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385
A theory of timed automata
, 1999
"... Model checking is emerging as a practical tool for automated debugging of complex reactive systems such as embedded controllers and network protocols (see [23] for a survey). Traditional techniques for model checking do not admit an explicit modeling of time, and are thus, unsuitable for analysis of ..."
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Cited by 1975 (31 self)
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Model checking is emerging as a practical tool for automated debugging of complex reactive systems such as embedded controllers and network protocols (see [23] for a survey). Traditional techniques for model checking do not admit an explicit modeling of time, and are thus, unsuitable for analysis of realtime systems whose correctness depends on relative magnitudes of different delays. Consequently, timed automata [7] were introduced as a formal notation to model the behavior of realtime systems. Its definition provides a simple way to annotate statetransition graphs with timing constraints using finitely many realvalued clock variables. Automated analysis of timed automata relies on the construction of a finite quotient of the infinite space of clock valuations. Over the years, the formalism has been extensively studied leading to many results establishing connections to circuits and logic, and much progress has been made in developing verification algorithms, heuristics, and tools. This paper provides a survey of the theory of timed automata, and their role in specification and verification of realtime systems.
Model Checking Programs
, 2003
"... The majority of work carried out in the formal methods community throughout the last three decades has (for good reasons) been devoted to special languages designed to make it easier to experiment with mechanized formal methods such as theorem provers, proof checkers and model checkers. In this pape ..."
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Cited by 462 (60 self)
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The majority of work carried out in the formal methods community throughout the last three decades has (for good reasons) been devoted to special languages designed to make it easier to experiment with mechanized formal methods such as theorem provers, proof checkers and model checkers. In this paper we will attempt to give convincing arguments for why we believe it is time for the formal methods community to shift some of its attention towards the analysis of programs written in modern programming languages. In keeping with this philosophy we have developed a verification and testing environment for Java, called Java PathFinder (JPF), which integrates model checking, program analysis and testing. Part of this work has consisted of building a new Java Virtual Machine that interprets Java bytecode. JPF uses state compression to handle big states, and partial order and symmetry reduction, slicing, abstraction, and runtime analysis techniques to reduce the state space. JPF has been applied to a realtime avionics operating system developed at Honeywell, illustrating an intricate error, and to a model of a spacecraft controller, illustrating the combination of abstraction, runtime analysis, and slicing with model checking.
Model Checking in CLP
, 1999
"... We show that Constraint Logic Programming (CLP) can serve as a conceptual basis and as a practical implementation platform for the model checking of infinitestate systems. Our contributions are: (1) a semanticspreserving translation of concurrent systems into CLP programs, (2) a method for verifyi ..."
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Cited by 90 (27 self)
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We show that Constraint Logic Programming (CLP) can serve as a conceptual basis and as a practical implementation platform for the model checking of infinitestate systems. Our contributions are: (1) a semanticspreserving translation of concurrent systems into CLP programs, (2) a method for verifying safety and liveness properties on the CLP programs produced by the translation. We have implemented the method in a CLP system and verified wellknown examples of infinitestate programs over integers, using here linear constraints as opposed to Presburger arithmetic as in previous solutions.
Automatic verification of realtime systems with discrete probability distributions
 Theoretical Computer Science
, 1999
"... Abstract. We consider the timed automata model of [3], which allows the analysis of realtime systems expressed in terms of quantitative timing constraints. Traditional approaches to realtime system description express the model purely in terms of nondeterminism; however, we may wish to express the ..."
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Cited by 72 (27 self)
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Abstract. We consider the timed automata model of [3], which allows the analysis of realtime systems expressed in terms of quantitative timing constraints. Traditional approaches to realtime system description express the model purely in terms of nondeterminism; however, we may wish to express the likelihood of the system making certain transitions. In this paper, we present a model for realtime systems augmented with discrete probability distributions. Furthermore, using the algorithm of [5] with fairness, we develop a model checking method for such models against temporal logic properties which can refer both to timing properties and probabilities, such as, “with probability 0.6 or greater, the clock x remains below 5 until clock y exceeds 2”. 1
PRISM 4.0: Verification of Probabilistic Realtime Systems
"... Abstract. This paper describes a major new release of the PRISM probabilistic model checker, adding, in particular, quantitative verification of (priced) probabilistic timed automata. These model systems exhibiting probabilistic, nondeterministic and realtime characteristics. In many application do ..."
