the method uses continuous-valued (instead of discretized) expression levels, and makes no particular assumption about their probability distribution. We show that the method successfully groups members of known functional modules to cliques. Our method allows the evaluation of the importance of genes for global cellular functions based on both link count and the clique membership count.
Upgrading non-oxidized carbon nanotubes by thermally decomposed hydrazine
NASA Astrophysics Data System (ADS)
Wang, Pen-Cheng; Liao, Yu-Chun; Liu, Li-Hung; Lai, Yu-Ling; Lin, Ying-Chang; Hsu, Yao-Jane
2014-06-01
We found that the electrical properties of conductive thin films based on non-oxidized carbon nanotubes (CNTs) could be further improved when the CNTs consecutively underwent a mild hydrazine adsorption treatment and then a sufficiently effective thermal desorption treatment. We also found that, after several rounds of vapor-phase hydrazine treatments and baking treatments were applied to an inferior single-CNT field-effect transistor device, the device showed improvement in Ion/Ioff ratio and reduction in the extent of gate-sweeping hysteresis. Our experimental results indicate that, even though hydrazine is a well-known reducing agent, the characteristics of our hydrazine-exposed CNT samples subject to certain treatment conditions could become more graphenic than graphanic, suggesting that the improvement in the electrical and electronic properties of CNT samples could be related to the transient bonding and chemical scavenging of thermally decomposed hydrazine on the surface of CNTs.
Decomposing Spatiotemporal Brain Patterns into Topographic Latent Sources
Gershman, Samuel J.; Blei, David M.; Norman, Kenneth A.; Sederberg, Per B.
2014-01-01
This paper extends earlier work on spatial modeling of fMRI data to the temporal domain, providing a framework for analyzing high temporal resolution brain imaging modalities such as electroencapholography (EEG). The central idea is to decompose brain imaging data into a covariate-dependent superposition of functions defined over continuous time and space (what we refer to as topographic latent sources). The continuous formulation allows us to parametrically model spatiotemporally localized activations. To make group-level inferences, we elaborate the model hierarchically by sharing sources across subjects. We describe a variational algorithm for parameter estimation that scales efficiently to large data sets. Applied to three EEG data sets, we find that the model produces good predictive performance and reproduces a number of classic findings. Our results suggest that topographic latent sources serve as an effective hypothesis space for interpreting spatiotemporal brain imaging data. PMID:24791745
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
2+1 flavor lattice QCD with Luscher's Domain-Decomposed HMC algorithm
NASA Astrophysics Data System (ADS)
Kuramashi, Yoshinobu
2006-12-01
We report on a study of 2+1 flavor lattice QCD with the O(a)-improved Wilson quarks on a 163 × 32 lattice at the lattice spacing 1/a ≈ 2GeV employing Lüscher's domain-decomposed HMC(LDDHMC) algorithm. This is dedicated to a preliminary study for the PACS-CS project which plans to complete the Wilson-clover N f = 2 + 1 program lowering the up-down quark masses close to the physical values as much as possible. We focus on three issues: (i) how light quark masses we can reach with LDDHMC, (ii) efficiency of the algorithm compared with the conventional HMC, (iii) parameter choice for the production runs on PACS-CS.
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
Edge states and integer quantum Hall effect in topological insulator thin films
NASA Astrophysics Data System (ADS)
Zhang, Song-Bo; Lu, Hai-Zhou; Shen, Shun-Qing
The integer quantum Hall effect is a topological state of quantum matter in two dimensions, and has recently been observed in three-dimensional topological insulator thin films. In this report, I will talk about the Landau levels and edge states of surface Dirac fermions in topological insulators under a strong magnetic field. We examine the formation of the quantum plateaux of the Hall conductance and find two different patterns, in one pattern the filling number covers all integers while only odd integers in the other. We focus on the quantum plateau closest to zero energy and demonstrate the breakdown of the quantum spin Hall effect as a result of the interplay of magnetic field and structure inversion asymmetry. We also reveal that the edge states exist only for the integer Hall conductance while no edge-state solution can be found for the ''half-integer'' Hall conductance. The addition of top and bottom surface Dirac fermions always form well-defined edge states, and gives an integer quantum Hall effect. This work establishes an intuitive picture of the edge states to understand the integer quantum Hall effect for Dirac electrons in topological insulator thin films.
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.
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.
The transport mechanism of the integer quantum Hall effect
NASA Astrophysics Data System (ADS)
Hui, Tan; LiMing, W.; Liang, Shi-Dong
2016-11-01
The integer quantum Hall effect (IQHE) is analysed using a mechanism of the electron transport in the form of semi-classic wave packages in this paper. Due to the confinement of the edges of a slab the Landau levels of electrons in a strong magnetic field go up at large wave-vectors to form energy bands. The slopes of the energy bands give the group velocities of electron wave packages and thus contribute to the current. Certain magnetic fields separate the electron transport in the slab into two branches with opposite and large wave vectors, which are localized at the two edges of the slab, respectively. In this case back scattering of electrons is prohibited due to the localization of these two branches. Thus the slab exhibits zero longitudinal resistance and plateaus of Hall resistance. When the Fermi level is sweeping over a Landau level at some magnetic fields, however, the electron waves locate around the central axis of the slab and overlap each other thus back scattering of electrons takes place frequently. Then longitudinal resistance appears and the Hall resistance goes up from one plateau to a new one. This transport mechanism is much clearer and more intuitive than the conventional explanations to the IQHE.
Forward scattering approximation and bosonization in integer quantum Hall systems
Rosenau da Costa, M. Westfahl, H.; Caldeira, A.O.
2008-03-15
In this work, we present a model and a method to study integer quantum Hall (IQH) systems. Making use of the Landau levels structure we divide these two-dimensional systems into a set of interacting one-dimensional gases, one for each guiding center. We show that the so-called strong field approximation, used by Kallin and Halperin and by MacDonald, is equivalent, in first order, to a forward scattering approximation and analyze the IQH systems within this approximation. Using an appropriate variation of the Landau level bosonization method we obtain the dispersion relations for the collective excitations and the single-particle spectral functions. For the bulk states, these results evidence a behavior typical of non-normal strongly correlated systems, including the spin-charge splitting of the single-particle spectral function. We discuss the origin of this behavior in the light of the Tomonaga-Luttinger model and the bosonization of two-dimensional electron gases.
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.
Module detection in complex networks using integer optimisation
2010-01-01
Background The detection of modules or community structure is widely used to reveal the underlying properties of complex networks in biology, as well as physical and social sciences. Since the adoption of modularity as a measure of network topological properties, several methodologies for the discovery of community structure based on modularity maximisation have been developed. However, satisfactory partitions of large graphs with modest computational resources are particularly challenging due to the NP-hard nature of the related optimisation problem. Furthermore, it has been suggested that optimising the modularity metric can reach a resolution limit whereby the algorithm fails to detect smaller communities than a specific size in large networks. Results We present a novel solution approach to identify community structure in large complex networks and address resolution limitations in module detection. The proposed algorithm employs modularity to express network community structure and it is based on mixed integer optimisation models. The solution procedure is extended through an iterative procedure to diminish effects that tend to agglomerate smaller modules (resolution limitations). Conclusions A comprehensive comparative analysis of methodologies for module detection based on modularity maximisation shows that our approach outperforms previously reported methods. Furthermore, in contrast to previous reports, we propose a strategy to handle resolution limitations in modularity maximisation. Overall, we illustrate ways to improve existing methodologies for community structure identification so as to increase its efficiency and applicability. PMID:21073720
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.
Integer wavelet transform for embedded lossy to lossless image compression.
Reichel, J; Menegaz, G; Nadenau, M J; Kunt, M
2001-01-01
The use of the discrete wavelet transform (DWT) for embedded lossy image compression is now well established. One of the possible implementations of the DWT is the lifting scheme (LS). Because perfect reconstruction is granted by the structure of the LS, nonlinear transforms can be used, allowing efficient lossless compression as well. The integer wavelet transform (IWT) is one of them. This is an interesting alternative to the DWT because its rate-distortion performance is similar and the differences can be predicted. This topic is investigated in a theoretical framework. A model of the degradations caused by the use of the IWT instead of the DWT for lossy compression is presented. The rounding operations are modeled as additive noise. The noise are then propagated through the LS structure to measure their impact on the reconstructed pixels. This methodology is verified using simulations with random noise as input. It predicts accurately the results obtained using images compressed by the well-known EZW algorithm. Experiment are also performed to measure the difference in terms of bit rate and visual quality. This allows to a better understanding of the impact of the IWT when applied to lossy image compression.
The dip effect under integer quantized Hall conditions
NASA Astrophysics Data System (ADS)
Gulebaglan, Sinem Erden; Kalkan, Sirri Batuhan; Sirt, Serkan; Kendirlik, Enver Metin; Siddiki, Afif
2014-03-01
In this work we investigate an unusual transport phenomenon observed in two-dimensional electron gas under integer quantum Hall effect conditions. Our calculations are based on the screening theory, using a semi-analytical model. The transport anomalies are dip and overshoot effects, where the Hall resistance decreases (or increases) unexpectedly at the quantized resistance plateaus intervals. We report on our numerical findings of the dip effect in the Hall resistance, considering GaAs/AlGaAs heterostructures in which we investigated the effect under different experimental conditions. We show that, similar to overshoot, the amplitude of the dip effect is strongly influenced by the edge reconstruction due to electrostatics. It is observed that the steep potential variation close to the physical boundaries of the sample results in narrower incompressible strips, hence, the experimental observation of the dip effect is limited by the properties of these current carrying strips. By performing standard Hall resistance measurements on gate defined narrow samples, we demonstrate that the predictions of the screening theory is in well agreement with our experimental findings.
Tumebacillus algifaecis sp. nov., isolated from decomposing algal scum.
Wu, Yu-Fan; Zhang, Bo; Xing, Peng; Wu, Qing-Long; Liu, Shuang-Jiang
2015-07-01
Bacterial strain THMBR28(T) was isolated from decomposing algal scum that was collected during an algal bloom in Taihu lake, China. Cells of strain THMBR28(T) were Gram-staining-positive, facultatively anaerobic and rod-shaped. Growth was observed at 20-45 °C (optimum, 30 °C), at pH 5.0-9.5 (optimum, pH 6.5-7.5), and in the presence of 0-1.0% (w/v) NaCl (optimum, 0.5%). Strain THMBR28(T) contained MK-7 as the major menaquinone and iso-C15 : 0 as the major cellular fatty acid. The polar lipid profile contained phosphatidylglycerol, phosphatidylmonomethylethanolamine, phosphatidylethanolamine and six unidentified polar lipids. The diamino acid found in the cell-wall peptidoglycan was meso-diaminopimelic acid. The DNA G+C content was 57.6 mol% (Tm). Phylogenetic analysis of 16S rRNA gene sequences showed that strain THMBR28(T) belonged to the genus Tumebacillus, most closely related to Tumebacillus ginsengisoli DSM 18389(T) (95.0%) and Tumebacillus permanentifrigoris Eur1 9.5(T) (93.4%). Based on phylogenetic and phenotypic characterization, it is concluded that strain THMBR28(T) represents a novel species of the genus Tumebacillus, for which the name Tumebacillus algifaecis sp. nov. is proposed, with THMBR28(T) ( = CGMCC 1.10949(T) = NBRC 108765(T)) as the type strain.
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.
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.
Degradation of chlorinated pesticide DDT by litter-decomposing basidiomycetes.
Suhara, Hiroto; Adachi, Ai; Kamei, Ichiro; Maekawa, Nitaro
2011-11-01
One hundred and two basidiomycete strains (93 species in 41 genera) that prefer a soil environment were examined for screening of 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (DDT) biodegradation. Three strains within two litter-decomposing genera, Agrocybe and Marasmiellus, were selected for their DDT biotransformation capacity. Eight metabolites; 1,1-dichloro-2,2-bis(4-chlorophenyl)ethane (DDD), two monohydroxy-DDTs, monohydroxy-DDD, 2,2-dichloro-1,1-bis(4-chlorophenyl)ethanol, putative 2,2-bis(4-chlorophenyl)ethanol and two unidentified compounds were detected from the culture with Marasmiellus sp. TUFC10101. A P450 inhibitor, 1-ABT, inhibited the formation of monohydroxy-DDTs and monohydroxy-DDD from DDT and DDD, respectively. These results indicated that oxidative pathway which was catalyzed by P450 monooxygenase exist beside reductive dechlorination of DDT. Monohydroxylation of the aromatic rings of DDT (and DDD) by fungal P450 is reported here for the first time.
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.
Temperature effect on photolysis decomposing of perfluorooctanoic acid.
Zhang, Tiliang; Pan, Gang; Zhou, Qin
2016-04-01
Perfluorooctanoic acid (PFOA) is recalcitrant to degrade and mineralize. Here, the effect of temperature on the photolytic decomposition of PFOA was investigated. The decomposition of PFOA was enhanced from 34% to 99% in 60 min of exposure when the temperature was increased from 25 to 85°C under UV light (201-600 nm). The limited degree of decomposition at 25°C was due to low quantum yield, which was increased by a factor of 12 at 85°C. Under the imposed conditions, the defluorination ratio increased from 8% at 25°C to 50% at 85°C in 60 min. Production of perfluorinated carboxylic acids (PFCAs, C7-C5), PFCAs (C4-C3) and TFA (trifluoroacetic acid, C2) accelerated and attained a maximum within 30 to 90 min at 85°C. However, these reactions did not occur at 25°C despite extended irradiation to 180 min. PFOA was decomposed in a step-wise process by surrendering one CF2 unit. In each cyclical process, increased temperature enhanced the quantum yields of irradiation and reactions between water molecules and intermediates radicals. The energy consumption for removing each μmol of PFOA was reduced from 82.5 kJ at 25°C to 10.9 kJ at 85°C using photolysis. Photolysis coupled with heat achieved high rates of PFOA degradation and defluorination.
Decomposing the aerodynamic forces of low-Reynolds flapping airfoils
NASA Astrophysics Data System (ADS)
Moriche, Manuel; Garcia-Villalba, Manuel; Flores, Oscar
2016-11-01
We present direct numerical simulations of flow around flapping NACA0012 airfoils at relatively small Reynolds numbers, Re = 1000 . The simulations are carried out with TUCAN, an in-house code that solves the Navier-Stokes equations for an incompressible flow with an immersed boundary method to model the presence of the airfoil. The motion of the airfoil is composed of a vertical translation, heaving, and a rotation about the quarter of the chord, pitching. Both motions are prescribed by sinusoidal laws, with a reduced frequency of k = 1 . 41 , a pitching amplitude of 30deg and a heaving amplitude of one chord. Both, the mean pitch angle and the phase shift between pitching and heaving motions are varied, to build a database with 18 configurations. Four of these cases are analysed in detail using the force decomposition algorithm of Chang (1992) and Martín Alcántara et al. (2015). This method decomposes the total aerodynamic force into added-mass (translation and rotation of the airfoil), a volumetric contribution from the vorticity (circulatory effects) and a surface contribution proportional to viscosity. In particular we will focus on the second, analysing the contribution of the leading and trailing edge vortices that typically appear in these flows. This work has been supported by the Spanish MINECO under Grant TRA2013-41103-P. The authors thankfully acknowledge the computer resources provided by the Red Española de Supercomputacion.
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.
Decomposing ability of filamentous fungi on litter is involved in a subtropical mixed forest.
Song, Fuqiang; Tian, Xingjun; Fan, Xiaoxu; He, Xingbing
2010-01-01
The abilities of 10 filamentous fungi, isolated from Pinus massoniana-Liquidambar formasana mixed forest (PLF), to decompose fresh, fallen needle and leaf litter were studied with pure-culture tests. The results showed that all fungi except Mucor sp. and Chaetomium bostrychodes could drive mass loss of L. formasana leaf litter significantly more than that of P. massoniasa. Mass loss of litter in the first 5 wk of the study was higher than that in the last 5 wk. The decomposition rate was negatively correlated to the original lignin/nitrogen (L/N) and carbohydrate/nitrogen (C/N) ratios. Based on the mass loss of litter (W), carbohydrate (C) and lignin (L), and the mutual relationship between L/W and L/C ratio, we concluded that Mucor sp. had the lowest decomposing ability on P. Massoniana and L. formasana litter and that it could not use lignin. The Chaetomium bostrychodes were lignin and carbohydrate decomposers but preferred lignin. Trichoderma sp. 1 and Cladosporium herbarum were carbohydrate-decomposing fungi. Trichoderma sp. 2, Aspergillus fumigatus, Alternaria sp. and Penicillium sp. 2 were able to decompose lignin and carbohydrate but preferred carbohydrate and had high ability to decompose litter. Aspergillus niger and Penicillium sp. 1 were able to decompose lignin and carbohydrate only in the early phase of the study. The decomposing ability of fungi varied even within genus. No direct relationship was found between the frequency of isolation and the decomposing ability of fungi.
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).
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.
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.
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.
