A Dynamic Programming Approach to Adaptive Fractionation
Ramakrishnan, Jagdish; Bortfeld, Thomas; Tsitsiklis, John
2011-01-01
We formulate a previously introduced adaptive fractionation problem in a dynamic programming (DP) framework and explore various solution techniques. The two messages of this paper are: (i) the DP model is a useful framework for studying adaptive radiation therapy, particularly adaptive fractionation, and (ii) there is a potential for substantial decrease in dose to the primary organ-at-risk (OAR), or equivalently increase in tumor escalation, when using an adaptive fraction size. The essence of adaptive fractionation is to increase the fraction size when observing a "favorable" anatomy or when the tumor and OAR are far apart and to decrease the fraction size when they are close together. Given that a fixed prescribed dose must be delivered to the tumor over the course of the treatment, such an approach results in a lower cumulative dose to the OAR when compared to that resulting from standard fractionation. We first establish a benchmark by using the DP algorithm to solve the problem exactly. In this case, we...
Comparison of two approaches to dynamic programming
Broek, van den Pim; Noppen, Joost
2004-01-01
Both in mathematics and in computer science Dynamic Programming is a well known concept. It is an algorithmic technique, which can be used to write efficient algorithms, based on the avoidance of multiple executions of identical subcomputations. Its definition in both disciplines is however quite di
A Dynamic Programming Approach to Constrained Portfolios
DEFF Research Database (Denmark)
Kraft, Holger; Steffensen, Mogens
2013-01-01
This paper studies constrained portfolio problems that may involve constraints on the probability or the expected size of a shortfall of wealth or consumption. Our first contribution is that we solve the problems by dynamic programming, which is in contrast to the existing literature that applies...... the martingale method. More precisely, we construct the non-separable value function by formalizing the optimal constrained terminal wealth to be a (conjectured) contingent claim on the optimal non-constrained terminal wealth. This is relevant by itself, but also opens up the opportunity to derive new solutions...
Dynamic Programming Approach for Exact Decision Rule Optimization
Amin, Talha
2013-01-01
This chapter is devoted to the study of an extension of dynamic programming approach that allows sequential optimization of exact decision rules relative to the length and coverage. It contains also results of experiments with decision tables from UCI Machine Learning Repository. © Springer-Verlag Berlin Heidelberg 2013.
Dynamic Programming Approach for Construction of Association Rule Systems
Alsolami, Fawaz
2016-11-18
In the paper, an application of dynamic programming approach for optimization of association rules from the point of view of knowledge representation is considered. The association rule set is optimized in two stages, first for minimum cardinality and then for minimum length of rules. Experimental results present cardinality of the set of association rules constructed for information system and lower bound on minimum possible cardinality of rule set based on the information obtained during algorithm work as well as obtained results for length.
A mathematical programming approach for sequential clustering of dynamic networks
Silva, Jonathan C.; Bennett, Laura; Papageorgiou, Lazaros G.; Tsoka, Sophia
2016-02-01
A common analysis performed on dynamic networks is community structure detection, a challenging problem that aims to track the temporal evolution of network modules. An emerging area in this field is evolutionary clustering, where the community structure of a network snapshot is identified by taking into account both its current state as well as previous time points. Based on this concept, we have developed a mixed integer non-linear programming (MINLP) model, SeqMod, that sequentially clusters each snapshot of a dynamic network. The modularity metric is used to determine the quality of community structure of the current snapshot and the historical cost is accounted for by optimising the number of node pairs co-clustered at the previous time point that remain so in the current snapshot partition. Our method is tested on social networks of interactions among high school students, college students and members of the Brazilian Congress. We show that, for an adequate parameter setting, our algorithm detects the classes that these students belong more accurately than partitioning each time step individually or by partitioning the aggregated snapshots. Our method also detects drastic discontinuities in interaction patterns across network snapshots. Finally, we present comparative results with similar community detection methods for time-dependent networks from the literature. Overall, we illustrate the applicability of mathematical programming as a flexible, adaptable and systematic approach for these community detection problems. Contribution to the Topical Issue "Temporal Network Theory and Applications", edited by Petter Holme.
Optimization of decision rules based on dynamic programming approach
Zielosko, Beata
2014-01-14
This chapter is devoted to the study of an extension of dynamic programming approach which allows optimization of approximate decision rules relative to the length and coverage. We introduce an uncertainty measure that is the difference between number of rows in a given decision table and the number of rows labeled with the most common decision for this table divided by the number of rows in the decision table. We fix a threshold γ, such that 0 ≤ γ < 1, and study so-called γ-decision rules (approximate decision rules) that localize rows in subtables which uncertainty is at most γ. Presented algorithm constructs a directed acyclic graph Δ γ T which nodes are subtables of the decision table T given by pairs "attribute = value". The algorithm finishes the partitioning of a subtable when its uncertainty is at most γ. The chapter contains also results of experiments with decision tables from UCI Machine Learning Repository. © 2014 Springer International Publishing Switzerland.
Directory of Open Access Journals (Sweden)
Wenjie Bi
2014-01-01
Full Text Available Dynamic portfolio choice is an important problem in finance, but the optimal strategy analysis is difficult when considering multiple stochastic volatility variables such as the stock price, interest rate, and income. Besides, recent research in experimental economics indicates that the agent shows limited attention, considering only the variables with high fluctuations but ignoring those with small ones. By extending the sparse max method, we propose an approach to solve dynamic programming problem with small stochastic volatility and the agent’s bounded rationality. This approach considers the agent’s behavioral factors and avoids effectively the “Curse of Dimensionality” in a dynamic programming problem with more than a few state variables. We then apply it to Merton dynamic portfolio choice model with stochastic volatility and get a tractable solution. Finally, the numerical analysis shows that the bounded rational agent may pay no attention to the varying equity premium and interest rate with small variance.
Dynamic programming approach to optimization of approximate decision rules
Amin, Talha
2013-02-01
This paper is devoted to the study of an extension of dynamic programming approach which allows sequential optimization of approximate decision rules relative to the length and coverage. We introduce an uncertainty measure R(T) which is the number of unordered pairs of rows with different decisions in the decision table T. For a nonnegative real number β, we consider β-decision rules that localize rows in subtables of T with uncertainty at most β. Our algorithm constructs a directed acyclic graph Δβ(T) which nodes are subtables of the decision table T given by systems of equations of the kind "attribute = value". This algorithm finishes the partitioning of a subtable when its uncertainty is at most β. The graph Δβ(T) allows us to describe the whole set of so-called irredundant β-decision rules. We can describe all irredundant β-decision rules with minimum length, and after that among these rules describe all rules with maximum coverage. We can also change the order of optimization. The consideration of irredundant rules only does not change the results of optimization. This paper contains also results of experiments with decision tables from UCI Machine Learning Repository. © 2012 Elsevier Inc. All rights reserved.
Dynamic programming approach for partial decision rule optimization
Amin, Talha
2012-10-04
This paper is devoted to the study of an extension of dynamic programming approach which allows optimization of partial decision rules relative to the length or coverage. We introduce an uncertainty measure J(T) which is the difference between number of rows in a decision table T and number of rows with the most common decision for T. For a nonnegative real number γ, we consider γ-decision rules (partial decision rules) that localize rows in subtables of T with uncertainty at most γ. Presented algorithm constructs a directed acyclic graph Δ γ(T) which nodes are subtables of the decision table T given by systems of equations of the kind "attribute = value". This algorithm finishes the partitioning of a subtable when its uncertainty is at most γ. The graph Δ γ(T) allows us to describe the whole set of so-called irredundant γ-decision rules. We can optimize such set of rules according to length or coverage. This paper contains also results of experiments with decision tables from UCI Machine Learning Repository.
Dynamic programming approach for newborn's incubator humidity control.
Bouattoura, D; Villon, P; Farges, G
1998-01-01
The anatomy, physiology, and biochemistry of the human skin have been studied for a long time. A special interest has been shown in the water permeability of the premature infant's skin, which is known to be an important factor in the maintenance of a controlled water and heat balance. The rate of evaporative heat exchange between the skin surface of a very premature infant and the surrounding incubator air may be so high that evaporative heat loss alone may exceed the infant's total metabolic heat production. However, it has been demonstrated in several investigations published in recent years that basal evaporative water loss can be consistently reduced by increasing the ambient humidity. Nevertheless, the passive humidification system (water reservoir) used in most incubators cannot achieve high and steady humidity levels. In this paper, we propose an active humidification system. The algorithm is based on a combination of optimal control theory and dynamic programming approach. The relative-humidity (R.H.) regulation is performed in range of 35-90% at 33 degrees C with small oscillations (+/- 0.5% R.H.) around the reference value (i.e., prescribed R.H.).
Replacement model of city bus: A dynamic programming approach
Arifin, Dadang; Yusuf, Edhi
2017-06-01
This paper aims to develop a replacement model of city bus vehicles operated in Bandung City. This study is driven from real cases encountered by the Damri Company in the efforts to improve services to the public. The replacement model propounds two policy alternatives: First, to maintain or keep the vehicles, and second is to replace them with new ones taking into account operating costs, revenue, salvage value, and acquisition cost of a new vehicle. A deterministic dynamic programming approach is used to solve the model. The optimization process was heuristically executed using empirical data of Perum Damri. The output of the model is to determine the replacement schedule and the best policy if the vehicle has passed the economic life. Based on the results, the technical life of the bus is approximately 20 years old, while the economic life is an average of 9 (nine) years. It means that after the bus is operated for 9 (nine) years, managers should consider the policy of rejuvenation.
Optimal Charging of Electric Drive Vehicles: A Dynamic Programming Approach
DEFF Research Database (Denmark)
Delikaraoglou, Stefanos; Capion, Karsten Emil; Juul, Nina
2013-01-01
of electric vehicles in a market environment. From the perspective of vehicle operators participating in the electricity spot market, the problem is to optimally charge and discharge the vehicles in response to spot market prices. We consider the case of a vehicle owner who is a price......With the integration of fluctuating renewable production into the electricity system, electric-drive vehicles may contribute to the resulting need for flexibility, given that the market conditions provide sufficient economic incentive. To investigate this, we consider the short-term management......-taker and that of a fleet operator who can influence prices. In both cases, we show how the problem is amenable to dynamic programming with respectively linear and quadratic costs. With discretization of the state space, however, the problem of fleet operation is prone to suffer from the curse of dimensionality and...
Condition-dependent mate choice: A stochastic dynamic programming approach.
Frame, Alicia M; Mills, Alex F
2014-09-01
We study how changing female condition during the mating season and condition-dependent search costs impact female mate choice, and what strategies a female could employ in choosing mates to maximize her own fitness. We address this problem via a stochastic dynamic programming model of mate choice. In the model, a female encounters males sequentially and must choose whether to mate or continue searching. As the female searches, her own condition changes stochastically, and she incurs condition-dependent search costs. The female attempts to maximize the quality of the offspring, which is a function of the female's condition at mating and the quality of the male with whom she mates. The mating strategy that maximizes the female's net expected reward is a quality threshold. We compare the optimal policy with other well-known mate choice strategies, and we use simulations to examine how well the optimal policy fares under imperfect information.
A Dynamic Programming Approach To Length-Limited Huffman Coding
Golin, Mordecai
2008-01-01
The ``state-of-the-art'' in Length Limited Huffman Coding algorithms is the $\\Theta(ND)$-time, $\\Theta(N)$-space one of Hirschberg and Larmore, where $D\\le N$ is the length restriction on the code. This is a very clever, very problem specific, technique. In this note we show that there is a simple Dynamic-Programming (DP) method that solves the problem with the same time and space bounds. The fact that there was an $\\Theta(ND)$ time DP algorithm was previously known; it is a straightforward DP with the Monge property (which permits an order of magnitude speedup). It was not interesting, though, because it also required $\\Theta(ND)$ space. The main result of this paper is the technique developed for reducing the space. It is quite simple and applicable to many other problems modeled by DPs with the Monge property. We illustrate this with examples from web-proxy design and wireless mobile paging.
A novel neural dynamical approach to convex quadratic program and its efficient applications.
Xia, Youshen; Sun, Changyin
2009-12-01
This paper proposes a novel neural dynamical approach to a class of convex quadratic programming problems where the number of variables is larger than the number of equality constraints. The proposed continuous-time and proposed discrete-time neural dynamical approach are guaranteed to be globally convergent to an optimal solution. Moreover, the number of its neurons is equal to the number of equality constraints. In contrast, the number of neurons in existing neural dynamical methods is at least the number of the variables. Therefore, the proposed neural dynamical approach has a low computational complexity. Compared with conventional numerical optimization methods, the proposed discrete-time neural dynamical approach reduces multiplication operation per iteration and has a large computational step length. Computational examples and two efficient applications to signal processing and robot control further confirm the good performance of the proposed approach.
Stochastic optimization in insurance a dynamic programming approach
Azcue, Pablo
2014-01-01
The main purpose of the book is to show how a viscosity approach can be used to tackle control problems in insurance. The problems covered are the maximization of survival probability as well as the maximization of dividends in the classical collective risk model. The authors consider the possibility of controlling the risk process by reinsurance as well as by investments. They show that optimal value functions are characterized as either the unique or the smallest viscosity solution of the associated Hamilton-Jacobi-Bellman equation; they also study the structure of the optimal strategies and show how to find them. The viscosity approach was widely used in control problems related to mathematical finance but until quite recently it was not used to solve control problems related to actuarial mathematical science. This book is designed to familiarize the reader on how to use this approach. The intended audience is graduate students as well as researchers in this area.
A parameter-adaptive dynamic programming approach for inferring cophylogenies
DEFF Research Database (Denmark)
Merkle, Daniel; Middendorf, Martin; Wieseke, Nicolas
2010-01-01
. The proposed method utilizes an event-based concept for reconciliation analyses where the possible events are cospeciations, sortings, duplications, and (host) switches. All known event-based approaches so far assign costs to each type of cophylogenetic events in order to find a cost-minimal reconstruction. Co...
Welte, R; Kretzschmar, M; Leidl, R; Van den Hoek, A; Jager, JC; Postma, MJ
2000-01-01
Background: Models commonly used for the economic assessment of chamydial screening programs do not consider population effects. Goal: To develop a novel dynamic approach for the economic evaluation of chlamydial prevention measures and to determine the cost-effectiveness of a general practitioner-b
Welte, R; Kretzschmar, M; Leidl, R; Van den Hoek, A; Jager, JC; Postma, MJ
2000-01-01
Background: Models commonly used for the economic assessment of chamydial screening programs do not consider population effects. Goal: To develop a novel dynamic approach for the economic evaluation of chlamydial prevention measures and to determine the cost-effectiveness of a general
A multi-objective dynamic programming approach to constrained discrete-time optimal control
Energy Technology Data Exchange (ETDEWEB)
Driessen, B.J.; Kwok, K.S.
1997-09-01
This work presents a multi-objective differential dynamic programming approach to constrained discrete-time optimal control. In the backward sweep of the dynamic programming in the quadratic sub problem, the sub problem input at a stage or time step is solved for in terms of the sub problem state entering that stage so as to minimize the summed immediate and future cost subject to minimizing the summed immediate and future constraint violations, for all such entering states. The method differs from previous dynamic programming methods, which used penalty methods, in that the constraints of the sub problem, which may include terminal constraints and path constraints, are solved exactly if they are solvable; otherwise, their total violation is minimized. Again, the resulting solution of the sub problem is an input history that minimizes the quadratic cost function subject to being a minimizer of the total constraint violation. The expected quadratic convergence of the proposed algorithm is demonstrated on a numerical example.
Nie, Xianghui; Huang, Guo H; Li, Yongping
2009-11-01
This study integrates the concepts of interval numbers and fuzzy sets into optimization analysis by dynamic programming as a means of accounting for system uncertainty. The developed interval fuzzy robust dynamic programming (IFRDP) model improves upon previous interval dynamic programming methods. It allows highly uncertain information to be effectively communicated into the optimization process through introducing the concept of fuzzy boundary interval and providing an interval-parameter fuzzy robust programming method for an embedded linear programming problem. Consequently, robustness of the optimization process and solution can be enhanced. The modeling approach is applied to a hypothetical problem for the planning of waste-flow allocation and treatment/disposal facility expansion within a municipal solid waste (MSW) management system. Interval solutions for capacity expansion of waste management facilities and relevant waste-flow allocation are generated and interpreted to provide useful decision alternatives. The results indicate that robust and useful solutions can be obtained, and the proposed IFRDP approach is applicable to practical problems that are associated with highly complex and uncertain information.
A Generic Top-Down Dynamic-Programming Approach to Prefix-Free Coding
Golin, Mordecai; Yu, Jiajin
2008-01-01
Given a probability distribution over a set of n words to be transmitted, the Huffman Coding problem is to find a minimal-cost prefix free code for transmitting those words. The basic Huffman coding problem can be solved in O(n log n) time but variations are more difficult. One of the standard techniques for solving these variations utilizes a top-down dynamic programming approach. In this paper we show that this approach is amenable to dynamic programming speedup techniques, permitting a speedup of an order of magnitude for many algorithms in the literature for such variations as mixed radix, reserved length and one-ended coding. These speedups are immediate implications of a general structural property that permits batching together the calculation of many DP entries.
An Approach for Dynamic Optimization of Prevention Program Implementation in Stochastic Environments
Kang, Yuncheol; Prabhu, Vittal
The science of preventing youth problems has significantly advanced in developing evidence-based prevention program (EBP) by using randomized clinical trials. Effective EBP can reduce delinquency, aggression, violence, bullying and substance abuse among youth. Unfortunately the outcomes of EBP implemented in natural settings usually tend to be lower than in clinical trials, which has motivated the need to study EBP implementations. In this paper we propose to model EBP implementations in natural settings as stochastic dynamic processes. Specifically, we propose Markov Decision Process (MDP) for modeling and dynamic optimization of such EBP implementations. We illustrate these concepts using simple numerical examples and discuss potential challenges in using such approaches in practice.
Dynamic programming-based hot spot identification approach for pedestrian crashes.
Medury, Aditya; Grembek, Offer
2016-08-01
Network screening techniques are widely used by state agencies to identify locations with high collision concentration, also referred to as hot spots. However, most of the research in this regard has focused on identifying highway segments that are of concern to automobile collisions. In comparison, pedestrian hot spot detection has typically focused on analyzing pedestrian crashes in specific locations, such as at/near intersections, mid-blocks, and/or other crossings, as opposed to long stretches of roadway. In this context, the efficiency of the some of the widely used network screening methods has not been tested. Hence, in order to address this issue, a dynamic programming-based hot spot identification approach is proposed which provides efficient hot spot definitions for pedestrian crashes. The proposed approach is compared with the sliding window method and an intersection buffer-based approach. The results reveal that the dynamic programming method generates more hot spots with a higher number of crashes, while providing small hot spot segment lengths. In comparison, the sliding window method is shown to suffer from shortcomings due to a first-come-first-serve approach vis-à-vis hot spot identification and a fixed hot spot window length assumption.
A dynamical programming approach for controlling the directed abelian Dhar-Ramaswamy model
Cajueiro, Daniel O
2013-01-01
A dynamical programming approach is used to deal with the problem of controlling the directed abelian Dhar-Ramaswamy model on two-dimensional square lattice. Two strategies are considered to obtain explicit results to this task. First, the optimal solution of the problem is characterized by the solution of the Bellman equation obtained by numerical algorithms. Second, the solution is used as a benchmark to value how far from the optimum other heuristics that can be applied to larger systems are. This approach is the first attempt on the direction of schemes for controlling self-organized criticality that are based on optimization principles that consider explicitly a tradeoff between the size of the avalanches and the cost of intervention.
Grammatikopoulos, Vasilis
2012-01-01
The current study attempts to integrate parts of program theory and systems-based procedures in educational program evaluation. The educational program that was implemented, called the "Early Steps" project, proposed that physical education can contribute to various educational goals apart from the usual motor skills improvement. Basic…
Grammatikopoulos, Vasilis
2012-01-01
The current study attempts to integrate parts of program theory and systems-based procedures in educational program evaluation. The educational program that was implemented, called the "Early Steps" project, proposed that physical education can contribute to various educational goals apart from the usual motor skills improvement. Basic…
Grammatikopoulos, Vasilis
2012-01-01
The current study attempts to integrate parts of program theory and systems-based procedures in educational program evaluation. The educational program that was implemented, called the "Early Steps" project, proposed that physical education can contribute to various educational goals apart from the usual motor skills improvement. Basic elements of…
Bellman, Richard
2003-01-01
An introduction to the mathematical theory of multistage decision processes, this text takes a ""functional equation"" approach to the discovery of optimum policies. Written by a leading developer of such policies, it presents a series of methods, uniqueness and existence theorems, and examples for solving the relevant equations. The text examines existence and uniqueness theorems, the optimal inventory equation, bottleneck problems in multistage production processes, a new formalism in the calculus of variation, strategies behind multistage games, and Markovian decision processes. Each chapte
A HYBRID DYNAMIC PROGRAM SLICING
Institute of Scientific and Technical Information of China (English)
Yi Tong; Wu Fangjun
2005-01-01
This letter proposes a hybrid method for computing dynamic program slicing. The key element is to construct a Coverage-Testing-based Dynamic Dependence Graph (CTDDG),which makes use of both dynamic and static information to get execution status. The approach overcomes the limitations of previous dynamic slicing methods, which have to redo slicing if slice criterion changes.
A dynamic programming approach to missing data estimation using neural networks
CSIR Research Space (South Africa)
Nelwamondo, FV
2013-01-01
Full Text Available This paper develops and presents a novel technique for missing data estimation using a combination of dynamic programming, neural networks and genetic algorithms (GA) on suitable subsets of the input data. The method proposed here is well suited...
Directory of Open Access Journals (Sweden)
S. Sofana Reka
2016-09-01
Full Text Available This paper proposes a cloud computing framework in smart grid environment by creating small integrated energy hub supporting real time computing for handling huge storage of data. A stochastic programming approach model is developed with cloud computing scheme for effective demand side management (DSM in smart grid. Simulation results are obtained using GUI interface and Gurobi optimizer in Matlab in order to reduce the electricity demand by creating energy networks in a smart hub approach.
Institute of Scientific and Technical Information of China (English)
HEWei; YANGSuqiong; YUANBaozong; LINBiqin
2004-01-01
Shortest path search has important practical applications and is related to optimization problem.This paper discusses a new algorithm time-synchronous heuristic dynamic programming search, which combined the pruning and global optimization of DP (Dynamic programming) and the partial search of heuristic strategy and found the shortest path in time O(n/kd) (k, d ≥ 1). Furthermore, the algorithm can be applied to find the K shortest paths between a pair of given nodes or all paths less than a given length within the same steps. Finally this algorithm was applied to the shortest path search on the real map and user could use spoken dialog to query shortcut in realtime, 90% of the system responses are correct.
Nagy, Ivan
2017-01-01
This book provides a general theoretical background for constructing the recursive Bayesian estimation algorithms for mixture models. It collects the recursive algorithms for estimating dynamic mixtures of various distributions and brings them in the unified form, providing a scheme for constructing the estimation algorithm for a mixture of components modeled by distributions with reproducible statistics. It offers the recursive estimation of dynamic mixtures, which are free of iterative processes and close to analytical solutions as much as possible. In addition, these methods can be used online and simultaneously perform learning, which improves their efficiency during estimation. The book includes detailed program codes for solving the presented theoretical tasks. Codes are implemented in the open source platform for engineering computations. The program codes given serve to illustrate the theory and demonstrate the work of the included algorithms.
Discrete Time McKean–Vlasov Control Problem: A Dynamic Programming Approach
Energy Technology Data Exchange (ETDEWEB)
Pham, Huyên, E-mail: pham@math.univ-paris-diderot.fr; Wei, Xiaoli, E-mail: tyswxl@gmail.com [Laboratoire de Probabilités et Modèles Aléatoires, CNRS, UMR 7599, Université Paris Diderot (France)
2016-12-15
We consider the stochastic optimal control problem of nonlinear mean-field systems in discrete time. We reformulate the problem into a deterministic control problem with marginal distribution as controlled state variable, and prove that dynamic programming principle holds in its general form. We apply our method for solving explicitly the mean-variance portfolio selection and the multivariate linear-quadratic McKean–Vlasov control problem.
A Dynamic Programming Approach to Finite-horizon Coherent Quantum LQG Control
Vladimirov, Igor G
2011-01-01
The paper considers the coherent quantum Linear Quadratic Gaussian (CQLQG) control problem for time-varying quantum plants governed by linear quantum stochastic differential equations over a bounded time interval. A controller is sought among quantum linear systems satisfying physical realizability (PR) conditions. The latter describe the dynamic equivalence of the system to an open quantum harmonic oscillator and relate its state-space matrices to the free Hamiltonian, coupling and scattering operators of the oscillator. Using the Hamiltonian parameterization of PR controllers, the CQLQG problem is recast into an optimal control problem for a deterministic system governed by a differential Lyapunov equation. The state of this subsidiary system is the symmetric part of the quantum covariance matrix of the plant-controller state vector. The resulting covariance control problem is treated using dynamic programming and Pontryagin's minimum principle. The associated Hamilton-Jacobi-Bellman equation for the minimu...
Optimization and analysis of decision trees and rules: Dynamic programming approach
Alkhalid, Abdulaziz
2013-08-01
This paper is devoted to the consideration of software system Dagger created in KAUST. This system is based on extensions of dynamic programming. It allows sequential optimization of decision trees and rules relative to different cost functions, derivation of relationships between two cost functions (in particular, between number of misclassifications and depth of decision trees), and between cost and uncertainty of decision trees. We describe features of Dagger and consider examples of this systems work on decision tables from UCI Machine Learning Repository. We also use Dagger to compare 16 different greedy algorithms for decision tree construction. © 2013 Taylor and Francis Group, LLC.
Statistics of voltage drop in distribution circuits: a dynamic programming approach
Energy Technology Data Exchange (ETDEWEB)
Turitsyn, Konstantin S [Los Alamos National Laboratory
2010-01-01
We analyze a power distribution line with high penetration of distributed generation and strong variations of power consumption and generation levels. In the presence of uncertainty the statistical description of the system is required to assess the risks of power outages. In order to find the probability of exceeding the constraints for voltage levels we introduce the probability distribution of maximal voltage drop and propose an algorithm for finding this distribution. The algorithm is based on the assumption of random but statistically independent distribution of loads on buses. Linear complexity in the number of buses is achieved through the dynamic programming technique. We illustrate the performance of the algorithm by analyzing a simple 4-bus system with high variations of load levels.
A Fuzzy Programming approach for formation of Virtual Cells under dynamic and uncertain conditions
Directory of Open Access Journals (Sweden)
R.Jayachitra,
2010-06-01
Full Text Available Inspired by principles and advantages of the group technology (GT philosophy, part family formation for a virtual Cellular Manufacturing System (VCMS using Fuzzy logic is designed for dynamic and uncertain conditions. In real manufacturing systems, the input parameters such as part demand and the capacity are fuzzy in nature. In such cases, the fluctuations in part demand and the availability of manufacturing facilities in each period can be regarded as fuzzy. In a dynamic environment, the planning horizon can be divided into smaller time periods where each period and/or each part has different product mix and demand. A mathematical model for virtual cellular manufacturing system as binary-integer programming is proposed to minimize the total costs consisting of fixed machine costs, variable costs of all machines and the logical group movement costs. To verify the behavior of the proposed model, a comprehensive example is solved by a branch- and-bound (B&B method with the LINGO 12.0 software and the virtual cells(VC are formed by defuzzification using maximizing decision level λ (lambda-cut and the computational results are reported and compared with simulated annealing algorithm and rank order clustering algorithm .
ON NONDETERMINISTIC DYNAMIC PROGRAMMING
2008-01-01
R. Bellman left a lot of research problems in his work “Dynamic Programming" (1957). Having received ideas from Bellman, S. Iwamoto has extracted, out of his problems, a problem on nondeterministic dynamic programming (NDP). Instead of stochastic dynamic programming which has been well studied, Iwamoto has opened a gate to NDP. This report presents speci_c optimal solutions for NDPs on continuous state and decision spaces.
Introduction to dynamic programming
Cooper, Leon; Rodin, E Y
1981-01-01
Introduction to Dynamic Programming provides information pertinent to the fundamental aspects of dynamic programming. This book considers problems that can be quantitatively formulated and deals with mathematical models of situations or phenomena that exists in the real world.Organized into 10 chapters, this book begins with an overview of the fundamental components of any mathematical optimization model. This text then presents the details of the application of dynamic programming to variational problems. Other chapters consider the application of dynamic programming to inventory theory, Mark
Amin, Talha
2013-01-01
In the paper, we present a comparison of dynamic programming and greedy approaches for construction and optimization of approximate decision rules relative to the number of misclassifications. We use an uncertainty measure that is a difference between the number of rows in a decision table T and the number of rows with the most common decision for T. For a nonnegative real number γ, we consider γ-decision rules that localize rows in subtables of T with uncertainty at most γ. Experimental results with decision tables from the UCI Machine Learning Repository are also presented. © 2013 Springer-Verlag.
A dynamic programming approach for quickly estimating large network-based MEV models
DEFF Research Database (Denmark)
Mai, Tien; Frejinger, Emma; Fosgerau, Mogens
2017-01-01
by a rooted, directed graph where each node without successor is an alternative. We formulate a family of MEV models as dynamic discrete choice models on graphs of correlation structures and show that the dynamic models are consistent with MEV theory and generalize the network MEV model (Daly and Bierlaire...
Directory of Open Access Journals (Sweden)
McConville Malcolm J
2007-10-01
Full Text Available Abstract Background Gas chromatography-mass spectrometry (GC-MS is a robust platform for the profiling of certain classes of small molecules in biological samples. When multiple samples are profiled, including replicates of the same sample and/or different sample states, one needs to account for retention time drifts between experiments. This can be achieved either by the alignment of chromatographic profiles prior to peak detection, or by matching signal peaks after they have been extracted from chromatogram data matrices. Automated retention time correction is particularly important in non-targeted profiling studies. Results A new approach for matching signal peaks based on dynamic programming is presented. The proposed approach relies on both peak retention times and mass spectra. The alignment of more than two peak lists involves three steps: (1 all possible pairs of peak lists are aligned, and similarity of each pair of peak lists is estimated; (2 the guide tree is built based on the similarity between the peak lists; (3 peak lists are progressively aligned starting with the two most similar peak lists, following the guide tree until all peak lists are exhausted. When two or more experiments are performed on different sample states and each consisting of multiple replicates, peak lists within each set of replicate experiments are aligned first (within-state alignment, and subsequently the resulting alignments are aligned themselves (between-state alignment. When more than two sets of replicate experiments are present, the between-state alignment also employs the guide tree. We demonstrate the usefulness of this approach on GC-MS metabolic profiling experiments acquired on wild-type and mutant Leishmania mexicana parasites. Conclusion We propose a progressive method to match signal peaks across multiple GC-MS experiments based on dynamic programming. A sensitive peak similarity function is proposed to balance peak retention time and peak
Dynamic programming for QFD in PES optimization
Energy Technology Data Exchange (ETDEWEB)
Sorrentino, R. [Mediterranean Univ. of Reggio Calabria, Reggio Calabria (Italy). Dept. of Computer Science and Electrical Technology
2008-07-01
Quality function deployment (QFD) is a method for linking the needs of the customer with design, development, engineering, manufacturing, and service functions. In the electric power industry, QFD is used to help designers concentrate on the most important technical attributes to develop better electrical services. Most optimization approaches used in QFD analysis have been based on integer or linear programming. These approaches perform well in certain circumstances, but there are problems that hinder their practical use. This paper proposed an approach to optimize Power and Energy Systems (PES). A dynamic programming approach was used along with an extended House of Quality to gather information. Dynamic programming was used to allocate the limited resources to the technical attributes. The approach integrated dynamic programming into the electrical service design process. The dynamic programming approach did not require the full relationship curve between technical attributes and customer satisfaction, or the relationship between technical attributes and cost. It only used a group of discrete points containing information about customer satisfaction, technical attributes, and the cost to find the optimal product design. Therefore, it required less time and resources than other approaches. At the end of the optimization process, the value of each technical attribute, the related cost, and the overall customer satisfaction were obtained at the same time. It was concluded that compared with other optimization methods, the dynamic programming method requires less information and the optimal results are more relevant. 21 refs., 2 tabs., 2 figs.
Yu, Rong; Zhong, Weifeng; Xie, Shengli; Zhang, Yan; Zhang, Yun
2016-02-01
As the next-generation power grid, smart grid will be integrated with a variety of novel communication technologies to support the explosive data traffic and the diverse requirements of quality of service (QoS). Cognitive radio (CR), which has the favorable ability to improve the spectrum utilization, provides an efficient and reliable solution for smart grid communications networks. In this paper, we study the QoS differential scheduling problem in the CR-based smart grid communications networks. The scheduler is responsible for managing the spectrum resources and arranging the data transmissions of smart grid users (SGUs). To guarantee the differential QoS, the SGUs are assigned to have different priorities according to their roles and their current situations in the smart grid. Based on the QoS-aware priority policy, the scheduler adjusts the channels allocation to minimize the transmission delay of SGUs. The entire transmission scheduling problem is formulated as a semi-Markov decision process and solved by the methodology of adaptive dynamic programming. A heuristic dynamic programming (HDP) architecture is established for the scheduling problem. By the online network training, the HDP can learn from the activities of primary users and SGUs, and adjust the scheduling decision to achieve the purpose of transmission delay minimization. Simulation results illustrate that the proposed priority policy ensures the low transmission delay of high priority SGUs. In addition, the emergency data transmission delay is also reduced to a significantly low level, guaranteeing the differential QoS in smart grid.
Software Acquisition Program Dynamics
2011-10-24
techniques to avoid these problems The Objective • Improve acquisition program staff decision-making, and thus improve acquisition program outcomes...classroom training, eLearning , certification, and more—to serve the needs of customers and partners worldwide.
Dynamic Programming Foundations and Principles
Sniedovich, Moshe
2010-01-01
Focusing on the modeling and solution of deterministic multistage decision problems, this book looks at dynamic programming as a problem-solving optimization method. With over 400 useful references, this edition discusses the dynamic programming analysis of a problem, illustrates the rationale behind this analysis, and clarifies the theoretical grounds that justify the rationale. It also explains the meaning and role of the concept of state in dynamic programming, examines the purpose and function of the principle of optimality, and outlines solution strategies for problems defiant of conventi
Introduction to stochastic dynamic programming
Ross, Sheldon M; Lukacs, E
1983-01-01
Introduction to Stochastic Dynamic Programming presents the basic theory and examines the scope of applications of stochastic dynamic programming. The book begins with a chapter on various finite-stage models, illustrating the wide range of applications of stochastic dynamic programming. Subsequent chapters study infinite-stage models: discounting future returns, minimizing nonnegative costs, maximizing nonnegative returns, and maximizing the long-run average return. Each of these chapters first considers whether an optimal policy need exist-providing counterexamples where appropriate-and the
Dynamic programming models and applications
Denardo, Eric V
2003-01-01
Introduction to sequential decision processes covers use of dynamic programming in studying models of resource allocation, methods for approximating solutions of control problems in continuous time, production control, more. 1982 edition.
Hybrid Differential Dynamic Programming with Stochastic Search
Aziz, Jonathan; Parker, Jeffrey; Englander, Jacob
2016-01-01
Differential dynamic programming (DDP) has been demonstrated as a viable approach to low-thrust trajectory optimization, namely with the recent success of NASAs Dawn mission. The Dawn trajectory was designed with the DDP-based Static Dynamic Optimal Control algorithm used in the Mystic software. Another recently developed method, Hybrid Differential Dynamic Programming (HDDP) is a variant of the standard DDP formulation that leverages both first-order and second-order state transition matrices in addition to nonlinear programming (NLP) techniques. Areas of improvement over standard DDP include constraint handling, convergence properties, continuous dynamics, and multi-phase capability. DDP is a gradient based method and will converge to a solution nearby an initial guess. In this study, monotonic basin hopping (MBH) is employed as a stochastic search method to overcome this limitation, by augmenting the HDDP algorithm for a wider search of the solution space.
Approximate Dynamic Programming for Self-Learning Control
Institute of Scientific and Technical Information of China (English)
Derong Liu
2005-01-01
This paper introduces a self-learning control approach based on approximate dynamic programming. Dynamic programming was introduced by Bellman in the 1950's for solving optimal control problems of nonlinear dynamical systems. Due to its high computational complexity, the applications of dynamic programming have been limited to simple and small problems. The key step in finding approximate solutions to dynamic programming is to estimate the performance index in dynamic programming. The optimal control signal can then be determined by minimizing (or maximizing) the performance index. Artificial neural networks are very efficient tools in representing the performance index in dynamic programming. This paper assumes the use of neural networks for estimating the performance index in dynamic programming and for generating optimal control signals, thus to achieve optimal control through self-learning.
Concurrency-based approaches to parallel programming
Kale, L.V.; Chrisochoides, N.; Kohl, J.; Yelick, K.
1995-01-01
The inevitable transition to parallel programming can be facilitated by appropriate tools, including languages and libraries. After describing the needs of applications developers, this paper presents three specific approaches aimed at development of efficient and reusable parallel software for irregular and dynamic-structured problems. A salient feature of all three approaches in their exploitation of concurrency within a processor. Benefits of individual approaches such as these can be leveraged by an interoperability environment which permits modules written using different approaches to co-exist in single applications.
Programming an Interpreter Using Molecular Dynamics
Directory of Open Access Journals (Sweden)
C.A. Middelburg
2007-01-01
Full Text Available PGA (ProGram Algebra is an algebra of programs which concerns programs in their simplest form: sequences of instructions. Molecular dynamics is a simple model of computation developed in the setting of PGA, which bears on the use of dynamic data structures in programming.We consider the programming of an interpreter for a program notation that is close to existing assembly languages using PGA with the primitives of molecular dynamics as basic instructions. It happens that, although primarily meant for explaining programming language features relating to the use of dynamic data structures, the collection of primitives of molecular dynamics in itself is suited to our programming wants.
Indecisiveness: A Dynamic, Integrative Approach.
Johnson, Douglas Paul
1990-01-01
Responds to case of Sondra presented in Career Development Quarterly (September 1990). Suggests that her inability to decide on a career may be rooted in long-term personality style, poor ego strength, noisome family dynamics, and/or developmental delay. Recommends an integrative approach incorporating both personal and career counseling. (PVV)
Protein Secondary Structure Prediction Using Dynamic Programming
Institute of Scientific and Technical Information of China (English)
Jing ZHAO; Pei-Ming SONG; Qing FANG; Jian-Hua LUO
2005-01-01
In the present paper, we describe how a directed graph was constructed and then searched for the optimum path using a dynamic programming approach, based on the secondary structure propensity of the protein short sequence derived from a training data set. The protein secondary structure was thus predicted in this way. The average three-state accuracy of the algorithm used was 76.70%.
Dynamical genetic programming in XCSF.
Preen, Richard J; Bull, Larry
2013-01-01
A number of representation schemes have been presented for use within learning classifier systems, ranging from binary encodings to artificial neural networks. This paper presents results from an investigation into using a temporally dynamic symbolic representation within the XCSF learning classifier system. In particular, dynamical arithmetic networks are used to represent the traditional condition-action production system rules to solve continuous-valued reinforcement learning problems and to perform symbolic regression, finding competitive performance with traditional genetic programming on a number of composite polynomial tasks. In addition, the network outputs are later repeatedly sampled at varying temporal intervals to perform multistep-ahead predictions of a financial time series.
Versatile and declarative dynamic programming using pair algebras
Directory of Open Access Journals (Sweden)
Giegerich Robert
2005-09-01
Full Text Available Abstract Background Dynamic programming is a widely used programming technique in bioinformatics. In sharp contrast to the simplicity of textbook examples, implementing a dynamic programming algorithm for a novel and non-trivial application is a tedious and error prone task. The algebraic dynamic programming approach seeks to alleviate this situation by clearly separating the dynamic programming recurrences and scoring schemes. Results Based on this programming style, we introduce a generic product operation of scoring schemes. This leads to a remarkable variety of applications, allowing us to achieve optimizations under multiple objective functions, alternative solutions and backtracing, holistic search space analysis, ambiguity checking, and more, without additional programming effort. We demonstrate the method on several applications for RNA secondary structure prediction. Conclusion The product operation as introduced here adds a significant amount of flexibility to dynamic programming. It provides a versatile testbed for the development of new algorithmic ideas, which can immediately be put to practice.
Programming an interpreter using molecular dynamics
2008-01-01
PGA (ProGram Algebra) is an algebra of programs which concerns programs in their simplest form: sequences of instructions. Molecular dynamics is a simple model of computation developed in the setting of \\PGA, which bears on the use of dynamic data structures in programming. We consider the programming of an interpreter for a program notation that is close to existing assembly languages using PGA with the primitives of molecular dynamics as basic instructions. It happens that, although primari...
Programming an Interpreter Using Molecular Dynamics
2007-01-01
PGA (ProGram Algebra) is an algebra of programs which concerns programs in their simplest form: sequences of instructions. Molecular dynamics is a simple model of computation developed in the setting of PGA, which bears on the use of dynamic data structures in programming.We consider the programming of an interpreter for a program notation that is close to existing assembly languages using PGA with the primitives of molecular dynamics as basic instructions. It happens that, although primarily...
Gate complexity using Dynamic Programming
Sridharan, Srinivas; Gu, Mile; James, Matthew R.
2008-01-01
The relationship between efficient quantum gate synthesis and control theory has been a topic of interest in the quantum control literature. Motivated by this work, we describe in the present article how the dynamic programming technique from optimal control may be used for the optimal synthesis of quantum circuits. We demonstrate simulation results on an example system on SU(2), to obtain plots related to the gate complexity and sample paths for different logic gates.
A programming approach to computability
Kfoury, A J; Arbib, Michael A
1982-01-01
Computability theory is at the heart of theoretical computer science. Yet, ironically, many of its basic results were discovered by mathematical logicians prior to the development of the first stored-program computer. As a result, many texts on computability theory strike today's computer science students as far removed from their concerns. To remedy this, we base our approach to computability on the language of while-programs, a lean subset of PASCAL, and postpone consideration of such classic models as Turing machines, string-rewriting systems, and p. -recursive functions till the final chapter. Moreover, we balance the presentation of un solvability results such as the unsolvability of the Halting Problem with a presentation of the positive results of modern programming methodology, including the use of proof rules, and the denotational semantics of programs. Computer science seeks to provide a scientific basis for the study of information processing, the solution of problems by algorithms, and the design ...
The Modern Temperature-Accelerated Dynamics Approach.
Zamora, Richard J; Uberuaga, Blas P; Perez, Danny; Voter, Arthur F
2016-06-07
Accelerated molecular dynamics (AMD) is a class of MD-based methods used to simulate atomistic systems in which the metastable state-to-state evolution is slow compared with thermal vibrations. Temperature-accelerated dynamics (TAD) is a particularly efficient AMD procedure in which the predicted evolution is hastened by elevating the temperature of the system and then recovering the correct state-to-state dynamics at the temperature of interest. TAD has been used to study various materials applications, often revealing surprising behavior beyond the reach of direct MD. This success has inspired several algorithmic performance enhancements, as well as the analysis of its mathematical framework. Recently, these enhancements have leveraged parallel programming techniques to enhance both the spatial and temporal scaling of the traditional approach. We review the ongoing evolution of the modern TAD method and introduce the latest development: speculatively parallel TAD.
Programming an interpreter using molecular dynamics
Bergstra, J.A.; Middelburg, C.A.
2007-01-01
PGA (ProGram Algebra) is an algebra of programs which concerns programs in their simplest form: sequences of instructions. Molecular dynamics is a simple model of computation developed in the setting of \\PGA, which bears on the use of dynamic data structures in programming. We consider the programmi
Programming an interpreter using molecular dynamics
Bergstra, J.A.; Middelburg, C.A.
2007-01-01
PGA (ProGram Algebra) is an algebra of programs which concerns programs in their simplest form: sequences of instructions. Molecular dynamics is a simple model of computation developed in the setting of \\PGA, which bears on the use of dynamic data structures in programming. We consider the
Dynamic programming algorithms for biological sequence comparison.
Pearson, W R; Miller, W
1992-01-01
Efficient dynamic programming algorithms are available for a broad class of protein and DNA sequence comparison problems. These algorithms require computer time proportional to the product of the lengths of the two sequences being compared [O(N2)] but require memory space proportional only to the sum of these lengths [O(N)]. Although the requirement for O(N2) time limits use of the algorithms to the largest computers when searching protein and DNA sequence databases, many other applications of these algorithms, such as calculation of distances for evolutionary trees and comparison of a new sequence to a library of sequence profiles, are well within the capabilities of desktop computers. In particular, the results of library searches with rapid searching programs, such as FASTA or BLAST, should be confirmed by performing a rigorous optimal alignment. Whereas rapid methods do not overlook significant sequence similarities, FASTA limits the number of gaps that can be inserted into an alignment, so that a rigorous alignment may extend the alignment substantially in some cases. BLAST does not allow gaps in the local regions that it reports; a calculation that allows gaps is very likely to extend the alignment substantially. Although a Monte Carlo evaluation of the statistical significance of a similarity score with a rigorous algorithm is much slower than the heuristic approach used by the RDF2 program, the dynamic programming approach should take less than 1 hr on a 386-based PC or desktop Unix workstation. For descriptive purposes, we have limited our discussion to methods for calculating similarity scores and distances that use gap penalties of the form g = rk. Nevertheless, programs for the more general case (g = q+rk) are readily available. Versions of these programs that run either on Unix workstations, IBM-PC class computers, or the Macintosh can be obtained from either of the authors.
Joint Chance-Constrained Dynamic Programming
Ono, Masahiro; Kuwata, Yoshiaki; Balaram, J. Bob
2012-01-01
This paper presents a novel dynamic programming algorithm with a joint chance constraint, which explicitly bounds the risk of failure in order to maintain the state within a specified feasible region. A joint chance constraint cannot be handled by existing constrained dynamic programming approaches since their application is limited to constraints in the same form as the cost function, that is, an expectation over a sum of one-stage costs. We overcome this challenge by reformulating the joint chance constraint into a constraint on an expectation over a sum of indicator functions, which can be incorporated into the cost function by dualizing the optimization problem. As a result, the primal variables can be optimized by a standard dynamic programming, while the dual variable is optimized by a root-finding algorithm that converges exponentially. Error bounds on the primal and dual objective values are rigorously derived. We demonstrate the algorithm on a path planning problem, as well as an optimal control problem for Mars entry, descent and landing. The simulations are conducted using a real terrain data of Mars, with four million discrete states at each time step.
Joint Chance-Constrained Dynamic Programming
Ono, Masahiro; Kuwata, Yoshiaki; Balaram, J. Bob
2012-01-01
This paper presents a novel dynamic programming algorithm with a joint chance constraint, which explicitly bounds the risk of failure in order to maintain the state within a specified feasible region. A joint chance constraint cannot be handled by existing constrained dynamic programming approaches since their application is limited to constraints in the same form as the cost function, that is, an expectation over a sum of one-stage costs. We overcome this challenge by reformulating the joint chance constraint into a constraint on an expectation over a sum of indicator functions, which can be incorporated into the cost function by dualizing the optimization problem. As a result, the primal variables can be optimized by a standard dynamic programming, while the dual variable is optimized by a root-finding algorithm that converges exponentially. Error bounds on the primal and dual objective values are rigorously derived. We demonstrate the algorithm on a path planning problem, as well as an optimal control problem for Mars entry, descent and landing. The simulations are conducted using a real terrain data of Mars, with four million discrete states at each time step.
BUILDING MATHEMATICAL MODELS IN DYNAMIC PROGRAMMING
Directory of Open Access Journals (Sweden)
LIANA RODICA PATER
2012-05-01
Full Text Available In short, we can say that dynamic programming is a method of optimization of systems, using their mathematical representation in phases or sequences or as we say, periods. Such systems are common in economic studies at the implementation of programs on the most advanced techniques, such as for example that involving cosmic navigation. Another concept that is involved in the study of dynamic programs is the economic horizon (number of periods or phases that a dynamic program needs. This concept often leads to the examination of the convergence of certain variables on infinite horizon. In many cases from the real economy by introducing updating, dynamic programs can be made convergent.
Semiclassical approaches to nuclear dynamics
Magner, A G; Bartel, J
2016-01-01
The extended Gutzwiller trajectory approach is presented for the semiclassical description of nuclear collective dynamics, in line with the main topics of the fruitful activity of V.G. Solovjov. Within the Fermi-liquid droplet model, the leptodermous effective surface approximation was applied to calculations of energies, sum rules and transition densities for the neutron-proton asymmetry of the isovector giant-dipole resonance and found to be in good agreement with the experimental data. By using the Strutinsky shell correction method, the semiclassical collective transport coefficients such as nuclear inertia, friction, stiffness, and moments of inertia can be derived beyond the quantum perturbation approximation of the response function theory and the cranking model.The averaged particle-number dependence of the low-lying collective vibrational states are described in good agreement with basic experimental data, mainly due to an enhancement of the collective inertia as compared to its irrotational flow val...
A dynamic inequality generation scheme for polynomial programming
Ghaddar, B.; Vera Lizcano, J.C.; Anjos, M.F.
2016-01-01
Hierarchies of semidefinite programs have been used to approximate or even solve polynomial programs. This approach rapidly becomes computationally expensive and is often tractable only for problems of small size. In this paper, we propose a dynamic inequality generation scheme to generate valid pol
Dynamic Slicing of Object-Oriented Programs
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
Program slice has many applications such as program debugging,testing, maintena n ce, and complexity measurement. A static slice consists of all statements in pro gram P that may effect the value of variable v at some point p, and a dynamic s lice consists only of statements that influence the value of variable occurrence for specific program inputs. In this paper, we concern the problem of dynamic s licing of object-oriented programs which, to our knowledge, has not been addres s ed in the literatures. To solve this problem, we present the dynamic object-ori e nted dependence graph (DODG)which is an arc-classified digraph to explicitly re p resent various dynamic dependence between statement instances for a particular e xecution of an object-oriented program. Based on the DODG, we present a two-ph as e backward algorithm for computing a dynamic slice of an object-oriented program.
