The Experts below are selected from a list of 8082 Experts worldwide ranked by ideXlab platform
Q. Wang - One of the best experts on this subject based on the ideXlab platform.
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Constraint Violation detection: a fundamental part of software cybernetics
29th Annual International Computer Software and Applications Conference (COMPSAC'05), 2005Co-Authors: Q. WangAbstract:Monitoring of sensitive events is a key step for controlling the behavior of software. Specifying a sufficient set of Constraints prior to software deployment is necessary for detecting the presence of such events during execution. Here we focus on issues related to service level Constraints including types of Constraints, the runtime structure of Constraints and the related entities. An experiment to assess the feasibility of the proposed approach is also reported.
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Interceptor based Constraint Violation detection
12th IEEE International Conference and Workshops on the Engineering of Computer-Based Systems (ECBS'05), 2005Co-Authors: Q. Wang, Aditya MathurAbstract:Monitoring critical events such as Constraints Violations is one of the key issues of autonomic systems. This paper presents an interceptor based approach of Constraint Violation detection. In our approach, the monitor code is independent of functional code, and the monitor code can be generated automatically from XML-based Constraint specifications. The experiment shows that our approach is feasible and is especially suitable for interface level Constraints.
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ECBS - Interceptor based Constraint Violation detection
12th IEEE International Conference and Workshops on the Engineering of Computer-Based Systems (ECBS'05), 2005Co-Authors: Q. Wang, Aditya P. MathurAbstract:Monitoring critical events such as Constraints Violations is one of the key issues of autonomic systems. This paper presents an interceptor based approach of Constraint Violation detection. In our approach, the monitor code is independent of functional code, and the monitor code can be generated automatically from XML-based Constraint specifications. The experiment shows that our approach is feasible and is especially suitable for interface level Constraints.
Jeffrey Scott Vitter - One of the best experts on this subject based on the ideXlab platform.
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STOC - e-approximations with minimum packing Constraint Violation (extended abstract)
Proceedings of the twenty-fourth annual ACM symposium on Theory of computing - STOC '92, 1992Co-Authors: Jeffrey Scott VitterAbstract:We present efficient new randomized and deterministic methods for transforming optimal solutions for a type of relaxed integer linear program into provably good solutions for the corresponding NP -hard discrete optimization problem. Without any Constraint Violation, the e-approximation problem for many problems of this type is itself NP -hard. Our methods provide polynomial-time e-approximations while attempting to minimize the packing Constraint Violation. Our methods lead to the first known approximation algorithms with provable performance guarantees for the s-median problem , the tree prunning problem , and the generalized assignment problem . These important problems have numerous applications to data compression, vector quantization, memory-based learning, computer graphics, image processing, clustering, regression, network location, scheduling, and communication. We provide evidence via reductions that our approximation algorithms are nearly optimal in terms of the packing Constraint Violation. We also discuss some recent applications of our techniques to scheduling problems.
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e approximations with minimum packing Constraint Violation extended abstract
Symposium on the Theory of Computing, 1992Co-Authors: Jeffrey Scott VitterAbstract:We present efficient new randomized and deterministic methods for transforming optimal solutions for a type of relaxed integer linear program into provably good solutions for the corresponding NP -hard discrete optimization problem. Without any Constraint Violation, the e-approximation problem for many problems of this type is itself NP -hard. Our methods provide polynomial-time e-approximations while attempting to minimize the packing Constraint Violation. Our methods lead to the first known approximation algorithms with provable performance guarantees for the s-median problem , the tree prunning problem , and the generalized assignment problem . These important problems have numerous applications to data compression, vector quantization, memory-based learning, computer graphics, image processing, clustering, regression, network location, scheduling, and communication. We provide evidence via reductions that our approximation algorithms are nearly optimal in terms of the packing Constraint Violation. We also discuss some recent applications of our techniques to scheduling problems.
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approximations with minimum packing Constraint Violation
1992Co-Authors: Jeffrey Scott VitterAbstract:We present efficient new randomized and deterministic methods for transforming optimal solutions for a type of relaxed integer linear program into provably good solutions for the corresponding NP-hard discrete optimization problem. Without any Constraint Violation, the epsilon-approximation problem for many problems of this type is itself NP-hard. Our methods provide polynomial-time epsilon-approximations while attempting to minimize the packing Constraint Violation. Our methods lead to the first known approximation algorithms with provable performance guarantees for the s-median problem, the tree pruning problem, and the generalized assignment problem. These important problems have numerous applications to data compression, vector quantization, memory-based learning, computer graphics, image processing, clustering, regression, network location, scheduling, protocol testing, and communication. We provide evidence via reductions that our approximation algorithms are nearly optimal in terms of the packing Constraint Violation. We also discuss some recent applications of our techniques to scheduling problems.
