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Journal Article•DOI•

HYTECH: a model checker for hybrid systems

Thomas A. Henzinger1, Pei-Hsin Ho2, Howard Wong-Toi3•
University of California, Berkeley1, Intel2, Lawrence Berkeley National Laboratory3
01 Dec 1997-International Journal on Software Tools for Technology Transfer (Springer-Verlag)-Vol. 1, Iss: 1, pp 110-122
TL;DR: HyTech is a symbolic model checker for linear hybrid automata, a subclass of hybrids that can be analyzed automatically by computing with polyhedral state sets that combines automaton transitions for capturing discrete change with differential equations for capturing continuous change.
Abstract: A hybrid system consists of a collection of digital programs that interact with each other and with an analog environment. Examples of hybrid systems include medical equipment, manufacturing controllers, automotive controllers, and robots. The formal analysis of the mixed digital-analog nature of these systems requires a model that incorporates the discrete behavior of computer programs with the continuous behavior of environment variables, such as temperature and pressure. Hybrid automata capture both types of behavior by combining finite automata with differential inclusions (i.e. differential inequalities). HyTech is a symbolic model checker for linear hybrid automata, an expressive, yet automatically analyzable, subclass of hybrid automata. A key feature of HyTech is its ability to perform parametric analysis, i.e. to determine the values of design parameters for which a linear hybrid automaton satisfies a temporal requirement.
Citations
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Journal Article•DOI•
What's Decidable about Hybrid Automata?

[...]

Thomas A. Henzinger
01 Aug 1998-Journal of Computer and System Sciences
TL;DR: It is proved that the reachability problem is undecidable for timed automata augmented with a single stopwatch, and an (optimal) PSPACE reachability algorithm is given for the case of initialized rectangular automata.

903 citations

Book Chapter•DOI•
SpaceEx: scalable verification of hybrid systems

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Goran Frehse1, Colas Le Guernic2, Alexandre Donzé1, Scott Cotton1, Rajarshi Ray1, Olivier Lebeltel1, Rodolfo Ripado1, Antoine Girard3, Thao Dang1, Oded Maler1 •
Centre national de la recherche scientifique1, New York University2, University of Grenoble3
14 Jul 2011
TL;DR: A scalable reachability algorithm for hybrid systems with piecewise affine, non-deterministic dynamics that combines polyhedra and support function representations of continuous sets to compute an over-approximation of the reachable states is presented.
Abstract: We present a scalable reachability algorithm for hybrid systems with piecewise affine, non-deterministic dynamics. It combines polyhedra and support function representations of continuous sets to compute an over-approximation of the reachable states. The algorithm improves over previous work by using variable time steps to guarantee a given local error bound. In addition, we propose an improved approximation model, which drastically improves the accuracy of the algorithm. The algorithm is implemented as part of SpaceEx, a new verification platform for hybrid systems, available at spaceex.imag.fr. Experimental results of full fixed-point computations with hybrid systems with more than 100 variables illustrate the scalability of the approach.

901 citations

Journal Article•DOI•
Cyber–Physical Systems: A Perspective at the Centennial

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Kyoung-Dae Kim1, P. R. Kumar1•
Texas A&M University1
03 Apr 2012
TL;DR: This work overviews CPS research from both a historical point of view in terms of technologies developed for early generations of control systems, as well as recent results on CPSs in many relevant research domains such as networked control, hybrid systems, real-time computing,real-time networking, wireless sensor networks, security, and model-driven development.
Abstract: Cyber-physical systems (CPSs) are the next generation of engineered systems in which computing, communication, and control technologies are tightly integrated. Research on CPSs is fundamentally important for engineered systems in many important application domains such as transportation, energy, and medical systems. We overview CPS research from both a historical point of view in terms of technologies developed for early generations of control systems, as well as recent results on CPSs in many relevant research domains such as networked control, hybrid systems, real-time computing, real-time networking, wireless sensor networks, security, and model-driven development. We outline the potential for CPSs in many societally important application domains.

702 citations

Cites background or methods from "HYTECH: a model checker for hybrid ..."

  • ...Some examples are UPPAAL [118], a verification tool for real-time systems based on timed automata, HyTech [99] and PHAVer [119] for LHA, SpaceEx [120] which is based on the LeGuernic-Girard (LGG) algorithm [121] that can efficiently...

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  • ...An example of a hybrid automaton [99]....

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  • ...In [99], an approximation technique, called linear phase portrait approximation, is proposed....

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  • ...An interesting class of hybrid systems, called linear hybrid automata (LHA) [110], [99], are those for which, for each v ∈ V and e ∈ E, (i) the vertex labeling functions flow(v), inv(v), init(v), and edge labeling functions guard(e), reset(e) are finite conjunctions of linear inequalities, and (ii) more importantly, the flow function flow(v) is finite conjunction of linear inequalities over the variables in Ẋ only....

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Book Chapter•DOI•
PHAVer: algorithmic verification of hybrid systems past hytech

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Goran Frehse1•
Carnegie Mellon University1
09 Mar 2005
TL;DR: This work addresses the main problems of HyTech with PHAVer, a new tool for the exact verification of safety properties of hybrid systems with piecewise constant bounds on the derivatives and proposes methods to conservatively limit the number of bits and constraints of polyhedra.
Abstract: In 1995, HyTech broke new ground as a potentially powerful tool for verifying hybrid systems – yet it has remained severely limited in its applicability to more complex systems. We address the main problems of HyTech with PHAVer, a new tool for the exact verification of safety properties of hybrid systems with piecewise constant bounds on the derivatives. Affine dynamics are handled by on-the-fly overapproximation and by partitioning the state space based on user-definable constraints and the dynamics of the system. PHAVer's exact arithmetic is robust due to the use of the Parma Polyhedra Library, which supports arbitrarily large numbers. To manage the complexity of the polyhedral computations, we propose methods to conservatively limit the number of bits and constraints of polyhedra. Experimental results for a navigation benchmark and a tunnel diode circuit show the effectiveness of the approach.