Invertible update-then-predict integer lifting wavelet for lossless image compression
NASA Astrophysics Data System (ADS)
Chen, Dong; Li, Yanjuan; Zhang, Haiying; Gao, Wenpeng
2017-01-01
This paper presents a new wavelet family for lossless image compression by re-factoring the channel representation of the update-then-predict lifting wavelet, introduced by Claypoole, Davis, Sweldens and Baraniuk, into lifting steps. We name the new wavelet family as invertible update-then-predict integer lifting wavelets (IUPILWs for short). To build IUPILWs, we investigate some central issues such as normalization, invertibility, integer structure, and scaling lifting. The channel representation of the previous update-then-predict lifting wavelet with normalization is given and the invertibility is discussed firstly. To guarantee the invertibility, we re-factor the channel representation into lifting steps. Then the integer structure and scaling lifting of the invertible update-then-predict wavelet are given and the IUPILWs are built. Experiments show that comparing with the integer lifting structure of 5/3 wavelet, 9/7 wavelet, and iDTT, IUPILW results in the lower bit-rates for lossless image compression.
Edge states and integer quantum Hall effect in topological insulator thin films.
Zhang, Song-Bo; Lu, Hai-Zhou; Shen, Shun-Qing
2015-08-25
The integer quantum Hall effect is a topological state of quantum matter in two dimensions, and has recently been observed in three-dimensional topological insulator thin films. Here we study the Landau levels and edge states of surface Dirac fermions in topological insulators under strong magnetic field. We examine the formation of the quantum plateaux of the Hall conductance and find two different patterns, in one pattern the filling number covers all integers while only odd integers in the other. We focus on the quantum plateau closest to zero energy and demonstrate the breakdown of the quantum spin Hall effect resulting from structure inversion asymmetry. The phase diagrams of the quantum Hall states are presented as functions of magnetic field, gate voltage and chemical potential. This work establishes an intuitive picture of the edge states to understand the integer quantum Hall effect for Dirac electrons in topological insulator thin films.
Designing cost-effective biopharmaceutical facilities using mixed-integer optimization.
Liu, Songsong; Simaria, Ana S; Farid, Suzanne S; Papageorgiou, Lazaros G
2013-01-01
Chromatography operations are identified as critical steps in a monoclonal antibody (mAb) purification process and can represent a significant proportion of the purification material costs. This becomes even more critical with increasing product titers that result in higher mass loads onto chromatography columns, potentially causing capacity bottlenecks. In this work, a mixed-integer nonlinear programming (MINLP) model was created and applied to an industrially relevant case study to optimize the design of a facility by determining the most cost-effective chromatography equipment sizing strategies for the production of mAbs. Furthermore, the model was extended to evaluate the ability of a fixed facility to cope with higher product titers up to 15 g/L. Examination of the characteristics of the optimal chromatography sizing strategies across different titer values enabled the identification of the maximum titer that the facility could handle using a sequence of single column chromatography steps as well as multi-column steps. The critical titer levels for different ratios of upstream to dowstream trains where multiple parallel columns per step resulted in the removal of facility bottlenecks were identified. Different facility configurations in terms of number of upstream trains were considered and the trade-off between their cost and ability to handle higher titers was analyzed. The case study insights demonstrate that the proposed modeling approach, combining MINLP models with visualization tools, is a valuable decision-support tool for the design of cost-effective facility configurations and to aid facility fit decisions. 2013.
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.
Exact solution of the two-axis countertwisting hamiltonian for the half-integer J case
NASA Astrophysics Data System (ADS)
Pan, Feng; Zhang, Yao-Zhong; Draayer, Jerry P.
2017-02-01
Bethe ansatz solutions of the two-axis countertwisting Hamiltonian for any (integer and half-integer) J are derived based on the Jordan–Schwinger (differential) boson realization of the SU(2) algebra after desired Euler rotations, where J is the total angular momentum quantum number of the system. It is shown that solutions to the Bethe ansatz equations can be obtained as zeros of the extended Heine–Stieltjes polynomials. Two sets of solutions, with solution number being J + 1 and J respectively when J is an integer and J + 1/2 each when J is a half-integer, are obtained. Properties of the zeros of the related extended Heine–Stieltjes polynomials for half-integer J cases are discussed. It is clearly shown that double degenerate level energies for half-integer J are symmetric with respect to the E = 0 axis. It is also shown that the excitation energies of the ‘yrast’ and other ‘yrare’ bands can all be asymptotically given by quadratic functions of J, especially when J is large.
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
Eisenhauer, Nico; Schädler, Martin
2011-02-01
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
Stochastic Semidefinite Programming: Applications and Algorithms
2012-03-03
doi: 2011/09/07 13:38:21 13 TOTAL: 1 Number of Papers published in non peer-reviewed journals: Baha M. Alzalg and K. A. Ariyawansa, Stochastic...symmetric programming over integers. International Conference on Scientific Computing, Las Vegas, Nevada, July 18--21, 2011. Baha M. Alzalg. On recent...Proceeding publications (other than abstracts): PaperReceived Baha M. Alzalg, K. A. Ariyawansa. Stochastic mixed integer second-order cone programming
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.
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.
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)
Truong, T. K.; Hsu, I. S.; Chang, J. J.; Shyu, H. C.; Reed, I. S.
1986-01-01
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.
Chang, Weng-Long
2012-03-01
Assume that n is a positive integer. If there is an integer such that M (2) ≡ C (mod n), i.e., the congruence has a solution, then C is said to be a quadratic congruence (mod n). If the congruence does not have a solution, then C is said to be a quadratic noncongruence (mod n). The task of solving the problem is central to many important applications, the most obvious being cryptography. In this article, we describe a DNA-based algorithm for solving quadratic congruence and factoring integers. In additional to this novel contribution, we also show the utility of our encoding scheme, and of the algorithm's submodules. We demonstrate how a variety of arithmetic, shifted and comparative operations, namely bitwise and full addition, subtraction, left shifter and comparison perhaps are performed using strands of DNA.
Property study of integer wavelet transform lossless compression coding based on lifting scheme
NASA Astrophysics Data System (ADS)
Xie, Cheng Jun; Yan, Su; Xiang, Yang
2006-01-01
In this paper the algorithms and its improvement of integer wavelet transform combining SPIHT and arithmetic coding in image lossless compression is mainly studied. The experimental result shows that if the order of low-pass filter vanish matrix is fixed, the improvement of compression effect is not evident when invertible integer wavelet transform is satisfied and focusing of energy property monotonic increase with transform scale. For the same wavelet bases, the order of low-pass filter vanish matrix is more important than the order of high-pass filter vanish matrix in improving the property of image compression. Integer wavelet transform lossless compression coding based on lifting scheme has no relation to the entropy of image. The effect of compression is depended on the the focuing of energy property of image transform.
Guseinov, Israfil; Mamedov, Bahtiyar
2002-09-01
The series expansion formulae are derived for the overlap integrals with arbitrary integer n and noninteger n* Slater-type orbitals (ISTOs and NISTOs) in terms of a product of well-known auxiliary functions A(sigma) and B (k). The series becomes an ordinary closed expression when both principal quantum numbers n* and n'* of orbitals are integer n*= n and n'*= n'. These formulae are especially useful for the calculation of overlap integrals for large quantum numbers. Accuracy of the results is satisfactory for values of integer and noninteger quantum numbers up to n= n'=60, n*= n'*<33 and for arbitrary values of screening constants of orbitals and internuclear distances.
Brunner, Thomas A.; Kalos, Malvin H.; Gentile, Nicholas A.
2005-03-01
Domain decomposed Monte Carlo codes, like other domain-decomposed codes, are difficult to debug. Domain decomposition is prone to error, and interactions between the domain decomposition code and the rest of the algorithm often produces subtle bugs. These bugs are particularly difficult to find in a Monte Carlo algorithm, in which the results have statistical noise. Variations in the results due to statistical noise can mask errors when comparing the results to other simulations or analytic results.
[Effect of cellulose-decomposing strain on microbial community of cow manure compost].
Liu, Jia; Li, Wan; Xu, Xiu-Hong; Li, Hong-Tao
2011-10-01
Taking the cow dung and straw as composting raw materials, effect of cellulose-decomposing strain on microbial community of cow manure compost was investigated with the traditional culture method and PCR-DGGE technique. The results showed that the microbiological inocula showed a more rapid rate of temperature elevation at the start of composting and prolonged the time of high-temperature process and increased the number of microbial. The DGGE map of cellulose-decomposing strain compost was different from natural compost, the succession of microbial community in cellulose-decomposing strain was faster than natural compost. Sequence comparison revealed that the Pseudomonas sp. of bacterial appeared at the initial stage and Acinetobacter sp., Flavobacteria were existed at the high-temperature process in natural compost; while Arthrobacter sp. was appeared at the high-temperature process in cellulose-decomposing strain compost. Bacillus sp. was dominant species at middle and later stage in natural compost and cellulose-decomposing strain compost. Eimeriidae of fungal appeared in compost materials, Aspergillus and thermophilic fungi were dominant species at the high-temperature process in natural compost and cellulose-decomposing strain compost. Ascomycota appeared at middle and later stage in natural compost; while Basidiomycetes in cellulose-decomposing strain compost. Aspergillus was found throughout the process. This result suggested that the microbiological inocula were able to facilitate the bacterial microbial diversity of the compost; reduced the fungal microbial diversity of the compost. The aims of this study were to provide a scientific basis to the diversity of microbial community by monitoring the dynamics of microbial community in cellulose-decomposing strain compost and represent an important step towards the understanding of microbiological inocula and its function in the degradation process of compost.
Development of Sulfuric Acid Decomposer for Thermo-Chemical IS Process
Hiroki, Noguchi; Hiroyuki, Ota; Atsuhiko, Terada; Shinji, Kubo; Kaoru, Onuki; Ryutaro, Hino
2006-07-01
The Japan Atomic Energy Agency (JAEA) has been conducting R and D on thermo-chemical Iodine-Sulfur (IS) process, which is one of most attractive water-splitting hydrogen production methods using nuclear heat of a high-temperature gas-cooled reactor (HTGR). In the IS process, sulfuric acid is evaporated and decomposed into H{sub 2}O and SO{sub 3} in a sulfuric acid decomposer operated under high temperature condition up to 500 deg C. Necessary heat is supplied by high temperature helium gas from the HTGR. Since the sulfuric acid decomposer will be exposed to severe corrosion condition, we have proposed a new decomposer concept of a block type heat exchanger made of SiC ceramic which has excellent corrosion and mechanical strength performance. To verify the concept, integrity of new type gaskets applied for boundary seal of the decomposer was examined as a first step. Pure gold gaskets coupled with absorption mechanism against thermal expansion showed good seal performance under 500 deg C. Based on this result, a mock-up model for a IS pilot-plant with 30 m{sup 3}/h-hydrogen production rate was test-fabricated as the next step. Through the fabrication and gas-tight tests, fabricability and structural integrity were confirmed. Also, the decomposer showed good mechanical strength and seal performances against horizontal loading simulating earthquake motion. (authors)
From Totally Unimodular to Balanced O, +-1 Matrices: A Family of Integer Polytopes,
1992-07-07
AD-A254 552I tl 1111111111111 liii II lllll From Totally Unimodular to Balanced 0,1 Matrices : A Family of Integer Polytopes Michele ConfortiI Gwrard... Matrices : A Family of Integer Polytopes Michele Conforti1 D T IC Gwrard Cornuwjols ’S ELECTE Klaus Truemper AUG24 1992 f SAU July 7, 1992 I This docunmcnt...and DMS-9000376. 1Dipartimento di Matematica Pura ed Applicata, Universiti di Padova, Via Belzoni 7, 35131 Padova, Italy. 2Carnegie Mellon University
Geng, Lingling; Yu, Yongguang; Zhang, Shuo
2016-09-01
In this paper, the function projective synchronization between integer-order and stochastic fractional-order nonlinear systems is investigated. Firstly, according to the stability theory of fractional-order systems and tracking control, a controller is designed. At the same time, based on the orthogonal polynomial approximation, the method of transforming stochastic error system into an equivalent deterministic system is given. Thus, the stability of the stochastic error system can be analyzed through its equivalent deterministic one. Finally, to demonstrate the effectiveness of the proposed scheme, the function projective synchronization between integer-order Lorenz system and stochastic fractional-order Chen system is studied.
Algorithm-Independent Framework for Verifying Integer Constraints
2007-11-02
TAL [7], Crary and Weirich [5]’s resource bound certifitation, Wang and Appel [16]’s safe garbage collection and an attempt at making the whole PCC...S. Weirich . Resource bound certification. In Proc. 27th Annual ACM SIGPLAN- SIGACT Symp. on Principles of Programming Languages. ACM Press, 2000. 30
Mixed-Integer Nonconvex Quadratic Optimization Relaxations and Performance Analysis
2016-10-11
portfolio deleveraging with market impact,” (Jingnan Chen, Liming Feng, Jiming Peng, Yinyu Ye), Operations Research, 62(1) (2014) 195-206. In this...Stanley 2012 Prize for Excellence in Financial Markets , First runner-up. “Space tensor conic programming,” (L Qi and Y Ye), Computational Optimization...portfolio deleveraging with market impact," (J. Chen, L. Feng, J. Peng, Y. Ye), Operations Research, 62(1) (2014) 195-206. "Simultaneous Beam Sampling
Partsch, Stephan; Milcu, Alexandru; Scheu, Stefan
2006-10-01
Decomposer invertebrates influence soil structure and nutrient mineralization as well as the activity and composition of the microbial community in soil and therefore likely affect plant performance and plant competition. We established model grassland communities in a greenhouse to study the interrelationship between two different functional groups of decomposer invertebrates, Lumbricidae and Collembola, and their effect on plant performance and plant nitrogen uptake in a plant diversity gradient. Common plant species of Central European Arrhenatherion grasslands were transplanted into microcosms with numbers of plant species varying from one to eight and plant functional groups varying from one to four. Separate and combined treatments with earthworms and collembolans were set up. Microcosms contained 15N labeled litter to track N fluxes into plant shoots. Presence of decomposers strongly increased total plant and plant shoot biomass. Root biomass decreased in the presence of collembolans and even more in the presence of earthworms. However, it increased when both animal groups were present. Also, presence of decomposers increased total N concentration and 15N enrichment of grasses, legumes, and small herbs. Small herbs were at a maximum in the combined treatment with earthworms and collembolans. The impact of earthworms and collembolans on plant performance strongly varied with plant functional group identity and plant species diversity and was modified when both decomposers were present. Both decomposer groups generally increased aboveground plant productivity through effects on litter decomposition and nutrient mineralization leading to an increased plant nutrient acquisition. The non-uniform effects of earthworms and collembolans suggest that functional diversity of soil decomposer animals matters and that the interactions between soil animal functional groups affect the structure of plant communities.
Motz, Benjamin A; Erickson, Molly A; Hetrick, William P
2013-04-01
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 430ms in a 1000ms 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 500ms in a 1000ms 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.
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…
The Effect of Learning Integers Using Cartoons on 7th Grade Students' Attitude to Mathematics
ERIC Educational Resources Information Center
Sengül, Sare; Dereli, Mehtap
2013-01-01
The purpose of this research is to investigate the effect on students' attitudes toward mathematics when cartoons are used in teaching integers. The research was designed in the form of a pre-test and post-test with a quasi experimental control group. The research participant group was composed of sixty-one (61) 7th grade students attending an…
Relationships between Prime-Rich Euler Type Equations and a Triangular Array of the Odd Integers,
1985-02-01
8217 Primitive ’ cell arrays are derived from the above array. Each such array consists of a prime value p(of c) which is substituted for every integer in the...relationships between the triangular array, the equations x squared - x + c, c=1,3,5,... and the derived primitive cell arrays are brought out. These show how
"It is Possible to Die Before Being Born". Negative Integers Subtraction: A Case Study
ERIC Educational Resources Information Center
Gallardo, Aurora
2003-01-01
A Case Study is presented in this article, where there is a contradiction between pre-algebraic language semantic and syntax used to solve word problems through a negative integers subtraction. Appendix includes answer key. (Contains 1 figure.) [For complete proceedings, see ED500859.
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.
Research on application for integer wavelet transform for lossless compression of medical image
NASA Astrophysics Data System (ADS)
Zhou, Zude; Li, Quan; Long, Quan
2003-09-01
This paper proposes an approach based on using lifting scheme to construct integer wavelet transform whose purpose is to realize the lossless compression of images. Then researches on application of medical image, software simulation of corresponding algorithm and experiment result are presented in this paper. Experiment shows that this method could improve the compression ration and resolution.
NASA Astrophysics Data System (ADS)
Huang, Jing; Zhu, Rihong
2009-08-01
A lossy to lossless three-dimensional (3D) compression of hyperspectral images is presented. On the spectral dimension, a low complexity reversible integer Karhunen-Loève transform (KLT) is used to fully exploit the spectral redundancy, while two-dimensional spatial combinative lifting algorithm (SCLA)-based integer wavelet transform is applied on the spatial dimension. At the low complexity KLT, the calculation processing of covariance matrix is carried out on a subset of vectors that is pseudorandomly selected from the complete set of spectral vectors. The transform matrix is factorized into triangular elementary reversible matrices (TERM) for reversible integer mapping and the lifting scheme is applied to implement integer KLT. The 3D asymmetric significance tree structure is then constructed from the 3D asymmetric orientation tree in 3D transformed domain. Each coefficient is then encoded by the significance test of the 3D asymmetric significance tree node at each bitplane instead of ordered lists to track the significance status of the tree or block sets and coefficients. This algorithm has low complexity and can be applied to lossy to lossless progressive transmission.
