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243
Timed Transition Systems
, 1992
"... . We incorporate time into an interleaving model of concurrency. In timed transition systems, the qualitative fairness requirements of traditional transition system are replaced (and superseded) by quantitative lowerbound and upperbound timing constraints on transitions. The purpose of this paper i ..."
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Cited by 92 (6 self)
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. We incorporate time into an interleaving model of concurrency. In timed transition systems, the qualitative fairness requirements of traditional transition system are replaced (and superseded) by quantitative lowerbound and upperbound timing constraints on transitions. The purpose of this paper is to explore the scope of applicability for the abstract model of timed transition systems. We demonstrate that the model can represent a wide variety of phenomena that routinely occur in conjunction with the timed execution of concurrent processes. Our treatment covers both processes that are executed in parallel on separate processors and communicate either through shared variables or by message passing, and processes that timeshare a limited number of processors under a given scheduling policy. Often it is this scheduling policy that determines if a system meets its realtime requirements. Thus we explicitly address such questions as timeouts, interrupts, static and dynamic priorities. ...
The ForSpec Temporal Logic: A New Temporal PropertySpecification Language
, 2001
"... In this paper we describe the ForSpec Temporal Logic (FTL), the new temporal propertyspecification logic of ForSpec, Intel's new formal specification language. The key features of FTL are as follows: it is a linear temporal logic, based on Pnueli's LTL, it is based on a rich set of log ..."
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Cited by 89 (23 self)
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In this paper we describe the ForSpec Temporal Logic (FTL), the new temporal propertyspecification logic of ForSpec, Intel's new formal specification language. The key features of FTL are as follows: it is a linear temporal logic, based on Pnueli's LTL, it is based on a rich set of logical and arithmetical operations on bit vectors to describe state properties, it enables the user to define temporal connectives over time windows, it enables the user to define regular events, which are regular sequences of Boolean events, and then relate such events via special connectives, it enables the user to express properties about the past, and it includes constructs that enable the user to model multiple clock and reset signals, which is useful in the verification of hardware design.
TimeConstrained Automata
 CONCUR '91: 2nd International Conference on Concurrency Theory, volume 527 of Lecture Notes in Computer Science
, 1991
"... ) Michael Merritt AT&T Bell Laboratories 600 Mountain Avenue Murray Hill, NJ 07974 merritt@research.att.com Francesmary Modugno School of Computer Science Carnegie Mellon University Pittsburgh, PA 15213 fmm@cs.cmu.edu Mark R. Tuttle DEC Cambridge Research Lab One Kendall Sq., Bldg. 700 Camb ..."
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Cited by 88 (0 self)
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) Michael Merritt AT&T Bell Laboratories 600 Mountain Avenue Murray Hill, NJ 07974 merritt@research.att.com Francesmary Modugno School of Computer Science Carnegie Mellon University Pittsburgh, PA 15213 fmm@cs.cmu.edu Mark R. Tuttle DEC Cambridge Research Lab One Kendall Sq., Bldg. 700 Cambridge, MA 02139 tuttle@crl.dec.com Abstract In this paper, we augment the inputoutput automaton model in order to reason about time in concurrent systems, and we prove simple properties of this augmentation. The inputoutput automata model is a useful model for reasoning about computation in concurrent and distributed systems because it allows fundamental properties such as fairness and compositionality to be expressed easily and naturally. A unique property of the model is that systems are modeled as the composition of autonomous components. This paper describes a way to add a notion of time to the model in a way that preserves these properties. The result is a simple, compositional model fo...
Planning Control Rules for Reactive Agents
 Artificial Intelligence
, 1997
"... A traditional approach for planning is to evaluate goal statements over state trajectories modeling predicted behaviors of an agent. This paper describes a powerful extension of this approach for handling complex goals for reactive agents. We describe goals by using a modal temporal logic that can e ..."
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Cited by 84 (8 self)
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A traditional approach for planning is to evaluate goal statements over state trajectories modeling predicted behaviors of an agent. This paper describes a powerful extension of this approach for handling complex goals for reactive agents. We describe goals by using a modal temporal logic that can express quite complex time, safety, and liveness constraints. Our method is based on an incremental planner algorithm that generates a reactive plan by computing a sequence of partially satisfactory reactive plans converging to a completely satisfactory one. Partial satisfaction means that an agent controlled by the plan accomplishes its goal only for some environment events. Complete satisfaction means that the agent accomplishes its goal whatever environment events occur during the execution of the plan. As such, our planner can be stopped at any time to yield a useful plan. An implemented prototype is used to evaluate our planner on empirical problems. Keywords: Planning, control, reactiv...
Integration Graphs: A Class of Decidable Hybrid Systems
 In Hybrid Systems, volume 736 of Lecture Notes in Computer Science
, 1993
"... . Integration Graphs are a computational model developed in the attempt to identify simple Hybrid Systems with decidable analysis problems. We start with the class of constant slope hybrid systems (cshs), in which the right hand side of all differential equations is an integer constant. We refer to ..."
