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21
Detecting Deadlocks In Concurrent Systems
 IN CONCUR’98: CONCURRENCY THEORY (NICE
, 1998
"... We study deadlocks using geometric methods based on generalized process graphs [11], i.e., cubical complexes or HigherDimensional Automata (HDA) [23, 24, 30, 35], describing the semantics of the concurrent system of interest. A new algorithm is described and fully assessed, both theoretically a ..."
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Cited by 47 (11 self)
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We study deadlocks using geometric methods based on generalized process graphs [11], i.e., cubical complexes or HigherDimensional Automata (HDA) [23, 24, 30, 35], describing the semantics of the concurrent system of interest. A new algorithm is described and fully assessed, both theoretically and practically and compared with more wellknown traversing techniques. An implementation is
Algebraic Topology And Concurrency
 Theoretical Computer Science
, 1998
"... This article is intended to provide some new insights about concurrency theory using ideas from geometry, and more specifically from algebraic topology. The aim of the paper is twofold: we justify applications of geometrical methods in concurrency through some chosen examples and we give the mathem ..."
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Cited by 43 (10 self)
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This article is intended to provide some new insights about concurrency theory using ideas from geometry, and more specifically from algebraic topology. The aim of the paper is twofold: we justify applications of geometrical methods in concurrency through some chosen examples and we give the mathematical foundations needed to understand the geometric phenomenon that we identify. In particular we show that the usual notion of homotopy has to be refined to take into account some partial ordering describing the way time goes. This gives rise to some new interesting mathematical problems as well as give some common grounds to computerscientific problems that have not been precisely related otherwise in the past. The organization of the paper is as follows. In Section 2 we explain to which extent we can use some geometrical ideas in computer science: we list a few of the potential or well known areas of application and try to exemplify some of the properties of concurrent (and distributed) systems we are interested in. We first explain the interest of using some geometric ideas for semantical reasons. Then we take the example of concurrent databases with the problem of finding deadlocks and with some aspects of serializability theory. More general questions about schedules can be asked as well and related to some geometric considerations, even for scheduling microinstructions (and not only coarsegrained transactions as for databases). The final example is the one of faulttolerant protocols for distributed systems, where subtle scheduling properties go into play. In Section 3 we give the first few definitions needed for modeling the topological spaces arising from Section 2. Basically, we need to define a topological space containing all traces of executions of the concu...
Refining Model Checking by Abstract Interpretation
 Automated Software Engineering
, 1999
"... In abstract modelchecking, the semantics of an infinite transition system is abstracted to get a finite approximation on which temporallogic/mucalculus modelchecking can be directly applied. The paper proposes two improvements of abstract modelchecking which can be applied to infinite abstract ..."
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Cited by 35 (4 self)
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In abstract modelchecking, the semantics of an infinite transition system is abstracted to get a finite approximation on which temporallogic/mucalculus modelchecking can be directly applied. The paper proposes two improvements of abstract modelchecking which can be applied to infinite abstract transition systems:  A new combination of forwards and backwards abstract fixedpoint modelchecking computations for universal safety. It computes a more precise result than that computed by conjunction of the forward and backward analyses alone, without needing to refine the abstraction;  When abstraction is unsound (as can happen in minimum/maximum pathlength problems), it is proposed to use the partial results of a classical combination of forward and backward abstract interpretation analyses for universal safety in order to reduce, onthefly, the concrete state space to be searched by modelchecking.
Abstract interpretation based formal methods and future challenges, invited paper
 Informatics — 10 Years Back, 10 Years Ahead, volume 2000 of Lecture Notes in Computer Science
, 2001
"... Abstract. In order to contribute to the solution of the software reliability problem, tools have been designed to analyze statically the runtime behavior of programs. Because the correctness problem is undecidable, some form of approximation is needed. The purpose of abstract interpretation is to f ..."
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Cited by 33 (6 self)
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Abstract. In order to contribute to the solution of the software reliability problem, tools have been designed to analyze statically the runtime behavior of programs. Because the correctness problem is undecidable, some form of approximation is needed. The purpose of abstract interpretation is to formalize this idea of approximation. We illustrate informally the application of abstraction to the semantics of programming languages as well as to static program analysis. The main point is that in order to reason or compute about a complex system, some information must be lost, that is the observation of executions must be either partial or at a high level of abstraction. In the second part of the paper, we compare static program analysis with deductive methods, modelchecking and type inference. Their foundational ideas are briefly reviewed, and the shortcomings of these four methods are discussed, including when they should be combined. Alternatively, since program debugging is still the main program verification
Geometry and Concurrency: A User's Guide
, 2000
"... Introduction "Geometry and Concurrency" is not yet a wellestablished domain of research, but is rather made of a collection of seemingly related techniques, algorithms and formalizations, coming from different application areas, accumulated over a long period of time. There is currently ..."
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Cited by 30 (7 self)
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Introduction "Geometry and Concurrency" is not yet a wellestablished domain of research, but is rather made of a collection of seemingly related techniques, algorithms and formalizations, coming from different application areas, accumulated over a long period of time. There is currently a certain amount of effort made for unifying these (in particular see the article (Gunawardena, 1994)), following the workshop "New Connections between Computer Science and Mathematics" held at the Newton Institute in Cambridge, England in November 1995 (and sponsored by HP/BRIMS). More recently, the first workshop on the very same subject has been held in Aalborg, Denmark (see http://www.math.auc.dk/~raussen/admin/workshop/workshop.html where the articles of this issue, among others, have been first sketched. But what is "Geometry and Concurrency" composed of then? It is an area of research made of techniques which use geometrical reasoning for describing and solving problems
Characterization of a Sequentially Consistent Memory and Verification of a Cache Memory by Abstraction
 Distributed Computing
, 1995
"... ion ? Susanne Graf VERIMAG ?? , Avenue de la Vignate, F38610 Gi`eres ? ? ? Abstract. The contribution of the paper is twofold. We give a set of properties expressible as temporal logic formulas such that any system satisfying them is a sequentially consistent memory, and which is sufficiently ..."
