V. Gupta, T. Henzinger, and R. Jagadeesan. Robust timed automata. In O. Maler, editor, HART 97: Hybrid and RealTime Systems, LNCS 1201, pages 331--345. 1997.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....NWO, the Dutch Ministry of Economic Affairs, the Technology Foundation STW and the Netherlands Organisation for Applied Scientific Research TNO. However, a model is generally only an approximation of its realization with respect to time (or vise versa) For example, it has been argued in [12] that a real time formal model M often over specifies its corresponding physical realizations. In model M , the issuing time of an event p is usually specified as some time instant t M . However, it cannot be guaranteed that the issuing time t M of p in M is identical to its counterpart t R in R ....

....Prop is formally defined as follows. For #,# # S Prop , d sup (#,# # ) d(I,I # ) if # s # # ; wise where d(I,I # ) which is defined in Section 2.1, denotes the distance between two time interval sequences. Gupta et al. proposed several metrics over finite timed state sequences in [12]. We only adopt d sup (similar to the metric dma in [12] as a measure over S Prop including both infinite and finite timed state sequences. Definition 6. Fo r # = #, I) and # #0 we define an # close set T S Prop d sup (#,# # ) # . Set T # includes all timed state sequences whose ....

[Article contains additional citation context not shown here]

V. Gupta, T.A. Henzinger, and R. Jagadeesan. Robust timed automata. In O. Maler, editor, Hybrid and Real-Time Systems, Proceedings of International Workshop HART'97, pages 331--345, Grenoble, France, 1997. Springer Verlag, LNCS 1201.

....of representing the state space. Due to the regular and intuitive structure of regions they have proven very useful as a basis for a number of fundamental results concerning timed automata. In particular a number of decidability results have been proven based on (algorithms using) regions, e.g. [12, 13, 49, 103, 68, 84, 40, 28, 101]. Many of these prove decidability by explicitly stating an algorithm using the operations defined on regions, and have since been extended to more e#cient ways of representing sets of states. 2.2 Timed Automata Extended with Linear Cost Timed verification tools like Uppaal [109] and Kronos [41] ....

V. Gupta, T. A. Henzinger, and R. Jagadeesan. Robust timed automata. In O. Maler, editor, Hybrid and Real-Time Systems, Lecture Notes in Computer Science, pages 331--345. Springer--Verlag, March 1997.

....within of . While a variety of mathematical formulations of these concepts have been proposed for hybrid and switched dynamical systems (stability is surveyed in this issue in [44] there has been little work to date on integrating these concerns within a framework for formal methods [25] [47]. There is perhaps good reason for this. Coming as they do from computer science, formal methods traditionally lie in the realm of discrete mathematics, while these notions from control theory lie squarely in the realm of continuous mathematics. Well before hybrid systems, the classic systems ....

....FOR HYBRID SYSTEMS 1001 , suppose the evolution relations satisfy for each . This says that if is an integral curve of witnessing an evolution in a variant , then there is an integral curve of starting from , witnessing in the nominal system , such that lies within a tube around (see [25] and [47], which consider tubes around time sequences) Translating this relational inclusion into modal formulas, we have and hence where So for the verification of a robust safety property, it would suffice to prove , since this entails for any such variant . One can also work with the finitary ....

V. Gupta, T. A. Henzinger, and R. Jagadeesan, "Robust timed automata, " in Hybrid and Real-Time Systems: International Workshop HART'97, O. Maler, Ed: Springer-Verlag, 1997, pp. 331--345. LNCS 1201.

....undecidability may still prevail if the automaton A is of the form A = B or A = B sup , is a viable one. Finally, it should be noted that a fundamentally different approach to modeling noisy behaviour of timed or hybrid automata has been proposed by Gupta, Henzinger, and Jagadeesan [GHJ97]. In that line of work, the idealized behavioural model of timed automata is essentially kept and only filtered a posteriori by removing accepted and adding rejected trajectories that are isolated with respect to some topology on trajectories. However, it seems that this model has less favorable ....

Vineet Gupta, Thomas A. Henzinger, and Radha Jagadeesan. Robust timed automata. In Oded Maler, editor, Proceedings of the First International Workshop on Hybrid and Real-Time Systems (HART 97), volume 1201 of Lecture Notes in Computer Science, pages 331--345. Springer-Verlag, 1997.

