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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 63 (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
Efficient OntheFly Model Checking for CTL
, 1995
"... This paper gives an onthefly algorithm for determining whether a finitestate system satisfies a formula in the temporal logic CTL*. The time complexity of our algorithm matches that of the best existing "global algorithm" for model checking in this logic, and it performs as well as the best known ..."
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Cited by 50 (5 self)
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This paper gives an onthefly algorithm for determining whether a finitestate system satisfies a formula in the temporal logic CTL*. The time complexity of our algorithm matches that of the best existing "global algorithm" for model checking in this logic, and it performs as well as the best known global algorithms for the sublogics CTL and LTL. In contrast with these approaches, however, our routine constructs the state space of the system under consideration in a needdriven fashion and will therefore perform better in practice.
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...
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 41 (30 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 39 (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., banking n ..."
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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 34 (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.
The Complexity of Temporal Logic Model Checking
, 2002
"... Temporal logic. Logical formalisms for reasoning about time and the timing of events appear in several fields: physics, philosophy, linguistics, etc. Not surprisingly, they also appear in computer science, a field where logic is ubiquitous. Here temporal logics are used in automated reasoning, in pl ..."
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Cited by 32 (0 self)
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Temporal logic. Logical formalisms for reasoning about time and the timing of events appear in several fields: physics, philosophy, linguistics, etc. Not surprisingly, they also appear in computer science, a field where logic is ubiquitous. Here temporal logics are used in automated reasoning, in planning, in semantics of programming languages, in artificial intelligence, etc. There is one area of computer science where temporal logic has been unusually successful: the specification and verification of programs and systems, an area we shall just call programming for simplicity. In today's curricula, thousands of programmers first learn about temporal logic in a course on model checking!
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 31 (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...
Characterizing EF and EX tree logics
 In CONCUR 2004
"... We describe the expressive power of temporal branching time logics that use the modalities EX and EF. We give a forbidden pattern characterization of the tree languages definable in three logics: EX, EF and EX+EF. The properties in these characterizations can be verified in polynomial time when give ..."
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Cited by 31 (8 self)
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We describe the expressive power of temporal branching time logics that use the modalities EX and EF. We give a forbidden pattern characterization of the tree languages definable in three logics: EX, EF and EX+EF. The properties in these characterizations can be verified in polynomial time when given a minimal deterministic bottomup tree automaton. We consider the definability problem for logics over binary trees: given a regular tree language decide if it can be expressed by a formula of the logic in question. The main motivation for considering this problem is to understand the expressive power of tree logics. Although a very old question, definability has gained new relevance with the XML community’s burgeoning interest in tree models [8]. Indeed, numerous new formalisms for describing tree properties have been recently proposed.