K. G. Larsen, P. Petterson, and Y. Wang. Compositional and symbolic modelchecking of real-time systems. In Proceedings of the 16th Real-Time Systems Symposium, pages 76--87. IEEE Computer Society Press, 1995.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....believe that, in the context of iterative composition, Kronos is not able to detect dead transitions whose triggering conditions depend on global variable values. Moreover, Kronos detects dead transitions by generating a Cartesian product of automata, which can be very space inefficient. UPPAAL [31], 30] 7] is a widely used verification tool for real time systems with a graphical interface, simulation, quotient construction, minimizations, trivial equation elimination, and equivalence reduction implemented [31] Memory space explosion was tactically handled by compact data structures [30] ....

....a Cartesian product of automata, which can be very space inefficient. UPPAAL [31] 30] 7] is a widely used verification tool for real time systems with a graphical interface, simulation, quotient construction, minimizations, trivial equation elimination, and equivalence reduction implemented [31]. Memory space explosion was tactically handled by compact data structures [30] and optimized constraint manipulations [7] In Section 7.4, we discuss how to reduce state graph sizes through bypassing internal transitions. Similar concepts may be dated back to the internal action of process ....

K.G. Larsen, P. Petterson, and W. Yi, "Compositional and Symbolic Model-Checking of Real-Time Systems," Proc. 16th IEEE Real-Time Systems Symp., pp. 76-87, Dec. 1995.

.... # time abstracting bisimulation: equivalence classes are induced by abstracting away from the exact amount of time elapsed [24, 19] # minimization techniques for minimal state graph generation [4, 7] # quotient construction by moving parts of a parallel system into the formula to be verified [20], # equivalence reduction of identifiers: that is, two identifiers that are semantically equivalent are collapsed [20] # partial order reductions: equivalent interleavings of concurrent events are grouped into traces and it suffices to explore just one representative interleaving from each ....

.... [24, 19] # minimization techniques for minimal state graph generation [4, 7] # quotient construction by moving parts of a parallel system into the formula to be verified [20] # equivalence reduction of identifiers: that is, two identifiers that are semantically equivalent are collapsed [20], # partial order reductions: equivalent interleavings of concurrent events are grouped into traces and it suffices to explore just one representative interleaving from each trace for verifying temporal logic properties [23] # partial order reductions in symbolic state space exploration: an ....

K. G. Larsen, P. Petterson, and W. Yi. Compositional and symbolic model-checking of real-time systems. In Proc. 16th IEEE Real-Time Systems Symposium, pages 76--87, December 1995.

.... for representing and manipulating logics (e.g. di erence bound matrices [9] di erence decision diagrams [22] clock di erence diagrams [15] and quanti er elimination [13] Techniques for formal analysis (e.g. partial order techniques [10, 19] and compositional and on the y techniques [16, 5]) Tools for automatic veri cation (e.g. Kronos [29] Uppaal [18] RED [27] and Tempo [25] The core operation in reachability analysis of real time system is the computation of the least xpoint of a functional of the form X [ 0 f(X) where f is a function that given a set of states, ....

K.G. Larsen, P. Pettersson, and W. Yi. Compositional and symbolic modelchecking of real-time systems. In Proc. 16th Annual Real-time Systems Symposium, pages 7689. IEEE Computer Society Press, 1995.

....discrete continuous systems. These models are in essence purely semantical models. Various classes of automata have been identi ed that allow for automated answering of questions about their behaviour. The results thereof have led to the development of various tools (see e.g. HyTech [14] Uppaal [20, 21]) that eciently can check properties of a system. Process algebras have been introduced to study the theory and the fundamental concepts of processes, non determinism, concurrency and behavioural equivalences. Moreover, process algebras are widely used for studying and performing algebraic veri ....

K. Larsen, P. Pettersson, and W. Yi. Compositional and symbolic model-checking of real-time systems. In Proceedings of the 16th IEEE Real-Time Systems Symposium, 1995.

....encoding of asynchronous system models, such as distributed embedded systems. For the sake of completeness, we brie y mention some other BDD based techniques exploiting the component based structure of many digital systems. They include partial model checking [3] compositional model checking [19], partial order reduction [2] and conjunctive decompositions [21] Finally, also note that approaches to symbolic veri cation have been developed, which do not rely on decision diagrams but instead on arithmetic or algebra [1, 6, 26] 7 Conclusions and Future Work We presented a novel ....

