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Reducing Quasi-Equal Clocks in Networks of Timed Automata [chapter]

Christian Herrera, Bernd Westphal, Sergio Feo-Arenis, Marco Muñiz, Andreas Podelski
2012 Lecture Notes in Computer Science  
We introduce the novel notion of quasi-equal clocks and use it to improve the verification time of networks of timed automata.  ...  We propose a transformation that takes a network of timed automata and yields a network of timed automata which has a smaller set of clocks and preserves properties up to those not comparing quasi-equal  ...  Reducing Clocks in Networks of Timed Automata Quasi-Equal Clocks Definition 1 (Quasi-Equal Clocks). Let N be a network with clocks X .  ... 
doi:10.1007/978-3-642-33365-1_12 fatcat:lw4gvyaqw5fi7fskrmbxogvzvq

Quasi-equal Clock Reduction: Eliminating Assumptions on Networks [chapter]

Christian Herrera, Bernd Westphal
2015 Lecture Notes in Computer Science  
Quasi-equal clock reduction for networks of timed automata replaces clocks in equivalence classes by representative clocks.  ...  An existing approach which reduces quasi-equal clocks and does not constrain the support of properties of networks, yields significant reductions of the overall verification time of properties.  ...  The approach in [16] detects quasi-equal clocks in networks of timed automata.  ... 
doi:10.1007/978-3-319-26287-1_11 fatcat:xl2htpbhivaatf3veihlavto44

Quasi-Equal Clock Reduction: More Networks, More Queries [chapter]

Christian Herrera, Bernd Westphal, Andreas Podelski
2014 Lecture Notes in Computer Science  
Quasi-equal clock reduction for networks of timed automata replaces equivalence classes of clocks which are equal except for unstable phases, i.e., points in time where these clocks differ on their valuation  ...  We demonstrate that the cost of verifying non-local properties is much lower in transformed networks than in their original counterparts with quasi-equal clocks.  ...  The query configData := ∀ A.configData = 1 ∧ A.x = 0 ∧ M.y > 0, where A is a sensor and M is the master, x and y are quasi-equal clocks from  ... 
doi:10.1007/978-3-642-54862-8_20 fatcat:lpq2nu7lzjch3pfim4ttsgtbvi

Quasi-dependent variables in hybrid automata

Sergiy Bogomolov, Christian Herrera, Marco Muñiz, Bernd Westphal, Andreas Podelski
2014 Proceedings of the 17th international conference on Hybrid systems: computation and control - HSCC '14  
We approach this problem by providing an effective generalisation of the recently introduced notion of quasi-equal clocks to hybrid systems.  ...  The concept of hybrid automata provides a powerful framework to model and analyze real-world systems.  ...  We thank Goran Frehse for his assistance with SpaceEx during the preparation of our benchmark suite.  ... 
doi:10.1145/2562059.2562142 dblp:conf/hybrid/BogomolovHMWP14 fatcat:zsezgideq5gczhquccbvx34esa

Timed Automata with Disjoint Activity [chapter]

Marco Muñiz, Bernd Westphal, Andreas Podelski
2012 Lecture Notes in Computer Science  
We show that, if the phases of activity of timed automata in a network are disjoint, then location reachability for the network can be decided using a concatenation of timed automata.  ...  This reduces the complexity of verification in Uppaallike tools from quadratic to linear time (in the number of components) while traversing the same reachable state space.  ...  In [8] this notion is generalized to quasi-equal clocks and a more general reduction method for quasi-equal clocks is presented.  ... 
doi:10.1007/978-3-642-33365-1_14 fatcat:kecxgjiwpbfyfcziz6m77wcqdy

Are Timed Automata Bad for a Specification Language? Language Inclusion Checking for Timed Automata [chapter]

Ting Wang, Jun Sun, Yang Liu, Xinyu Wang, Shanping Li
2014 Lecture Notes in Computer Science  
It is known that this problem is undecidable and "this result is an obstacle in using timed automata as a specification language" [2].  ...  Given a timed automaton P modeling an implementation and a timed automaton S as a specification, language inclusion checking is to decide whether the language of P is a subset of that of S.  ...  We skip the details on parallel composition of timed automata and remark our approach in this work applies to networks of timed automata.  ... 
doi:10.1007/978-3-642-54862-8_21 fatcat:fp7csehzoffhzcpxk3he5amuni

On the language inclusion problem for timed automata: closing a decidability gap

J. Ouaknine, J. Worrell
2004 Proceedings of the 19th Annual IEEE Symposium on Logic in Computer Science, 2004.  
The crux of our proof consists in reducing the language inclusion problem to a reachability question on an infinite graph; we then construct a suitable well-quasi-order on the nodes of this graph, which  ...  Moreover, these two cases are essentially the only decidable instances of language inclusion, in terms of restricting the various resources of timed automata.  ...  Timed Automata Let C be a finite set of clocks, denoted x, y, z, etc.  ... 
doi:10.1109/lics.2004.1319600 dblp:conf/lics/OuaknineW04 fatcat:espxw4wma5cbzbntsq72os3324

Analysis of a Clock Synchronization Protocol for Wireless Sensor Networks [chapter]

