Showing papers by "Jan A. Bergstra published in 2003"
30 Jun 2003
TL;DR: The basic polarized process algebra is completed yielding as a projective limit a cpo which also comprises infinite processes and it is shown that this model serves in a natural way as a semantics for several program algebras.
Abstract: The basic polarized process algebra is completed yielding as a projective limit a cpo which also comprises infinite processes. It is shown that this model serves in a natural way as a semantics for several program algebras. In particular, the fully abstract model of the program algebra axioms of [2] is considered which results by working modulo behavioral congruence. This algebra is extended with a new basic instruction, named 'entry instruction' and denoted with '@'. Addition of @ allows many more equations and conditional equations to be stated. It becomes possible to find an axiomatization of program inequality. Technically this axiomatization is an infinite final algebra specification using conditional equations and auxiliary objects.
83 citations
01 Jan 2003
TL;DR: A process algebra obtained by extending a combination of the process algebra with continuous relative timing from Baeten and Middelburg has rules to derive equations with the help of real analysis and makes it possible to deal with the behaviour of hybrid systems.
Abstract: We propose a process algebra obtained by extending a combination
of the process algebra with continuous relative timing from Baeten
and Middelburg [Process Algebra with Timing, Springer, Chap. 4, 2002]
and the process algebra with propositional signals from Baeten and
Bergstra [Theoretical Computer Science 177:381–405, 1997]. The proposed
process algebra makes it possible to deal with the behaviour of
hybrid systems, i.e. systems in which the instantaneous state transitions
caused by performing actions are alternated with continuous state evolutions.
This process algebra has, in addition to equational axioms, rules
to derive equations with the help of real analysis.
8 citations
01 Jan 2003
TL;DR: In this paper, the authors propose a process algebra obtained by adapting the process algebra with continuous relative timing from Baeten and Middelburg [Process Algebra with Timing, Springer, Chap. 4, 2002] to spatially located actions.
Abstract: . We propose a process algebra obtained by adapting the process algebra with continuous relative timing from Baeten and Middelburg [Process Algebra with Timing, Springer, Chap. 4, 2002] to spatially located actions. This process algebra makes it possible to deal with the behaviour of systems with a known time-dependent spatial distribution, such as a protocol transmitting data via a mobile intermediate station. It is a reformulation of the real space process algebra from Baeten and Bergstra [Formal Aspects of Computing 5:481{529, 1993] in a setting with urgent actions. This leads to many simplifications. Keywords: process algebra, continuous relative timing, spatially located actions, distributed systems, state operator, maximal progress, asynchronous communication, urgent actions. 1998 CR Categories: C.2.4, D.2.1, D.2.4, F.1.2, F.3.1.
2 citations
TL;DR: The definition and notations are based on the program algebra PGA: a small body of theory allowing one to reason fundamentally and practically about programs viewed as instruction sequences.
Abstract: We define a notion of program which is not a computer program but an operator program : a detailed description of actions performed and decisions taken by a human operator (computer user) performing a task to achieve a goal in a simple setting consisting of that user, one or more computers and a work environment. Our definition and notations are based on the program algebra PGA: a small body of theory allowing one to reason fundamentally and practically about programs viewed as instruction sequences. This article is entirely self-contained and introduces all concepts and notations used. We offer some small examples, and we sketch one limitation of our approach.
2 citations
TL;DR: In this paper, a process algebra obtained by adapting the process algebra with continuous relative timing from Baeten and Middelburg [Process Algebra with Timing, Springer, 2002, Chap. 4] to spatially located actions is presented.
Abstract: We propose a process algebra obtained by adapting the process algebra with continuous relative timing from Baeten and Middelburg [Process Algebra with Timing, Springer, 2002, Chap. 4] to spatially located actions. This process algebra makes it possible to deal with the behaviour of systems with a known time-dependent spatial distribution, such as protocols transmitting data via a mobile intermediate station. It is a reformulation of the real space process algebra from Baeten and Bergstra [Formal Aspects of Computing, 5, 1993, 481-529] in a setting with urgent actions. This leads to many simplifications.
2 citations
01 Jan 2003
TL;DR: The orthogonal bisimulation equivalence as discussed by the authors is a congruence for ACP extended with abstraction and priority operators, and it can be seen as an extension of ACP with priority operators.
Abstract: We propose a re1nement of branchingbisimulation equivalence that we call orthog onal bisimulation equivalence. Typically, internal activity (the performance of � -steps) may be compressed, but not completely discarded. Hence, a process with � -steps cannot be equivalent to one without � -steps. Also, we present a modal characterization of orthogonal bisimulation equivalence. This equivalence is a congruence for ACP extended with abstraction and priority operators. We provide a complete axiomatization, and describe some expressiveness results. Finally, we present the veri1cation of a PAR protocol that is speci1ed with use of priorities. c 2003 Published by Elsevier B.V.
1 citations
04 Nov 2003
TL;DR: In this article, a control code algebra (CCA) based on machine functions has been developed for just-in-time (JIT) compilation, which is used to formalize the well-known compiler fixed point, the managed execution of JIT compiled text and the concept of a verifying compiler.
Abstract: Machine functions have been introduced by Earley and Sturgis in [6] in order to provide a mathematical foundation of the use of the T-diagrams proposed by Bratman in [5]. Machine functions describe the operation of a machine at a very abstract level. A theory of hardware and software based on machine functions may be called a machine function theory, or alternatively when focusing on inputs and outputs for machine functions a control code algebra (CCA). In this paper we develop some control code algebras from first principles. Machine function types are designed specifically for various application such as program compilation, assembly, interpretation, managed interpretation and just-in-time compilation. Machine function dependent CCA’s are used to formalize the well-known compiler fixed point, the managed execution of JIT compiled text and the concept of a verifying compiler.