265 research outputs found

    Distributed Response Time Analysis of GSPN Models with MapReduce

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    widely used in the performance analysis of computer and communications systems. Response time densities and quantiles are often key outputs of such analysis. These can be extracted from a GSPN’s underlying semi-Markov process using a method based on numerical Laplace transform inversion. This method typically requires the solution of thousands of systems of complex linear equations, each of rank n, where n is the number of states in the model. For large models substantial processing power is needed and the computation must therefore be distributed. This paper describes the implementation of a Response Time Analysis module for the Platform Independent Petri net Editor (PIPE2) which interfaces with Hadoop, an open source implementation of Google’s MapReduce distributed programming environment, to provide distributed calculation of response time densities in GSPN models. The software is validated with analytically calculated results as well as simulated ones for larger models. Excellent scalability is shown. I

    Leo: Lagrange Elementary Optimization

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    Global optimization problems are frequently solved using the practical and efficient method of evolutionary sophistication. But as the original problem becomes more complex, so does its efficacy and expandability. Thus, the purpose of this research is to introduce the Lagrange Elementary Optimization (Leo) as an evolutionary method, which is self-adaptive inspired by the remarkable accuracy of vaccinations using the albumin quotient of human blood. They develop intelligent agents using their fitness function value after gene crossing. These genes direct the search agents during both exploration and exploitation. The main objective of the Leo algorithm is presented in this paper along with the inspiration and motivation for the concept. To demonstrate its precision, the proposed algorithm is validated against a variety of test functions, including 19 traditional benchmark functions and the CECC06 2019 test functions. The results of Leo for 19 classic benchmark test functions are evaluated against DA, PSO, and GA separately, and then two other recent algorithms such as FDO and LPB are also included in the evaluation. In addition, the Leo is tested by ten functions on CECC06 2019 with DA, WOA, SSA, FDO, LPB, and FOX algorithms distinctly. The cumulative outcomes demonstrate Leo's capacity to increase the starting population and move toward the global optimum. Different standard measurements are used to verify and prove the stability of Leo in both the exploration and exploitation phases. Moreover, Statistical analysis supports the findings results of the proposed research. Finally, novel applications in the real world are introduced to demonstrate the practicality of Leo.Comment: 28 page

    Performability: a retrospective and some pointers to the future

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    As computing and communication systems become physically and logically more complex, their evaluation calls for continued innovation with regard to measure definition, model construction/solution, and tool development. In particular, the performance of such systems is often degradable, i.e., internal or external faults can reduce the quality of a delivered service even though that service, according to its specification, remains proper (failure-free). The need to accommodate this property, using model-based evaluation methods, was the raison d'etre for the concept of performability. To set the stage for additional progress in its development, we present a retrospective of associated theory, techniques, and applications resulting from work in this area over the past decade and a half. Based on what has been learned, some pointers are made to future directions which might further enhance the effectiveness of these methods and broaden their scope of applicability.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30223/1/0000615.pd

    34th Midwest Symposium on Circuits and Systems-Final Program

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    Organized by the Naval Postgraduate School Monterey California. Cosponsored by the IEEE Circuits and Systems Society. Symposium Organizing Committee: General Chairman-Sherif Michael, Technical Program-Roberto Cristi, Publications-Michael Soderstrand, Special Sessions- Charles W. Therrien, Publicity: Jeffrey Burl, Finance: Ralph Hippenstiel, and Local Arrangements: Barbara Cristi

    Tools and Algorithms for the Construction and Analysis of Systems

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    This book is Open Access under a CC BY licence. The LNCS 11427 and 11428 proceedings set constitutes the proceedings of the 25th International Conference on Tools and Algorithms for the Construction and Analysis of Systems, TACAS 2019, which took place in Prague, Czech Republic, in April 2019, held as part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2019. The total of 42 full and 8 short tool demo papers presented in these volumes was carefully reviewed and selected from 164 submissions. The papers are organized in topical sections as follows: Part I: SAT and SMT, SAT solving and theorem proving; verification and analysis; model checking; tool demo; and machine learning. Part II: concurrent and distributed systems; monitoring and runtime verification; hybrid and stochastic systems; synthesis; symbolic verification; and safety and fault-tolerant systems

    Proceedings of SAT Competition 2021 : Solver and Benchmark Descriptions

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    Non peer reviewe

    stochastic modeling and analysis of 3g mobile communication systems

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    Third-generation (3G) mobile communication systems are currently one of the key communication technologies in research and development due to the high market demand for advanced wireless communication. The current evolution is primarily characterized by a transition from circuit-switched voice-oriented networks to integrated multi-service all IP networks. To effectively design complex mobile communication systems, the design process should be accompanied by stochastic modeling and quantitative evaluation of different design alternatives. The most popular language for model specification used in industrial projects is the Unified Modeling Language (UML). Although conceived as a general-purpose modeling language, the current version of the UML does not contain building blocks for introducing stochastic timing into UML diagrams.The first part of this thesis presents new results for numerical quantitative analysis of discrete-event stochastic systems specified in Petri net notation or as UML diagrams. An efficient algorithm for the state space generation out of an UML state diagram or activity diagram that allows quantitative analysis by means of the underlying stochastic process is presented. Furthermore, this thesis considers new methodological results for the effective numerical analysis of finite-state generalized semi-Markov processes with exponential and deterministic events by an embedded general state space Markov chain (GSSMC). Key contributions constitute (i) the observation that elements of the transition kernel of the GSSMC can always be computed by appropriate summation of transient state probabilities of continuous-time Markov chains and (ii) the derivation of conditions under which kernel elements are constant. To provide automated tool support, the presented algorithms are included in the software package DSPNexpress-NG available for download on the Web.The support of multimedia services over wireless channels presents a number of technical challenges. One of the major challenges is to effectively utilize the scarce radio bandwidth in the access network by adaptive control of system parameters. The second part of this thesis is devoted to this topic. A Markov model representing the sharing of radio channels by circuit-switched connections and packet-switched sessions under a dynamic channel allocation scheme is evaluated. Closing the loop between network operation and network control, a framework for the adaptive quality of service management for 3G mobile networks is introduced. Building on this framework, a novel call admission control and bandwidth reservation scheme for the optimization of quality of service for mobile subscribers is presented. The performance of the solutions proposed in this thesis is investigated experimentally based on numerical quantitative analysis and discrete-event simulation
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