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The Temporal Logic Sugar
, 2001
"... Introduction Since the introduction of temporal logic for the specication of computer programs [5], usability has been an issue, because a diculttouse formalism is a barrier to the wide adoption of formal methods. Our solution is Sugar, the temporal logic used by the RuleBase formal verication to ..."
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Cited by 66 (8 self)
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Introduction Since the introduction of temporal logic for the specication of computer programs [5], usability has been an issue, because a diculttouse formalism is a barrier to the wide adoption of formal methods. Our solution is Sugar, the temporal logic used by the RuleBase formal verication tool [2]. Sugar adds the power of regular expressions to CTL [4], as well as an extensive set of operators which provide syntactic sugar. That is, while these operators do not add expressive power, they allow properties to be expressed more succinctly than in the basic language. Experience shows that Sugar allows hardware engineers to easily and intuitively specify their designs. The full language is used for model checking, and a signicant portion can be model checked onthey [3]. The automatic generation of simulation checkers from the same portion of Sugar is described in [1]. While previous papers have described various features of the language, this paper pres
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 un ..."
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Cited by 49 (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...
A logical model of social commitment for agent communication
 Proc. Second International Joint Conference on Autonomous Agents and Multiagent Systems (AAMAS 2003
, 2003
"... As part of the goal of developing a genuinely open multiagent system, many efforts are devoted to the definition of a standard Agent Communication Language (ACL). The aim of this paper is to propose a logical framework for the definition of ACL semantics based upon the concept of (social) commitment ..."
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Cited by 47 (7 self)
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As part of the goal of developing a genuinely open multiagent system, many efforts are devoted to the definition of a standard Agent Communication Language (ACL). The aim of this paper is to propose a logical framework for the definition of ACL semantics based upon the concept of (social) commitment. Our framework relies on the assumption that agent communication should be analyzed in terms of communicative acts, by means of which agents create and manipulate commitments, provided certain contextual conditions hold. We propose formal definitions of such actions in the context of a temporal logic that extends CTL ∗ with pastdirected temporal operators. In the system we propose, called CTL±, time is assumed to be discrete, with no start or end point, and branching in the future. CTL ± is then extended to represent actions and commitments; in particular, we formally define the conditions under which a commitment is fulfilled or violated. Finally, we show how our logic of commitment can be used to define the semantics of an ACL.
Differential Dynamic Logic for Hybrid Systems
, 2007
"... Hybrid systems are models for complex physical systems and are defined as dynamical systems with interacting discrete transitions and continuous evolutions along differential equations. With the goal of developing a theoretical and practical foundation for deductive verification of hybrid systems, ..."
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Cited by 45 (33 self)
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Hybrid systems are models for complex physical systems and are defined as dynamical systems with interacting discrete transitions and continuous evolutions along differential equations. With the goal of developing a theoretical and practical foundation for deductive verification of hybrid systems, we introduce a dynamic logic for hybrid programs, which is a program notation for hybrid systems. As a verification technique that is suitable for automation, we introduce a free variable proof calculus with a novel combination of realvalued free variables and Skolemisation for lifting quantifier elimination for real arithmetic to dynamic logic. The calculus is compositional, i.e., it reduces properties of hybrid programs to properties of their parts. Our main result proves that this calculus axiomatises the transition behaviour of hybrid systems completely relative to differential equations. In a case study with cooperating traffic agents of the European Train Control System, we further show that our calculus is wellsuited for verifying realistic hybrid systems with parametric system dynamics.
Automated Temporal Reasoning about Reactive Systems
, 1996
"... . There is a growing need for reliable methods of designing correct reactive systems such as computer operating systems and air traffic control systems. It is widely agreed that certain formalisms such as temporal logic, when coupled with automated reasoning support, provide the most effective a ..."
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Cited by 40 (2 self)
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. There is a growing need for reliable methods of designing correct reactive systems such as computer operating systems and air traffic control systems. It is widely agreed that certain formalisms such as temporal logic, when coupled with automated reasoning support, provide the most effective and reliable means of specifying and ensuring correct behavior of such systems. This paper discusses known complexity and expressiveness results for a number of such logics in common use and describes key technical tools for obtaining essentially optimal mechanical reasoning algorithms. However, the emphasis is on underlying intuitions and broad themes rather than technical intricacies. 1 Introduction There is a growing need for reliable methods of designing correct reactive systems. These systems are characterized by ongoing, typically nonterminating and highly nondeterministic behavior. Examples include operating systems, network protocols, and air traffic control systems. There is w...
