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GreatSPN 1.7: GRaphical Editor and Analyzer for Timed and Stochastic Petri Nets
, 1995
"... This paper describes the GreatSPN 1.7 package for the modeling, validation, and performance evaluation of distributed systems using Generalized Stochastic Petri Nets and their colored extension. The tool provides a friendly framework to experiment with timed Petri net based modeling techniques. It i ..."
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Cited by 99 (17 self)
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This paper describes the GreatSPN 1.7 package for the modeling, validation, and performance evaluation of distributed systems using Generalized Stochastic Petri Nets and their colored extension. The tool provides a friendly framework to experiment with timed Petri net based modeling techniques. It implements efficient analysis algorithms to allow its use on "real" applications, not only toy examples. Developed in a University for non profit purposes, it is distributed free of charge to other universities for educational and research purposes. An overview of the complete architecture of the package is given together with examples of its application. Then the various analysis and simulation modules are described. 1 Introduction GreatSPN 1.7 is a tool for the modeling and analysis of systems, based on the Petri net formalism. In this paper we first briefly describe the historical evolution of the package, which explains the reasons for some implementation choices as well as the intended p...
Numerical Analysis of Superposed GSPNs
 IEEE TRANSACTIONS ON SOFTWARE ENGINEERING
, 1996
"... The numerical analysis of various modeling formalisms profits from a structured representation for the generator matrix Q of the underlying continuous time Markov chain, where Q is described by a sum of tensor (Kronecker) products of much smaller matrices. In this paper we describe such a representa ..."
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Cited by 71 (10 self)
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The numerical analysis of various modeling formalisms profits from a structured representation for the generator matrix Q of the underlying continuous time Markov chain, where Q is described by a sum of tensor (Kronecker) products of much smaller matrices. In this paper we describe such a representation for the class of superposed generalized stochastic Petri nets (SGSPNs), which is less restrictive than in previous work. Furthermore a new iterative analysis algorithm is proposed. It pays special attention to a memory efficient representation of iteration vectors as well as to a memory efficient structured representation of Q. In consequence the new algorithm is able to solve models which have state spaces with several millions of states, where other exact numerical methods become impracticable on a common workstation.
QPNTool for the Specification and Analysis of Hierarchically Combined Queueing Petri Nets
 BAUSE (EDS.) QUANTITATIVE EVALUATION OF COMPUTING AND COMMUNICATION SYSTEMS, LECTURE NOTES IN COMPUTER SCIENCE
, 1995
"... This article describes a new version of the QPNTool now supporting specification and analysis of hierarchically combined Queueing Petri nets (HQPNs). HQPNs are an extension of QPNs allowing the refinement of places by QPN subnets and/or queues. HQPNs can be analysed with respect to qualitative ..."
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Cited by 27 (4 self)
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This article describes a new version of the QPNTool now supporting specification and analysis of hierarchically combined Queueing Petri nets (HQPNs). HQPNs are an extension of QPNs allowing the refinement of places by QPN subnets and/or queues. HQPNs can be analysed with respect to qualitative and quantitative aspects. Quantitative analysis is based on numerical Markov chain analysis. In contrast to conventional techniques the Markov chain underlying a HQPN is analysed by an approach exploiting the hierarchical structure of the model which results in a tensor representation of the generator matrix. This technique extends the size of solvable state spaces by one order of magnitude. Qualitative analysis of HQPNs relies on efficient analysis techniques based on Petri net theory. The new version of QPNTool implements the above analysis approaches supported by a graphical interface for a convenient specification of complex models.
Specification Techniques for Markov Reward Models
 in Discrete Event Dynamic Systems: Theory and Applications 3:219–247
, 1993
"... Abstract. Markov reward models (MRMs) are commonly used for the performance, dependability, and performability analysis of computer and communication systems. Many papers have addressed solution techniques for MRMs. Far less attention has been paid to the specification of MRMs and the subsequent de ..."
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Cited by 25 (1 self)
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Abstract. Markov reward models (MRMs) are commonly used for the performance, dependability, and performability analysis of computer and communication systems. Many papers have addressed solution techniques for MRMs. Far less attention has been paid to the specification of MRMs and the subsequent derivation of the underlying MRM. In this paper we only briefly address the mathematical aspects of MRMs. Instead, emphasis is put on specification techniques. In an application independent way, we distinguish seven classes of specification techniques: stochastic Petri nets, queuing networks, fault trees, production rule systems, communicating processes, specialized languages, and hybrid techniques. For these seven classes, we discuss the main principles, give examples and discuss software tools that support the use of these techniques. An overview like this has not been presented in the literature before. Finally, the paper addresses the generation of the underiying MRM from the highlevel specification, and indicates important future research areas.
Transient Analysis of Deterministic and Stochastic Petri Nets with TimeNET
 Lecture Notes in Computer Science Vol. 977: Quantitative Evaluation of Computing and Communication Systems
, 1995
"... . This paper descibes the transient analysis component for deterministic and stochastic Petri nets which has recently been added to the software package TimeNET. The technique is based on the derivation of state equations by the method of supplementary variables. The system of equations consists of ..."
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Cited by 24 (5 self)
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. This paper descibes the transient analysis component for deterministic and stochastic Petri nets which has recently been added to the software package TimeNET. The technique is based on the derivation of state equations by the method of supplementary variables. The system of equations consists of partial and ordinary differential equations which are combined with initial and boundary conditions. Algorithms for the numerical analysis of the equations are presented. Emphasis is put on implementation aspects. Different cases are identified for which different variants of the algorithms can be used. The computational complexity is investigated by asymptotical expressions and by measurements. Several examples are used in order to illustrate the modeling process and transient analysis with TimeNET. 1 Introduction Stochastic Petri nets (SPNs) are well suited for the modelbased performance and dependability evaluation. Most commonly, the firing times of the transitions are exponentially di...