Path planning for complex terrain navigation via dynamic programming
Energy Technology Data Exchange (ETDEWEB)
Kwok, K.S.; Driessen, B.J.
1998-12-31
This work considers the problem of planning optimal paths for a mobile robot traversing complex terrain. In addition to the existing obstacles, locations in the terrain where the slope is too steep for the mobile robot to navigate safely without tipping over become mathematically equivalent to extra obstacles. To solve the optimal path problem, the authors use a dynamic programming approach. The dynamic programming approach utilized herein does not suffer the difficulties associated with spurious local minima that the artificial potential field approaches do. In fact, a globally optimal solution is guaranteed to be found if a feasible solution exists. The method is demonstrated on several complex examples including very complex terrains.
Evolutionary approaches of economic dynamics (In French)
Yildizoglu, Murat
2009-01-01
This chapter presents the methods and contributions of evolutionary approach to economic dynamics. First, we expose why economic dynamics can indeed be considered as evolutionary. Second, we discuss sources of diversity and selection mechanisms that drive these dynamics, in the context of industrial dynamics. Third, we expose the main methods of this approach. Last, we give a partial survey of this approach’s contributions in economic systems covering a full spectrum, from organizational to m...
Genomic Signal Search by Dynamic Programming
Institute of Scientific and Technical Information of China (English)
ZHENG Wei-Mou
2003-01-01
A general and flexible multi-motif model is proposed based on dynamic programming. By extending theGibbs sampler to the dynamic programming and introducing temperature, an efficient algorithm is developed. Branchpoint signalsequences and translation initiation sequences extracted from the rice genome are then examined.
Nonlinear Approach in Nuclear Dynamics
Gridnev, K. A.; Kartavenko, V. G.; Greiner, W.
2002-11-01
Attention is focused on the various approaches that use the concept of nonlinear dispersive waves (solitons) in nonrelativistic nuclear physics. The problem of dynamical instability and clustering (stable fragments formation) in a breakup of excited nuclear systems are considered from the points of view of the soliton concept. It is shown that the volume (spinodal) instability can be associated with nonlinear terms, and the surface (Rayleigh-Taylor type) instability, with the dispersion terms in the evolution equations. The both instabilities may compensate each other and lead to stable solutions (solitons). A static scission configuration in cold ternary fission is considered in the framework of mean field approach. We suggest to use the inverse mean field method to solve single-particle Schrödinger equation, instead of constrained selfconsistent Hartree-Fock equations. It is shown, that it is possible to simulate one-dimensional three-center system in the approximation of reflectless single-particle potentials. The soliton-like solutions of the Korteweg-de Vries equation are using to describe collective excitations of nuclei observed in inelastic alpha-particle and proton scattering. The analogy between fragmentation into parts of nuclei and buckyballs has led us to the idea of light nuclei as quasi-crystals. We establish that the quasi-crystalline structure can be formed when the distance between the alpha-particles is comparable with the length of the De Broglia wave of the alpha-particle. Applying this model to the scattering of alpha-particles we obtain that the form factor of the clusterized nucleus can be factorized into the formfactor of the cluster and the density of clusters in the nucleus. It gives possibility to study the distribution of clusters in nuclei and to resolve what kind of distribution we are dealing with: a surface or volume one.
Semiclassical approaches to nuclear dynamics
Energy Technology Data Exchange (ETDEWEB)
Magner, A. G., E-mail: magner@kinr.kiev.ua; Gorpinchenko, D. V. [Institute for Nuclear Research NASU (Ukraine); Bartel, J. [Université de Strasbourg, Institut Pluridisciplinaire Hubert Curien, CNRS/IN2P3 (France)
2017-01-15
The extended Gutzwiller trajectory approach is presented for the semiclassical description of nuclear collective dynamics, in line with the main topics of the fruitful activity of V.G. Solovjov. Within the Fermi-liquid droplet model, the leptodermous effective surface approximation was applied to calculations of energies, sum rules, and transition densities for the neutron–proton asymmetry of the isovector giant-dipole resonance and found to be in good agreement with the experimental data. By using the Strutinsky shell correction method, the semiclassical collective transport coefficients, such as nuclear inertia, friction, stiffness, and moments of inertia, can be derived beyond the quantum perturbation approximation of the response function theory and the cranking model. The averaged particle-number dependences of the low-lying collective vibrational states are described in good agreement with the basic experimental data, mainly due to the enhancement of the collective inertia as compared to its irrotational flow value. Shell components of the moment of inertia are derived in terms of the periodic-orbit free-energy shell corrections. A good agreement between the semiclassical extended Thomas–Fermi moments of inertia with shell corrections and the quantum results is obtained for different nuclear deformations and particle numbers. Shell effects are shown to be exponentially dampted out with increasing temperature in all the transport coefficients.
Symbolic Tensor Calculus -- Functional and Dynamic Approach
Woszczyna, A; Czaja, W; Golda, Z A
2016-01-01
In this paper, we briefly discuss the dynamic and functional approach to computer symbolic tensor analysis. The ccgrg package for Wolfram Language/Mathematica is used to illustrate this approach. Some examples of applications are attached.
Organisations’ evolutionary dynamics: a group dynamics approach
Directory of Open Access Journals (Sweden)
Germán Eduardo Vargas
2010-04-01
Full Text Available Colombian entrepreneurs’ straggling, reactionary and inertial orientation has been inconsistently lustified by the availability of internal and leveraged resources, a concept intensifying deficient technological capacity. Company activity (seen as being a socioeconomic unit has been integrally orientated within an evolutionary framework by company identity and cohesion as well as adaptation and evolutionary mechanisms. The present document uses a group dynamics’ model to illustrate how knowledge-based strategic orientation and integration for innovation have become an imperative for development, from slight leverage, distinguishing between two evolutionary company forms: traditional economic (inertial, as they introduce sporadic incremental improvements and modern companies (dynamic and radical innovators. Revealing conclusions obtained from such model may be used for intervening in and modernising company activity.
A Unified Approach to Modeling and Programming
DEFF Research Database (Denmark)
Madsen, Ole Lehrmann; Møller-Pedersen, Birger
2010-01-01
of this paper is to go back to the future and get inspiration from SIMULA and propose a unied approach. In addition to reintroducing the contributions of SIMULA and the Scandinavian approach to object-oriented programming, we do this by discussing a number of issues in modeling and programming and argue3 why we......SIMULA was a language for modeling and programming and provided a unied approach to modeling and programming in contrast to methodologies based on structured analysis and design. The current development seems to be going in the direction of separation of modeling and programming. The goal...
Integrating Pareto Optimization into Dynamic Programming
Directory of Open Access Journals (Sweden)
Thomas Gatter
2016-01-01
Full Text Available Pareto optimization combines independent objectives by computing the Pareto front of the search space, yielding a set of optima where none scores better on all objectives than any other. Recently, it was shown that Pareto optimization seamlessly integrates with algebraic dynamic programming: when scoring schemes A and B can correctly evaluate the search space via dynamic programming, then so can Pareto optimization with respect to A and B. However, the integration of Pareto optimization into dynamic programming opens a wide range of algorithmic alternatives, which we study in substantial detail in this article, using real-world applications in biosequence analysis, a field where dynamic programming is ubiquitous. Our results are two-fold: (1 We introduce the operation of a “Pareto algebra product” in the dynamic programming framework of Bellman’s GAP. Users of this framework can now ask for Pareto optimization with a single keystroke. Careful evaluation of the implementation alternatives by means of an extended Bellman’s GAP compiler demonstrates the dependence of the best implementation choice on the application at hand. (2 We extract from our experiments several pieces of advice to programmers who do not use a system such as Bellman’s GAP, but who choose to hand-craft their dynamic programming recurrences, incorporating Pareto optimization from scratch.
Dynamic Programming: An Introduction by Example
Zietz, Joachim
2007-01-01
The author introduces some basic dynamic programming techniques, using examples, with the help of the computer algebra system "Maple". The emphasis is on building confidence and intuition for the solution of dynamic problems in economics. To integrate the material better, the same examples are used to introduce different techniques. One covers the…
Dynamical system approach to phyllotaxis
DEFF Research Database (Denmark)
D'ovidio, Francesco; Mosekilde, Erik
2000-01-01
and not a dynamical system, mainly because new active elements are added at each step, and thus the dimension of the "natural" phase space is not conserved. Here a construction is presented by which a well defined dynamical system can be obtained, and a bifurcation analysis can be carried out. Stable and unstable...... of the Jacobian, and thus the eigenvalues, is given. It is likely that problems of the above type often arise in biology, and especially in morphogenesis, where growing systems are modeled....
An Approach to Programming Based on Concepts
Savinov, Alexandr
2007-01-01
In this paper we describe a new approach to programming which generalizes object-oriented programming. It is based on using a new programming construct, called concept, which generalizes classes. Concept is defined as a pair of two classes: one reference class and one object class. Each concept has a parent concept which is specified using inclusion relation generalizing inheritance. We describe several important mechanisms such as reference resolution, context stack, dual methods and life-cycle management, inheritance and polymorphism. This approach to programming is positioned as a new programming paradigm and therefore we formulate its main principles and rules.
Solution Methods for Stochastic Dynamic Linear Programs.
1980-12-01
Linear Programming, IIASA , Laxenburg, Austria, June 2-6, 1980. [2] Aghili, P., R.H., Cramer and H.W. Thompson, "On the applicability of two- stage...Laxenburg, Austria, May, 1978. [52] Propoi, A. and V. Krivonozhko, ’The simplex method for dynamic linear programs", RR-78-14, IIASA , Vienna, Austria
Dynamical System Approaches to Combinatorial Optimization
DEFF Research Database (Denmark)
Starke, Jens
2013-01-01
Several dynamical system approaches to combinatorial optimization problems are described and compared. These include dynamical systems derived from penalty methods; the approach of Hopfield and Tank; self-organizing maps, that is, Kohonen networks; coupled selection equations; and hybrid methods....... Many of them are investigated analytically, and the costs of the solutions are compared numerically with those of solutions obtained by simulated annealing and the costs of a global optimal solution. Using dynamical systems, a solution to the combinatorial optimization problem emerges in the limit...... of large times as an asymptotically stable point of the dynamics. The obtained solutions are often not globally optimal but good approximations of it. Dynamical system and neural network approaches are appropriate methods for distributed and parallel processing. Because of the parallelization...
Dynamic Frames Based Verification Method for Concurrent Java Programs
Mostowski, Wojciech
2016-01-01
In this paper we discuss a verification method for concurrent Java programs based on the concept of dynamic frames. We build on our earlier work that proposes a new, symbolic permission system for concurrent reasoning and we provide the following new contributions. First, we describe our approach
A Dynamic Programming Algorithm for the k-Haplotyping Problem
Institute of Scientific and Technical Information of China (English)
Zhen-ping Li; Ling-yun Wu; Yu-ying Zhao; Xiang-sun Zhang
2006-01-01
The Minimum Fragments Removal (MFR) problem is one of the haplotyping problems: given a set of fragments, remove the minimum number of fragments so that the resulting fragments can be partitioned into k classes of non-conflicting subsets. In this paper, we formulate the k-MFR problem as an integer linear programming problem, and develop a dynamic programming approach to solve the k-MFR problem for both the gapless and gap cases.
A Unified Approach for Developing Efficient Algorithmic Programs
Institute of Scientific and Technical Information of China (English)
薛锦云
1997-01-01
A unified approach called partition-and-recur for developing efficient and correct algorithmic programs is presented.An algorithm(represented by recurrence and initiation)is separated from program,and special attention is paid to algorithm manipulation rather than proram calculus.An algorithm is exactly a set of mathematical formulae.It is easier for formal erivation and proof.After getting efficient and correct algorithm,a trivial transformation is used to get a final rogram,The approach covers several known algorithm design techniques,e.g.dynamic programming,greedy,divide-and-conquer and enumeration,etc.The techniques of partition and recurrence are not new.Partition is a general approach for dealing with complicated objects and is typically used in divide-and-conquer approach.Recurrence is used in algorithm analysis,in developing loop invariants and dynamic programming approach.The main contribution is combining two techniques used in typical algorithm development into a unified and systematic approach to develop general efficient algorithmic programs and presenting a new representation of algorithm that is easier for understanding and demonstrating the correctness and ingenuity of algorithmicprograms.
Attack diagnosis on binary executables using dynamic program slicing
Huang, Shan; Zheng, Yudi; Zhang, Ruoyu
2011-12-01
Nowadays, the level of the practically used programs is often complex and of such a large scale so that it is not as easy to analyze and debug them as one might expect. And it is quite difficult to diagnose attacks and find vulnerabilities in such large-scale programs. Thus, dynamic program slicing becomes a popular and effective method for program comprehension and debugging since it can reduce the analysis scope greatly and drop useless data that do not influence the final result. Besides, most of existing dynamic slicing tools perform dynamic slicing in the source code level, but the source code is not easy to obtain in practice. We believe that we do need some kinds of systems to help the users understand binary programs. In this paper, we present an approach of diagnosing attacks using dynamic backward program slicing based on binary executables, and provide a dynamic binary slicing tool named DBS to analyze binary executables precisely and efficiently. It computes the set of instructions that may have affected or been affected by slicing criterion set in certain location of the binary execution stream. This tool also can organize the slicing results by function call graphs and control flow graphs clearly and hierarchically.
A dynamic systems approach to family assessment
van Geert, PLC; Lichtwarck-Aschoff, A
2005-01-01
The dynamic systems approach provides a general framework for studying processes. Properties of that approach are applied to the issue of fan-lily assessment. The description covers methods of assessment of short-term processes (e.g., dyadic interaction) and long-term processes (e.g., changes in int
Planar multibody dynamics formulation, programming and applications
Nikravesh, Parviz E
2007-01-01
Introduction Multibody Mechanical Systems Types of Analyses Methods of Formulation Computer Programming Application Examples Unit System Remarks Preliminaries Reference Axes Scalars and Vectors Matrices Vector, Array, and Matrix Differentiation Equations and Expressions Remarks Problems Fundamentals of Kinematics A Particle Kinematics of a Rigid Body Definitions Remarks Problems Fundamentals of Dynamics Newton's Laws of Motion Dynamics of a Body Force Elements Applied Forces Reaction Force Remarks Problems Point-Coordinates: Kinematics Multipoint
Configuring Airspace Sectors with Approximate Dynamic Programming
Bloem, Michael; Gupta, Pramod
2010-01-01
In response to changing traffic and staffing conditions, supervisors dynamically configure airspace sectors by assigning them to control positions. A finite horizon airspace sector configuration problem models this supervisor decision. The problem is to select an airspace configuration at each time step while considering a workload cost, a reconfiguration cost, and a constraint on the number of control positions at each time step. Three algorithms for this problem are proposed and evaluated: a myopic heuristic, an exact dynamic programming algorithm, and a rollouts approximate dynamic programming algorithm. On problem instances from current operations with only dozens of possible configurations, an exact dynamic programming solution gives the optimal cost value. The rollouts algorithm achieves costs within 2% of optimal for these instances, on average. For larger problem instances that are representative of future operations and have thousands of possible configurations, excessive computation time prohibits the use of exact dynamic programming. On such problem instances, the rollouts algorithm reduces the cost achieved by the heuristic by more than 15% on average with an acceptable computation time.
An Approach to Programming Based on Concepts
Savinov, Alexandr
2007-01-01
In this paper we describe a new approach to programming which generalizes object-oriented programming. It is based on using a new programming construct, called concept, which generalizes classes. Concept is defined as a pair of two classes: one reference class and one object class. Each concept has a parent concept which is specified using inclusion relation generalizing inheritance. We describe several important mechanisms such as reference resolution, context stack, dual methods and life-cy...
Comparing approaches to generic programming in Haskell
Hinze, R.; Jeuring, J.T.; Löh, A.
2007-01-01
The last decade has seen a number of approaches to data- type-generic programming: PolyP, Functorial ML, `Scrap Your Boiler- plate', Generic Haskell, `Generics for the Masses', etc. The approaches vary in sophistication and target audience: some propose full-blown pro- gramming languages, some sugge
A Novel Approach for Solving Semidefinite Programs
Directory of Open Access Journals (Sweden)
Hong-Wei Jiao
2014-01-01
Full Text Available A novel linearizing alternating direction augmented Lagrangian approach is proposed for effectively solving semidefinite programs (SDP. For every iteration, by fixing the other variables, the proposed approach alternatively optimizes the dual variables and the dual slack variables; then the primal variables, that is, Lagrange multipliers, are updated. In addition, the proposed approach renews all the variables in closed forms without solving any system of linear equations. Global convergence of the proposed approach is proved under mild conditions, and two numerical problems are given to demonstrate the effectiveness of the presented approach.
Microsoft Dynamics NAV 7 programming cookbook
Raul, Rakesh
2013-01-01
Written in the style of a cookbook. Microsoft Dynamics NAV 7 Programming Cookbook is full of recipes to help you get the job done.If you are a junior / entry-level NAV developer then the first half of the book is designed primarily for you. You may or may not have any experience programming. It focuses on the basics of NAV programming.If you are a mid-level NAV developer, you will find these chapters explain how to think outside of the NAV box when building solutions. There are also recipes that senior developers will find useful.
Two stage gear tooth dynamics program
Boyd, Linda S.
1989-01-01
The epicyclic gear dynamics program was expanded to add the option of evaluating the tooth pair dynamics for two epicyclic gear stages with peripheral components. This was a practical extension to the program as multiple gear stages are often used for speed reduction, space, weight, and/or auxiliary units. The option was developed for either stage to be a basic planetary, star, single external-external mesh, or single external-internal mesh. The two stage system allows for modeling of the peripherals with an input mass and shaft, an output mass and shaft, and a connecting shaft. Execution of the initial test case indicated an instability in the solution with the tooth paid loads growing to excessive magnitudes. A procedure to trace the instability is recommended as well as a method of reducing the program's computation time by reducing the number of boundary condition iterations.
Expansion of epicyclic gear dynamic analysis program
Boyd, Linda Smith; Pike, James A.
1987-01-01
The multiple mesh/single stage dynamics program is a gear tooth analysis program which determines detailed geometry, dynamic loads, stresses, and surface damage factors. The program can analyze a variety of both epicyclic and single mesh systems with spur or helical gear teeth including internal, external, and buttress tooth forms. The modifications refine the options for the flexible carrier and flexible ring gear rim and adds three options: a floating Sun gear option; a natural frequency option; and a finite element compliance formulation for helical gear teeth. The option for a floating Sun incorporates two additional degrees of freedom at the Sun center. The natural frequency option evaluates the frequencies of planetary, star, or differential systems as well as the effect of additional springs at the Sun center and those due to a flexible carrier and/or ring gear rim. The helical tooth pair finite element calculated compliance is obtained from an automated element breakup of the helical teeth and then is used with the basic gear dynamic solution and stress postprocessing routines. The flexible carrier or ring gear rim option for planetary and star spur gear systems allows the output torque per carrier and ring gear rim segment to vary based on the dynamic response of the entire system, while the total output torque remains constant.
基于贝尔曼动态规划的服务恢复决策方法%Approach of service recovery decision-making based on Bellman dynamic programming
Institute of Scientific and Technical Information of China (English)
何蕾; 任江春; 王志英
2008-01-01
基于面向服务的架构(SOA),针对可控分布式信息系统中服务的特点并借鉴服务组合思想,详细分析了信息系统的典型服务过程,提出一种基于贝尔曼动态规划的服务恢复决策算法.通过逻辑层网络自组织和评价标准制定2个步骤,将服务恢复过程中恢复决策问题转化为人工智能领域的规划问题,并对此规划问题使用贝尔曼动态规划算法,解决了确保服务质量(QoS)的前提下,最优服务恢复方案制定与应急响应路径选择问题.仿真实验验证了方法的最优性与合理性,算法复杂性理论分析及与传统方法的性能对比均表明了该方法的高效性.%Based on service-oriented architecture (SOA), a Bellman-dynamic-programming-based approach of service recovery decision-making is proposed to make valid recovery decisions. Both the attribute and the process of services in the controllable distributed information system are analyzed as the preparatory work. Using the idea of service composition as a reference, the approach translates the recovery decision-making into a planning problem regarding artificial intelligence (AI) through two steps. The first is the self-organization based on a logical view of the network, and the second is the definition of evaluation standards. Applying Bellman dynamic programming to solve the planning problem, the approach offers timely emergency response and optimal recovery source selection, meeting multiple QoS (quality of service )requirements. Experimental results demonstrate the rationality and optimality of the approach, and the theoretical analysis of its computational complexity and the comparison with conventional methods exhibit its high efficiency.
Dynamical maximum entropy approach to flocking
Cavagna, Andrea; Giardina, Irene; Ginelli, Francesco; Mora, Thierry; Piovani, Duccio; Tavarone, Raffaele; Walczak, Aleksandra M.
2014-04-01
We derive a new method to infer from data the out-of-equilibrium alignment dynamics of collectively moving animal groups, by considering the maximum entropy model distribution consistent with temporal and spatial correlations of flight direction. When bird neighborhoods evolve rapidly, this dynamical inference correctly learns the parameters of the model, while a static one relying only on the spatial correlations fails. When neighbors change slowly and the detailed balance is satisfied, we recover the static procedure. We demonstrate the validity of the method on simulated data. The approach is applicable to other systems of active matter.
Understanding the Entrepreneurial Process: a Dynamic Approach
Directory of Open Access Journals (Sweden)
Vânia Maria Jorge Nassif
2010-04-01
Full Text Available There is considerable predominance in the adoption of perspectives based on characteristics in research into entrepreneurship. However, most studies describe the entrepreneur from a static or snapshot approach; very few adopt a dynamic perspective. The aim of this study is to contribute to the enhancement of knowledge concerning entrepreneurial process dynamics through an understanding of the values, characteristics and actions of the entrepreneur over time. By focusing on personal attributes, we have developed a framework that shows the importance of affective and cognitive aspects of entrepreneurs and the way that they evolve during the development of their business.
Eradication of Ebola Based on Dynamic Programming
Zhu, Jia-Ming; Wang, Lu; Liu, Jia-Bao
2016-01-01
This paper mainly studies the eradication of the Ebola virus, proposing a scientific system, including three modules for the eradication of Ebola virus. Firstly, we build a basic model combined with nonlinear incidence rate and maximum treatment capacity. Secondly, we use the dynamic programming method and the Dijkstra Algorithm to set up M-S (storage) and several delivery locations in West Africa. Finally, we apply the previous results to calculate the total cost, production cost, storage cost, and shortage cost. PMID:27313655
On a Natural Dynamics for Linear Programming
Straszak, Damian
2015-01-01
In this paper we study dynamics inspired by Physarum polycephalum (a slime mold) for solving linear programs [NTY00, IJNT11, JZ12]. These dynamics are arrived at by a local and mechanistic interpretation of the inner workings of the slime mold and a global optimization perspective has been lacking even in the simplest of instances. Our first result is an interpretation of the dynamics as an optimization process. We show that Physarum dynamics can be seen as a steepest-descent type algorithm on a certain Riemannian manifold. Moreover, we prove that the trajectories of Physarum are in fact paths of optimizers to a parametrized family of convex programs, in which the objective is a linear cost function regularized by an entropy barrier. Subsequently, we rigorously establish several important properties of solution curves of Physarum. We prove global existence of such solutions and show that they have limits, being optimal solutions of the underlying LP. Finally, we show that the discretization of the Physarum dy...
Sandia Dynamic Materials Program Strategic Plan.
Energy Technology Data Exchange (ETDEWEB)
Flicker, Dawn Gustine [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Benage, John F. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Desjarlais, Michael P. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Knudson, Marcus D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Leifeste, Gordon T. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lemke, Raymond W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Mattsson, Thomas [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Wise, Jack L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
2017-05-01
Materials in nuclear and conventional weapons can reach multi-megabar pressures and 1000s of degree temperatures on timescales ranging from microseconds to nanoseconds. Understanding the response of complex materials under these conditions is important for designing and assessing changes to nuclear weapons. In the next few decades, a major concern will be evaluating the behavior of aging materials and remanufactured components. The science to enable the program to underwrite decisions quickly and confidently on use, remanufacturing, and replacement of these materials will be critical to NNSA’s new Stockpile Responsiveness Program. Material response is also important for assessing the risks posed by adversaries or proliferants. Dynamic materials research, which refers to the use of high-speed experiments to produce extreme conditions in matter, is an important part of NNSA’s Stockpile Stewardship Program.
An analytic approach to cyber adversarial dynamics
Sweeney, Patrick; Cybenko, George
2012-06-01
To date, cyber security investment by both the government and commercial sectors has been largely driven by the myopic best response of players to the actions of their adversaries and their perception of the adversarial environment. However, current work in applying traditional game theory to cyber operations typically assumes that games exist with prescribed moves, strategies, and payos. This paper presents an analytic approach to characterizing the more realistic cyber adversarial metagame that we believe is being played. Examples show that understanding the dynamic metagame provides opportunities to exploit an adversary's anticipated attack strategy. A dynamic version of a graph-based attack-defend game is introduced, and a simulation shows how an optimal strategy can be selected for success in the dynamic environment.
Multiscale Model Approach for Magnetization Dynamics Simulations
De Lucia, Andrea; Tretiakov, Oleg A; Kläui, Mathias
2016-01-01
Simulations of magnetization dynamics in a multiscale environment enable rapid evaluation of the Landau-Lifshitz-Gilbert equation in a mesoscopic sample with nanoscopic accuracy in areas where such accuracy is required. We have developed a multiscale magnetization dynamics simulation approach that can be applied to large systems with spin structures that vary locally on small length scales. To implement this, the conventional micromagnetic simulation framework has been expanded to include a multiscale solving routine. The software selectively simulates different regions of a ferromagnetic sample according to the spin structures located within in order to employ a suitable discretization and use either a micromagnetic or an atomistic model. To demonstrate the validity of the multiscale approach, we simulate the spin wave transmission across the regions simulated with the two different models and different discretizations. We find that the interface between the regions is fully transparent for spin waves with f...
Evaluating Pain Education Programs: An Integrated Approach
Directory of Open Access Journals (Sweden)
Adam Dubrowski
2011-01-01
Full Text Available Evaluation of educational programs and assessment of learning are essential to maintain high-standard health science education, which includes pain education. Current models of program evaluations applied to the education of the health professions, such as the Kirkpatrick model, are mainly outcome based. More recently, efforts have been made to examine other process-based models such as the Context Input Process Product model. The present article proposes an approach that integrates both outcome- and process-based models with models of clinical performance assessment to provide a deeper understanding of a program function. Because assessment instruments are a critical part of program evaluation, it is suggested that standardization and rigour should be used in their selection, development and adaptation. The present article suggests an alternative to currently used models in pain education evaluation.
Approaches to Learning to Control Dynamic Uncertainty
Directory of Open Access Journals (Sweden)
Magda Osman
2015-10-01
Full Text Available In dynamic environments, when faced with a choice of which learning strategy to adopt, do people choose to mostly explore (maximizing their long term gains or exploit (maximizing their short term gains? More to the point, how does this choice of learning strategy influence one’s later ability to control the environment? In the present study, we explore whether people’s self-reported learning strategies and levels of arousal (i.e., surprise, stress correspond to performance measures of controlling a Highly Uncertain or Moderately Uncertain dynamic environment. Generally, self-reports suggest a preference for exploring the environment to begin with. After which, those in the Highly Uncertain environment generally indicated they exploited more than those in the Moderately Uncertain environment; this difference did not impact on performance on later tests of people’s ability to control the dynamic environment. Levels of arousal were also differentially associated with the uncertainty of the environment. Going beyond behavioral data, our model of dynamic decision-making revealed that, in actual fact, there was no difference in exploitation levels between those in the highly uncertain or moderately uncertain environments, but there were differences based on sensitivity to negative reinforcement. We consider the implications of our findings with respect to learning and strategic approaches to controlling dynamic uncertainty.
Adaptive dynamic programming with applications in optimal control
Liu, Derong; Wang, Ding; Yang, Xiong; Li, Hongliang
2017-01-01
This book covers the most recent developments in adaptive dynamic programming (ADP). The text begins with a thorough background review of ADP making sure that readers are sufficiently familiar with the fundamentals. In the core of the book, the authors address first discrete- and then continuous-time systems. Coverage of discrete-time systems starts with a more general form of value iteration to demonstrate its convergence, optimality, and stability with complete and thorough theoretical analysis. A more realistic form of value iteration is studied where value function approximations are assumed to have finite errors. Adaptive Dynamic Programming also details another avenue of the ADP approach: policy iteration. Both basic and generalized forms of policy-iteration-based ADP are studied with complete and thorough theoretical analysis in terms of convergence, optimality, stability, and error bounds. Among continuous-time systems, the control of affine and nonaffine nonlinear systems is studied using the ADP app...
Hydrothermal scheduling via extended differential dynamic programming and mixed coordination
Energy Technology Data Exchange (ETDEWEB)
Tang, J. [Alfred Univ., NY (United States). Div. of Electrical Engineering; Luh, P.B. [Univ. of Connecticut, Storrs, CT (United States). Dept. of Electrical and Systems Engineering
1995-11-01
This paper addresses short-term scheduling of hydrothermal systems by using extended differential dynamic programming and mixed coordination. The problem is first decomposed into a thermal subproblem and a hydro subproblem by relaxing the supply-demand constraints. The thermal subproblem is solved analytically. The hydro subproblem is further decomposed into a set of smaller problems that can be solved in parallel. Extended differential dynamic programming and mixed coordination are used to solve the hydro subproblem. Two problems are tested and the results show that the new approach performs well under a simulated parallel processing environment, and high speedup is obtained. The method is then extended to handle unpredictable changes in natural inflow by utilizing the variational feedback nature of the control strategy. A quick estimate on the impact of an unpredictable change on total cost is also obtained. Numerical results show that estimates are accurate, and unpredictable change in natural inflow can be quickly and effectively handled.
Adaptive Dynamic Programming for Control Algorithms and Stability
Zhang, Huaguang; Luo, Yanhong; Wang, Ding
2013-01-01
There are many methods of stable controller design for nonlinear systems. In seeking to go beyond the minimum requirement of stability, Adaptive Dynamic Programming for Control approaches the challenging topic of optimal control for nonlinear systems using the tools of adaptive dynamic programming (ADP). The range of systems treated is extensive; affine, switched, singularly perturbed and time-delay nonlinear systems are discussed as are the uses of neural networks and techniques of value and policy iteration. The text features three main aspects of ADP in which the methods proposed for stabilization and for tracking and games benefit from the incorporation of optimal control methods: • infinite-horizon control for which the difficulty of solving partial differential Hamilton–Jacobi–Bellman equations directly is overcome, and proof provided that the iterative value function updating sequence converges to the infimum of all the value functions obtained by admissible control law sequences; • finite-...
Managing institutional dynamics: generalisation of modern approaches
Directory of Open Access Journals (Sweden)
Mazur Olena Ye.
2013-03-01
Full Text Available The article presents a critical analysis and systematisation of modern approaches to state management of development of institutional structures. It identifies the most popular approaches to management of institutional dynamics: implantations or shock therapy, import (transplantation and its modifications (institutional experimenting and building intermediary institutions, growing institutions and modification (elevation and cultivation and influence upon external factors of institution development. The article builds structural and logical schemes to each approach and identifies main shortcomings and restrictions of their application. It justifies prospectiveness and universality of the theory of priority of external factors in re-formation of socio-economic institutions. It offers a direction of further scientific studies on development of a specific methodology of re-formation of a specific institution on the basis of a selected and justified common strategy.
A first approach to filament dynamics
Energy Technology Data Exchange (ETDEWEB)
Silva, P E S; De Abreu, F Vistulo; Dias, R G [Department of Physics, University of Aveiro (Portugal); Simoes, R, E-mail: fva@ua.p [I3N-Institute for Nanostructures, Nanomodelling and Nanofabrication (Portugal)
2010-11-15
Modelling elastic filament dynamics is a topic of high interest due to the wide range of applications. However, it has reached a high level of complexity in the literature, making it unaccessible to a beginner. In this paper we explain the main steps involved in the computational modelling of the dynamics of an elastic filament. We first derive equations governing the dynamics of an elastic lament suitable for a computer simulation implementation. The derivation starts from the relation between forces and potential energy in conservative systems in order to derive the equation of motion of any bead in the filament. Only two-dimensional movements are considered, but extensions to three dimensions can follow similar lines. Suggestions for computer implementations are provided in Matlab as well as an example of application related to the generation of musical sounds. This example allows a critical analysis of the numerical results obtained using a cross-disciplinary perspective. Since derivations start from basic physics equations, use simple calculus and computational implementations are straightforward, this paper proposes a different approach to introduce simple molecular dynamics simulations or animations of real systems in undergraduate elasticity or computer modelling courses.
Gauge-invariant approach to quark dynamics
Sazdjian, H
2016-01-01
The main aspects of a gauge-invariant approach to the description of quark dynamics in the nonperturbative regime of QCD are first reviewed. In particular, the role of the parallel transport operation in constructing gauge-invariant Green's functions is presented, and the relevance of Wilson loops for the representation of the interaction is emphasized. Recent developments, based on the use of polygonal lines for the parallel transport operation, are then presented. An integro-differential equation is obtained for the quark Green's function defined with a phase factor along a single, straight line segment. It is solved exactly and analytically in the case of two-dimensional QCD in the large $N_c$ limit. The solution displays the dynamical mass generation phenomenon for quarks, with an infinite number of branch-cut singularities that are stronger than simple poles.
Fuzzy Multi-objective Linear Programming Approach
Directory of Open Access Journals (Sweden)
Amna Rehmat
2007-07-01
Full Text Available Traveling salesman problem (TSP is one of the challenging real-life problems, attracting researchers of many fields including Artificial Intelligence, Operations Research, and Algorithm Design and Analysis. The problem has been well studied till now under different headings and has been solved with different approaches including genetic algorithms and linear programming. Conventional linear programming is designed to deal with crisp parameters, but information about real life systems is often available in the form of vague descriptions. Fuzzy methods are designed to handle vague terms, and are most suited to finding optimal solutions to problems with vague parameters. Fuzzy multi-objective linear programming, an amalgamation of fuzzy logic and multi-objective linear programming, deals with flexible aspiration levels or goals and fuzzy constraints with acceptable deviations. In this paper, a methodology, for solving a TSP with imprecise parameters, is deployed using fuzzy multi-objective linear programming. An example of TSP with multiple objectives and vague parameters is discussed.
A Novel Inconsistency Prevention Approach to Dynamic Updating of Web Applications
Directory of Open Access Journals (Sweden)
Seyed Habib Seifzadeh
2013-01-01
Full Text Available Software update requires that running program is stopped, patched and then restarted from start. This cycle mainly causes disruptions to the programs' execution which may be undesirable. Disruptions could turn out to be more problematic in the web applications, because they usually have to provide round-the-clock services. Nowadays, there are systems called Dynamic Updating Systems which are able to update programs without disruption. However, a dynamic updating system capable of updating web applications is infrequent to date. The present study aims to propose approaches needed to compose a web-based dynamic updating system. Providing these approaches, we have focused on preserving programs' consistency. To this end, different states of a web application are considered, and actions which the dynamic updating system must perform in each state are described. This paper concludes with a discussion about the implementation and the evaluation of the proposed approaches.
Automated Flight Routing Using Stochastic Dynamic Programming
Ng, Hok K.; Morando, Alex; Grabbe, Shon
2010-01-01
Airspace capacity reduction due to convective weather impedes air traffic flows and causes traffic congestion. This study presents an algorithm that reroutes flights in the presence of winds, enroute convective weather, and congested airspace based on stochastic dynamic programming. A stochastic disturbance model incorporates into the reroute design process the capacity uncertainty. A trajectory-based airspace demand model is employed for calculating current and future airspace demand. The optimal routes minimize the total expected traveling time, weather incursion, and induced congestion costs. They are compared to weather-avoidance routes calculated using deterministic dynamic programming. The stochastic reroutes have smaller deviation probability than the deterministic counterpart when both reroutes have similar total flight distance. The stochastic rerouting algorithm takes into account all convective weather fields with all severity levels while the deterministic algorithm only accounts for convective weather systems exceeding a specified level of severity. When the stochastic reroutes are compared to the actual flight routes, they have similar total flight time, and both have about 1% of travel time crossing congested enroute sectors on average. The actual flight routes induce slightly less traffic congestion than the stochastic reroutes but intercept more severe convective weather.
Runway Scheduling Using Generalized Dynamic Programming
Montoya, Justin; Wood, Zachary; Rathinam, Sivakumar
2011-01-01
A generalized dynamic programming method for finding a set of pareto optimal solutions for a runway scheduling problem is introduced. The algorithm generates a set of runway fight sequences that are optimal for both runway throughput and delay. Realistic time-based operational constraints are considered, including miles-in-trail separation, runway crossings, and wake vortex separation. The authors also model divergent runway takeoff operations to allow for reduced wake vortex separation. A modeled Dallas/Fort Worth International airport and three baseline heuristics are used to illustrate preliminary benefits of using the generalized dynamic programming method. Simulated traffic levels ranged from 10 aircraft to 30 aircraft with each test case spanning 15 minutes. The optimal solution shows a 40-70 percent decrease in the expected delay per aircraft over the baseline schedulers. Computational results suggest that the algorithm is promising for real-time application with an average computation time of 4.5 seconds. For even faster computation times, two heuristics are developed. As compared to the optimal, the heuristics are within 5% of the expected delay per aircraft and 1% of the expected number of runway operations per hour ad can be 100x faster.
Constraint Logic Programming approach to protein structure prediction
Directory of Open Access Journals (Sweden)
Fogolari Federico
2004-11-01
Full Text Available Abstract Background The protein structure prediction problem is one of the most challenging problems in biological sciences. Many approaches have been proposed using database information and/or simplified protein models. The protein structure prediction problem can be cast in the form of an optimization problem. Notwithstanding its importance, the problem has very seldom been tackled by Constraint Logic Programming, a declarative programming paradigm suitable for solving combinatorial optimization problems. Results Constraint Logic Programming techniques have been applied to the protein structure prediction problem on the face-centered cube lattice model. Molecular dynamics techniques, endowed with the notion of constraint, have been also exploited. Even using a very simplified model, Constraint Logic Programming on the face-centered cube lattice model allowed us to obtain acceptable results for a few small proteins. As a test implementation their (known secondary structure and the presence of disulfide bridges are used as constraints. Simplified structures obtained in this way have been converted to all atom models with plausible structure. Results have been compared with a similar approach using a well-established technique as molecular dynamics. Conclusions The results obtained on small proteins show that Constraint Logic Programming techniques can be employed for studying protein simplified models, which can be converted into realistic all atom models. The advantage of Constraint Logic Programming over other, much more explored, methodologies, resides in the rapid software prototyping, in the easy way of encoding heuristics, and in exploiting all the advances made in this research area, e.g. in constraint propagation and its use for pruning the huge search space.
A semidefinite programming approach for solving Multiobjective Linear Programming
Blanco, Víctor; Ben-Ali, Safae El-Haj
2011-01-01
Several algorithms are available in the literature for finding the entire set of Pareto-optimal solutions in MultiObjective Linear Programming (MOLP). However, it has not been proposed so far an interior point algorithm that finds all Pareto-optimal solutions of MOLP. We present an explicit construction, based on a transformation of any MOLP into a finite sequence of SemiDefinite Programs (SDP), the solutions of which give the entire set of Pareto-optimal extreme points solutions of MOLP. These SDP problems are solved by interior point methods; thus our approach provides a pseudo-polynomial interior point methodology to find the set of Pareto-optimal solutions of MOLP.
Decomposing the misery index: A dynamic approach
Directory of Open Access Journals (Sweden)
Ivan K. Cohen
2014-12-01
Full Text Available The misery index (the unweighted sum of unemployment and inflation rates was probably the first attempt to develop a single statistic to measure the level of a population’s economic malaise. In this letter, we develop a dynamic approach to decompose the misery index using two basic relations of modern macroeconomics: the expectations-augmented Phillips curve and Okun’s law. Our reformulation of the misery index is closer in spirit to Okun’s idea. However, we are able to offer an improved version of the index, mainly based on output and unemployment. Specifically, this new Okun’s index measures the level of economic discomfort as a function of three key factors: (1 the misery index in the previous period; (2 the output gap in growth rate terms; and (3 cyclical unemployment. This dynamic approach differs substantially from the standard one utilised to develop the misery index, and allow us to obtain an index with five main interesting features: (1 it focuses on output, unemployment and inflation; (2 it considers only objective variables; (3 it allows a distinction between short-run and long-run phenomena; (4 it places more importance on output and unemployment rather than inflation; and (5 it weights recessions more than expansions.
Dynamical Systems Approach to Magnetised Cosmological Perturbations
Hobbs, S; Hobbs, Stacey; Dunsby, Peter K. S.
2000-01-01
Assuming a large-scale homogeneous magnetic field, we follow the covariant and gauge-invariant approach used by Tsagas and Barrow to describe the evolution of density and magnetic field inhomogeneities and curvature perturbations in a matter-radiation universe. We use a two parameter approximation scheme to linearize their exact non-linear general-relativistic equations for magneto-hydrodynamic evolution. Using a two-fluid approach we set up the governing equations as a fourth order autonomous dynamical system. Analysis of the equilibrium points for the radiation dominated era lead to solutions similar to the super-horizon modes found analytically by Tsagas and Maartens. We find that a study of the dynamical system in the dust-dominated era leads naturally to a magnetic critical length scale closely related to the Jeans Length. Depending on the size of wavelengths relative to this scale, these solutions show three distinct behaviours: large-scale stable growing modes, intermediate decaying modes, and small-sc...
A complex-valued neural dynamical optimization approach and its stability analysis.
Zhang, Songchuan; Xia, Youshen; Zheng, Weixing
2015-01-01
In this paper, we propose a complex-valued neural dynamical method for solving a complex-valued nonlinear convex programming problem. Theoretically, we prove that the proposed complex-valued neural dynamical approach is globally stable and convergent to the optimal solution. The proposed neural dynamical approach significantly generalizes the real-valued nonlinear Lagrange network completely in the complex domain. Compared with existing real-valued neural networks and numerical optimization methods for solving complex-valued quadratic convex programming problems, the proposed complex-valued neural dynamical approach can avoid redundant computation in a double real-valued space and thus has a low model complexity and storage capacity. Numerical simulations are presented to show the effectiveness of the proposed complex-valued neural dynamical approach.
Editorial Special issue on approximate dynamic programming and reinforcement learning
Institute of Scientific and Technical Information of China (English)
Silvia Ferrari; Jagannathan Sarangapani; Frank L. Lewis
2011-01-01
We are extremely pleased to present this special issue of the Journal of Control Theory and Applications.Approximate dynamic programming (ADP) is a general and effective approach for solving optimal control and estimation problems by adapting to uncertain environments over time.ADP optimizes the sensing objectives accrued over a future time interval with respect to an adaptive control law,conditioned on prior knowledge of the system,its state,and uncertainties.A numerical search over the present value of the control minimizes a Hamilton-Jacobi-Bellman (HJB) equation providing a basis for real-time,approximate optimal control.
Robot trajectory planning via dynamic programming
Energy Technology Data Exchange (ETDEWEB)
Dohrmann, C.R.; Robinett, R.D.
1994-03-01
The method of dynamic programming is applied to three example problems dealing with robot trajectory planning. The first two examples involve end-effector tracking of a straight line with rest-to-rest motions of planar two-link and three-link rigid robots. These examples illustrate the usefulness of the method for producing smooth trajectories either in the presence or absence of joint redundancies. The last example demonstrates the use of the method for rest-to-rest maneuvers of a single-link manipulator with a flexible payload. Simulation results for this example display interesting symmetries that are characteristic of such maneuvers. Details concerning the implementation and computational aspects of the method are discussed.
Pareto optimization in algebraic dynamic programming.
Saule, Cédric; Giegerich, Robert
2015-01-01
Pareto optimization combines independent objectives by computing the Pareto front of its search space, defined as the set of all solutions for which no other candidate solution scores better under all objectives. This gives, in a precise sense, better information than an artificial amalgamation of different scores into a single objective, but is more costly to compute. Pareto optimization naturally occurs with genetic algorithms, albeit in a heuristic fashion. Non-heuristic Pareto optimization so far has been used only with a few applications in bioinformatics. We study exact Pareto optimization for two objectives in a dynamic programming framework. We define a binary Pareto product operator [Formula: see text] on arbitrary scoring schemes. Independent of a particular algorithm, we prove that for two scoring schemes A and B used in dynamic programming, the scoring scheme [Formula: see text] correctly performs Pareto optimization over the same search space. We study different implementations of the Pareto operator with respect to their asymptotic and empirical efficiency. Without artificial amalgamation of objectives, and with no heuristics involved, Pareto optimization is faster than computing the same number of answers separately for each objective. For RNA structure prediction under the minimum free energy versus the maximum expected accuracy model, we show that the empirical size of the Pareto front remains within reasonable bounds. Pareto optimization lends itself to the comparative investigation of the behavior of two alternative scoring schemes for the same purpose. For the above scoring schemes, we observe that the Pareto front can be seen as a composition of a few macrostates, each consisting of several microstates that differ in the same limited way. We also study the relationship between abstract shape analysis and the Pareto front, and find that they extract information of a different nature from the folding space and can be meaningfully combined.
Systems approaches to study root architecture dynamics
Directory of Open Access Journals (Sweden)
Candela eCuesta
2013-12-01
Full Text Available The plant root system is essential for providing anchorage to the soil, supplying minerals and water, and synthesizing metabolites. It is a dynamic organ modulated by external cues such as environmental signals, water and nutrients availability, salinity and others. Lateral roots are initiated from the primary root post-embryonically, after which they progress through discrete developmental stages which can be independently controlled, providing a high level of plasticity during root system formation.Within this review, main contributions are presented, from the classical forward genetic screens to the more recent high-throughput approaches, combined with computer model predictions, dissecting how lateral roots and thereby root system architecture is established and developed.
A Simulation Program for Dynamic Infrared (IR) Spectra
Zoerb, Matthew C.; Harris, Charles B.
2013-01-01
A free program for the simulation of dynamic infrared (IR) spectra is presented. The program simulates the spectrum of two exchanging IR peaks based on simple input parameters. Larger systems can be simulated with minor modifications. The program is available as an executable program for PCs or can be run in MATLAB on any operating system. Source…
Spatial cluster detection using dynamic programming
Directory of Open Access Journals (Sweden)
Sverchkov Yuriy
2012-03-01
Full Text Available Abstract Background The task of spatial cluster detection involves finding spatial regions where some property deviates from the norm or the expected value. In a probabilistic setting this task can be expressed as finding a region where some event is significantly more likely than usual. Spatial cluster detection is of interest in fields such as biosurveillance, mining of astronomical data, military surveillance, and analysis of fMRI images. In almost all such applications we are interested both in the question of whether a cluster exists in the data, and if it exists, we are interested in finding the most accurate characterization of the cluster. Methods We present a general dynamic programming algorithm for grid-based spatial cluster detection. The algorithm can be used for both Bayesian maximum a-posteriori (MAP estimation of the most likely spatial distribution of clusters and Bayesian model averaging over a large space of spatial cluster distributions to compute the posterior probability of an unusual spatial clustering. The algorithm is explained and evaluated in the context of a biosurveillance application, specifically the detection and identification of Influenza outbreaks based on emergency department visits. A relatively simple underlying model is constructed for the purpose of evaluating the algorithm, and the algorithm is evaluated using the model and semi-synthetic test data. Results When compared to baseline methods, tests indicate that the new algorithm can improve MAP estimates under certain conditions: the greedy algorithm we compared our method to was found to be more sensitive to smaller outbreaks, while as the size of the outbreaks increases, in terms of area affected and proportion of individuals affected, our method overtakes the greedy algorithm in spatial precision and recall. The new algorithm performs on-par with baseline methods in the task of Bayesian model averaging. Conclusions We conclude that the dynamic
A Structural Dynamics Approach to the Simulation of Spacecraft Control/Structure Interaction
Young, J. W.
1985-01-01
A relatively simple approach to the analysis of linear spacecraft control/structure interaction problems is presented. The approach uses a commercially available structural system dynamic analysis package for both controller and plant dynamics, thus obviating the need to transfer data between separate programs. The unilateral coupling between components in the control system block diagram is simulated using sparse matrix stiffness and damping elements available in the structural dynamic code. The approach is illustrated with a series of simple tutorial examples of a rigid spacecraft core with flexible appendages.
Integrated Network Decompositions and Dynamic Programming for Graph Optimization (INDDGO)
Energy Technology Data Exchange (ETDEWEB)
2012-05-31
The INDDGO software package offers a set of tools for finding exact solutions to graph optimization problems via tree decompositions and dynamic programming algorithms. Currently the framework offers serial and parallel (distributed memory) algorithms for finding tree decompositions and solving the maximum weighted independent set problem. The parallel dynamic programming algorithm is implemented on top of the MADNESS task-based runtime.
Application of a Dynamic Programming Algorithm for Weapon Target Assignment
2016-02-01
UNCLASSIFIED UNCLASSIFIED Application of a Dynamic Programming Algorithm for Weapon Target Assignment Lloyd Hammond Weapons and...Combat Systems Division Defence Science and Technology Group DST Group-TR-3221 ABSTRACT Threat evaluation and weapon assignment...dynamic programming algorithm for Weapon Target Assignment which, after more rigorous testing, could be used as a concept demonstrator and as an auxiliary
Lower Bounds for Tropical Circuits and Dynamic Programs
Jukna, Stasys
2014-01-01
Tropical circuits are circuits with Min and Plus, or Max and Plus operations as gates. Their importance stems from their intimate relation to dynamic programming algorithms. The power of tropical circuits lies somewhere between that of monotone boolean circuits and monotone arithmetic circuits. In this paper we present some lower bounds arguments for tropical circuits, and hence, for dynamic programs.