K. Larsen, P. Pettersson, and W. Yi. Compositional and symbolic model-checking of real-time systems. In RTSS '95, pp. 76-89. Computer Society Press, 1995.

.... World Wide Web and anonymous FTP: http: www.brics.dk ftp: ftp.brics.dk This document in subdirectory RS 96 60 ABSTRACT UPPAAL is a tool suite for automatic verification of safety and bounded liveness properties of real time systems modeled as networks of timed automata [12, 9, 4], developed during the past two years. In this paper, we summarize the main features of UPPAAL in particular its various extensions developed in 1995 as well as applications to various case studies, review and provide pointers to the theoretical foundation. 1 Introduction UPPAAL is a tool ....

....as applications to various case studies, review and provide pointers to the theoretical foundation. 1 Introduction UPPAAL is a tool suite for automatic verification of safety and bounded liveness properties of real time systems modeled as networks of timed automata extended with data variables [12, 9, 4], developed during the past two years. In this paper, we summarize the features of UPPAAL in particular the various extensions developed in 1995 as well as applications to various case studies, review and provide pointers to the theoretical foundation. In developing an automatic verification ....

[Article contains additional citation context not shown here]

Kim G. Larsen, Paul Pettersson, and Wang Yi. Compositional and Symbolic ModelChecking of Real-Time Systems. In Proc. of the 16th IEEE Real-Time Systems Symposium, pages 76--87, December 1995.

....costly operation on DBM s with time complexity O(n ) n being the number of clocks) DBM s obviously consume space of order O(n ) Alternatively, one may represent a clock constraint system by choosing a minimal subset from the constraints of the DBM in canonical form. This minimal form [LPW95] is preferable when adding a symbolic state to the main global datastructure Passed as in practice the space requirement is only linear in the number of clocks. Considering once again the reachability algorithm in Figure 1, we see that a symbolic state (l; D) from the waiting list Wait is freed ....

Kim G. Larsen, Paul Pettersson and Wang Yi. Compositional and Symbolic ModelChecking of Real-Time Systems. In Proceedings of the 16th IEEE Real-Time Systems Symposium, Pisa, Italy, 5-7 December, 1995.

....of timed automata, with the di#erent components of the plant (e.g. batches, recipes, casting machine, cranes, etc. constituting the individual timed automata. The scheduling problem is formulated as a time bounded reachability question allowing us to apply the real time modelchecking tool Uppaal [106, 109] to derive a schedule. An overview of the methodology is shown in Figure 8.1. Uppaal o#ers a trace with actions of the model and timing information of the actions. The remaining e#ort required in transforming such a model trace into an executable control program depends heavily on the accuracy of ....

....steel qualities is the main part of the problem. It can be solved in a number of ways. Here we chose x =5, y =3 P: Q: x =1, j 50 y: 0, j: j 2 x: 0, y: 0 a i 10 i: i 1 Figure 8.3: A Network of Timed Automata. to model the plant using timed automata [13] and use the verification tool Uppaal [106, 109] to solve the scheduling problem . The use of timed automata for modeling the plant enables the scheduling problem to be reformulated as a reachability problem which can be solved by Uppaal. A discussion of this approach to scheduling can be found in [64] The modeling language in Uppaal is ....

[Article contains additional citation context not shown here]

K. G. Larsen, P. Pettersson, and W. Yi. Compositional and Symbolic ModelChecking of Real-Time Systems. In Proc. of the 16th IEEE Real-Time Systems Symposium, pages 76--87. IEEE Computer Society Press, Dec. 1995.

....time of our tool seems to be polynomial using a good variable ordering (third row) A BDD based version of Kronos is able to verify 14 processes as reported in [BMPY97] which also looks like exponential growth of computation time. Better results (than in the table) for Uppaal are reported in [LPY95] but still exponential (20 seconds for 6 processes, 150 seconds for 7 processes) Wang reports verification of 17 processes in 15,330 seconds on a Pentium II with 366 MHz and 256 MB memory [Wan00] Figure 5 compares Rabbit with Wang s tool, which uses a BDD like data structure called DDD. No. ....

Kim G. Larsen, Paul Pettersson, and Wang Yi. Compositional and symbolic model-checking of real-time systems. In Proceedings of the 16th IEEE Real-Time Systems Symposium (RTSS'95), pages 76--87, 1995.