....within # of P . While a variety of mathematical formulations of these concepts have been proposed for hybrid and switched dynamical systems (stability is surveyed in this issue in [44] there has been little work to date on integrating these concerns within a framework for formal methods [25] [47]. There is perhaps good reason for this. Coming as they do from computer science, formal methods traditionally lie in the realm of discrete mathematics, while these notions from control theory lie squarely in the realm of continuous mathematics. Well before hybrid systems, the classic systems ....

....integral curve of # # q witnessing an evolution x e # q # y in a variant H # , then DAVOREN AND NERODE: LOGICS FOR HYBRID SYSTEMS 1017 there is an integral curve # of # q starting from x, witnessing x eq # y in the nominal system H , such that # # lies within a # tube around # (c.f. 25] [47], which consider # tubes around time sequences) Translating this relational inclusion into modal formulas, we have: e] #]Z # [e # ]Z and hence [h # ]Z # [h # ]Z where [h # ]Z def = #W. e] #]Z # [e] #] r]W [h # ]Z def = #W. e # ]Z # [e # ] r]W So for the verification of a ....

V. Gupta, T.A. Henzinger, and R. Jagadeesan, "Robust timed automata," In Maler [5], pp. 331--345.

....from x, the picture really is that of an ffl tube: if dX (x; x 0 ) ffi then the trajectory f(x 0 ) lies inside an ffl tube around the trajectory f(x) as illustrated in Figure 4. The idea is certainly reminiscent of the tube neighborhoods in the work of Gupta, Henzinger and Jagadeesan [17] on robust timed automata; the interest in that paper is on metrics on trajectories 2 ( Phi Theta R 0 ) where Phi is a finite alphabet of event names. When X is a compact metric space, OE : X Theta R X is a continuous semiflow, and T R is compact, the restricted orbit ....

V. Gupta, T. A. Henzinger and R. Jagadeesan, "Robust Timed Automata", in O. Maler (ed.), Hybrid and Real-Time Systems: International Workshop HART'97, March 1997, Lecture Notes in Computer Science 1201 (Springer-Verlag, Berlin, 1997); 331-345.

....These clocks share the same unit of time but can be reset independently when a transition is traversed. A transition is enabled provided certain conditions on the values of the clocks are met. This initial model has been extended in various directions to accomodate precision of computation [15], transitions (also called silent transitions, moves or silent moves) 11, 14, 18] convergent sequences of time [12] hybrid models [16] etc. The original model of timed automata is speci ed in terms of conditions involving intervals only: e.g. a transition is enabled when 1 x 2 and ....

V. Gupta, T. A. Henzinger, and R. Jagadeesan. Robust timed automata. In Proceedings of HART'97, number 1201 in Lecture Notes in Computer Science, pages 331-345. Springer Verlag, 1997.

....work. To the best of our knowledge, dynamics of hybrid automata under noise has so far only been analyzed for the subclass of timed automata, where two fundamentally different models of the robust , noise resistant behaviour of timed automata have been proposed by Gupta, Henzinger, and Jagadeesan [2] and by Puri [6] both reports do, however, sketch generalizations to hybrid automata) While in the former line of work, the idealized behavioural model of timed automata is essentially kept and only filtered a posteriori by removing accepted and adding rejected trajectories that are isolated ....

V. Gupta, T. A. Henzinger, and R. Jagadeesan. Robust timed automata. In O. Maler, editor, Proceedings of the First International Workshop on Hybrid and Real-Time Systems (HART 97), volume 1201 of Lecture Notes in Computer Science, pages 331--345. Springer-Verlag, 1997.

....Response Automata, a special case of TIOA s which appears to be su#ciently expressive for most applications but can nevertheless be fully tested by considering grid subautomata with time steps of size 1. Another possibility in this direction is to obtain more robust versions (in the sense of [GHJ97] of our timed I O automata. Basically, a TIOA is robust if, whenever it accepts a trace, it accepts a neighboring trace as well, under some reasonable topology on the set of traces. We hope that a more robust model will yield significantly smaller test sets. An alternative line of attack is to ....