NASA Astrophysics Data System (ADS)
Tkachenko, Georgiy; Chen, Mingzhou; Dholakia, Kishan; Mazilu, Michael
2016-09-01
A photon can carry orbital angular momentum equal to an integer number of the reduced Planck's constant. This principle expresses itself in geometrical quantization of optical vortex beams, which thus can propagate only in the form of fields having a helically wavefront characterized by an integer valued topological charge. However, one can create an optical vortex beam of an effective fractional charge by combining multiple integer vortices. Here, we investigate this apparent violation of the geometrical quantization of orbital angular momentum of light. Our approach relies on observation of the light-induced motion of a microscopic particle, which thus acts as an optomechanical probe for the optical vortex beam. A fractional topological charge corresponds to an abrupt jump in the helical phase front of the beam. This singularity expresses itself as an off-axis disturbance in the intensity profile, and thus complicates the optomechanical probing. We overcome this problem by distributing the disturbance along the vortex ring, so that a microparticle can continuously orbit due to the orbital angular momentum transfer. We demonstrate theoretically that whatever effort is put into smoothing the fractional vortex ring (as long as the net topological charge is fixed), the particle's orbital motion cannot be as uniform as in the case of an integer vortex beam. We support this prediction by experimental proof. The experimental technique benefits from the recently introduced "perfect" vortex beams which allow an optically trapped particle to orbit along a constant trajectory irrespective of any topological charge.
ECG/PPG integer signal processing for a ubiquitous health monitoring system.
Shin, Woosik; Cha, Yong Dae; Yoon, Gilwon
2010-10-01
A compact ubiquitous-health monitor operated by single 8-bit microcontroller was made. An integer signal processing algorithm for this microcontroller was developed and digital filtering of ECG (electrocardiogram) and PPG (photoplethysmogram) was performed. Rounding-off errors due to integer operation was solved by increasing the number of effective integer digits during CPU operation; digital filter coefficients and data expressed in decimal points were multiplied by a certain number and converted into integers. After filter operation, the actual values were retrieved by dividing with the same number and selecting available highest bits. Our results showed comparable accuracies to those computed by a commercial software. Compared with a floating-point calculation by the same microcontroller, the computation speed became faster by 1.45 ∼ 2.0 times depending on various digital filtering cases. Our algorithm was successfully tested for remote health monitoring with multiple users. If our algorithm were not used, our health monitor should have used additional microcontrollers or DSP chip. The proposed algorithm reduced the size and cost of our health monitor substantially.
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.
2. QUANTUM HALL EFFECT: Hidden SU(4) symmetry in bilayer quantum well at integer filling factors
NASA Astrophysics Data System (ADS)
Fal'ko, V. I.; Iordanskii, S. V.; Kashuba, A. B.
2001-10-01
Phase diagram of a bilayer quantum well at integer filling factors is established using the hidden symmetry method. Three phases: ferromagnetic, canted antiferromagnetic (CAP) and spin-singlet, have been found. We confirm early results of Das Sarma et al. Each phase violates the SU(4) hidden symmetry and is stabilized by the anisotropy interactions.
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.
Microbial diversity, producer-decomposer interactions and ecosystem processes: a theoretical model.
Loreau, M
2001-02-07
Interactions between the diversity of primary producers and that of decomposers--the two key functional groups that form the basis of all ecosystems--might have major consequences on the functioning of depauperate ecosystems. I present a simple ecosystem model in which primary producers (plants) and decomposers (microbes) are linked through material cycling. The model considers a diversity of plant organic compounds and a diversity of microbial species. Nutrient recycling efficiency from organic compounds to decomposers is then the key parameter that controls ecosystem processes (primary productivity, secondary productivity, producer biomass and decomposer biomass). The model predicts that microbial diversity has a positive effect on nutrient recycling efficiency and ecosystem processes through either greater intensity of microbial exploitation of organic compounds or functional niche complementarity, much like in plants. Microbial niche breadth and overlap should not affect ecosystem processes unless they increase the number of organic compounds that are decomposed. In contrast, the model predicts that plant organic compound diversity can only have a negative effect or, at best, no effect on ecosystem processes, at least in a constant environment. This creates a tension between the effects of plant diversity and microbial diversity on ecosystem functioning, which may explain some recent experimental results.
Wallander, Håkan; Lindahl, Björn D; Nilsson, Lars Ola
2006-05-01
Transfer of (15)N between interacting mycelia of a wood-decomposing fungus (Hypholoma fasciculare) and an ectomycorrhizal fungus (Tomentellopsis submollis) was studied in a mature beech (Fagus sylvatica) forest. The amount of (15)N transferred from the wood decomposer to the ectomycorrhizal fungus was compared to the amount of (15)N released from the wood-decomposing mycelia into the soil solution as (15)N-NH(4). The study was performed in peat-filled plastic containers placed in forest soil in the field. The wood-decomposing mycelium was growing from an inoculated wood piece and the ectomycorrhizal mycelium from an introduced root from a mature tree. The containers were harvested after 41 weeks when physical contact between the two foraging mycelia was established. At harvest, (15)N content was analyzed in the peat (total N and (15)NH(4) (+)) and in the mycorrhizal roots. A limited amount of (15)N was transferred to the ectomycorrhizal fungus and this transfer could be explained by (15)NH(4) (+) released from the wood-decomposing fungus without involving any antagonistic interactions between the two mycelia. Using our approach, it was possible to study nutritional interactions between basidiomycete mycelia under field conditions and this and earlier studies suggest that the outcomes of such interactions are highly species-specific and depend on environmental conditions such as resource availability.
MicroCT detection of gunshot residue in fresh and decomposed firearm wounds.
Cecchetto, Giovanni; Amagliani, Alessandro; Giraudo, Chiara; Fais, Paolo; Cavarzeran, Fabiano; Montisci, Massimo; Feltrin, Giampietro; Viel, Guido; Ferrara, Santo Davide
2012-05-01
Gunshot residue (GSR) evidence may be altered or obscured by after-death events such as putrefaction, autolysis, and/or damage by animals. The present study aimed at evaluating and comparing the amount and differential distribution of GSR utilizing microcomputed tomography (microCT) analysis of fresh and decomposed gunshot wounds. A total of 60 experimental shootings at three different firing distances (5, 15, and 30 cm) were performed on human calves surgically amputated for medical reasons. Thirty specimens (10 for each tested distance) were immediately formalin-fixed, while the other 30 specimens were enclosed in a cowshed for 15 days, before formalin fixation (air temperature ranging from 11°C to 38°C). MicroCT analysis with three-dimensional image reconstruction detected GSR particles in all the investigated entrance wounds. In fresh specimens, GSR was concentrated on the skin surface around the entrance hole and in the epidermis and dermis layers around the cavity, while in decomposed specimens, the high density particles were detected only in the dermis layer. No GSR was detected in exit wounds of both fresh and decomposed specimens regardless of the tested firing distance. Statistical analysis demonstrated that also in decomposed wounds the amount of GSR roughly correlated with the distance from which the gun was fired, exhibiting, however, a higher variability than in fresh samples. The obtained results suggest that microCT analysis can be a valid screening tool for differentiating decomposed entrance and exit gunshot wounds.
A novel decomposition technique of friable asbestos by CHClF2-decomposed acidic gas.
Yanagisawa, Kazumichi; Kozawa, Takahiro; Onda, Ayumu; Kanazawa, Masazumi; Shinohara, Junichi; Takanami, Tetsuro; Shiraishi, Masatsugu
2009-04-30
Asbestos was widely used in numerous materials and building products due to their desirable properties. It is, however, well known that asbestos inhalation causes health damage and its inexpensive decomposition technique is necessary to be developed for pollution prevention. We report here an innovative decomposition technique of friable asbestos by acidic gas (HF and HCl) generated from the decomposition of CHClF(2) by the reaction with superheated steam at 800 degrees C. Chrysotile-asbestos fibers were completely decomposed to sellaite and magnesium silicofluoride hexahydrate by the reaction with CHClF(2)-decomposed acidic gas at 150 degrees C for 30 min. At high temperatures beyond 400 degrees C, sellaite and hematite were detected in the decomposed product. In addition, crocidolite containing wastes and amosite containing wastes were decomposed at 500 degrees C and 600 degrees C for 30 min, respectively, by CHClF(2)-decomposed acidic gas. The observation of the reaction products by phase-contrast microscopy (PCM) and scanning electron microscopy (SEM) confirmed that the resulting products did not contain any asbestos.
Mundorff, Amy Z; Vidoli, Giovanna; Melinek, Judy
2006-09-01
This case study demonstrates the importance of involving an anthropologist in forensic situations with decomposed remains. Anthropological consultation was used in conjunction with the comparison of antemortem and postmortem radiographs to establish positive identification of unknown, decomposed remains. The remains had no traditional identifying features such as fingerprints or dental. Through anthropological analysis, it was determined the decedent was male, between 20 and 23 years at time of death and c. 5'2'' tall. This information allowed for a presumptive identification and a request for antemortem radiographs. The missing person was identified comparing the spinous processes of the cervical and thoracic vertebrae between ante- and postmortem radiographs.
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.
Methods for assessing the impact of avermectins on the decomposer community of sheep pastures.
King, K L
1993-06-01
This paper outlines methods which can be used in the field assessment of potentially toxic chemicals such as the avermectins. The procedures focus on measuring the effects of the drug on decomposer organisms and the nutrient cycling process in pastures grazed by sheep. Measurements of decomposer activity are described along with methods for determining dry and organic matter loss and mineral loss from dung to the underlying soil. Sampling methods for both micro- and macro-invertebrates are discussed along with determination of the percentage infection of plant roots with vesicular-arbuscular mycorrhizal fungi. An integrated sampling unit for assessing the ecotoxicity of ivermectin in pastures grazed by sheep is presented.
NASA Astrophysics Data System (ADS)
Zhang, Xiaoxing; Cui, Hao; Gui, Yingang; Tang, Ju
2017-03-01
Carbon nanotubes (CNTs) have aroused extensive attentions as a new category of gas sensor materials owing to their outstanding performance for detecting specific gas among a variety of ones through diverse gas responses. This review summarizes the adsorption mechanism of CNTs and their properties related to the detection of sulfur hexafluoride (SF6) decomposed gases that generated in gas insulation switchgear (GIS) of power system. Their performances as sensors of both experimental analysis and theoretical calculation for various kinds of decomposed gases are summarized, and the further research trend on CNTs in the detection of SF6 decomposition components is also put forward.
Zhang, Xiaoxing; Cui, Hao; Gui, Yingang; Tang, Ju
2017-12-01
Carbon nanotubes (CNTs) have aroused extensive attentions as a new category of gas sensor materials owing to their outstanding performance for detecting specific gas among a variety of ones through diverse gas responses. This review summarizes the adsorption mechanism of CNTs and their properties related to the detection of sulfur hexafluoride (SF6) decomposed gases that generated in gas insulation switchgear (GIS) of power system. Their performances as sensors of both experimental analysis and theoretical calculation for various kinds of decomposed gases are summarized, and the further research trend on CNTs in the detection of SF6 decomposition components is also put forward.
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
The Neighborhood Covering Heuristic (NCH) Approach for the General Mixed Integer Programming Problem
2006-05-31
array of blade processors, specifically configured for parallel computation, possibly as a Beowulf cluster . Additional revenue, $65,000 per year, will...The AMIPS hardware, a multi- node clustered computer installation, will be networked with the COMPASS simulator hardware. Because of the unique
An integer linear programming approach for finding deregulated subgraphs in regulatory networks.
Backes, Christina; Rurainski, Alexander; Klau, Gunnar W; Müller, Oliver; Stöckel, Daniel; Gerasch, Andreas; Küntzer, Jan; Maisel, Daniela; Ludwig, Nicole; Hein, Matthias; Keller, Andreas; Burtscher, Helmut; Kaufmann, Michael; Meese, Eckart; Lenhof, Hans-Peter
2012-03-01
Deregulation of cell signaling pathways plays a crucial role in the development of tumors. The identification of such pathways requires effective analysis tools that facilitate the interpretation of expression differences. Here, we present a novel and highly efficient method for identifying deregulated subnetworks in a regulatory network. Given a score for each node that measures the degree of deregulation of the corresponding gene or protein, the algorithm computes the heaviest connected subnetwork of a specified size reachable from a designated root node. This root node can be interpreted as a molecular key player responsible for the observed deregulation. To demonstrate the potential of our approach, we analyzed three gene expression data sets. In one scenario, we compared expression profiles of non-malignant primary mammary epithelial cells derived from BRCA1 mutation carriers and of epithelial cells without BRCA1 mutation. Our results suggest that oxidative stress plays an important role in epithelial cells of BRCA1 mutation carriers and that the activation of stress proteins may result in avoidance of apoptosis leading to an increased overall survival of cells with genetic alterations. In summary, our approach opens new avenues for the elucidation of pathogenic mechanisms and for the detection of molecular key players.
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.
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.
A Mixed Integer Programming Model for Improving Theater Distribution Force Flow Analysis
2013-03-01
the introduction to LINGO in OPER 510. Next, I wish to thank LINDO Systems, particularly Kevin Cunningham, for software assistance with LINGO . I...viii Appendix A. LINGO 13 Settings File Contents .............................................................. 79 Appendix B. Additional Model...optimization software LINGO 13 (Lindo Systems Inc, 2012). A Decision Support System was built in the Excel environment where the user uploads a
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…
2009-03-01
their sensing strategies. Creating this strategy is very difficult for a number of reasons. First and foremost, the number of available weather...computer code is written in Visual Basic (VBA®) for Microsoft Excel® with an emphasis on minimizing the number of decision variables at each step...resolution, this could mean performing this analysis for a very large number of 225 km2 roughly square-shaped climatological regions. For an average
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…
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
Apaydin, Mehmet Serkan; Çatay, Bülent; Patrick, Nicholas; Donald, Bruce R
2011-05-01
Nuclear magnetic resonance (NMR) spectroscopy is an important experimental technique that allows one to study protein structure and dynamics in solution. An important bottleneck in NMR protein structure determination is the assignment of NMR peaks to the corresponding nuclei. Structure-based assignment (SBA) aims to solve this problem with the help of a template protein which is homologous to the target and has applications in the study of structure-activity relationship, protein-protein and protein-ligand interactions. We formulate SBA as a linear assignment problem with additional nuclear overhauser effect constraints, which can be solved within nuclear vector replacement's (NVR) framework (Langmead, C., Yan, A., Lilien, R., Wang, L. and Donald, B. (2003) A Polynomial-Time Nuclear Vector Replacement Algorithm for Automated NMR Resonance Assignments. Proc. the 7th Annual Int. Conf. Research in Computational Molecular Biology (RECOMB), Berlin, Germany, April 10-13, pp. 176-187. ACM Press, New York, NY. J. Comp. Bio., (2004), 11, pp. 277-298; Langmead, C. and Donald, B. (2004) An expectation/maximization nuclear vector replacement algorithm for automated NMR resonance assignments. J. Biomol. NMR, 29, 111-138). Our approach uses NVR's scoring function and data types and also gives the option of using CH and NH residual dipolar coupling (RDCs), instead of NH RDCs which NVR requires. We test our technique on NVR's data set as well as on four new proteins. Our results are comparable to NVR's assignment accuracy on NVR's test set, but higher on novel proteins. Our approach allows partial assignments. It is also complete and can return the optimum as well as near-optimum assignments. Furthermore, it allows us to analyze the information content of each data type and is easily extendable to accept new forms of input data, such as additional RDCs.
Solving a Class of Stochastic Mixed-Integer Programs With Branch and Price
2006-01-01
model is called the (deter- ministic) capacitated facility-location problem with sole-sourcing (FLP) ( Barcelo and Casanova [5]). Assume now that some...Appelgren, L.H.: A column generation algorithm for a ship scheduling problem. Transp. Sci. 3, 53–68 (1969) 5. Barcelo , J., Casanova, J.: A heuristic
1989-12-01
profiles pay[] hourly wage rate for operators on machine m */ FILE * infp ,*outfpl,*outfp2,*outfp3,*outfp4,*outfp5,*outfp6,*fopen(; main () { /* open I/O...files and assign pointers */ infp =fopen("GMFA.DAT","r"); outfp5=fopen( "XL5.DAT’","w"); /* read in input stream data from "GHFA.DAT" * rddstrm...and closing the files */ /* * fprintf(outfp4,"$ MAXIMIZE IITWSTS\
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…
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…
Draft Genome Sequence of the Lignocellulose Decomposer Thermobifida fusca Strain TM51.
Tóth, Akos; Barna, Terézia; Nagy, István; Horváth, Balázs; Nagy, István; Táncsics, András; Kriszt, Balázs; Baka, Erzsébet; Fekete, Csaba; Kukolya, József
2013-07-11
Here, we present the complete genome sequence of Thermobifida fusca strain TM51, which was isolated from the hot upper layer of a compost pile in Hungary. T. fusca TM51 is a thermotolerant, aerobic actinomycete with outstanding lignocellulose-decomposing activity.
Plant-herbivore-decomposer stoichiometric mismatches and nutrient cycling in ecosystems.