Recent Developments in NonMarkovian Stochastic Petri Nets
, 1998
"... Analytical modeling plays a crucial role in the analysis and design of computer systems. Stochastic Petri Nets represent a powerful paradigm, widely used for such modeling in the context of dependability, performance and performability. Many structural and stochastic extensions have been proposed in ..."
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Cited by 22 (4 self)
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Analytical modeling plays a crucial role in the analysis and design of computer systems. Stochastic Petri Nets represent a powerful paradigm, widely used for such modeling in the context of dependability, performance and performability. Many structural and stochastic extensions have been proposed in recent years to increase their modeling power, or their capability to handle large systems. This paper reviews recent developments by providing the theoretical background and the possible areas of application. Markovian Petri nets are first considered together with very well established extensions known as Generalized Stochastic Petri nets and Stochastic Reward Nets. Key ideas for coping with large state spaces are then discussed. The challenging area of nonMarkovian Petri nets is considered, and the related analysis techniques are surveyed together with the detailed elaboration of an example. Finally new models based on Continuous or Fluid Stochastic Petri Nets are briefly discussed.
MeasureAdaptive StateSpace Construction
, 2000
"... Measureadaptive statespace construction is the process of exploiting symmetry in highlevel model and performance measure specifications to automatically construct reduced statespace Markov models that support the evaluation of the performance measure. This paper describes a new reward variable s ..."
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Cited by 18 (1 self)
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Measureadaptive statespace construction is the process of exploiting symmetry in highlevel model and performance measure specifications to automatically construct reduced statespace Markov models that support the evaluation of the performance measure. This paper describes a new reward variable specification technique, which, combined with recently developed statespace construction techniques, will allow us to build tools capable of measureadaptive statespace construction. That is, these tools will automatically adapt the size of the state space to constraints derived from the system model and the userspecified reward variables. The work described in this paper extends previous work in two directions. First, standard reward variable definitions are extended to allow symmetry in the reward variable to be identified and exploited. Then, symmetric reward variables are further extended to include the set of pathbased reward variables described in earlier work. In addition to the theory, several examples are introduced to demonstrate these new techniques.
Performability modelling tools and techniques
, 1996
"... Over the last decade considerable effort has been put in the development of techniques to assess the performance and the dependability of computer and communication systems in an integrated way. This socalled performability modelling becomes especially useful when the system under study can operate ..."
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Cited by 17 (5 self)
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Over the last decade considerable effort has been put in the development of techniques to assess the performance and the dependability of computer and communication systems in an integrated way. This socalled performability modelling becomes especially useful when the system under study can operate partially, which is for instance the case for faulttolerant computer systems and distributed systems. Modelling techniques are a fundamental prerequisite for actually doing performability analysis. A prerequisite of a more practical but not less important nature is the availability of software tools to support the modelling techniques and to allow system designers to incorporate the new techniques in the design process of systems. Since performability modelling requires many aspects of a system to be specified, high requirements should be posed on perfotmability modelling tools. Moreover, these tools should be structured such that the models can be specified at a level that is easy to understand for a system designer, and that the mathematical aspects are hidden as much as possible. The output of the tool should also be such that it can be understood with only limited knowledge of the underlying mathematical model. We have developed a new, fairly general modelling tool framework that can be used as a guide to assess the usability and structure of performability modelling tools. After briefly reviewing the mathematical aspects of performability mcxlelling we discuss this framework. We then discuss 12 recently developed tools (Metaphor, Numas, Metasan, Metfac, Save, Sharpe, SPNP, Tangram, Penpet, UltraSAN, Surf2, DyQNtool+) that can all be used for some aspects of performability modelling and analysis. We assess among other things their structure, their capabilities in terms of measures that can be obtained, and the used modelling formalism. We also discuss directions for future work in the field of performability modelling tools.
Performance Evaluation for Parallel Systems: A Survey
, 1997
"... Performance is often a key factor in determining the success of a parallel software system. Performance evaluation... ..."
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Cited by 12 (0 self)
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Performance is often a key factor in determining the success of a parallel software system. Performance evaluation...
Steady State Solution of MRSPN with Mixed Preemption Policies
 In International Computer Performance and Dependability Symposium  IPDS96
, 1996
"... Markov Regenerative Stochastic Petri Nets (MRSPN) have been recently recognized as a valuable tool to model systems with nonexponential timed activities. The usual assumption in the implementation of such models is that at most a single nonexponential transition, with associated enabling memory ..."
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Cited by 9 (4 self)
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Markov Regenerative Stochastic Petri Nets (MRSPN) have been recently recognized as a valuable tool to model systems with nonexponential timed activities. The usual assumption in the implementation of such models is that at most a single nonexponential transition, with associated enabling memory policy, can be enabled in each marking. More recently, new memory policies have been studied in order to represent more complex and effective preemption mechanisms in real systems. Closedform solutions in the Laplace transform domain have been provided also in this case. This paper concentrates on the steadystate analysis of MRSPN and provides an unified analytical approach to include mixed memory policies into a single model. A numerical example concludes the paper. Key words: Stochastic Petri Nets, Markov regenerative processes, preemptive policies, steadystate analysis. 1 Introduction There is an increasing interest in the implementation of tools for performance/dependabilit...