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Cited by 64 (16 self)
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Abstract. This paper describes a major new release of the PRISM probabilistic model checker, adding, in particular, quantitative verification of (priced) probabilistic timed automata. These model systems exhibiting probabilistic, nondeterministic and realtime characteristics. In many application domains, all three aspects are essential; this includes, for example, embedded controllers in automotive or avionic systems, wireless communication protocols such as Bluetooth or Zigbee, and randomised security protocols. PRISM, which is opensource, also contains several new components that are of independent use. These include: an extensible toolkit for building, verifying and refining abstractions of probabilistic models; an explicitstate probabilistic model checking library; a discreteevent simulation engine for statistical model checking; support for generation of optimal adversaries/strategies; and a benchmark suite. 1
Linear Parametric Model Checking of Timed Automata
, 2002
"... We present an extension of the model checker Uppaal, capable of synthesizing linear parameter constraints for the correctness of parametric timed automata. A symbolic representation of the (parametric) state space in terms of parametric difference bound matrices is shown to be correct. A second cont ..."
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Cited by 61 (3 self)
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We present an extension of the model checker Uppaal, capable of synthesizing linear parameter constraints for the correctness of parametric timed automata. A symbolic representation of the (parametric) state space in terms of parametric difference bound matrices is shown to be correct. A second contribution of this paper is the identification of a subclass of parametric timed automata (L/U automata), for which the emptiness problem is decidable, contrary to the full class where it is known to be undecidable. Also, we present a number of results that reduce the verification effort for L/U automata in certain cases. We illustrate our approach by deriving linear parameter constraints for a number of wellknown case studies from the literature (exhibiting a flaw in a published paper).
Scheduling a Steel Plant with Timed Automata
 In Sixth International Conference on RealTime Computing Systems and Applications (RTCSA’99). IEEE Computer
, 1999
"... Scheduling in an environment with constraints of many different types is known to be a hard problem. We tackle this problem for an integrated steel plant in Ghent, Belgium, using UPPAAL, a model checker for networks of timed automata. We show how to translate schedulability to reachability, enabling ..."
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Cited by 57 (5 self)
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Scheduling in an environment with constraints of many different types is known to be a hard problem. We tackle this problem for an integrated steel plant in Ghent, Belgium, using UPPAAL, a model checker for networks of timed automata. We show how to translate schedulability to reachability, enabling us to use UPPAAL's model checking algorithms. 1. Introduction This report is a result of the participation of CSI Nijmegen in the European Union Esprit long term research project Verification of Hybrid Systems (http://wwwverimag. imag.fr//VHS/). The Esprit program was set up to improve the takeup of modern information technologies in industry. The VHS project in particular is meant to stimulate research in the area of hybrid systems. These systems typically consist of digital components in a continuous environment. The correct behavior depends strongly on the interaction between the digital components, say the controller, and the controlled process. Hybrid systems are important in numero...
A brief history of process algebra
 Theor. Comput. Sci
, 2004
"... Abstract. This note addresses the history of process algebra as an area of research in concurrency theory, the theory of parallel and distributed systems in computer science. Origins are traced back to the early seventies of the twentieth century, and developments since that time are sketched. The a ..."
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Cited by 56 (1 self)
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Abstract. This note addresses the history of process algebra as an area of research in concurrency theory, the theory of parallel and distributed systems in computer science. Origins are traced back to the early seventies of the twentieth century, and developments since that time are sketched. The author gives his personal views on these matters. He also considers the present situation, and states some challenges for the future.
Hierarchical Modeling and Analysis of Embedded Systems
, 2003
"... This paper describes the modeling language CHARON for modular design of interacting hybrid systems. The language allows specification of architectural as well as behavioral hierarchy and discrete as well as continuous activities. The modular structure of the language is not merely syntactic, but is ..."
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Cited by 55 (19 self)
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This paper describes the modeling language CHARON for modular design of interacting hybrid systems. The language allows specification of architectural as well as behavioral hierarchy and discrete as well as continuous activities. The modular structure of the language is not merely syntactic, but is exploited by analysis tools and is supported by a formal semantics with an accompanying compositional theory of refinement. We illustrate the benefits of CHARON in the design of embedded control software using examples from automated highways concerning vehicle coordination
Guided Synthesis of Control Programs Using UPPAAL
, 2000
"... In this paper we address the problem of scheduling and synthesizing distributed control programs for a batch production plant. We use a timed automata model of the batch plant and the verification tool UPPAAL to solve the scheduling problem. The plant model aims at faithfully reflecting the level of ..."
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Cited by 52 (26 self)
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In this paper we address the problem of scheduling and synthesizing distributed control programs for a batch production plant. We use a timed automata model of the batch plant and the verification tool UPPAAL to solve the scheduling problem. The plant model aims at faithfully reflecting the level of abstraction required for synthesizing control programs from generated timed traces. Therefore it quickly becomes too detailed and complicated for automatic synthesis. To solve this problem we present a general way of adding guidance to a model by augmenting it with additional guidance variables and decorating the transitions with extra guards. Applying this technique have made synthesis of control programs feasible for a plant producing as many as 60 batches. In comparison, we could only handle plants producing two batches without using guides. The synthesized control programs have been executed in a physical plant. This proved useful in validating the correctness of the plant model and in ...