S. Weiland - One of the best experts on this subject based on the ideXlab platform.
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Optimal control of linear, stochastic systems with state and input Constraints
Proceedings of the 41st IEEE Conference on Decision and Control 2002., 2002Co-Authors: I. Batina, A.a. Stoorvogel, S. WeilandAbstract:In this paper we extend the work presented in our previous papers (2001) where we considered optimal control of a linear, discrete time system subject to input Constraints and stochastic disturbances. Here we basically look at the same problem but we additionally consider state Constraints. We discuss several approaches for incorporating state Constraints in a stochastic optimal control problem. We consider in particular a soft-Constraint on the state Constraints where Constraint Violation is punished by a hefty penalty in the cost function. Because of the stochastic nature of the problem, the penalty on the state Constraint Violation can not be made arbitrary high. We derive a condition on the growth of the state Violation cost that has to be satisfied for the optimization problem to be solvable. This condition gives a link between the problem that we consider and the well known H/sub /spl infin// control problem.
Claus Pahl - One of the best experts on this subject based on the ideXlab platform.
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IEEE SCC - Integrated Constraint Violation Handling for Dynamic Service Composition
2009 IEEE International Conference on Services Computing, 2009Co-Authors: Mingxue Wang, Kosala Yapa Bandara, Claus PahlAbstract:Dynamic service composition is suitable for on-demand business requests. For autonomic computing, service composition needs to deal with runtime environment faults, but also with business Constraint Violations which result from business requirements. We propose an approach for integrated handling of business Constraint Violations and runtime environment faults for dynamic service composition.We introduce a loosely coupled implementation architecture to maintain the platform-independent nature.
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Integrated Constraint Violation Handling for Dynamic Service Composition
2009 IEEE International Conference on Services Computing, 2009Co-Authors: Mingxue Wang, Kosala Yapa Bandara, Claus PahlAbstract:Dynamic service composition is suitable for on-demand business requests. For autonomic computing, service composition needs to deal with runtime environment faults, but also with business Constraint Violations which result from business requirements. We propose an approach for integrated handling of business Constraint Violations and runtime environment faults for dynamic service composition.We introduce a loosely coupled implementation architecture to maintain the platform independent nature.
Wojciech Blajer - One of the best experts on this subject based on the ideXlab platform.
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methods for Constraint Violation suppression in the numerical simulation of constrained multibody systems a comparative study
Computer Methods in Applied Mechanics and Engineering, 2011Co-Authors: Wojciech BlajerAbstract:Abstract Multibody systems are frequently modeled as constrained systems, and the arising governing equations incorporate the closing Constraint equations at the acceleration level. One consequence of accumulation of integration truncation errors is the phenomenon of Violation of the lower-order Constraint equations by the numerical solutions to the governing equations. The Constraint drift usually tends to increase in time and may spoil reliability of the simulation results. In this paper a comparative study of three methods for Constraint Violation suppression is presented: the popular Baumgarte’s Constraint Violation stabilization method, a projective scheme for Constraint Violation elimination, and a novel scheme patterned after that proposed recently by Braun and Goldfarb [D.J. Braun, M. Goldfarb, Eliminating Constraint drift in the numerical simulation of constrained dynamical systems, Comput. Meth. Appl. Mech. Engrg., 198 (2009) 3151–3160]. The methods are confronted with respect to simplicity in applications, numerical effectiveness and influence on accuracy of the Constraint-consistent motion.
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Methods for Constraint Violation suppression in the numerical simulation of constrained multibody systems – A comparative study
Computer Methods in Applied Mechanics and Engineering, 2011Co-Authors: Wojciech BlajerAbstract:Abstract Multibody systems are frequently modeled as constrained systems, and the arising governing equations incorporate the closing Constraint equations at the acceleration level. One consequence of accumulation of integration truncation errors is the phenomenon of Violation of the lower-order Constraint equations by the numerical solutions to the governing equations. The Constraint drift usually tends to increase in time and may spoil reliability of the simulation results. In this paper a comparative study of three methods for Constraint Violation suppression is presented: the popular Baumgarte’s Constraint Violation stabilization method, a projective scheme for Constraint Violation elimination, and a novel scheme patterned after that proposed recently by Braun and Goldfarb [D.J. Braun, M. Goldfarb, Eliminating Constraint drift in the numerical simulation of constrained dynamical systems, Comput. Meth. Appl. Mech. Engrg., 198 (2009) 3151–3160]. The methods are confronted with respect to simplicity in applications, numerical effectiveness and influence on accuracy of the Constraint-consistent motion.
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Elimination of Constraint Violation and Accuracy Aspects in Numerical Simulation of Multibody Systems
Multibody System Dynamics, 2002Co-Authors: Wojciech BlajerAbstract:Multibody systems are often modeled as constrained systems, and theConstraint equations are involved in the dynamics formulations. To makethe arising governing equations more tractable, the Constraint equationsare differentiated with respect to time, and this results in unstablenumerical solutions which may violate the lower-order Constraintequations. In this paper we develop a methodology for numerically exactelimination of the Constraint Violations, based on appropriatecorrections of the state variables (after each integration step) withoutany modification in the motion equations. While the elimination ofViolation of position Constraints may require few iterations, theViolation of velocity Constraints is removed in one step. The totalenergy of the system is sometimes treated as another measure of theintegration process inaccuracy. An improved scheme for one-stepelimination of the energy Constraint Violation is proposed as well. Theconclusion of this paper is, however, that the energy conservation is ofminor importance as concerns the improvement of accuracy of numericalsimulations. Some test calculations are reported.