Cherif, Mehdi; Loreau, Michel
2013-03-07
Plant stoichiometry is thought to have a major influence on how herbivores affect nutrient availability in ecosystems. Most conceptual models predict that plants with high nutrient contents increase nutrient excretion by herbivores, in turn raising nutrient availability. To test this hypothesis, we built a stoichiometrically explicit model that includes a simple but thorough description of the processes of herbivory and decomposition. Our results challenge traditional views of herbivore impacts on nutrient availability in many ways. They show that the relationship between plant nutrient content and the impact of herbivores predicted by conceptual models holds only at high plant nutrient contents. At low plant nutrient contents, the impact of herbivores is mediated by the mineralization/immobilization of nutrients by decomposers and by the type of resource limiting the growth of decomposers. Both parameters are functions of the mismatch between plant and decomposer stoichiometries. Our work provides new predictions about the impacts of herbivores on ecosystem fertility that depend on critical interactions between plant, herbivore and decomposer stoichiometries in ecosystems.
Tong, Dong-li; Shuang, Sheng-qing; Li, Xiao-jun; Deng, Wan-rong; Zhao, Ran-ran; Jia, Chun-yun; Gong, Zong-qiang
2015-08-01
Batch experiments were conducted to investigate the effect of soluble and insoluble decomposing products (decomposed for 1 day and 120 day; noted by DP1 and DP120, respectively) from immobilized carriers (corncob) on the desorption of pyrene in PAH-contaminated soil (120 d ageing, 20 mg x kg(-1)). It was found that (1) adding decomposing products of immobilized carriers could not only increase the rapidly desorbing fraction, but also improve the desorption rate of pyrene. The desorption rates of pyrene increased from 20% to 81.8% and 84.5% because of adding insoluble DP1 and DP120, and from 40% to 89.6% and 88.5% because of adding soluble DP1 and DP120. (2) The sorption amounts of pyrene by insoluble DP1 and.DP120 were 9. 4 and 16. 6 times higher than that by natural corncob, respectively. The sorption amounts of XAD-2 resins were increased by 1.5 and 3.1 times due to the added soluble DP1 and DP120, respectively. These results indicated that decomposing products of immobilized carries could improve the desorption of pyrene by sorption or activation in contaminated soil.
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)
Tamma, Vincenzo
2016-12-01
We describe a novel analogue algorithm that allows the simultaneous factorization of an exponential number of large integers with a polynomial number of experimental runs. It is the interference-induced periodicity of "factoring" interferograms measured at the output of an analogue computer that allows the selection of the factors of each integer. At the present stage, the algorithm manifests an exponential scaling which may be overcome by an extension of this method to correlated qubits emerging from n-order quantum correlations measurements. We describe the conditions for a generic physical system to compute such an analogue algorithm. A particular example given by an "optical computer" based on optical interference will be addressed in the second paper of this series (Tamma in Quantum Inf Process 11128:1189, 2015).
Non-Porod scattering and non-integer scaling of resistance in rough films
NASA Astrophysics Data System (ADS)
Bupathy, Arunkumar; Verma, Rupesh; Banerjee, Varsha; Puri, Sanjay
2017-04-01
In many physical systems, films are rough due to the stochastic behavior of depositing particles. They are characterized by non-Porod power law decays in the structure factor S (k) . Theoretical studies predict anomalous diffusion in such morphologies, with important implications for diffusivity, conductivity, etc. We use the non-Porod decay to accurately determine the fractal properties of two prototypical nanoparticle films: (i) Palladium (Pd) and (ii) Cu2O. Using scaling arguments, we find that the resistance of rough films of lateral size L obeys a non-integer power law R ∼L-ζ , in contrast to integer power laws for compact structures. The exponent ζ is anisotropic. We confirm our predictions by re-analyzing experimental data from Cu2O nano-particle films. Our results are valuable for understanding recent experiments that report anisotropic electrical properties in (rough) thin films.
Joint demosaicking and integer-ratio downsampling algorithm for color filter array image
NASA Astrophysics Data System (ADS)
Lee, Sangyoon; Kang, Moon Gi
2015-03-01
This paper presents a joint demosacking and integer-ratio downsampling algorithm for color filter array (CFA) images. Color demosaicking is a necessary part of image signal processing to obtain full color image for digital image recording system using single sensor. Also, such as mobile devices, the obtained image from sensor has to be downsampled to be display because the resolution of display is smaller than that of image. The conventional method is "Demosaicking first and downsampling later". However, this procedure requires a significant hardware resources and computational cost. In this paper, we proposed a method in which demosaicking and downsampling are working simultaneously. We analyze the Bayer CFA image in frequency domain, and then joint demosaicking and downsampling with integer-ratio scheme based on signal decomposition of luma and chrominance components. Experimental results show that the proposed method produces the high quality performance with much lower com putational cost and less hardware resources.
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.
Integer quantum magnon Hall plateau-plateau transition in a spin-ice model
NASA Astrophysics Data System (ADS)
Xu, Baolong; Ohtsuki, Tomi; Shindou, Ryuichi
2016-12-01
Low-energy magnon bands in a two-dimensional spin-ice model become integer quantum magnon Hall bands under an out-of-plane field. By calculating the localization length and the two-terminal conductance of magnon transport, we show that the magnon bands with disorders undergo a quantum phase transition from an integer quantum magnon Hall regime to a conventional magnon localized regime. Finite size scaling analysis as well as a critical conductance distribution shows that the quantum critical point belongs to the same universality class as that in the quantum Hall transition. We characterize thermal magnon Hall conductivity in a disordered quantum magnon Hall system in terms of robust chiral edge magnon transport.
Ground state energy of a non-integer number of particles with δ attractive interactions
NASA Astrophysics Data System (ADS)
Brunet, Éric; Derrida, Bernard
2000-04-01
We show how to define and calculate the ground state energy of a system of quantum particles with δ attractive interactions when the number of particles n is non-integer. The question is relevant to obtain the probability distribution of the free energy of a directed polymer in a random medium. When one expands the ground state energy in powers of the interaction, all the coefficients of the perturbation series are polynomials in n, allowing to define the perturbation theory for non-integer n. We develop a procedure to calculate all the cumulants of the free energy of the directed polymer and we give explicit, although complicated, expressions of the first three cumulants.
NASA Astrophysics Data System (ADS)
Tamma, Vincenzo
2016-12-01
We report a detailed analysis of the optical realization of the analogue algorithm described in the first paper of this series (Tamma in Quantum Inf Process 11128:1190, 2015) for the simultaneous factorization of an exponential number of integers. Such an analogue procedure, which scales exponentially in the context of first-order interference, opens up the horizon to polynomial scaling by exploiting multi-particle quantum interference.
Pattern-based integer sample motion search strategies in the context of HEVC
NASA Astrophysics Data System (ADS)
Maier, Georg; Bross, Benjamin; Grois, Dan; Marpe, Detlev; Schwarz, Heiko; Veltkamp, Remco C.; Wiegand, Thomas
2015-09-01
The H.265/MPEG-H High Efficiency Video Coding (HEVC) standard provides a significant increase in coding efficiency compared to its predecessor, the H.264/MPEG-4 Advanced Video Coding (AVC) standard, which however comes at the cost of a high computational burden for a compliant encoder. Motion estimation (ME), which is a part of the inter-picture prediction process, typically consumes a high amount of computational resources, while significantly increasing the coding efficiency. In spite of the fact that both H.265/MPEG-H HEVC and H.264/MPEG-4 AVC standards allow processing motion information on a fractional sample level, the motion search algorithms based on the integer sample level remain to be an integral part of ME. In this paper, a flexible integer sample ME framework is proposed, thereby allowing to trade off significant reduction of ME computation time versus coding efficiency penalty in terms of bit rate overhead. As a result, through extensive experimentation, an integer sample ME algorithm that provides a good trade-off is derived, incorporating a combination and optimization of known predictive, pattern-based and early termination techniques. The proposed ME framework is implemented on a basis of the HEVC Test Model (HM) reference software, further being compared to the state-of-the-art fast search algorithm, which is a native part of HM. It is observed that for high resolution sequences, the integer sample ME process can be speed-up by factors varying from 3.2 to 7.6, resulting in the bit-rate overhead of 1.5% and 0.6% for Random Access (RA) and Low Delay P (LDP) configurations, respectively. In addition, the similar speed-up is observed for sequences with mainly Computer-Generated Imagery (CGI) content while trading off the bit rate overhead of up to 5.2%.
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.
Lossless image compression with projection-based and adaptive reversible integer wavelet transforms.
Deever, Aaron T; Hemami, Sheila S
2003-01-01
Reversible integer wavelet transforms are increasingly popular in lossless image compression, as evidenced by their use in the recently developed JPEG2000 image coding standard. In this paper, a projection-based technique is presented for decreasing the first-order entropy of transform coefficients and improving the lossless compression performance of reversible integer wavelet transforms. The projection technique is developed and used to predict a wavelet transform coefficient as a linear combination of other wavelet transform coefficients. It yields optimal fixed prediction steps for lifting-based wavelet transforms and unifies many wavelet-based lossless image compression results found in the literature. Additionally, the projection technique is used in an adaptive prediction scheme that varies the final prediction step of the lifting-based transform based on a modeling context. Compared to current fixed and adaptive lifting-based transforms, the projection technique produces improved reversible integer wavelet transforms with superior lossless compression performance. It also provides a generalized framework that explains and unifies many previous results in wavelet-based lossless image compression.
NASA Astrophysics Data System (ADS)
Yan, Jingwen; Chen, Jiazhen
2007-03-01
A new hyperspectral image compression method of spectral feature classification vector quantization (SFCVQ) and embedded zero-tree of wavelet (EZW) based on Karhunen-Loeve transformation (KLT) and integer wavelet transformation is represented. In comparison with the other methods, this method not only keeps the characteristics of high compression ratio and easy real-time transmission, but also has the advantage of high computation speed. After lifting based integer wavelet and SFCVQ coding are introduced, a system of nearly lossless compression of hyperspectral images is designed. KLT is used to remove the correlation of spectral redundancy as one-dimensional (1D) linear transform, and SFCVQ coding is applied to enhance compression ratio. The two-dimensional (2D) integer wavelet transformation is adopted for the decorrelation of 2D spatial redundancy. EZW coding method is applied to compress data in wavelet domain. Experimental results show that in comparison with the method of wavelet SFCVQ (WSFCVQ), the method of improved BiBlock zero tree coding (IBBZTC) and the method of feature spectral vector quantization (FSVQ), the peak signal-to-noise ratio (PSNR) of this method can enhance over 9 dB, and the total compression performance is improved greatly.
Gentile, N A; Kalos, M H; Brunner, T A
2005-03-22
Domain decomposed Monte Carlo codes, like other domain-decomposed codes, are difficult to debug. Domain decomposition is prone to error, and interactions between the domain decomposition code and the rest of the algorithm often produces subtle bugs. These bugs are particularly difficult to find in a Monte Carlo algorithm, in which the results have statistical noise. Variations in the results due to statistical noise can mask errors when comparing the results to other simulations or analytic results. If a code can get the same result on one domain as on many, debugging the whole code is easier. This reproducibility property is also desirable when comparing results done on different numbers of processors and domains. We describe how reproducibility, to machine precision, is obtained on different numbers of domains in an Implicit Monte Carlo photonics code.
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.
Li, Ning; Cao, Jinde; Hayat, Tasawar
2014-08-01
This paper is concerned with a class of nonlinear uncertain switched networks with discrete time-varying delays . Based on the strictly complete property of the matrices system and the delay-decomposing approach, exploiting a new Lyapunov-Krasovskii functional decomposing the delays in integral terms, the switching rule depending on the state of the network is designed. Moreover, by piecewise delay method, discussing the Lyapunov functional in every different subintervals, some new delay-dependent robust stability criteria are derived in terms of linear matrix inequalities, which lead to much less conservative results than those in the existing references and improve previous results. Finally, an illustrative example is given to demonstrate the validity of the theoretical results.
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.
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.
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
Attitude estimation of earth orbiting satellites by decomposed linear recursive filters
NASA Technical Reports Server (NTRS)
Kou, S. R.
1975-01-01
Attitude estimation of earth orbiting satellites (including Large Space Telescope) subjected to environmental disturbances and noises was investigated. Modern control and estimation theory is used as a tool to design an efficient estimator for attitude estimation. Decomposed linear recursive filters for both continuous-time systems and discrete-time systems are derived. By using this accurate estimation of the attitude of spacecrafts, state variable feedback controller may be designed to achieve (or satisfy) high requirements of system performance.
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.
Utilization of prey from the decomposer system by generalist predators of grassland.
Oelbermann, Katja; Langel, Reinhard; Scheu, Stefan
2008-03-01
We investigated the linkage between the detrital subsystem and generalist predators of meadow ecosystems by manipulating prey availability in two different ways: we increased resource availability for the decomposer subsystem and thereby decomposer prey by adding mulch materials (detritus enhancement), and we added fruitflies (Drosophila melanogaster, Diptera; prey enhancement) to fenced plots. Both supplemented materials significantly differed in their (13)C/(12)C and (15)N/(14)N ratios from those of the natural litter. We measured density responses of detritivorous, herbivorous and predaceous arthropods to the increased resource supply. We used ratios of natural stable isotopes of N and C in arthropod tissues to trace the flux from the added resources to consumers and to relate density responses of consumers to changes in resource supply. Effects of resource enhancement propagated through at least two trophic levels, resulting in higher densities of major decomposer and predator taxa. Effects of detritus enhancement were much stronger than those of prey enhancement. Signatures of delta(13)C proved density responses of Collembola taxa to be related to the added mulch materials. Among generalist predators, densities of juvenile wolf spiders (Lycosidae) responded more to detritus-enhancement than to prey-enhancement treatments. In contrast, the density of the web-building linyphiid and the non-web gnaphosid spiders remained unaffected. Each spider taxon, including those which did not respond numerically, was significantly enriched in (13)C in detritus-enhancement treatments, suggesting that they gain energy from the decomposer system. Numbers of herbivores-cicadellids and aphids-were similar in each of the treatments, indicating that they were unaffected by changes in predator density. Our results indicate that the lack of a numerical response to resource supplementation is not necessarily due to the absence of a trophic linkage, but may be caused by compensatory
Approach to calculate normal modes by decomposing the dyadic Green's function.
Yu, Wenhai; Yue, Wencheng; Yao, Peijun; Lu, Yonghua; Liu, Wen
2014-11-03
Normal mode is a very fundamental notion in quantum and classical optics. In this paper, we present a method to calculate normal modes by decomposing dyadic Green's function, where the modes are excited by dipoles. The modes obtained by our method can be directly normalized and their degeneracies can be easily removed. This method can be applied to many theoretical descriptions of cavity electrodynamics and is of interest to nanophotonics.
The effect of lignin photodegradation on decomposability of Calamagrostis epigeios grass litter.
Frouz, Jan; Cajthaml, Tomáš; Mudrák, Ondřej
2011-11-01
The common grass Calamagrostis epigeions produces a large amount of dead biomass, which remain above the soil surface for many months. In this study, we determined how exposure of dead biomass above the soil affects its subsequent decomposition in soil. Collected dead standing biomass was divided in two parts, the first one (initial litter) was stored in a dark, dry place. The other part was placed in litterbags in the field. The litterbags were located in soil, on the soil surface, or hanging in the air without contact with soil but exposed to the sun and rain. After 1 year of field exposure, litter mass loss and C and N content were measured, and changes in litter chemistry were explored using NMR and thermochemolysis-GC-MS. The potential decomposability of the litter was quantified by burying the litter from the litterbags and the initial litter in soil microcosms and measuring soil respiration. Soil respiration was greater with litter that had been hanging in air than with all other kinds of litter. These finding could not be explained by changes in litter mass or C:N ratio. NMR indicated a decrease in polysaccharides relative to lignin in litter that was buried in soil but not in litter that was placed on soil surface or that was hanging in the air. Thermochemolysis indicated that the syringyl units of the litter lignin were decomposed when the litter was exposed to light. We postulate that photochemical decay of lignin increase decomposability of dead standing biomass.
An initial study of insect succession on decomposing rabbit carrions in Harare, Zimbabwe
Mabika, Nyasha; Masendu, Ron; Mawera, Gilbert
2014-01-01
Objective To investigate insects visiting sun exposed and shaded decomposing rabbit carcasses and to establish the relationship between insects and carcasses which may be of forensic importance in Harare. Methods Two rabbits weighing 2.3 kg and 2.5 kg were killed by sharp blows on the head. One was exposed to the sun while the other was placed under shade. The carcasses were allowed to decompose and insects were collected twice a day for the first week and thereafter once a day up to the end of the 7 weeks. Maggots were also collected from the decomposing carcasses and reared. Results Five dipteran families (Calliphoridae, Muscidae, Sarcophagidae, Phoridae and Drosophilidae) were identified from the sun-exposed carcass. Species collected included Lucilia cuprina (L. cuprina), Chrysomya albiceps (C. albiceps), Musca domestica, Sarcophaga sp. and Drosophila sp. Four families (Calliphoridae, Muscidae, Phoridae, Anthomyiidae) were identified from the shaded carcass. Representatives of these families included L. cuprina, C. albiceps, Musca domestica, and Hydrotaea sp. Three Coleopteran families (Histeridae, Cleridae and Dermestidae) were identified from both carcasses. The observed species were Saprinus sp., Necrobia rufipes and Dermestes sp. Formicidae (Hymenoptera) was represented by only one species (Pheidole sp.). Flies which emerged from the rearing units were L. cuprina, Lucilia sp., C. albiceps, Sarcophaga sp. and Sepsis sp.). Conclusions Of the dipteran species collected during the study, L. cuprina and C. albiceps could be important for further forensic studies since they were collected from the carcasses and also observed from the rearing units. PMID:25183277
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.