560 citations

Cites methods from "HYTECH: a model checker for hybrid ..."

  • ...presented the tool HyTech [1]....

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  • ...We present PHAVer (Polyhedral Hybrid Automaton Verifier), a verification tool that aims at overcoming the limitations of predecessors such as as HyTech [1]....

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  • ...The initial states for for NAV01–NAV03 are defined by x0 ∈ [2, 3] × [1, 2], for NAV04 by x0 ∈ [0, 1] × [0, 1], and v0,NAV01 ∈ [−0....

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Journal Article•DOI•
The Parma Polyhedra Library: Toward a complete set of numerical abstractions for the analysis and verification of hardware and software systems

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Roberto Bagnara1, Patricia M. Hill2, Enea Zaffanella1•
University of Parma1, University of Leeds2
01 Jun 2008-Science of Computer Programming
TL;DR: The main features of the current version of the Parma Polyhedra Library are presented, emphasizing those that distinguish it from other similar libraries and those that are important for applications in the field of analysis and verification of hardware and software systems.

518 citations

Cites background from "HYTECH: a model checker for hybrid ..."

  • ...04f) [59]; 4 • the Octagon Abstract Domain Library (version 0....

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References
More filters
Journal Article•DOI•
A theory of timed automata

[...]

Rajeev Alur1, David L. Dill1•
Stanford University1
25 Apr 1994-Theoretical Computer Science
TL;DR: Alur et al. as discussed by the authors proposed timed automata to model the behavior of real-time systems over time, and showed that the universality problem and the language inclusion problem are solvable only for the deterministic automata: both problems are undecidable (II i-hard) in the non-deterministic case and PSPACE-complete in deterministic case.

7,096 citations

Book Chapter•DOI•
Design and Synthesis of Synchronization Skeletons Using Branching-Time Temporal Logic

[...]

Edmund M. Clarke1, E. Allen Emerson1•
Harvard University1
01 May 1981
TL;DR: It is shown that it is possible to automatically synthesize the synchronization skeleton of a concurrent program from a Temporal Logic specification and it is believed that this approach may in the long run turn out to be quite practical.
Abstract: We have shown that it is possible to automatically synthesize the synchronization skeleton of a concurrent program from a Temporal Logic specification We believe that this approach may in the long run turn out to be quite practical Since synchronization skeletons are, in general, quite small, the potentially exponential behavior of our algorithm need not be an insurmountable obstacle Much additional research will be needed, however, to make the approach feasible in practice

2,333 citations

Journal Article•DOI•
The algorithmic analysis of hybrid systems

[...]

Rajeev Alur1, Costas Courcoubetis2, Nicolas Halbwachs, Thomas A. Henzinger3, Pei Ho3, Xavier Nicollin, Alfredo Olivero, Joseph Sifakis, Sergio Yovine •
Bell Labs1, University of Crete2, Cornell University3
06 Feb 1995-Theoretical Computer Science
TL;DR: A general framework for the formal specification and algorithmic analysis of hybrid systems is presented, which considers symbolic model-checking and minimization procedures that are based on the reachability analysis of an infinite state space.

2,091 citations

"HYTECH: a model checker for hybrid ..." refers background or methods in this paper

  • ...x= 2∧y = 0∧z = 0 ∧ ẋ ∈ [2, 4]∧ ẏ = 1∧ ż = 1∧x = x+ δẋ ∧ y = y+ δẏ∧z = z+ δż = (∃ δ ≥0....

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  • ...For modeling more general kinds of hybrid systems, we use the hybrid automaton – a finite automaton with a finite number of real-valued variables that change continuously, as specified by differential equations and differential inequalities, in more general ways than clocks [2, 3, 36]....

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  • ...A hybrid automaton is a systemA= (X,V,flow , inv , init , E, jump,Σ, syn) that consists of the following components [2]:...

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  • ...Relaxation, then, yields the linear flow conditions ẋ ∈ [3, 4] for on1 and ẋ ∈ [2, 3] for on2....

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  • ...Hence the flow condition ẋ=−x+5 can be relaxed to the linear condition ẋ ∈ [2, 4]....

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Proceedings Article•DOI•
The theory of hybrid automata

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Thomas A. Henzinger1•
University of California, Berkeley1
27 Jul 1996
TL;DR: The goal is to demonstrate that concepts from the theory of discrete concurrent systems can give insights into partly continuous systems, and that methods for the verification of finite-state systems can be used to analyze certain systems with uncountable state spaces.
Abstract: We summarize several recent results about hybrid automata. Our goal is to demonstrate that concepts from the theory of discrete concurrent systems can give insights into partly continuous systems, and that methods for the verification of finite-state systems can be used to analyze certain systems with uncountable state spaces.

1,900 citations

Book Chapter•DOI•
Specification and verification of concurrent systems in CESAR

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Jean-Pierre Queille, Joseph Sifakis
06 Apr 1982
TL;DR: By an example, the alternating bit protocol, the use of CESAR, an interactive system for aiding the design of distributed applications, is illustrated.
Abstract: The aim of this paper is to illustrate by an example, the alternating bit protocol, the use of CESAR, an interactive system for aiding the design of distributed applications

1,509 citations

Related Papers (5)
A theory of timed automata

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The algorithmic analysis of hybrid systems

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01 Dec 1997-International Journal on Software Tools for Technology Transfer
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Model checking

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