Model checking and the Mucalculus
 DIMACS Series in Discrete Mathematics
, 1997
"... There is a growing recognition of the need to apply formal mathematical methods in the design of "high confidence" computing systems. Such systems operate in safety critical contexts (e.g., air traffic control systems) or where errors could have major adverse economic consequences (e.g., ..."
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Cited by 37 (0 self)
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There is a growing recognition of the need to apply formal mathematical methods in the design of "high confidence" computing systems. Such systems operate in safety critical contexts (e.g., air traffic control systems) or where errors could have major adverse economic consequences (e.g., banking networks). The problem is especially acute in the design of many reactive systems which must exhibit correct ongoing behavior, yet are not amenable to thorough testing due to their inherently nondeterministic nature. One useful approach for specifying and reasoning about correctness of such systems is temporal logic model checking, which can provide an efficient and expressive tool for automatic verification that a finite state system meets a correctness specification formulated in temporal logic. We describe model checking algorithms and discuss their application. To do this, we focus attention on a particularly important type of temporal logic known as the Mucalculus.
Formal Specification: a Roadmap
, 2000
"... Formal specifications have been a focus of software engineering research for many years and have been applied in a wide variety of settings. Their industrial use is still limited but has been steadily growing. After recalling the essence, role, usage, and pitfalls of formal specification, the pa ..."
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Cited by 35 (0 self)
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Formal specifications have been a focus of software engineering research for many years and have been applied in a wide variety of settings. Their industrial use is still limited but has been steadily growing. After recalling the essence, role, usage, and pitfalls of formal specification, the paper reviews the main specification paradigms to date and discuss their evaluation criteria. It then provides a brief assessment of the current strengths and weaknesses of today's formal specification technology. This provides a basis for formulating a number of requirements for formal specification to become a core software engineering activity in the future.
Formal Methods for the Specification and Design of RealTime Safety Critical Systems
, 1992
"... Safety critical computers increasingly a#ect nearly every aspect of our lives. Computers control the planes we #y on, monitor our health in hospitals and do our work in hazardous environments. Computers with software de#ciencies that fail to meet stringent timing constraints have resulted in cat ..."
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Cited by 34 (0 self)
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Safety critical computers increasingly a#ect nearly every aspect of our lives. Computers control the planes we #y on, monitor our health in hospitals and do our work in hazardous environments. Computers with software de#ciencies that fail to meet stringent timing constraints have resulted in catastrophic failures. This paper surveys formal methods for specifying, designing and verifying realtime systems, so as to improve their safety and reliability. # To appear in Journal of Systems and Software,Vol. 18, Number 1, pages 33#60, April 1992. Jonathan Ostro# is with the Department of Computer Science, York University 4700 Keele Street, North York, Ontario, Canada, M3J 1P3. This work is supported by the Natural Sciences and Engineering Research Council of Canada. 1 CONTENTS 2 Contents 1 Introduction 3 2 De#ning the terms 6 2.1 Major issues that formal theories must address ::::::: 13 3 RealTime Programming Languages 14 4 Structured Methods and#or Graphical Languages 15 4.1 Str...
Qualitative SpatioTemporal Representation and Reasoning: A Computational Perspective
 Exploring Artifitial Intelligence in the New Millenium
, 2001
"... this paper argues for the rich world of representation that lies between these two extremes." Levesque and Brachman (1985) 1 Introduction Time and space belong to those few fundamental concepts that always puzzled scholars from almost all scientific disciplines, gave endless themes to science ..."
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Cited by 34 (12 self)
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this paper argues for the rich world of representation that lies between these two extremes." Levesque and Brachman (1985) 1 Introduction Time and space belong to those few fundamental concepts that always puzzled scholars from almost all scientific disciplines, gave endless themes to science fiction writers, and were of vital concern to our everyday life and commonsense reasoning. So whatever approach to AI one takes [ Russell and Norvig, 1995 ] , temporal and spatial representation and reasoning will always be among its most important ingredients (cf. [ Hayes, 1985 ] ). Knowledge representation (KR) has been quite successful in dealing separately with both time and space. The spectrum of formalisms in use ranges from relatively simple temporal and spatial databases, in which data are indexed by temporal and/or spatial parameters (see e.g. [ Srefik, 1995; Worboys, 1995 ] ), to much more sophisticated numerical methods developed in computational geom