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Cited by 28 (4 self)
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ion ? Susanne Graf VERIMAG ?? , Avenue de la Vignate, F38610 Gi`eres ? ? ? Abstract. The contribution of the paper is twofold. We give a set of properties expressible as temporal logic formulas such that any system satisfying them is a sequentially consistent memory, and which is sufficiently precise such that every reasonable concrete system that implements a sequentially consistent memory satisfies these properties. Then, we verify these properties on a distributed cache memory system by means of a verification method, based on the use of abstract interpretation which has been presented in previous papers and so far applied to finite state systems. The motivation for this paper was to show that it can also be successfully applied to systems with an infinite state space. This is a revised and extended version of [Gra94]. 1 Introduction We propose to verify the distributed cache memory presented in [ABM93] and [Ger94] by using the verification method proposed in [BBLS92,LGS +...
Verifying a Distributed Database Lookup Manager Written in Erlang
, 1999
"... We describe a casestudy in which formal methods were used to verify an important responsiveness property of a distributed database system which is used heavily at Ericsson in a number of recent products. One of the aims of the project was to verify the actual running code which is written in ..."
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Cited by 18 (8 self)
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We describe a casestudy in which formal methods were used to verify an important responsiveness property of a distributed database system which is used heavily at Ericsson in a number of recent products. One of the aims of the project was to verify the actual running code which is written in the distributed functional language Erlang. In a joint project between SICS and Ericsson we have over the past few years been developing a tableaubased verication tool for Erlang of considerable scope. In particular, we are capable of addressing  on the level of running program code  systems with unbounded behaviour along the many dimensions in which this happens in "real" programs, involving datatypes, recursive control structures, error handling and recovery, initialisation, and dynamic process creation. The database lookup manager considered here contains most of these features, giving rise to innite state behaviour which is not very adequately handled using model checking o...
On the Expressiveness of higher dimensional automata
 EXPRESS 2004, ENTCS
, 2005
"... Abstract In this paper I compare the expressive power of several models of concurrency based on their ability to represent causal dependence. To this end, I translate these models, in behaviour preserving ways, into the model of higher dimensional automata, which is the most expressive model under i ..."
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Abstract In this paper I compare the expressive power of several models of concurrency based on their ability to represent causal dependence. To this end, I translate these models, in behaviour preserving ways, into the model of higher dimensional automata, which is the most expressive model under investigation. In particular, I propose four different translations of Petri nets, corresponding to the four different computational interpretations of nets found in the literature. I also extend various equivalence relations for concurrent systems to higher dimensional automata. These include the history preserving bisimulation, which is the coarsest equivalence that fully respects branching time, causality and their interplay, as well as the STbisimulation, a branching time respecting equivalence that takes causality into account to the extent that it is expressible by actions overlapping in time. Through their embeddings in higher dimensional automata, it is now welldefined whether members of different models of concurrency are equivalent.
Implementing a Static Analyzer of Concurrent Programs: Problems and Perspectives
, 1996
"... . The aim of the paper is to share the design problems we experienced when we were implementing a prototype analyzer of an asynchronous concurrent language. This new kind of static analyzer is based on previous work about operational semantics of parallel languages that can express concurrency and n ..."
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Cited by 15 (0 self)
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. The aim of the paper is to share the design problems we experienced when we were implementing a prototype analyzer of an asynchronous concurrent language. This new kind of static analyzer is based on previous work about operational semantics of parallel languages that can express concurrency and nondeterminism of actions: it constructs abstract automata reflecting all the possible execution behaviours of programs written in languages such as Parallel Pascal [Cri95] or Concurrent ML [Cri96]. We will also present some experimental results dealing with the size of the generated automata and the precision of the analysis. For instance some wellknown mutual exclusion protocols have been automatically proven correct. The analyzer has been interfaced using the HTML markup language: this allows the user to ask for computed invariants at given program points. 1 Introduction 1.1 Motivation Abstract interpretation is aimed at producing tools that automatically produce invariant properties o...
Program Analysis Position Statement: The Abstract Interpretation Perspective
, 1996
"... Interpretation Perspective Patrick Cousot Program Analysis Position Statement: ffl Semantic analysis (of programs, systems, etc.) should become a mature discipline to be included in educational curricula in computer science; ffl This requires the discipline to evolve from an illassorted collecti ..."
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Cited by 3 (0 self)
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Interpretation Perspective Patrick Cousot Program Analysis Position Statement: ffl Semantic analysis (of programs, systems, etc.) should become a mature discipline to be included in educational curricula in computer science; ffl This requires the discipline to evolve from an illassorted collection of methods and algorithms to a large scope formal reasoning and design methodology; ffl In particular, program analysis methods should be explained in language, program encoding, semantics, property, property encoding, and approximation independent way, to be of very broad scope and wide usefulness; ffl This might be possible by reasoning on the approximation of the structures involved in semantical specifications; ffl This effort would culminate in a general theory of semantical approximation leading to a tractable composable parameterized semantical analysis design methodology; ffl From a more practical point of view, the methodology would be applied to the uniform design of: ...