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51
Alternatingtime Temporal Logic
 Journal of the ACM
, 1997
"... Temporal logic comes in two varieties: lineartime temporal logic assumes implicit universal quantification over all paths that are generated by system moves; branchingtime temporal logic allows explicit existential and universal quantification over all paths. We introduce a third, more general var ..."
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Cited by 448 (47 self)
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Temporal logic comes in two varieties: lineartime temporal logic assumes implicit universal quantification over all paths that are generated by system moves; branchingtime temporal logic allows explicit existential and universal quantification over all paths. We introduce a third, more general variety of temporal logic: alternatingtime temporal logic offers selective quantification over those paths that are possible outcomes of games, such as the game in which the system and the environment alternate moves. While lineartime and branchingtime logics are natural specification languages for closed systems, alternatingtime logics are natural specification languages for open systems. For example, by preceding the temporal operator "eventually" with a selective path quantifier, we can specify that in the game between the system and the environment, the system has a strategy to reach a certain state. Also the problems of receptiveness, realizability, and controllability can be formulated as modelchecking problems for alternatingtime formulas.
METATEM: A Framework for Programming in Temporal Logic
 In REX Workshop on Stepwise Refinement of Distributed Systems: Models, Formalisms, Correctness (LNCS Volume 430
, 1989
"... In this paper we further develop the methodology of temporal logic as an executable imperative language, presented by Moszkowski [Mos86] and Gabbay [Gab87, Gab89] and present a concrete framework, called METATEM for executing (modal and) temporal logics. Our approach is illustrated by the developmen ..."
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Cited by 88 (20 self)
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In this paper we further develop the methodology of temporal logic as an executable imperative language, presented by Moszkowski [Mos86] and Gabbay [Gab87, Gab89] and present a concrete framework, called METATEM for executing (modal and) temporal logics. Our approach is illustrated by the development of an execution mechanism for a propositional temporal logic and for a restricted first order temporal logic.
Synthesizing StateBased Object Systems from LSC Specifications
, 2000
"... Live sequence charts (LSCs) have been de ned recently as an extension of message sequence charts (MSCs � or their UML variant, sequence diagrams) for rich interobject speci cation. One of the main additions is the notion of universal charts and hot, mandatory behavior, which, among other things, en ..."
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Cited by 83 (23 self)
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Live sequence charts (LSCs) have been de ned recently as an extension of message sequence charts (MSCs � or their UML variant, sequence diagrams) for rich interobject speci cation. One of the main additions is the notion of universal charts and hot, mandatory behavior, which, among other things, enables one to specify forbidden scenarios. LSCs are thus essentially as expressive as statecharts. This paper deals with synthesis, which is the problem of deciding, given an LSC speci cation, if there exists a satisfying object system and, if so, to synthesize one automatically. The synthesis problem is crucial in the development of complex systems, since sequence diagrams serve as the manifestation of use cases  whether used formally or informally  and if synthesizable they could lead directly to implementation. Synthesis is considerably harder for LSCs than for MSCs, and we tackle it by de ning consistency, showing that an entire LSC speci cation is consistent i it is satis able by a statebased object system, and then synthesizing a satisfying system as a collection of nite state machines or statecharts. 1
Generalized Model Checking: Reasoning about Partial State Spaces
, 2000
"... We discuss the problem of model checking temporal properties on partial Kripke structures, which were used in [BG99] to represent incomplete state spaces. We first extend the results of [BG99] by showing that the modelchecking problem for any 3valued temporal logic can be reduced to two modelchec ..."
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Cited by 74 (6 self)
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We discuss the problem of model checking temporal properties on partial Kripke structures, which were used in [BG99] to represent incomplete state spaces. We first extend the results of [BG99] by showing that the modelchecking problem for any 3valued temporal logic can be reduced to two modelchecking problems for the corresponding 2valued temporal logic. We then introduce a new semantics for 3valued temporal logics that can give more definite answers than the previous one. With this semantics, the evaluation of a formula OE on a partial Kripke structure M returns the third truth value? (read "unknown") only if there exist Kripke structures M1 and M2 that both complete M and such that M1 satisfies OE while M2 violates OE, hence making the value of OE on M truly unknown. The partial Kripke structure M can thus be viewed as a partial solution to the satisfiability problem which reduces the solution space to complete Kripke structures that are more complete than M wit...
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 70 (6 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...
Conversation Protocols: A Formalism for Specification and Verification of Reactive Electronic Services
 In Proc. Int. Conf. on Implementation and Application of Automata (CIAA
, 2004
"... This paper focuses on the realizability problem of a framework for modeling and specifying the global behaviors of reactive electronic services (eservices). In this framework, Web accessible programs (peers) communicate by asynchronous message passing, and a virtual global watcher silently listens ..."
