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15
Probabilistic Symbolic Model Checking with PRISM: A Hybrid Approach
 International Journal on Software Tools for Technology Transfer (STTT
, 2002
"... In this paper we introduce PRISM, a probabilistic model checker, and describe the ecient symbolic techniques we have developed during its implementation. PRISM is a tool for analysing probabilistic systems. It supports three models: discretetime Markov chains, continuoustime Markov chains and ..."
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Cited by 137 (26 self)
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In this paper we introduce PRISM, a probabilistic model checker, and describe the ecient symbolic techniques we have developed during its implementation. PRISM is a tool for analysing probabilistic systems. It supports three models: discretetime Markov chains, continuoustime Markov chains and Markov decision processes. Analysis is performed through model checking speci cations in the probabilistic temporal logics PCTL and CSL. Motivated by the success of model checkers such as SMV, which use BDDs (binary decision diagrams), we have developed an implementation of PCTL and CSL model checking based on MTBDDs (multiterminal BDDs) and BDDs. Existing work in this direction has been hindered by the generally poor performance of MTBDDbased numerical computation, which is often substantially slower than explicit methods using sparse matrices. We present a novel hybrid technique which combines aspects of symbolic and explicit approaches to overcome these performance problems. For typical examples, we achieve orders of magnitude speedup compared to MTBDDs and are able to almost match the speed of sparse matrices whilst maintaining considerable space savings.
Implementation of Symbolic Model Checking for Probabilistic Systems
, 2002
"... In this thesis, we present ecient implementation techniques for probabilistic model checking, a method which can be used to analyse probabilistic systems such as randomised distributed algorithms, faulttolerant processes and communication networks. A probabilistic model checker inputs a probabilist ..."
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Cited by 50 (18 self)
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In this thesis, we present ecient implementation techniques for probabilistic model checking, a method which can be used to analyse probabilistic systems such as randomised distributed algorithms, faulttolerant processes and communication networks. A probabilistic model checker inputs a probabilistic model and a speci cation, such as \the message will be delivered with probability 1", \the probability of shutdown occurring is at most 0.02" or \the probability of a leader being elected within 5 rounds is at least 0.98", and can automatically verify if the speci cation is true in the model.
Performance analysis of probabilistic timed automata using digital clocks
 Proc. Formal Modeling and Analysis of Timed Systems (FORMATSâ€™03), volume 2791 of LNCS
, 2003
"... ..."
Symbolic Model Checking of Probabilistic Timed Automata Using Backwards Reachability
, 2000
"... We consider probabilistic timed automata of [13], an extension of the timed automata model of [2] with discrete probability distributions. In contrast to timed automata, which model realtime systems purely in terms of nondeterminism, our model allows to express the likelihood of the system makin ..."
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Cited by 49 (18 self)
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We consider probabilistic timed automata of [13], an extension of the timed automata model of [2] with discrete probability distributions. In contrast to timed automata, which model realtime systems purely in terms of nondeterminism, our model allows to express the likelihood of the system making certain transitions, and is thus appropriate for modelling faulttolerance and probabilistic failures. We present a symbolic model checking algorithm for the existential fragment of the logic PTCTL of [13] based on backward reachability as in [12]. The logic allows us to specify properties such as \with probability 0.99 or greater, it is possible to correctly deliver a data packet within 5 time units", or \with probability 0.87 or greater, the system never enters an error state".
Probabilistic Model Checking of Deadline Properties in the IEEE1394 FireWire Root Contention Protocol
 in the IEEE 1394 FireWire root contention protocol. Special Issue of Formal Aspects of Computing
"... The increasing dependence of businesses on distributed architectures and computer networking places heavy demands on the speed and reliability of data exchange, leading to the emergence of sophisticated protocols which involve both realtime and randomization, for example FireWire IEEE1394. Automati ..."
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Cited by 35 (23 self)
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The increasing dependence of businesses on distributed architectures and computer networking places heavy demands on the speed and reliability of data exchange, leading to the emergence of sophisticated protocols which involve both realtime and randomization, for example FireWire IEEE1394. Automatic verification techniques such as model checking have been adapted to this class of probabilistic, timed systems [1, 9, 3, 14]. This abstract considers an application of such techniques to the IEEE1394 (FireWire) root contention protocol, in which the interplay between timed and probabilistic aspects is used to break the symmetry which may arise during the leader election process. Here, the properties of interest concern the election of a leader within a certain deadline, with a certain probability or greater. Our specification formalism is that of probabilistic timed automata [14], a variant of timed automa...
