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14
Performance analysis of probabilistic timed automata using digital clocks
 Proc. Formal Modeling and Analysis of Timed Systems (FORMATS’03), volume 2791 of LNCS
, 2003
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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 77 (27 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".
Verifying quantitative properties of continuous probabilistic timed automata
, 2000
"... Abstract. We consider the problem of automatically verifying realtime systems with continuously distributed random delays. We generalise probabilistic timed automata introduced in [19], an extension of the timed automata model of [4], with clock resets made according to continuous probability distri ..."
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Cited by 46 (10 self)
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Abstract. We consider the problem of automatically verifying realtime systems with continuously distributed random delays. We generalise probabilistic timed automata introduced in [19], an extension of the timed automata model of [4], with clock resets made according to continuous probability distributions. Thus, our model exhibits nondeterministic and probabilistic choice, the latter being made according to both discrete and continuous probability distributions. To facilitate algorithmic verification, we modify the standard region graph construction by subdividing the unit intervals in order to approximate the probability to within an interval. We then develop a model checking method for continuous probabilistic timed automata, taking as our specification language Probabilistic Timed Computation Tree Logic (PTCTL). Our method improves on the previously known techniques in that it allows the verification of quantitative probability bounds, as opposed to qualitative properties which can only refer to bounds of probability 0 or 1. 1
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 45 (27 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...
Probabilistic model checking of the IEEE 802.11 wireless local area network protocol
 Proc. 2nd Joint International Workshop on Process Algebra and Probabilistic Methods, Performance Modeling and Verification (PAPM/PROBMIV’02), volume 2399 of LNCS
, 2002
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Automatic Verification of the IEEE1394 Root Contention Protocol with KRONOS and PRISM
 SOFTWARE TOOLS FOR TECHNOLOGY TRANSFER
"... We report on the automatic verification of timed probabilistic properties of the IEEE 1394 root contention protocol combining two existing tools: the realtime modelchecker Kronos and the probabilistic modelchecker Prism. The system is modelled as a probabilistic timed automaton. We first use Kro ..."
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Cited by 28 (10 self)
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We report on the automatic verification of timed probabilistic properties of the IEEE 1394 root contention protocol combining two existing tools: the realtime modelchecker Kronos and the probabilistic modelchecker Prism. The system is modelled as a probabilistic timed automaton. We first use Kronos to perform a symbolic forward reachability analysis to generate the set of states that are reachable with nonzero probability from the initial state, and before the deadline expires. We then encode this information as a Markov decision process to be analyzed with Prism. We apply this technique to compute the minimal probability of a leader being elected before a deadline, for different deadlines, and study how this minimal probability is influenced by using a biased coin and considering different wire lengths.
Symbolic Computation of Maximal Probabilistic Reachability
 In Proc. CONCUR'01, volume 2154 of LNCS
, 2001
"... We study the maximal reachability probability problem for infinitestate systems featuring both nondeterministic and probabilistic choice. The problem involves the computation of the maximal probability of reaching a given set of states, and underlies decision procedures for the automatic verificati ..."
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Cited by 12 (8 self)
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We study the maximal reachability probability problem for infinitestate systems featuring both nondeterministic and probabilistic choice. The problem involves the computation of the maximal probability of reaching a given set of states, and underlies decision procedures for the automatic verification of probabilistic systems. We extend the framework of symbolic transition systems, which equips an infinitestate system with an algebra of symbolic operators on its state space, with a symbolic encoding of probabilistic transitions to obtain a model for an infinitestate probabilistic system called a symbolic probabilistic system.
Fun with FireWire: a comparative study of formal verification methods applied to the IEEE 1394 Root Contention Protocol
"... The IEEE 1394 Root Contention Protocol is an industrial leader election algorithm for two processes in which probability, real{time and parameters play an important role. This protocol has been analysed in various case studies, using a variety of veri cation and analysis methods. In this paper, we ..."
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Cited by 11 (0 self)
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The IEEE 1394 Root Contention Protocol is an industrial leader election algorithm for two processes in which probability, real{time and parameters play an important role. This protocol has been analysed in various case studies, using a variety of veri cation and analysis methods. In this paper, we survey and compare several of these case studies.
PCTL model checking of symbolic probabilistic systems
, 2003
"... Probabilistic model checking is a method for automatically verifying that a probabilistic system satisfies a property with a given likelihood, with the probabilistic temporal logic Pctl being a common choice for the property specification language. In this paper, we explore methods for model che ..."
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Cited by 2 (0 self)
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Probabilistic model checking is a method for automatically verifying that a probabilistic system satisfies a property with a given likelihood, with the probabilistic temporal logic Pctl being a common choice for the property specification language. In this paper, we explore methods for model checking Pctl properties of infinitestate systems in which probabilistic and nondeterministic behaviour coexist. Building on previous work on computing the maximum probability with which a state set is reached in such systems, we utilize symbolic operations on the state sets to generate a finitestate version of the system on which the Pctl model checking problem can be answered. As in the nonprobabilistic case, our model checking algorithm is semidecidable for infinitestate systems. We illustrate our technique using the formalism of probabilistic timed automata, for which previous Pctl model checking techniques were based on an unnecessarily ne subdivisions of the state space.
J.Sproston. Verifying soft deadlines with probabilistic timed automata
 In Proc. of the Workshop on Advances in Verification (WAVe
, 2000
"... Abstract. This paper describes work in progess performed as part of an ongoing project aimed at the development of theoretical foundations and model checking algorithms for the verification of soft deadlines in timed systems, that is, properties such as “there is a 90 % chance that the message will ..."
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Cited by 2 (0 self)
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Abstract. This paper describes work in progess performed as part of an ongoing project aimed at the development of theoretical foundations and model checking algorithms for the verification of soft deadlines in timed systems, that is, properties such as “there is a 90 % chance that the message will be delivered within 5 time units”. The research is focussed on the probabilistic timed automata model [11], an extension of timed automata [3], and includes: model checking of discreteprobabilistic automata based on the region graph construction [11]; symbolic methods based on forwards and backwards reachability [10,13]; and the continuous probabilistic timed automata [12]. 1