Ecotoxicological impact of the fungicide tebuconazole on an aquatic decomposer-detritivore system.
Zubrod, Jochen P; Bundschuh, Mirco; Feckler, Alexander; Englert, Dominic; Schulz, Ralf
2011-12-01
Leaf litter breakdown is a fundamental process in aquatic ecosystems that is realized by microbial decomposers and invertebrate detritivores. Although this process may be adversely affected by fungicides, among other factors, no test design exists to assess combined effects on such decomposer-detritivore systems. Hence, the present study assessed effects of the model fungicide tebuconazole (65 µg/L) on the conditioning of leaf material (by characterizing the associated microbial community) as well as the combined effects (i.e., direct toxicity and food quality-related effects (=indirect)) on the energy processing of the leaf-shredding amphipod Gammarus fossarum using a five-week semistatic test design. Gammarids exposed to tebuconazole produced significantly less feces (≈ 20%), which in turn significantly increased their assimilation (≈ 30%). Moreover, a significantly reduced lipid content (≈ 20%) indicated lower physiological fitness. The conditioning process was altered as well, which was indicated by a significantly reduced fungal biomass (≈ 40%) and sporulation (≈ 30%) associated with the leaf material. These results suggest that tebuconazole affects both components of the investigated decomposer-detritivore system. However, adverse effects on the level of detritivores cannot be explicitly attributed to direct or indirect pathways. Nevertheless, as the endpoints assessed are directly related to leaf litter breakdown and associated energy transfer processes, the protectiveness of environmental risk assessment for this ecosystem function may be more realistically assessed in future studies by using this or comparable test designs.
Voss, Sasha C; Spafford, Helen; Dadour, Ian R
2009-12-15
This study considered annual, seasonal and shorter term variation in patterns of insect succession onto decomposing remains at two contrasting locations in Western Australia, bushland and agricultural. The degree of consistency in insect succession patterns over spatial and temporal scales was evaluated through multivariate analysis of occurrence-based distance matrices. Insect assemblages were strongly correlated between locations, within corresponding time periods, indicating that patterns of insect succession were similar between localised sites within the same broad geographic area. This suggests that there is reasonable scope for the application of baseline succession data generated at a single study site to a range of decomposition sites within a given region. Differences were largely due to species absences at the agricultural site. Three species of Coleoptera were identified as possible representatives of bushland habitat, Ptomaphila lacrymosa (Silphidae), Omorgus tatei (Trogidae) and Helea castor (Tenebrionidae), and may be indicative of post mortem movement between habitat types. Within locations, variation in insect assemblages was not significant between years. Within years, insect assemblages varied significantly over time on a seasonal time scale and as decomposition progressed through defined decomposition stages. Forensically relevant data detailing the seasonal pattern of insect succession onto decomposing remains for Western Australia are reported. Additional focus has been directed towards hymenopteran parasitoids that frequent decomposing remains and parasitise Diptera colonisers. Parasitoids can be used to provide an extended PMI timeframe in cases where traditional forensic indicators have completed their development.
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
Pulsed field gradient multiple-quantum MAS NMR spectroscopy of half-integer spin quadrupolar nuclei
NASA Astrophysics Data System (ADS)
Fyfe, C. A.; Skibsted, J.; Grondey, H.; Meyer zu Altenschildesche, H.
1997-12-01
Pulsed field gradients (PFGs) have been applied to select coherence transfer pathways in multiple-quantum (MQ) MAS NMR spectra of half-integer spin quadrupolar nuclei in rigid solids. 27Al triple-quantum (3Q) MAS NMR spectra of the aluminophosphate molecular sieves VPI-5 and AlPO 4-18 have been used to demonstrate the selection of the (0)→(3)→(-1) coherence transfer pathway using PFGs and no phase cycling. Compared to MQMAS experiments that employ phase cycling schemes, the main advantage of the PFG-MQMAS technique is its simplicity, which should facilitate the combination of MQMAS with other pulse sequences.
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.
On Random Matrix Averages Involving Half-Integer Powers of GOE Characteristic Polynomials
NASA Astrophysics Data System (ADS)
Fyodorov, Y. V.; Nock, A.
2015-05-01
Correlation functions involving products and ratios of half-integer powers of characteristic polynomials of random matrices from the Gaussian orthogonal ensemble (GOE) frequently arise in applications of random matrix theory (RMT) to physics of quantum chaotic systems, and beyond. We provide an explicit evaluation of the large- limits of a few non-trivial objects of that sort within a variant of the supersymmetry formalism, and via a related but different method. As one of the applications we derive the distribution of an off-diagonal entry of the resolvent (or Wigner -matrix) of GOE matrices which, among other things, is of relevance for experiments on chaotic wave scattering in electromagnetic resonators.
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.
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.
NASA Astrophysics Data System (ADS)
Luo, Zhen; Martonosi, Margaret
1998-10-01
This paper proposes and evaluates an approach for improving the performance of arithmetic calculations via delayed addition. Our approach employs the idea used in Wallace trees to delay addition until the end of a repeated calculation such as accumulation or dot-product; this effectively removes carry propagation overhead from the calculation's critical path. We present imager and floating- point designs that use this technique. Our pipelined integer multiply-accumulate design is based on a fairly traditional multiplier design, but with delayed addition as well. This design achieves a 37 MHz clock rate on an XC4036XL-2 FPGA. Next, we present a 32-bit floating-point accumulator based on delayed addition. Here delayed addition requires a novel alignment technique that decouples the incoming operands from the accumulated result. A conservative version of this design achieves a 33 MHz clock rate. Finally, we also present a more aggressive 32-bit floating-point accumulator design that achieves a 66 MHz clock rate. These designs demonstrate the utility of delayed addition for accelerating FPGA calculations in both the integer and floating-point domains.
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.
Dynamically sculpturing plasmonic vortices: from integer to fractional orbital angular momentum
Wang, Yu; Zhao, Peng; Feng, Xue; Xu, Yuntao; Liu, Fang; Cui, Kaiyu; Zhang, Wei; Huang, Yidong
2016-01-01
As a fundamental tool for light-matter interactions, plasmonic vortex (PV) is extremely useful due to the unique near field property. However, it is a pity that, up to now, the orbital angular momentum (OAM) carried by PVs could not be dynamically and continuously tuned in practice as well as the properties of fractional PVs are still not well investigated. By comparing with two previously reported methods, it is suggested that our proposal of utilizing the propagation induced radial phase gradient of incident Laguerre-Gaussian (LG) beam is a promising candidate to sculpture PVs from integer to fractional OAM dynamically. Consequently, the preset OAM of PVs could have four composing parts: the incident spin and orbital angular momentum, the geometric contribution of chiral plasmonic structure, and the radial phase gradient dependent contribution. Moreover, an analytical expression for the fractional PV is derived as a linear superposition of infinite numbers of integer PVs described by Bessel function of the first kind. It is also shown that the actual mean OAM of a fractional PV would deviate from the preset value, which is similar with previous results for spatial fractional optical vortices. PMID:27811986
Dynamically sculpturing plasmonic vortices: from integer to fractional orbital angular momentum
NASA Astrophysics Data System (ADS)
Wang, Yu; Zhao, Peng; Feng, Xue; Xu, Yuntao; Liu, Fang; Cui, Kaiyu; Zhang, Wei; Huang, Yidong
2016-11-01
As a fundamental tool for light-matter interactions, plasmonic vortex (PV) is extremely useful due to the unique near field property. However, it is a pity that, up to now, the orbital angular momentum (OAM) carried by PVs could not be dynamically and continuously tuned in practice as well as the properties of fractional PVs are still not well investigated. By comparing with two previously reported methods, it is suggested that our proposal of utilizing the propagation induced radial phase gradient of incident Laguerre-Gaussian (LG) beam is a promising candidate to sculpture PVs from integer to fractional OAM dynamically. Consequently, the preset OAM of PVs could have four composing parts: the incident spin and orbital angular momentum, the geometric contribution of chiral plasmonic structure, and the radial phase gradient dependent contribution. Moreover, an analytical expression for the fractional PV is derived as a linear superposition of infinite numbers of integer PVs described by Bessel function of the first kind. It is also shown that the actual mean OAM of a fractional PV would deviate from the preset value, which is similar with previous results for spatial fractional optical vortices.
A Simplified Integer Cosine Transform and Its Application in Image Compression
NASA Astrophysics Data System (ADS)
Costa, M.; Tong, K.
1994-07-01
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 pre-compensate for the factor approximations in the inverse ICT operation, to be performed in real time, at a large number of low-cost receivers.
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.
Cumulative Poisson Distribution Program
NASA Technical Reports Server (NTRS)
Bowerman, Paul N.; Scheuer, Ernest M.; Nolty, Robert
1990-01-01
Overflow and underflow in sums prevented. Cumulative Poisson Distribution Program, CUMPOIS, one of two computer programs that make calculations involving cumulative Poisson distributions. Both programs, CUMPOIS (NPO-17714) and NEWTPOIS (NPO-17715), used independently of one another. CUMPOIS determines cumulative Poisson distribution, used to evaluate cumulative distribution function (cdf) for gamma distributions with integer shape parameters and cdf for X (sup2) distributions with even degrees of freedom. Used by statisticians and others concerned with probabilities of independent events occurring over specific units of time, area, or volume. Written in C.
Newton/Poisson-Distribution Program
NASA Technical Reports Server (NTRS)
Bowerman, Paul N.; Scheuer, Ernest M.
1990-01-01
NEWTPOIS, one of two computer programs making calculations involving cumulative Poisson distributions. NEWTPOIS (NPO-17715) and CUMPOIS (NPO-17714) used independently of one another. NEWTPOIS determines Poisson parameter for given cumulative probability, from which one obtains percentiles for gamma distributions with integer shape parameters and percentiles for X(sup2) distributions with even degrees of freedom. Used by statisticians and others concerned with probabilities of independent events occurring over specific units of time, area, or volume. Program written in C.
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.
NASA Astrophysics Data System (ADS)
Jiao, Yi; Duan, Zhe
2017-01-01
In a diffraction-limited storage ring, half integer resonances can have strong effects on the beam dynamics, associated with the large detuning terms from the strong focusing and strong sextupoles as required for an ultralow emittance. In this study, the limitation of half integer resonances on the available momentum acceptance (MA) was statistically analyzed based on one design of the High Energy Photon Source (HEPS). It was found that the probability of MA reduction due to crossing of half integer resonances is closely correlated with the level of beta beats at the nominal tunes, but independent of the error sources. The analysis indicated that for the presented HEPS lattice design, the rms amplitude of beta beats should be kept below 1.5% horizontally and 2.5% vertically to reach a small MA reduction probability of about 1%.
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...
ERIC Educational Resources Information Center
Goodrow, Anne M.; Kidd, Kasia
2008-01-01
This article looks at how the activity of decomposing number--having students write numerical expressions equivalent to the number of days in school--can help students develop understanding of place value. (Contains 3 figures.)
Vilas, Cesar; Drake, Pilar; Pascual, Emilio
2006-01-01
Results of field surveys and laboratory measurements of oxygen consumption and body fluid osmolality at different salinities in the mysids Neomysis integer, Mesopodopsis slabberi, and Rhopalophthalmus mediterraneus from the Guadalquivir estuary (southwest Spain) were used to test the hypothesis that osmotic stress (oxygen consumption vs. isosmotic points) was lowest at salinities that field distributions suggest are optimal. The three species showed overlapping spatial distributions within the estuary but clear segregation along the salinity gradient: N. integer, M. slabberi, and R. mediterraneus displayed maximal densities at lower, intermediate, and higher salinities, respectively. Adults of N. integer were extremely efficient hyperregulators (isosmotic point 30 per thousand) over the full salinity range tested (3 per thousand-32 per thousand), and their oxygen consumption rates were independent of salinity; adults of M. slabberi were strong hyper- and hyporegulators at salinities between 7 per thousand and 29 per thousand (isosmotic point, 21 per thousand) and showed higher oxygen consumptions at the lowest salinity (6 per thousand); adults of R. mediterraneus hyperregulated at salinities between 19 per thousand and seawater (isosmotic point, 36 per thousand), with the lowest oxygen consumption at salinity around their isosmotic point (35 per thousand). Thus, the osmoregulation capabilities of M. slabberi and R. mediterraneus seem to determine the salinity ranges in which most of their adults live, but this is not so for adults of N. integer. Moreover, maximal field densities of M. slabberi (males and females) and R. mediterraneus (males) occur at the same salinities as the lowest oxygen consumption. In contrast, field distribution of N. integer was clearly biased toward the lower end of the salinity ranges within which it osmoregulated. We hypothesize that the greater euryhalinity of N. integer makes it possible for this species to avoid competition with R
NASA Astrophysics Data System (ADS)
Xu, Fei
In this article, we present a systematic approach to design chaos generators using integer order and fractional order differential equation systems. A series of multiwing chaotic attractors and grid multiwing chaotic attractors are obtained using linear integer order differential equation systems with switching controls. The existence of chaotic attractors in the corresponding fractional order differential equation systems is also investigated. We show that, using the nonlinear fractional order differential equation system, or linear fractional order differential equation systems with switching controls, a series of multiwing chaotic attractors can be obtained.
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).
Flury, Sabine; Gessner, Mark O.
2011-01-01
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. PMID:21148695
Suberkropp, K.; Gessner, M. O.; Chauvet, E.
1993-01-01
ATP and ergosterol were compared as indicators of fungal biomass associated with leaves decomposing in laboratory microcosms and streams. In all studies, the sporulation rates of the fungi colonizing leaves were also determined to compare patterns of fungal reproductive activity with patterns of mycelial growth. During leaf degradation, ATP concentrations exhibited significant, positive correlations with ergosterol concentrations in the laboratory and when leaves had been air dried prior to being submerged in a stream. However, when freshly shed leaves were submerged in a stream, concentrations of ATP and ergosterol were negatively correlated during degradation. This appeared to be due to the persistence of leaf-derived ATP in freshly shed leaves during the first 1 to 2 weeks in the stream. Estimates of fungal biomass from ergosterol concentrations of leaf litter were one to three times those calculated from ATP concentrations. ATP, ergosterol, and sporulation data generally provided similar information about the fungi associated with decomposing leaves in streams during periods when fungi were growing. Ergosterol concentrations provide a more accurate indication of fungal biomass in situations in which other organisms make significant contributions to ATP pools. PMID:16349069
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.
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.
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.
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.
Decomposed fuzzy systems and their application in direct adaptive fuzzy control.
Hsueh, Yao-Chu; Su, Shun-Feng; Chen, Ming-Chang
2014-10-01
In this paper, a novel fuzzy structure termed as the decomposed fuzzy system (DFS) is proposed to act as the fuzzy approximator for adaptive fuzzy control systems. The proposed structure is to decompose each fuzzy variable into layers of fuzzy systems, and each layer is to characterize one traditional fuzzy set. Similar to forming fuzzy rules in traditional fuzzy systems, layers from different variables form the so-called component fuzzy systems. DFS is proposed to provide more adjustable parameters to facilitate possible adaptation in fuzzy rules, but without introducing a learning burden. It is because those component fuzzy systems are independent so that it can facilitate minimum distribution learning effects among component fuzzy systems. It can be seen from our experiments that even when the rule number increases, the learning time in terms of cycles is still almost constant. It can also be found that the function approximation capability and learning efficiency of the DFS are much better than that of the traditional fuzzy systems when employed in adaptive fuzzy control systems. Besides, in order to further reduce the computational burden, a simplified DFS is proposed in this paper to satisfy possible real time constraints required in many applications. From our simulation results, it can be seen that the simplified DFS can perform fairly with a more concise decomposition structure.
Increasing litter species richness reduces variability in a terrestrial decomposer system.
Keith, Aidan M; Van der Wal, René; Brooker, Rob W; Osler, Graham H R; Chapman, Stephen J; Burslem, David F R P; Elston, David A
2008-09-01
Debate on the relationship between diversity and stability has been driven by the recognition that species loss may influence ecosystem properties and processes. We conducted a litterbag experiment in the Scottish Highlands, United Kingdom, to examine the effects of altering plant litter diversity on decomposition, microbial biomass, and microfaunal abundance. The design of treatments was fully factorial and included five species from an upland plant community (silver birch, Betula pendula; Scots' pine, Pinus sylvestris; heather, Calluna vulgaris; bilberry, Vaccinium myrtillus; wavy-hair grass, Deschampsia flexuosa); species richness ranged from one to five species. We tested the effects of litter species richness and composition on variable means, whether increasing litter species richness reduced variability in the decomposer system, and whether any richness-variability relationships were maintained over time (196 vs. 564 days). While litter species composition effects controlled variable means, we revealed reductions in variability with increasing litter species richness, even after accounting for differences between litter types. These findings suggest that higher plant species richness per se may result in more stable ecosystem processes (e.g., decomposition) and decomposer communities. Negative richness-variation relationships generally relaxed over time, presumably because properties of litter mixtures became more homogeneous. However, given that plant litter inputs continue to enter the belowground system over time, we conclude that variation in ecosystem properties may be buffered by greater litter species richness.