V. Gupta, T.A. Henzinger, and R. Jagadeesan. Robust timed automata. In O. Maler, editor, Proceedings International Workshop HART'97, volume 1201 of Lecture Notes in Computer Science, pages 331--345. Springer-Verlag, 1997.

....These clocks share the same unit of time but can be reset independently when a transition is traversed. A transition is enabled provided certain conditions on the values of the clocks are met. This initial model has been extended in various directions to accomodate precision of computation [14], ffl transitions (also called silent transitions, ffl moves or silent moves) 6, 9] convergent sequences of time [7] hybrid models, 15] etc, The original model of timed automata is specified in terms of conditions envolving intervals only: e.g. a transition is enabled when 1 x 2 ....

V. Gupta, T. A. Henzinger, and R. Jagadeesan. Robust timed automata. In Proceedings of HART'97, number 1201 in Lecture Notes in Computer Science, pages 331--345. Springer Verlag, 1997.

....Instead of taking the worst case grid size right away, one might start off with a coarse grid to obtain a small, incomplete set of useful tests. If desired, the grid can be subsequently refined, thus approximating the required grid size. Our timed I O automata are not robust in the sense of [GHJ97] it is not the case that if a TIOA accepts a trace it accepts a neighboring trace as well, under some reasonable topology on the set of traces. The authors of [GHJ97] argue that non robust automata are not physically realizable: one cannot build a machine that performs an output action exactly ....

....can be subsequently refined, thus approximating the required grid size. Our timed I O automata are not robust in the sense of [GHJ97] it is not the case that if a TIOA accepts a trace it accepts a neighboring trace as well, under some reasonable topology on the set of traces. The authors of [GHJ97] argue that non robust automata are not physically realizable: one cannot build a machine that performs an output action exactly at time 7. Even though this is of course right, we feel that our TIOA s do provide a reasonable abstraction of many real world systems. What needs to be added to our ....

V. Gupta, T.A. Henzinger, and R. Jagadeesan. Robust timed automata. In O. Maler, editor, Proceedings International Workshop HART'97, volume 1201 of Lecture Notes in Computer Science, pages 331--345. Springer-Verlag, 1997.

No context found.

V. Gupta, T. A. Henzinger, and R. Jagadeesan. Robust timed automata. In O. Maler, editor, Hybrid and RealTime Systems, volume 1201 of Lecture Notes In Computer Science, pages 331--345. Springer Verlag, March 1997.

....that are close does not yield a transitive relation. This leads them to propose that the correct formulation of the nearness notion is via a metric. Similar reasons motivate the study of Lincoln, Mitchell, Mitchell and Scedrov [LMMS98] our earlier studies of metrics for real time systems [GHJ97] and our study of metrics for labelled Markov processes and strong bisimulation [DGJP99, DGJP00] and the study of the ne structure of these metrics by van Breugel and Worrell [vBW01b, vBW01a] In contrast to these investigations, this paper will be carried out in the context of internal ....

V. Gupta, T. A. Henzinger, and R. Jagadeesan. Robust timed automata. In Oded Maler, editor, Hybrid and Real-Time Systems, volume 1201 of Lecture Notes In Computer Science, pages 331-345. Springer Verlag, March 1997.

....of active research at the moment. The veri cation community has been active in developing model checking tools for probabilistic systems, for example [BLL 96, BdA95, BCHG 97, CY95, HK97] Approximation techniques in the spirit of those of this paper have been explored for hybrid systems [GHJ97] Since the rst appearance of the present work [DGJP99] we have developed a theory of approximation for labelled Markov processes [DGJP00, DGJP03] Before we discuss work speci cally related to metrics for probabilistic processes it is worth discussing work from the probability theory ....

V. Gupta, T. A. Henzinger, and R. Jagadeesan. Robust timed automata. In Oded Maler, editor, Hybrid and Real-Time Systems, volume 1201 of Lecture Notes In Computer Science, pages 331-345. Springer Verlag, March 1997.

....of active research at the moment. The veri cation community has been active in developing model checking tools for probabilistic systems, for example [BLL 96, BdA95, BCHG 97, CY95, HK97] Approximation techniques in the spirit of those of this paper have been explored for hybrid systems [GHJ97] Since the rst 25 appearance of the present work [DGJP99] we have developed a theory of approximation for labelled Markov processes [DGJP00] Before we discuss work speci cally related to metrics for probabilistic processes it is worth discussing work from the probability theory community on ....