Evaluation of Electric Power Procurement Strategies by Stochastic Dynamic Programming
Saisho, Yuichi; Hayashi, Taketo; Fujii, Yasumasa; Yamaji, Kenji
In deregulated electricity markets, the role of a distribution company is to purchase electricity from the wholesale electricity market at randomly fluctuating prices and to provide it to its customers at a given fixed price. Therefore the company has to take risk stemming from the uncertainties of electricity prices and/or demand fluctuation instead of the customers. The way to avoid the risk is to make a bilateral contact with generating companies or install its own power generation facility. This entails the necessity to develop a certain method to make an optimal strategy for electric power procurement. In such a circumstance, this research has the purpose for proposing a mathematical method based on stochastic dynamic programming and additionally considering the characteristics of the start-up cost of electric power generation facility to evaluate strategies of combination of the bilateral contract and power auto-generation with its own facility for procuring electric power in deregulated electricity market. In the beginning we proposed two approaches to solve the stochastic dynamic programming, and they are a Monte Carlo simulation method and a finite difference method to derive the solution of a partial differential equation of the total procurement cost of electric power. Finally we discussed the influences of the price uncertainty on optimal strategies of power procurement.
A Knowledge—Based Approach to Program Synthesis from Examples
Institute of Scientific and Technical Information of China (English)
朱鸿; 金凌紫
1991-01-01
This paper proposes an approach to synthesize functional programs of Backus' FP system[1,2] from input/output instances.Based on a theory of orthogonal expansion of programs3[,4],the task of program synthesis is expressed in program equations,and fulfilled by solving them according to the knowledge about the equivalence between programs.Some general knowledge of solving program equations with a number of examples are given in the paper.
Optimization of Algorithms Using Extensions of Dynamic Programming
AbouEisha, Hassan M.
2017-04-09
We study and answer questions related to the complexity of various important problems such as: multi-frontal solvers of hp-adaptive finite element method, sorting and majority. We advocate the use of dynamic programming as a viable tool to study optimal algorithms for these problems. The main approach used to attack these problems is modeling classes of algorithms that may solve this problem using a discrete model of computation then defining cost functions on this discrete structure that reflect different complexity measures of the represented algorithms. As a last step, dynamic programming algorithms are designed and used to optimize those models (algorithms) and to obtain exact results on the complexity of the studied problems. The first part of the thesis presents a novel model of computation (element partition tree) that represents a class of algorithms for multi-frontal solvers along with cost functions reflecting various complexity measures such as: time and space. It then introduces dynamic programming algorithms for multi-stage and bi-criteria optimization of element partition trees. In addition, it presents results based on optimal element partition trees for famous benchmark meshes such as: meshes with point and edge singularities. New improved heuristics for those benchmark meshes were ob- tained based on insights of the optimal results found by our algorithms. The second part of the thesis starts by introducing a general problem where different problems can be reduced to and show how to use a decision table to model such problem. We describe how decision trees and decision tests for this table correspond to adaptive and non-adaptive algorithms for the original problem. We present exact bounds on the average time complexity of adaptive algorithms for the eight elements sorting problem. Then bounds on adaptive and non-adaptive algorithms for a variant of the majority problem are introduced. Adaptive algorithms are modeled as decision trees whose depth
ALPprolog --- A New Logic Programming Method for Dynamic Domains
Drescher, Conrad
2011-01-01
Logic programming is a powerful paradigm for programming autonomous agents in dynamic domains, as witnessed by languages such as Golog and Flux. In this work we present ALPprolog, an expressive, yet efficient, logic programming language for the online control of agents that have to reason about incomplete information and sensing actions.
Eid, Chaker; Millham, Richard
2012-01-01
In this paper, we discuss the visual programming approach to teaching introductory programming courses and then compare this approach with that of procedural programming. The involved cognitive levels of students, as beginning students are introduced to different types of programming concepts, are correlated to the learning processes of…
A novel formal approach to program slicing
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
Program slicing is a well-known program analysis technique that extracts the elements of a program related to a particular computation. The current slicing methods, however, are singular (mainly based on a program or system dependence graph), and lack good reusability and flexibility. In this paper, we present a novel formal method for program slicing, modular monadic program slicing, which abstracts the computation of program slicing as a slice monad transformer, and applies it to semantic descriptions of the program analyzed in a modular way, forming the corresponding monadic slicing algorithms. The modular abstraction mechanism allows our slicing method to possess excellent modularity and language-flexibility properties. We also give the related axioms of our slice monad transformer, the proof of the correctness and the implementation of monadic slicing algorithms. We reveal the relations of our algorithms and graph-reachable slicing algorithms.
Cognitive agent programming : A semantic approach
Riemsdijk, M.B. van
2006-01-01
In this thesis we are concerned with the design and investigation of dedicated programming languages for programming agents. We focus in particular on programming languages for rational agents, i.e., flexibly behaving computing entities that are able to make "good" decisions about what to do. An imp
Reversible circuit synthesis by genetic programming using dynamic gate libraries
Abubakar, Mustapha Y.; Jung, Low Tang; Zakaria, Nordin; Younes, Ahmed; Abdel-Aty, Abdel-Haleem
2017-06-01
We have defined a new method for automatic construction of reversible logic circuits by using the genetic programming approach. The choice of the gate library is 100% dynamic. The algorithm is capable of accepting all possible combinations of the following gate types: NOT TOFFOLI, NOT PERES, NOT CNOT TOFFOLI, NOT CNOT SWAP FREDKIN, NOT CNOT TOFFOLI SWAP FREDKIN, NOT CNOT PERES, NOT CNOT SWAP FREDKIN PERES, NOT CNOT TOFFOLI PERES and NOT CNOT TOFFOLI SWAP FREDKIN PERES. Our method produced near optimum circuits in some cases when a particular subset of gate types was used in the library. Meanwhile, in some cases, optimal circuits were produced due to the heuristic nature of the algorithm. We compared the outcomes of our method with several existing synthesis methods, and it was shown that our algorithm performed relatively well compared to the previous synthesis methods in terms of the output efficiency of the algorithm and execution time as well.
An Improved Dynamic Programming Method for Automatic Stratigraphic Correlation
Institute of Scientific and Technical Information of China (English)
Yan Hanjie; Yan Hong; Xiang Zhucong; Wang Yanjiang
2003-01-01
An improved dynamic programming algorithm is proposed for reducing the possible mismatching of layer in multi-well correlation. Compared with the standard dynamic programming algorithm, this method restricts the searching range during layer matching. It can not only avoid possible mismatching between sample and target layer, but also reduce the time spent on layer correlation. The result of applying the improved methods on the data processed by standard method before indicates that the improved one is more effective and timesaving for the multi-well correlation system than conventional dynamic programming algorithm.
Approximate Dynamic Programming Solving the Curses of Dimensionality
Powell, Warren B
2011-01-01
Praise for the First Edition "Finally, a book devoted to dynamic programming and written using the language of operations research (OR)! This beautiful book fills a gap in the libraries of OR specialists and practitioners."-Computing Reviews This new edition showcases a focus on modeling and computation for complex classes of approximate dynamic programming problems Understanding approximate dynamic programming (ADP) is vital in order to develop practical and high-quality solutions to complex industrial problems, particularly when those problems involve making decisions in the presence of unce
Cursive script segmentation and recognition by dynamic programming
Man, Gary M. T.; Poon, Joe C. H.
1993-04-01
Traditionally, the problem of cursive script recognition has been handled in two fundamental ways: one based on the global approach and the other on the segmentation approach. In this paper, we present an inexact segmentation approach to segment the word into letters or even strokes. Our algorithm searches for high curvature points along the lower contour of the image profile. These points are then treated as segment points and marked as potential letter boundaries. Using the histogram profile, an initial estimation of the word length is made. Yet, this estimated word length may be adjusted later. In the process, dynamic programming is used as a general optimization technique to produce a list of possible candidates of the same word length. If the score of these candidates cannot meet some recognition criteria, the word length is re-estimated and another set of candidates are generated. Eventually, an entropy- based measure is provided for comparison among candidates of different word length. In our system, a contextual postprocessor can easily be added to further improve the recognition rate. But in this instance, we have an additional advantage in that a large number of candidates of variable word length are available for selection and even some words with unrecognized letters may also be taken into consideration. In this paper, some experiments are also carried out to evaluate the performance of our novel algorithm.
A Boolean Approach to Interactive Program Planning
George Abonyi; Nigel Howard
1980-01-01
Program planning refers to the process of selecting an integrated set of projects for implementation. Ultimately, decisions tend to be "political" in the sense that they involve compromises and tradeoffs among different interests, though the arguments may be couched in technical terms. Program planning may be structured as a multi-stage process. One stage involves the assessment of various alternatives for the project components of the program. A second stage then involves the selection of th...
Using a Hybrid Approach to Facilitate Learning Introductory Programming
Cakiroglu, Unal
2013-01-01
In order to facilitate students' understanding in introductory programming courses, different types of teaching approaches were conducted. In this study, a hybrid approach including comment first coding (CFC), analogy and template approaches were used. The goal was to investigate the effect of such a hybrid approach on students' understanding in…
Humanoid robot simulator: a realistic dynamics approach
Lima, José; Gonçalves, José; Costa, Paulo; Moreira, António
2008-01-01
This paper describes a humanoid robot simulator with realistic dynamics. As simulation is a powerful tool for speeding up the control software development, the suggested accurate simulator allows to accomplish this goal. The simulator, based on the Open Dynamics Engine and GLScene graphics library, provides instant visual feedback and allows the user to test any control strategy without damaging the real robot in the early stages of the development. The proposed simulator also captures some c...
A Deductive Approach to Programming Methodology.
1981-12-01
of the Workshop on Logics of Programs (Yorktown-Heights, NY), Springer- Verlag Lecture Notes in Computer Science , 1981. [3] Z. Manna, "Verification of...Specifications" Proceedings of the Workshop on Logics of Programs (Yorktown-Heights), NY, Springer-Verlag Lecture Notes in Computer Science , 1981. (5] Z
A Novel Approach for Collaborative Pair Programming
Goel, Sanjay; Kathuria, Vanshi
2010-01-01
The majority of an engineer's time in the software industry is spent working with other programmers. Agile methods of software development like eXtreme Programming strongly rely upon practices like daily meetings and pair programming. Hence, the need to learn the skill of working collaboratively is of primary importance for software developers.…
Approximate Dynamic Programming in Tracking Control of a Robotic Manipulator
Marcin Szuster; Piotr Gierlak
2016-01-01
This article focuses on the implementation of an approximate dynamic programming algorithm in the discrete tracking control system of the three-degrees of freedom Scorbot-ER 4pc robotic manipulator. The controlled system is included in an articulated robots group which uses rotary joints to access their work space. The main part of the control system is a dual heuristic dynamic programming algorithm that consists of two structures designed in the form of neural networks: an actor and a critic...
Optimal Design of Measurement Programs for the Parameter Identification of Dynamic Systems
DEFF Research Database (Denmark)
Kirkegaard, Poul Henning; Sørensen, John Dalsgaard; Brincker, Rune
The design of a measured program devoted to parameter identification of structural dynamic systems is considered, the design problem is formulated as an optimization problem due to minimize the total expected cost of the measurement program. All the calculations are based on a priori knowledge an...... in a simply supported plane, vibrating beam model. Results show optimal number of sensors and their locations....... and engineering judgement. One of the contribution of the approach is that the optimal nmber of sensors can be estimated. This is sown in an numerical example where the proposed approach is demonstrated. The example is concerned with design of a measurement program for estimating the modal damping parameters...
Incremental approximate dynamic programming for nonlinear flight control design
Zhou, Y.; Van Kampen, E.J.; Chu, Q.P.
2015-01-01
A self-learning adaptive flight control design for non-linear systems allows reliable and effective operation of flight vehicles in a dynamic environment. Approximate dynamic programming (ADP) provides a model-free and computationally effective process for designing adaptive linear optimal
Program Partitioning using Dynamic Trust Models
DEFF Research Database (Denmark)
Søndergaard, Dan; Probst, Christian W.; Jensen, Christian D.;
2006-01-01
-based scenarios. Language-based technologies have been suggested to support developers of those applications---the \\$\\backslash\\$emph{Decentralized Label Model} and \\$\\backslash\\$emph{Secure Program Partitioning} allow to annotate programs with security specifications, and to partition the annotated program...... across a set of hosts, obeying both the annotations and the trust relation between the principals. The resulting applications guarantee \\$\\backslash\\$emph{by construction} that safety and confidentiality of both data and computations are ensured. In this work, we develop a generalised version...
INDDGO: Integrated Network Decomposition & Dynamic programming for Graph Optimization
Energy Technology Data Exchange (ETDEWEB)
Groer, Christopher S [ORNL; Sullivan, Blair D [ORNL; Weerapurage, Dinesh P [ORNL
2012-10-01
It is well-known that dynamic programming algorithms can utilize tree decompositions to provide a way to solve some \\emph{NP}-hard problems on graphs where the complexity is polynomial in the number of nodes and edges in the graph, but exponential in the width of the underlying tree decomposition. However, there has been relatively little computational work done to determine the practical utility of such dynamic programming algorithms. We have developed software to construct tree decompositions using various heuristics and have created a fast, memory-efficient dynamic programming implementation for solving maximum weighted independent set. We describe our software and the algorithms we have implemented, focusing on memory saving techniques for the dynamic programming. We compare the running time and memory usage of our implementation with other techniques for solving maximum weighted independent set, including a commercial integer programming solver and a semi-definite programming solver. Our results indicate that it is possible to solve some instances where the underlying decomposition has width much larger than suggested by the literature. For certain types of problems, our dynamic programming code runs several times faster than these other methods.
Optimal power system management via mixed integer dynamic programming
Energy Technology Data Exchange (ETDEWEB)
Kwatny, H.G.; Mensah, E. [Drexel Univ., Philadelphia, PA (United States). Dept. of Mechanical Engineering and Mechanics; Niebur, D. [Drexel Univ., Philadelphia, PA (United States). Dept. of Electrical and Computer Engineering; Teolis, C. [Techno-Sciences Inc., Lanham, MD (United States)
2006-07-01
Power systems are comprised of continuous and discrete acting components and subsystems. This paper discussed a logical specification that was used to define the transition dynamics of the discrete subsystem. It also presented a computational tool that reduced the logical specification to a set of inequalities as well as the use of the transformed model in a dynamic programming approach to the design of the optimal feedback controls. An example of optimal load shedding within a power system with an aggregate induction motor and constant admittance loads was presented. Specifically, the paper outlined the problem and discussed the modeling of hybrid systems and the control problem. A solution to the optimal control problem was presented. The essential feature of the model was the characterization of the discrete subsystem in terms of a set of mixed-integer formulas. The case example showed how logical constraints involving system real variables, such as case excitation voltage, could be incorporated in the problem via transformation to mixed-integer formulas. 10 refs., 4 figs.
1991-01-01
Molecular dynamics simulations investigate local and global motion in molecules. Several parallel computing approaches have been taken to attack the most computationally expensive phase of molecular simulations, the evaluation of long range interactions. This paper develops a straightforward but effective algorithm for molecular dynamics simulations using the machine-independent parallel programming language, Linda. The algorithm was run both on a shared memory parallel computer and on a netw...
Solving bilevel programs with the KKT-approach
Bouza Allende, Gemayqzel; Still, Georg
2013-01-01
Bilevel programs (BL) form a special class of optimization problems. They appear in many models in economics, game theory and mathematical physics. BL programs show a more complicated structure than standard finite problems. We study the so-called KKT-approach for solving bilevel problems, where the lower level minimality condition is replaced by the KKT- or the FJ-condition. This leads to a special structured mathematical program with complementarity constraints. We analyze the KKT-approach ...
Dynamic Performance Tuning Supported by Program Specification
Directory of Open Access Journals (Sweden)
Eduardo César
2002-01-01
Full Text Available Performance analysis and tuning of parallel/distributed applications are very difficult tasks for non-expert programmers. It is necessary to provide tools that automatically carry out these tasks. These can be static tools that carry out the analysis on a post-mortem phase or can tune the application on the fly. Both kind of tools have their target applications. Static automatic analysis tools are suitable for stable application while dynamic tuning tools are more appropriate to applications with dynamic behaviour. In this paper, we describe KappaPi as an example of a static automatic performance analysis tool, and also a general environment based on parallel patterns for developing and dynamically tuning parallel/distributed applications.
An Object Oriented Approach to Semidefinite Programming
Ge, Yuzhen; Watson, Layne; Collins, Emmanuel
1998-01-01
An object-oriented design and implementation of a primal-dual algorithm for solving the semidefinite programming problem is presented. The advantages of applying the object-oriented methodology to numerical computations, in particular to an interior point algorithm for semidefinite programming, or for solving other types of linear matrix inequalities are discussed. One object-oriented design of the primal-dual algorithm and its implementation using C++ is presented. The performance of the ...
Dynamic Learning Objects to Teach Java Programming Language
Narasimhamurthy, Uma; Al Shawkani, Khuloud
2010-01-01
This article describes a model for teaching Java Programming Language through Dynamic Learning Objects. The design of the learning objects was based on effective learning design principles to help students learn the complex topic of Java Programming. Visualization was also used to facilitate the learning of the concepts. (Contains 1 figure and 2…
Dynamic Learning Objects to Teach Java Programming Language
Narasimhamurthy, Uma; Al Shawkani, Khuloud
2010-01-01
This article describes a model for teaching Java Programming Language through Dynamic Learning Objects. The design of the learning objects was based on effective learning design principles to help students learn the complex topic of Java Programming. Visualization was also used to facilitate the learning of the concepts. (Contains 1 figure and 2…
A Systematic Survey of Program Comprehension through Dynamic Analysis
Cornelissen, B.; Zaidman, A.; Van Deursen, A.; Moonen, L.; Koschke, R.
2009-01-01
Program comprehension is an important activity in software maintenance, as software must be sufficiently understood before it can be properly modified. The study of a program's execution, known as dynamic analysis, has become a common technique in this respect and has received substantial attention
A shape dynamical approach to holographic renormalization
Energy Technology Data Exchange (ETDEWEB)
Gomes, Henrique [University of California at Davis, Davis, CA (United States); Gryb, Sean [Utrecht University, Institute for Theoretical Physics, Utrecht (Netherlands); Radboud University Nijmegen, Institute for Mathematics, Astrophysics and Particle Physics, Nijmegen (Netherlands); Koslowski, Tim [University of New Brunswick, Fredericton, NB (Canada); Mercati, Flavio; Smolin, Lee [Perimeter Institute for Theoretical Physics, Waterloo, ON (Canada)
2015-01-01
We provide a bottom-up argument to derive some known results from holographic renormalization using the classical bulk-bulk equivalence of General Relativity and Shape Dynamics, a theory with spatial conformal (Weyl) invariance. The purpose of this paper is twofold: (1) to advertise the simple classical mechanism, trading off gauge symmetries, that underlies the bulk-bulk equivalence of General Relativity and Shape Dynamics to readers interested in dualities of the type of AdS/conformal field theory (CFT); and (2) to highlight that this mechanism can be used to explain certain results of holographic renormalization, providing an alternative to the AdS/CFT conjecture for these cases. To make contact with the usual semiclassical AdS/CFT correspondence, we provide, in addition, a heuristic argument that makes it plausible that the classical equivalence between General Relativity and Shape Dynamics turns into a duality between radial evolution in gravity and the renormalization group flow of a CFT. We believe that Shape Dynamics provides a new perspective on gravity by giving conformal structure a primary role within the theory. It is hoped that this work provides the first steps toward understanding what this new perspective may be able to teach us about holographic dualities. (orig.)
Programming the dynamics of biochemical reaction networks.
Simmel, Friedrich C
2013-01-22
The development of complex self-organizing molecular systems for future nanotechnology requires not only robust formation of molecular structures by self-assembly but also precise control over their temporal dynamics. As an exquisite example of such control, in this issue of ACS Nano, Fujii and Rondelez demonstrate a particularly compact realization of a molecular "predator-prey" ecosystem consisting of only three DNA species and three enzymes. The system displays pronounced oscillatory dynamics, in good agreement with the predictions of a simple theoretical model. Moreover, its considerable modularity also allows for ecological studies of competition and cooperation within molecular networks.
Dynamic Programming Method for Impulsive Control Problems
Balkew, Teshome Mogessie
2015-01-01
In many control systems changes in the dynamics occur unexpectedly or are applied by a controller as needed. The time at which a controller implements changes is not necessarily known a priori. For example, many manufacturing systems and flight operations have complicated control systems, and changes in the control systems may be automatically…
A novel approach to dynamic livelihood clustering
DEFF Research Database (Denmark)
Walelign, Solomon Zena; Pouliot, Mariéve; Larsen, Helle Overgaard
Rural households are heterogeneous: different socio-economic characteristics and asset endowments dictate their engagement with different livelihood activities resulting in different livelihood outcomes. Poverty reduction policies should consider this. Using a unique environmentally augmented three...... households accumulated assets and capital through farming, petty trading and migratory work. The applied approach of combining income and assets better distinguishes the identified livelihood strategies compared to both the income and the asset approach and allows targeting of interventions towards specific...
Quantum electron-vibrational dynamics at finite temperature: Thermo field dynamics approach
Borrelli, Raffaele; Gelin, Maxim F.
2016-12-01
Quantum electron-vibrational dynamics in molecular systems at finite temperature is described using an approach based on the thermo field dynamics theory. This formulation treats temperature effects in the Hilbert space without introducing the Liouville space. A comparison with the theoretically equivalent density matrix formulation shows the key numerical advantages of the present approach. The solution of thermo field dynamics equations with a novel technique for the propagation of tensor trains (matrix product states) is discussed. Numerical applications to model spin-boson systems show that the present approach is a promising tool for the description of quantum dynamics of complex molecular systems at finite temperature.
A multibody dynamic approach for colliding particles
van Staeyen, K.; Tijskens, E.; Ramon, H.
2003-09-01
The dynamics of systems of moving particles in engineering applications is rapidly gaining interest as the incentive to control and optimize granular flow systems increases. Increasing availability of computing power has rendered the in silico study of large assemblies of discrete particles in near-realistic systems feasible. Generally, the governing equations for systems of non-adhesive discrete particles are derived from Newton's equation of motion with the basic assumption that the normal and tangential forces arising between two impacting particles can be independently derived from the virtual overlap of the particles and the tangential displacement of the initial contact points. In this study, the problem is placed in a rigorous multibody dynamics setting and a detailed comparison is made with the classical theory. An attempt has been made to treat particles and walls in a unified way.
A Review of Dynamic NURBS Approach
da Silva, Josildo Pereira; Giraldi, Gilson A
2013-01-01
Dynamic NURBS, also called D-NURBS, is a known dynamic version of the nonuniform rational B-spline (NURBS) which integrates free-form shape representation and a physically-based model in a unified framework. More recently, computer aided design (CAD) and finite element (FEM) community realized the need to unify CAD and FEM descriptions which motivates a review of D-NURBS concepts. Therefore, in this paper we describe D-NURBS theory in the context of 1D shape deformations. We start with a revision of NURBS for parametric representation of curve spaces. Then, the Lagrangian mechanics is introduced in order to complete the theoretical background. Next, the D-NURBS framework for 1D curve spaces is presented as well as some details about constraints and numerical implementations. In the experimental results, we focus on parameters choice and computational cost.
Modelling of windmill induction generators in dynamic simulation programs
DEFF Research Database (Denmark)
Akhmatov, Vladislav; Knudsen, Hans
1999-01-01
. It is shown that it is possible to include a transient model in dynamic stability programs and thus obtain correct results also in dynamic stability programs. A mechanical model of the shaft system has also been included in the generator model...... with and without a model of the mechanical shaft. The reason for the discrepancies are explained, and it is shown that the phenomenon is due partly to the presence of DC offset currents in the induction machine stator, and partly to the mechanical shaft system of the wind turbine and the generator rotor......For AC networks with large amounts of induction generators-in case of e.g. windmills-the paper demonstrates a significant discrepancy in the simulated voltage recovery after faults in weak networks, when comparing result obtained with dynamic stability programs and transient programs, respectively...
SLAM - Based Approach to Dynamic Ship Positioning
Directory of Open Access Journals (Sweden)
Krzysztof Wrobel
2014-03-01
Full Text Available Dynamically positioned vessels, used by offshore industry, use not only satellite navigation but also different positioning systems, often referred to as reference' systems. Most of them use multiple technical devices located outside the vessel which creates some problems with their accessibility and performance. In this paper, a basic concept of reference system independent from any external device is presented, basing on hydroacoustics and Simultaneous Localization and Mapping (SLAM method. Theoretical analysis of its operability is also performed.
Uncertain dynamical systems: A differential game approach
Gutman, S.
1976-01-01
A class of dynamical systems in a conflict situation is formulated and discussed, and the formulation is applied to the study of an important class of systems in the presence of uncertainty. The uncertainty is deterministic and the only assumption is that its value belongs to a known compact set. Asymptotic stability is fully discussed with application to variable structure and model reference control systems.
Time Series Forecasting: A Nonlinear Dynamics Approach
Sello, Stefano
1999-01-01
The problem of prediction of a given time series is examined on the basis of recent nonlinear dynamics theories. Particular attention is devoted to forecast the amplitude and phase of one of the most common solar indicator activity, the international monthly smoothed sunspot number. It is well known that the solar cycle is very difficult to predict due to the intrinsic complexity of the related time behaviour and to the lack of a succesful quantitative theoretical model of the Sun magnetic cy...
Productive Parallel Programming: The PCN Approach
Directory of Open Access Journals (Sweden)
Ian Foster
1992-01-01
Full Text Available We describe the PCN programming system, focusing on those features designed to improve the productivity of scientists and engineers using parallel supercomputers. These features include a simple notation for the concise specification of concurrent algorithms, the ability to incorporate existing Fortran and C code into parallel applications, facilities for reusing parallel program components, a portable toolkit that allows applications to be developed on a workstation or small parallel computer and run unchanged on supercomputers, and integrated debugging and performance analysis tools. We survey representative scientific applications and identify problem classes for which PCN has proved particularly useful.
Evolutionary programming for goal-driven dynamic planning
Vaccaro, James M.; Guest, Clark C.; Ross, David O.
2002-03-01
Many complex artificial intelligence (IA) problems are goal- driven in nature and the opportunity exists to realize the benefits of a goal-oriented solution. In many cases, such as in command and control, a goal-oriented approach may be the only option. One of many appropriate applications for such an approach is War Gaming. War Gaming is an important tool for command and control because it provides a set of alternative courses of actions so that military leaders can contemplate their next move in the battlefield. For instance, when making decisions that save lives, it is necessary to completely understand the consequences of a given order. A goal-oriented approach provides a slowly evolving tractably reasoned solution that inherently follows one of the principles of war: namely concentration on the objective. Future decision-making will depend not only on the battlefield, but also on a virtual world where military leaders can wage wars and determine their options by playing computer war games much like the real world. The problem with these games is that the built-in AI does not learn nor adapt and many times cheats, because the intelligent player has access to all the information, while the user has access to limited information provided on a display. These games are written for the purpose of entertainment and actions are calculated a priori and off-line, and are made prior or during their development. With these games getting more sophisticated in structure and less domain specific in scope, there needs to be a more general intelligent player that can adapt and learn in case the battlefield situations or the rules of engagement change. One such war game that might be considered is Risk. Risk incorporates the principles of war, is a top-down scalable model, and provides a good application for testing a variety of goal- oriented AI approaches. By integrating a goal-oriented hybrid approach, one can develop a program that plays the Risk game effectively and move
Granular contact dynamics using mathematical programming methods
DEFF Research Database (Denmark)
Krabbenhoft, K.; Lyamin, A. V.; Huang, J.
2012-01-01
A class of variational formulations for discrete element analysis of granular media is presented. These formulations lead naturally to convex mathematical programs that can be solved using standard and readily available tools. In contrast to traditional discrete element analysis, the present...
A novel genetic programming approach for epileptic seizure detection.
Bhardwaj, Arpit; Tiwari, Aruna; Krishna, Ramesh; Varma, Vishaal
2016-02-01
The human brain is a delicate mix of neurons (brain cells), electrical impulses and chemicals, known as neurotransmitters. Any damage has the potential to disrupt the workings of the brain and cause seizures. These epileptic seizures are the manifestations of epilepsy. The electroencephalograph (EEG) signals register average neuronal activity from the cerebral cortex and label changes in activity over large areas. A detailed analysis of these electroencephalograph (EEG) signals provides valuable insights into the mechanisms instigating epileptic disorders. Moreover, the detection of interictal spikes and epileptic seizures in an EEG signal plays an important role in the diagnosis of epilepsy. Automatic seizure detection methods are required, as these epileptic seizures are volatile and unpredictable. This paper deals with an automated detection of epileptic seizures in EEG signals using empirical mode decomposition (EMD) for feature extraction and proposes a novel genetic programming (GP) approach for classifying the EEG signals. Improvements in the standard GP approach are made using a Constructive Genetic Programming (CGP) in which constructive crossover and constructive subtree mutation operators are introduced. A hill climbing search is integrated in crossover and mutation operators to remove the destructive nature of these operators. A new concept of selecting the Globally Prime offspring is also presented to select the best fitness offspring generated during crossover. To decrease the time complexity of GP, a new dynamic fitness value computation (DFVC) is employed to increase the computational speed. We conducted five different sets of experiments to evaluate the performance of the proposed model in the classification of different mixtures of normal, interictal and ictal signals, and the accuracies achieved are outstandingly high. The experimental results are compared with the existing methods on same datasets, and these results affirm the potential use of
Approximate Dynamic Programming for Military Resource Allocation
2014-12-26
combinatorial optimization, the DWTA prob- lem suffers from the curses of dimensionality and optimality is often computationally intractability. As such...exponentially. These are known as dynamic programming’s curses of dimensionality [82]. Much of the existing research focuses on solution techniques for...simultaneously. • The outcomes of each stage are observed prior to the following stage (this can either be perfect knowledge or stochastic, though Hosein [47
A Collaborative Approach to International Programs.
Godbey, Galen C.; Turlington, Barbara
2002-01-01
Discusses how collaboration among institutions of higher education in developing international programs and globalizing the curriculum is becoming an effective strategy in postsecondary education. Especially for small- and medium-sized institutions, collaboration can provide the scale and quality of resources needed to sustain cost-effective,…
Optimal Control of a Fed-batch Fermentation Process by Neuro-Dynamic Programming
Directory of Open Access Journals (Sweden)
Tatiana Ilkova
2004-10-01
Full Text Available In this paper the method for optimal control of a fermentation process is presented, that is based on an approach for optimal control - Neuro-Dynamic programming. For this aim the approximation neural network is developed and the decision of the optimization problem is improved by an iteration mode founded on the Bellman equation. With this approach computing time and procedure are decreased and quality of the biomass at the end of the process is increased.
The Quantization of Gravity Dynamic Approach
Vergeles, S N
1996-01-01
On the basis of dynamic quantization method we build in this paper a new mathematically correct quantization scheme of gravity. In the frame of this scheme we develop a canonical formalism in tetrad-connection variables in 4-D theory of pure gravity. In this formalism the regularized quantized fields corresponding to the classical tetrad and connection fields are constructed. It is shown, that the regularized fields satisfy to general covariant equations of motion, which have the classical form. In order to solve these equations the iterative procedure is offered.
A population dynamics approach to biological aging
de Almeida, R. M. C.
A dynamical model for aging in biological population is discussed where asexual reproduction is considered. The maximum life span is inherited from parent to offspring with some random mutations described by a transition matrix, and the fertile period begins at a defined age R. The intra species competition is modeled through a Verhulst-like factor. Discrete time evolution equations are iterated and the transient and asymptotic solutions are obtained. When only bad mutations are taken into account, the stationary solutions are obtained analytically. The results are applied to the Penna model.
Cosmic infinity: A dynamical system approach
Bouhmadi-López, Mariam; Morais, João; Silva, César M
2016-01-01
Dynamical system techniques are extremely useful to study cosmology. It turns out that in most of the cases, we deal with finite isolated fixed points corresponding to a given cosmological epoch. However, it is equally important to analyse the asymptotic behaviour of the universe. On this paper, we show how this can be carried out for 3-forms model. In fact, we show that there are fixed points at infinity mainly by introducing appropriate compactifications and defining a new time variable that washes away any potential divergence of the system. The richness of 3-form models allows us as well to identify normally hyperbolic non-isolated fixed points.
Testing Object-Oriented Programs using Dynamic Aspects and Non-Determinism
DEFF Research Database (Denmark)
Achenbach, Michael; Ostermann, Klaus
2010-01-01
without parameterization or generation of tests. It also eases modelling naturally non-deterministic program features like IO or multi-threading in integration tests. Dynamic AOP facilitates powerful design adaptations without exposing test features, keeping the scope of these adaptations local to each...... test. We also combine non-determinism and dynamic aspects in a new approach to testing multi-threaded programs using co-routines.......The implementation of unit tests with mock objects and stubs often involves substantial manual work. Stubbed methods return simple default values, therefore variations of these values require separate test cases. The integration of mock objects often requires more infrastructure code and design...
A Program Recognition and Auto-Testing Approach
Directory of Open Access Journals (Sweden)
Wen C. Pai
2003-06-01
Full Text Available The goals of the software testing are to assess and improve the quality of the software. An important problem in software testing is to determine whether a program has been tested enough with a testing criterion. To raise a technology to reconstruct the program structure and generating test data automatically will help software developers to improve software quality efficiently. Program recognition and transformation is a technology that can help maintainers to recover the programs' structure and consequently make software testing properly. In this paper, a methodology to follow the logic of a program and transform to the original program graph is proposed. An approach to derive testing paths automatically for a program to test every blocks of the program is provided. A real example is presented to illustrate and prove that the methodology is practicable. The proposed methodology allows developers to recover the programs' design and makes software maintenance properly.
System identification based approach to dynamic weighing revisited
Niedźwiecki, Maciej; Meller, Michał; Pietrzak, Przemysław
2016-12-01
Dynamic weighing, i.e., weighing of objects in motion, without stopping them on the weighing platform, allows one to increase the rate of operation of automatic weighing systems, used in industrial production processes, without compromising their accuracy. Since the classical identification-based approach to dynamic weighing, based on the second-order mass-spring-damper model of the weighing system, does not yield satisfactory results when applied to conveyor belt type checkweighers, several extensions of this technique are examined. Experiments confirm that when appropriately modified the identification-based approach becomes a reliable tool for dynamic mass measurement in checkweighers.
Dynamic Pricing Criteria in Linear Programming
1988-07-01
Dantzig, M.A.H. Dempster and M. Kallio, eds.), pp. 631- 662, IIASA , Laxenburg, Austria. [23] Karmarkar, N. (1984). A new polynomial-time algorithm for...simplex method, in Large Scale Linear Programming (G.B. Dantzig, M.A.H. Dempster and M. Kallio, eds.), pp. 55-66, IIASA , Laxenburg, Austria. [39] Perold...M.J. Kallio, eds.), pp. 67-96, IIASA , Laxenburg, Austria. [40] Pyle, L.D. (1987). Generalizations of the simplex algorithm, Department of Compvter
The application of dynamic programming in production planning
Wu, Run
2017-05-01
Nowadays, with the popularity of the computers, various industries and fields are widely applying computer information technology, which brings about huge demand for a variety of application software. In order to develop software meeting various needs with most economical cost and best quality, programmers must design efficient algorithms. A superior algorithm can not only soul up one thing, but also maximize the benefits and generate the smallest overhead. As one of the common algorithms, dynamic programming algorithms are used to solving problems with some sort of optimal properties. When solving problems with a large amount of sub-problems that needs repetitive calculations, the ordinary sub-recursive method requires to consume exponential time, and dynamic programming algorithm can reduce the time complexity of the algorithm to the polynomial level, according to which we can conclude that dynamic programming algorithm is a very efficient compared to other algorithms reducing the computational complexity and enriching the computational results. In this paper, we expound the concept, basic elements, properties, core, solving steps and difficulties of the dynamic programming algorithm besides, establish the dynamic programming model of the production planning problem.
A molecular dynamics approach to barrodiffusion
Cooley, James; Marciante, Mathieu; Murillo, Michael
2016-10-01
Unexpected phenomena in the reaction rates for Inertial Confinement Fusion (ICF) capsules have led to a renewed interest in the thermo-dynamically driven diffusion process for the past 10 years, often described collectively as barodiffusion. In the current context, barodiffusion would manifest as a process that separates ions of differing mass and charge ratios due to pressure and temperature gradients set-up through shock structures in the capsule core. Barrodiffusion includes additional mass transfer terms that account for the irreversible transport of species due to gradients in the system, both thermodynamic and electric e.g, i = - ρD [ ∇c +kp ∇ln(pi) +kT(i) ∇ln(Ti) +kt(e) ∇ln(Te) +eke/Ti ∇ϕ ] . Several groups have attacked this phenomena using continuum scale models and supplemented with kinetic theory to derive coefficients for the different diffusion terms based on assumptions about the collisional processes. In contrast, we have applied a molecular dynamics (MD) simulation to this system to gain a first-principle understanding of the rate kinetics and to assess the accuracy of the differin
Time Series Forecasting A Nonlinear Dynamics Approach
Sello, S
1999-01-01
The problem of prediction of a given time series is examined on the basis of recent nonlinear dynamics theories. Particular attention is devoted to forecast the amplitude and phase of one of the most common solar indicator activity, the international monthly smoothed sunspot number. It is well known that the solar cycle is very difficult to predict due to the intrinsic complexity of the related time behaviour and to the lack of a succesful quantitative theoretical model of the Sun magnetic cycle. Starting from a previous recent work, we checked the reliability and accuracy of a forecasting model based on concepts of nonlinear dynamical systems applied to experimental time series, such as embedding phase space,Lyapunov spectrum,chaotic behaviour. The model is based on a locally hypothesis of the behaviour on the embedding space, utilizing an optimal number k of neighbour vectors to predict the future evolution of the current point with the set of characteristic parameters determined by several previous paramet...
Sediment Analysis Using a Structured Programming Approach
Directory of Open Access Journals (Sweden)
Daniela Arias-Madrid
2012-12-01
Full Text Available This paper presents an algorithm designed for the analysis of a sedimentary sample of unconsolidated material and seeks to identify very quickly the main features that occur in a sediment and thus classify them fast and efficiently. For this purpose, it requires that the weight of each particle size to be entered in the program and using the method of Moments, which is based on four equations representing the mean, standard deviation, skewness and kurtosis, is found the attributes of the sample in few seconds. With the program these calculations are performed in an effective and more accurately way, obtaining also the explanations of the results of the features such as grain size, sorting, symmetry and origin, which helps to improve the study of sediments and in general the study of sedimentary rocks.
Dynamic Test Generation for Large Binary Programs
2009-11-12
Patrice Godefroid, Dennis Jeffries, and Adam Kiezun. The SAGE system builds on the iDNA/Time Travel Debugging and Nirvana infrastructure produced by... Nirvana [7] or Valgrind [74] (Catchconv is an example of the latter approach [70].) SAGE adopts offline trace-based constraint generation for two reasons
A Hybrid Data Association Approach for SLAM in Dynamic Environments
Directory of Open Access Journals (Sweden)
Baifan Chen
2013-02-01
Full Text Available Data association is critical for Simultaneous Localization and Mapping (SLAM. In a real environment, dynamic obstacles will lead to false data associations which compromise SLAM results. This paper presents a simple and effective data association method for SLAM in dynamic environments. A hybrid approach of data association based on local maps by combining ICNN and JCBB algorithms is used initially. Secondly, we set a judging condition of outlier features in association assumptions and then the static and dynamic features are detected according to spatial and temporal difference. Finally, association assumptions are updated by filtering out the dynamic features. Simulations and experimental results show that this method is feasible.
A Survey of Biometric keystroke Dynamics: Approaches, Security and Challenges
Directory of Open Access Journals (Sweden)
Mrs. D. Shanmugapriya
2009-09-01
Full Text Available Biometrics technologies are gaining popularity today since they provide more reliable and efficient means of authentication and verification. Keystroke Dynamics is one of the famous biometric technologies, which will try to identify the authenticity of a user when the user is working via a keyboard. The authentication process is done by observing the change in the typing pattern of the user. A comprehensive survey of the existing keystroke dynamics methods, metrics, different approaches are given in this study. This paper also discusses about the various security issues and challenges faced by keystroke dynamics..Keywords- Biometris; Keystroke Dynamics; computer Security; Information Security; User Authentication.
Elastic Multibody Dynamics A Direct Ritz Approach
Bremer, H
2008-01-01
This textbook is an introduction to and exploration of a number of core topics in the field of applied mechanics: On the basis of Lagrange's Principle, a Central Equation of Dynamics is presented which yields a unified view on existing methods. From these, the Projection Equation is selected for the derivation of the motion equations of holonomic and of non-holonomic systems. The method is applied to rigid multibody systems where the rigid body is defined such that, by relaxation of the rigidity constraints, one can directly proceed to elastic bodies. A decomposition into subsystems leads to a minimal representation and to a recursive representation, respectively, of the equations of motion. Applied to elastic multibody systems one obtains, along with the use of spatial operators, a straight-on procedure for the interconnected partial and ordinary differential equations and the corresponding boundary conditions. The spatial operators are eventually applied to a RITZ series for approximation. The resulting equ...
A Chaotic Approach to Market Dynamics
Pellicer-Lostao, Carmen
2010-01-01
Economy is demanding new models, able to understand and predict the evolution of markets. To this respect, Econophysics is offering models of markets as complex systems, such as the gas-like model, able to predict money distributions observed in real economies. However, this model reveals some technical hitches to explain the power law (Pareto) distribution, observed in individuals with high incomes. Here, non linear dynamics is introduced in the gas-like model. The results obtained demonstrate that a chaotic gas-like model can reproduce the two money distributions observed in real economies (Exponential and Pareto). Moreover, it is able to control the transition between them. This may give some insight of the micro-level causes that originate unfair distributions of money in a global society. Ultimately, the chaotic model makes obvious the inherent instability of asymmetric scenarios, where sinks of wealth appear in the market and doom it to complete inequality.
Optimal Input Design for Aircraft Parameter Estimation using Dynamic Programming Principles
Morelli, Eugene A.; Klein, Vladislav
1990-01-01
A new technique was developed for designing optimal flight test inputs for aircraft parameter estimation experiments. The principles of dynamic programming were used for the design in the time domain. This approach made it possible to include realistic practical constraints on the input and output variables. A description of the new approach is presented, followed by an example for a multiple input linear model describing the lateral dynamics of a fighter aircraft. The optimal input designs produced by the new technique demonstrated improved quality and expanded capability relative to the conventional multiple input design method.
A New Approach to Recursive Programs
1975-12-01
condtions. The main part of this program is the functional f IF]: if «-a then y tlit F (F ««.y-l I .F (K-1 ty») , in which the symbol F is...involvec n the procese of proving propertiee of fixedpointei A function f , a domain 0 , and a deeired property Q Any one of these...holds. Thia method can be justified by the following argument! By part (t), any fixedpoint fcS haa proparty 0.(0
A New Approach to Solving Nonlinear Programming
Institute of Scientific and Technical Information of China (English)
SHEN Jie; CHEN Ling
2002-01-01
A method for solving nonlinear programming using genetic algorithm is presented. In the operations of crossover and mutation in each generation, to ensure the new solutions are all feasible, we present a method in which the bounds of every variable in the solution are estimated beforehand according to the constrained conditions. For the operation of mutation, we present two methods of cube bounding and variable bounding. The experimental results are given and analyzed. They show that the method is efficient and can obtain the results in less generation.
Controller design approach based on linear programming.
Tanaka, Ryo; Shibasaki, Hiroki; Ogawa, Hiromitsu; Murakami, Takahiro; Ishida, Yoshihisa
2013-11-01
This study explains and demonstrates the design method for a control system with a load disturbance observer. Observer gains are determined by linear programming (LP) in terms of the Routh-Hurwitz stability criterion and the final-value theorem. In addition, the control model has a feedback structure, and feedback gains are determined to be the linear quadratic regulator. The simulation results confirmed that compared with the conventional method, the output estimated by our proposed method converges to a reference input faster when a load disturbance is added to a control system. In addition, we also confirmed the effectiveness of the proposed method by performing an experiment with a DC motor.
An approach for solving linear fractional programming problems ...
African Journals Online (AJOL)
An approach for solving linear fractional programming problems. ... Journal of the Nigerian Association of Mathematical Physics. Journal Home · ABOUT · Advanced Search ... Open Access DOWNLOAD FULL TEXT Subscription or Fee Access ...
Robust adaptive dynamic programming and feedback stabilization of nonlinear systems.
Jiang, Yu; Jiang, Zhong-Ping
2014-05-01
This paper studies the robust optimal control design for a class of uncertain nonlinear systems from a perspective of robust adaptive dynamic programming (RADP). The objective is to fill up a gap in the past literature of adaptive dynamic programming (ADP) where dynamic uncertainties or unmodeled dynamics are not addressed. A key strategy is to integrate tools from modern nonlinear control theory, such as the robust redesign and the backstepping techniques as well as the nonlinear small-gain theorem, with the theory of ADP. The proposed RADP methodology can be viewed as an extension of ADP to uncertain nonlinear systems. Practical learning algorithms are developed in this paper, and have been applied to the controller design problems for a jet engine and a one-machine power system.
Dynamic structural correlation via nonlinear programming techniques
Ting, T.; Ojalvo, I. U.
1988-01-01
A solution to the correlation between structural dynamic test results and finite element analyses of the same components is presented in this paper. Basically, the method can be categorized as a Levenberg-Marquardt type Gauss-Newton method which requires only the differences between FE modal analyses and test results and their first derivatives with respect to preassigned design variables. With proper variable normalization and equation scaling, the method has been made numerically better-conditioned and the inclusion of the Levenberg-Marquardt technique overcomes any remaining difficulty encountered in inverting singular or near-singular matrices. An important feature is that each iteration requires only one function evaluation along with the associated design sensitivity analysis and so the procedure is computationally efficient.
Spacecraft Dynamics and Control Program at AFRPL
Das, A.; Slimak, L. K. S.; Schloegel, W. T.
1986-01-01
A number of future DOD and NASA spacecraft such as the space based radar will be not only an order of magnitude larger in dimension than the current spacecraft, but will exhibit extreme structural flexibility with very low structural vibration frequencies. Another class of spacecraft (such as the space defense platforms) will combine large physical size with extremely precise pointing requirement. Such problems require a total departure from the traditional methods of modeling and control system design of spacecraft where structural flexibility is treated as a secondary effect. With these problems in mind, the Air Force Rocket Propulsion Laboratory (AFRPL) initiated research to develop dynamics and control technology so as to enable the future large space structures (LSS). AFRPL's effort in this area can be subdivided into the following three overlapping areas: (1) ground experiments, (2) spacecraft modeling and control, and (3) sensors and actuators. Both the in-house and contractual efforts of the AFRPL in LSS are summarized.
A general approach to belief change in answer set programming
Delgrande, James; Tompits, Hans; Woltran, Stefan
2009-01-01
We address the problem of belief change in (nonmonotonic) logic programming under answer set semantics. Unlike previous approaches to belief change in logic programming, our formal techniques are analogous to those of distance-based belief revision in propositional logic. In developing our results, we build upon the model theory of logic programs furnished by SE models. Since SE models provide a formal, monotonic characterisation of logic programs, we can adapt techniques from the area of belief revision to belief change in logic programs. We introduce methods for revising and merging logic programs, respectively. For the former, we study both subset-based revision as well as cardinality-based revision, and we show that they satisfy the majority of the AGM postulates for revision. For merging, we consider operators following arbitration merging and IC merging, respectively. We also present encodings for computing the revision as well as the merging of logic programs within the same logic programming framework...
Dynamical-systems approach to localised turbulence in pipe flow
Ritter, Paul; Avila, Marc
2015-01-01
Turbulent-laminar patterns are ubiquitous near transition in wall-bounded shear flows. Despite recent progress in describing their dynamics in analogy to nonequilibrium phase transitions, there is no theory explaining their emergence. Dynamical-system approaches suggest that invariant solutions to the Navier-Stokes equations, such as traveling waves and relative periodic orbits in pipe flow, act as building blocks of the disordered dynamics. While recent studies have shown how transient chaos arises from such solutions, the ensuing dynamics lacks the strong fluctuations in size, shape and speed of the turbulent spots observed in experiments. We here show that chaotic spots with distinct dynamical and kinematic properties merge in phase space and give rise to the enhanced spatiotemporal patterns observed in pipe flow. This paves the way for a dynamical-system foundation to the phenomenogloy of turbulent-laminar patterns in wall-bounded extended shear flows.
Eucb: A C++ program for molecular dynamics trajectory analysis
Tsoulos, Ioannis G.; Stavrakoudis, Athanassios
2011-03-01
Eucb is a standalone program for geometrical analysis of molecular dynamics trajectories of protein systems. The program is written in GNU C++ and it can be installed in any operating system running a C++ compiler. The program performs its analytical tasks based on user supplied keywords. The source code is freely available from http://stavrakoudis.econ.uoi.gr/eucb under LGPL 3 license. Program summaryProgram title:Eucb Catalogue identifier: AEIC_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEIC_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 31 169 No. of bytes in distributed program, including test data, etc.: 297 364 Distribution format: tar.gz Programming language: GNU C++ Computer: The tool is designed and tested on GNU/Linux systems Operating system: Unix/Linux systems RAM: 2 MB Supplementary material: Sample data files are available Classification: 3 Nature of problem: Analysis of molecular dynamics trajectories. Solution method: The program finds all possible interactions according to input files and the user instructions. Then it reads all the trajectory frames and finds those frames in which these interactions occur, under certain geometrical criteria. This is a blind search, without a priori knowledge if a certain interaction occurs or not. The program exports time series of these quantities (distance, angles, etc.) and appropriate descriptive statistics. Running time: Depends on the input data and the required options.
Research on teacher education programs: logic model approach.