Tlili, Ahmed; Jabiol, Jérémy; Behra, Renata; Gil-Allué, Carmen; Gessner, Mark O
2017-02-21
With the accelerated use of silver nanoparticles (AgNP) in commercial products, streams will increasingly serve as recipients of, and repositories for, AgNP. This raises concerns about the potential toxicity of these nanomaterials in the environment. Here we aimed to assess the impacts of chronic AgNP exposure on the metabolic activities and community structure of fungal and bacterial plant litter decomposers as central players in stream ecosystems. Minimal variation in the size and surface charge of AgNP indicated that nanoparticles were rather stable during the experiment. Five days of exposure to 0.05 and 0.5 μM AgNP in microcosms shifted bacterial community structure but had no effect on a suite of microbial metabolic activities, despite silver accumulation in the decomposing leaf litter. After 25 days, however, a broad range of microbial endpoints, as well as rates of litter decomposition, were strongly affected. Declines matched with the total silver concentration in the leaves and were accompanied by changes in fungal and bacterial community structure. These results highlight a distinct sensitivity of litter-associated microbial communities in streams to chronic AgNP exposure, with effects on both microbial functions and community structure resulting in notable ecosystem consequences through impacts on litter decomposition and further biogeochemical processes.
Northward range extension of an endemic soil decomposer with a distinct trophic position.
Melody, Carol; Schmidt, Olaf
2012-12-23
Ecological niche theory asserts that invading species become established only if introduced propagules survive stochastic mortality and can exploit resources unconsumed by resident species. Because their transportation is not controlled by plant health or biosecurity regulations, soil macrofauna decomposers, including earthworms are probably introduced frequently into non-native soils. Yet even with climatic change, exotic earthworm species from southern Europe have not been reported to become established in previously glaciated areas of northern Europe that already have trophically differentiated earthworm communities of 'peregrine' species. We discovered established populations of the earthworm Prosellodrilus amplisetosus (Lumbricidae), a member of a genus endemic to southern France, in six habitats of an urban farm in Dublin, Ireland, about 1000 km north of the genus's endemic range. Not only was P. amplisetosus the dominant endogeic (geophagous) earthworm species in two habitats, it also occupied a significantly different trophic position from the resident species, as evinced by stable isotope ratio analysis. The suggested ability of this non-native species to feed on and assimilate isotopically more enriched soil carbon (C) and nitrogen fractions that are inaccessible to resident species portends potential implications of decomposer range expansions for soil functioning including C sequestration.
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.
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.
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.
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.
An Efficient Exact Quantum Algorithm for the Integer Square-free Decomposition Problem.
Li, Jun; Peng, Xinhua; Du, Jiangfeng; Suter, Dieter
2012-01-01
Quantum computers are known to be qualitatively more powerful than classical computers, but so far only a small number of different algorithms have been discovered that actually use this potential. It would therefore be highly desirable to develop other types of quantum algorithms that widen the range of possible applications. Here we propose an efficient and exact quantum algorithm for finding the square-free part of a large integer - a problem for which no efficient classical algorithm exists. The algorithm relies on properties of Gauss sums and uses the quantum Fourier transform. We give an explicit quantum network for the algorithm. Our algorithm introduces new concepts and methods that have not been used in quantum information processing so far and may be applicable to a wider class of problems.
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.
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.
A Class of Integer Order and Fractional Order Hyperchaotic Systems via the Chen System
NASA Astrophysics Data System (ADS)
Xu, Fei
2016-06-01
In this article, we investigate the generation of a class of hyperchaotic systems via the Chen chaotic system using both integer order and fractional order differential equation systems. Based on the Chen chaotic system, we designed a system with four nonlinear ordinary differential equations. For different parameter sets, the trajectory of the system may diverge or display a hyperchaotic attractor with double wings. By linearizing the ordinary differential equation system with divergent trajectory and designing proper switching controls, we obtain a chaotic attractor. Similar phenomenon has also been observed in linearizing the hyperchaotic system. The corresponding fractional order systems are also considered. Our investigation indicates that, switching control can be applied to either linearized chaotic or nonchaotic differential equation systems to create chaotic attractor.
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.
Optimization and implementation of the integer wavelet transform for image coding.
Grangetto, Marco; Magli, Enrico; Martina, Maurizio; Olmo, Gabriella
2002-01-01
This paper deals with the design and implementation of an image transform coding algorithm based on the integer wavelet transform (IWT). First of all, criteria are proposed for the selection of optimal factorizations of the wavelet filter polyphase matrix to be employed within the lifting scheme. The obtained results lead to the IWT implementations with very satisfactory lossless and lossy compression performance. Then, the effects of finite precision representation of the lifting coefficients on the compression performance are analyzed, showing that, in most cases, a very small number of bits can be employed for the mantissa keeping the performance degradation very limited. Stemming from these results, a VLSI architecture is proposed for the IWT implementation, capable of achieving very high frame rates with moderate gate complexity.
Double stop-band structure near half-integer tunes in high-intensity rings
NASA Astrophysics Data System (ADS)
Moriya, K.; Ota, M.; Fukushima, K.; Yamaguchi, M.; Ito, K.; Okamoto, H.
2016-11-01
This paper addresses a detailed experimental study of collective instability bands generated near every half-integer tune per lattice period by coherent dipole and quadrupole resonances. Both instabilities appear side by side or overlap each other but are mostly separable because the dipole resonance often creates a narrower stop band accompanied by more severe particle losses. The separation of these low-order resonance bands becomes greater as the beam intensity increases. In principle, the double stop-band structure can be formed even without machine imperfections when the beam's initial phase-space profile is deviated from the ideal stationary distribution. The tabletop ion-trap system called "S-POD" is employed to experimentally demonstrate the parameter dependence of the double stop-band structure. Numerical simulations are also performed for comparison with experimental observations.
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.
Energy Gaps and Layer Polarization of Integer and Fractional Quantum Hall States in Bilayer Graphene
NASA Astrophysics Data System (ADS)
Shi, Yanmeng; Lee, Yongjin; Che, Shi; Pi, Ziqi; Espiritu, Timothy; Stepanov, Petr; Smirnov, Dmitry; Lau, Chun Ning; Zhang, Fan
2016-02-01
Owing to the spin, valley, and orbital symmetries, the lowest Landau level in bilayer graphene exhibits multicomponent quantum Hall ferromagnetism. Using transport spectroscopy, we investigate the energy gaps of integer and fractional quantum Hall (QH) states in bilayer graphene with controlled layer polarization. The state at filling factor ν =1 has two distinct phases: a layer polarized state that has a larger energy gap and is stabilized by high electric field, and a hitherto unobserved interlayer coherent state with a smaller gap that is stabilized by large magnetic field. In contrast, the ν =2 /3 quantum Hall state and a feature at ν =1 /2 are only resolved at finite electric field and large magnetic field. These results underscore the importance of controlling layer polarization in understanding the competing symmetries in the unusual QH system of BLG.
Integer ambiguity resolution of the GPS carrier for spacecraft attitude determination
NASA Astrophysics Data System (ADS)
Cohen, Clark E.; Parkinson, Bradford W.
A novel technique for resolving integer ambiguity of the GPS carrier for spacecraft attitude determination is presented. The technique solves for both attitude and attitude rate, making use of both translational and rotational spacecraft motion. On the basis of experimental ground testing, the results indicate that this technique will rapidly arrive at reliable solutions. Results are achieved exclusively with GPS; no external aiding for any other sensor is employed. It is shown that the mathematics of attitude determination using GPS can be rephrased in the familiar form of attitude determination using vector observations. As a result, efficient techniques already applied to attitude determination using vector observations can be applied to attitude determination using GPS.
Adiabatic sweep cross-polarization magic-angle-spinning NMR of half-integer quadrupolar spins
NASA Astrophysics Data System (ADS)
Wi, Sungsool; Kim, Chul; Schurko, Robert; Frydman, Lucio
2017-04-01
The use of frequency-swept radiofrequency (rf) pulses for enhancing signals in the magic-angle spinning (MAS) spectra of half-integer quadrupolar nuclides was explored. The broadband adiabatic inversion cross-polarization magic-angle spinning (BRAIN-CPMAS) method, involving an adiabatic inversion pulse on the S-channel and a simultaneous rectangular spin-lock pulse on the I-channel (1H), was applied to I(1/2) → S(3/2) systems. Optimal BRAIN-CPMAS matching conditions were found to involve low rf pulse strengths for both the I- and S-spin channels. At these low and easily attainable rf field strengths, level-crossing events among the energy levels | 3 / 2 >, | 1 / 2 >, | - 1 / 2 >, | - 3 / 2 > that are known to complicate the CPMAS of quadrupolar nuclei, are mostly avoided. Zero- and double-quantum polarization transfer modes, akin to those we have observed for I(1/2) → S(1/2) polarization transfers, were evidenced by these analyses even in the presence of the quadrupolar interaction. 1H-23Na and 1H-11B BRAIN-CPMAS conditions were experimentally explored on model compounds by optimizing the width of the adiabatic sweep, as well as the rf pulse powers of the 1H and 23Na/11B channels, for different MAS rates. The experimental data obtained on model compounds containing spin-3/2 nuclides, matched well predictions from numerical simulations and from an average Hamiltonian theory model. Extensions to half-integer spin nuclides with higher spins and potential applications of this BRAIN-CPMAS approach are discussed.
Critical dense polymers with Robin boundary conditions, half-integer Kac labels and Z4 fermions
NASA Astrophysics Data System (ADS)
Pearce, Paul A.; Rasmussen, Jørgen; Tipunin, Ilya Yu.
2014-12-01
For general Temperley-Lieb loop models, including the logarithmic minimal models LM (p ,p‧) with p ,p‧ coprime integers, we construct an infinite family of Robin boundary conditions on the strip as linear combinations of Neumann and Dirichlet boundary conditions. These boundary conditions are Yang-Baxter integrable and allow loop segments to terminate on the boundary. Algebraically, the Robin boundary conditions are described by the one-boundary Temperley-Lieb algebra. Solvable critical dense polymers is the first member LM (1 , 2) of the family of logarithmic minimal models and has loop fugacity β = 0 and central charge c = - 2. Specialising to LM (1 , 2) with our Robin boundary conditions, we solve the model exactly on strips of arbitrary finite size N and extract the finite-size conformal corrections using an Euler-Maclaurin formula. The key to the solution is an inversion identity satisfied by the commuting double row transfer matrices. This inversion identity is established directly in the Temperley-Lieb algebra. We classify the eigenvalues of the double row transfer matrices using the physical combinatorics of the patterns of zeros in the complex spectral parameter plane and obtain finitised characters related to spaces of coinvariants of Z4 fermions. In the continuum scaling limit, the Robin boundary conditions are associated with irreducible Virasoro Verma modules with conformal weights Δ r , s -1/2 =1/32 (L2 - 4) where L = 2 s - 1 - 4 r, r ∈ Z, s ∈ N. These conformal weights populate a Kac table with half-integer Kac labels. Fusion of the corresponding modules with the generators of the Kac fusion algebra is examined and general fusion rules are proposed.
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.
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
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
Preservation and rapid purification of DNA from decomposing human tissue samples.
Sorensen, Amy; Rahman, Elizabeth; Canela, Cassandra; Gangitano, David; Hughes-Stamm, Sheree
2016-11-01
One of the key features to be considered in a mass disaster is victim identification. However, the recovery and identification of human remains are sometimes complicated by harsh environmental conditions, limited facilities, loss of electricity and lack of refrigeration. If human remains cannot be collected, stored, or identified immediately, bodies decompose and DNA degrades making genotyping more difficult and ultimately decreasing DNA profiling success. In order to prevent further DNA damage and degradation after collection, tissue preservatives may be used. The goal of this study was to evaluate three customized (modified TENT, DESS, LST) and two commercial DNA preservatives (RNAlater and DNAgard(®)) on fresh and decomposed human skin and muscle samples stored in hot (35°C) and humid (60-70% relative humidity) conditions for up to three months. Skin and muscle samples were harvested from the thigh of three human cadavers placed outdoors for up to two weeks. In addition, the possibility of purifying DNA directly from the preservative solutions ("free DNA") was investigated in order to eliminate lengthy tissue digestion processes and increase throughput. The efficiency of each preservative was evaluated based on the quantity of DNA recovered from both the "free DNA" in solution and the tissue sample itself in conjunction with the quality and completeness of downstream STR profiles. As expected, DNA quantity and STR success decreased with time of decomposition. However, a marked decrease in DNA quantity and STR quality was observed in all samples after the bodies entered the bloat stage (approximately six days of decomposition in this study). Similar amounts of DNA were retrieved from skin and muscle samples over time, but slightly more complete STR profiles were obtained from muscle tissue. Although higher amounts of DNA were recovered from tissue samples than from the surrounding preservative, the average number of reportable alleles from the "free DNA" was
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
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…
NASA Astrophysics Data System (ADS)
Mukherjee, Bijoy K.; Metia, Santanu
2009-10-01
The paper is divided into three parts. The first part gives a brief introduction to the overall paper, to fractional order PID (PIλDμ) controllers and to Genetic Algorithm (GA). In the second part, first it has been studied how the performance of an integer order PID controller deteriorates when implemented with lossy capacitors in its analog realization. Thereafter it has been shown that the lossy capacitors can be effectively modeled by fractional order terms. Then, a novel GA based method has been proposed to tune the controller parameters such that the original performance is retained even though realized with the same lossy capacitors. Simulation results have been presented to validate the usefulness of the method. Some Ziegler-Nichols type tuning rules for design of fractional order PID controllers have been proposed in the literature [11]. In the third part, a novel GA based method has been proposed which shows how equivalent integer order PID controllers can be obtained which will give performance level similar to those of the fractional order PID controllers thereby removing the complexity involved in the implementation of the latter. It has been shown with extensive simulation results that the equivalent integer order PID controllers more or less retain the robustness and iso-damping properties of the original fractional order PID controllers. Simulation results also show that the equivalent integer order PID controllers are more robust than the normal Ziegler-Nichols tuned PID controllers.
Verslycke, Tim; De Wasch, Katia; De Brabander, Hubert F; Janssen, Colin R
2002-04-01
Testosterone metabolism by Neomysis integer (Crustacea; Mysidacea) was assessed to obtain initial data on its metabolic capacity. N. integer were exposed to both testosterone and [(14)C]testosterone. Identification of testosterone metabolites and endogenous steroids was performed using thin-layer chromatography and liquid chromatography with multiple mass spectrometry. Endogenous production of testosterone in mysids was detected for the first time. N. integer were exposed to testosterone and metabolized administered testosterone extensively. At least 11 polar testosterone metabolites (R(f,metabolite) < R(f,testosterone)), androstenedione, dihydrotestosterone, and testosterone were produced in vivo by N. integer. A sex-specific testosterone metabolism was also observed, although this observation requires further confirmation. The anabolic steroid beta-boldenone was also identified for the first time in invertebrates. The metabolic pathway leading to the formation of beta-boldenone remains unknown, since the steroidal precursor androstadienedione could not be detected. These results reveal interesting similarities in enzyme systems in invertebrate and vertebrate species. Alterations in steroid hormone metabolism may be used as a new biomarker for the effects of endocrine disruptors in invertebrates.
NASA Astrophysics Data System (ADS)
Motrunich, Olexei; Geraedts, Scott
2013-03-01
We present a solvable boson model with U (1) × U (1) symmetry in (2+1) dimensions that realizes insulating phases with a quantized Hall conductivity σxy. The model is short-ranged, with no topological terms, and can be realized by a local Hamiltonian. For one set of parameters, the model has a non-fractionalized phase with σxy = 2 n in appropriate units, with n an integer. In this case, the physical origin is dynamical binding between n bosons of one species and a vortex of the other species and condensation of such composites. Other choices for the parameters of the model yield a phase with σxy = 2c/d , where c and d are mutually prime integers. In this phase, c bosons dynamically bind to d vortices and such objects condense. The are two species of excitations that are bosonic by themselves but carry fractional charge 1 / d and have mutual statistics 2 πb/d , where b is an integer such that ad - bc = 1 , and a is also an integer. The model can be studied using sign-free Monte Carlo. We have performed simulations which include a boundary between a quantum Hall insulator and a trivial insulator, and found gapless edge states on the boundary.
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
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
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…
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.
Synthesis of Graphene-Based Sensors and Application on Detecting SF6 Decomposing Products: A Review.
Zhang, Xiaoxing; Cui, Hao; Gui, Yingang
2017-02-13
Graphene-based materials have aroused enormous focus on a wide range of engineering fields because of their unique structure. One of the most promising applications is gas adsorption and sensing. In electrical engineering, graphene-based sensors are also employed as detecting devices to estimate the operation status of gas insulated switchgear (GIS). This paper reviews the main synthesis methods of graphene, gas adsorption, and sensing mechanism of its based sensors, as well as their applications in detecting SF6 decomposing products, such as SO2, H2S, SO2F2, and SOF2, in GIS. Both theoretical and experimental researches on gas response of graphene-based sensors to these typical gases are summarized. Finally, the future research trend about graphene synthesis technique and relevant perspective are also given.
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
Molecular identification of fungi found on decomposed human bodies in forensic autopsy cases.