....the disjunction of the constraints j where j i. For constraint domains that do not satisfy the independence property 1 , checking for global entailment is usually more expensive than checking for local entailment. Many model checkers use local entailment for their xpont test (e.g. UPPAAL [LPY95] uses identity; the model checker for in nite state systems described in [DP99] uses local entailment) Remark 1. A symbolic forward analysis for an in nite state system S with respect to the initial constraint 0 is a symbolic forward analysis of the constraint transformer monoid generated ....

K.G. Larsen, P. Pettersson, and W. Yi. Compositional and symbolic model checking of real-time systems. In Proceedings of the 16th Annual Real-time Systems Symposium, pages 76-87. IEEE Computer Society Press, 1995. 16

....encoding of asynchronous system models, such as distributed embedded systems. For the sake of completeness, we brie y mention some other BDD based techniques exploiting the component based structure of many digital systems. They include partial model checking [3] compositional model checking [19], partial order reduction [2] and conjunctive decompositions [21] Finally, also note that approaches to symbolic veri cation have been developed, which do not rely on decision diagrams but instead on arithmetic or algebra [1, 6, 26] 7 Conclusions and Future Work We presented a novel approach ....

K. Larsen, P. Pettersson, and W. Yi. Compositional and symbolic model-checking of real-time systems. In RTSS '95, pp. 76-89. Computer Society Press, 1995.

....model, the complexity of which can be quite high. These models, as well as the veri cation algorithms are considerably more complex than in the discrete time case. Initial tools were unable to handle models with more than hundreds or thousands of states. Current tools are signi cantly more ecient [11,15,18], but verifying timed automata is still much more expensive than the veri cation of discrete time models. However, discrete time models have one major disadvantage over continuous time models: their limitation in expressing the semantics of event sequences that happen in short periods of time. ....

.... Veri cation is then performed on a nite state quotient 3 Campos model, such as the region graph [1] or the zone automaton [13] However, the expressive accuracy comes with a signi cant increase in complexity, and a signi cant e ort in the development of continuous time model checkers [18,15] has been devoted to dealing with the state explosion problem. The expressiveness and eciency trade o s between discrete and continuous time raise the question when a discrete time approximation is sucient to model all continuous time behaviors of a system. This problem is analyzed, e.g. in ....

K. G. Larsen, P. Pettersson, and W. Yi. Compositional and symbolic modelchecking of real-time systems. In Proc. 16th IEEE Real-Time Systems Symp., pages 76-87, Pisa, Italy, Dec. 1995. IEEE Press.

....encoding of asynchronous system models, such as distributed embedded systems. For the sake of completeness, we briefly mention some other BDD based techniques exploiting the component based structure of many digital systems. They include partial model checking [3] compositional model checking [19], partial order reduction [2] and conjunctive decompositions [21] Finally, also note that approaches to symbolic verification have been developed, which do not rely on decision diagrams but instead on arithmetic or algebra [1, 6, 26] 7 Conclusions and Future Work We presented a novel ....

K. Larsen, P. Pettersson, and W. Yi. Compositional and symbolic model-checking of real-time systems. In RTSS '95, pp. 76--89. Computer Society Press, 1995.

....for symbolic forward analysis seem interesting for three reasons. First, since they apply to concrete examples such as practical mutual exclusion protocols, they may shed a new light on the practical success of symbolic model checking for infinite state systems (see e.g. BGP97,DP99,DT98,LPY95] Second, for a concrete verification problem in a practical setting, the model to be checked can possibly be adapted to meet the sufficient termination conditions (e.g. by adding semantically redundant initializations of variables or hiding not used variables) we give such examples in the ....

....property of o minimal systems is that the action in the guarded command does not depend on the current values of variables (these values are relevant only for the guard of the command) 2. 2 Parallel Composition In this section we consider asynchronous parallel composition of hybrid systems [LPY95] Parallel composition of integer valued systems is considered in Section 5. We assume that the component programs do not share variables (except for the synchronizing labels) For the purpose of parallel composition, we assign to each guarded command a synchronizing label. Thus with each ....

K.G. Larsen, P. Pettersson, and W. Yi. Compositional and symbolic model checking of real-time systems. In Proceedings of the 16th Annual Real-time Systems Symposium, pages 76--87. IEEE Computer Society Press, 1995.

No context found.

K. G. Larsen, P. Petterson, and Y. Wang. Compositional and symbolic model-checking of real-time systems. In Proceedings of the 16th Real-Time Systems Symposium, pages 76--87. IEEE Computer Society Press, 1995.