Newton, Xiaoxia A; Poon, Rebecca C; Nunes, Nicole L; Stone, Elisa M
2013-02-01
Teacher education programs in the United States face increasing pressure to demonstrate their effectiveness through pupils' learning gains in classrooms where program graduates teach. The link between teacher candidates' learning in teacher education programs and pupils' learning in K-12 classrooms implicit in the policy discourse suggests a one-to-one correspondence. However, the logical steps leading from what teacher candidates have learned in their programs to what they are doing in classrooms that may contribute to their pupils' learning are anything but straightforward. In this paper, we argue that the logic model approach from scholarship on evaluation can enhance research on teacher education by making explicit the logical links between program processes and intended outcomes. We demonstrate the usefulness of the logic model approach through our own work on designing a longitudinal study that focuses on examining the process and impact of an undergraduate mathematics and science teacher education program.
Approximate dynamic programming solving the curses of dimensionality
Powell, Warren B
2007-01-01
Warren B. Powell, PhD, is Professor of Operations Research and Financial Engineering at Princeton University, where he is founder and Director of CASTLE Laboratory, a research unit that works with industrial partners to test new ideas found in operations research. The recipient of the 2004 INFORMS Fellow Award, Dr. Powell has authored over 100 refereed publications on stochastic optimization, approximate dynamic programming, and dynamic resource management.
Program participation, labor force dynamics, and accepted wage rates
DEFF Research Database (Denmark)
Munch, Jakob Roland; Skipper, Lars
2008-01-01
We apply a recently suggested econometric approach to measure the effects of active labor market programs on employment, unemployment, and wage histories among participants. We find that participation in most of these training programs produces an initial locking-in effect and for some even a lower...... subpopulations. These longer spells of employment come at a cost of lower accepted hourly wage rates...
Developing Dynamic Virtual Environments Using Hierarchical, Tree-Structured Approach
Directory of Open Access Journals (Sweden)
Wan Mohd Rizhan Wan Idris
2011-05-01
Full Text Available Virtual reality (VR has been utilized in various applications such as in architecture, medicine, advertisement, business, entertainment, and education. In the world of simulation, VR software allows users to visualize, manipulate and interact with the computers and complex data. However, developing VR environments is costly and expensive. Highly-technical persons are needed to create the virtual objects from scratch. Once a virtual system is created, managing and modifying it creates further problems. There is a need for non-technical users to be able to create and modify their own virtual environments. This paper discusses a systematic technique to develop dynamic virtual environments and to manage virtual objects in their virtual environment. The technique is called hierarchical, tree-structured approach. To implement the technique, object-oriented programming language was used such as Java, Java 3D and Java Swing. For the usability and performance of the technique, a virtual environment has been created to become as case study. The tool has been perceived as an easy tool to use, especially for an environment in education.
DEVELOPING DYNAMIC VIRTUAL ENVIRONMENTS USING HIERARCHICAL, TREE-STRUCTURED APPROACH
Directory of Open Access Journals (Sweden)
Wan Mohd Rizhan Wan Idris
2015-10-01
Full Text Available Virtual reality (VR has been utilized in various applications such as in architecture, medicine, advertisement, business, entertainment, and education. In the world of simulation, VR software allows users to visualize, manipulate and interact with the computers and complex data. However, developing VR environments is costly and expensive. Highly-technical persons are needed to create the virtual objects from scratch. Once a virtual system is created, managing and modifying it creates further problems. There is a need for non-technical users to be able to create and modify their own virtual environments. This paper discusses a systematic technique to develop dynamic virtual environments and to manage virtual objects in their virtual environment. The technique is called hierarchical, tree-structured approach. To implement the technique, object-oriented programming language was used such as Java, Java 3D and Java Swing. For the usability and performance of the technique, a virtual environment has been created to become as case study. The tool has been perceived as an easy tool to use, especially for an environment in education.
Developing molecular dynamics simulation codes using mixed language programming
Energy Technology Data Exchange (ETDEWEB)
DeBoni, T.; Feo, J.T. [Lawrence Livermore National Lab., CA (United States); Caffey, H.; Hausheer, F. [BioNumerik Pharmaceuticals, Inc., San Antonio, TX (United States)
1994-05-01
We describe our experiences parallelizing a large-scale scientific application to model systems of discrete particles. We describe the approach and tasks undertaken to parallelize this application using two different programming paradigms: imperative and functional. The objectives of both exercises were to maximize performance, parallelism and portability, and to minimize program development costs. We believe this study reveals an important relationship between conventional and novel parallel programming paradigms, and identifies important attributes that novel paradigms must have to gain wide acceptance.
Vehicle Dynamics Approach to Driver Warning
Directory of Open Access Journals (Sweden)
Youssef A. Ghoneim
2013-01-01
Full Text Available This paper discusses a concept for enhanced active safety by introducing a driver warning system based on vehicle dynamics that predicts a potential loss of control condition prior to stability control activation. This real-time warning algorithm builds on available technologies such as the Electronic Stability Control (ESC. The driver warning system computes several indices based on yaw rate, side-slip velocity, and vehicle understeer using ESC sensor suite. An arbitrator block arbitrates between the different indices and determines the status index of the driving vehicle. The status index is compared to predetermined stability levels which correspond to high and low stability levels. If the index exceeds the high stability level, a warning signal (haptic, acoustic, or visual is issued to alert the driver of a potential loss of control and ESC activation. This alert will remain in effect until the index is less than the low stability level at which time the warning signal will be terminated. A vehicle speed advisory algorithm is integrated with the warning algorithm to provide a desired vehicle speed of a vehicle traveling on a curve. Simulation results and vehicle tests were conducted to illustrate the effectiveness of the warning algorithm.
Fast and Cache-Oblivious Dynamic Programming with Local Dependencies
DEFF Research Database (Denmark)
Bille, Philip; Stöckel, Morten
2012-01-01
are widely used in bioinformatics to compare DNA and protein sequences. These problems can all be solved using essentially the same dynamic programming scheme over a two-dimensional matrix, where each entry depends locally on at most 3 neighboring entries. We present a simple, fast, and cache......-oblivious algorithm for this type of local dynamic programming suitable for comparing large-scale strings. Our algorithm outperforms the previous state-of-the-art solutions. Surprisingly, our new simple algorithm is competitive with a complicated, optimized, and tuned implementation of the best cache-aware algorithm...
Fast and Cache-Oblivious Dynamic Programming with Local Dependencies
DEFF Research Database (Denmark)
Bille, Philip; Stöckel, Morten
2012-01-01
are widely used in bioinformatics to compare DNA and protein sequences. These problems can all be solved using essentially the same dynamic programming scheme over a two-dimensional matrix, where each entry depends locally on at most 3 neighboring entries. We present a simple, fast, and cache......-oblivious algorithm for this type of local dynamic programming suitable for comparing large-scale strings. Our algorithm outperforms the previous state-of-the-art solutions. Surprisingly, our new simple algorithm is competitive with a complicated, optimized, and tuned implementation of the best cache-aware algorithm....... Additionally, our new algorithm generalizes the best known theoretical complexity trade-offs for the problem....
Application of dynamic programming to the correlation of paleoclimate records
Lisiecki, Lorraine E.; Lisiecki, Philip A.
2002-12-01
Signal matching is a powerful tool frequently used in paleoclimate research, but it is enormously time-consuming when performed by hand. Previously proposed automatic correlation techniques require very good initial fits to find the correct alignment of two records. A new technique presented in this paper utilizes dynamic programming to find the globally optimal alignment of two records. Geological realism is instilled in the solution through the definition of penalty functions for undesirable behavior such as unlikely changes in accumulation rate. Examples with synthetic and real data demonstrate that the dynamic programming technique produces accurate, high-resolution results with much less effort than hand tuning or preexisting automated correlation techniques.
Multi-view video color correction using dynamic programming
Institute of Scientific and Technical Information of China (English)
无
2008-01-01
Color inconsistency between views is an important problem to be solved in multi-view video systems. A multi-view video color correction method using dynamic programming is proposed. Three-dimensional histograms are constructed with sequential conditional probability in HSI color space. Then, dynamic programming is used to seek the best color mapping relation with the minimum cost path between target image histogram and source image histogram. Finally, video tracking technique is performed to correct multi-view video. Experimental results show that the proposed method can obtain better subjective and objective performance in color correction.
Hamiltonian and Lagrangian Dynamical Matrix Approaches Applied to Magnetic Nanostructures
Directory of Open Access Journals (Sweden)
Roberto Zivieri
2012-01-01
Full Text Available Two micromagnetic tools to study the spin dynamics are reviewed. Both approaches are based upon the so-called dynamical matrix method, a hybrid micromagnetic framework used to investigate the spin-wave normal modes of confined magnetic systems. The approach which was formulated first is the Hamiltonian-based dynamical matrix method. This method, used to investigate dynamic magnetic properties of conservative systems, was originally developed for studying spin excitations in isolated magnetic nanoparticles and it has been recently generalized to study the dynamics of periodic magnetic nanoparticles. The other one, the Lagrangian-based dynamical matrix method, was formulated as an extension of the previous one in order to include also dissipative effects. Such dissipative phenomena are associated not only to intrinsic but also to extrinsic damping caused by injection of a spin current in the form of spin-transfer torque. This method is very accurate in identifying spin modes that become unstable under the action of a spin current. The analytical development of the system of the linearized equations of motion leads to a complex generalized Hermitian eigenvalue problem in the Hamiltonian dynamical matrix method and to a non-Hermitian one in the Lagrangian approach. In both cases, such systems have to be solved numerically.
Evaluation of Slum Upgrading Programs: Literature Review and Methodological Approaches
José Brakarz; Laura Jaitman
2013-01-01
This technical note analyzes the methodologies used to evaluate neighborhood upgrading programs, describes their results, and suggests approaches for future evaluations. Local and central governments are increasingly utilizing slum or neighborhood upgrading programs to deal with the multiple problems of urban poverty. These programs employ a methodology of integral interventions, combining of both infrastructure works and social services targeted to specific neighborhoods. Due to this variety...
Cost and Earning Dynamism: The Cointegration Approach
Directory of Open Access Journals (Sweden)
Kehinde James Sunday
2013-05-01
Full Text Available The study examine the existence of a long run equilibrium between various cost variables and earning and the existence of cost variables stability of the in the firm. Secondary data from the financial reports of Cadbury Nigeria plc covering 2001 to 2010 was adopted for the study. The Augmented Dickey Fuller (ADF unit root technique was used for the stationary test while the Engle-Granger approach was adopted for the cointegration test. The study reveals that long run relationships exist between the variables and the long run stability relationships exist between the variables, however, at weak significant point. It was recommended that cost management and review strategies should be adopted by the firm to strengthen the position of the firm in the industries and to put the firm in long run control of it cost and performance horizon.
F -Discrepancy for Efficient Sampling in Approximate Dynamic Programming.
Cervellera, Cristiano; Maccio, Danilo
2016-07-01
In this paper, we address the problem of generating efficient state sample points for the solution of continuous-state finite-horizon Markovian decision problems through approximate dynamic programming. It is known that the selection of sampling points at which the value function is observed is a key factor when such function is approximated by a model based on a finite number of evaluations. A standard approach consists in generating these points through a random or deterministic procedure, aiming at a balanced covering of the state space. Yet, this solution may not be efficient if the state trajectories are not uniformly distributed. Here, we propose to exploit F -discrepancy, a quantity that measures how closely a set of random points represents a probability distribution, and introduce an example of an algorithm based on such concept to automatically select point sets that are efficient with respect to the underlying Markovian process. An error analysis of the approximate solution is provided, showing how the proposed algorithm enables convergence under suitable regularity hypotheses. Then, simulation results are provided concerning an inventory forecasting test problem. The tests confirm in general the important role of F -discrepancy, and show how the proposed algorithm is able to yield better results than uniform sampling, using sets even 50 times smaller.
Programming massively parallel processors a hands-on approach
Kirk, David B
2010-01-01
Programming Massively Parallel Processors discusses basic concepts about parallel programming and GPU architecture. ""Massively parallel"" refers to the use of a large number of processors to perform a set of computations in a coordinated parallel way. The book details various techniques for constructing parallel programs. It also discusses the development process, performance level, floating-point format, parallel patterns, and dynamic parallelism. The book serves as a teaching guide where parallel programming is the main topic of the course. It builds on the basics of C programming for CUDA, a parallel programming environment that is supported on NVI- DIA GPUs. Composed of 12 chapters, the book begins with basic information about the GPU as a parallel computer source. It also explains the main concepts of CUDA, data parallelism, and the importance of memory access efficiency using CUDA. The target audience of the book is graduate and undergraduate students from all science and engineering disciplines who ...
Dynamic Portfolio Strategy Using Clustering Approach
Lu, Ya-Nan; Li, Sai-Ping; Jiang, Xiong-Fei; Zhong, Li-Xin; Qiu, Tian
2017-01-01
The problem of portfolio optimization is one of the most important issues in asset management. We here propose a new dynamic portfolio strategy based on the time-varying structures of MST networks in Chinese stock markets, where the market condition is further considered when using the optimal portfolios for investment. A portfolio strategy comprises two stages: First, select the portfolios by choosing central and peripheral stocks in the selection horizon using five topological parameters, namely degree, betweenness centrality, distance on degree criterion, distance on correlation criterion and distance on distance criterion. Second, use the portfolios for investment in the investment horizon. The optimal portfolio is chosen by comparing central and peripheral portfolios under different combinations of market conditions in the selection and investment horizons. Market conditions in our paper are identified by the ratios of the number of trading days with rising index to the total number of trading days, or the sum of the amplitudes of the trading days with rising index to the sum of the amplitudes of the total trading days. We find that central portfolios outperform peripheral portfolios when the market is under a drawup condition, or when the market is stable or drawup in the selection horizon and is under a stable condition in the investment horizon. We also find that peripheral portfolios gain more than central portfolios when the market is stable in the selection horizon and is drawdown in the investment horizon. Empirical tests are carried out based on the optimal portfolio strategy. Among all possible optimal portfolio strategies based on different parameters to select portfolios and different criteria to identify market conditions, 65% of our optimal portfolio strategies outperform the random strategy for the Shanghai A-Share market while the proportion is 70% for the Shenzhen A-Share market. PMID:28129333
Dynamic Portfolio Strategy Using Clustering Approach.
Ren, Fei; Lu, Ya-Nan; Li, Sai-Ping; Jiang, Xiong-Fei; Zhong, Li-Xin; Qiu, Tian
2017-01-01
The problem of portfolio optimization is one of the most important issues in asset management. We here propose a new dynamic portfolio strategy based on the time-varying structures of MST networks in Chinese stock markets, where the market condition is further considered when using the optimal portfolios for investment. A portfolio strategy comprises two stages: First, select the portfolios by choosing central and peripheral stocks in the selection horizon using five topological parameters, namely degree, betweenness centrality, distance on degree criterion, distance on correlation criterion and distance on distance criterion. Second, use the portfolios for investment in the investment horizon. The optimal portfolio is chosen by comparing central and peripheral portfolios under different combinations of market conditions in the selection and investment horizons. Market conditions in our paper are identified by the ratios of the number of trading days with rising index to the total number of trading days, or the sum of the amplitudes of the trading days with rising index to the sum of the amplitudes of the total trading days. We find that central portfolios outperform peripheral portfolios when the market is under a drawup condition, or when the market is stable or drawup in the selection horizon and is under a stable condition in the investment horizon. We also find that peripheral portfolios gain more than central portfolios when the market is stable in the selection horizon and is drawdown in the investment horizon. Empirical tests are carried out based on the optimal portfolio strategy. Among all possible optimal portfolio strategies based on different parameters to select portfolios and different criteria to identify market conditions, 65% of our optimal portfolio strategies outperform the random strategy for the Shanghai A-Share market while the proportion is 70% for the Shenzhen A-Share market.
Letting Structure Emerge: Connectionist and Dynamical Systems Approaches to Cognition
McClelland, James L.; Botvinick, Matthew M.; Noelle, David C.; Plaut, David C.; Rogers, Timothy T.; Seidenberg, Mark S.; Smith, Linda B.
2011-01-01
Connectionist and dynamical systems approaches explain human thought, language and behavior in terms of the emergent consequences of a large number of simple non-cognitive processes. We view the entities that serve as the basis for structured probabilistic approaches as sometimes useful but often misleading abstractions that have no real basis in the actual processes that give rise to linguistic and cognitive abilities or the development of these abilities. While structured probabilistic approaches can be useful in determining what would be optimal under certain assumptions, we suggest that approaches such as the connectionist and dynamical systems approaches, which focus on explaining the mechanisms giving rise to cognition, will be essential in achieving a full understanding of cognition and development. PMID:20598626
Shifman, M A; Windemuth, A; Schulten, K; Miller, P L
1992-04-01
Molecular dynamics simulations investigate local and global motion in molecules. Several parallel computing approaches have been taken to attack the most computationally expensive phase of molecular simulations, the evaluation of long range interactions. This paper reviews these approaches and develops a straightforward but effective algorithm using the machine-independent parallel programming language, Linda. The algorithm was run both on a shared memory parallel computer and on a network of high performance Unix workstations. Performance benchmarks were performed on both systems using two proteins. This algorithm offers a portable cost-effective alternative for molecular dynamics simulations. In view of the increasing numbers of networked workstations, this approach could help make molecular dynamics simulations more easily accessible to the research community.
Beginning Java programming the object-oriented approach
Baesens, Bart; vanden Broucke, Seppe
2015-01-01
A comprehensive Java guide, with samples, exercises, case studies, and step-by-step instruction Beginning Java Programming: The Object Oriented Approach is a straightforward resource for getting started with one of the world's most enduringly popular programming languages. Based on classes taught by the authors, the book starts with the basics and gradually builds into more advanced concepts. The approach utilizes an integrated development environment that allows readers to immediately apply what they learn, and includes step-by-step instruction with plenty of sample programs. Each chapter c
Mathematical-programming approaches to test item pool design
Veldkamp, Bernard P.; van der Linden, Willem J.; Ariel, A.
2002-01-01
This paper presents an approach to item pool design that has the potential to improve on the quality of current item pools in educational and psychological testing andhence to increase both measurement precision and validity. The approach consists of the application of mathematical programming
Neurolinguistic programming: a systematic approach to change.
Steinbach, A M
1984-01-01
Neurolinguistic programming (NLP) integrates advances in cybernetics, psychophysiology, linguistics, and information services. It has been used in business, education, law, medicine and psychotherapy to alter people's responses to stimuli, so they are better able to regulate their environment and themselves. There are five steps to an effective NLP interaction. They include 1. establishing rapport; the therapist must match his verbal and non-verbal behaviors to the patient's, 2. gathering information about the patient's present problem and goals by noting his verbal patterns and non-verbal responses, 3. considering the impact that achieving the patient's goals will have on him, his work, family and friends, and retaining any positive aspects of his current situation, 4. helping the patient achieve his goals by using specific techniques to alter his responses to various stimuli, and 5. ensuring the altered responses achieved in therapy are integrated into the patient's daily life. NLP has been used to help patients with medical problems ranging from purely psychological to complex organic ones.
Liu, Ping; Li, Guodong; Liu, Xinggao
2015-09-01
Control vector parameterization (CVP) is an important approach of the engineering optimization for the industrial dynamic processes. However, its major defect, the low optimization efficiency caused by calculating the relevant differential equations in the generated nonlinear programming (NLP) problem repeatedly, limits its wide application in the engineering optimization for the industrial dynamic processes. A novel highly effective control parameterization approach, fast-CVP, is first proposed to improve the optimization efficiency for industrial dynamic processes, where the costate gradient formulae is employed and a fast approximate scheme is presented to solve the differential equations in dynamic process simulation. Three well-known engineering optimization benchmark problems of the industrial dynamic processes are demonstrated as illustration. The research results show that the proposed fast approach achieves a fine performance that at least 90% of the computation time can be saved in contrast to the traditional CVP method, which reveals the effectiveness of the proposed fast engineering optimization approach for the industrial dynamic processes. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.
A semiclassical hybrid approach to many particle quantum dynamics
Grossmann, Frank
2006-07-01
We analytically derive a correlated approach for a mixed semiclassical many particle dynamics, treating a fraction of the degrees of freedom by the multitrajectory semiclassical initial value method of Herman and Kluk [Chem. Phys. 91, 27 (1984)] while approximately treating the dynamics of the remaining degrees of freedom with fixed initial phase space variables, analogously to the thawed Gaussian wave packet dynamics of Heller [J. Chem. Phys. 62, 1544 (1975)]. A first application of this hybrid approach to the well studied Secrest-Johnson [J. Chem. Phys. 45, 4556 (1966)] model of atom-diatomic collisions is promising. Results close to the quantum ones for correlation functions as well as scattering probabilities could be gained with considerably reduced numerical effort as compared to the full semiclassical Herman-Kluk approach. Furthermore, the harmonic nature of the different degrees of freedom can be determined a posteriori by comparing results with and without the additional approximation.
Engineering system dynamics a unified graph-centered approach
Brown, Forbes T
2006-01-01
For today's students, learning to model the dynamics of complex systems is increasingly important across nearly all engineering disciplines. First published in 2001, Forbes T. Brown's Engineering System Dynamics: A Unified Graph-Centered Approach introduced students to a unique and highly successful approach to modeling system dynamics using bond graphs. Updated with nearly one-third new material, this second edition expands this approach to an even broader range of topics. What's New in the Second Edition? In addition to new material, this edition was restructured to build students' competence in traditional linear mathematical methods before they have gone too far into the modeling that still plays a pivotal role. New topics include magnetic circuits and motors including simulation with magnetic hysteresis; extensive new material on the modeling, analysis, and simulation of distributed-parameter systems; kinetic energy in thermodynamic systems; and Lagrangian and Hamiltonian methods. MATLAB(R) figures promi...
Time-dependent HF approach to SHE dynamics
Umar, A. S.; Oberacker, V. E.
2015-12-01
We employ the time-dependent Hartree-Fock (TDHF) method to study various aspects of the reactions utilized in searches for superheavy elements. These include capture cross-sections, quasifission, prediction of PCN, and other interesting dynamical quantities. We show that the microscopic TDHF approach provides an important tool to shed some light on the nuclear dynamics leading to the formation of superheavy elements.
A Supervised Approach to Windowing Detection on Dynamic Networks
2017-07-01
A supervised approach to windowing detection on dynamic networks Benjamin Fish University of Illinois at Chicago 1200 W. Harrison St. Chicago...For any stream of time-stamped edges that form a dynamic network, a necessary and important choice is the aggregation granularity that an analyst uses...to bin the data at. While this choice is often picked by hand, or left up to the tech- nology that is collecting the data, the choice can make a big
A Survey of Biometric keystroke Dynamics: Approaches, Security and Challenges
D. Shanmugapriya; Padmavathi, Dr. G.
2009-01-01
Biometrics technologies are gaining popularity today since they provide more reliable and efficient means of authentication and verification. Keystroke Dynamics is one of the famous biometric technologies, which will try to identify the authenticity of a user when the user is working via a keyboard. The authentication process is done by observing the change in the typing pattern of the user. A comprehensive survey of the existing keystroke dynamics methods, metrics, different approaches are g...
A dynamical system approach to realtime obstacle avoidance
Khansari-Zadeh, S. M.; Billard, Aude
2012-01-01
This paper presents a novel approach to real-time obstacle avoidance based on dynamical systems (DS) that ensures impenetrability of multiple convex shaped objects. The proposed method can be applied to perform obstacle avoidance in Cartesian and Joint spaces and using both autonomous and non-autonomous DS-based controllers. Obstacle avoidance proceeds by modulating the original dynamics of the controller. The modulation is parameterizable and allows to determine a safety margin and to increa...
A Constraint Embedding Approach for Complex Vehicle Suspension Dynamics
2015-04-24
2015, Barcelona, Catalonia , Spain same number of degrees of freedom as the number of independent degrees of freedom for the loops they replace...13. SUPPLEMENTARY NOTES ECCOMAS Thematic Conference on Multibody Dynamics 2015, June 29-July 2, 2015, Barcelona, Catalonia , Spain 14. ABSTRACT See...Z39-18 ECCOMAS Thematic Conference on Multibody Dynamics June 29 - July 2, 2015, Barcelona, Catalonia , Spain A Constraint Embedding Approach for
Institute of Scientific and Technical Information of China (English)
周文辉; 钟伟锋; 余荣
2015-01-01
With the rapid growing of electric vehicles (EVs), it is necessary to implement the charging control for huge number of EVs to ensure the reliability of smart grid. In this paper, a strategy of price control is proposed for EV charging. The aggregator manages EV batteries centrally and controls the EV charging demand through price. EV users change their charging demand based on the price information. However, the EV mobility is unknown in advance, which causes the inaccurate prediction of EV state and impacts the performance of price control. Thus, adaptive dynamic programming (ADP) is leveraged to achieve the optimal price policy by using online network training. Simulation results show that the proposed method is able to tune the EV charging demand close to the expected level by learning from the EV charging process and the EV mobility, which ensures the smart grid runs steadily.%针对电动汽车的充电提出一种电价控制策略。聚合管理者集中管理电动汽车的电池，并且考虑用电高峰时电网的电能供给有限，通过电价控制调整充电的需求量。采用自适应动态规划，通过在线网络训练，得到最优的电价策略。仿真结果表明，该自适应电价控制方法能够通过学习电动汽车的移动性和充电过程，从而调整实际充电需求量至期望水平，保证智能电网的稳定运行。
Modeling Dynamic Programming Problems over Sequences and Trees with Inverse Coupled Rewrite Systems
Directory of Open Access Journals (Sweden)
Robert Giegerich
2014-03-01
Full Text Available Dynamic programming is a classical algorithmic paradigm, which often allows the evaluation of a search space of exponential size in polynomial time. Recursive problem decomposition, tabulation of intermediate results for re-use, and Bellman’s Principle of Optimality are its well-understood ingredients. However, algorithms often lack abstraction and are difficult to implement, tedious to debug, and delicate to modify. The present article proposes a generic framework for specifying dynamic programming problems. This framework can handle all kinds of sequential inputs, as well as tree-structured data. Biosequence analysis, document processing, molecular structure analysis, comparison of objects assembled in a hierarchic fashion, and generally, all domains come under consideration where strings and ordered, rooted trees serve as natural data representations. The new approach introduces inverse coupled rewrite systems. They describe the solutions of combinatorial optimization problems as the inverse image of a term rewrite relation that reduces problem solutions to problem inputs. This specification leads to concise yet translucent specifications of dynamic programming algorithms. Their actual implementation may be challenging, but eventually, as we hope, it can be produced automatically. The present article demonstrates the scope of this new approach by describing a diverse set of dynamic programming problems which arise in the domain of computational biology, with examples in biosequence and molecular structure analysis.
Dynamic focusing approach to mixed-level simulation
Fall, Thomas C.
1997-06-01
The dynamic focusing approach (DFA) has been under development for several years. Its intent is to address several of the issues of mixed level simulations, particularly the aggregational issues. Though the approach requires that the system be able to be modeled within certain constraints, many systems of interest fit well within them. This approach combines a hierarchical representation of knowledge with a stochastic propagation mechanism; this provides capability to gracefully move from coarse granularity to fine granularity under user guidance. Prototype tools have been developed for engineering analysis, combat simulation and TQM process implementation. This paper gives an overview of the approach and its current status.
An Analytical Dynamics Approach to the Control of Mechanical Systems
Mylapilli, Harshavardhan
A new and novel approach to the control of nonlinear mechanical systems is presented in this study. The approach is inspired by recent results in analytical dynamics that deal with the theory of constrained motion. The control requirements on the dynamical system are viewed from an analytical dynamics perspective and the theory of constrained motion is used to recast these control requirements as constraints on the dynamical system. Explicit closed form expressions for the generalized nonlinear control forces are obtained by using the fundamental equation of mechanics. The control so obtained is optimal at each instant of time and causes the constraints to be exactly satisfied. No linearizations and/or approximations of the nonlinear dynamical system are made, and no a priori structure is imposed on the nature of nonlinear controller. Three examples dealing with highly nonlinear complex dynamical systems that are chosen from diverse areas of discrete and continuum mechanics are presented to demonstrate the control approach. The first example deals with the energy control of underactuated inhomogeneous nonlinear lattices (or chains), the second example deals with the synchronization of the motion of multiple coupled slave gyros with that of a master gyro, and the final example deals with the control of incompressible hyperelastic rubber-like thin cantilever beams. Numerical simulations accompanying these examples show the ease, simplicity and the efficacy with which the control methodology can be applied and the accuracy with which the desired control objectives can be met.
Approximate group context tree: applications to dynamic programming and dynamic choice models
Belloni, Alexandre
2011-01-01
The paper considers a variable length Markov chain model associated with a group of stationary processes that share the same context tree but potentially different conditional probabilities. We propose a new model selection and estimation method, develop oracle inequalities and model selection properties for the estimator. These results also provide conditions under which the use of the group structure can lead to improvements in the overall estimation. Our work is also motivated by two methodological applications: discrete stochastic dynamic programming and dynamic discrete choice models. We analyze the uniform estimation of the value function for dynamic programming and the uniform estimation of average dynamic marginal effects for dynamic discrete choice models accounting for possible imperfect model selection. We also derive the typical behavior of our estimator when applied to polynomially $\\beta$-mixing stochastic processes. For parametric models, we derive uniform rate of convergence for the estimation...
A statistical state dynamics approach to wall-turbulence
Farrell, Brian F; Ioannou, Petros J
2016-01-01
This paper reviews results demonstrating the benefits of studying wall-bounded shear flows using dynamics for the evolution of the statistical state of the turbulent system. The statistical state dynamics (SSD) approach used in this work employs a second order closure which isolates the interaction between the streamwise mean and the equivalent of the perturbation covariance. This closure restricts nonlinearity in the SSD to that explicitly retained in the streamwise constant mean together with nonlinear interactions between the mean and the perturbation covariance. This dynamical restriction, in which explicit perturbation-perturbation nonlinearity is removed from the perturbation equation, results in a simplified dynamics referred to as the restricted nonlinear (RNL) dynamics. RNL systems in which an ensemble of a finite number of realizations of the perturbation equation share the same mean flow provide tractable approximations to the equivalently infinite ensemble RNL system. The infinite ensemble system,...
Silicon-Neuron Design: A Dynamical Systems Approach.
Arthur, John V; Boahen, Kwabena
2011-01-01
We present an approach to design spiking silicon neurons based on dynamical systems theory. Dynamical systems theory aids in choosing the appropriate level of abstraction, prescribing a neuron model with the desired dynamics while maintaining simplicity. Further, we provide a procedure to transform the prescribed equations into subthreshold current-mode circuits. We present a circuit design example, a positive-feedback integrate-and-fire neuron, fabricated in 0.25 μm CMOS. We analyze and characterize the circuit, and demonstrate that it can be configured to exhibit desired behaviors, including spike-frequency adaptation and two forms of bursting.
A Survey of Biometric keystroke Dynamics: Approaches, Security and Challenges
Shanmugapriya, D
2009-01-01
Biometrics technologies are gaining popularity today since they provide more reliable and efficient means of authentication and verification. Keystroke Dynamics is one of the famous biometric technologies, which will try to identify the authenticity of a user when the user is working via a keyboard. The authentication process is done by observing the change in the typing pattern of the user. A comprehensive survey of the existing keystroke dynamics methods, metrics, different approaches are given in this study. This paper also discusses about the various security issues and challenges faced by keystroke dynamics.
Quantum-information approach to dynamical diffraction theory
Nsofini, J.; Ghofrani, K.; Sarenac, D.; Cory, D. G.; Pushin, D. A.
2016-12-01
We present a simplified model for dynamical diffraction of particles through a periodic thick perfect crystal based on repeated application of a coherent beam-splitting unitary at coarse-grained lattice sites. By demanding translational invariance and a computationally tractable number of sites in the coarse graining, we show how this approach reproduces many results typical of dynamical diffraction theory and experiments. This approach has the benefit of being applicable in the thick, thin, and intermediate crystal regimes. The method is applied to a three-blade neutron interferometer to predict the output beam profiles, interference patterns, and contrast variation.
"Intensive Research Program on Advances in Nonsmooth Dynamics 2016
Jeffrey, Mike; Lázaro, J; Olm, Josep
2017-01-01
This volume contains extended abstracts outlining selected talks and other selected presentations given by participants throughout the "Intensive Research Program on Advances in Nonsmooth Dynamics 2016", held at the Centre de Recerca Matemàtica (CRM) in Barcelona from February 1st to April 29th, 2016. They include brief research articles reporting new results, descriptions of preliminary work or open problems, and outlines of prominent discussion sessions. The articles are all the result of direct collaborations initiated during the research program. The topic is the theory and applications of Nonsmooth Dynamics. This includes systems involving elements of: impacting, switching, on/off control, hybrid discrete-continuous dynamics, jumps in physical properties, and many others. Applications include: electronics, climate modeling, life sciences, mechanics, ecology, and more. Numerous new results are reported concerning the dimensionality and robustness of nonsmooth models, shadowing variables, numbers of limit...
Dynamic analysis of spur gears using computer program DANST
Oswald, Fred B.; Lin, Hsiang H.; Liou, Chuen-Huei; Valco, Mark J.
1993-06-01
DANST is a computer program for static and dynamic analysis of spur gear systems. The program can be used for parametric studies to predict the effect on dynamic load and tooth bending stress of spur gears due to operating speed, torque, stiffness, damping, inertia, and tooth profile. DANST performs geometric modeling and dynamic analysis for low- or high-contact-ratio spur gears. DANST can simulate gear systems with contact ratio ranging from one to three. It was designed to be easy to use, and it is extensively documented by comments in the source code. This report describes the installation and use of DANST. It covers input data requirements and presents examples. The report also compares DANST predictions for gear tooth loads and bending stress to experimental and finite element results.
A Hybrid Dynamic Programming Method for Concave Resource Allocation Problems
Institute of Scientific and Technical Information of China (English)
姜计荣; 孙小玲
2005-01-01
Concave resource allocation problem is an integer programming problem of minimizing a nonincreasing concave function subject to a convex nondecreasing constraint and bounded integer variables. This class of problems are encountered in optimization models involving economies of scale. In this paper, a new hybrid dynamic programming method was proposed for solving concave resource allocation problems. A convex underestimating function was used to approximate the objective function and the resulting convex subproblem was solved with dynamic programming technique after transforming it into a 0-1 linear knapsack problem. To ensure the convergence, monotonicity and domain cut technique was employed to remove certain integer boxes and partition the revised domain into a union of integer boxes. Computational results were given to show the efficiency of the algorithm.
Benchmarking novel approaches for modelling species range dynamics.
Zurell, Damaris; Thuiller, Wilfried; Pagel, Jörn; Cabral, Juliano S; Münkemüller, Tamara; Gravel, Dominique; Dullinger, Stefan; Normand, Signe; Schiffers, Katja H; Moore, Kara A; Zimmermann, Niklaus E
2016-08-01
Increasing biodiversity loss due to climate change is one of the most vital challenges of the 21st century. To anticipate and mitigate biodiversity loss, models are needed that reliably project species' range dynamics and extinction risks. Recently, several new approaches to model range dynamics have been developed to supplement correlative species distribution models (SDMs), but applications clearly lag behind model development. Indeed, no comparative analysis has been performed to evaluate their performance. Here, we build on process-based, simulated data for benchmarking five range (dynamic) models of varying complexity including classical SDMs, SDMs coupled with simple dispersal or more complex population dynamic models (SDM hybrids), and a hierarchical Bayesian process-based dynamic range model (DRM). We specifically test the effects of demographic and community processes on model predictive performance. Under current climate, DRMs performed best, although only marginally. Under climate change, predictive performance varied considerably, with no clear winners. Yet, all range dynamic models improved predictions under climate change substantially compared to purely correlative SDMs, and the population dynamic models also predicted reasonable extinction risks for most scenarios. When benchmarking data were simulated with more complex demographic and community processes, simple SDM hybrids including only dispersal often proved most reliable. Finally, we found that structural decisions during model building can have great impact on model accuracy, but prior system knowledge on important processes can reduce these uncertainties considerably. Our results reassure the clear merit in using dynamic approaches for modelling species' response to climate change but also emphasize several needs for further model and data improvement. We propose and discuss perspectives for improving range projections through combination of multiple models and for making these approaches
Approach of generating parallel programs from parallelized algorithm design strategies
Institute of Scientific and Technical Information of China (English)
WAN Jian-yi; LI Xiao-ying
2008-01-01
Today, parallel programming is dominated by message passing libraries, such as message passing interface (MPI). This article intends to simplify parallel programming by generating parallel programs from parallelized algorithm design strategies. It uses skeletons to abstract parallelized algorithm design strategies, as well as parallel architectures. Starting from problem specification, an abstract parallel abstract programming language+ (Apla+) program is generated from parallelized algorithm design strategies and problem-specific function definitions. By combining with parallel architectures, implicity of parallelism inside the parallelized algorithm design strategies is exploited. With implementation and transformation, C++ and parallel virtual machine (CPPVM) parallel program is finally generated. Parallelized branch and bound (B&B) algorithm design strategy and parallelized divide and conquer (D & C) algorithm design strategy are studied in this article as examples. And it also illustrates the approach with a case study.
A linear programming approach for optimal contrast-tone mapping.
Wu, Xiaolin
2011-05-01
This paper proposes a novel algorithmic approach of image enhancement via optimal contrast-tone mapping. In a fundamental departure from the current practice of histogram equalization for contrast enhancement, the proposed approach maximizes expected contrast gain subject to an upper limit on tone distortion and optionally to other constraints that suppress artifacts. The underlying contrast-tone optimization problem can be solved efficiently by linear programming. This new constrained optimization approach for image enhancement is general, and the user can add and fine tune the constraints to achieve desired visual effects. Experimental results demonstrate clearly superior performance of the new approach over histogram equalization and its variants.
A dynamic appearance descriptor approach to facial actions temporal modeling.
Jiang, Bihan; Valstar, Michel; Martinez, Brais; Pantic, Maja
2014-02-01
Both the configuration and the dynamics of facial expressions are crucial for the interpretation of human facial behavior. Yet to date, the vast majority of reported efforts in the field either do not take the dynamics of facial expressions into account, or focus only on prototypic facial expressions of six basic emotions. Facial dynamics can be explicitly analyzed by detecting the constituent temporal segments in Facial Action Coding System (FACS) Action Units (AUs)-onset, apex, and offset. In this paper, we present a novel approach to explicit analysis of temporal dynamics of facial actions using the dynamic appearance descriptor Local Phase Quantization from Three Orthogonal Planes (LPQ-TOP). Temporal segments are detected by combining a discriminative classifier for detecting the temporal segments on a frame-by-frame basis with Markov Models that enforce temporal consistency over the whole episode. The system is evaluated in detail over the MMI facial expression database, the UNBC-McMaster pain database, the SAL database, the GEMEP-FERA dataset in database-dependent experiments, in cross-database experiments using the Cohn-Kanade, and the SEMAINE databases. The comparison with other state-of-the-art methods shows that the proposed LPQ-TOP method outperforms the other approaches for the problem of AU temporal segment detection, and that overall AU activation detection benefits from dynamic appearance information.
Marketing: an approach to successful energy-conservation information programs
Energy Technology Data Exchange (ETDEWEB)
Hutton, R. B.; McNeill, D. L.
1980-08-01
This monograph shows how the adoption of a marketing approach can improve the quality of the development and delivery of energy-conservation programs. Several factors make the use of such a marketing approach to conservation particularly beneficial, namely: (1) goals of conservation programs can be quantified (e.g., specified amount of energy to be saved); in addition, intermediate effects necessary for program success are also measureable (e.g., knowledge, attitude change, etc); (2) there is an apparent and increasing need for conservation by different parts (or sectors) of the population; however, it is clear that the desire for conservation is not the same for all sectors; (3) conservation programs can be thought of in much the same way as products with benefits and costs; this necessitates an understanding of how the population makes conservation decisions so that the program can fit into that decision process; (4) the need to tailor programs to the needs of the population is heightened by the general competition for the consumer dollar; it is necessary to design and present programs in a way that the individual will view conservation as an attractive choice among many (e.g., bank savings, buying clothes, furniture, car, etc.); and (5) the population's response to, and need for conservation is constantly changing; consequently, it is important to realize that these changes may need to be reflected in the conservation programs themselves (both ongoing and new).
Many-body approach to the dynamics of batch learning
Wong, K. Y. Michael; Li, S.; Tong, Y. W.
2000-09-01
Using the cavity method and diagrammatic methods, we model the dynamics of batch learning of restricted sets of examples, widely applicable to general learning cost functions, and fully taking into account the temporal correlations introduced by the recycling of the examples. The approach is illustrated using the Adaline rule learning teacher-generated or random examples.
The dynamics of alliances : a game theoretical approach
Ridder, A. de
2007-01-01
In this dissertation, Annelies de Ridder presents a game theoretical approach to strategic alliances. More specifically, the dynamics of and within alliances have been studied. To do so, four new models have been developed in the game theoretical tradition. Both coalition theory and strategic game t
New Approach to Cluster Synchronization in Complex Dynamical Networks
Institute of Scientific and Technical Information of China (English)
LU Xin-Biao; QIN Bu-Zhi; LU Xin-Yu
2009-01-01
In this paper, a distributed control strategy is proposed to make a complex dynamical network achieve cluster synchronization, which means that nodes in the same group achieve the same synchronization state, while nodes in different groups achieve different synchronization states. The local and global stability of the cluster synchronization state are analyzed. Moreover, simulation results verify the effectiveness of the new approach
Remotely sensed monitoring of small reservoir dynamics: a Bayesian approach
Eilander, D.M.; Annor, F.O.; Iannini, L.; Van de Giesen, N.C.
2014-01-01
Multipurpose small reservoirs are important for livelihoods in rural semi-arid regions. To manage and plan these reservoirs and to assess their hydrological impact at a river basin scale, it is important to monitor their water storage dynamics. This paper introduces a Bayesian approach for monitorin
Effective action approach to dynamical generation of fermion mixing
Blasone, Massimo; Smaldone, Luca
2016-01-01
In this paper we discuss a mechanism for the dynamical generation of flavor mixing, in the framework of the Nambu--Jona Lasinio model. Our approach is illustrated both with the conventional operatorial formalism and with functional integral and ensuing one-loop effective action. The results obtained are briefly discussed.
A Case Study on Air Combat Decision Using Approximated Dynamic Programming
Directory of Open Access Journals (Sweden)
Yaofei Ma
2014-01-01
Full Text Available As a continuous state space problem, air combat is difficult to be resolved by traditional dynamic programming (DP with discretized state space. The approximated dynamic programming (ADP approach is studied in this paper to build a high performance decision model for air combat in 1 versus 1 scenario, in which the iterative process for policy improvement is replaced by mass sampling from history trajectories and utility function approximating, leading to high efficiency on policy improvement eventually. A continuous reward function is also constructed to better guide the plane to find its way to “winner” state from any initial situation. According to our experiments, the plane is more offensive when following policy derived from ADP approach other than the baseline Min-Max policy, in which the “time to win” is reduced greatly but the cumulated probability of being killed by enemy is higher. The reason is analyzed in this paper.
Xu, Jiuping; Zeng, Ziqiang; Han, Bernard; Lei, Xiao
2013-07-01
This article presents a dynamic programming-based particle swarm optimization (DP-based PSO) algorithm for solving an inventory management problem for large-scale construction projects under a fuzzy random environment. By taking into account the purchasing behaviour and strategy under rules of international bidding, a multi-objective fuzzy random dynamic programming model is constructed. To deal with the uncertainties, a hybrid crisp approach is used to transform fuzzy random parameters into fuzzy variables that are subsequently defuzzified by using an expected value operator with optimistic-pessimistic index. The iterative nature of the authors' model motivates them to develop a DP-based PSO algorithm. More specifically, their approach treats the state variables as hidden parameters. This in turn eliminates many redundant feasibility checks during initialization and particle updates at each iteration. Results and sensitivity analysis are presented to highlight the performance of the authors' optimization method, which is very effective as compared to the standard PSO algorithm.
Genetic Programming Approach for Predicting Surface Subsidence Induced by Mining
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
The surface subsidence induced by mining is a complex problem, which is related with many complex and uncertain factors.Genetic programming (GP) has a good ability to deal with complex and nonlinear problems, therefore genetic programming approach is proposed to predict mining induced surface subsidence in this article.First genetic programming technique is introduced, second, surface subsidence genetic programming model is set up by selecting its main affective factors and training relating to practical engineering data, and finally, predictions are made by the testing of data, whose results show that the relative error is approximately less than 10%, which can meet the engineering needs, and therefore, this proposed approach is valid and applicable in predicting mining induced surface subsidence.The model offers a novel method to predict surface subsidence in mining.
AN UTILITIES BASED APPROACH FOR MULTI-PERIOD DYNAMIC PORTFOLIO SELECTION
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
This paper proposed a multi-period dynamic optimal portfolio selection model. Assumptions were made to assure the strictness of reasoning. This Approach depicted the developments and changing of the real stock market and is an attempt to remedy some of the deficiencies of recent researches. The model is a standard form of quadratic programming. Furthermore, this paper presented a numerical example in real stock market.
DYNAMIC PROGRAMMING AND ADAPTIVE PROCESSES--1: MATHEMATICAL FOUNDATION
engulf the field of operations research, and play a paramount role in the current theory of stochastic control processes of ejectronic and mechanical ...origin. All three of these domains merge in the consideration of the problems of communication theory. The functional equation approach of dynamic
Concurrent object-oriented programming: The MP-Eiffel approach
Silva, Miguel Augusto Mendes Oliveira e
2004-01-01
This article evaluates several possible approaches for integrating concurrency into object-oriented programming languages, presenting afterwards, a new language named MP-Eiffel. MP-Eiffel was designed attempting to include all the essential properties of both concurrent and object-oriented programming with simplicity and safety. A special care was taken to achieve the orthogonality of all the language mechanisms, allowing their joint use without unsafe side-effects (such as inh...
Semi-supervised Graph Embedding Approach to Dynamic Link Prediction
Hisano, Ryohei
2016-01-01
We propose a simple discrete time semi-supervised graph embedding approach to link prediction in dynamic networks. The learned embedding reflects information from both the temporal and cross-sectional network structures, which is performed by defining the loss function as a weighted sum of the supervised loss from past dynamics and the unsupervised loss of predicting the neighborhood context in the current network. Our model is also capable of learning different embeddings for both formation and dissolution dynamics. These key aspects contributes to the predictive performance of our model and we provide experiments with three real--world dynamic networks showing that our method is comparable to state of the art methods in link formation prediction and outperforms state of the art baseline methods in link dissolution prediction.
Direct heuristic dynamic programming for nonlinear tracking control with filtered tracking error.
Yang, Lei; Si, Jennie; Tsakalis, Konstantinos S; Rodriguez, Armando A
2009-12-01
This paper makes use of the direct heuristic dynamic programming design in a nonlinear tracking control setting with filtered tracking error. A Lyapunov stability approach is used for the stability analysis of the tracking system. It is shown that the closed-loop tracking error and the approximating neural network weight estimates retain the property of uniformly ultimate boundedness under the presence of neural network approximation error and bounded unknown disturbances under certain conditions.
Rethink, Reform, Reenter: An Entrepreneurial Approach to Prison Programming.
Keena, Linda; Simmons, Chris
2015-07-01
The purpose of this article was to present a description and first-stage evaluation of the impact of the Ice House Entrepreneurship Program on the learning experience of participating prerelease inmates at a Mississippi maximum-security prison and their perception of the transfer of skills learned in program into securing employment upon reentry. The Ice House Entrepreneurship Program is a 12-week program facilitated by volunteer university professors to inmates in a prerelease unit of a maximum-security prison in Mississippi. Participants' perspectives were examined through content analysis of inmates' answers to program Reflection and Response Assignments and interviews. The analyses were conducted according to the constant comparative method. Findings reveal the emergent of eight life-lessons and suggest that this is a promising approach to prison programming for prerelease inmates. This study discusses three approaches to better prepare inmates for a mindset change. The rethink, reform, and reenter approaches help break the traditional cycle of release, reoffend, and return. © The Author(s) 2014.
DISTRIBUTED APPROACH to WEB PAGE CATEGORIZATION USING MAPREDUCE PROGRAMMING MODEL
Directory of Open Access Journals (Sweden)
P.Malarvizhi
2011-12-01
Full Text Available The web is a large repository of information and to facilitate the search and retrieval of pages from it,categorization of web documents is essential. An effective means to handle the complexity of information retrieval from the internet is through automatic classification of web pages. Although lots of automatic classification algorithms and systems have been presented, most of the existing approaches are computationally challenging. In order to overcome this challenge, we have proposed a parallel algorithm, known as MapReduce programming model to automatically categorize the web pages. This approach incorporates three concepts. They are web crawler, MapReduce programming model and the proposed web page categorization approach. Initially, we have utilized web crawler to mine the World Wide Web and the crawled web pages are then directly given as input to the MapReduce programming model. Here the MapReduce programming model adapted to our proposed web page categorization approach finds the appropriate category of the web page according to its content. The experimental results show that our proposed parallel web page categorization approach achieves satisfactory results in finding the right category for any given web page.
Institute of Scientific and Technical Information of China (English)
LIU Xiao; WANG Cheng-en
2005-01-01
This paper addresses a single item dynamic lot-sizing model with inventory capacity and out-sourcing. The goal is to minimize the total costs of production, setup, inventory holding and out-sourcing. Two versions of an out-sourcing model with time-varying costs are considered: stock out case and conservation case. Zero Inventory Order property has been found and some new properties are obtained in an optimal solution. Dynamic programming algorithms are developed to solve the problem in strongly polynomial time respectively. Furthermore, some numerical results demonstrate that the approach proposed is efficient and applicable.
Spectral properties of the one-dimensional Hubbard model: cluster dynamical mean-field approaches
Go, Ara; Jeon, Gun Sang
2011-03-01
We investigate static and dynamic properties of the one-dimensional Hubbard model using cluster extensions of the dynamical mean-field theory. It is shown that the two different extensions, the cellular dynamical mean-field theory and the dynamic cluster approximation, yield the ground-state properties which are qualitatively in good agreement with each other. We compare the results with the Bethe ansatz results to check the accuracy of the calculation with finite sizes of clusters. We also analyze the spectral properties of the model with the focus on the spin-charge separation and discuss the dependency on the cluster size in the two approaches. This research was supported by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Education, Science and Technology(2010-0010937).