Schwarz, Patrick; Dannaoui, Eric; Gehl, Axel; Felske-Zech, Heike; Birngruber, Christoph G; Dettmeyer, Reinhard B; Verhoff, Marcel A
2015-07-01
To investigate which fungi can be found during forensic autopsies, a PubMed literature review was done in regard to fungal growth on decomposed human bodies. Unfortunately, the existing data is limited and not all fungi were identified to the species level. We, therefore, collected skin samples with macroscopically visible fungal growth from 23 autopsy cases in Germany and identified the fungi to the species level by molecular methods. The identified species included Aspergillus fumigatus and Candida albicans, which pose an allergenic risk, especially to persons with underlying lung diseases. Because safety standards are lacking, we recommend the use of respiratory protection during exhumations and forensic autopsies, when fungal growth is noted. With regard to the future, a database was set up which could possibly be used as a forensic tool to determine the time of death.
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.
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.
Decomposing the causes of inequalities in health care use: a micro-simulations approach.
Huber, Hélène
2008-12-01
We propose an innovative method for the decomposition of factors associated with inequalities in the use of health care. We analyze individual data and make use of micro-simulations to evaluate the effect of heterogeneity of individual behaviors on inequality in access to care. Our study employs methods that, unlike earlier work, permits evaluation of heterogeneity of individual behaviors. We provide an application of this method by decomposing inequality of health care use in France in 1998. We show that half of the inequity in access to care is due to the heterogeneity of behaviors relative to the rank of individuals in the income distribution. This approach reconciles Oaxaca-like decompositions of inequality, focused on outcome gaps, with analyses involving decompositions of inequality by factors, focused on inequity indices.
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.
Tatsios, Giorgos; Stefanov, Stefan K; Valougeorgis, Dimitris
2015-06-01
The well-known Knudsen paradox observed in pressure driven rarefied gas flows through long capillaries is quantitatively explored by decomposing the particle distribution function into its ballistic and collision parts. The classical channel, tube, and duct Poiseuille flows are considered. The solution is obtained by a typical direct simulation Monte Carlo algorithm supplemented by a suitable particle decomposition indexation process. It is computationally confirmed that in the free-molecular and early transition regimes the reduction rate of the ballistic flow is larger than the increase rate of the collision flow deducing the Knudsen minimum of the overall flow. This description interprets in a precise, quantitative manner the appearance of the Knudsen minimum and verifies previously reported qualitative physical arguments.
NASA Astrophysics Data System (ADS)
Tatsios, Giorgos; Stefanov, Stefan K.; Valougeorgis, Dimitris
2015-06-01
The well-known Knudsen paradox observed in pressure driven rarefied gas flows through long capillaries is quantitatively explored by decomposing the particle distribution function into its ballistic and collision parts. The classical channel, tube, and duct Poiseuille flows are considered. The solution is obtained by a typical direct simulation Monte Carlo algorithm supplemented by a suitable particle decomposition indexation process. It is computationally confirmed that in the free-molecular and early transition regimes the reduction rate of the ballistic flow is larger than the increase rate of the collision flow deducing the Knudsen minimum of the overall flow. This description interprets in a precise, quantitative manner the appearance of the Knudsen minimum and verifies previously reported qualitative physical arguments.
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.
Gredebäck, Gustaf; Daum, Moritz M
2015-06-01
In this article, we review recent evidence of infants' early competence in perceiving and interpreting the actions of others. We present a theoretical model that decomposes the timeline of action perception into a series of distinct processes that occur in a particular order. Once an agent is detected, covert attention can be allocated to the future state of the agent (priming), which may lead to overt gaze shifts that predict goals (prediction). Once these goals are achieved, the consequence of the agents' actions and the manner in which the actions were performed can be evaluated (evaluation). We propose that all of these processes have unique requirements, both in terms of timing and cognitive resources. To understand more fully the rich social world of infants, we need to pay more attention to the temporal structure of social perception and ask what information is available to infants and how this changes over time.
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)
Synthesis of Graphene-Based Sensors and Application on Detecting SF6 Decomposing Products: A Review
Zhang, Xiaoxing; Cui, Hao; Gui, Yingang
2017-01-01
Graphene-based materials have aroused enormous focus on a wide range of engineering fields because of their unique structure. One of the most promising applications is gas adsorption and sensing. In electrical engineering, graphene-based sensors are also employed as detecting devices to estimate the operation status of gas insulated switchgear (GIS). This paper reviews the main synthesis methods of graphene, gas adsorption, and sensing mechanism of its based sensors, as well as their applications in detecting SF6 decomposing products, such as SO2, H2S, SO2F2, and SOF2, in GIS. Both theoretical and experimental researches on gas response of graphene-based sensors to these typical gases are summarized. Finally, the future research trend about graphene synthesis technique and relevant perspective are also given. PMID:28208836
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
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
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.
Fernandes, Isabel; Duarte, Sofia; Cássio, Fernanda; Pascoal, Cláudia
2013-11-01
We examined the potential long-term impacts of riparian plant diversity loss on diversity and activity of aquatic microbial decomposers. Microbial assemblages were obtained in a mixed-forest stream by immersion of mesh bags containing three leaf species (alder, oak and eucalyptus), commonly found in riparian corridors of Iberian streams. Simulation of species loss was done in microcosms by including a set of all leaf species, retrieved from the stream, and non-colonized leaves of three, two or one leaf species. Leaves were renewed every month throughout six months, and microbial inoculum was ensured by a set of colonized leaves from the previous month. Microbial diversity, leaf mass loss and fungal biomass were assessed at the second and sixth months after plant species loss. Molecular diversity of fungi and bacteria, as the total number of operational taxonomic units per leaf diversity treatment, decreased with leaf diversity loss. Fungal biomass tended to decrease linearly with leaf species loss on oak and eucalyptus, suggesting more pronounced effects of leaf diversity on lower quality leaves. Decomposition of alder and eucalyptus leaves was affected by leaf species identity, mainly after longer times following diversity loss. Leaf decomposition of alder decreased when mixed with eucalyptus, while decomposition of eucalyptus decreased in mixtures with oak. Results suggest that the effects of leaf diversity on microbial decomposers depended on leaf species number and also on which species were lost from the system, especially after longer times. This may have implications for the management of riparian forests to maintain stream ecosystem functioning.
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.
Antibiotics as a chemical stressor affecting an aquatic decomposer-detritivore system.
Bundschuh, Mirco; Hahn, Torsten; Gessner, Mark O; Schulz, Ralf
2009-01-01
Recent evidence indicates that a variety of antibiotic residues may affect the integrity of streams located downstream from wastewater treatment plants. Aquatic communities comprising bacterial and fungal decomposers and invertebrate detritivores (shredders) play an important role in the decomposition of allochthonous leaf litter, which acts as a primary energy source for small running waters. The aim of the present study was to assess whether an antibiotic mixture consisting of sulfamethoxazole, trimethoprim, erythromycin-H2O, roxithromycin, and clarithromycin has an effect on such a decomposer-detritivore system. Leaf discs were exposed to these antibiotics (total concentration of 2 or 200 microg/L) for approximately 20 d before offering these discs and corresponding control discs to an amphipod shredder, Gammarus fossarum, in a food choice experiment. Gammarus preferred the leaf discs conditioned in the presence of the antibiotic mixture at 200 microg/L over the control discs (pair-wise t test; p = 0.006). A similar tendency, while not significant, was observed for leaves conditioned with antibiotics at a concentration of 2 microg/L. The number of bacteria associated with leaves did not differ between treatments at either antibiotic concentration (t test; p = 0.57). In contrast, fungal biomass (measured as ergosterol) was significantly higher in the 200 microg/L treatment (t test; p = 0.038), suggesting that the preference of Gammarus may be related to a shift in fungal communities. Overall these results indicate that mixtures of antibiotics may disrupt important ecosystem processes such as organic matter flow in stream ecosystems, although effects are likely to be weak at antibiotic concentrations typical of streams receiving wastewater treatment plant effluents.
Vogt, Kristiina A; Edmonds, Robert L; Grier, Charles C
1981-08-01
Sporocarps and sclerotia were collected for a one-year period in 23- and 180-year-old Abies amabilis stands in western Washington. All sporocarps were classified and chemically analyzed for N, P, K, Ca, Mg, Na and Fe. Lactarius sp. and Cortinarius sp. contributed the largest proportion of the total annual epigeous sporocarp production in both stands. Annual epigeous production was 34 kg/ha in the young stand and 27 kg/ha in the mature stand. Hypogeous sporocarp production increased from 1 kg ha(-1) yr(-1) to 380 kg ha(-1) yr(-1) with increasing stand age. High sclerotia biomass occurred in the young (2,300 kg/ha) and mature (3,000 kg/ha) stands. Peak sclerotia and epigeous sporocarp biomass in the young stand and epigeous and hypogeous sporocarp biomass in the mature stand coincided with the fall peak of mycorrhizal root biomass.In the young stand, sporocarps produced by decomposer fungi concentrated higher levels of Ca and Mn than those produced by mycorrhizal fungi. In the mature stand, sporocarps of decomposer fungi concentrated higher levels of N, P, Mn, Ca and Fe than sporocarps of mycorrhizal fungi. Epigeous and hypogeous sporocarps concentrated higher levels of N, P, and K than sclerotia or mycelium. The highest concentration of N (4.36%), P (0.76%), K (3.22%) and Na (1,678 ppm) occurred in epigeous sporocarps. Highest Mn (740 ppm) and Ca (20,600 ppm) concentrations occurred in mycelium, while highest Mg (1,929 ppm) concentrations were in hypogeous sporocarps and highest Fe (4,153 ppm) concentrations were in sclerotia.
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
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.
NASA Astrophysics Data System (ADS)
Parsons, S. A.; Valdez-Ramirez, V.; Congdon, R. A.; Williams, S. E.
2014-09-01
The seasonality of litter inputs in forests has important implications for understanding ecosystem processes and biogeochemical cycles. We quantified the drivers of seasonality in litterfall and leaf decomposability using plots throughout the Australian wet tropical region. Litter fell mostly in the summer (wet, warm) months in the region, but other peaks occurred throughout the year. Litterfall seasonality was modelled well with the level of deciduousness of the site (plots with more deciduous species had lower seasonality than evergreen plots), temperature (higher seasonality in the uplands), disturbance (lower seasonality with more early secondary species) and soil fertility (higher seasonality with higher N : P/P limitation) (SL total litterfall model 1 = deciduousness + soil N : P + early secondary sp.: r2 = 0.63, n = 30; model 2 = temperature + early secondary sp. + soil N : P: r2 = 0.54, n = 30; SL leaf = temperature + early secondary sp. + rainfall seasonality: r2 = 0.39, n = 30). Leaf litter decomposability was lower in the dry season than in the wet season, driven by higher phenolic concentrations in the dry, with the difference exacerbated particularly by lower dry season moisture. Our results are contrary to the global trend for tropical rainforests; in that seasonality of litterfall input was generally higher in wetter, cooler, evergreen forests, compared to generally drier, warmer, semi-deciduous sites that had more uniform monthly inputs. We consider this due to more diverse litter shedding patterns in semi-deciduous and raingreen rainforest sites, and an important consideration for ecosystem modellers. Seasonal changes in litter quality are likely to have impacts on decomposition and biogeochemical cycles in these forests due to the litter that falls in the dry season being more recalcitrant to decay.
NASA Astrophysics Data System (ADS)
Parsons, S. A.; Valdez-Ramirez, V.; Congdon, R. A.; Williams, S. E.
2014-06-01
The seasonality of litter inputs in forests has important implications for understanding ecosystem processes and biogeochemical cycles. We quantified the drivers of seasonality in litterfall and leaf decomposability, using plots throughout the Australian wet tropical region. Litter fell mostly in the summer (wet, warm) months in the region, but other peaks occurred throughout the year. Litterfall seasonality was modelled well with the level of deciduousness of the site (plots with more deciduous species had lower seasonality than evergreen plots), temperature (higher seasonality in the uplands), disturbance (lower seasonality with more early secondary species) and soil fertility (higher seasonality with higher N : P/P limitation) (SL total litterfall model 1 = deciduousness + soil N : P + early secondary sp: r2 = 0.63, n = 30 plots; model 2 = temperature + early secondary sp. + soil N : P: r2 = 0.54, n = 30; SL leaf = temperature + early secondary sp. + rainfall seasonality: r2 = 0.39, n = 30). Leaf litter decomposability was lower in the dry season than in the wet season, driven by higher phenolic concentrations in the dry, with the difference exacerbated particularly by lower dry season moisture. Our results are contrary to the global trend for tropical rainforests; in that seasonality of litterfall inputs were generally higher in wetter, cooler, evergreen forests, compared to generally drier, warmer, semi-deciduous sites that had more uniform monthly inputs. We consider this due to more diverse litter shedding patterns in semi-deciduous and raingreen rainforest sites, and an important consideration for ecosystem modellers. Seasonal changes in litter quality are likely to have impacts on decomposition and biogeochemical cycles in these forests due to the litter that falls in the dry being more recalcitrant to decay.
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
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
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
A FORTRAN-Based Program for Computerized Algebraic Manipulation.
1982-09-21
storage will be required for intermediate and final results. When the size and length of the program approach the limit of a particular machine, storage...15,161. The latter approach is simpler and easier to implement and thus is the approach that is fol- lowed. PROGRAM OBJECTIVES The construction of a...bracket (1,J)m n with respect to the variables m,n. The result is stored in location K. Subroutine INTEG (IJ,K) INTEG (Ij,K) integrates each term of I with
Carbon transferred from living to decomposing in the late April 2011 tornado outbreak
NASA Astrophysics Data System (ADS)
Peterson, C. J.; Cannon, J. B.; Hepinstall-Cymerman, J.
2013-12-01
Rare but extreme climatic events are difficult to study but likely have major impacts on the carbon cycle when they occur. Recent research has begun to reveal the carbon footprint of major hurricanes, but the impact of other types of wind disturbances remains unexplored. The late April 2011 tornado outbreak across the Southeastern U.S. was one of the largest in history. We have conducted detailed analyses of one long-track (64 km) tornado across northern Georgia, whose damage track was almost entirely in forest. This tornado, rated an EF-3, damaged a total of 4492.8 ha out of 12,875 ha. Using a supervised classification of aerial imagery, we quantified the forest area that experienced different severities of wind damage; the great majority of the damage was light (54.6% of the tornado track lost < 20% of standing basal area), and only ~ 1% of the track experienced > 80% basal area loss. We subsequently estimated the carbon transferred from living to decomposing from this one tornado track to be 0.212 Tg. We scaled the proportion of forest area experiencing different severities of damage to the entire outbreak (310 tornado segments surveyed by NWS teams), and used Google Earth imagery to calculate the linear length of forest within all of the late April 2011 tornado tracks. The outbreak tornadoes created 2691 km of linear damage track through forest (total track length through all land use types was much greater). Forested path length was converted to forest area using estimates of damage path width from NWS damage surveys, yielding an estimated total forest damage area of 123,434 ha for the outbreak. Assuming a similar distribution of damage severities to that seen in the north GA tornado track, we estimated the total area impacted at different severities. Finally, the areas experiencing these severities were converted to biomass using US Forest Service FIA data on county-by-county standing forest biomass, and then converted to carbon. Summing across all 310
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.
2013-01-01
Background Recovering the network topology and associated kinetic parameter values from time-series data are central topics in systems biology. Nevertheless, methods that simultaneously do both are few and lack generality. Results Here, we present a rigorous approach for simultaneously estimating the parameters and regulatory topology of biochemical networks from time-series data. The parameter estimation task is formulated as a mixed-integer dynamic optimization problem with: (i) binary variables, used to model the existence of regulatory interactions and kinetic effects of metabolites in the network processes; and (ii) continuous variables, denoting metabolites concentrations and kinetic parameters values. The approach simultaneously optimizes the Akaike criterion, which captures the trade-off between complexity (measured by the number of parameters), and accuracy of the fitting. This simultaneous optimization mitigates a possible overfitting that could result from addition of spurious regulatory interactions. Conclusion The capabilities of our approach were tested in one benchmark problem. Our algorithm is able to identify a set of plausible network topologies with their associated parameters. PMID:24176044
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.
NASA Astrophysics Data System (ADS)
Singha, Aniket; Fauzi, M. H.; Hirayama, Y.; Muralidharan, Bhaskaran
2017-03-01
The interplay of spin-polarized electronic edge states with the dynamics of the host nuclei in quantum Hall systems presents rich and nontrivial transport physics. Here, we develop a Landauer-Büttiker approach to understand various experimental features observed in the integer quantum Hall setups featuring quantum point contacts. The approach developed here entails a phenomenological description of spin-resolved interedge scattering induced via hyperfine assisted electron-nuclear spin flip-flop processes. A self-consistent simulation framework between the nuclear spin dynamics and edge state electronic transport is presented in order to gain crucial insights into the dynamic nuclear polarization effects on electronic transport and in turn the electron-spin polarization effects on the nuclear spin dynamics. In particular, we show that the hysteresis noted experimentally in the conductance-voltage trace as well as in the resistively detected NMR line-shape results from a lack of quasiequilibrium between electronic transport and nuclear polarization evolution. In addition, we present circuit models to emulate such hyperfine mediated transport effects to further facilitate a clear understanding of the electronic transport processes occurring around the quantum point contact. Finally, we extend our model to account for the effects of quadrupolar splitting of nuclear levels and also depict the electronic transport signatures that arise from single and multiphoton processes.
Wang, Jing; Zhou, Quan; Lian, Biao; ...
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
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.
The integer quantum Hall effect of a square lattice with an array of point defects.