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Cited by 70 (17 self)
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This paper focuses on the realizability problem of a framework for modeling and specifying the global behaviors of reactive electronic services (eservices). In this framework, Web accessible programs (peers) communicate by asynchronous message passing, and a virtual global watcher silently listens to the network. The global behavior is characterized by a "conversation", which is the infinite sequence of messages observed by the watcher. We show that given a Buchi automaton specifying the desired set of conversations, called a "conversation protocol", it is possible to realize the protocol using a set of finite state peers if three realizability conditions are satisfied. In particular, the synthesized peers will conform to the protocol by generating only those conversations specified by the protocol. Our results enable a topdown verification strategy where (1) A conversation protocol is specified by a realizable Buchi automaton, (2) The properties of the protocol are verified on the Buchi automaton specification, and (3) The peer implementations are synthesized from the protocol via projection.
Tractable Multiagent Planning for Epistemic Goals
 In Proceedings of the First International Joint Conference on Autonomous Agents and Multiagent Systems (AAMAS2002
, 2002
"... agent or group of agents. In this paper, we address the problem of how plans might be developed for a group of agents to cooperate to bring about such a goal. We present a novel approach to this problem, in which the problem is formulated as one of model checking in Alternating Temporal Epistemic Lo ..."
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Cited by 67 (10 self)
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agent or group of agents. In this paper, we address the problem of how plans might be developed for a group of agents to cooperate to bring about such a goal. We present a novel approach to this problem, in which the problem is formulated as one of model checking in Alternating Temporal Epistemic Logic (ATEL). After introducing this logic, we present a model checking algorithm for it, and show that the model checking problem for this logic is tractable. We then show how multiagent planning can be treated as a model checking problem in ATEL, and discuss the related issue of checking knowledge preconditions for multiagent plans. We illustrate the approach with an example. We then describe how this example was implemented using the MOCHA model checking system, and conclude by discussing the relationship of our work with that of others in the planning and speech acts communities.
Synthesis of reactive(1) designs
 In Proc. Verification, Model Checking, and Abstract Interpretation (VMCAI’06
, 2006
"... Abstract. We consider the problem of synthesizing digital designs from their LTL specification. In spite of the theoretical double exponential lower bound for the general case, we show that for many expressive specifications of hardware designs the problem can be solved in time N 3, where N is the s ..."
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Cited by 54 (7 self)
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Abstract. We consider the problem of synthesizing digital designs from their LTL specification. In spite of the theoretical double exponential lower bound for the general case, we show that for many expressive specifications of hardware designs the problem can be solved in time N 3, where N is the size of the state space of the design. We describe the context of the problem, as part of the Prosyd European Project which aims to provide a propertybased development flow for hardware designs. Within this project, synthesis plays an important role, first in order to check whether a given specification is realizable, and then for synthesizing part of the developed system. The class of LTL formulas considered is that of Generalized Reactivity(1) (generalized Streett(1)) formulas, i.e., formulas of the form: ( p1 ∧ · · · ∧ pm) → ( q1 ∧ · · · ∧ qn) where each pi, qi is a boolean combination of atomic propositions. We also consider the more general case in which each pi, qi is an arbitrary past LTL formula over atomic propositions. For this class of formulas, we present an N 3time algorithm which checks whether such a formula is realizable, i.e., there exists a circuit which satisfies the formula under any set of inputs provided by the environment. In the case that the specification is realizable, the algorithm proceeds to construct an automaton which represents one of the possible implementing circuits. The automaton is computed and presented symbolically. 1
Automated Composition of Web Services by Planning in Asynchronous Domains
 In 15th Intl. Conference on Automated Planning and Scheduling
, 2005
"... We propose a novel planning framework for the automated composition of web services. We consider services that are specified and implemented in industrial standard languages for business processes modeling and execution, like BPEL4WS. These languages describe web services whose behavior is intrinsic ..."
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Cited by 48 (8 self)
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We propose a novel planning framework for the automated composition of web services. We consider services that are specified and implemented in industrial standard languages for business processes modeling and execution, like BPEL4WS. These languages describe web services whose behavior is intrinsically asynchronous. For this reason, the key aspect of our framework is the modeling of asynchronous planning problems. In the paper we describe the framework and propose a planning approach that is based on state of the art techniques for planning under uncertainty. Our experiments show that this approach can scale up to significant cases, i.e., to cases in which the manual development of BPEL4WS composed services is not trivial and is time consuming.
Synthesizing Distributed Systems
, 2001
"... In system synthesis, we transform a specication into a system that is guaranteed to satisfy the speci cation. When the system is distributed, the goal is to construct the system's underlying processes. Results on multiplayer games imply that the synthesis problem for linear specications is undecid ..."
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Cited by 42 (1 self)
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In system synthesis, we transform a specication into a system that is guaranteed to satisfy the speci cation. When the system is distributed, the goal is to construct the system's underlying processes. Results on multiplayer games imply that the synthesis problem for linear specications is undecidable for general architectures, and is nonelementary decidable for hierarchical architectures, where the processes are linearly ordered and information among them ows in one direction. In this paper we present a signicant extension of this result. We handle both linear and branching specications, and we show that a sucient condition for decidability of the synthesis problem is a linear or cyclic order among the processes, in which information ows in either one or both directions. We also allow the processes to have internal hidden variables, and we consider communications with and without delay. Many practical applications fall into this class. 1 Introduction In system synthesis, we...