An MC2 Linear Programming Approaches to Portfolios
Institute of Scientific and Technical Information of China (English)
ZHOU Zong-fang; TANG Xiao-wo; SHI Yong
2002-01-01
Portfolios is a well-known investment technique of handling multiple stocks, bonds and securities. However, the previous portfolios investment lack of incorporating the various possible opinions from several experts on an given portfolios investment problem. This paper proposes an MC2 linear programming approach to determining weighted coefficients of portfolios that involves multiple experts. The numerical example of the paper shows that the proposed approach likely outperforms the current techniques of portfolios in dealing with the case of multiple experts.
Overview of the solar dynamic ground test demonstration program
Shaltens, Richard K.; Boyle, Robert V.
1993-01-01
The Solar Dynamic (SD) Ground Test Demonstration (GTD) program demonstrates the availability of SD technologies in a simulated space environment at the NASA Lewis Research Center (LeRC) vacuum facility. An aerospace industry/ government team is working together to design, fabricate, build, and test a complete SD system. This paper reviews the goals and status of the SD GTD program. A description of the SD system includes key design features of the system, subsystems, and components as reported at the Critical Design Review (CDR).
A dynamic approach to communication in health literacy education.
Veenker, Herman; Paans, Wolter
2016-10-21
-Message-Receiver Model; and b) only a few interventions in curricula are available for providing the acquisition of interaction skills in supporting autonomy. The proposal of Huber and others to change the emphasis in the definition of the WHO definition on health towards "to adapt and self manage" has impact on the training of medical students and practioners in dealing with patients with low levels of health literacy. From the present study it can be concluded that a dynamic approach to communication can be linked to theoretical constructs on self-management. In such an approach interaction techniques like scaffolding can increase the level of HL of the patient.
Zhong, Xiangnan; He, Haibo; Zhang, Huaguang; Wang, Zhanshan
2014-12-01
In this paper, we develop and analyze an optimal control method for a class of discrete-time nonlinear Markov jump systems (MJSs) with unknown system dynamics. Specifically, an identifier is established for the unknown systems to approximate system states, and an optimal control approach for nonlinear MJSs is developed to solve the Hamilton-Jacobi-Bellman equation based on the adaptive dynamic programming technique. We also develop detailed stability analysis of the control approach, including the convergence of the performance index function for nonlinear MJSs and the existence of the corresponding admissible control. Neural network techniques are used to approximate the proposed performance index function and the control law. To demonstrate the effectiveness of our approach, three simulation studies, one linear case, one nonlinear case, and one single link robot arm case, are used to validate the performance of the proposed optimal control method.
DEFF Research Database (Denmark)
Davidsen, Claus; Liu, Suxia; Mo, Xinguo
2014-01-01
costs. As in traditional SDP approaches, one step-ahead sub-problems are solved to find the optimal management at any time knowing the inflow scenario and reservoir/aquifer storage levels. These non-linear sub-problems are solved using a genetic algorithm (GA) that minimizes the sum of the immediate......, reservoir states, and inflow scenarios are used as future costs to drive a forward moving simulation under uncertain water availability. The use of a GA to solve the sub-problems is computationally more costly than a traditional SDP approach with linearly interpolated future costs. However, in a two....... A stochastic dynamic programming (SDP) approach is used to minimize the basin-wide total costs arising from water allocations and water curtailments. Dynamic allocation problems with inclusion of groundwater resources proved to be more complex to solve with SDP than pure surface water allocation problems due...
Optimal Design of Measurement Programs for the Parameter Identification of Dynamic Systems
DEFF Research Database (Denmark)
Kirkegaard, Poul Henning; Sørensen, John Dalsgaard; Brincker, Rune
The design of measurement programs devoted to parameter identification of structural dynamic systems is considered. The design problem is formulated as an optimization problem to minimize the total expected cost that is the cost of failure and the cost of the measurement program. All the calculat...... for estimating the modal damping parameters in a simply supported plane, vibrating beam model. Results show optimal number of sensors and their locations....... the calculations are based on a priori knowledge and engineering judgement. One of the contribution of the approach is that the optimal number of sensors can be estimated. This is shown in a numerical example where the proposed approach is demonstrated. The example is concerned with design of a measurement program...
Systems and methods for interpolation-based dynamic programming
Rockwood, Alyn
2013-01-03
Embodiments of systems and methods for interpolation-based dynamic programming. In one embodiment, the method includes receiving an object function and a set of constraints associated with the objective function. The method may also include identifying a solution on the objective function corresponding to intersections of the constraints. Additionally, the method may include generating an interpolated surface that is in constant contact with the solution. The method may also include generating a vector field in response to the interpolated surface.
SEWER NETWORK DISCHARGE OPTIMIZATION USING THE DYNAMIC PROGRAMMING
Directory of Open Access Journals (Sweden)
Viorel MINZU
2015-12-01
Full Text Available It is necessary to adopt an optimal control that allows an efficient usage of the existing sewer networks, in order to avoid the building of new retention facilities. The main objective of the control action is to minimize the overflow volume of a sewer network. This paper proposes a method to apply a solution obtained by discrete dynamic programming through a realistic closed loop system.
Dynamical system approach to scalar-vector-tensor cosmology
Ghaffarnejad, H
2016-01-01
We use scalar-vector-tensor gravity [1] which is obtained by generalizing Brans Dicke (BD) gravity model [2] via dynamical vector field. We study flat Friedmann Robertson Walker (FRW) cosmology by using dynamical system approach in the presence of self interaction BD potential and perfect fluid matter stress tensor. We obtained 3 critical points for $\\Lambda CDM$ vacuum de Sitter era which one of them is spiral attractor absolutely independent of particular values of the BD parameter $\\omega$ but not two other critical points. The latter take real values only for $-0.54-0.54.$ Even if the eigne values become complex imaginary where $\\omega\
Tozan, Yesim; Ompad, Danielle C
2015-06-01
In a variety of urban health frameworks, cities are conceptualized as complex and dynamic yet commonly used epidemiological methods have failed to address this complexity and dynamism head on due to their narrow problem definitions and linear analytical representations. Scholars from a variety of disciplines have also long conceptualized cities as systems, but few have modeled urban health issues as problems within a system. Systems thinking in general and system dynamics in particular are relatively new approaches in public health, but ones that hold immense promise as methodologies to model and analyze the complexity underlying urban processes to effectively inform policy actions in dynamic environments. This conceptual essay reviews the utility of applying the concepts, principles, and methods of systems thinking to the study of complex urban health phenomena as a complementary approach to standard epidemiological methods using specific examples and provides recommendations on how to better incorporate systems thinking methods in urban health research and practice.
Interdisciplinary approach to a total knee replacement program.
Seemann, S
2000-06-01
An orthopedic clinical nurse specialist facilitated an interdisciplinary evaluation, design, and implementation of best practice initiatives for the total knee replacement patient population using the Center for Advanced Nursing Practice's Evidence-Based Practice Model. The interdisciplinary team approach enhanced the total joint program by achieving positive patient outcomes, demonstrating financial stewardship of resources, and facilitating inter- and intradisciplinary communication.
A Relational Approach to International Education through Homestay Programs
Kobayashi, Junko; Viswat, Linda
2015-01-01
This paper identifies and analyzes intercultural problems through surveys of homestay programs with Japanese students and American host mothers. Given that participants need to go beyond their cognitive knowledge to interact effectively with people from other cultures, a relational approach may be more effective than traditional intercultural…
Training Program Handbook: A systematic approach to training
Energy Technology Data Exchange (ETDEWEB)
1994-08-01
This DOE handbook describes a systematic method for establishing and maintaining training programs that meet the requirements and expectations of DOE Orders 5480.18B and 5480.20. The systematic approach to training includes 5 phases: Analysis, design, development, implementation, and evaluation.
A Dialogue Game Approach to Multi-Agent System Programming
Lebbink, Henk-Jan; Witteman, Cilia; Meyer, John-Jules Ch.
2005-01-01
This paper approaches multi-agent system programming with dialogue games allowing the semantics of communicative acts to be a component in multi-agent architectures. We present a dialogue game for enquiry enabling agents to answer questions in a distributed fashion. In addition, we propose a reasoni
Linear decomposition approach for a class of nonconvex programming problems.
Shen, Peiping; Wang, Chunfeng
2017-01-01
This paper presents a linear decomposition approach for a class of nonconvex programming problems by dividing the input space into polynomially many grids. It shows that under certain assumptions the original problem can be transformed and decomposed into a polynomial number of equivalent linear programming subproblems. Based on solving a series of liner programming subproblems corresponding to those grid points we can obtain the near-optimal solution of the original problem. Compared to existing results in the literature, the proposed algorithm does not require the assumptions of quasi-concavity and differentiability of the objective function, and it differs significantly giving an interesting approach to solving the problem with a reduced running time.
A Matheuristic Approach Combining Local Search and Mathematical Programming
Directory of Open Access Journals (Sweden)
Carolina Lagos
2016-01-01
Full Text Available A novel matheuristic approach is presented and tested on a well-known optimisation problem, namely, capacitated facility location problem (CFLP. The algorithm combines local search and mathematical programming. While the local search algorithm is used to select a subset of promising facilities, mathematical programming strategies are used to solve the subproblem to optimality. Proposed local search is influenced by instance-specific information such as installation cost and the distance between customers and facilities. The algorithm is tested on large instances of the CFLP, where neither local search nor mathematical programming is able to find good quality solutions within acceptable computational times. Our approach is shown to be a very competitive alternative to solve large-scale instances for the CFLP.
动态规划法在程序设计中的应用%Dynamic Programming in Application of Computer Programming
Institute of Scientific and Technical Information of China (English)
邓国强; 唐敏
2014-01-01
探讨动态规划法的本质及在计算机程序设计中的应用。提出求解Fibonacci序列的3种算法，即递归法、自底向上和自顶向下动态规划法，证明将动态规划法用于程序设计，能降低算法的时间复杂度和空间复杂度。%The nature of dynamic programming and its application for computer programming are discussed .We present three methods for solving Fibonacci sequence ,which are the recursive method ,bottom-up approach and top-down ap-proach respectively .The analysis about time complexity and space complexity for three algorithms is demonstrated that if use dynamic programming in computer programming ,the time and space complexity will be decreased .
Runtime software adaptation: approaches and a programming tool
Directory of Open Access Journals (Sweden)
Jarosław Rudy
2012-03-01
Full Text Available Software systems steadily tend to be bigger and more complex, making it more difficult to change them, especially during runtime. Several types of runtime software adaptation approaches were proposed to increase the adaptation capability of applications and turn them into an evolution software. Many of these approaches (using software architectural models for example are implemented during the design phase of software development life cycle, making them ineffective or difficult to use in case of already existing applications. Moreover, the overhead caused by the use of these approaches has not been determined in many cases. In this paper author presents the taxonomy of high- and low-level approaches to runtime software adaptation and then introduces a lightweight prototype programming tool used to add runtime code modification capability (via function hotswapping to existing applications written in C++ and run under Linux. The tool also enables to replace a defective function by its older or corrected version at runtime. Several tests were prepared to compare traditional C++ applications with the same applications developed with the aforementioned programming tool. Applications were compared in terms of execution time, size of executable code and memory usage. Different size and number of functions have been considered. The paper also researches the constant overhead caused by the programming tool regardless of the target application. The paper ends with the summary of presented approaches and their characteristics, including effects on the targeted systems, capabilities, ease of use, level of abstraction etc.
Larocca, Francesco; Chiu, Stephanie J; McNabb, Ryan P; Kuo, Anthony N; Izatt, Joseph A; Farsiu, Sina
2011-06-01
Segmentation of anatomical structures in corneal images is crucial for the diagnosis and study of anterior segment diseases. However, manual segmentation is a time-consuming and subjective process. This paper presents an automatic approach for segmenting corneal layer boundaries in Spectral Domain Optical Coherence Tomography images using graph theory and dynamic programming. Our approach is robust to the low-SNR and different artifact types that can appear in clinical corneal images. We show that our method segments three corneal layer boundaries in normal adult eyes more accurately compared to an expert grader than a second grader-even in the presence of significant imaging outliers.
2015-08-17
our best knowledge , this is the first study of using a “predictive” approach through a model network to design the event-triggered ADP. This is the...investigated in the com- munity before, to our best knowledge , this is the first study of using a “predictive” approach through a model network to...programming has been used to solve the optimal control for many years. However, due to the ” curse of di- mensionality” [9], [10], the adaptive dynamic
Dynamic scaling at classical phase transitions approached through nonequilibrium quenching
Liu, Cheng-Wei; Polkovnikov, Anatoli; Sandvik, Anders W.
2014-02-01
We use Monte Carlo simulations to demonstrate generic scaling aspects of classical phase transitions approached through a quench (or annealing) protocol where the temperature changes as a function of time with velocity v. Using a generalized Kibble-Zurek ansatz, we demonstrate dynamic scaling for different types of stochastic dynamics (Metropolis, Swendsen-Wang, and Wolff) on Ising models in two and higher dimensions. We show that there are dual scaling functions governing the dynamic scaling, which together describe the scaling behavior in the entire velocity range v ∈[0,∞). These functions have asymptotics corresponding to the adiabatic and diabatic limits, and close to these limits they are perturbative in v and 1/v, respectively. Away from their perturbative domains, both functions cross over into the same universal power-law scaling form governed by the static and dynamic critical exponents (as well as an exponent characterizing the quench protocol). As a by-product of the scaling studies, we obtain high-precision estimates of the dynamic exponent z for the two-dimensional Ising model subject to the three variants of Monte Carlo dynamics: for single-spin Metropolis updates zM=2.1767(5), for Swendsen-Wang multicluster updates zSW=0.297(3), and for Wolff single-cluster updates zW=0.30(2). For Wolff dynamics, we find an interesting behavior with a nonanalytic breakdown of the quasiadiabatic and diabatic scalings, instead of the generic smooth crossover described by a power law. We interpret this disconnect between the two scaling regimes as a dynamic phase transition of the Wolff algorithm, caused by an effective sudden loss of ergodicity at high velocity.
Automatic programming via iterated local search for dynamic job shop scheduling.
Nguyen, Su; Zhang, Mengjie; Johnston, Mark; Tan, Kay Chen
2015-01-01
Dispatching rules have been commonly used in practice for making sequencing and scheduling decisions. Due to specific characteristics of each manufacturing system, there is no universal dispatching rule that can dominate in all situations. Therefore, it is important to design specialized dispatching rules to enhance the scheduling performance for each manufacturing environment. Evolutionary computation approaches such as tree-based genetic programming (TGP) and gene expression programming (GEP) have been proposed to facilitate the design task through automatic design of dispatching rules. However, these methods are still limited by their high computational cost and low exploitation ability. To overcome this problem, we develop a new approach to automatic programming via iterated local search (APRILS) for dynamic job shop scheduling. The key idea of APRILS is to perform multiple local searches started with programs modified from the best obtained programs so far. The experiments show that APRILS outperforms TGP and GEP in most simulation scenarios in terms of effectiveness and efficiency. The analysis also shows that programs generated by APRILS are more compact than those obtained by genetic programming. An investigation of the behavior of APRILS suggests that the good performance of APRILS comes from the balance between exploration and exploitation in its search mechanism.
A novel similarity comparison approach for dynamic ECG series.
Yin, Hong; Zhu, Xiaoqian; Ma, Shaodong; Yang, Shuqiang; Chen, Liqian
2015-01-01
The heart sound signal is a reflection of heart and vascular system motion. Long-term continuous electrocardiogram (ECG) contains important information which can be helpful to prevent heart failure. A single piece of a long-term ECG recording usually consists of more than one hundred thousand data points in length, making it difficult to derive hidden features that may be reflected through dynamic ECG monitoring, which is also very time-consuming to analyze. In this paper, a Dynamic Time Warping based on MapReduce (MRDTW) is proposed to make prognoses of possible lesions in patients. Through comparison of a real-time ECG of a patient with the reference sets of normal and problematic cardiac waveforms, the experimental results reveal that our approach not only retains high accuracy, but also greatly improves the efficiency of the similarity measure in dynamic ECG series.
Logical Attractors: a Boolean Approach to the Dynamics of Psychosis
Kupper, Z.; Hoffmann, H.
A Boolean modeling approach to attractors in the dynamics of psychosis is presented: Kinetic Logic, originating from R. Thomas, describes systems on an intermediate level between a purely verbal, qualitative description and a description using nonlinear differential equations. With this method we may model impact, feedback and temporal evolution, as well as analyze the resulting attractors. In our previous research the method has been applied to general and more specific questions in the dynamics of psychotic disorders. In this paper a model is introduced that describes different dynamical patterns of chronic psychosis in the context of vocational rehabilitation. It also shows to be useful in formulating and exploring possible treatment strategies. Finally, some of the limitations and benefits of Kinetic Logic as a modeling tool for psychology and psychiatry are discussed.
A Dynamic Linear Modeling Approach to Public Policy Change
DEFF Research Database (Denmark)
Loftis, Matthew; Mortensen, Peter Bjerre
2017-01-01
Theories of public policy change, despite their differences, converge on one point of strong agreement. The relationship between policy and its causes can and does change over time. This consensus yields numerous empirical implications, but our standard analytical tools are inadequate for testing...... them. As a result, the dynamic and transformative relationships predicted by policy theories have been left largely unexplored in time-series analysis of public policy. This paper introduces dynamic linear modeling (DLM) as a useful statistical tool for exploring time-varying relationships in public...... policy. The paper offers a detailed exposition of the DLM approach and illustrates its usefulness with a time series analysis of U.S. defense policy from 1957-2010. The results point the way for a new attention to dynamics in the policy process and the paper concludes with a discussion of how...
A Review on Ab Initio Approaches for Multielectron Dynamics
Ishikawa, Kenichi L
2015-01-01
In parallel with the evolution of femtosecond and attosecond laser as well as free-electron laser technology, a variety of theoretical methods have been developed to describe the behavior of atoms, molecules, clusters, and solids under the action of those laser pulses. Here we review major ab initio wave-function-based numerical approaches to simulate multielectron dynamics in atoms and molecules driven by intense long-wavelength and/or ultrashort short-wavelength laser pulses. Direct solution of the time-dependent Schr\\"odinger equation (TDSE), though its applicability is limited to He, ${\\rm H}_2$, and Li, can provide an exact description and has been greatly contributing to the understanding of dynamical electron-electron correlation. Multiconfiguration self-consistent-field (MCSCF) approach offers a flexible framework from which a variety of methods can be derived to treat both atoms and molecules, with possibility to systematically control the accuracy. The equations of motion of configuration interactio...
Norby, W. P.; Ladd, J. A.; Yuhas, A. J.
1996-01-01
A procedure has been developed for predicting peak dynamic inlet distortion. This procedure combines Computational Fluid Dynamics (CFD) and distortion synthesis analysis to obtain a prediction of peak dynamic distortion intensity and the associated instantaneous total pressure pattern. A prediction of the steady state total pressure pattern at the Aerodynamic Interface Plane is first obtained using an appropriate CFD flow solver. A corresponding inlet turbulence pattern is obtained from the CFD solution via a correlation linking root mean square (RMS) inlet turbulence to a formulation of several CFD parameters representative of flow turbulence intensity. This correlation was derived using flight data obtained from the NASA High Alpha Research Vehicle flight test program and several CFD solutions at conditions matching the flight test data. A distortion synthesis analysis is then performed on the predicted steady state total pressure and RMS turbulence patterns to yield a predicted value of dynamic distortion intensity and the associated instantaneous total pressure pattern.
Zhou, Yuan; Cheng, Xinyao; Xu, Xiangyang; Song, Enmin
2013-12-01
Segmentation of carotid artery intima-media in longitudinal ultrasound images for measuring its thickness to predict cardiovascular diseases can be simplified as detecting two nearly parallel boundaries within a certain distance range, when plaque with irregular shapes is not considered. In this paper, we improve the implementation of two dynamic programming (DP) based approaches to parallel boundary detection, dual dynamic programming (DDP) and piecewise linear dual dynamic programming (PL-DDP). Then, a novel DP based approach, dual line detection (DLD), which translates the original 2-D curve position to a 4-D parameter space representing two line segments in a local image segment, is proposed to solve the problem while maintaining efficiency and rotation invariance. To apply the DLD to ultrasound intima-media segmentation, it is imbedded in a framework that employs an edge map obtained from multiplication of the responses of two edge detectors with different scales and a coupled snake model that simultaneously deforms the two contours for maintaining parallelism. The experimental results on synthetic images and carotid arteries of clinical ultrasound images indicate improved performance of the proposed DLD compared to DDP and PL-DDP, with respect to accuracy and efficiency.
A Bootstrap Approach to an Affordable Exploration Program
Oeftering, Richard C.
2011-01-01
This paper examines the potential to build an affordable sustainable exploration program by adopting an approach that requires investing in technologies that can be used to build a space infrastructure from very modest initial capabilities. Human exploration has had a history of flight programs that have high development and operational costs. Since Apollo, human exploration has had very constrained budgets and they are expected be constrained in the future. Due to their high operations costs it becomes necessary to consider retiring established space facilities in order to move on to the next exploration challenge. This practice may save cost in the near term but it does so by sacrificing part of the program s future architecture. Human exploration also has a history of sacrificing fully functional flight hardware to achieve mission objectives. An affordable exploration program cannot be built when it involves billions of dollars of discarded space flight hardware, instead, the program must emphasize preserving its high value space assets and building a suitable permanent infrastructure. Further this infrastructure must reduce operational and logistics cost. The paper examines the importance of achieving a high level of logistics independence by minimizing resource consumption, minimizing the dependency on external logistics, and maximizing the utility of resources available. The approach involves the development and deployment of a core suite of technologies that have minimum initial needs yet are able expand upon initial capability in an incremental bootstrap fashion. The bootstrap approach incrementally creates an infrastructure that grows and becomes self sustaining and eventually begins producing the energy, products and consumable propellants that support human exploration. The bootstrap technologies involve new methods of delivering and manipulating energy and materials. These technologies will exploit the space environment, minimize dependencies, and
Building enterprise reuse program--A model-based approach
Institute of Scientific and Technical Information of China (English)
梅宏; 杨芙清
2002-01-01
Reuse is viewed as a realistically effective approach to solving software crisis. For an organization that wants to build a reuse program, technical and non-technical issues must be considered in parallel. In this paper, a model-based approach to building systematic reuse program is presented. Component-based reuse is currently a dominant approach to software reuse. In this approach, building the right reusable component model is the first important step. In order to achieve systematic reuse, a set of component models should be built from different perspectives. Each of these models will give a specific view of the components so as to satisfy different needs of different persons involved in the enterprise reuse program. There already exist some component models for reuse from technical perspectives. But less attention is paid to the reusable components from a non-technical view, especially from the view of process and management. In our approach, a reusable component model--FLP model for reusable component--is introduced. This model describes components from three dimensions (Form, Level, and Presentation) and views components and their relationships from the perspective of process and management. It determines the sphere of reusable components, the time points of reusing components in the development process, and the needed means to present components in terms of the abstraction level, logic granularity and presentation media. Being the basis on which the management and technical decisions are made, our model will be used as the kernel model to initialize and normalize a systematic enterprise reuse program.
An epidemiologic approach to computerized medical diagnosis--AEDMI program.
Ferrer Salvans, P; Alonso Vallès, L
1990-01-01
A program called "An Epidemiological Approach to Computerized Medical Diagnosis" (AEDMI) is presented. Using an interactive questionnaire, physician-patient interviews are conducted and a summary of the relevant clinical data is provided. Standard items, obtained on a multi-centre basis, form a large-scale data base. Simultaneously, the reasoning of clinical experts in each real case is analyzed to obtain a knowledge-rules data base. The methodology of the program combines Bayesian systems, expert systems, and other new lines of research such as neural networks or case-based reasoning. The general concepts of clinical decision making aid systems are reviewed. This publication is aimed at obtaining international cooperation.
Dynamics of a wellness program: a conservation of resources perspective.
Kim, Sung Doo; Hollensbe, Elaine C; Schwoerer, Catherine E; Halbesleben, Jonathon R B
2015-01-01
We leverage conservation of resources theory to explain possible dynamics through which a holistic wellness program results in positive longer-term outcomes. Specifically, we hypothesize that wellness self-efficacy at the end of a wellness program will create a positive resource gain spiral, increasing psychological availability (a sense of having cognitive, physical, and emotional resources to engage oneself) 6 months later, and career satisfaction, 1 year later. To test these hypotheses, using a time-lagged with control group design, we gathered questionnaire data from 160 Episcopal priests who participated in a 10-day off-site wellness program. We developed a scale measuring self-efficacy in the 4 wellness areas the program was designed to improve: physical, spiritual, financial, and vocational. Our findings provide evidence from a field setting of a relatively untested tenet of conservation of resources theory, resource gain spirals. The wellness program that we studied served as an opportunity for participants to gain new resources in the form of wellness self-efficacy, which in turn helped participants experience positive outcomes over time. We discuss theoretical and practical implications of the findings.
A Stereo Dual-Channel Dynamic Programming Algorithm for UAV Image Stitching.
Li, Ming; Chen, Ruizhi; Zhang, Weilong; Li, Deren; Liao, Xuan; Wang, Lei; Pan, Yuanjin; Zhang, Peng
2017-09-08
Dislocation is one of the major challenges in unmanned aerial vehicle (UAV) image stitching. In this paper, we propose a new algorithm for seamlessly stitching UAV images based on a dynamic programming approach. Our solution consists of two steps: Firstly, an image matching algorithm is used to correct the images so that they are in the same coordinate system. Secondly, a new dynamic programming algorithm is developed based on the concept of a stereo dual-channel energy accumulation. A new energy aggregation and traversal strategy is adopted in our solution, which can find a more optimal seam line for image stitching. Our algorithm overcomes the theoretical limitation of the classical Duplaquet algorithm. Experiments show that the algorithm can effectively solve the dislocation problem in UAV image stitching, especially for the cases in dense urban areas. Our solution is also direction-independent, which has better adaptability and robustness for stitching images.
Evaluating a physician leadership development program - a mixed methods approach.
Throgmorton, Cheryl; Mitchell, Trey; Morley, Tom; Snyder, Marijo
2016-05-16
Purpose - With the extent of change in healthcare today, organizations need strong physician leaders. To compensate for the lack of physician leadership education, many organizations are sending physicians to external leadership programs or developing in-house leadership programs targeted specifically to physicians. The purpose of this paper is to outline the evaluation strategy and outcomes of the inaugural year of a Physician Leadership Academy (PLA) developed and implemented at a Michigan-based regional healthcare system. Design/methodology/approach - The authors applied the theoretical framework of Kirkpatrick's four levels of evaluation and used surveys, observations, activity tracking, and interviews to evaluate the program outcomes. The authors applied grounded theory techniques to the interview data. Findings - The program met targeted outcomes across all four levels of evaluation. Interview themes focused on the significance of increasing self-awareness, building relationships, applying new skills, and building confidence. Research limitations/implications - While only one example, this study illustrates the importance of developing the evaluation strategy as part of the program design. Qualitative research methods, often lacking from learning evaluation design, uncover rich themes of impact. The study supports how a PLA program can enhance physician learning, engagement, and relationship building throughout and after the program. Physician leaders' partnership with organization development and learning professionals yield results with impact to individuals, groups, and the organization. Originality/value - Few studies provide an in-depth review of evaluation methods and outcomes of physician leadership development programs. Healthcare organizations seeking to develop similar in-house programs may benefit applying the evaluation strategy outlined in this study.
AbouEisha, Hassan M.
2017-07-13
We consider a class of two-and three-dimensional h-refined meshes generated by an adaptive finite element method. We introduce an element partition tree, which controls the execution of the multi-frontal solver algorithm over these refined grids. We propose and study algorithms with polynomial computational cost for the optimization of these element partition trees. The trees provide an ordering for the elimination of unknowns. The algorithms automatically optimize the element partition trees using extensions of dynamic programming. The construction of the trees by the dynamic programming approach is expensive. These generated trees cannot be used in practice, but rather utilized as a learning tool to propose fast heuristic algorithms. In this first part of our paper we focus on the dynamic programming approach, and draw a sketch of the heuristic algorithm. The second part will be devoted to a more detailed analysis of the heuristic algorithm extended for the case of hp-adaptive
A statistical state dynamics approach to wall turbulence.
Farrell, B F; Gayme, D F; Ioannou, P J
2017-03-13
This paper reviews results obtained using statistical state dynamics (SSD) that demonstrate the benefits of adopting this perspective for understanding turbulence in wall-bounded shear flows. The SSD approach used in this work employs a second-order closure that retains only the interaction between the streamwise mean flow and the streamwise mean perturbation covariance. This closure restricts nonlinearity in the SSD to that explicitly retained in the streamwise constant mean flow together with nonlinear interactions between the mean flow and the perturbation covariance. This dynamical restriction, in which explicit perturbation-perturbation nonlinearity is removed from the perturbation equation, results in a simplified dynamics referred to as the restricted nonlinear (RNL) dynamics. RNL systems, in which a finite ensemble of realizations of the perturbation equation share the same mean flow, provide tractable approximations to the SSD, which is equivalent to an infinite ensemble RNL system. This infinite ensemble system, referred to as the stochastic structural stability theory system, introduces new analysis tools for studying turbulence. RNL systems provide computationally efficient means to approximate the SSD and produce self-sustaining turbulence exhibiting qualitative features similar to those observed in direct numerical simulations despite greatly simplified dynamics. The results presented show that RNL turbulence can be supported by as few as a single streamwise varying component interacting with the streamwise constant mean flow and that judicious selection of this truncated support or 'band-limiting' can be used to improve quantitative accuracy of RNL turbulence. These results suggest that the SSD approach provides new analytical and computational tools that allow new insights into wall turbulence.This article is part of the themed issue 'Toward the development of high-fidelity models of wall turbulence at large Reynolds number'.
A statistical state dynamics approach to wall turbulence
Farrell, B. F.; Gayme, D. F.; Ioannou, P. J.
2017-03-01
This paper reviews results obtained using statistical state dynamics (SSD) that demonstrate the benefits of adopting this perspective for understanding turbulence in wall-bounded shear flows. The SSD approach used in this work employs a second-order closure that retains only the interaction between the streamwise mean flow and the streamwise mean perturbation covariance. This closure restricts nonlinearity in the SSD to that explicitly retained in the streamwise constant mean flow together with nonlinear interactions between the mean flow and the perturbation covariance. This dynamical restriction, in which explicit perturbation-perturbation nonlinearity is removed from the perturbation equation, results in a simplified dynamics referred to as the restricted nonlinear (RNL) dynamics. RNL systems, in which a finite ensemble of realizations of the perturbation equation share the same mean flow, provide tractable approximations to the SSD, which is equivalent to an infinite ensemble RNL system. This infinite ensemble system, referred to as the stochastic structural stability theory system, introduces new analysis tools for studying turbulence. RNL systems provide computationally efficient means to approximate the SSD and produce self-sustaining turbulence exhibiting qualitative features similar to those observed in direct numerical simulations despite greatly simplified dynamics. The results presented show that RNL turbulence can be supported by as few as a single streamwise varying component interacting with the streamwise constant mean flow and that judicious selection of this truncated support or `band-limiting' can be used to improve quantitative accuracy of RNL turbulence. These results suggest that the SSD approach provides new analytical and computational tools that allow new insights into wall turbulence.
Bellucci, Michael A; Coker, David F
2011-07-28
We describe a new method for constructing empirical valence bond potential energy surfaces using a parallel multilevel genetic program (PMLGP). Genetic programs can be used to perform an efficient search through function space and parameter space to find the best functions and sets of parameters that fit energies obtained by ab initio electronic structure calculations. Building on the traditional genetic program approach, the PMLGP utilizes a hierarchy of genetic programming on two different levels. The lower level genetic programs are used to optimize coevolving populations in parallel while the higher level genetic program (HLGP) is used to optimize the genetic operator probabilities of the lower level genetic programs. The HLGP allows the algorithm to dynamically learn the mutation or combination of mutations that most effectively increase the fitness of the populations, causing a significant increase in the algorithm's accuracy and efficiency. The algorithm's accuracy and efficiency is tested against a standard parallel genetic program with a variety of one-dimensional test cases. Subsequently, the PMLGP is utilized to obtain an accurate empirical valence bond model for proton transfer in 3-hydroxy-gamma-pyrone in gas phase and protic solvent.
QUADRATIC BI-LEVEL PROGRAMMING PROBLEM BASED ON FUZZY GOAL PROGRAMMING APPROACH
Directory of Open Access Journals (Sweden)
Partha Pratim Dey
2011-11-01
Full Text Available This paper presents fuzzy goal programming approach to quadratic bi-level programming problem. Inthe model formulation of the problem, we construct the quadratic membership functions by determiningindividual best solutions of the quadratic objective functions subject to the system constraints. Thequadratic membership functions are then transformed into equivalent linear membership functions byfirst order Taylor series approximation at the individual best solution point. Since the objectives of upperand lower level decision makers are potentially conflicting in nature, a possible relaxation of each leveldecisions are considered by providing preference bounds on the decision variables for avoiding decisiondeadlock. Then fuzzy goal programming approach is used for achieving highest degree of each of themembership goals by minimizing deviational variables. Numerical examples are provided in order todemonstrate the efficiency of the proposed approach.
Penalized interior point approach for constrained nonlinear programming
Institute of Scientific and Technical Information of China (English)
LU Wen-ting; YAO Yi-rong; ZHANG Lian-sheng
2009-01-01
A penalized interior point approach for constrained nonlinear programming is examined in this work. To overcome the difficulty of initialization for the interior point method, a problem equivalent to the primal problem via incorporating an auxiliary variable is constructed. A combined approach of logarithm barrier and quadratic penalty function is proposed to solve the problem. Based on Newton's method, the global convergence of interior point and line search algorithm is proven.Only a finite number of iterations is required to reach an approximate optimal solution. Numerical tests are given to show the effectiveness of the method.
Program Management Approach to the Territorial Development of Small Business
Directory of Open Access Journals (Sweden)
Natalia Aleksandrovna Knysh
2016-06-01
Full Text Available This article presents the results of the research of the application on a state level of the program management approach to the territorial development of small business. Studying the main mechanism of the state policy implementation in the sphere of small business on a regional level, the authors have revealed the necessity to take into account the territorial specificity while the government programs of small business development are being formed. The analysis of the national practice of utilizing the program management mechanism in the regional system of the government support of small entrepreneurship was conducted on the example of Omsk region. The results of the analysis have shown the inefficiency of the current support system for small business and have determined the need to create an integrated model of territorial programming, which would not only contribute to the qualitative development of small business, but also provide the functioning efficiency of program management mechanism. As a result, the authors have created the two-level model of the programming of the territorial development of small business, which allows to satisfy purposefully the needs of entrepreneurship taking into account the specificity of the internal and external environment of the region. The first level of the model is methodological one and it is based on the marketing approach (the concepts of place marketing and relationship marketing to the operation of the program management mechanism. The second level of the model is methodical one. It offers the combination of the flexible methods of management of programming procedure (benchmarking, foresight, crowdsourcing and outsourcing. The given model raises the efficiency of the management decisions of the state structures in the sphere of small business. Therefore, it is interesting for the government authorities, which are responsible for the regional and municipal support programs of small business, as well
A dialogue game approach to multi-agent system programming
Lebbink, Henk-Jan; Witteman, Cilia; Meyer, John-Jules Ch.
2004-01-01
This paper approaches multi-agent system programming with dialogue games allowing the semantics of communicative acts to be a component in multi-agent architectures. We present a dialogue game for enquiry enabling agents to answer questions in a distributed fashion. In addition, we propose a reasoning game that defines when agents are allowed to make decisions, in the current case, decisions to accept to believe propositions. These games are brought together in a deliberation cycle and are im...
An algebraic approach to analysis of recursive and concurrent programs
DEFF Research Database (Denmark)
Terepeta, Michal Tomasz
This thesis focuses on formal techniques based on static program analysis, model checking and abstract interpretation that offer means for reasoning about software, verification of its properties and discovering potential bugs. First, we investigate an algebraic approach to static analysis...... the soundness or completeness results. Moreover, we present a new application of pushdown systems in the context of an aspect-oriented process calculus. The addition of aspect-oriented features makes it possible for a process to exhibit a recursive structure. We show how one can faithfully model and analyze...... present a compact data structure as well as efficient algorithms for the semiring operations. Apart from that, we discuss an improvement to Pre* and Post* algorithms for pushdown systems, making it possible to directly use program representations such as program graphs. We present a modular library...
1991-01-01
A Science Definition Team was established in December 1990 by the Space Physics Division, NASA, to develop a satellite program to conduct research on the energetics, dynamics, and chemistry of the mesosphere and lower thermosphere/ionosphere. This two-volume publication describes the TIMED (Thermosphere-Ionosphere-Mesosphere, Energetics and Dynamics) mission and associated science program. The report outlines the scientific objectives of the mission, the program requirements, and the approach towards meeting these requirements.
Modelling dynamic programming problems by generalized d-graphs
Kátai, Zoltán
2010-01-01
In this paper we introduce the concept of generalized d-graph (admitting cycles) as special dependency-graphs for modelling dynamic programming (DP) problems. We describe the d-graph versions of three famous single-source shortest algorithms (The algorithm based on the topological order of the vertices, Dijkstra algorithm and Bellman-Ford algorithm), which can be viewed as general DP strategies in the case of three different class of optimization problems. The new modelling method also makes possible to classify DP problems and the corresponding DP strategies in term of graph theory.
Performance Potential-based Neuro-dynamic Programming for SMDPs
Institute of Scientific and Technical Information of China (English)
TANGHao; YUANJi-Bin; LUYang; CHENGWen-Juan
2005-01-01
An alpha-uniformized Markov chain is defined by the concept of equivalent infinitesimal generator for a semi-Markov decision process (SMDP) with both average- and discounted-criteria.According to the relations of their performance measures and performance potentials, the optimization of an SMDP can be realized by simulating the chain. For the critic model of neuro-dynamic programming (NDP), a neuro-policy iteration (NPI) algorithm is presented, and the performance error bound is shown as there are approximate error and improvement error in each iteration step.The obtained results may be extended to Markov systems, and have much applicability. Finally, a numerical example is provided.
Automatic cone photoreceptor segmentation using graph theory and dynamic programming.
Chiu, Stephanie J; Lokhnygina, Yuliya; Dubis, Adam M; Dubra, Alfredo; Carroll, Joseph; Izatt, Joseph A; Farsiu, Sina
2013-06-01
Geometrical analysis of the photoreceptor mosaic can reveal subclinical ocular pathologies. In this paper, we describe a fully automatic algorithm to identify and segment photoreceptors in adaptive optics ophthalmoscope images of the photoreceptor mosaic. This method is an extension of our previously described closed contour segmentation framework based on graph theory and dynamic programming (GTDP). We validated the performance of the proposed algorithm by comparing it to the state-of-the-art technique on a large data set consisting of over 200,000 cones and posted the results online. We found that the GTDP method achieved a higher detection rate, decreasing the cone miss rate by over a factor of five.
Dynamic programming and graph algorithms in computer vision.
Felzenszwalb, Pedro F; Zabih, Ramin
2011-04-01
Optimization is a powerful paradigm for expressing and solving problems in a wide range of areas, and has been successfully applied to many vision problems. Discrete optimization techniques are especially interesting since, by carefully exploiting problem structure, they often provide nontrivial guarantees concerning solution quality. In this paper, we review dynamic programming and graph algorithms, and discuss representative examples of how these discrete optimization techniques have been applied to some classical vision problems. We focus on the low-level vision problem of stereo, the mid-level problem of interactive object segmentation, and the high-level problem of model-based recognition.
Dynamic programming in in uence diagrams with decision circuits
Shachter, Ross D
2012-01-01
Decision circuits perform efficient evaluation of influence diagrams, building on the ad- vances in arithmetic circuits for belief net- work inference [Darwiche, 2003; Bhattachar- jya and Shachter, 2007]. We show how even more compact decision circuits can be con- structed for dynamic programming in influ- ence diagrams with separable value functions and conditionally independent subproblems. Once a decision circuit has been constructed based on the diagram's "global" graphical structure, it can be compiled to exploit "lo- cal" structure for efficient evaluation and sen- sitivity analysis.
Dynamic Programming and Graph Algorithms in Computer Vision*
Felzenszwalb, Pedro F.; Zabih, Ramin
2013-01-01
Optimization is a powerful paradigm for expressing and solving problems in a wide range of areas, and has been successfully applied to many vision problems. Discrete optimization techniques are especially interesting, since by carefully exploiting problem structure they often provide non-trivial guarantees concerning solution quality. In this paper we briefly review dynamic programming and graph algorithms, and discuss representative examples of how these discrete optimization techniques have been applied to some classical vision problems. We focus on the low-level vision problem of stereo; the mid-level problem of interactive object segmentation; and the high-level problem of model-based recognition. PMID:20660950
BRANECODE: A Program for Simulations of Braneworld Dynamics
Martin, Johannes; Frolov, Andrei V; Kofman, Lev; Peloso, Marco; Martin, Johannes; Felder, Gary N.; Frolov, Andrei V.; Kofman, Lev; Peloso, Marco
2004-01-01
We describe an algorithm and a C++ implementation that we have written and made available for calculating the fully nonlinear evolution of 5D braneworld models with scalar fields. Bulk fields allow for the stabilization of the extra space. However, they complicate the dynamics of the system, so that analytic calculations (performed within an effective 4D theory) are typically only reliable close to stabilized configurations or when the evolution of the extra space is negligible. In the general case, a numerical study of the 5D equations is necessary, and the algorithm and code we describe are the first ones designed for this task. The program and its full documentation are available on the Web at http://www.cita.utoronto.ca/~jmartin/BRANECODE/. In this paper we provide a brief overview of what the program does and how to use it.
Dynamics of the public concern and risk communication program implementation.
Zaryabova, Victoria; Israel, Michel
2015-09-01
The public concern about electromagnetic field (EMF) exposure varies due to different reasons. A part of them are connected with the better and higher quality of information that people receive from science, media, Internet, social networks, industry, but others are based on good communication programs performed by the responsible institutions, administration and persons. Especially, in Bulgaria, public concern follows interesting changes, some of them in correlation with the European processes of concern, but others following the economic and political processes in the country. Here, we analyze the dynamics of the public concern over the last 10 years. Our explanation of the decrease of the people's complaints against EMF exposure from base stations for mobile communication is as a result of our risk communication program that is in implementation for >10 years.
Linear-programming approach to electricity demand-curtailment planning
Energy Technology Data Exchange (ETDEWEB)
Allentuck, J; Carroll, O; Schnader, M
1980-05-01
Curtailment planning at a generally rudimentary level has been undertaken by the governments of some twenty states. Many utilities have demand-curtailment plans, however, these are often incorporated in plans for meeting capacity shortages. In at least five states, there are apparently no curtailment plans either at the state-government level or at the utility level. Moreover, none of the existing electricity demand curtailment plans examined included an explicit statement of the planners' objective in arriving at a specified sharing of the burdens of curtailment among consumer classes. Yet clearly the actual allocations of such burdens will affect the cost of the shortage. Since a study of state planning failed to yield a clear-cut indication of which of many possible curtailment allocation schemes would best serve as a point of departure for the design of an optimal curtailment strategy to deal with prolonged supply deficiencies, it was then decided to use a linear-programming approach. The advantages of such an approach are examined first, after which some important conceptual and practical problems in the design of a specific linear-programming model are addressed. A mathematical statement of the model is then followed by a brief review the principal methodological shortcomings of the linear-programming approach. Finally, the authors discuss how the analysis might be expanded to account for inter-regional and other secondary effects of curtailment.
A hierarchical state space approach to affective dynamics
Lodewyckx, Tom; Tuerlinckx, Francis; Kuppens, Peter; Allen, Nicholas; Sheeber, Lisa
2010-01-01
Linear dynamical system theory is a broad theoretical framework that has been applied in various research areas such as engineering, econometrics and recently in psychology. It quantifies the relations between observed inputs and outputs that are connected through a set of latent state variables. State space models are used to investigate the dynamical properties of these latent quantities. These models are especially of interest in the study of emotion dynamics, with the system representing the evolving emotion components of an individual. However, for simultaneous modeling of individual and population differences, a hierarchical extension of the basic state space model is necessary. Therefore, we introduce a Bayesian hierarchical model with random effects for the system parameters. Further, we apply our model to data that were collected using the Oregon adolescent interaction task: 66 normal and 67 depressed adolescents engaged in a conflict interaction with their parents and second-to-second physiological and behavioral measures were obtained. System parameters in normal and depressed adolescents were compared, which led to interesting discussions in the light of findings in recent literature on the links between cardiovascular processes, emotion dynamics and depression. We illustrate that our approach is flexible and general: The model can be applied to any time series for multiple systems (where a system can represent any entity) and moreover, one is free to focus on whatever component of the versatile model. PMID:21516216
New Sentinel-2 radiometric validation approaches (SEOM program)
Bruniquel, Véronique; Lamquin, Nicolas; Ferron, Stéphane; Govaerts, Yves; Woolliams, Emma; Dilo, Arta; Gascon, Ferran
2016-04-01
SEOM is an ESA program element whose one of the objectives aims at launching state-of-the-art studies for the scientific exploitation of operational missions. In the frame of this program, ESA awarded ACRI-ST and its partners Rayference and National Physical Laboratory (NPL) early 2016 for a R&D study on the development and intercomparison of algorithms for validating the Sentinel-2 radiometric L1 data products beyond the baseline algorithms used operationally in the frame of the S2 Mission Performance Centre. In this context, several algorithms have been proposed and are currently in development: The first one is based on the exploitation of Deep Convective Cloud (DCC) observations over ocean. This method allows an inter-band radiometry validation from the blue to the NIR (typically from B1 to B8a) from a reference band already validated for example with the well-known Rayleigh method. Due to their physical properties, DCCs appear from the remote sensing point of view to have bright and cold tops and they can be used as invariant targets to monitor the radiometric response degradation of reflective solar bands. The DCC approach is statistical i.e. the method shall be applied on a large number of measurements to derive reliable statistics and decrease the impact of the perturbing contributors. The second radiometric validation method is based on the exploitation of matchups combining both concomitant in-situ measurements and Sentinel-2 observations. The in-situ measurements which are used here correspond to measurements acquired in the frame of the RadCalNet networks. The validation is performed for the Sentinel-2 bands similar to the bands of the instruments equipping the validation site. The measurements from the Cimel CE 318 12-filters BRDF Sun Photometer installed recently in the Gobabeb site near the Namib desert are used for this method. A comprehensive verification of the calibration requires an analysis of MSI radiances over the full dynamic range
A temporal interpolation approach for dynamic reconstruction in perfusion CT.
Montes, Pau; Lauritsch, Günter
2007-07-01
This article presents a dynamic CT reconstruction algorithm for objects with time dependent attenuation coefficient. Projection data acquired over several rotations are interpreted as samples of a continuous signal. Based on this idea, a temporal interpolation approach is proposed which provides the maximum temporal resolution for a given rotational speed of the CT scanner. Interpolation is performed using polynomial splines. The algorithm can be adapted to slow signals, reducing the amount of data acquired and the computational cost. A theoretical analysis of the approximations made by the algorithm is provided. In simulation studies, the temporal interpolation approach is compared with three other dynamic reconstruction algorithms based on linear regression, linear interpolation, and generalized Parker weighting. The presented algorithm exhibits the highest temporal resolution for a given sampling interval. Hence, our approach needs less input data to achieve a certain quality in the reconstruction than the other algorithms discussed or, equivalently, less x-ray exposure and computational complexity. The proposed algorithm additionally allows the possibility of using slow rotating scanners for perfusion imaging purposes.
A Rational Approach to Ring Flexibility in Internal Coordinate Dynamics
Mazur, A K
1998-01-01
Internal coordinate molecular dynamics (ICMD) is an efficient method for studying biopolymers, but it is readily applicable only to molecules with tree topologies, that is with no internal flexible rings. Common examples violating this condition are prolines and loops closed by S-S bridges in proteins. The most important such case, however, is nucleic acids because the flexibility of the furanose rings always plays an essential role in conformational transitions both in DNA and RNA. There are a few long-known theoretical approaches to this problem, but, in practice, rings with fixed bond lengths are closed by adding appropriate harmonic distance restraints, which is not always acceptable especially in dynamics. This paper tries to overcome this handicap of ICMD and proposes a rational strategy which results in practical numerical algorithms. It gives a unified analytical treatment which shows that this problem is very close to the difficulties encountered by the method of constraints in Cartesian coordinate d...
Quantum Trajectory Approach to Molecular Dynamics Simulation with Surface Hopping
Feng, Wei; Li, Xin-Qi; Fang, Weihai
2012-01-01
The powerful molecular dynamics (MD) simulation is basically based on a picture that the atoms experience classical-like trajectories under the exertion of classical force field determined by the quantum mechanically solved electronic state. In this work we propose a quantum trajectory approach to the MD simulation with surface hopping, from an insight that an effective "observation" is actually implied in theMDsimulation through tracking the forces experienced, just like checking the meter's result in the quantum measurement process. This treatment can build the nonadiabatic surface hopping on a dynamical foundation, instead of the usual artificial and conceptually inconsistent hopping algorithms. The effects and advantages of the proposed scheme are preliminarily illustrated by a two-surface model system.
Information dynamics and open systems classical and quantum approach
Ingarden, R S; Ohya, M
1997-01-01
This book aims to present an information-theoretical approach to thermodynamics and its generalisations On the one hand, it generalises the concept of `information thermodynamics' to that of `information dynamics' in order to stress applications outside thermal phenomena On the other hand, it is a synthesis of the dynamics of state change and the theory of complexity, which provide a common framework to treat both physical and nonphysical systems together Both classical and quantum systems are discussed, and two appendices are included to explain principal definitions and some important aspects of the theory of Hilbert spaces and operator algebras The concept of higher-order temperatures is explained and applied to biological and linguistic systems The theory of open systems is presented in a new, much more general form Audience This volume is intended mainly for theoretical and mathematical physicists, but also for mathematicians, experimental physicists, physical chemists, theoretical biologists, communicat...