Islamoğlu, S; Oktel, M O; Gülseren, O
2012-08-29
The electronic properties of a square lattice under an applied perpendicular magnetic field in the presence of impurities or vacancies are investigated by the tight-binding method including up to second nearest neighbor interactions. These imperfections result in new gaps and bands in the Hofstadter butterfly even when the second order interactions break the bipartite symmetry. In addition, the whole spectrum of the Hall conduction is obtained by the Kubo formula for the corresponding cases. The results are in accordance with the Thouless-Kohmoto-Nightingale-den Nijs integers when the Fermi energy lies in an energy gap. We find that the states due to the vacancies or impurities with small hopping constants are highly localized and do not contribute to the Hall conduction. However, the impurities with high hopping constants result in new Hall plateaus with constant conduction of σ(xy) =± e(2)/h, since high hopping constants increase the probability of an electron contributing to the conduction.
New image compression algorithm based on improved reversible biorthogonal integer wavelet transform
NASA Astrophysics Data System (ADS)
Zhang, Libao; Yu, Xianchuan
2012-10-01
The low computational complexity and high coding efficiency are the most significant requirements for image compression and transmission. Reversible biorthogonal integer wavelet transform (RB-IWT) supports the low computational complexity by lifting scheme (LS) and allows both lossy and lossless decoding using a single bitstream. However, RB-IWT degrades the performances and peak signal noise ratio (PSNR) of the image coding for image compression. In this paper, a new IWT-based compression scheme based on optimal RB-IWT and improved SPECK is presented. In this new algorithm, the scaling parameter of each subband is chosen for optimizing the transform coefficient. During coding, all image coefficients are encoding using simple, efficient quadtree partitioning method. This scheme is similar to the SPECK, but the new method uses a single quadtree partitioning instead of set partitioning and octave band partitioning of original SPECK, which reduces the coding complexity. Experiment results show that the new algorithm not only obtains low computational complexity, but also provides the peak signal-noise ratio (PSNR) performance of lossy coding to be comparable to the SPIHT algorithm using RB-IWT filters, and better than the SPECK algorithm. Additionally, the new algorithm supports both efficiently lossy and lossless compression using a single bitstream. This presented algorithm is valuable for future remote sensing image compression.
Reversible n-Bit to n-Bit Integer Haar-Like Transforms
Senecal, J; Duchaineau, M; Joy, K I
2003-11-03
We introduce a wavelet-like transform similar to the Haar transform, but with the properties that it packs the results into the same number of bits as the original data, and is reversible. Our method, called TLHaar, uses table lookups to replace the averaging, differencing, and bit shifting performed in a Haar IntegerWavelet Transform (IWT). TLHaar maintains the same coefficient magnitude relationships for the low- and high-pass coefficients as true Haar, but reorders them to fit into the same number of bits as the input signal, thus eliminating the sign bit that is added to the Haar IWT output coefficients. Eliminating the sign bit avoids using extra memory and speeds the transform process. We tested TLHaar on a variety of image types, and when compared to the Haar IWT TLHaar is significantly faster. For image data with lines or hard edges TLHaar coefficients compress better than those of the Haar IWT. Due to its speed TLHaar is suitable for streaming hardware implementations with fixed data sizes, such as DVI channels.
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.
Alternative mathematical programming formulations for FSS synthesis
NASA Technical Reports Server (NTRS)
Reilly, C. H.; Mount-Campbell, C. A.; Gonsalvez, D. J. A.; Levis, C. A.
1986-01-01
A variety of mathematical programming models and two solution strategies are suggested for the problem of allocating orbital positions to (synthesizing) satellites in the Fixed Satellite Service. Mixed integer programming and almost linear programming formulations are presented in detail for each of two objectives: (1) positioning satellites as closely as possible to specified desired locations, and (2) minimizing the total length of the geostationary arc allocated to the satellites whose positions are to be determined. Computational results for mixed integer and almost linear programming models, with the objective of positioning satellites as closely as possible to their desired locations, are reported for three six-administration test problems and a thirteen-administration test problem.
Low cost high throughput pipelined architecture of 2-D 8 × 8 integer transforms for H.264/AVC
NASA Astrophysics Data System (ADS)
Sharma, Meeturani; Durga Tiwari, Honey; Cho, Yong Beom
2013-08-01
In this article, we present the implementation of high throughput two-dimensional (2-D) 8 × 8 forward and inverse integer DCT transform for H.264. Using matrix decomposition and matrix operation, such as the Kronecker product and direct sum, the forward and inverse integer transform can be represented using simple addition operations. The dual clocked pipelined structure of the proposed implementation uses non-floating point adders and does not require any transpose memory. Hardware synthesis shows that the maximum operating frequency of the proposed pipelined architecture is 1.31 GHz, which achieves 21.05 Gpixels/s throughput rate with the hardware cost of 42932 gates. High throughput and low hardware makes the proposed design useful for real time H.264/AVC high definition processing.
Garcia-Gracia, Hipolito; Gutiérrez-Vega, Julio C
2009-04-01
A detailed analysis of the plane-wave diffraction by a finite-radius circular spiral phase plate (SPP) with integer and fractional topological charge and with variable transmission coefficients inside and outside of the plate edge is presented. We characterize the effect of varying the transmission coefficients and the parameters of the SPP on the propagated field. The vortex structure for integer and fractional phase step of the SPPs with and without phase apodization at the plate edge is also analyzed. The consideration of the interference between the light crossing the SPP and the light that undergoes no phase alteration at the aperture plane reveals new and interesting phenomena associated to this classical problem.
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.
Cheung, Vincent C K; Devarajan, Karthik; Severini, Giacomo; Turolla, Andrea; Bonato, Paolo
2015-08-01
The non-negative matrix factorization algorithm (NMF) decomposes a data matrix into a set of non-negative basis vectors, each scaled by a coefficient. In its original formulation, the NMF assumes the data samples and dimensions to be independently distributed, making it a less-than-ideal algorithm for the analysis of time series data with temporal correlations. Here, we seek to derive an NMF that accounts for temporal dependencies in the data by explicitly incorporating a very simple temporal constraint for the coefficients into the NMF update rules. We applied the modified algorithm to 2 multi-dimensional electromyographic data sets collected from the human upper-limb to identify muscle synergies. We found that because it reduced the number of free parameters in the model, our modified NMF made it possible to use the Akaike Information Criterion to objectively identify a model order (i.e., the number of muscle synergies composing the data) that is more functionally interpretable, and closer to the numbers previously determined using ad hoc measures.
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 decomposable silica-based antibacterial coating for percutaneous titanium implant.
Wang, Jia; Wu, Guofeng; Liu, Xiangwei; Sun, Guanyang; Li, Dehua; Wei, Hongbo
2017-01-01
Although percutaneous titanium implants have become one of the best choices as retainers in the facial defects, peri-implantitis still occurs at a significant rate. This unwanted complication occurs due to adhesion of bacteria and subsequent biofilm formation. To solve this problem, we have developed a novel antibiotic nanodelivery system based on self-decomposable silica nanoparticles. In this study, silica-gentamycin (SG) nanoparticles were successfully fabricated using an innovative one-pot solution. The nanoparticles were incorporated within a gelatin matrix and cross-linked on microarc-oxidized titanium. To characterize the SG nanoparticles, their particle size, zeta potential, surface morphology, in vitro drug release, and decomposition process were sequentially evaluated. The antibacterial properties against the gram-positive Staphylococcus aureus, including bacterial viability, antibacterial rate, and bacteria morphology, were analyzed using SG-loaded titanium specimens. Any possible influence of released gentamycin on the viability of human fibroblasts, which are the main component of soft tissues, was investigated. SG nanoparticles from the antibacterial titanium coating continuously released gentamycin and inhibited S. aureus growth. In vitro investigation showed that the obtained nanodelivery system has good biocompatibility. Therefore, this design can be further investigated as a method to prevent infection around percutaneous implants.
Miao, Wenjun; Kim, Hyungjun; Gujrati, Vipul; Kim, Jin Yong; Jon, Hyeongsu; Lee, Yonghyun; Choi, Minsuk; Kim, Jinjoo; Lee, Soyoung; Lee, Dong Yun; Kang, Sukmo; Jon, Sangyong
2016-01-01
Combination of photodynamic therapy (PDT) with photothermal therapy (PTT) has achieved significantly improved therapeutic efficacy compared to a single phototherapy modality. However, most nanomaterials used for combined PDT/PTT are made of non-biodegradable materials (e.g., gold nanorods, carbon nanotubes, and graphenes) and may remain intact in the body for long time, raising concerns over their potential long-term toxicity. Here we report a new combined PDT/PTT nanomedicine, designated SP3NPs, that exhibit photo-decomposable, photodynamic and photothermal properties. SP3NPs were prepared by self-assembly of PEGylated cypate, comprising FDA-approved PEG and an ICG derivative. We confirmed the ability of SP3NPs to generate both singlet oxygen for a photodynamic effect and heat for photothermal therapy in response to NIR laser irradiation in vitro. Also, the unique ability of SP3NPs to undergo irreversible decomposition upon NIR laser irradiation was demonstrated. Further our experimental results demonstrated that SP3NPs strongly accumulated in tumor tissue owing to their highly PEGylated surface and relatively small size (~60 nm), offering subsequent imaging-guided combined PDT/PTT treatment that resulted in tumor eradication and prolonged survival of mice. Taken together, our SP3NPs described here may represent a novel and facile approach for next-generation theranostics with great promise for translation into clinical practice in the future. PMID:27877241
Cellulose utilization in forest litter and soil: identification of bacterial and fungal decomposers.
Stursová, Martina; Zifčáková, Lucia; Leigh, Mary Beth; Burgess, Robert; Baldrian, Petr
2012-06-01
Organic matter decomposition in the globally widespread coniferous forests has an important role in the carbon cycle, and cellulose decomposition is especially important in this respect because cellulose is the most abundant polysaccharide in plant litter. Cellulose decomposition was 10 times faster in the fungi-dominated litter of Picea abies forest than in the bacteria-dominated soil. In the soil, the added (13)C-labelled cellulose was the main source of microbial respiration and was preferentially accumulated in the fungal biomass and cellulose induced fungal proliferation. In contrast, in the litter, bacterial biomass showed higher labelling after (13)C-cellulose addition and bacterial biomass increased. While 80% of the total community was represented by 104-106 bacterial and 33-59 fungal operational taxonomic units (OTUs), 80% of the cellulolytic communities of bacteria and fungi were only composed of 8-18 highly abundant OTUs. Both the total and (13)C-labelled communities differed substantially between the litter and soil. Cellulolytic bacteria in the acidic topsoil included Betaproteobacteria, Bacteroidetes and Acidobacteria, whereas these typically found in neutral soils were absent. Most fungal cellulose decomposers belonged to Ascomycota; cellulolytic Basidiomycota were mainly represented by the yeasts Trichosporon and Cryptococcus. Several bacteria and fungi demonstrated here to derive their carbon from cellulose were previously not recognized as cellulolytic.
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.
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.
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.
Decomposer animal communities in forest soil along heavy metal pollution gradient.
Haimi, J; Siira-Pietikäinen, A
1996-03-01
Responses of soil decomposer animals to heavy metal contamination and to concomitant changes in organic matter quality and quantity and in soil microbial biomasses have been studied along a pollution gradient from a Cu-Ni smelter. Samples have been taken separately for nematodes, enchytraeids and microarthropods 0.5, 2 and 8 km from the smelter. Special attention has been paid to the changes in the collembolan fauna. The sampling sites have been located in homogeneous Scots pine ( Pinus sylvestris) forests with podsolic soil profiles. In addition, an experiment has been carried out in which intact soil cores have been transferred in mesh baskets between the sites 2 and 8 km from the smelter (control samples have been transferred within the sites). Although most soil animals seemed to be quite resistant to direct and indirect effects of heavy metals, results indicate that certain soil animals like enchytraeids can be useful and easy to monitor when the effects of heavy metals on soil decomposition systems are assessed.
A'Bear, A Donald; Murray, William; Webb, Rachel; Boddy, Lynne; Jones, T Hefin
2013-01-01
Predicting the influence of biotic and abiotic factors on species interactions and ecosystem processes is among the primary aims of community ecologists. The composition of saprotrophic fungal communities is a consequence of competitive mycelial interactions, and a major determinant of woodland decomposition and nutrient cycling rates. Elevation of atmospheric temperature is predicted to drive changes in fungal community development. Top-down regulation of mycelial growth is an important determinant of, and moderator of temperature-driven changes to, two-species interaction outcomes. This study explores the interactive effects of a 4 °C temperature increase and soil invertebrate (collembola or woodlice) grazing on multispecies interactions between cord-forming basidiomycete fungi emerging from colonised beech (Fagus sylvatica) wood blocks. The fungal dominance hierarchy at ambient temperature (16 °C; Phanerochaete velutina > Resinicium bicolor > Hypholoma fasciculare) was altered by elevated temperature (20 °C; R. bicolor > P. velutina > H. fasciculare) in ungrazed systems. Warming promoted the competitive ability of the fungal species (R. bicolor) that was preferentially grazed by all invertebrate species. As a consequence, grazing prevented the effect of temperature on fungal community development and maintained a multispecies assemblage. Decomposition of fungal-colonised wood was stimulated by warming, with implications for increased CO2 efflux from woodland soil. Analogous to aboveground plant communities, increasing complexity of biotic and abiotic interactions appears to be important in buffering climate change effects on soil decomposers.
Oulehle, F; Cosby, B J; Wright, R F; Hruška, J; Kopáček, J; Krám, P; Evans, C D; Moldan, F
2012-06-01
We present a new formulation of the acidification model MAGIC that uses decomposer dynamics to link nitrogen (N) cycling to carbon (C) turnover in soils. The new model is evaluated by application to 15-30 years of water chemistry data at three coniferous-forested sites in the Czech Republic where deposition of sulphur (S) and N have decreased by >80% and 40%, respectively. Sulphate concentrations in waters have declined commensurately with S deposition, but nitrate concentrations have shown much larger decreases relative to N deposition. This behaviour is inconsistent with most conceptual models of N saturation, and with earlier versions of MAGIC which assume N retention to be a first-order function of N deposition and/or controlled by the soil C/N ratio. In comparison with earlier versions, the new formulation more correctly simulates observed short-term changes in nitrate leaching, as well as long-term retention of N in soils. The model suggests that, despite recent deposition reductions and recovery, progressive N saturation will lead to increased future nitrate leaching, ecosystem eutrophication and re-acidification.
Salminen, J; Liiri, M; Haimi, J
2002-09-01
Soil respiration from microcosms contaminated with pentachlorophenol, 2-ethanolhexanoate, creosote, CuSO4, and benomyl was measured in order to evaluate usefulness of soil microcosms and microbial respiration rate monitoring as a toxicity test in soils with high organic matter content. Coniferous forest soil and its organisms were used as test objects. In addition, how a short-term low temperature period including frost affects respiration dynamics in stressed soils was studied, i.e., whether contaminants reduce resistance of the community to other (also natural) stresses. In addition, at the end of the experiment, effects of contaminants on faunal and microbial community structures were analyzed. Soil respiration measurements from the microcosms appeared to be a sensitive parameter for testing community-level effects of chemicals in the soil with high organic matter content. An 84-day exposure had acute effects, long-term effects, delaying effects, and total recovery of community respiration. Direct negative and indirect positive effects of chemical contamination on the community of soil organisms were found. Responses to contamination of soil respiration rate and structure of the soil community were parallel. Addition of pentachlorophenol, 2-ethanolhexane, and Cu into the soil reduced frost resistance of the decomposer community. It was concluded that soil respiration monitoring of artificially contaminated soil microcosms seems to be a useful tool for testing community-level toxic effects of chemicals.
A decomposable silica-based antibacterial coating for percutaneous titanium implant
Wang, Jia; Wu, Guofeng; Liu, Xiangwei; Sun, Guanyang; Li, Dehua; Wei, Hongbo
2017-01-01
Although percutaneous titanium implants have become one of the best choices as retainers in the facial defects, peri-implantitis still occurs at a significant rate. This unwanted complication occurs due to adhesion of bacteria and subsequent biofilm formation. To solve this problem, we have developed a novel antibiotic nanodelivery system based on self-decomposable silica nanoparticles. In this study, silica-gentamycin (SG) nanoparticles were successfully fabricated using an innovative one-pot solution. The nanoparticles were incorporated within a gelatin matrix and cross-linked on microarc-oxidized titanium. To characterize the SG nanoparticles, their particle size, zeta potential, surface morphology, in vitro drug release, and decomposition process were sequentially evaluated. The antibacterial properties against the gram-positive Staphylococcus aureus, including bacterial viability, antibacterial rate, and bacteria morphology, were analyzed using SG-loaded titanium specimens. Any possible influence of released gentamycin on the viability of human fibroblasts, which are the main component of soft tissues, was investigated. SG nanoparticles from the antibacterial titanium coating continuously released gentamycin and inhibited S. aureus growth. In vitro investigation showed that the obtained nanodelivery system has good biocompatibility. Therefore, this design can be further investigated as a method to prevent infection around percutaneous implants. PMID:28123297
Double loaded self-decomposable SiO₂ nanoparticles for sustained drug release.
Zhao, Saisai; Zhang, Silu; Ma, Jiang; Fan, Li; Yin, Chun; Lin, Ge; Li, Quan
2015-10-21
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.