....speci ed in the automaton. Parallel Composition. To handle concurrency and synchronization, the parallel composition of extended timed automata may be de ned as the product of the automata in the same way as for ordinary timed automata using the notion of synchronization function (e.g. see [16]) Note that the parallel composition here is only an operator to construct models of systems based on their components. It has nothing to do with multi processor scheduling. A product automaton may be scheduled to run on a one or multi processor system. Note that M is a partial function ....

K. G. Larsen, P. P., and W. Yi. Compositional and symbolic model-checking of real-time systems. In Proceedings of 16th IEEE Real-Time Systems Symposium, December 5-7, 1995 Pisa, Italy, pages 76-89. IEEE Computer Society Press, 1995.

....to be propogated through the graph. These constraints can then be combined by the local information in a node, and can be used to simplify the nodes. They can also be combined in order to produce new constraints to be propagated in the CDD. This ideas are in fact extensions of the idea used in [LPW95] und [KLLPW97] 12 The most simple rule is that any interval in a node can propagate the constraint imposed by itself on the type of the node either up or downwards the CDD. Further any constraint which arrives at a node can be forwarded to the other nodes up and downwards in the graph. These ....

Kim G. Larsen, Paul Pettersson and Wang Yi. Compositional and Symbolic Model-Checking of Real-Time Systems. In Proceedings of the 16th IEEE Real-Time Systems Symposium, Pisa, Italy, 5-7 December, 1995.

....of the timed protocol and finally we consider the verification of timing properties. 3.1. The UPPAAL tool. UPPAAL is a tool suite for automatic verification of safety and bounded liveness properties of real time systems modeled as networks of timed automata extended with data variables [YPD94, LPY95a, BLL 95] developed during the past two years. In this section, we summarize the main features of UPPAAL, applications to various case studies and provide pointer to the theoretical foundation. UPPAAL consists of a graphical user interface based on Autograph, that allows system descriptions ....

.... UPPAAL consists of a graphical user interface based on Autograph, that allows system descriptions to be defined graphically and a model checker that combines on the fly verification with a symbolic technique reducing the verification problem to that of solving simple constraint systems [YPD94, LPY95a] The current version of UPPAAL is able to check for invariant and reachability properties, in particular whether certain combinations of control nodes of timed automata and constraints on variables are reachable from an initial configuration. Bounded liveness properties can be checked by ....

[Article contains additional citation context not shown here]

Kim G. Larsen, Paul Pettersson, and Wang Yi, Compositional and Symbolic ModelChecking of Real-Time Systems, Proc. of the 16th IEEE Real-Time Systems Symposium, December 1995, pp. 76--87.

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K. G. Larsen, P. Petterson, and Y. Wang. Compositional and symbolic modelchecking of real-time systems. In Proceedings of the 16th Real-Time Systems Symposium, pages 76--87. IEEE Computer Society Press, 1995.

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K. G. Larsen, P. Pettersson, and W. Yi. Compositional and Symbolic Model-Checking of Real-Time Systems. In Proc. of the 16th IEEE Real-Time Systems Symposium, pages 7687. IEEE Computer Society Press, December 1995.

No context found.

K. G. Larsen, P. Pettersson and W. Yi. Compositional and Symbolic Model-Checking of Real-Time Systems. Proceedings of the 16th IEEE Real-Time Systems Symposium, Pisa, Italy, 5-7 December, 1995.

No context found.

K. G. Larsen, P. Petterson, and W. Yi. Compositional and symbolic modelchecking of real-time systems. In Proceedings of the 16th IEEE Real-Time Systems Symposium, pages 76--87, Pisa, Italy, December 1995.

No context found.

K. G. Larsen, P. Pettersson and W. Yi. Compositional and Symbolic Model-Checking of Real-Time Systems. Proceedings of the 16th IEEE Real-Time Systems Symposium, Pisa, Italy, 5-7 December, 1995.

No context found.

K. G. Larsen, P. Petterson, and Wang Yi. Compositional and symbolic model-checking of real-time systems. In Proceedings of the 16th IEEE Real-Time Systems Symposium, pages 76--87, Pisa, Italy, Dec. 1995.

No context found.

K. G. Larsen, P. Pettersson, and W. Yi. Compositional and symbolic modelchecking of real-time systems. In A. Burns, Y.-H. Lee, and K. Ramamritham, editors, Proceedings of the 16th IEEE Real-Time Systems Symposium (RTSS'95), pages 76--87. IEEE Computer Society Press, 1995.

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