Optical resonance problem in metamaterial arrays: a lattice dynamics approach
Liu, Wanguo
2016-11-01
A systematic dynamic theory is established to deal with the optical collective resonance in metamaterial arrays. As a reference model, we consider an infinite split ring resonator (SRR) array illuminated by a linearly polarized wave and introduce an N-degree-of-freedom forced oscillator equation to simplify the coupled-mode vibration problem. We derive a strict formula of resonance frequency (RF) and its adjustable range from the steady-state response. Unlike a single SRR possesses invariant RF, it successfully explains the mechanism of RF shift effect in the SRR array when the incident angle changes. Instead of full wave analysis, only one or two adjacent resonance modes can give an accurate response line shape. Our approach is applicable for metallic arrays with any N-particle cell at all incident angles and well matched with numerical results. It provides a versatile way to study the vibration dynamics in optical periodic many-body systems.
Fault-tolerant quantum computation -- a dynamical systems approach
Fern, J; Simic, S; Sastry, S; Fern, Jesse; Kempe, Julia; Simic, Slobodan; Sastry, Shankar
2004-01-01
We apply a dynamical systems approach to concatenation of quantum error correcting codes, extending and generalizing the results of Rahn et al. [8] to both diagonal and nondiagonal channels. Our point of view is global: instead of focusing on particular types of noise channels, we study the geometry of the coding map as a discrete-time dynamical system on the entire space of noise channels. In the case of diagonal channels, we show that any code with distance at least three corrects (in the infinite concatenation limit) an open set of errors. For CSS codes, we give a more precise characterization of that set. We show how to incorporate noise in the gates, thus completing the framework. We derive some general bounds for noise channels, which allows us to analyze several codes in detail.
Fuzzy Decision-Making Approach in Geometric Programming for a Single Item EOQ Model
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Monalisha Pattnaik
2015-06-01
Full Text Available Background and methods: Fuzzy decision-making approach is allowed in geometric programming for a single item EOQ model with dynamic ordering cost and demand-dependent unit cost. The setup cost varies with the quantity produced/purchased and the modification of objective function with storage area in the presence of imprecisely estimated parameters are investigated. It incorporates all concepts of a fuzzy arithmetic approach, the quantity ordered, and demand per unit compares both fuzzy geometric programming technique and other models for linear membership functions. Results and conclusions: Investigation of the properties of an optimal solution allows developing an algorithm whose validity is illustrated through an example problem and the results discu ssed. Sensitivity analysis of the optimal solution is also studied with respect to changes in different parameter values.
A combined stochastic programming and optimal control approach to personal finance and pensions
DEFF Research Database (Denmark)
Konicz, Agnieszka Karolina; Pisinger, David; Rasmussen, Kourosh Marjani
2015-01-01
The paper presents a model that combines a dynamic programming (stochastic optimal control) approach and a multi-stage stochastic linear programming approach (SLP), integrated into one SLP formulation. Stochastic optimal control produces an optimal policy that is easy to understand and implement....... However, explicit solution may not exist, especially when we want to deal with constraints, such as the limits on the portfolio composition, the limits on the insured sum, an inclusion of transaction costs or taxes on capital gains, which are important issues regularly mentioned in the scientic literature....... Two applications are considered: (A) optimal investment, consumption and insured sum for an individual maximizing the expected utility of consumption and bequest, and (B) optimal investment for a pension saver who wishes to maximize the expected utility of retirement benets. Numerical results show...
Effects of Maternal Obesity on Fetal Programming: Molecular Approaches.
Neri, Caterina; Edlow, Andrea G
2015-09-03
Maternal obesity has become a worldwide epidemic. Obesity and a high-fat diet have been shown to have deleterious effects on fetal programming, predisposing offspring to adverse cardiometabolic and neurodevelopmental outcomes. Although large epidemiological studies have shown an association between maternal obesity and adverse outcomes for offspring, the underlying mechanisms remain unclear. Molecular approaches have played a key role in elucidating the mechanistic underpinnings of fetal malprogramming in the setting of maternal obesity. These approaches include, among others, characterization of epigenetic modifications, microRNA expression, the gut microbiome, the transcriptome, and evaluation of specific mRNA expression via quantitative reverse transcription polmerase chain reaction (RT-qPCR) in fetuses and offspring of obese females. This work will review the data from animal models and human fluids/cells regarding the effects of maternal obesity on fetal and offspring neurodevelopment and cardiometabolic outcomes, with a particular focus on molecular approaches.
Vibrational mechanics nonlinear dynamic effects, general approach, applications
Blekhman, Iliya I
2000-01-01
This important book deals with vibrational mechanics - the new, intensively developing section of nonlinear dynamics and the theory of nonlinear oscillations. It offers a general approach to the study of the effect of vibration on nonlinear mechanical systems.The book presents the mathematical apparatus of vibrational mechanics which is used to describe such nonlinear effects as the disappearance and appearance under vibration of stable positions of equilibrium and motions (i.e. attractors), the change of the rheological properties of the media, self-synchronization, self-balancing, the vibrat
Adiabatic hyperspherical approach to large-scale nuclear dynamics
Suzuki, Yasuyuki
2015-01-01
We formulate a fully microscopic approach to large-scale nuclear dynamics using a hyperradius as a collective coordinate. An adiabatic potential is defined by taking account of all possible configurations at a fixed hyperradius, and its hyperradius dependence plays a key role in governing the global nuclear motion. In order to go to larger systems beyond few-body systems, we suggest basis functions of a microscopic multicluster model, propose a method for calculating matrix elements of an adiabatic Hamiltonian with use of Fourier transforms, and test its effectiveness.
Phase-space approach to multi-population dynamics
Budko, Neil V
2015-01-01
Simultaneous deterministic dynamics of multiple populations described by a large set of ODE's is considered in the phase space of population sizes and ODE's parameters. The problem is formulated as a multidimensional phase-space conservation law and is solved explicitly for non-interacting multi-population models. Solutions for populations competing for a limited resource and populations with migration are obtained by simple iterative methods. The proposed approach also allows considering phase-space interaction between populations, which is intractable by other methods.
Dynamics of coupled field solitons: A collective coordinate approach
Indian Academy of Sciences (India)
Danial Saadatmand; Aliakbar Moradi Marjaneh; Mahdi Heidari
2014-10-01
In this paper we consider a class of systems of two coupled real scalar fields in bidimensional space-time, with the main motivation of studying classical stability of soliton solutions using collective coordinate approach. First, we present the class of systems of the collective coordinate equations which are derived using the presented method. After that, we follow the dynamics of the coupled fields with local inhomogeneity like a delta function potential wall as well as a delta function potential well. The results of the investigation of the two coupled fields are compared to each other and the differences are discussed. The method can predict most of the characters of the interaction.
An evolutionary computational approach for the dynamic Stackelberg competition problems
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Lorena Arboleda-Castro
2016-06-01
Full Text Available Stackelberg competition models are an important family of economical decision problems from game theory, in which the main goal is to find optimal strategies between two competitors taking into account their hierarchy relationship. Although these models have been widely studied in the past, it is important to note that very few works deal with uncertainty scenarios, especially those that vary over time. In this regard, the present research studies this topic and proposes a computational method for solving efficiently dynamic Stackelberg competition models. The computational experiments suggest that the proposed approach is effective for problems of this nature.
Approximate Dynamic Programming in Tracking Control of a Robotic Manipulator
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Marcin Szuster
2016-02-01
Full Text Available This article focuses on the implementation of an approximate dynamic programming algorithm in the discrete tracking control system of the three-degrees of freedom Scorbot-ER 4pc robotic manipulator. The controlled system is included in an articulated robots group which uses rotary joints to access their work space. The main part of the control system is a dual heuristic dynamic programming algorithm that consists of two structures designed in the form of neural networks: an actor and a critic. The actor generates the suboptimal control law while the critic approximates the difference of the value function from Bellman’s equation with respect to the state. The residual elements of the control system are the PD controller, the supervisory term and an additional control signal. The structure of the supervisory term derives from the stability analysis performed using the Lyapunov stability theorem. The control system works online, the neural networks’ weights-adaptation procedure is performed in every iteration step, and the neural networks’ preliminary learning process is not required. The performance of the control system was verified by a series of computer simulations and experiments performed using the Scorbot-ER 4pc robotic manipulator.
Dynamical system approach to running Λ cosmological models
Energy Technology Data Exchange (ETDEWEB)
Stachowski, Aleksander [Jagiellonian University, Astronomical Observatory, Krakow (Poland); Szydlowski, Marek [Jagiellonian University, Astronomical Observatory, Krakow (Poland); Jagiellonian University, Mark Kac Complex Systems Research Centre, Krakow (Poland)
2016-11-15
We study the dynamics of cosmological models with a time dependent cosmological term. We consider five classes of models; two with the non-covariant parametrization of the cosmological term Λ: Λ(H)CDM cosmologies, Λ(a)CDM cosmologies, and three with the covariant parametrization of Λ: Λ(R)CDM cosmologies, where R(t) is the Ricci scalar, Λ(φ)-cosmologies with diffusion, Λ(X)-cosmologies, where X = (1)/(2)g{sup αβ}∇{sub α}∇{sub β}φ is a kinetic part of the density of the scalar field. We also consider the case of an emergent Λ(a) relation obtained from the behaviour of trajectories in a neighbourhood of an invariant submanifold. In the study of the dynamics we used dynamical system methods for investigating how an evolutionary scenario can depend on the choice of special initial conditions. We show that the methods of dynamical systems allow one to investigate all admissible solutions of a running Λ cosmology for all initial conditions. We interpret Alcaniz and Lima's approach as a scaling cosmology. We formulate the idea of an emergent cosmological term derived directly from an approximation of the exact dynamics. We show that some non-covariant parametrization of the cosmological term like Λ(a), Λ(H) gives rise to the non-physical behaviour of trajectories in the phase space. This behaviour disappears if the term Λ(a) is emergent from the covariant parametrization. (orig.)
A Dynamic Bayesian Approach to Computational Laban Shape Quality Analysis
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Dilip Swaminathan
2009-01-01
kinesiology. LMA (especially Effort/Shape emphasizes how internal feelings and intentions govern the patterning of movement throughout the whole body. As we argue, a complex understanding of intention via LMA is necessary for human-computer interaction to become embodied in ways that resemble interaction in the physical world. We thus introduce a novel, flexible Bayesian fusion approach for identifying LMA Shape qualities from raw motion capture data in real time. The method uses a dynamic Bayesian network (DBN to fuse movement features across the body and across time and as we discuss can be readily adapted for low-cost video. It has delivered excellent performance in preliminary studies comprising improvisatory movements. Our approach has been incorporated in Response, a mixed-reality environment where users interact via natural, full-body human movement and enhance their bodily-kinesthetic awareness through immersive sound and light feedback, with applications to kinesiology training, Parkinson's patient rehabilitation, interactive dance, and many other areas.
Approach to Quantum Kramers' Equation and Barrier Crossing Dynamics
Banerjee, Dhruba; Banik, S K; Ray, D S; Banerjee, Dhruba; Bag, Bidhan Chandra; Banik, Suman Kumar; Ray, Deb Shankar
2002-01-01
We have presented a simple approach to quantum theory of Brownian motion and barrier crossing dynamics. Based on an initial coherent state representation of bath oscillators and an equilibrium canonical distribution of quantum mechanical mean values of their co-ordinates and momenta we have derived a $c$-number generalized quantum Langevin equation. The approach allows us to implement the method of classical non-Markovian Brownian motion to realize an exact generalized non-Markovian quantum Kramers' equation. The equation is valid for arbitrary temperature and friction. We have solved this equation in the spatial diffusion-limited regime to derive quantum Kramers' rate of barrier crossing and analyze its variation as a function of temperature and friction. While almost all the earlier theories rest on quasi-probability distribution functions (like Wigner function) and path integral methods, the present work is based on {\\it true probability distribution functions} and is independent of path integral technique...
Feature Fusion Approach on Keystroke Dynamics Efficiency Enhancement
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Pin Shen Teh
2015-05-01
Full Text Available In this paper we study the performance and effect of diverse keystroke feature combinations on keystroke dynamics authentication system by using fusion approach. First of all, four types of keystroke features are acquired from our collected dataset, later then transformed into similarity scores by using Gaussian Probability Density Function (GPD and Direction Similarity Measure (DSM. Next, three fusion approaches are introduced to merge the scores pairing with different combinations of fusion rules. Result shows that the finest performance is obtained by the combination of both dwell time and flight time collectively. Finally, this experiment also investigates the effect of using larger dataset on recognition performance, which turns out to be rather consistent.
Dynamic Analysis of a Helicopter Rotor by Dymore Program
Doğan, Vedat; Kırca, Mesut
The dynamic behavior of hingeless and bearingless blades of a light commercial helicopter which has been under design process at ITU (İstanbul Technical University, Rotorcraft Research and Development Centre) is investigated. Since the helicopter rotor consists of several parts connected to each other by joints and hinges; rotors in general can be considered as an assembly of the rigid and elastic parts. Dynamics of rotor system in rotation is complicated due to coupling of elastic forces (bending, torsion and tension), inertial forces, control and aerodynamic forces on the rotor blades. In this study, the dynamic behavior of the rotor for a real helicopter design project is analyzed by using DYMORE. Blades are modeled as elastic beams, hub as a rigid body, torque tubes as rigid bodies, control links as rigid bodies plus springs and several joints. Geometric and material cross-sectional properties of blades (Stiffness-Matrix and Mass-Matrix) are calculated by using VABS programs on a CATIA model. Natural frequencies and natural modes of the rotating (and non-rotating) blades are obtained by using DYMORE. Fan-Plots which show the variation of the natural frequencies for different modes (Lead-Lag, Flapping, Feathering, etc.) vs. rotor RPM are presented.
Fluid-Solid Interaction and Multiscale Dynamic Processes: Experimental Approach
Arciniega-Ceballos, Alejandra; Spina, Laura; Mendo-Pérez, Gerardo M.; Guzmán-Vázquez, Enrique; Scheu, Bettina; Sánchez-Sesma, Francisco J.; Dingwell, Donald B.
2017-04-01
. Analysis of time series, both experimental and synthetics, synchronized with high-speed imaging enables the explanation and interpretation of distinct phases of the dynamics of these fluids and the extraction of time and frequency characteristics of the individual processes. We observed that the effects of both, pressure drop triggering function and viscosity, control the characteristics of the micro-signals in time and frequency. This suggests the great potential that experimental and numerical approaches provide to untangle from field volcanic seismograms the multiscale processes of the stress field, driving forces and fluid-rock interaction that determine the volcanic conduit dynamics.
A linear programming approach for placement of applicants to academic programs.
Kassa, Biniyam Asmare
2013-01-01
This paper reports a linear programming approach for placement of applicants to study programs developed and implemented at the college of Business & Economics, Bahir Dar University, Bahir Dar, Ethiopia. The approach is estimated to significantly streamline the placement decision process at the college by reducing required man hour as well as the time it takes to announce placement decisions. Compared to the previous manual system where only one or two placement criteria were considered, the new approach allows the college's management to easily incorporate additional placement criteria, if needed. Comparison of our approach against manually constructed placement decisions based on actual data for the 2012/13 academic year suggested that about 93 percent of the placements from our model concur with the actual placement decisions. For the remaining 7 percent of placements, however, the actual placements made by the manual system display inconsistencies of decisions judged against the very criteria intended to guide placement decisions by the college's program management office. Overall, the new approach proves to be a significant improvement over the manual system in terms of efficiency of the placement process and the quality of placement decisions.
Dynamic optimization of complex program controlling the structure of an enterprise's product range
Directory of Open Access Journals (Sweden)
Andrey Fedorovich Shorikov
2012-09-01
Full Text Available This paper reviews a methodical approach to solving multi-step dynamic problem of optimal integrated program management of a product portfolio structure of the enterprise. Any multiproduct manufacturing process depends on many factors, that is why the quality criteria in theeconomic andmathematicalmodel of the dynamics of the product portfolio structuremanagement of a company is a vector one, and therefore, optimization of the integrated product portfolio structure management of a company is multi-criteria optimization problem. With the help of the method of generalized criterion (method of vectorcriterion scalarization, a formed multicriteria problem is replaced by a one-criterion optimization problem of complex management program of product portfolio structure with a functional of quality, which is a convolution of a set (vector of the objective functions. The transformed problem is formulated and solved as a problem of optimal terminal program control in a class of linear discrete dynamical systems. The method proposed in this paper allows developing management solutions designed to create the optimal structure of an enterprise's product lines, contributing to optimization of profits as well as maintenance of the desired level of profit for a long period of time
A Neurodynamic Optimization Approach to Bilevel Quadratic Programming.
Qin, Sitian; Le, Xinyi; Wang, Jun
2016-08-19
This paper presents a neurodynamic optimization approach to bilevel quadratic programming (BQP). Based on the Karush-Kuhn-Tucker (KKT) theorem, the BQP problem is reduced to a one-level mathematical program subject to complementarity constraints (MPCC). It is proved that the global solution of the MPCC is the minimal one of the optimal solutions to multiple convex optimization subproblems. A recurrent neural network is developed for solving these convex optimization subproblems. From any initial state, the state of the proposed neural network is convergent to an equilibrium point of the neural network, which is just the optimal solution of the convex optimization subproblem. Compared with existing recurrent neural networks for BQP, the proposed neural network is guaranteed for delivering the exact optimal solutions to any convex BQP problems. Moreover, it is proved that the proposed neural network for bilevel linear programming is convergent to an equilibrium point in finite time. Finally, three numerical examples are elaborated to substantiate the efficacy of the proposed approach.
Portfolio optimization in enhanced index tracking with goal programming approach
Siew, Lam Weng; Jaaman, Saiful Hafizah Hj.; Ismail, Hamizun bin
2014-09-01
Enhanced index tracking is a popular form of passive fund management in stock market. Enhanced index tracking aims to generate excess return over the return achieved by the market index without purchasing all of the stocks that make up the index. This can be done by establishing an optimal portfolio to maximize the mean return and minimize the risk. The objective of this paper is to determine the portfolio composition and performance using goal programming approach in enhanced index tracking and comparing it to the market index. Goal programming is a branch of multi-objective optimization which can handle decision problems that involve two different goals in enhanced index tracking, a trade-off between maximizing the mean return and minimizing the risk. The results of this study show that the optimal portfolio with goal programming approach is able to outperform the Malaysia market index which is FTSE Bursa Malaysia Kuala Lumpur Composite Index because of higher mean return and lower risk without purchasing all the stocks in the market index.
Fetal metabolic programming and epigenetic modifications: a systems biology approach.
Sookoian, Silvia; Gianotti, Tomas Fernández; Burgueño, Adriana L; Pirola, Carlos J
2013-04-01
A growing body of evidence supports the notion that epigenetic changes such as DNA methylation and histone modifications, both involving chromatin remodeling, contribute to fetal metabolic programming. We use a combination of gene-protein enrichment analysis resources along with functional annotations and protein interaction networks for an integrative approach to understanding the mechanisms underlying fetal metabolic programming. Systems biology approaches suggested that fetal adaptation to an impaired nutritional environment presumes profound changes in gene expression that involve regulation of tissue-specific patterns of methylated cytosine residues, modulation of the histone acetylation-deacetylation switch, cell differentiation, and stem cell pluripotency. The hypothalamus and the liver seem to be differently involved. In addition, new putative explanations have emerged about the question of whether in utero overnutrition modulates fetal metabolic programming in the same fashion as that of a maternal environment of undernutrition, suggesting that the mechanisms behind these two fetal nutritional imbalances are different. In conclusion, intrauterine growth restriction is most likely to be associated with the induction of persistent changes in tissue structure and functionality. Conversely, a maternal obesogenic environment is most probably associated with metabolic reprogramming of glucose and lipid metabolism, as well as future risk of metabolic syndrome (MS), fatty liver, and insulin (INS) resistance.
Energy Technology Data Exchange (ETDEWEB)
Kim, Jong Woo; Choi, Go Bong; Lee, Jong Min [Seoul National University, Seoul (Korea, Republic of); Suh, Jung Chul [Samchully Corporation, Seoul (Korea, Republic of)
2016-01-15
This paper proposes a Markov decision process (MDP) based approach to derive an optimal schedule of maintenance, rehabilitation and replacement of the water main system. The scheduling problem utilizes auxiliary information of a pipe such as the current state, cost, and deterioration model. The objective function and detailed algorithm of dynamic programming are modified to solve the periodic replacement problem. The optimal policy evaluated by the proposed algorithm is compared to several existing policies via Monte Carlo simulations. The proposed decision framework provides a systematic way to obtain an optimal policy.
Fugacity superposition: a new approach to dynamic multimedia fate modeling.
Hertwich, E G
2001-08-01
The fugacities, concentrations, or inventories of pollutants in environmental compartments as determined by multimedia environmental fate models of the Mackay type can be superimposed on each other. This is true for both steady-state (level III) and dynamic (level IV) models. Any problem in multimedia fate models with linear, time-invariant transfer and transformation coefficients can be solved through a superposition of a set of n independent solutions to a set of coupled, homogeneous first-order differential equations, where n is the number of compartments in the model. For initial condition problems in dynamic models, the initial inventories can be separated, e.g. by a compartment. The solution is obtained by adding the single-compartment solutions. For time-varying emissions, a convolution integral is used to superimpose solutions. The advantage of this approach is that the differential equations have to be solved only once. No numeric integration is required. Alternatively, the dynamic model can be simplified to algebraic equations using the Laplace transform. For time-varying emissions, the Laplace transform of the model equations is simply multiplied with the Laplace transform of the emission profile. It is also shown that the time-integrated inventories of the initial conditions problems are the same as the inventories in the steady-state problem. This implies that important properties of pollutants such as potential dose, persistence, and characteristic travel distance can be derived from the steady state.
Dynamical resource nexus assessments: from accounting to sustainability approaches
Salmoral, Gloria; Yan, Xiaoyu
2017-04-01
Continued economic development and population growth result in increasing pressures on natural resources, from local to international levels, for meeting societal demands on water, energy and food. To date there are a few tools that link models to identify the relationships and to account for flows of water, energy and food. However, these tools in general can offer only a static view often at national level and with annual temporal resolution. Moreover, they can only account flows but cannot consider the required amounts and conditions of the natural capital that supplies and maintains these flows. With the emerging nexus thinking, our research is currently focused on promoting dynamical environmental analyses beyond the conventional silo mentalities. Our study aims to show new advancements in existing tools (e.g., dynamical life cycle assessment) and develop novel environmental indicators relevant for the resource nexus assessment. We aim to provide a step forward when sustainability conditions and resilience thresholds are aligned with flows under production (e.g., food, water and energy), process level under analysis (e.g., local production, transport, manufacturing, final consumption, reuse, disposal) and existing biophysical local conditions. This approach would help to embrace and better characterise the spatiotemporal dynamics, complexity and existing links between and within the natural and societal systems, which are crucial to evaluate and promote more environmentally sustainable economic activities.
An innovative approach of risk planning for space programs.
Ray, P
2000-07-01
According to the current rule-based risk management approach at the National Aeronautics and Space Administration (NASA), the effort is directed to contain all identified risks of a program. The identification of hazards and mitigation effort proceeds along with the development of the system hardware, till all the tradable resources for a program is exhausted. In this process, no conscious effort is made to evaluate risks and associated cost, and the final design is likely to have undesirable residual risks. This approach also results in allocating a significant amount of resources to gain only marginal mitigation of hazard and leave some undesirable hazards in the system due to the budget limitation. The approach in the proposed knowledge-based risk planning system makes a conscious attempt to trade risk with other resources, e.g., schedule, cost, reliability, performance, and others in a judicious and cost-effective way. A knowledge of the feasible option sets requiring high incremental cost for a marginal gain in hazard reduction helps the management to make decision for residual risk that falls within an acceptable range for an option set.
A DYNAMIC APPROACH FOR RATE ADAPTATION IN MOBILE ADHOC NETWORKS
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Suganya Subramaniam
2013-01-01
Full Text Available A Mobile Ad hoc Network (MANET is a collection of mobile nodes with no fixed infrastructure. The absence of central authorization facility in dynamic and distributed environment affects the optimal utilization of resources like, throughput, power and bandwidth. Rate adaptation is the key technique to optimize the resource throughput. Some recently proposed rate adaptations use Request to Send/Clear to Send (RTS/CTS to suppress the collision effect by differentiating collisions from channel errors. This study presents a methodology to detect the misbehavior of nodes in MANET and proposed the new dynamic algorithm for rate adaptation which in turn can improve the throughput. The proposed approach is implemented in the distributed stipulating architecture with core and access routers. This method does not require additional probing overhead incurred by RTS/CTS exchanges and may be practically deployed without change in firmware. The collision and channel error occurrence will be detected by core router and intimated to the access router to choose alternate route and retain the current rate for transmission. The extensive simulation results demonstrate the effectiveness of proposed method by comparing with existing approaches.
A dynamic object-oriented architecture approach to ecosystem modeling and simulation.
Energy Technology Data Exchange (ETDEWEB)
Dolph, J. E.; Majerus, K. A.; Sydelko, P. J.; Taxon, T. N.
1999-04-09
Modeling and simulation in support of adaptive ecosystem management can be better accomplished through a dynamic, integrated, and flexible approach that incorporates scientific and technological components into a comprehensive ecosystem-modeling framework. The Integrated Dynamic Landscape Analysis and Modeling System (IDLAMS) integrates ecological models and decision support techniques, through a geographic information system (GIS)-based framework. The Strategic Environmental Research and Development Program (SERDP) sponsored the development of IDLAMS. Initially built upon a GIS framework, IDLAMS is migrating to an object-oriented (OO) architectural framework. An object-oriented architecture is more flexible and modular. It allows disparate applications and dynamic models to be integrated in a manner that minimizes (or eliminates) the need to rework or recreate the system as new models are added to the suite. In addition, an object-oriented design makes it easier to provide run-time feedback among models, thereby making it a more dynamic tool for exploring and providing insight into the interactions among ecosystem processes. Finally, an object-oriented design encourages the reuse of existing technology because OO-IDLAMS is able to integrate disparate models, databases, or applications executed in their native languages. Reuse is also accomplished through a structured approach to building a consistent and reusable object library. This reusability can substantially reduce the time and effort needed to develop future integrated ecosystem simulations.
Different approaches of symbolic dynamics to quantify heart rate complexity.
Cysarz, Dirk; Porta, Alberto; Montano, Nicola; Van Leeuwen, Peter; Kurths, Jürgen; Wessel, Niels
2013-01-01
The analysis of symbolic dynamics applied to physiological time series is able to retrieve information about dynamical properties of the underlying system that cannot be gained with standard methods like e.g. spectral analysis. Different approaches for the transformation of the original time series to the symbolic time series have been proposed. Yet the differences between the approaches are unknown. In this study three different transformation methods are investigated: (1) symbolization according to the deviation from the average time series, (2) symbolization according to several equidistant levels between the minimum and maximum of the time series, (3) binary symbolization of the first derivative of the time series. Each method was applied to the cardiac interbeat interval series RR(i) and its difference ΔRR(I) of 17 healthy subjects obtained during head-up tilt testing. The symbolic dynamics of each method is analyzed by means of the occurrence of short sequences ('words') of length 3. The occurrence of words is grouped according to words without variations of the symbols (0V%), words with one variation (1V%), two like variations (2LV%) and two unlike variations (2UV%). Linear regression analysis showed that for method 1 0V%, 1V%, 2LV% and 2UV% changed with increasing tilt angle. For method 2 0V%, 2LV% and 2UV% changed with increasing tilt angle and method 3 showed changes for 0V% and 1V%. In conclusion, all methods are capable of reflecting changes of the cardiac autonomic nervous system during head-up tilt. All methods show that even the analysis of very short symbolic sequences is capable of tracking changes of the cardiac autonomic regulation during head-up tilt testing.
A Constraint Programming Approach for Solving a Queueing Control Problem
Terekhov, Daria; 10.1613/jair.2446
2011-01-01
In a facility with front room and back room operations, it is useful to switch workers between the rooms in order to cope with changing customer demand. Assuming stochastic customer arrival and service times, we seek a policy for switching workers such that the expected customer waiting time is minimized while the expected back room staffing is sufficient to perform all work. Three novel constraint programming models and several shaving procedures for these models are presented. Experimental results show that a model based on closed-form expressions together with a combination of shaving procedures is the most efficient. This model is able to find and prove optimal solutions for many problem instances within a reasonable run-time. Previously, the only available approach was a heuristic algorithm. Furthermore, a hybrid method combining the heuristic and the best constraint programming method is shown to perform as well as the heuristic in terms of solution quality over time, while achieving the same performanc...
An Integer Programming Approach to Solving Tantrix on Fixed Boards
Directory of Open Access Journals (Sweden)
Yushi Uno
2012-03-01
Full Text Available Tantrix (Tantrix R ⃝ is a registered trademark of Colour of Strategy Ltd. in New Zealand, and of TANTRIX JAPAN in Japan, respectively, under the license of M. McManaway, the inventor. is a puzzle to make a loop by connecting lines drawn on hexagonal tiles, and the objective of this research is to solve it by a computer. For this purpose, we first give a problem setting of solving Tantrix as making a loop on a given fixed board. We then formulate it as an integer program by describing the rules of Tantrix as its constraints, and solve it by a mathematical programming solver to have a solution. As a result, we establish a formulation that can solve Tantrix of moderate size, and even when the solutions are invalid only by elementary constraints, we achieved it by introducing additional constraints and re-solve it. By this approach we succeeded to solve Tantrix of size up to 60.
Using Balanced Scorecard (BSC) approach to improve ergonomics programs.
Fernandes, Marcelo Vicente Forestieri
2012-01-01
The purpose of this paper is to propose foundations for a theory of using the Balanced Scorecard (BSC) methodology to improve the strategic view of ergonomics inside the organizations. This approach may help to promote a better understanding of investing on an ergonomic program to obtain good results in quality and production, as well as health maintenance. It is explained the basics of balanced scorecard, and how ergonomists could use this to work with strategic enterprises demand. Implications of this viewpoint for the development of a new methodology for ergonomics strategy views are offered.
Stochastic Control of Energy Efficient Buildings: A Semidefinite Programming Approach
Energy Technology Data Exchange (ETDEWEB)
Ma, Xiao [ORNL; Dong, Jin [ORNL; Djouadi, Seddik M [ORNL; Nutaro, James J [ORNL; Kuruganti, Teja [ORNL
2015-01-01
The key goal in energy efficient buildings is to reduce energy consumption of Heating, Ventilation, and Air- Conditioning (HVAC) systems while maintaining a comfortable temperature and humidity in the building. This paper proposes a novel stochastic control approach for achieving joint performance and power control of HVAC. We employ a constrained Stochastic Linear Quadratic Control (cSLQC) by minimizing a quadratic cost function with a disturbance assumed to be Gaussian. The problem is formulated to minimize the expected cost subject to a linear constraint and a probabilistic constraint. By using cSLQC, the problem is reduced to a semidefinite optimization problem, where the optimal control can be computed efficiently by Semidefinite programming (SDP). Simulation results are provided to demonstrate the effectiveness and power efficiency by utilizing the proposed control approach.
Mogo, César; Brandão, João
2014-06-30
READY (REActive DYnamics) is a program for studying reactive dynamic systems using a global potential energy surface (PES) built from previously existing PESs corresponding to each of the most important elementary reactions present in the system. We present an application to the combustion dynamics of a mixture of hydrogen and oxygen using accurate PESs for all the systems involving up to four oxygen and hydrogen atoms. Results at the temperature of 4000 K and pressure of 2 atm are presented and compared with model based on rate constants. Drawbacks and advantages of this approach are discussed and future directions of research are pointed out.
NEW METHOD FOR SHAPE RECOGNITION BASED ON DYNAMIC PROGRAMMING
Directory of Open Access Journals (Sweden)
NOREDINNE GHERABI
2011-02-01
Full Text Available In this paper we present a new method for shape recognition based on dynamic programming. First, each contour of shape is represented by a set of points. After alignment and matching between two shapes, the outline of the shape is divided into parts according to N angular and M radial sectors , Each Sector contains a portion of the contour; thisportion is divided at the inflexion points into convex and concave sections, and the information about sections are extracted in order to provide a semantic content to the outline shape, then this information are coded and transformed into a string of symbols. Finally we find the best alignment of two complete strings and compute the optimal cost of similarity. The algorithm has been tested on a large set of shape databases and real images (MPEG-7, natural silhouette database.
Estimating Arrhenius parameters using temperature programmed molecular dynamics
Imandi, Venkataramana; Chatterjee, Abhijit
2016-07-01
Kinetic rates at different temperatures and the associated Arrhenius parameters, whenever Arrhenius law is obeyed, are efficiently estimated by applying maximum likelihood analysis to waiting times collected using the temperature programmed molecular dynamics method. When transitions involving many activated pathways are available in the dataset, their rates may be calculated using the same collection of waiting times. Arrhenius behaviour is ascertained by comparing rates at the sampled temperatures with ones from the Arrhenius expression. Three prototype systems with corrugated energy landscapes, namely, solvated alanine dipeptide, diffusion at the metal-solvent interphase, and lithium diffusion in silicon, are studied to highlight various aspects of the method. The method becomes particularly appealing when the Arrhenius parameters can be used to find rates at low temperatures where transitions are rare. Systematic coarse-graining of states can further extend the time scales accessible to the method. Good estimates for the rate parameters are obtained with 500-1000 waiting times.
Novel algorithm for distributed replicas management based on dynamic programming
Institute of Scientific and Technical Information of China (English)
Wang Tao; Lu Xianliang; Hou Mengshu
2006-01-01
Replicas can improve the data reliability in distributed system. However, the traditional algorithms for replica management are based on the assumption that all replicas have the uniform reliability, which is inaccurate in some actual systems. To address such problem, a novel algorithm is proposed based on dynamic programming to manage the number and distribution of replicas in different nodes. By using Markov model, replicas management is organized as a multi-phase process, and the recursion equations are provided. In this algorithm, the heterogeneity of nodes, the expense for maintaining replicas and the engaged space have been considered. Under these restricted conditions, this algorithm realizes high data reliability in a distributed system. The results of case analysis prove the feasibility of the algorithm.
Dynamic programming algorithm for detecting dim infrared moving targets
He, Lisha; Mao, Liangjing; Xie, Lijun
2009-10-01
Infrared (IR) target detection is a key part of airborne infrared weapon system, especially the detection of poor dim moving IR target embedded in complex context. This paper presents an improved Dynamic Programming (DP) algorithm in allusion to low Signal to Noise Ratio (SNR) infrared dim moving targets under cluttered context. The algorithm brings the dim target to prominence by accumulating the energy of pixels in the image sequence, after suppressing the background noise with a mathematical morphology preprocessor. As considering the continuity and stabilization of target's energy and forward direction, this algorithm has well solved the energy scattering problem that exists in the original DP algorithm. An effective energy segmentation threshold is given by a Contrast-Limited Adaptive Histogram Equalization (CLAHE) filter with a regional peak extraction algorithm. Simulation results show that the improved DP tracking algorithm performs well in detecting poor dim targets.
Dispersion analysis techniques within the space vehicle dynamics simulation program
Snow, L. S.; Kuhn, A. E.
1975-01-01
The Space Vehicle Dynamics Simulation (SVDS) program was evaluated as a dispersion analysis tool. The Linear Error Analysis (LEA) post processor was examined in detail and simulation techniques relative to conducting a dispersion analysis using the SVDS were considered. The LEA processor is a tool for correlating trajectory dispersion data developed by simulating 3 sigma uncertainties as single error source cases. The processor combines trajectory and performance deviations by a root-sum-square (RSS process) and develops a covariance matrix for the deviations. Results are used in dispersion analyses for the baseline reference and orbiter flight test missions. As a part of this study, LEA results were verified as follows: (A) Hand calculating the RSS data and the elements of the covariance matrix for comparison with the LEA processor computed data. (B) Comparing results with previous error analyses. The LEA comparisons and verification are made at main engine cutoff (MECO).
Chimeric alignment by dynamic programming: Algorithm and biological uses
Energy Technology Data Exchange (ETDEWEB)
Komatsoulis, G.A.; Waterman, M.S. [Univ. of Southern California, Los Angeles, CA (United States)
1997-12-01
A new nearest-neighbor method for detecting chimeric 16S rRNA artifacts generated during PCR amplification from mixed populations has been developed. The method uses dynamic programming to generate an optimal chimeric alignment, defined as the highest scoring alignment between a query and a concatenation of a 5{prime} and a 3{prime} segment from two separate entries from a database of related sequences. Chimeras are detected by studying the scores and form of the chimeric and global sequence alignments. The chimeric alignment method was found to be marginally more effective than k-tuple based nearest-neighbor methods in simulation studies, but its most effective use is in concert with k-tuple methods. 15 refs., 3 figs., 1 tab.
Application of dynamic programming to structural repairing strategies
Institute of Scientific and Technical Information of China (English)
陈朝晖; LIU; Xila; 等
2002-01-01
A model of dynamic programming for repairing strategies of concrete structures during a projected service period is proposed,which takes into account the degradation in strength of components and the probability of accidental load.This model takes the safety grade of a structural system as the state variable of repairing strategies,and incorporates economic factors including expected repair cost,property loss due to structure failure,goods and material loss due to structure failure,loss of production interrupt due to structure failure,and inspection cost in decision making.It is found that the optimal repairing strategies are sensitive to the probability of accidental loads as well as the failure costs.The practicality of the model is demonstrated by an example.
Estimating Arrhenius parameters using temperature programmed molecular dynamics.
Imandi, Venkataramana; Chatterjee, Abhijit
2016-07-21
Kinetic rates at different temperatures and the associated Arrhenius parameters, whenever Arrhenius law is obeyed, are efficiently estimated by applying maximum likelihood analysis to waiting times collected using the temperature programmed molecular dynamics method. When transitions involving many activated pathways are available in the dataset, their rates may be calculated using the same collection of waiting times. Arrhenius behaviour is ascertained by comparing rates at the sampled temperatures with ones from the Arrhenius expression. Three prototype systems with corrugated energy landscapes, namely, solvated alanine dipeptide, diffusion at the metal-solvent interphase, and lithium diffusion in silicon, are studied to highlight various aspects of the method. The method becomes particularly appealing when the Arrhenius parameters can be used to find rates at low temperatures where transitions are rare. Systematic coarse-graining of states can further extend the time scales accessible to the method. Good estimates for the rate parameters are obtained with 500-1000 waiting times.
Dynamic programming on a tree for ultrasound elastography
Shams, Roozbeh; Boily, Mathieu; Martineau, Paul A.; Rivaz, Hassan
2016-04-01
Ultrasound Elastography is an emerging imaging technique that allows estimation of the mechanical characteristics of tissue. Two issues that need to be addressed before widespread use of elastography in clinical environments are real time constraints and deteriorating effects of signal decorrelation between pre- and post-compression images. Previous work has used Dynamic Programming (DP) to estimate tissue deformation. However, in case of large signal decorrelation, DP can fail. In this paper we, have proposed a novel solution to this problem by solving DP on a tree instead of a single Radio-Frequency line. Formulation of DP on a tree allows exploiting significantly more information, and as such, is more robust and accurate. Our results on phantom and in-vivo human data show that DP on tree significantly outperforms traditional DP in ultrasound elastography.
A system dynamics approach to understanding the One Health concept.
Xie, Tai; Liu, Wenbao; Anderson, Benjamin D; Liu, Xiaorong; Gray, Gregory C
2017-01-01
There have been many terms used to describe the One Health concept, including movement, strategy, framework, agenda, approach, among others. However, the inter-relationships of the disciplines engaged in the One Health concept have not been well described. To identify and better elucidate the internal feedback mechanisms of One Health, we employed a system dynamics approach. First, a systematic literature review was conducted via searches in PubMed, Web of Knowledge, and ProQuest with the search terms: 'One Health' and (concept* or approach*). In addition, we used the HistCite® tool to add significant articles on One Health to the library. Then, of the 2368 articles identified, 19 were selected for evaluating the inter-relationships of disciplines engaged in One Health. Herein, we report a visually rich, theoretical model regarding interactions of various disciplines and complex problem descriptors engaged in One Health problem solving. This report provides a conceptual framework for future descriptions of the interdisciplinary engagements involved in One Health.
General background and approach to multibody dynamics for space applications
Santini, Paolo; Gasbarri, Paolo
2009-06-01
Multibody dynamics for space applications is dictated by space environment such as space-varying gravity forces, orbital and attitude perturbations, control forces if any. Several methods and formulations devoted to the modeling of flexible bodies undergoing large overall motions were developed in recent years. Most of these different formulations were aimed to face one of the main problems concerning the analysis of spacecraft dynamics namely the reduction of computer simulation time. By virtue of this, the use of symbolic manipulation, recursive formulation and parallel processing algorithms were proposed. All these approaches fall into two categories, the one based on Newton/Euler methods and the one based on Lagrangian methods; both of them have their advantages and disadvantages although in general, Newtonian approaches lend to a better understanding of the physics of problems and in particular of the magnitude of the reactions and of the corresponding structural stresses. Another important issue which must be addressed carefully in multibody space dynamics is relevant to a correct choice of kinematics variables. In fact, when dealing with flexible multibody system the resulting equations include two different types of state variables, the ones associated with large (rigid) displacements and the ones associated with elastic deformations. These two sets of variables have generally two different time scales if we think of the attitude motion of a satellite whose period of oscillation, due to the gravity gradient effects, is of the same order of magnitude as the orbital period, which is much bigger than the one associated with the structural vibration of the satellite itself. Therefore, the numerical integration of the equations of the system represents a challenging problem. This was the abstract and some of the arguments that Professor Paolo Santini intended to present for the Breakwell Lecture; unfortunately a deadly disease attacked him and shortly took him
Design and Analysis of Decision Rules via Dynamic Programming
Amin, Talha M.
2017-04-24
The areas of machine learning, data mining, and knowledge representation have many different formats used to represent information. Decision rules, amongst these formats, are the most expressive and easily-understood by humans. In this thesis, we use dynamic programming to design decision rules and analyze them. The use of dynamic programming allows us to work with decision rules in ways that were previously only possible for brute force methods. Our algorithms allow us to describe the set of all rules for a given decision table. Further, we can perform multi-stage optimization by repeatedly reducing this set to only contain rules that are optimal with respect to selected criteria. One way that we apply this study is to generate small systems with short rules by simulating a greedy algorithm for the set cover problem. We also compare maximum path lengths (depth) of deterministic and non-deterministic decision trees (a non-deterministic decision tree is effectively a complete system of decision rules) with regards to Boolean functions. Another area of advancement is the presentation of algorithms for constructing Pareto optimal points for rules and rule systems. This allows us to study the existence of “totally optimal” decision rules (rules that are simultaneously optimal with regards to multiple criteria). We also utilize Pareto optimal points to compare and rate greedy heuristics with regards to two criteria at once. Another application of Pareto optimal points is the study of trade-offs between cost and uncertainty which allows us to find reasonable systems of decision rules that strike a balance between length and accuracy.
Directory of Open Access Journals (Sweden)
Jooyoung Park
2015-05-01
Full Text Available Recently, the optimization of power flows in portable hybrid power-supply systems (HPSSs has become an important issue with the advent of a variety of mobile systems and hybrid energy technologies. In this paper, a control strategy is considered for dynamically managing power flows in portable HPSSs employing batteries and supercapacitors. Our dynamic power management strategy utilizes the concept of approximate dynamic programming (ADP. ADP methods are important tools in the fields of stochastic control and machine learning, and the utilization of these tools for practical engineering problems is now an active and promising research field. We propose an ADP-based procedure based on optimization under constraints including the iterated Bellman inequalities, which can be solved by convex optimization carried out offline, to find the optimal power management rules for portable HPSSs. The effectiveness of the proposed procedure is tested through dynamic simulations for smartphone workload scenarios, and simulation results show that the proposed strategy can successfully cope with uncertain workload demands.
Lewis, F L; Vamvoudakis, Kyriakos G
2011-02-01
Approximate dynamic programming (ADP) is a class of reinforcement learning methods that have shown their importance in a variety of applications, including feedback control of dynamical systems. ADP generally requires full information about the system internal states, which is usually not available in practical situations. In this paper, we show how to implement ADP methods using only measured input/output data from the system. Linear dynamical systems with deterministic behavior are considered herein, which are systems of great interest in the control system community. In control system theory, these types of methods are referred to as output feedback (OPFB). The stochastic equivalent of the systems dealt with in this paper is a class of partially observable Markov decision processes. We develop both policy iteration and value iteration algorithms that converge to an optimal controller that requires only OPFB. It is shown that, similar to Q -learning, the new methods have the important advantage that knowledge of the system dynamics is not needed for the implementation of these learning algorithms or for the OPFB control. Only the order of the system, as well as an upper bound on its "observability index," must be known. The learned OPFB controller is in the form of a polynomial autoregressive moving-average controller that has equivalent performance with the optimal state variable feedback gain.
Stochastic dynamic programming applied to planning of robot grinding tasks
Energy Technology Data Exchange (ETDEWEB)
Brown, M.L. (Digital Equipment Corp., Shrewsbury, MA (United States)); Whitney, D.E. (Massachusetts Inst. of Technology, Cambridge, MA (United States))
1994-10-01
This paper proposes an intelligent manufacturing system that can make decisions about the process in light of the uncertain outcome of these decisions and attempts to minimize the expected economic penalty resulting from those decisions. It uses robot weld bead grinding as an example of a process with significant process variations. The need for multiple grinding passes, the poor predictability of those passes, the task requirements, and the process constraints conspire to make planning and controlling weld bead grinding a formidable probe. A three tier hierarchical control system is proposed to plan an optimal sequence of grinding passes, dynamically simulate each pass, execute the planned sequence of controlled grinding passes, and modify the pass sequence as grinding continues. The top tier, described in this paper, plans the grinding sequence for each weld bead, and is implemented using Stochastic Dynamic Programming, selecting the volumetric removal and feedspeed for each pass in order to optimize the satisfaction of the task requirements by the entire grinding sequence within the equipment, task, and process constraints. The resulting optimal policies have quite complex structures, showing foresight, anxiety, indifference, and aggressiveness, depending upon the situation.
Hamiltonian-Driven Adaptive Dynamic Programming for Continuous Nonlinear Dynamical Systems.
Yang, Yongliang; Wunsch, Donald; Yin, Yixin
2017-02-01
This paper presents a Hamiltonian-driven framework of adaptive dynamic programming (ADP) for continuous time nonlinear systems, which consists of evaluation of an admissible control, comparison between two different admissible policies with respect to the corresponding the performance function, and the performance improvement of an admissible control. It is showed that the Hamiltonian can serve as the temporal difference for continuous-time systems. In the Hamiltonian-driven ADP, the critic network is trained to output the value gradient. Then, the inner product between the critic and the system dynamics produces the value derivative. Under some conditions, the minimization of the Hamiltonian functional is equivalent to the value function approximation. An iterative algorithm starting from an arbitrary admissible control is presented for the optimal control approximation with its convergence proof. The implementation is accomplished by a neural network approximation. Two simulation studies demonstrate the effectiveness of Hamiltonian-driven ADP.
A DC programming approach for finding communities in networks.
Le Thi, Hoai An; Nguyen, Manh Cuong; Dinh, Tao Pham
2014-12-01
Automatic discovery of community structures in complex networks is a fundamental task in many disciplines, including physics, biology, and the social sciences. The most used criterion for characterizing the existence of a community structure in a network is modularity, a quantitative measure proposed by Newman and Girvan (2004). The discovery community can be formulated as the so-called modularity maximization problem that consists of finding a partition of nodes of a network with the highest modularity. In this letter, we propose a fast and scalable algorithm called DCAM, based on DC (difference of convex function) programming and DCA (DC algorithms), an innovative approach in nonconvex programming framework for solving the modularity maximization problem. The special structure of the problem considered here has been well exploited to get an inexpensive DCA scheme that requires only a matrix-vector product at each iteration. Starting with a very large number of communities, DCAM furnishes, as output results, an optimal partition together with the optimal number of communities [Formula: see text]; that is, the number of communities is discovered automatically during DCAM's iterations. Numerical experiments are performed on a variety of real-world network data sets with up to 4,194,304 nodes and 30,359,198 edges. The comparative results with height reference algorithms show that the proposed approach outperforms them not only on quality and rapidity but also on scalability. Moreover, it realizes a very good trade-off between the quality of solutions and the run time.
Directory of Open Access Journals (Sweden)
Bruno H. Dias
2010-01-01
Full Text Available This paper presents a new approach for the expected cost-to-go functions modeling used in the stochastic dynamic programming (SDP algorithm. The SDP technique is applied to the long-term operation planning of electrical power systems. Using state space discretization, the Convex Hull algorithm is used for constructing a series of hyperplanes that composes a convex set. These planes represent a piecewise linear approximation for the expected cost-to-go functions. The mean operational costs for using the proposed methodology were compared with those from the deterministic dual dynamic problem in a case study, considering a single inflow scenario. This sensitivity analysis shows the convergence of both methods and is used to determine the minimum discretization level. Additionally, the applicability of the proposed methodology for two hydroplants in a cascade is demonstrated. With proper adaptations, this work can be extended to a complete hydrothermal system.
Maiti, Sumit Kumar; Roy, Sankar Kumar
2016-05-01
In this paper, a Multi-Choice Stochastic Bi-Level Programming Problem (MCSBLPP) is considered where all the parameters of constraints are followed by normal distribution. The cost coefficients of the objective functions are multi-choice types. At first, all the probabilistic constraints are transformed into deterministic constraints using stochastic programming approach. Further, a general transformation technique with the help of binary variables is used to transform the multi-choice type cost coefficients of the objective functions of Decision Makers(DMs). Then the transformed problem is considered as a deterministic multi-choice bi-level programming problem. Finally, a numerical example is presented to illustrate the usefulness of the paper.