Continuous Stochastic Logic Characterizes Bisimulation of Continuoustime Markov Processes
 J. of Logic and Alg. Progr
, 2002
"... In a recent paper Baier, Haverkort, Hermanns and Katoen [BHHK00], analyzed a new way of modelchecking formulas of a logic for continuoustime processes  called Continuous Stochastic Logic (henceforth CSL) { against continuoustime Markov chains { henceforth CTMCs. One of the important results o ..."
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Cited by 15 (3 self)
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In a recent paper Baier, Haverkort, Hermanns and Katoen [BHHK00], analyzed a new way of modelchecking formulas of a logic for continuoustime processes  called Continuous Stochastic Logic (henceforth CSL) { against continuoustime Markov chains { henceforth CTMCs. One of the important results of that paper was the proof that if two CTMCs were bisimilar then they would satisfy exactly the same formulas of CSL. This raises the converse question { does satisfaction of the same collection of CSL formulas imply bisimilarity? In other words, given two CTMCs which are known to satisfy exactly the same formulas of CSL does it have to be the case that they are bisimilar? We prove that the answer to the question just raised is \yes". In fact we prove a signi cant extension, namely that a subset of CSL suces even for systems where the statespace may be a continuum. Along the way we prove a result to the eect that the set of Zeno paths has measure zero provided that the transition rates are bounded.
Probabilistic KLAIM
 In Proc. of 7th International Conference on Coordination Models and Languages (Coordination 04), volume 2949 of LNCS
, 2004
"... We introduce a probabilistic extension of KLAIM, where the behaviour of networks and individual nodes is determined by a probabilistic scheduler for processes and probabilistic allocation environments which describe the logical neighbourhood of each node. The resulting language has two variants ..."
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Cited by 14 (5 self)
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We introduce a probabilistic extension of KLAIM, where the behaviour of networks and individual nodes is determined by a probabilistic scheduler for processes and probabilistic allocation environments which describe the logical neighbourhood of each node. The resulting language has two variants which are modelled respectively as discrete and continuous time Markov processes. We suggest that Poisson processes are a natural probabilistic model for the coordination of discrete processes asynchronously communicating in continuous time and we use them to de ne the operational semantics of the continuous time variant. This framework allows for the implementation of networks with independent clocks on each site.
Verifying Probabilistic Programs Using A Hoare Like Logic
, 2002
"... Probability, be it inherent or explicitly introduced, has become an important issue in the verification of programs. In this paper we study a formalism which allows reasoning about programs which can act probabilistically. To describe probabilistic programs, a basic programming language with an oper ..."
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Cited by 14 (3 self)
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Probability, be it inherent or explicitly introduced, has become an important issue in the verification of programs. In this paper we study a formalism which allows reasoning about programs which can act probabilistically. To describe probabilistic programs, a basic programming language with an operator for probabilistic choice is introduced and a denotational semantics is given for this language. To specify properties of probabilistic programs, standard first order logic predicates are insufficient, so a notion of probabilistic predicates is introduced. A Hoarestyle proof system to check properties of probabilistic programs is given. The proof system for a sublanguage is shown to be sound and complete; the properties that can be derived are exactly the valid properties. Finally some typical examples illustrate the use of the probabilistic predicates and the proof system.
Quantitative Observables and Averages in Probabilistic Constraint Programming
 New Trends in Constraints, number 1865 in Lecture Notes in Computer Science
, 1999
"... We investigate notions of observable behaviour of programs which include quantitative aspects of computation along with the most commonly assumed qualitative ones. We model these notions by means of a transition system where transitions occur with a given probability and an associated `cost' express ..."
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Cited by 12 (7 self)
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We investigate notions of observable behaviour of programs which include quantitative aspects of computation along with the most commonly assumed qualitative ones. We model these notions by means of a transition system where transitions occur with a given probability and an associated `cost' expressing some complexity measure (e.g. running time or, in general, resources consumption).