V. Gupta, T. A. Henzinger, and R. Jagadeesan. Robust timed automata. In Oded Maler, editor, Hybrid and Real-Time Systems, volume 1201 of Lecture Notes In Computer Science, pages 331-345. Springer Verlag, March 1997.

....be the object of future study. The verification community has been active in developing model checking tools for probabilistic systems, for example [BLL 96, BdA95, BCHG 97, CY95, HK97] Approximation techniques in the spirit of those of this paper have been explored for hybrid systems [GHJ97] In future work, we will explore efficient algorithms and complexity results for our metrics. Our work on the asymptotic metric is closely related to, at least in spirit, the work of Lincoln, Mitchell, Mitchell and Scedrov [LMMS98] in the context of security protocols. Both [LMMS98] and this ....

V. Gupta, T. A. Henzinger, and R. Jagadeesan. Robust timed automata. In Oded Maler, editor, Hybrid and Real-Time Systems, LNCS Vol 1201, pages 331--345. Springer Verlag, March 1997.

....the possible behaviors of a hybrid automaton not as a collection of timed traces but as a collection of timed tubes, which are bundles of almost identical timed traces. The resulting theory of fuzzy hybrid automata does not differ significantly from the results presented in this paper [22]. 2 1.4 Composition For two hybrid automata H 1 and H 2 , we define the timed semantics and the time abstract semantics of the parallel composition H 1 kH 2 . The two hybrid automata H 1 and H 2 interact via joint events: if event a is both an event of H 1 and an event of H 2 , then H 1 and H 2 ....

V. Gupta, T.A. Henzinger, and R. Jagadeesan. Robust timed automata. In O. Maler, editor, HART 97: Hybrid and Real-time Systems, Lecture Notes in Computer Science 1201, pages 331--345. Springer-Verlag, 1997.

No context found.

V. Gupta, T. Henzinger, and R. Jagadeesan. Robust timed automata. In O. Maler, editor, HART 97: Hybrid and RealTime Systems, LNCS 1201, pages 331--345. 1997.

No context found.

V. Gupta, T. A. Henzinger, and R. Jagadeesan. Robust timed automata. In Proceedings of HART 97, volume 1201, pages 331-345. Springer LNCS, 1997.

No context found.

V. Gupta, T. A. Henzinger, and R. Jagadeesan. Robust timed automata. In Proceedings of HART 97, volume 1201, pages 331--345. Springer LNCS, 1997.

No context found.

V. Gupta, T. A. Henzinger, and R. Jagadeesan. Robust timed automata. In Proceedings of HART 97, volume 1201, pages 331-345. Springer LNCS, 1997.

No context found.

Vineet Gupta, Thomas A. Henzinger, and Radha Jagadeesan. Robust timed automata. In O. Maler, editor, Hybrid and Real-Time Systems, Lecture Notes in Computer Science, pages 331-345. Springer Verlag, March 1997.

No context found.

V. Gupta, T. A. Henzinger, and R. Jagadeesan. Robust timed automata. In Proceedings of HART 97, volume 1201, pages 331--345. Springer LNCS, 1997.

No context found.

V. Gupta, T.A. Henzinger, and R. Jagadeesan. Robust timed automata. In O. Maler, editor, Proceedings International Workshop HART'97, volume 1201 of Lecture Notes in Computer Science, pages 331--345. Springer-Verlag, 1997.

No context found.

V. Gupta, T.A. Henzinger, and R. Jagadeesan. Robust timed automata. In Proc. of HART 97, LNCS 1201. Springer-Verlag, 1997.

No context found.

V. Gupta, T. A. Henzinger, and R. Jagadeesan. Robust timed automata. In Proceedings of HART'97, number 1201 in Lecture Notes in Computer Science, pages 331--345. Springer Verlag, 1997.

No context found.

V. Gupta, T. Henzinger, and R. Jagadeesan. Robust timed automata. In O. Maler, editor, HART 97: Hybrid and Real-Time Systems, LNCS 1201, pages 331--345. 1997.

Online articles have much greater impact   More about CiteSeer.IST   Add search form to your site   Submit documents   Feedback  

CiteSeer.IST - Copyright Penn State and NEC