A Dynamical Systems Approach to Geodesics in Bianchi Cosmologies
Nilsson, Ulf S.; Uggla, Claes; Wainwright, John
2000-10-01
To understand the observational properties of cosmological models, in particular, the temperature of the cosmic microwave background radiation, it is necessary to study their null geodesics. Dynamical systems theory, in conjunction with the orthonormal frame approach, has proved to be an invaluable tool for analyzing spatially homogeneous cosmologies. It is thus natural to use such techniques to study the geodesics of these models. We therefore augment the Einstein field equations with the geodesic equations, all written in dimensionless form, obtaining an extended system of first-order ordinary differential equations that simultaneously describes the evolution of the gravitational field and the behavior of the associated geodesics. It is shown that the extended system is a powerful tool for investigating the effect of space-time anisotropies on the temperature of the cosmic microwave background radiation, and that it can also be used for studying geodesic chaos.
Description of dynamics of stock prices by a Langevin approach
Institute of Scientific and Technical Information of China (English)
Huang Zi-Gang; Chen Yong; Zhang Yong; Wang Ying-Hai
2007-01-01
We have studied the Langevin description of stochastic dynamics of financial time series. A sliding-window algorithm is used for our analysis. We find that the fluctuation of stock prices can be understood from the view of a time-dependent drift force corresponding to the drift parameter in Langevin equation. It is revealed that the statistical results of the drift force estimated from financial time series can be approximately considered as a linear restoring force. We investigate the significance of this linear restoring force to the prices evolution from its two coefficients, the equilibrium position and the slope coefficient. The daily log-returns of S&P 500 index from 1950 to 1999 are especially analysed. The new simple form of the restoring force obtained both from mathematical and numerical analyses suggests that the Langevin approach can effectively present not only the macroscopical but also the detailed properties of the price evolution.
A New Fuzzy Approach for Dynamic Load Balancing Algorithm
Karimi, Abbas; Jantan, Adznan b; Ramli, A R; Saripan, M Iqbal b
2009-01-01
Load balancing is the process of improving the Performance of a parallel and distributed system through is distribution of load among the processors [1-2]. Most of the previous work in load balancing and distributed decision making in general, do not effectively take into account the uncertainty and inconsistency in state information but in fuzzy logic, we have advantage of using crisps inputs. In this paper, we present a new approach for implementing dynamic load balancing algorithm with fuzzy logic, which can face to uncertainty and inconsistency of previous algorithms, further more our algorithm shows better response time than round robin and randomize algorithm respectively 30.84 percent and 45.45 percent.
A New Fuzzy Approach for Dynamic Load Balancing Algorithm
Directory of Open Access Journals (Sweden)
Abbas Karimi
2009-10-01
Full Text Available Load balancing is the process of improving the Performance of a parallel and distributed system through is distribution of load among the processors [1-2]. Most of the previous work in load balancing and distributed decision making in general, do not effectively take into account the uncertainty and inconsistency in state information but in fuzzy logic, we have advantage of using crisps inputs. In this paper,we present a new approach for implementing dynamic load balancing algorithm with fuzzy logic, which can face to uncertainty and inconsistency of previous algorithms, further more our algorithm shows better response time than round robin and randomize algorithm respectively 30.84% and 45.45%.
Dynamics analysis on neural firing patterns by symbolic approach
Institute of Scientific and Technical Information of China (English)
Gao Zhi-Ying; Lu Qi-Shao
2007-01-01
Neural firing patterns are investigated by using symbolic dynamics. Bifurcation behaviour of the Hindmarsh-Rose (HR) neuronal model is simulated with the external stimuli gradually decreasing, and various firing activities with different topological structures are orderly numbered. Through constructing first-return maps of interspike intervals, all firing patterns are described and identified by symbolic expressions. On the basis of ordering rules of symbolic sequences, the corresponding relation between parameters and firing patterns is established, which will be helpful for encoding neural information. Moreover, using the operation rule of * product, generation mechanisms and intrinsic configurations of periodic patterns can be distinguished in detail. Results show that the symbolic approach is a powerful tool to study neural firing activities. In particular, such a coarse-grained way can be generalized in neural electrophysiological experiments to extract much valuable information from complicated experimental data.
Citation analysis: A social and dynamic approach to knowledge organization
DEFF Research Database (Denmark)
Hjørland, Birger
2013-01-01
be considered superior for all purposes. The main difference between traditional knowledge organization systems (KOSs) and maps based on citation analysis is that the first group represents intellectual KOSs, whereas the second represents social KOSs. For this reason bibliometric maps cannot be expected ever......Knowledge organization (KO) and bibliometrics have traditionally been seen as separate subfields of library and information science, but bibliometric techniques make it possible to identify candidate terms for thesauri and to organize knowledge by relating scientific papers and authors to each...... a distinct approach to KO which is characterized by its social, historical and dynamic nature, its close dependence on scholarly literature and its explicit kind of literary warrant. The two main methods, co-citation analysis and bibliographic coupling represent different things and thus neither can...
Analytic and probabilistic approaches to dynamics in negative curvature
Peigné, Marc; Sambusetti, Andrea
2014-01-01
The work of E. Hopf and G.A. Hedlund, in the 1930s, on transitivity and ergodicity of the geodesic flow for hyperbolic surfaces, marked the beginning of the investigation of the statistical properties and stochastic behavior of the flow. The first central limit theorem for the geodesic flow was proved in the 1960s by Y. Sinai for compact hyperbolic manifolds. Since then, strong relationships have been found between the fields of ergodic theory, analysis, and geometry. Different approaches and new tools have been developed to study the geodesic flow, including measure theory, thermodynamic formalism, transfer operators, Laplace operators, and Brownian motion. All these different points of view have led to a deep understanding of more general dynamical systems, in particular the so-called Anosov systems, with applications to geometric problems such as counting, equirepartition, mixing, and recurrence properties of the orbits. This book comprises two independent texts that provide a self-contained introduction t...
Environmental Radiation Effects on Mammals A Dynamical Modeling Approach
Smirnova, Olga A
2010-01-01
This text is devoted to the theoretical studies of radiation effects on mammals. It uses the framework of developed deterministic mathematical models to investigate the effects of both acute and chronic irradiation in a wide range of doses and dose rates on vital body systems including hematopoiesis, small intestine and humoral immunity, as well as on the development of autoimmune diseases. Thus, these models can contribute to the development of the system and quantitative approaches in radiation biology and ecology. This text is also of practical use. Its modeling studies of the dynamics of granulocytopoiesis and thrombocytopoiesis in humans testify to the efficiency of employment of the developed models in the investigation and prediction of radiation effects on these hematopoietic lines. These models, as well as the properly identified models of other vital body systems, could provide a better understanding of the radiation risks to health. The modeling predictions will enable the implementation of more ef...
Dynamic Line Rating Oncor Electric Delivery Smart Grid Program
Energy Technology Data Exchange (ETDEWEB)
Johnson, Justin; Smith, Cale; Young, Mike; Donohoo, Ken; Owen, Ross; Clark, Eddit; Espejo, Raul; Aivaliotis, Sandy; Stelmak, Ron; Mohr, Ron; Barba, Cristian; Gonzalez, Guillermo; Malkin, Stuart; Dimitrova, Vessela; Ragsdale, Gary; Mitchem, Sean; Jeirath, Nakul; Loomis, Joe; Trevino, Gerardo; Syracuse, Steve; Hurst, Neil; Mereness, Matt; Johnson, Chad; Bivens, Carrie
2013-05-04
Electric transmission lines are the lifeline of the electric utility industry, delivering its product from source to consumer. This critical infrastructure is often constrained such that there is inadequate capacity on existing transmission lines to efficiently deliver the power to meet demand in certain areas or to transport energy from high-generation areas to high-consumption regions. When this happens, the cost of the energy rises; more costly sources of power are used to meet the demand or the system operates less reliably. These economic impacts are known as congestion, and they can amount to substantial dollars for any time frame of reference: hour, day or year. There are several solutions to the transmission constraint problem, including: construction of new generation, construction of new transmission facilities, rebuilding and reconductoring of existing transmission assets, and Dynamic Line Rating (DLR). All of these options except DLR are capital intensive, have long lead times and often experience strong public and regulatory opposition. The Smart Grid Demonstration Program (SGDP) project co-funded by the Department of Energy (DOE) and Oncor Electric Delivery Company developed and deployed the most extensive and advanced DLR installation to demonstrate that DLR technology is capable of resolving many transmission capacity constraint problems with a system that is reliable, safe and very cost competitive. The SGDP DLR deployment is the first application of DLR technology to feed transmission line real-time dynamic ratings directly into the system operation’s State Estimator and load dispatch program, which optimizes the matching of generation with load demand on a security, reliability and economic basis. The integrated Dynamic Line Rating (iDLR)1 collects transmission line parameters at remote locations on the lines, calculates the real-time line rating based on the equivalent conductor temperature, ambient temperature and influence of wind and solar
A uniform approach for programming distributed heterogeneous computing systems.
Grasso, Ivan; Pellegrini, Simone; Cosenza, Biagio; Fahringer, Thomas
2014-12-01
Large-scale compute clusters of heterogeneous nodes equipped with multi-core CPUs and GPUs are getting increasingly popular in the scientific community. However, such systems require a combination of different programming paradigms making application development very challenging. In this article we introduce libWater, a library-based extension of the OpenCL programming model that simplifies the development of heterogeneous distributed applications. libWater consists of a simple interface, which is a transparent abstraction of the underlying distributed architecture, offering advanced features such as inter-context and inter-node device synchronization. It provides a runtime system which tracks dependency information enforced by event synchronization to dynamically build a DAG of commands, on which we automatically apply two optimizations: collective communication pattern detection and device-host-device copy removal. We assess libWater's performance in three compute clusters available from the Vienna Scientific Cluster, the Barcelona Supercomputing Center and the University of Innsbruck, demonstrating improved performance and scaling with different test applications and configurations.
DEFF Research Database (Denmark)
Negendahl, Kristoffer
affect the design process and collaboration between building designers and simulationists. Within the limits of applying the approach of Consequence based design to five case studies, followed by documentation based on interviews, surveys and project related documentations derived from internal reports...... that secures validity and quality assurance with a simulationist while sustaining autonomous control of building design with the building designer. Consequence based design is defined by the specific use of integrated dynamic models. These models include the parametric capabilities of a visual programming tool...... relies on various advancements in the area of integrated dynamic models. It also relies on the application and test of the approach in practice to evaluate the Consequence based design and the use of integrated dynamic models. As a result, the Consequence based design approach has been applied in five...
Braverman, Marc T.
2016-01-01
Extension program evaluations often present opportunities to analyze data in multiple ways. This article suggests that program evaluations can involve more sophisticated data analysis approaches than are often used. On the basis of a hypothetical program scenario and corresponding data set, two approaches to testing for evidence of program impact…
A Dynamic Approach to Modeling Dependence Between Human Failure Events
Energy Technology Data Exchange (ETDEWEB)
Boring, Ronald Laurids [Idaho National Laboratory
2015-09-01
In practice, most HRA methods use direct dependence from THERP—the notion that error be- gets error, and one human failure event (HFE) may increase the likelihood of subsequent HFEs. In this paper, we approach dependence from a simulation perspective in which the effects of human errors are dynamically modeled. There are three key concepts that play into this modeling: (1) Errors are driven by performance shaping factors (PSFs). In this context, the error propagation is not a result of the presence of an HFE yielding overall increases in subsequent HFEs. Rather, it is shared PSFs that cause dependence. (2) PSFs have qualities of lag and latency. These two qualities are not currently considered in HRA methods that use PSFs. Yet, to model the effects of PSFs, it is not simply a matter of identifying the discrete effects of a particular PSF on performance. The effects of PSFs must be considered temporally, as the PSFs will have a range of effects across the event sequence. (3) Finally, there is the concept of error spilling. When PSFs are activated, they not only have temporal effects but also lateral effects on other PSFs, leading to emergent errors. This paper presents the framework for tying together these dynamic dependence concepts.
Flow Equation Approach to the Statistics of Nonlinear Dynamical Systems
Marston, J. B.; Hastings, M. B.
2005-03-01
The probability distribution function of non-linear dynamical systems is governed by a linear framework that resembles quantum many-body theory, in which stochastic forcing and/or averaging over initial conditions play the role of non-zero . Besides the well-known Fokker-Planck approach, there is a related Hopf functional methodootnotetextUriel Frisch, Turbulence: The Legacy of A. N. Kolmogorov (Cambridge University Press, 1995) chapter 9.5.; in both formalisms, zero modes of linear operators describe the stationary non-equilibrium statistics. To access the statistics, we investigate the method of continuous unitary transformationsootnotetextS. D. Glazek and K. G. Wilson, Phys. Rev. D 48, 5863 (1993); Phys. Rev. D 49, 4214 (1994). (also known as the flow equation approachootnotetextF. Wegner, Ann. Phys. 3, 77 (1994).), suitably generalized to the diagonalization of non-Hermitian matrices. Comparison to the more traditional cumulant expansion method is illustrated with low-dimensional attractors. The treatment of high-dimensional dynamical systems is also discussed.
A COMPARATIVE ANALYSIS OF ASEAN CURRENCIES USING A COPULA APPROACH AND A DYNAMIC COPULA APPROACH
Directory of Open Access Journals (Sweden)
CHUKIAT CHAIBOONSRI
2012-12-01
Full Text Available The ASEAN Economic Community (AEC will be shaped developing to be a single market and production base in 2015, moving towards regional Economic Integration, 2009. These developments in international financial markets do lead to some adverse cost for AEC country borrowers. The specific objective aims to investigate the dependent measures and the co-movement among selected ASEAN currencies. A Copula Approach was used to examine dependent measures of Thai Baht exchange rate among selected ASEAN currencies during the period of 2008-2011. Also, a Dynamic Copula Approach was tested to investigate the co-movement of Thai Baht exchange rate among selected ASEAN currencies during the period of 2008-2011. The results of the study based on a Pearson linear correlation coefficient confirmed that Thai Baht exchange rate and each of selected ASEAN currencies have a linear correlation during the specific period excluding Vietnam exchange rate. Furthermore, based on empirical Copula Approach, Thai Baht exchange rate had a dependent structure with each of the selected in ASEAN currencies including Brunei exchange rate, Singapore exchange rate, Malaysia exchange rate, Indonesia exchange rate, Philippine exchange rate, and Vietnam exchange rate respectively. The results of Dynamic Copula estimation indicated that Thai Baht exchange rate had a co-movement with selected ASEAN currencies. The research results provide an informative and interactive ASEAN financial market to all users, including Global financial market.
Dynamic Programming Approaches for the Traveling Salesman Problem with Drone
P. Bouman (Paul); N.A.H. Agatz (Niels); M.E. Schmidt (Marie)
2017-01-01
markdownabstractA promising new delivery model involves the use of a delivery truck that collaborates with a drone to make deliveries. Effectively combining a drone and a truck gives rise to a new planning problem that is known as the Traveling Salesman Problem with Drone (TSP-D). This paper
A Static Greedy and Dynamic Adaptive Thread Spawning Approach for Loop-Level Parallelism
Institute of Scientific and Technical Information of China (English)
李美蓉; 赵银亮; 陶悠; 王启明
2014-01-01
Thread-level speculation becomes more attractive for the exploitation of thread-level parallelism from irregular sequential applications. But it is common for speculative threads to fail to reach the expected parallel performance. The reason is that the performance of speculative threads is extremely complicated by the fact that it not only suffers from the imprecision of compiler-directed performance estimation due to ambiguous control and data dependences, but also depends on the underlying hardware configuration and program behaviors. Thus, this paper proposes a statically greedy and dynamically adaptive approach for loop-level speculation to dynamically determine the best loop level at runtime. It relies on the compiler to select and optimize all loop candidates greedily, which are then proceeded on the cost-benefit analysis of different loop nesting levels for the determination of the order of loop speculation. Under the runtime loop execution prediction, we dynamically schedule and update the order of loop speculation, and ensure the best loop level to be always parallelized. Two different policies are also examined to maximize overall performance. Compared with traditional static loop selection techniques, our approach can achieve comparable or better performance.
A new approach to barrier-top fission dynamics
Bertsch, G. F.; Mehlhaff, J. M.
2016-06-01
We proposed a calculational framework for describing induced fission that avoids the Bohr-Wheeler assumption of well-defined fission channels. The building blocks of our approach are configurations that form a discrete, orthogonal basis and can be characterized by both energy and shape. The dynamics is to be determined by interaction matrix elements between the states rather than by a Hill-Wheeler construction of a collective coordinate. Within our approach, several simple limits can be seen: diffusion; quantized conductance; and ordinary decay through channels. The specific proposal for the discrete basis is to use the Kπ quantum numbers of the axially symmetric Hartree-Fock approximation to generate the configurations. Fission paths would be determined by hopping from configuration to configuration via the residual interaction. We show as an example the configurations needed to describe a fictitious fission decay 32S → 16 O + 16 O. We also examine the geometry of the path for fission of 236U, measuring distances by the number of jumps needed to go to a new Kπ partition.
Inertial Manifold and Large Deviations Approach to Reduced PDE Dynamics
Cardin, Franco; Favretti, Marco; Lovison, Alberto
2017-09-01
In this paper a certain type of reaction-diffusion equation—similar to the Allen-Cahn equation—is the starting point for setting up a genuine thermodynamic reduction i.e. involving a finite number of parameters or collective variables of the initial system. We firstly operate a finite Lyapunov-Schmidt reduction of the cited reaction-diffusion equation when reformulated as a variational problem. In this way we gain a finite-dimensional ODE description of the initial system which preserves the gradient structure of the original one and that is exact for the static case and only approximate for the dynamic case. Our main concern is how to deal with this approximate reduced description of the initial PDE. To start with, we note that our approximate reduced ODE is similar to the approximate inertial manifold introduced by Temam and coworkers for Navier-Stokes equations. As a second approach, we take into account the uncertainty (loss of information) introduced with the above mentioned approximate reduction by considering the stochastic version of the ODE. We study this reduced stochastic system using classical tools from large deviations, viscosity solutions and weak KAM Hamilton-Jacobi theory. In the last part we suggest a possible use of a result of our approach in the comprehensive treatment non equilibrium thermodynamics given by Macroscopic Fluctuation Theory.
Knowledge representation and rule-based solution system for dynamic programming model
Institute of Scientific and Technical Information of China (English)
胡祥培; 王旭茵
2003-01-01
A knowledge representation has been proposed using the state-space theory of Artificial Intelligencefor Dynamic Programming Model, in which a model can be defined as a six-tuple M = (I,G,O,T,D,S). Abuilding block modeling method uses the modules of a six-tuple to form a rule-based solution model. Moreover,a rule-based system has been designed and set up to solve the Dynamic Programming Model. This knowledge-based representation can be easily used to express symbolical knowledge and dynamic characteristics for Dynam-ic Programming Model, and the inference based on the knowledge in the process of solving Dynamic Program-ming Model can also be conveniently realized in computer.
Dynamic Programming and Error Estimates for Stochastic Control Problems with Maximum Cost
Energy Technology Data Exchange (ETDEWEB)
Bokanowski, Olivier, E-mail: boka@math.jussieu.fr [Laboratoire Jacques-Louis Lions, Université Paris-Diderot (Paris 7) UFR de Mathématiques - Bât. Sophie Germain (France); Picarelli, Athena, E-mail: athena.picarelli@inria.fr [Projet Commands, INRIA Saclay & ENSTA ParisTech (France); Zidani, Hasnaa, E-mail: hasnaa.zidani@ensta.fr [Unité de Mathématiques appliquées (UMA), ENSTA ParisTech (France)
2015-02-15
This work is concerned with stochastic optimal control for a running maximum cost. A direct approach based on dynamic programming techniques is studied leading to the characterization of the value function as the unique viscosity solution of a second order Hamilton–Jacobi–Bellman (HJB) equation with an oblique derivative boundary condition. A general numerical scheme is proposed and a convergence result is provided. Error estimates are obtained for the semi-Lagrangian scheme. These results can apply to the case of lookback options in finance. Moreover, optimal control problems with maximum cost arise in the characterization of the reachable sets for a system of controlled stochastic differential equations. Some numerical simulations on examples of reachable analysis are included to illustrate our approach.
Speed improvement of B-snake algorithm using dynamic programming optimization.
Charfi, Maher; Zrida, Jalel
2011-10-01
This paper presents a novel approach to contour approximation carried out by means of the B-snake algorithm and the dynamic programming (DP) optimization technique. Using the proposed strategy for contour point search procedure, computing complexity is reduced to O(N×M(2)), whereas the standard DP method has an O(N×M(4)) complexity, with N being the number of contour sample points and M being the number of candidates in the search space. The storage requirement was also decreased from N×M(3) to N×M memory elements. Some experiments on noise corrupted synthetic image, magnetic resonance, and computer tomography medical images have shown that the proposed approach results are equivalent to those obtained by the standard DP algorithm.
A Dynamic Economic Dispatch Model Incorporating Wind Power Based on Chance Constrained Programming
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Wushan Cheng
2014-12-01
Full Text Available In order to maintain the stability and security of the power system, the uncertainty and intermittency of wind power must be taken into account in economic dispatch (ED problems. In this paper, a dynamic economic dispatch (DED model based on chance constrained programming is presented and an improved particle swarm optimization (PSO approach is proposed to solve the problem. Wind power is regarded as a random variable and is included in the chance constraint. New formulation of up and down spinning reserve constraints are presented under expectation meaning. The improved PSO algorithm combines a feasible region adjustment strategy with a hill climbing search operation based on the basic PSO. Simulations are performed under three distinct test systems with different generators. Results show that both the proposed DED model and the improved PSO approach are effective.
Fang, Chao; Wu, Guo-Zhen
2010-01-01
The vibrational dynamics of HOCl and HOBr between bending and OCl/OBr stretching coordinates with anharmonicity and Fermi coupling is studied with the classical dynamical potential approach. The quantal vibrational dynamics is mostly mapped out by the classical nonlinear variables such as fixed points, except for the state energies, which are quantized. This approach is global in the sense that the focus is on a set of levels instead of individual ones. The dynamics of HOBr is demonstrated to be less complicated. The localized modes along the OCl/OBr stretching coordinates are also shown to have O-Br bonds more prone to dissociation.
Quantum Dynamical Behaviour in Complex Systems - A Semiclassical Approach
Energy Technology Data Exchange (ETDEWEB)
Ananth, Nandini [Univ. of California, Berkeley, CA (United States)
2008-01-01
systems is described. We proposed the use of a semiclassical correction term to a preliminary quantum calculation using, for instance, a variational approach. This allows us to increase the accuracy significantly. Modeling Nonadiabatic dynamics has always been a challenge to classical simulations because the multi-state nature of the dynamics cannot be described accurately by the time evolution on a single average surface, as is the classical approach. We show that using the Meyer-Miller-Stock-Thoss (MMST) representation of the exact vibronic Hamiltonian in combination with the IVR allows us to accurately describe dynamics where the non Born-Oppenheimer regime. One final problem that we address is that of extending this method to the long time regime. We propose the use of a time independent sampling function in the Monte Carlo integration over the phase space of initial trajectory conditions. This allows us to better choose the regions of importance at the various points in time; by using more trajectories in the important regions, we show that the integration can be converged much easier. An algorithm based loosely on the methods of Diffusion Monte Carlo is developed that allows us to carry out this time dependent sampling in a most efficient manner.
A type-driven approach to concrete meta programming.
Vinju, J.J.
2005-01-01
Applications that manipulate programs as data are called meta programs. Examples of meta programs are compilers, source-to-source translators and code generators. Meta programming can be supported by the ability to represent program fragments in concrete syntax instead of abstract syntax. The result
Ostrowski, M; Paulevé, L; Schaub, T; Siegel, A; Guziolowski, C
2016-11-01
Boolean networks (and more general logic models) are useful frameworks to study signal transduction across multiple pathways. Logic models can be learned from a prior knowledge network structure and multiplex phosphoproteomics data. However, most efficient and scalable training methods focus on the comparison of two time-points and assume that the system has reached an early steady state. In this paper, we generalize such a learning procedure to take into account the time series traces of phosphoproteomics data in order to discriminate Boolean networks according to their transient dynamics. To that end, we identify a necessary condition that must be satisfied by the dynamics of a Boolean network to be consistent with a discretized time series trace. Based on this condition, we use Answer Set Programming to compute an over-approximation of the set of Boolean networks which fit best with experimental data and provide the corresponding encodings. Combined with model-checking approaches, we end up with a global learning algorithm. Our approach is able to learn logic models with a true positive rate higher than 78% in two case studies of mammalian signaling networks; for a larger case study, our method provides optimal answers after 7min of computation. We quantified the gain in our method predictions precision compared to learning approaches based on static data. Finally, as an application, our method proposes erroneous time-points in the time series data with respect to the optimal learned logic models.
A computational toy model for shallow landslides: Molecular dynamics approach
Martelloni, Gianluca; Bagnoli, Franco; Massaro, Emanuele
2013-09-01
The aim of this paper is to propose a 2D computational algorithm for modeling the triggering and propagation of shallow landslides caused by rainfall. We used a molecular dynamics (MD) approach, similar to the discrete element method (DEM), that is suitable to model granular material and to observe the trajectory of a single particle, so to possibly identify its dynamical properties. We consider that the triggering of shallow landslides is caused by the decrease of the static friction along the sliding surface due to water infiltration by rainfall. Thence the triggering is caused by the two following conditions: (a) a threshold speed of the particles and (b) a condition on the static friction, between the particles and the slope surface, based on the Mohr-Coulomb failure criterion. The latter static condition is used in the geotechnical model to estimate the possibility of landslide triggering. The interaction force between particles is modeled, in the absence of experimental data, by means of a potential similar to the Lennard-Jones one. The viscosity is also introduced in the model and for a large range of values of the model's parameters, we observe a characteristic velocity pattern, with acceleration increments, typical of real landslides. The results of simulations are quite promising: the energy and time triggering distribution of local avalanches show a power law distribution, analogous to the observed Gutenberg-Richter and Omori power law distributions for earthquakes. Finally, it is possible to apply the method of the inverse surface displacement velocity [4] for predicting the failure time.
Wetlands for Wastewater: a Visual Approach to Microbial Dynamics
Joubert, L.; Wolfaardt, G.; Du Plessis, K.
2007-12-01
The complex character of distillery wastewater comprises high concentrations of sugars, lignins, hemicelluloses, dextrans, resins, polyphenols and organic acids which are recalcitrant to biodegradation. Microorganisms play a key role in the production and degradation of organic matter, environmental pollutants, and cycling of nutrients and metals. Due to their short life cycles microbes respond rapidly to external nutrient loading, with major consequences for the stability of biological systems. We evaluated the feasibility of wetlands to treat winery and distillery effluents in experimental systems based on constructed wetlands, including down-scaled on-site distillery wetlands, small-scale controlled greenhouse systems, and bench-scale mesocosms. Chemical, visual and molecular fingerprinting (t-RFLP) techniques were applied to study the dynamics of planktonic and attached (biofilm) communities at various points in wetlands of different size, retention time and geological substrate, and under influence of shock nutrient loadings. Variable- Pressure Scanning Electron Microscopy (VP-SEM) was applied to visualize microbial colonization, morphotype diversity and distribution, and 3D biofilm architecture. Cross-taxon and predator-prey interactions were markedly influenced by organic loading, while the presence of algae affected microbial community composition and biofilm structure. COD removal varied with geological substrate, and was positively correlated with retention time in gravel wetlands. Planktonic and biofilm communities varied markedly in different regions of the wetland and over time, as indicated by whole-community t-RFLP and VP-SEM. An integrative visual approach to community dynamics enhanced data retrieval not afforded by molecular techniques alone. The high microbial diversity along spatial and temporal gradients, and responsiveness to the physico-chemical environment, suggest that microbial communities maintain metabolic function by modifying species
Kim, Jae G.; Liu, Hanli
2008-01-01
We have developed dynamic tumor vascular phantoms and utilized them to investigate the biphasic behavior of increases in light absorption, which is directly associated with oxygenated hemoglobin concentration that was observed in vivo from rat breast tumor experiments during carbogen/oxygen inhalation. The experimental setup for the phantom study included a continuous-wave, multichannel, near-infrared spectroscopy (NIRS) system and syringe pumps to drive the simulated blood through the dynamic vascular phantoms. The results from such phantom experiments clearly show that the two time constants observed in tumor oxygenation dynamics in vivo can result from two different perfusion rates or two different blood flow velocities. We provide experimental support for our previous hypothesis: the biphasic tumor hemodynamic feature stems from a well-perfused and poorly perfused region that could be detected with the two time constants of the NIRS signals. With a multichannel approach, noninvasive NIRS measurements may have useful and prognostic values to quantify the therapeutic effects of cancer treatments.
Organic and inorganic nitrogen dynamics in soil - advanced Ntrace approach
Andresen, Louise C.; Björsne, Anna-Karin; Bodé, Samuel; Klemedtsson, Leif; Boeckx, Pascal; Rütting, Tobias
2016-04-01
Depolymerization of soil organic nitrogen (SON) into monomers (e.g. amino acids) is currently thought to be the rate limiting step for the terrestrial nitrogen (N) cycle. The production of free amino acids (AA) is followed by AA mineralization to ammonium, which is an important fraction of the total N mineralization. Accurate assessment of depolymerization and AA mineralization rate is important for a better understanding of the rate limiting steps. Recent developments in the 15N pool dilution techniques, based on 15N labelling of AA's, allow quantifying gross rates of SON depolymerization and AA mineralization (Wanek et al., 2010; Andersen et al., 2015) in addition to gross N mineralization. However, it is well known that the 15N pool dilution approach has limitations; in particular that gross rates of consumption processes (e.g. AA mineralization) are overestimated. This has consequences for evaluating the rate limiting step of the N cycle, as well as for estimating the nitrogen use efficiency (NUE). Here we present a novel 15N tracing approach, which combines 15N-AA labelling with an advanced version of the 15N tracing model Ntrace (Müller et al., 2007) explicitly accounting for AA turnover in soil. This approach (1) provides a more robust quantification of gross depolymerization and AA mineralization and (2) suggests a more realistic estimate for the microbial NUE of amino acids. Advantages of the new 15N tracing approach will be discussed and further improvements will be identified. References: Andresen, L.C., Bodé, S., Tietema, A., Boeckx, P., and Rütting, T.: Amino acid and N mineralization dynamics in heathland soil after long-term warming and repetitive drought, SOIL, 1, 341-349, 2015. Müller, C., Rütting, T., Kattge, J., Laughlin, R. J., and Stevens, R. J.: Estimation of parameters in complex 15N tracing models via Monte Carlo sampling, Soil Biology & Biochemistry, 39, 715-726, 2007. Wanek, W., Mooshammer, M., Blöchl, A., Hanreich, A., and Richter
Directory of Open Access Journals (Sweden)
Jila Naeini
2015-03-01
Full Text Available The aim of this study was to examine and compare the impact of two Dynamic Assessment (DA approaches, that is, Feuerstein’s Mediated Learning Experience (MLE and Brown’s Graduated Prompt (GP on Iranian EFL learners’ reading comprehension. Therefore, a mixed methods approach consisting of a semi-structured interview, a pretest, an intervention program, a posttest, and a transfer test was applied to assess and compare the efficacy of two DA approaches. One hundred and two EFL learners taking a General English course at Islamic Azad University were assigned to two experimental groups (MLEG and GPG and one comparison group (CG. The participants in the MLEG took part in the MLE, and the participants in the GPG participated in the GP intervention program. The results of the qualitative as well as the aggregate and disaggregated quantitative data analyses indicated that both intervention approaches of DA were effective in enhancing the learners’ reading comprehension.
Between Oais and Agile a Dynamic Data Management Approach
Bennett, V. L.; Conway, E. A.; Waterfall, A. M.; Pepler, S.
2015-12-01
In this paper we decribe an approach to the integration of existing archival activities which lies between compliance with the more rigid OAIS/TRAC standards and a more flexible "Agile" approach to the curation and preservation of Earth Observation data. We provide a high level overview of existing practice and discuss how these procedures can be extended and supported through the description of preservation state. The aim of which is to facilitate the dynamic controlled management of scientific data through its lifecycle. While processes are considered they are not statically defined but rather driven by human interactions in the form of risk management/review procedure that produce actionable plans, which are responsive to change. We then proceed by describing the feasibility testing of extended risk management and planning procedures which integrate current practices. This was done through the CEDA Archival Format Audit which inspected British Atmospheric Data Centre and NERC Earth Observation Data Centre Archival holdings. These holdings are extensive, comprising of around 2 Petabytes of data and 137 million individual files, which were analysed and characterised in terms of format, based risk. We are then able to present an overview of the format based risk burden faced by a large scale archive attempting to maintain the usability of heterogeneous environmental data sets We continue by presenting a dynamic data management information model and provide discussion of the following core model entities and their relationships: Aspirational entities, which include Data Entity definitions and their associated Preservation Objectives. Risk entities, which act as drivers for change within the data lifecycle. These include Acquisitional Risks, Technical Risks, Strategic Risks and External Risks Plan entities, which detail the actions to bring about change within an archive. These include Acquisition Plans, Preservation Plans and Monitoring plans which support
A Rapid Grid Search Method for Solving Dynamic Programming Problems in Economics
Hui He; Hao Zhang
2013-01-01
We introduce a rapid grid search method in solving dynamic programming problems in economics. Compared to mainstream grid search methods, by using local information of the Bellman equation, this method can significantly increase the efficiency in solving dynamic programming problems by reducing the grid points searched in the control space.
A Note on a Rapid Grid Search Method for Solving Dynamic Programming Problems in Economics
Hui He; Hao Zhang
2010-01-01
We introduce a rapid grid search method in solving the dynamic programming problems in economics. Compared to mainstream grid search methods, by using local information of the Bellman equation, this method can significantly increase the efficiency in solving dynamic programming problems by reducing the grid points searched in the control space.
A stochastic dynamic programming model for stream water quality management
Indian Academy of Sciences (India)
P P Mujumdar; Pavan Saxena
2004-10-01
This paper deals with development of a seasonal fraction-removal policy model for waste load allocation in streams addressing uncertainties due to randomness and fuzziness. A stochastic dynamic programming (SDP) model is developed to arrive at the steady-state seasonal fraction-removal policy. A fuzzy decision model (FDM) developed by us in an earlier study is used to compute the system performance measure required in the SDP model. The state of the system in a season is deﬁned by streamﬂows at the headwaters during the season and the initial DO deﬁcit at some pre-speciﬁed checkpoints. The random variation of streamﬂows is included in the SDP model through seasonal transitional probabilities. The decision vector consists of seasonal fraction-removal levels for the efﬂuent dischargers. Uncertainty due to imprecision (fuzziness) associated with water quality goals is addressed using the concept of fuzzy decision. Responses of pollution control agencies to the resulting end-of-season DO deﬁcit vector and that of dischargers to the fraction-removal levels are treated as fuzzy, and modelled with appropriate membership functions. Application of the model is illustrated with a case study of the Tungabhadra river in India.
Dynamic Programming Using Polar Variance for Image Segmentation.
Rosado-Toro, Jose A; Altbach, Maria I; Rodriguez, Jeffrey J
2016-10-06
When using polar dynamic programming (PDP) for image segmentation, the object size is one of the main features used. This is because if size is left unconstrained the final segmentation may include high-gradient regions that are not associated with the object. In this paper, we propose a new feature, polar variance, which allows the algorithm to segment objects of different sizes without the need for training data. The polar variance is the variance in a polar region between a user-selected origin and a pixel we want to analyze. We also incorporate a new technique that allows PDP to segment complex shapes by finding low-gradient regions and growing them. The experimental analysis consisted on comparing our technique with different active contour segmentation techniques on a series of tests. The tests consisted on robustness to additive Gaussian noise, segmentation accuracy with different grayscale images and finally robustness to algorithm-specific parameters. Experimental results show that our technique performs favorably when compared to other segmentation techniques.
Optimization of conventional water treatment plant using dynamic programming.
Mostafa, Khezri Seyed; Bahareh, Ghafari; Elahe, Dadvar; Pegah, Dadras
2015-12-01
In this research, the mathematical models, indicating the capability of various units, such as rapid mixing, coagulation and flocculation, sedimentation, and the rapid sand filtration are used. Moreover, cost functions were used for the formulation of conventional water and wastewater treatment plant by applying Clark's formula (Clark, 1982). Also, by applying dynamic programming algorithm, it is easy to design a conventional treatment system with minimal cost. The application of the model for a case reduced the annual cost. This reduction was approximately in the range of 4.5-9.5% considering variable limitations. Sensitivity analysis and prediction of system's feedbacks were performed for different alterations in proportion from parameters optimized amounts. The results indicated (1) that the objective function is more sensitive to design flow rate (Q), (2) the variations in the alum dosage (A), and (3) the sand filter head loss (H). Increasing the inflow by 20%, the total annual cost would increase to about 12.6%, while 20% reduction in inflow leads to 15.2% decrease in the total annual cost. Similarly, 20% increase in alum dosage causes 7.1% increase in the total annual cost, while 20% decrease results in 7.9% decrease in the total annual cost. Furthermore, the pressure decrease causes 2.95 and 3.39% increase and decrease in total annual cost of treatment plants.
Dynamic Programming and Genetic Algorithm for Business Processes Optimisation
Directory of Open Access Journals (Sweden)
Mateusz Wibig
2012-12-01
Full Text Available There are many business process modelling techniques, which allow to capture features of those processes, but graphical, diagrammatic models seems to be used most in companies and organizations. Although the modelling notations are more and more mature and can be used not only to visualise the process idea but also to implement it in the workflow solution and although modern software allows us to gather a lot of data for analysis purposes, there is still not much commercial used business process optimisation methods. In this paper the scheduling / optimisation method for automatic task scheduling in business processes models is described. The Petri Net model is used, but it can be easily applied to any other modelling notation, where the process is presented as a set of tasks, i.e. BPMN (Business Process Modelling Notation. The method uses Petri Nets’, business processes’ scalability and dynamic programming concept to reduce the necessary computations, by revising only those parts of the model, to which the change was applied.
Directory of Open Access Journals (Sweden)
Yang Song
2015-05-01
Full Text Available Purpose: The exactly and precisely supply of carrying spare parts has a crucial impact on support and could improve the performance of equipment. Spare parts support is the crux work which will be limited by spare parts allocation and support cost input. Reasonable support strategy can help in making good use of available resources and support the equipment in normal operational status. The purpose of this paper is to propose a dynamics model of spare parts support process based on considering the interaction of multiple factors, and explores the regulation of dynamics behavior in the system. In order to achieve the optimization strategy to improve the effect of support so that will enhance the relevant support parameters of equipment. Design/methodology/approach: Meditate the feedback relationship among some important factors of support that involve support cost, support time and maintenance ability. System dynamics theory is adopted to propose a dynamics model of spare parts support process, on the analysis of multiple factors and casual relationship to find some major ones which have crucial impact on spare parts support. Spare parts support cost and availability was regarded as the control objective, moreover, adjust the control paramours and improve the effect of cannibalization and lateral supply scheduling strategy for spares support. Findings: The factors of spare parts supply, demand and maintenance have relationship of control feedback, and adjust the value of some crucial factors can reduce the support cost and improve the availability value. The main finding is that adopting cannibalization strategy under condition of available materials can relieve the mission and operational availability decline caused by shortage of spare parts. Combining the lateral supply and cannibalization strategy can reduce the inventory of warship carrying spare parts. Practical implications: By controlling the value of key factors regarding aspect of spare
Munneke, M.; Jong, Z. de; Zwinderman, A.H.; Jansen, A.; Ronday, H.K.; Peter, W.F.H.; Boonman, D.C.G.; Ende, C.H.M. van den; Vliet Vlieland, T.P.M.; Hazes, J.M.W.
2003-01-01
OBJECTIVE: To evaluate adherence and satisfaction of patients with rheumatoid arthritis (RA) in a long-term intensive dynamic exercise program. METHODS: A total of 146 RA patients started an intensive (strength and endurance training for 75 minutes, twice a week, for 2 years) exercise program (Rheum
A New Approach to Programming Language Education for Beginners with Top-Down Learning
Directory of Open Access Journals (Sweden)
Daisuke Saito
2013-12-01
Full Text Available There are two basic approaches in learning new programming language: a bottom-up approach and a top-down approach. It has been said that if a learner has already acquired one language, the top-down approach is more efficient to learn another while, for a person who has absolutely no knowledge of any programming languages; the bottom-up approach is preferable. The major problem of the bottom-up approach is that it requires longer period to acquire the language. For quicker learning, this paper applies a top-down approach for a beginners who has not yet acquired any programming languages.
Navigating towards Decoupled Aquaponic Systems: A System Dynamics Design Approach
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Simon Goddek
2016-07-01
Full Text Available The classical working principle of aquaponics is to provide nutrient-rich aquacultural water to a hydroponic plant culture unit, which in turn depurates the water that is returned to the aquaculture tanks. A known drawback is that a compromise away from optimal growing conditions for plants and fish must be achieved to produce both crops and fish in the same environmental conditions. The objective of this study was to develop a theoretical concept of a decoupled aquaponic system (DAPS, and predict water, nutrient (N and P, fish, sludge, and plant levels. This has been approached by developing a dynamic aquaponic system model, using inputs from data found in literature covering the fields of aquaculture, hydroponics, and sludge treatment. The outputs from the model showed the dependency of aquacultural water quality on the hydroponic evapotranspiration rate. This result can be explained by the fact that DAPS is based on one-way flows. These one-way flows results in accumulations of remineralized nutrients in the hydroponic component ensuring optimal conditions for the plants. The study also suggests to size the cultivation area based on P availability in the hydroponic component as P is an exhaustible resource and has been identified one of the main limiting factors for plant growth.
On the polynomial dynamic system approach to software development
Institute of Scientific and Technical Information of China (English)
WANG Xiangyun; LI Yongchao; CAI Kaiyuan
2004-01-01
In this paper the development of reactive software is transformed into a control problem, and the supervisory control theory for discrete event dynamic systems is suggested to solve this control problem. The operating environment under consideration is viewed as a controlled plant, the software under development as the corresponding controller, and the software requirements as the corresponding control objective. This idea leads to a constructive approach of software design, which ensures properties required a priori of the software under development. In this way the validation of the software under development is reduced to the validation of properties independent of implementation process. We reveal the inconsistence in using the concept of reachability to specify software requirements and clarify six different definitions of reachability. Two different definitions of invariance for specifying software requirements are also clarified.We then show how to synthesize the required controller or obtain software design solutions if the underlying software requirements are specified by several new combinations of reachability and invariance. The topic of this paper falls into the scope of software cybernetics that explores the interplay between software and control.
Dynamic Query Optimization Approach for Semantic Database Grid
Institute of Scientific and Technical Information of China (English)
Xiao-Qing Zheng; Hua-Jun Chen; Zhao-Hui Wu; Yu-Xin Mao
2006-01-01
Fundamentally, semantic grid database is about bringing globally distributed databases together in order to coordinate resource sharing and problem solving in which information is given well-defined meaning, and DartGrid Ⅱ is the implemented database gird system whose goal is to provide a semantic solution for integrating database resources on the Web.Although many algorithms have been proposed for optimizing query-processing in order to minimize costs and/or response time, associated with obtaining the answer to query in a distributed database system, database grid query optimization problem is fundamentally different from traditional distributed query optimization. These differences are shown to be the consequences of autonomy and heterogeneity of database nodes in database grid. Therefore, more challenges have arisen for query optimization in database grid than traditional distributed database. Following this observation, the design of a query optimizer in DartGrid Ⅱ is presented, and a heuristic, dynamic and parallel query optimization approach to processing query in database grid is proposed. A set of semantic tools supporting relational database integration and semantic-based information browsing has also been implemented to realize the above vision.
Dynamic energy budget approaches for modelling organismal ageing.
van Leeuwen, Ingeborg M M; Vera, Julio; Wolkenhauer, Olaf
2010-11-12
Ageing is a complex multifactorial process involving a progressive physiological decline that, ultimately, leads to the death of an organism. It involves multiple changes in many components that play fundamental roles under healthy and pathological conditions. Simultaneously, every organism undergoes accumulative 'wear and tear' during its lifespan, which confounds the effects of the ageing process. The scenario is complicated even further by the presence of both age-dependent and age-independent competing causes of death. Various manipulations have been shown to interfere with the ageing process. Calorie restriction, for example, has been reported to increase the lifespan of a wide range of organisms, which suggests a strong relation between energy metabolism and ageing. Such a link is also supported within the main theories for ageing: the free radical hypothesis, for instance, links oxidative damage production directly to energy metabolism. The Dynamic Energy Budgets (DEB) theory, which characterizes the uptake and use of energy by living organisms, therefore constitutes a useful tool for gaining insight into the ageing process. Here we compare the existing DEB-based modelling approaches and, then, discuss how new biological evidence could be incorporated within a DEB framework.
Dynamical system approach to scalar-vector-tensor cosmology
Ghaffarnejad, H.; Yaraie, E.
2017-04-01
Using scalar-vector-tensor Brans Dicke (VBD) gravity (Ghaffarnejad in Gen Relativ Gravit 40:2229, 2008; Gen Relativ Gravit 41:2941, 2009) in presence of self interaction BD potential V(φ ) and perfect fluid matter field action we solve corresponding field equations via dynamical system approach for flat Friedmann Robertson Walker metric (FRW). We obtained three type critical points for Λ CDM vacuum de Sitter era where stability of our solutions are depended to choose particular values of BD parameter ω . One of these fixed points is supported by a constant potential which is stable for ω equations for de Sitter, dust and radiation eras. We should point also potentials which support dust and radiation eras must be similar to V(φ )˜ φ ^{-1/2} and V(φ )˜ φ ^{-1} respectively. In short our study predicts that radiation and dust eras of our VBD-FRW cosmology transmit to stable de Sitter state via non-constant potential (effective variable cosmological parameter) by choosing ω =0.27647.
Investigations on Actuator Dynamics through Theoretical and Finite Element Approach
Directory of Open Access Journals (Sweden)
Somashekhar S. Hiremath
2010-01-01
Full Text Available This paper gives a new approach for modeling the fluid-structure interaction of servovalve component-actuator. The analyzed valve is a precision flow control valve-jet pipe electrohydraulic servovalve. The positioning of an actuator depends upon the flow rate from control ports, in turn depends on the spool position. Theoretical investigation is made for No-load condition and Load condition for an actuator. These are used in finite element modeling of an actuator. The fluid-structure-interaction (FSI is established between the piston and the fluid cavities at the piston end. The fluid cavities were modeled with special purpose hydrostatic fluid elements while the piston is modeled with brick elements. The finite element method is used to simulate the variation of cavity pressure, cavity volume, mass flow rate, and the actuator velocity. The finite element analysis is extended to study the system's linearized response to harmonic excitation using direct solution steady-state dynamics. It was observed from the analysis that the natural frequency of the actuator depends upon the position of the piston in the cylinder. This is a close match with theoretical and simulation results. The effect of bulk modulus is also presented in the paper.
A DYNAMICAL SYSTEM APPROACH IN MODELING TECHNOLOGY TRANSFER
Directory of Open Access Journals (Sweden)
Hennie Husniah
2016-05-01
Full Text Available In this paper we discuss a mathematical model of two parties technology transfer from a leader to a follower. The model is reconstructed via dynamical system approach from a known standard Raz and Assa model and we found some important conclusion which have not been discussed in the original model. The model assumes that in the absence of technology transfer from a leader to a follower, both the leader and the follower have a capability to grow independently with a known upper limit of the development. We obtain a rich mathematical structure of the steady state solution of the model. We discuss a special situation in which the upper limit of the technological development of the follower is higher than that of the leader, but the leader has started earlier than the follower in implementing the technology. In this case we show a paradox stating that the follower is unable to reach its original upper limit of the technological development could appear whenever the transfer rate is sufficiently high. We propose a new model to increase realism so that any technological transfer rate could only has a positive effect in accelerating the rate of growth of the follower in reaching its original upper limit of the development.
Remotely Sensed Monitoring of Small Reservoir Dynamics: A Bayesian Approach
Directory of Open Access Journals (Sweden)
Dirk Eilander
2014-01-01
Full Text Available Multipurpose small reservoirs are important for livelihoods in rural semi-arid regions. To manage and plan these reservoirs and to assess their hydrological impact at a river basin scale, it is important to monitor their water storage dynamics. This paper introduces a Bayesian approach for monitoring small reservoirs with radar satellite images. The newly developed growing Bayesian classifier has a high degree of automation, can readily be extended with auxiliary information and reduces the confusion error to the land-water boundary pixels. A case study has been performed in the Upper East Region of Ghana, based on Radarsat-2 data from November 2012 until April 2013. Results show that the growing Bayesian classifier can deal with the spatial and temporal variability in synthetic aperture radar (SAR backscatter intensities from small reservoirs. Due to its ability to incorporate auxiliary information, the algorithm is able to delineate open water from SAR imagery with a low land-water contrast in the case of wind-induced Bragg scattering or limited vegetation on the land surrounding a small reservoir.
A Dynamic Systems Theory approach to second language acquisition
de Bot, K.; Lowie, W.M.; Verspoor, M.H.
In this article it is argued that language can be seen as a dynamic system, i.e. a set of variables that interact over time, and that language development can be seen as a dynamic process. Language development shows some of the core characteristics of dynamic systems: sensitive dependence on initial
A Dynamic Systems Theory approach to second language acquisition
de Bot, K.; Lowie, W.M.; Verspoor, M.H.
2007-01-01
In this article it is argued that language can be seen as a dynamic system, i.e. a set of variables that interact over time, and that language development can be seen as a dynamic process. Language development shows some of the core characteristics of dynamic systems: sensitive dependence on initial
Schmid, Verena
2012-06-16
Emergency service providers are supposed to locate ambulances such that in case of emergency patients can be reached in a time-efficient manner. Two fundamental decisions and choices need to be made real-time. First of all immediately after a request emerges an appropriate vehicle needs to be dispatched and send to the requests' site. After having served a request the vehicle needs to be relocated to its next waiting location. We are going to propose a model and solve the underlying optimization problem using approximate dynamic programming (ADP), an emerging and powerful tool for solving stochastic and dynamic problems typically arising in the field of operations research. Empirical tests based on real data from the city of Vienna indicate that by deviating from the classical dispatching rules the average response time can be decreased from 4.60 to 4.01 minutes, which corresponds to an improvement of 12.89%. Furthermore we are going to show that it is essential to consider time-dependent information such as travel times and changes with respect to the request volume explicitly. Ignoring the current time and its consequences thereafter during the stage of modeling and optimization leads to suboptimal decisions.