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Cited by 72 (9 self)
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. Integration Graphs are a computational model developed in the attempt to identify simple Hybrid Systems with decidable analysis problems. We start with the class of constant slope hybrid systems (cshs), in which the right hand side of all differential equations is an integer constant. We refer to continuous variables whose right hand side constants are always 1 as timers. All other continuous variables are called integrators. The first result shown in the paper is that simple questions such as reachability of a given state are undecidable for even this simple class of systems. To restrict the model even further, we impose the requirement that no test that refers to integrators may appear within a loop in the graph. This restricted class of cshs is called integration graphs . The main results of the paper are that the reachability problem of integration graphs is decidable for two special cases: The case of a single timer and the case of a single test involving integrators. The expres...
Temporal Proof Methodologies for Realtime Systems
 In Proceedings of the 18th Annual Symposium on Principles of Programming Languages
, 1991
"... . We extend the specification language of temporal logic, the corresponding verification framework, and the underlying computational model to deal with realtime properties of concurrent and reactive systems. A global, discrete, and asynchronous clock is incorporated into the model by defining the a ..."
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Cited by 68 (11 self)
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. We extend the specification language of temporal logic, the corresponding verification framework, and the underlying computational model to deal with realtime properties of concurrent and reactive systems. A global, discrete, and asynchronous clock is incorporated into the model by defining the abstract notion of a realtime transition system as a conservative extension of traditional transition systems: qualitative fairness requirements are replaced (and superseded) by quantitative lowerbound and upperbound realtime requirements for transitions. We show how to model realtime systems that communicate either through shared variables or by message passing, and how to represent the important realtime constructs of priorities (interrupts), scheduling, and timeouts in this framework. Two styles for the specification of realtime properties are presented. The first style uses bounded versions of the temporal operators; the realtime requirements expressed in this style are classified ...
On the decidability of metric temporal logic
 In Proc. LICS
, 2005
"... Metric Temporal Logic (MTL) is a prominent specification formalism for realtime systems. In this paper, we show that the satisfiability problem for MTL over finite timed words is decidable, with nonprimitive recursive complexity. We also consider the modelchecking problem for MTL: whether all w ..."
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Cited by 67 (11 self)
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Metric Temporal Logic (MTL) is a prominent specification formalism for realtime systems. In this paper, we show that the satisfiability problem for MTL over finite timed words is decidable, with nonprimitive recursive complexity. We also consider the modelchecking problem for MTL: whether all words accepted by a given AlurDill timed automaton satisfy a given MTL formula. We show that this problem is decidable over finite words. Over infinite words, we show that model checking the safety fragment of MTLâ€”which includes invariance and timebounded response propertiesâ€”is also decidable. These results are quite surprising in that they contradict various claims to the contrary that have appeared in the literature. The question of the decidability of MTL over infinite words remains open. 1.
Towards monitoringoriented programming: A paradigm combining specification and implementation
 Electronic Notes in Theoretical Computer Science
, 2003
"... Implementation ..."
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An AutomataTheoretic Approach to Presburger Arithmetic Constraints (Extended Abstract)
 In Proc. Static Analysis Symposium, LNCS 983
, 1995
"... This paper introduces a finiteautomata based representation of Presburger arithmetic definable sets of integer vectors. The representation consists of concurrent automata operating on the binary encodings of the elements of the represented sets. This representation has several advantages. First, be ..."
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Cited by 60 (5 self)
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This paper introduces a finiteautomata based representation of Presburger arithmetic definable sets of integer vectors. The representation consists of concurrent automata operating on the binary encodings of the elements of the represented sets. This representation has several advantages. First, being automatabased it is operational in nature and hence leads directly to algorithms, for instance all usual operations on sets of integer vectors translate naturally to operations on automata. Second, the use of concurrent automata makes it compact. Third, it is insensitive to the representation size of integers. Our representation can be used whenever arithmetic constraints are needed. To il...
Specifying Timed State Sequences in Powerful Decidable Logics and Timed Automata (Extended Abstract)
 LNCS 863
, 1994
"... ) Thomas Wilke ChristianAlbrechtsUniversitat zu Kiel, Institut fur Informatik und Praktische Mathematik, D24098 Kiel, Germany ? Abstract. A monadic secondorder language, denoted by Ld, is introduced for the specification of sets of timed state sequences. A fragment of Ld, denoted by L $ d, is ..."
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Cited by 58 (0 self)
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) Thomas Wilke ChristianAlbrechtsUniversitat zu Kiel, Institut fur Informatik und Praktische Mathematik, D24098 Kiel, Germany ? Abstract. A monadic secondorder language, denoted by Ld, is introduced for the specification of sets of timed state sequences. A fragment of Ld, denoted by L $ d, is proved to be expressively complete for timed automata (Alur and Dill), i. e., every timed regular language is definable by a L $ dformula and every L $ dformula defines a timed regular language. As a consequence the satisfiability problem for L $ d is decidable. Timed temporal logics are shown to be effectively embeddable into L $ d and hence turn out to have a decidable theory. This applies to TL \Gamma (Manna and Pnueli) and EMITLp , which is obtained by extending the logic MITLp (Alur and Henzinger) by automata operators (Sistla, Vardi, and Wolper). For every positive natural number k the full monadic secondorder logic Ld and L $ d are equally expressive modulo the set of timed...