Faranak Heidarian, Julien Schmaltz, Frits Vaandrager
2009 Lecture Notes in Computer Science  
First, we model the protocol as a network of timed automata and verify various instances using the Uppaal model checker.  ...  One of the greatest challenges in the design is to find suitable mechanisms for clock synchronization. In this paper, we study a proposed clock synchronization protocol for the Chess platform.  ...  In order to reduce the state space, we considered only networks with perfect clocks. However, even with perfect clocks, Uppaal can only handle networks with at most 8 nodes.  ... 
doi:10.1007/978-3-642-05089-3_33 fatcat:ehy625rvc5gahbwbngyxdxfvya

Multi-clock timed networks

P. Aziz Abdulla, J. Deneux, P. Mahata
2004 Proceedings of the 19th Annual IEEE Symposium on Logic in Computer Science, 2004.  
We consider verification of safety properties for parameterized systems of timed processes, so called timed networks.  ...  A timed network consists of a finite state process, called a controller, and an arbitrary set of identical timed processes.  ...  In the literature, there are many applications where a number of timed automata [AD94] run in parallel and where each of the timed automata has more than one clock.  ... 
doi:10.1109/lics.2004.1319629 dblp:conf/lics/AbdullaDM04 fatcat:ejxcrwhbr5hgzmqwhuov6hy32m

Better Quasi-Ordered Transition Systems [article]

Parosh Aziz Abdulla, Aletta Nylen
2004 arXiv   pre-print
We show how to use existential zones in verification of timed Petri nets and present some experimental results.  ...  In this paper, we demonstrate that a refinement of the theory of well quasi-orderings, called the theory of better quasi-orderings, is more appropriate for symbolic model checking, since it allows inventing  ...  Acknowledgments We are grateful to Alberto Marcone and Petr Jančar for many interesting discussions on the theory of better quasi-orderings.  ... 
arXiv:cs/0409052v1 fatcat:pquau6flwjcvletu3ybqrzwx64

On the decidability and complexity of Metric Temporal Logic over finite words

Joel Ouaknine, James Worrell, Prakash Panangaden
2007 Logical Methods in Computer Science  
Over infinite words, we show that model checking the safety fragment of MTL--which includes invariance and time-bounded response properties--is also decidable.  ...  In this paper, we show that the satisfiability problem for MTL over finite timed words is decidable, with non-primitive recursive complexity.  ...  We thank Tom Henzinger for clarifying some of the undecidability results for MTL, and for asking about the relationship between single-clock timed automata and real-time temporal logics.  ... 
doi:10.2168/lmcs-3(1:8)2007 fatcat:kukxxibtibbdvnntn6htmf2mwm

Anonymized Reachability of Hybrid Automata Networks [chapter]

Taylor T. Johnson, Sayan Mitra
2014 Lecture Notes in Computer Science  
Unlike symmetry reduction techniques used in finite state models, the timed transition of a network composed of hybrid automata causes the continuous variables of all the automata to evolve simultaneously  ...  Our experimental results are promising, and generally allow for scaling to networks composed of tens of automata, and in some instances, hundreds (or more) of automata.  ...  Quasi-equal clocks and variables for timed [13] and hybrid (multi-rate) [4] automata networks also allow reductions in state-space explosion, but do not require automata in the network to be identical  ... 
doi:10.1007/978-3-319-10512-3_10 fatcat:a2m36k4orfeedpd23jvbrylxja

Compositional Verification of Parameterised Timed Systems [chapter]

Lăcrămioara Aştefănoaei, Souha Ben Rayana, Saddek Bensalem, Marius Bozga, Jacques Combaz
2015 Lecture Notes in Computer Science  
In this paper we address the problem of uniform verification of parameterised timed systems (PTS): "does a given safety state property hold for a system containing n identical timed components regardless  ...  Additionally, we show how a direct consequence of the modelling choices adopted in our framework leads to an elegant application of the presented method to topologies such as stars and rings.  ...  The small model theorem does not hold in the context of networks of parametric timed automata in its most general case.  ... 
doi:10.1007/978-3-319-17524-9_6 fatcat:ku2al67dtneb7jcxclguk3fofq

Multi-core Reachability for Timed Automata [chapter]

Andreas E. Dalsgaard, Alfons Laarman, Kim G. Larsen, Mads Chr. Olesen, Jaco van de Pol
2012 Lecture Notes in Computer Science  
Acknowledgments We would like to thank the LTSmin and APRON developers for making their excellent code available to others in the research community.  ...  Networks of Extended Timed Automata and Semantics A network of timed automata is a parallel composition of extended timed automata that enables synchronisation over a finite set of channel names Chan.  ...  To describe a lattice transition system in a concise way we will use networks of extended lattice automata (analogously to networks of timed automata as in uppaal [16] ).  ... 
doi:10.1007/978-3-642-33365-1_8 fatcat:qwhq3mr2bzfizm54xhsw7ddd5a

Lumping-Based Equivalences in Markovian Automata and Applications to Product-Form Analyses [chapter]

Andrea Marin, Sabina Rossi
2015 Lecture Notes in Computer Science  
Networks (SAN).  ...  We show the usefulness of this relation by proving that the class of quasi-reversible models is closed under exact equivalence.  ...  Their semantics is given in terms of stochastic automata, an extension of labelled automata with clocks that often are exponentially distributed random variables.  ... 
doi:10.1007/978-3-319-22264-6_11 fatcat:a5tbtnomhjavlgxvxcmclocj3m
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