A user's guide to the Flexible Spacecraft Dynamics and Control Program
Fedor, J. V.
1984-01-01
A guide to the use of the Flexible Spacecraft Dynamics Program (FSD) is presented covering input requirements, control words, orbit generation, spacecraft description and simulation options, and output definition. The program can be used in dynamics and control analysis as well as in orbit support of deployment and control of spacecraft. The program is applicable to inertially oriented spinning, Earth oriented or gravity gradient stabilized spacecraft. Internal and external environmental effects can be simulated.
A dynamic programming model for optimal planning of aquifer storage and recovery facility operations
Uddameri, V.
2007-01-01
Aquifer storage recovery (ASR) is an innovative technology with the potential to augment dwindling water resources in regions experiencing rapid growth and development. Planning and design of ASR systems requires quantifying how much water should be stored and appropriate times for storage and withdrawals within a planning period. A monthly scale planning model has been developed in this study to derive optimal (least cost) long-term policies for operating ASR systems and is solved using a recursive deterministic dynamic programming approach. The outputs of the model include annual costs of operation, the amount of water to be imported each month as well as the schedule for storage and extraction. A case study modeled after a proposed ASR system for Mustang Island and Padre Island service areas of the city of Corpus Christi is used to illustrate the utility of the developed model. The results indicate that for the assumed baseline demands, the ASR system is to be kept operational for a period of 4 months starting from May through August. Model sensitivity analysis indicated that increased seasonal shortages can be met using ASR with little additional costs. For the assumed cost structure, a 16% shortage increased the costs by 1.6%. However, the operation time of ASR increased from 4 to 8 months. The developed dynamic programming model is a useful tool to assess the feasibility of evaluating the use of ASR systems during regional-scale water resources planning endeavors.
Detecting Wash Trade in Financial Market Using Digraphs and Dynamic Programming.
Cao, Yi; Li, Yuhua; Coleman, Sonya; Belatreche, Ammar; McGinnity, Thomas Martin
2016-11-01
A wash trade refers to the illegal activities of traders who utilize carefully designed limit orders to manually increase the trading volumes for creating a false impression of an active market. As one of the primary formats of market abuse, a wash trade can be extremely damaging to the proper functioning and integrity of capital markets. The existing work focuses on collusive clique detections based on certain assumptions of trading behaviors. Effective approaches for analyzing and detecting wash trade in a real-life market have yet to be developed. This paper analyzes and conceptualizes the basic structures of the trading collusion in a wash trade by using a directed graph of traders. A novel method is then proposed to detect the potential wash trade activities involved in a financial instrument by first recognizing the suspiciously matched orders and then further identifying the collusions among the traders who submit such orders. Both steps are formulated as a simplified form of the knapsack problem, which can be solved by dynamic programming approaches. The proposed approach is evaluated on seven stock data sets from the NASDAQ and the London Stock Exchange. The experimental results show that the proposed approach can effectively detect all primary wash trade scenarios across the selected data sets.
Energy Technology Data Exchange (ETDEWEB)
Tinianow, M.A.; Rotelli, R.L. Jr.; Baird, J.A.
1984-06-01
User instructions for the GEODYN Interactive Finite Element Computer Program are presented. The program is capable of performing the analysis of the three-dimensional transient dynamic response of a Polycrystalline Diamond Compact Bit - Bit Sub arising from the intermittent contact of the bit with the downhole rock formations. The program accommodates non-linear, time dependent, loading and boundary conditions.
Genetic programming approach to evaluate complexity of texture images
Ciocca, Gianluigi; Corchs, Silvia; Gasparini, Francesca
2016-11-01
We adopt genetic programming (GP) to define a measure that can predict complexity perception of texture images. We perform psychophysical experiments on three different datasets to collect data on the perceived complexity. The subjective data are used for training, validation, and test of the proposed measure. These data are also used to evaluate several possible candidate measures of texture complexity related to both low level and high level image features. We select four of them (namely roughness, number of regions, chroma variance, and memorability) to be combined in a GP framework. This approach allows a nonlinear combination of the measures and could give hints on how the related image features interact in complexity perception. The proposed complexity measure M exhibits Pearson correlation coefficients of 0.890 on the training set, 0.728 on the validation set, and 0.724 on the test set. M outperforms each of all the single measures considered. From the statistical analysis of different GP candidate solutions, we found that the roughness measure evaluated on the gray level image is the most dominant one, followed by the memorability, the number of regions, and finally the chroma variance.
Improving the Held and Karp Approach with Constraint Programming
Benchimol, Pascal; Régin, Jean-Charles; Rousseau, Louis-Martin; Rueher, Michel; van Hoeve, Willem-Jan
Held and Karp have proposed, in the early 1970s, a relaxation for the Traveling Salesman Problem (TSP) as well as a branch-and-bound procedure that can solve small to modest-size instances to optimality [4, 5]. It has been shown that the Held-Karp relaxation produces very tight bounds in practice, and this relaxation is therefore applied in TSP solvers such as Concorde [1]. In this short paper we show that the Held-Karp approach can benefit from well-known techniques in Constraint Programming (CP) such as domain filtering and constraint propagation. Namely, we show that filtering algorithms developed for the weighted spanning tree constraint [3, 8] can be adapted to the context of the Held and Karp procedure. In addition to the adaptation of existing algorithms, we introduce a special-purpose filtering algorithm based on the underlying mechanisms used in Prim's algorithm [7]. Finally, we explored two different branching schemes to close the integrality gap. Our initial experimental results indicate that the addition of the CP techniques to the Held-Karp method can be very effective.
Lazy evaluation of FP programs: A data-flow approach
Energy Technology Data Exchange (ETDEWEB)
Wei, Y.H. [International Business Machines Corp., Yorktown Heights, NY (United States). Thomas J. Watson Research Center; Gaudiot, J.L. [University of Southern California, Los Angeles, CA (United States). Computer Research Inst.
1988-12-31
This paper presents a lazy evaluation system for the list-based functional language, Backus` FP in data-driven environment. A superset language of FP, called DFP (Demand-driven FP), is introduced. FP eager programs are transformed into DFP lazy programs which contain the notions of demands. The data-driven execution of DFP programs has the same effects of lazy evaluation. DFP lazy programs have the property of always evaluating a sufficient and necessary result. The infinite sequence generator is used to demonstrate the eager-lazy program transformation and the execution of the lazy programs.
Luo, Biao; Wu, Huai-Ning; Li, Han-Xiong
2015-04-01
Highly dissipative nonlinear partial differential equations (PDEs) are widely employed to describe the system dynamics of industrial spatially distributed processes (SDPs). In this paper, we consider the optimal control problem of the general highly dissipative SDPs, and propose an adaptive optimal control approach based on neuro-dynamic programming (NDP). Initially, Karhunen-Loève decomposition is employed to compute empirical eigenfunctions (EEFs) of the SDP based on the method of snapshots. These EEFs together with singular perturbation technique are then used to obtain a finite-dimensional slow subsystem of ordinary differential equations that accurately describes the dominant dynamics of the PDE system. Subsequently, the optimal control problem is reformulated on the basis of the slow subsystem, which is further converted to solve a Hamilton-Jacobi-Bellman (HJB) equation. HJB equation is a nonlinear PDE that has proven to be impossible to solve analytically. Thus, an adaptive optimal control method is developed via NDP that solves the HJB equation online using neural network (NN) for approximating the value function; and an online NN weight tuning law is proposed without requiring an initial stabilizing control policy. Moreover, by involving the NN estimation error, we prove that the original closed-loop PDE system with the adaptive optimal control policy is semiglobally uniformly ultimately bounded. Finally, the developed method is tested on a nonlinear diffusion-convection-reaction process and applied to a temperature cooling fin of high-speed aerospace vehicle, and the achieved results show its effectiveness.
Zhu, Yuanheng; Zhao, Dongbin; Li, Xiangjun
2017-03-01
H∞ control is a powerful method to solve the disturbance attenuation problems that occur in some control systems. The design of such controllers relies on solving the zero-sum game (ZSG). But in practical applications, the exact dynamics is mostly unknown. Identification of dynamics also produces errors that are detrimental to the control performance. To overcome this problem, an iterative adaptive dynamic programming algorithm is proposed in this paper to solve the continuous-time, unknown nonlinear ZSG with only online data. A model-free approach to the Hamilton-Jacobi-Isaacs equation is developed based on the policy iteration method. Control and disturbance policies and value are approximated by neural networks (NNs) under the critic-actor-disturber structure. The NN weights are solved by the least-squares method. According to the theoretical analysis, our algorithm is equivalent to a Gauss-Newton method solving an optimization problem, and it converges uniformly to the optimal solution. The online data can also be used repeatedly, which is highly efficient. Simulation results demonstrate its feasibility to solve the unknown nonlinear ZSG. When compared with other algorithms, it saves a significant amount of online measurement time.
Dynamical approach to displacement jumps in nanoindentation experiments
K, Srikanth; Ananthakrishna, G.
2017-01-01
The load-controlled mode is routinely used in nanoindentation experiments. Yet there are no simulations or models that predict the generic features of force-displacement F -z curves, in particular, the existence of several displacement jumps of decreasing magnitude. Here, we show that the recently developed dislocation dynamical model predicts all the generic features when the model is appropriately coupled to an equation defining the load rate. Since jumps in the indentation depth result from the plastic deformation occurring inside the sample, we devise a method for calculating this contribution by setting up a system of coupled nonlinear time evolution equations for the mobile and forest dislocation densities. The equations are then coupled to the force rate equation. We include nucleation, multiplication, and propagation threshold mechanisms for the mobile dislocations apart from other well known dislocation transformation mechanisms between the mobile and forest dislocations. The commonly used Berkovitch indenter is considered. The ability of the approach is illustrated by adopting experimental parameters such as the indentation rate, the geometrical quantities defining the Berkovitch indenter including the nominal tip radius, and other parameters. We identify specific dislocation mechanisms contributing to different regions of the F -z curve as a first step for obtaining a good fit to a given experimental F -z curve. This is done by studying the influence of the parameters on the model F -z curves. In addition, the study demonstrates that the model predicts all the generic features of nanoindentation such as the existence of an initial elastic branch followed by several displacement jumps of decreasing magnitude, and residual plasticity after unloading for a range of model parameter values. Further, an optimized set of parameter values can be easily determined that gives a good fit to the experimental force-displacement curve for Al single crystals of (110
Novel Approaches to Cellular Transplantation from the US Space Program
Pellis, Neal R.; Homick, Jerry L. (Technical Monitor)
1999-01-01
Research in the treatment of type I diabetes is entering a new era that takes advantage of our knowledge in an ever increasing variety of scientific disciplines. Some may originate from very diverse sources, one of which is the Space Program at National Aeronautics and Space Administration (NASA). The Space Program contributes to diabetes-related research in several treatment modalities. As an ongoing effort for medical monitoring of personnel involved in space exploration activities NASA and the extramural scientific community investigate strategies for noninvasive estimation of blood glucose levels. Part of the effort in the space protein crystal growth program is high-resolution structural analysis insulin as a means to better understand the interaction with its receptor and with host immune components and as a basis for rational design of a "better" insulin molecule. The Space Program is also developing laser technology for potential early cataract detection as well as a noninvasive analyses for addressing preclinical diabetic retinopathy. Finally, NASA developed an exciting cell culture system that affords some unique advantages in the propagation and maintenance of mammalian cells in vitro. The cell culture system was originally designed to maintain cell suspensions with a minimum of hydrodynamic and mechanical sheer while awaiting launch into microgravity. Currently the commercially available NASA bioreactor (Synthecon, Inc., Houston, TX) is used as a research tool in basic and applied cell biology. In recent years there is continued strong interest in cellular transplantation as treatment for type I diabetes. The advantages are the potential for successful long-term amelioration and a minimum risk for morbidity in the event of rejection of the transplanted cells. The pathway to successful application of this strategy is accompanied by several substantial hurdles: (1) isolation and propagation of a suitable uniform donor cell population; (2) management of
Robust Generation of Dynamic Data Structure Visualizations with Multiple Interaction Approaches
Cross, James H., II; Hendrix, T. Dean; Umphress, David A.; Barowski, Larry A.; Jain, Jhilmil; Montgomery, Lacey N.
2009-01-01
jGRASP has three integrated approaches for interacting with its dynamic viewers for data structures: debugger, workbench, and text-based interactions that allow individual Java statements and expressions to be executed/evaluated. These approaches can be used together to provide a complementary set of interactions with the dynamic viewers. Data…
A demographic approach to firm dynamics: formation of new firms and survival of old ones
Nijkamp, P.; Geenhuizen, van M.
1995-01-01
This paper introduces a new approach to firm dynamics, named demography of firms. It is the study of demographic events in a population of firms. Thepaper argues that withina demographic approach, attention should be paid to a broad range of firm dynamics, including both new firm formation and survi
Dynamic assessment: an approach to assessing children's language-learning potential.
Gutiérrez-Clellen, V F
2000-01-01
Dynamic assessment represents an alternative approach to traditional language assessments. In dynamic assessment, the examiner attempts to assess the child's potential for language change or modifiability. This article discusses the development of this approach from its early psychological applications to current models of dynamic assessment as they apply to the assessment of child language. Dynamic assessment is particularly useful in addressing cultural differences that may influence children's assessment performance. The approach involves a test-teach-retest paradigm that includes mediated learning experiences, measures of test score gains, ratings of modifiability and language-learning strategies, as well as analyses of qualitative changes in children's responses.
A Fuzzy Linear Programming Approach for Aggregate Production Planning
DEFF Research Database (Denmark)
Iris, Cagatay; Cevikcan, Emre
2014-01-01
a mathematical programming framework for aggregate production planning problem under imprecise data environment. After providing background information about APP problem, together with fuzzy linear programming, the fuzzy linear programming model of APP is solved on an illustrative example for different a...
An Approach to Theory-Based Youth Programming
Duerden, Mat D.; Gillard, Ann
2011-01-01
A key but often overlooked aspect of intentional, out-of-school-time programming is the integration of a guiding theoretical framework. The incorporation of theory in programming can provide practitioners valuable insights into essential processes and principles of successful programs. While numerous theories exist that relate to youth development…
An Approach to Theory-Based Youth Programming
Duerden, Mat D.; Gillard, Ann
2011-01-01
A key but often overlooked aspect of intentional, out-of-school-time programming is the integration of a guiding theoretical framework. The incorporation of theory in programming can provide practitioners valuable insights into essential processes and principles of successful programs. While numerous theories exist that relate to youth development…
Employee Assistance Programs: A New Human Resource Approach.
Gould, Gary M.; Schneider, John H.
1983-01-01
After reviewing industrial sector program results, University of Southern California administration officials agreed to finance a counseling and consulting program for USC employees. The program serves as an adjunct to the personnel office in areas such as outplacement, sexual harassment, and conflict resolution. (MLW)
Towards HPC++: A Unified Approach to Parallel Programming in C++
1998-10-30
Compositional C++ or CC++, is a general purpose parallel programming language designed to support a wide range of parallel programming styles. By...appropriate for parallelizing the range of applications that one would write in C++. CC++ supports the integration of different parallel programming styles
Employee Assistance Programs: A New Human Resource Approach.
Gould, Gary M.; Schneider, John H.
1983-01-01
After reviewing industrial sector program results, University of Southern California administration officials agreed to finance a counseling and consulting program for USC employees. The program serves as an adjunct to the personnel office in areas such as outplacement, sexual harassment, and conflict resolution. (MLW)
Efficient and exact maximum likelihood quantisation of genomic features using dynamic programming.
Song, Mingzhou; Haralick, Robert M; Boissinot, Stéphane
2010-01-01
An efficient and exact dynamic programming algorithm is introduced to quantise a continuous random variable into a discrete random variable that maximises the likelihood of the quantised probability distribution for the original continuous random variable. Quantisation is often useful before statistical analysis and modelling of large discrete network models from observations of multiple continuous random variables. The quantisation algorithm is applied to genomic features including the recombination rate distribution across the chromosomes and the non-coding transposable element LINE-1 in the human genome. The association pattern is studied between the recombination rate, obtained by quantisation at genomic locations around LINE-1 elements, and the length groups of LINE-1 elements, also obtained by quantisation on LINE-1 length. The exact and density-preserving quantisation approach provides an alternative superior to the inexact and distance-based univariate iterative k-means clustering algorithm for discretisation.
Detection and Extraction of Roads from High Resolution Satellites Images with Dynamic Programming
Benzouai, Siham; Smara, Youcef
2010-12-01
The advent of satellite images allows now a regular and a fast digitizing and update of geographic data, especially roads which are very useful for Geographic Information Systems (GIS) applications such as transportation, urban pollution, geomarketing, etc. For this, several studies have been conducted to automate roads extraction in order to minimize the manual processes [4]. In this work, we are interested in roads extraction from satellite imagery with high spatial resolution (at best equal to 10 m). The method is semi automatic and follows a linear approach where road is considered as a linear object. As roads extraction is a pattern recognition problem, it is useful, above all, to characterize roads. After, we realize a pre-processing by applying an Infinite Size Edge Filter -ISEF- and processing method based on dynamic programming concept, in particular, Fishler algorithm designed by F*.
Dynamic programming for infinite horizon boundary control problems of PDE's with age structure
Faggian, Silvia
2008-01-01
We develop the dynamic programming approach for a family of infinite horizon boundary control problems with linear state equation and convex cost. We prove that the value function of the problem is the unique regular solution of the associated stationary Hamilton--Jacobi--Bellman equation and use this to prove existence and uniqueness of feedback controls. The idea of studying this kind of problem comes from economic applications, in particular from models of optimal investment with vintage capital. Such family of problems has already been studied in the finite horizon case by Faggian. The infinite horizon case is more difficult to treat and it is more interesting from the point of view of economic applications, where what mainly matters is the behavior of optimal trajectories and controls in the long run. The study of infinite horizon is here performed through a nontrivial limiting procedure from the corresponding finite horizon problem.
Molecular Approaches to Understanding C & N Dynamics in MArine Sediments
Energy Technology Data Exchange (ETDEWEB)
Arturo Massol; James Tiedje; Jizhong Zhou; Allan Devol
2007-05-16
Continental margin sediments constitute only about 10% of the total sediment surface area in the world’s oceans, nevertheless they are the dominant sites of nitrogen (N) cycling. Recent studies suggest that the oceanic nitrogen budget is unbalanced, primarily due to a higher nitrogen removal rate in contrast to the fixation rate, and it has been suggested that denitrification activity contributes significantly to this imbalance. Although denitrification in marine environments has been studied intensively at the process level, little is known about the species abundance, composition, distribution, and functional differences of the denitrifying population. Understanding the diversity of microbial populations in marine environments, their responses to various environmental factors such as NO3-, and how this impact the rate of denitrification is critical to predict global N dynamics. Environmental Microbiology has the prompt to study the influence of each microbial population on a biogeochemical process within a given ecosystem. Culture-dependent and –independent techniques using nucleic acid probes can access the identity and activity of cultured and uncultured microorganisms. Nucleic acid probes can target distintict genes which set phylogenetic relationships, such as rDNA 16S, DNA gyrase (gyrB) and RNA polymerase sigma 70 factor (rpoD). In the other hand, the genetic capabilities and their expression could be tracked using probes that target several functional genes, such as nirS, nirK, nosZ, and nifH, which are genes involved in denitrification. Selective detection of cells actively expressing functional genes within a community using In Situ Reverse Transcription-PCR (ISRT-PCR) could become a powerful culture-independent technique in microbial ecology. Here we describe an approach to study the expression of nirS genes in denitrifying bacteria. Pure cultures of Pseudomonas stutzeri and Paracoccus denitrificans, as well as co-cultures with non
A dynamic appearance descriptor approach to facial actions temporal modeling
Jiang, Bihan; Valstar, Michel; Martinez, Brais; Pantic, Maja
2014-01-01
Both the configuration and the dynamics of facial expressions are crucial for the interpretation of human facial behavior. Yet to date, the vast majority of reported efforts in the field either do not take the dynamics of facial expressions into account, or focus only on prototypic facial expression
The dynamics of a usage-based approach
Verspoor, Marjolijn; Daems, Jocelyn; Zenner, Eline; Heylen, Kris; Speelman, Dirk; Cuyckens, Hubert
2015-01-01
This contribution seeks to connect usage based linguistics with dynamic systems theory, in particular as applied by Edelman (1989) and Thelen and Smith (1994). Edelman’s dynamic biological system starts off with a few simple sub-systems (perception, action, value), all of which interacting with each
A New Approach to Commercialization of NASA's Human Research Program Technologies Project
National Aeronautics and Space Administration — This Phase I SBIR proposal describes, "A New Approach to Commercialization of NASA's Human Research Program Technologies." NASA has a powerful research...
Energy Technology Data Exchange (ETDEWEB)
Collins, J.D.; Hudson, J.M.; Chrostowski, J.D.
1979-02-01
A computational methodology is presented for the prediction of core melt probabilities in a nuclear power plant due to earthquake events. The proposed model has four modules: seismic hazard, structural dynamic (including soil-structure interaction), component failure and core melt sequence. The proposed modules would operate in series and would not have to be operated at the same time. The basic statistical approach uses a Monte Carlo simulation to treat random and systematic error but alternate statistical approaches are permitted by the program design.
A Fractal Approach to Dynamic Inference and Distribution Analysis
Directory of Open Access Journals (Sweden)
Marieke M.J.W. van Rooij
2013-01-01
Full Text Available Event-distributions inform scientists about the variability and dispersion of repeated measurements. This dispersion can be understood from a complex systems perspective, and quantified in terms of fractal geometry. The key premise is that a distribution’s shape reveals information about the governing dynamics of the system that gave rise to the distribution. Two categories of characteristic dynamics are distinguished: additive systems governed by component-dominant dynamics and multiplicative or interdependent systems governed by interaction-dominant dynamics. A logic by which systems governed by interaction-dominant dynamics are expected to yield mixtures of lognormal and inverse power-law samples is discussed. These mixtures are described by a so-called cocktail model of response times derived from human cognitive performances. The overarching goals of this article are twofold: First, to offer readers an introduction to this theoretical perspective and second, to offer an overview of the related statistical methods.
Dynamics and Control of Humanoid Robots: A Geometrical Approach
Ivancevic, Vladimir G
2011-01-01
his paper reviews modern geometrical dynamics and control of humanoid robots. This general Lagrangian and Hamiltonian formalism starts with a proper definition of humanoid's configuration manifold, which is a set of all robot's active joint angles. Based on the `covariant force law', the general humanoid's dynamics and control are developed. Autonomous Lagrangian dynamics is formulated on the associated `humanoid velocity phase space', while autonomous Hamiltonian dynamics is formulated on the associated `humanoid momentum phase space'. Neural-like hierarchical humanoid control naturally follows this geometrical prescription. This purely rotational and autonomous dynamics and control is then generalized into the framework of modern non-autonomous biomechanics, defining the Hamiltonian fitness function. The paper concludes with several simulation examples. Keywords: Humanoid robots, Lagrangian and Hamiltonian formalisms, neural-like humanoid control, time-dependent biodynamics
Kassa, Semu Mitiku; Tsegay, Teklay Hailay
2017-08-01
Tri-level optimization problems are optimization problems with three nested hierarchical structures, where in most cases conflicting objectives are set at each level of hierarchy. Such problems are common in management, engineering designs and in decision making situations in general, and are known to be strongly NP-hard. Existing solution methods lack universality in solving these types of problems. In this paper, we investigate a tri-level programming problem with quadratic fractional objective functions at each of the three levels. A solution algorithm has been proposed by applying fuzzy goal programming approach and by reformulating the fractional constraints to equivalent but non-fractional non-linear constraints. Based on the transformed formulation, an iterative procedure is developed that can yield a satisfactory solution to the tri-level problem. The numerical results on various illustrative examples demonstrated that the proposed algorithm is very much promising and it can also be used to solve larger-sized as well as n-level problems of similar structure.
Sabar, Nasser R; Ayob, Masri; Kendall, Graham; Qu, Rong
2015-02-01
Hyper-heuristics are search methodologies that aim to provide high-quality solutions across a wide variety of problem domains, rather than developing tailor-made methodologies for each problem instance/domain. A traditional hyper-heuristic framework has two levels, namely, the high level strategy (heuristic selection mechanism and the acceptance criterion) and low level heuristics (a set of problem specific heuristics). Due to the different landscape structures of different problem instances, the high level strategy plays an important role in the design of a hyper-heuristic framework. In this paper, we propose a new high level strategy for a hyper-heuristic framework. The proposed high-level strategy utilizes a dynamic multiarmed bandit-extreme value-based reward as an online heuristic selection mechanism to select the appropriate heuristic to be applied at each iteration. In addition, we propose a gene expression programming framework to automatically generate the acceptance criterion for each problem instance, instead of using human-designed criteria. Two well-known, and very different, combinatorial optimization problems, one static (exam timetabling) and one dynamic (dynamic vehicle routing) are used to demonstrate the generality of the proposed framework. Compared with state-of-the-art hyper-heuristics and other bespoke methods, empirical results demonstrate that the proposed framework is able to generalize well across both domains. We obtain competitive, if not better results, when compared to the best known results obtained from other methods that have been presented in the scientific literature. We also compare our approach against the recently released hyper-heuristic competition test suite. We again demonstrate the generality of our approach when we compare against other methods that have utilized the same six benchmark datasets from this test suite.
APPROACH TO IMPROVEMENT OF ROBOT TRAJECTORY ACCURACY BY DYNAMIC COMPENSATION
Institute of Scientific and Technical Information of China (English)
Wang Gang; Ren Guoli; Yan Xiang'an; Wang Guodong
2004-01-01
Some dynamic factors, such as inertial forces and friction, may affect the robot trajectory accuracy. But these effects are not taken into account in robot motion control schemes. Dynamic control methods, on the other hand, require the dynamic model of robot and the implementation of new type controller. A method to improve robot trajectory accuracy by dynamic compensation in robot motion control system is proposed. The dynamic compensation is applied as an additional velocity feedforward and a multilayer neural network is employed to realize the robot inverse dynamics. The complicated dynamic parameter identification problem becomes a learning process of neural network connecting weights under supervision. The finite Fourier series is used to activate each actuator of robot joints for obtaining training samples. Robot control system, consisting of an industrial computer and a digital motion controller, is implemented. The system is of open architecture with velocity feedforward function. The proposed method is not model-based and combines the advantages of close-loop position control and computed torque control. Experimental results have shown that the method is validatities to improve the robot trajectory accuracy.
The Portfolio Approach Developed to Underpin the Capital Investment Program Plan Review (CIPPR)
2014-11-06
Basinger, Director, DCI, CFD Scientific Letter The PORTFOLIO APPROACH developed to underpin the Capital Investment Program Plan Review (CIPPR) To better...the key concepts about the new analytical approach that has been used to produce alternative project portfolios for consideration within the Capital...Investment Program Plan Review (CIPPR). This approach has come to be known as the portfolio approach. This letter begins with a brief description of
Productivity and Regional Employment in Spain: A Dynamic Approach
Directory of Open Access Journals (Sweden)
F. Javier Escribá Pérez
2013-01-01
Full Text Available This paper analyses the impact of sectorial and territorial factors on the dynamics of employment in regional industries in Spain over the period 1980-2006. A dynamic panel data model is estimated using panel data techniques (System-GMM, which provide an alternative methodology for addressing the problem of variable endogeneity. The results confirm the robustness of the contemporary effects: diversification, market size and dynamics in the sector affect employment in the short term. However, effects in the long term are more uncertain.
Bellman's GAP : a 2nd generation language and system for algebraic dynamic programming
Sauthoff, Georg
2010-01-01
The dissertation describes the new Bellmans GAP which is a programming system for writing dynamic programming algorithms over sequential data. It is the second generation implementation of the algebraic dynamic programming framework (ADP). The system includes the multi-paradigm language (GAP-L), its compiler (GAP-C), functional modules (GAP-M) and a web site (GAP Pages) to experiment with GAP-L programs. GAP-L includes declarative constructs, e.g. tree grammars to model the search space, and...
Cui, Yunduan; Matsubara, Takamitsu; Sugimoto, Kenji
2017-06-29
We propose a new value function approach for model-free reinforcement learning in Markov decision processes involving high dimensional states that addresses the issues of brittleness and intractable computational complexity, therefore rendering the value function approach based reinforcement learning algorithms applicable to high dimensional systems. Our new algorithm, Kernel Dynamic Policy Programming (KDPP) smoothly updates the value function in accordance to the Kullback-Leibler divergence between current and updated policies. Stabilizing the learning in this manner enables the application of the kernel trick to value function approximation, which greatly reduces computational requirements for learning in high dimensional state spaces. The performance of KDPP against other kernel trick based value function approaches is first investigated in a simulated n DOF manipulator reaching task, where only KDPP efficiently learned a viable policy at n=40. As an application to a real world high dimensional robot system, KDPP successfully learned the task of unscrewing a bottle cap via a Pneumatic Artificial Muscle (PAM) driven robotic hand with tactile sensors; a system with a state space of 32 dimensions, while given limited samples and with ordinary computing resources. Copyright © 2017 Elsevier Ltd. All rights reserved.
The Configuration Of Supply Chain Agritourism To Improve The Performance With Dynamic Programming
Directory of Open Access Journals (Sweden)
Sahnaz Ubud
2015-09-01
Full Text Available The purposes of this research is to implementation about the configuration of Supply Chain Agritourism in Mekarsari Tours Garden and result a decision making which must be done by top level management about their supply chain configuration. Because now Mekarsari, the biggest fruit garden in the world, have a lot of type of fruit which must be supply for the customer depend on the season with on time. So Mekarsari must know about their configuration from supplier to customer to improve their performance. The Respondents for this research is selected based on the results of supply chain maping from the worker in the garden, the top level management until the end customer. Supply chian network is formed consisting of farm workers to the end customers, especially those located in the tourist are of green land zone. The type of data is displayed in a supply chain modeling approach is to use the dynamic system. It’s consists of numeric data, the written data and mental models. That data is collected and processed into a design model. The design model is using system dynamics methodology. In compiling the system dynamics model has been used software Vensim Professional Academic Ventana 5.7. The result of this research is a configuration of Supply Chain Agritourism which is developed from the supplier until the end customer in Mekarsari tours Garden. From the Dynamic Programming, the result is a decision making which must be done by the top level management to improve the supply chain performance, especially in the green land zone.
FINANCIAL STRUCTURE OPTIMIZATION BY USING A GOAL PROGRAMMING APPROACH
Directory of Open Access Journals (Sweden)
Tunjo Perić
2012-12-01
Full Text Available This paper proposes a new methodology for solving the multiple objective fractional linear programming problems using Taylor’s formula and goal programming techniques. The proposed methodology is tested on the example of company's financial structure optimization. The obtained results indicate the possibility of efficient application of the proposed methodology for company's financial structure optimization as well as for solving other multi-criteria fractional programming problems.
Statistical physics approaches to subnetwork dynamics in biochemical systems
Bravi, Barbara
2016-01-01
We apply a Gaussian variational approximation to model reduction in large biochemical networks of unary and binary reactions. We focus on a small subset of variables (subnetwork) of interest, e.g. because they are accessible experimentally, embedded in a larger network (bulk). The key goal is to write dynamical equations reduced to the subnetwork but still retaining the effects of the bulk. As a result, the subnetwork-reduced dynamics contains a memory term and an extrinsic noise term with non-trivial temporal correlations. We first derive expressions for this memory and noise in the linearized (Gaussian) dynamics and then use a perturbative power expansion to obtain first order nonlinear corrections. For the case of vanishing intrinsic noise, our description is explicitly shown to be equivalent to projection methods up to quadratic terms, but it is applicable also in the presence of stochastic fluctuations in the original dynamics. An example from the Epidermal Growth Factor Receptor (EGFR) signalling pathwa...
Relative weights approach to dynamical fermions at finite densities
Greensite, Jeff
2016-01-01
The method of relative weights, coupled with mean field theory, is applied to the problem of simulating gauge theories with dynamical staggered fermions at finite densities. We present initial results and discuss issues so far encountered.
South African energy model: a system dynamics approach
CSIR Research Space (South Africa)
Musango, JK
2009-07-01
Full Text Available & Andrea Bassi2 1 Council for Scientific and Industrial Research (CSIR), South Africa 2Millenium Institute, Arlington (VA) International Conference of System Dynamics Society Albuquerque, New Mexico July 26 - 31, 2009 South African energy model: a...
New Highly Dynamic Approach for Thrust Vector Control
Hecht, M.; Ettl, J.; Grothe, D.; Hrbud, I.
2015-09-01
For a new launcher system a thrust vector control system is needed. This launch vehicle system consists of two rockets which are namely the VS-50 (two-stage suborbital vehicle) and the VLM-1 (three-stage microsatellite launch vehicle). VLM-1 and VS-50 are developed in a cooperation between the German Aerospace Center (DLR) and the Brazilian Aeronautics and Space Institute (IAE). To keep these two rockets on its trajectory during flight a highly dynamic thrust vector control system is required. For the purpose of developing such a highly dynamic thrust vector control system a master thesis was written by the author. The development includes all mechanical constructions as well as control algorithms and electronics design. Moreover an optimization of control algorithms was made to increase the dynamic capabilities of the thrust vector control system. The composition of the right components plus the sophisticated control algorithm make the thrust vector control system highly dynamic.
A Dynamic Approach for Anomaly Detection in AODV
Directory of Open Access Journals (Sweden)
P.Vigneshwaran
2011-02-01
Full Text Available Mobile ad hoc networks (MANETs are relatively vuln erable to malicious network attacks, and therefore, security is a more significant issue than infrastru cture-based wire-less networks. In MANETs, it is di fficult to identify malicious hosts as the topology of the network dynamically changes. A malicious host can e asily interrupt a route for which it is one of the formin g nodes in the communication path. Since the topolo gy of a MANET dynamically changes, the mere use of a stat ic baseline profile is not efficient. We proposed a new anomaly-detection scheme based on a dynamic learnin g process that allows the training data to be updat ed at particular time intervals. Our dynamic learning process involves calculating the projection distanc es based on multidimensional statistics using weighted coefficients and a forgetting curve.
Rethinking the logistic approach for population dynamics of mutualistic interactions.
García-Algarra, Javier; Galeano, Javier; Pastor, Juan Manuel; Iriondo, José María; Ramasco, José J
2014-12-21
Mutualistic communities have an internal structure that makes them resilient to external perturbations. Late research has focused on their stability and the topology of the relations between the different organisms to explain the reasons of the system robustness. Much less attention has been invested in analyzing the systems dynamics. The main population models in use are modifications of the r-K formulation of logistic equation with additional terms to account for the benefits produced by the interspecific interactions. These models have shortcomings as the so-called r-K formulation diverges under some conditions. In this work, we introduce a model for population dynamics under mutualism that preserves the original logistic formulation. It is mathematically simpler than the widely used type II models, although it shows similar complexity in terms of fixed points and stability of the dynamics. We perform an analytical stability analysis and numerical simulations to study the model behavior in general interaction scenarios including tests of the resilience of its dynamics under external perturbations. Despite its simplicity, our results indicate that the model dynamics shows an important richness that can be used to gain further insights in the dynamics of mutualistic communities.
Fixed point theorems for compatible mappings of type (P and applications to dynamic programming
Directory of Open Access Journals (Sweden)
H. K. Pathak
1995-11-01
Full Text Available In this paper, we prove some common fixed point theorems for compatible mappings of type (P. As applications, the existence and uniqueness of common solutions for a class of the functional equations in dynamic programming are discussed.
An innovative approach for testing bioinformatics programs using metamorphic testing
Directory of Open Access Journals (Sweden)
Liu Huai
2009-01-01
Full Text Available Abstract Background Recent advances in experimental and computational technologies have fueled the development of many sophisticated bioinformatics programs. The correctness of such programs is crucial as incorrectly computed results may lead to wrong biological conclusion or misguide downstream experimentation. Common software testing procedures involve executing the target program with a set of test inputs and then verifying the correctness of the test outputs. However, due to the complexity of many bioinformatics programs, it is often difficult to verify the correctness of the test outputs. Therefore our ability to perform systematic software testing is greatly hindered. Results We propose to use a novel software testing technique, metamorphic testing (MT, to test a range of bioinformatics programs. Instead of requiring a mechanism to verify whether an individual test output is correct, the MT technique verifies whether a pair of test outputs conform to a set of domain specific properties, called metamorphic relations (MRs, thus greatly increases the number and variety of test cases that can be applied. To demonstrate how MT is used in practice, we applied MT to test two open-source bioinformatics programs, namely GNLab and SeqMap. In particular we show that MT is simple to implement, and is effective in detecting faults in a real-life program and some artificially fault-seeded programs. Further, we discuss how MT can be applied to test programs from various domains of bioinformatics. Conclusion This paper describes the application of a simple, effective and automated technique to systematically test a range of bioinformatics programs. We show how MT can be implemented in practice through two real-life case studies. Since many bioinformatics programs, particularly those for large scale simulation and data analysis, are hard to test systematically, their developers may benefit from using MT as part of the testing strategy. Therefore our work
Sumner, Isaiah; Iyengar, Srinivasan S
2007-10-18
We have introduced a computational methodology to study vibrational spectroscopy in clusters inclusive of critical nuclear quantum effects. This approach is based on the recently developed quantum wavepacket ab initio molecular dynamics method that combines quantum wavepacket dynamics with ab initio molecular dynamics. The computational efficiency of the dynamical procedure is drastically improved (by several orders of magnitude) through the utilization of wavelet-based techniques combined with the previously introduced time-dependent deterministic sampling procedure measure to achieve stable, picosecond length, quantum-classical dynamics of electrons and nuclei in clusters. The dynamical information is employed to construct a novel cumulative flux/velocity correlation function, where the wavepacket flux from the quantized particle is combined with classical nuclear velocities to obtain the vibrational density of states. The approach is demonstrated by computing the vibrational density of states of [Cl-H-Cl]-, inclusive of critical quantum nuclear effects, and our results are in good agreement with experiment. A general hierarchical procedure is also provided, based on electronic structure harmonic frequencies, classical ab initio molecular dynamics, computation of nuclear quantum-mechanical eigenstates, and employing quantum wavepacket ab initio dynamics to understand vibrational spectroscopy in hydrogen-bonded clusters that display large degrees of anharmonicities.
An Approach to Effortless Construction of Program Animations
Velazquez-Iturbide, J. Angel; Pareja-Flores, Cristobal; Urquiza-Fuentes, Jaime
2008-01-01
Program animation systems have not been as widely adopted by computer science educators as we might expect from the firm belief that they can help in enhancing computer science education. One of the most notable obstacles to their adoption is the considerable effort that the production of program animations represents for the instructor. We…
Winning One Program at a Time: A Systemic Approach
Schultz, Adam; Zimmerman, Kay
2016-01-01
Many Universities are missing an opportunity to focus student recruitment marketing efforts and budget at the program level, which can offer lower priced advertising opportunities with higher conversion rates than traditional University level marketing initiatives. At NC State University, we have begun to deploy a scalable, low-cost, program level…
Prevalent Approaches to Professional Development in State 4-H Programs
Smith, Martin H.; Worker, Steven M.; Schmitt-McQuitty, Lynn; Meehan, Cheryl L.; Lewis, Kendra M.; Schoenfelder, Emily; Brian, Kelley
High-quality 4-H programming requires effective professional development of educators. Through a mixed methods study, we explored professional development offered through state 4-H programs. Survey results revealed that both in-person and online delivery modes were used commonly for 4-H staff and adult volunteers; for teen volunteers, in-person…
Teen Risk-Taking: Promising Prevention Programs and Approaches.
Eisen, Marvin; Pallitto, Christina; Bradner, Carolyn; Bolshun, Natalya
This guidebook explores some of the practical issues associated with finding, choosing, and starting potentially effective prevention programs for at-risk preteens and teens. The guidebook is based on a study of 51 intervention programs that identified elements and delivery mechanisms that were associated with their effectiveness. A closer look at…
An Approach to Effortless Construction of Program Animations
Velazquez-Iturbide, J. Angel; Pareja-Flores, Cristobal; Urquiza-Fuentes, Jaime
2008-01-01
Program animation systems have not been as widely adopted by computer science educators as we might expect from the firm belief that they can help in enhancing computer science education. One of the most notable obstacles to their adoption is the considerable effort that the production of program animations represents for the instructor. We…
Ideas in Practice: Toward a Participatory Approach to Program Assessment
Bruch, Patrick L.; Reynolds, Thomas
2012-01-01
Drawing on critical multicultural education scholarship, this article discusses an alternative assessment of academic support programs. It highlights the importance and value of supplementing traditional assessments with direct student participation. Through a discussion of data from a summer bridge program at a large research university, the…
Institute of Scientific and Technical Information of China (English)
陈志平
2003-01-01
A new deterministic formulation,called the conditional expectation formulation,is proposed for dynamic stochastic programming problems in order to overcome some disadvantages of existing deterministic formulations.We then check the impact of the new deterministic formulation and other two deterministic formulations on the corresponding problem size,nonzero elements and solution time by solving some typical dynamic stochastic programming problems with different interior point algorithms.Numerical results show the advantage and application of the new deterministic formulation.
EDISON-WMW: Exact Dynamic Programing Solution of the Wilcoxon–Mann–Whitney Test
Directory of Open Access Journals (Sweden)
Alexander Marx
2016-02-01
Full Text Available In many research disciplines, hypothesis tests are applied to evaluate whether findings are statistically significant or could be explained by chance. The Wilcoxon–Mann–Whitney (WMW test is among the most popular hypothesis tests in medicine and life science to analyze if two groups of samples are equally distributed. This nonparametric statistical homogeneity test is commonly applied in molecular diagnosis. Generally, the solution of the WMW test takes a high combinatorial effort for large sample cohorts containing a significant number of ties. Hence, P value is frequently approximated by a normal distribution. We developed EDISON-WMW, a new approach to calculate the exact permutation of the two-tailed unpaired WMW test without any corrections required and allowing for ties. The method relies on dynamic programing to solve the combinatorial problem of the WMW test efficiently. Beyond a straightforward implementation of the algorithm, we presented different optimization strategies and developed a parallel solution. Using our program, the exact P value for large cohorts containing more than 1000 samples with ties can be calculated within minutes. We demonstrate the performance of this novel approach on randomly-generated data, benchmark it against 13 other commonly-applied approaches and moreover evaluate molecular biomarkers for lung carcinoma and chronic obstructive pulmonary disease (COPD. We found that approximated P values were generally higher than the exact solution provided by EDISON-WMW. Importantly, the algorithm can also be applied to high-throughput omics datasets, where hundreds or thousands of features are included. To provide easy access to the multi-threaded version of EDISON-WMW, a web-based solution of our algorithm is freely available at http://www.ccb.uni-saarland.de/software/wtest/.
EDISON-WMW:Exact Dynamic Programing Solution of the Wilcoxon-Mann-Whitney Test
Institute of Scientific and Technical Information of China (English)
Alexander Marx; Christina Backes; Eckart Meese; Hans-Peter Lenhof; Andreas Keller
2016-01-01
In many research disciplines, hypothesis tests are applied to evaluate whether findings are statistically significant or could be explained by chance. The Wilcoxon–Mann–Whitney (WMW) test is among the most popular hypothesis tests in medicine and life science to analyze if two groups of samples are equally distributed. This nonparametric statistical homogeneity test is commonly applied in molecular diagnosis. Generally, the solution of the WMW test takes a high combinatorial effort for large sample cohorts containing a significant number of ties. Hence, P value is frequently approximated by a normal distribution. We developed EDISON-WMW, a new approach to calcu-late the exact permutation of the two-tailed unpaired WMW test without any corrections required and allowing for ties. The method relies on dynamic programing to solve the combinatorial problem of the WMW test efficiently. Beyond a straightforward implementation of the algorithm, we pre-sented different optimization strategies and developed a parallel solution. Using our program, the exact P value for large cohorts containing more than 1000 samples with ties can be calculated within minutes. We demonstrate the performance of this novel approach on randomly-generated data, benchmark it against 13 other commonly-applied approaches and moreover evaluate molec-ular biomarkers for lung carcinoma and chronic obstructive pulmonary disease (COPD). We found that approximated P values were generally higher than the exact solution provided by EDISONWMW. Importantly, the algorithm can also be applied to high-throughput omics datasets, where hundreds or thousands of features are included. To provide easy access to the multi-threaded version of EDISON-WMW, a web-based solution of our algorithm is freely available at http:// www.ccb.uni-saarland.de/software/wtest/.
EDISON-WMW: Exact Dynamic Programing Solution of the Wilcoxon-Mann-Whitney Test.
Marx, Alexander; Backes, Christina; Meese, Eckart; Lenhof, Hans-Peter; Keller, Andreas
2016-02-01
In many research disciplines, hypothesis tests are applied to evaluate whether findings are statistically significant or could be explained by chance. The Wilcoxon-Mann-Whitney (WMW) test is among the most popular hypothesis tests in medicine and life science to analyze if two groups of samples are equally distributed. This nonparametric statistical homogeneity test is commonly applied in molecular diagnosis. Generally, the solution of the WMW test takes a high combinatorial effort for large sample cohorts containing a significant number of ties. Hence, P value is frequently approximated by a normal distribution. We developed EDISON-WMW, a new approach to calculate the exact permutation of the two-tailed unpaired WMW test without any corrections required and allowing for ties. The method relies on dynamic programing to solve the combinatorial problem of the WMW test efficiently. Beyond a straightforward implementation of the algorithm, we presented different optimization strategies and developed a parallel solution. Using our program, the exact P value for large cohorts containing more than 1000 samples with ties can be calculated within minutes. We demonstrate the performance of this novel approach on randomly-generated data, benchmark it against 13 other commonly-applied approaches and moreover evaluate molecular biomarkers for lung carcinoma and chronic obstructive pulmonary disease (COPD). We found that approximated P values were generally higher than the exact solution provided by EDISON-WMW. Importantly, the algorithm can also be applied to high-throughput omics datasets, where hundreds or thousands of features are included. To provide easy access to the multi-threaded version of EDISON-WMW, a web-based solution of our algorithm is freely available at http://www.ccb.uni-saarland.de/software/wtest/.
DYNAMICS OF KNOWLEDGE ACCUMULATION IN TECHNOLOGY FOLLOWER COUNTRIES: A SYSTEM DYNAMICS APPROACH
Institute of Scientific and Technical Information of China (English)
Ehsan SHAFIEI; Mohammad-Bagher GHOFRANI; Yadollah SABOOHI
2009-01-01
In this paper the process of knowledge accumulation for a particular technology is studied. Two countries, say the technology follower and the technology frontier, are considered. The frontier's knowledge growth is determined by its R&D efforts on the technology. The level of knowledge stock for the follower countryis augmented by its R&D activities for the technology and absorbing some of the external knowledge through spillover from the frontier. The extent to which the follower is able to exploit the external knowledge depends on technological gap, absorptive capacity, absorption time and degree of spillover. New concepts such as natural and enhanced degree of spillover, background and innovative knowledge and absorption speed are introduced in the present work to deeply explore the process of knowledge spillover. The factors influencing the knowledge development in the long term are simultaneously studied in an integrated structure provided by the System Dynamics approach. This framework shows the responses to the changes and provides the basis for examining the interactions among the variables over time.
Low-temperature hopping dynamics with energy disorder: renormalization group approach.
Velizhanin, Kirill A; Piryatinski, Andrei; Chernyak, Vladimir Y
2013-08-28
We formulate a real-space renormalization group (RG) approach for efficient numerical analysis of the low-temperature hopping dynamics in energy-disordered lattices. The approach explicitly relies on the time-scale separation of the trapping/escape dynamics. This time-scale separation allows to treat the hopping dynamics as a hierarchical process, RG step being a transformation between the levels of the hierarchy. We apply the proposed RG approach to analyze hopping dynamics in one- and two-dimensional lattices with varying degrees of energy disorder, and find the approach to be accurate at low temperatures and computationally much faster than the brute-force direct diagonalization. Applicability criteria of the proposed approach with respect to the time-scale separation and the maximum number of hierarchy levels are formulated. RG flows of energy distribution and pre-exponential factors of the Miller-Abrahams model are analyzed.
Davidsen, Claus; Liu, Suxia; Mo, Xingguo; Rosbjerg, Dan; Bauer-Gottwein, Peter
2014-05-01
Optimal management of conjunctive use of surface water and groundwater has been attempted with different algorithms in the literature. In this study, a hydro-economic modelling approach to optimize conjunctive use of scarce surface water and groundwater resources under uncertainty is presented. A stochastic dynamic programming (SDP) approach is used to minimize the basin-wide total costs arising from water allocations and water curtailments. Dynamic allocation problems with inclusion of groundwater resources proved to be more complex to solve with SDP than pure surface water allocation problems due to head-dependent pumping costs. These dynamic pumping costs strongly affect the total costs and can lead to non-convexity of the future cost function. The water user groups (agriculture, industry, domestic) are characterized by inelastic demands and fixed water allocation and water supply curtailment costs. As in traditional SDP approaches, one step-ahead sub-problems are solved to find the optimal management at any time knowing the inflow scenario and reservoir/aquifer storage levels. These non-linear sub-problems are solved using a genetic algorithm (GA) that minimizes the sum of the immediate and future costs for given surface water reservoir and groundwater aquifer end storages. The immediate cost is found by solving a simple linear allocation sub-problem, and the future costs are assessed by interpolation in the total cost matrix from the following time step. Total costs for all stages, reservoir states, and inflow scenarios are used as future costs to drive a forward moving simulation under uncertain water availability. The use of a GA to solve the sub-problems is computationally more costly than a traditional SDP approach with linearly interpolated future costs. However, in a two-reservoir system the future cost function would have to be represented by a set of planes, and strict convexity in both the surface water and groundwater dimension cannot be maintained