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Design of Embedded Systems: Formal Models, Validation, and Synthesis
 PROCEEDINGS OF THE IEEE
, 1999
"... This paper addresses the design of reactive realtime embedded systems. Such systems are often heterogeneous in implementation technologies and design styles, for example by combining hardware ASICs with embedded software. The concurrent design process for such embedded systems involves solving the ..."
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Cited by 109 (9 self)
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This paper addresses the design of reactive realtime embedded systems. Such systems are often heterogeneous in implementation technologies and design styles, for example by combining hardware ASICs with embedded software. The concurrent design process for such embedded systems involves solving the specification, validation, and synthesis problems. We review the variety of approaches to these problems that have been taken.
Strong Termination of Logic Programs
, 1993
"... this paper appeared as [B]. 1. INTRODUCTION Termination of logic programs is of course of utmost importance. The question whether the topdown evaluation of a goal G terminates with respect to a logic program P is actually underspecified, given the fact that this evaluation may depend on the selecti ..."
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Cited by 51 (1 self)
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this paper appeared as [B]. 1. INTRODUCTION Termination of logic programs is of course of utmost importance. The question whether the topdown evaluation of a goal G terminates with respect to a logic program P is actually underspecified, given the fact that this evaluation may depend on the selection of atoms from goals and on the choice of the program clauses. In this paper termination is considered in the strong sense, i.e. irrespective of the selection of atoms in the goal and of the choice of the program clauses. This is the most demanding notion of termination. Less demanding approaches are: (1) termination for a fixed selection rule and for any choice of program clauses; (2) termination for some selection rule, depending on P, G and annotations on G, and for any choice of program clauses. All approaches can be weakened by requiring termination not for any but only for some
A Process Algebraic View of Linda Coordination Primitives
, 1998
"... The main Linda coordination primitives (asynchronous communication, read operation, nonblocking in/rd predicates) are studied in a process algebraic setting. A lattice of eight languages is proposed, where its bottom element L is a process algebra differing from CCS only for the asynchrony of the ou ..."
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Cited by 43 (14 self)
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The main Linda coordination primitives (asynchronous communication, read operation, nonblocking in/rd predicates) are studied in a process algebraic setting. A lattice of eight languages is proposed, where its bottom element L is a process algebra differing from CCS only for the asynchrony of the output operation, while all the other languages in the lattice are obtained as extension of this basic language by adding some of the Linda coordination primitives. The observational semantics for these languages are all obtained as the coarsest congruences contained in the barbed semantics, where only tuples are observable. The lattice of the eight languages collapses to a smaller fourpoints lattice of different bisimulationbased semantics. Notably, for L this semantics is the standard notion of strong bisimulation, where inputs and outputs/tuples are treated symmetrically. Keywords: Coordination languages, Semantics of Linda, Process algebra. 1 Introduction The aim of this paper is to pr...
On the Expressive Power of a Language for Programming Coordination Media
 In Proceedings of the 1998 ACM Symposium on Applied Computing (SACâ€™98
, 1998
"... A programmable coordination medium is a shared communication device whose behaviour can be defined by means of a suitable programming language according to the global system needs. This notion has indeed an impact over the design of multicomponent software system, since (part of) the system computa ..."
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Cited by 35 (24 self)
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A programmable coordination medium is a shared communication device whose behaviour can be defined by means of a suitable programming language according to the global system needs. This notion has indeed an impact over the design of multicomponent software system, since (part of) the system computational charge of can be in principle shifted from the communicating components (agents) to the communication device. At the same time, this raises the issue of the computational power of a programmable coordination medium, and of its expressiveness. As a meaningful example, this paper discusses the case of ReSpecT, the firstorder logic language used by the ACLT coordination model to define the behaviour of its multiple programmable logic tuple spaces, called tuple centres. Its expressiveness is discussed first by comparing ReSpecT with Petri Nets, taken as a reference model for the specification and design of concurrent and distributed systems, then by presenting some simple cases of coor...
On the Expressiveness of Linda Coordination Primitives
 Information and Computation
"... We introduce a process algebra containing the coordination primitives of Linda (asynchronous communication via a shared data space, read operation, nonblocking test operators on the shared space). We compare two possible semantics for the output operation: the former, that we call ordered, defines ..."
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Cited by 23 (11 self)
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We introduce a process algebra containing the coordination primitives of Linda (asynchronous communication via a shared data space, read operation, nonblocking test operators on the shared space). We compare two possible semantics for the output operation: the former, that we call ordered, defines the output as an operation that returns when the message has reached the shared data space; the latter, that we call unordered, returns just after sending the message to the tuple space. The process algebra under the ordered semantics is Turing powerful, as we are able to program any Random Access Machine. The main result of the paper is that the process algebra under the unordered semantics is not Turing powerful. This result is achieved by resorting to a net semantics in terms of contextual nets (P/T nets with inhibitor and read arcs), and showing that there exists a deadlockpreserving simulation of such nets by finite P/T nets, a formalism where termination is decidable. 1 Introduction ...
A model of computation for Fourier optical processors
 Optics in Computing 2000, Proc. SPIE
"... We present a novel and simple theoretical model of computation that captures what we believe are the most important characteristics of an optical Fourier transform processor. We use this abstract model to reason about the computational properties of the physical systems it describes. We define a gra ..."
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Cited by 17 (7 self)
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We present a novel and simple theoretical model of computation that captures what we believe are the most important characteristics of an optical Fourier transform processor. We use this abstract model to reason about the computational properties of the physical systems it describes. We define a grammar for our model's instruction language, and use it to write algorithms for wellknown filtering and correlation techniques. We also suggest suitable computational complexity measures that could be used to analyze any coherent optical information processing technique, described with the language, for efficiency. Our choice of instruction language allows us to argue that algorithms describable with this model should have optical implementations that do not require a digital electronic computer to act as a master unit. Through simulation of a well known model of computation from computer theory we investigate the generalpurpose capabilities of analog optical processors.
Comparing Three Semantics for Lindalike Languages
 Theoretical Computer Science
"... A simple calculus based on generative communication is introduced; among its primitives, it contains a conditional input operation that tests for presence (or absence) of an output, reminiscent of the inp predicate of Linda. We study three different semantics for the output operation, called instant ..."
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Cited by 16 (6 self)
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A simple calculus based on generative communication is introduced; among its primitives, it contains a conditional input operation that tests for presence (or absence) of an output, reminiscent of the inp predicate of Linda. We study three different semantics for the output operation, called instantaneous, ordered and unordered, and we compare these approaches from two different points of view. First, we investigate the associated behavioural semantics by characterizing the coarsest congruence contained in the barbed bisimulation. We obtain the following results: in the instantaneous case the coarsest congruence is a variant of asynchronous bisimulation while, for the ordered and unordered semantics, we obtain a small variant of the classic (synchronous) bisimulation. Moreover, the three obtained congruences are pairwise different. Then, we compare the expressiveness of the three approaches. We first list a class of coordination primitives that are directly implementable in our calcul...
On the Expressiveness and Decidability of HigherOrder Process Calculi
, 2008
"... In higherorder process calculi the values exchanged in communications may contain processes. A core calculus of higherorder concurrency is studied; it has only the operators necessary to express higherorder communications: input prefix, process output, and parallel composition. By exhibiting a ne ..."
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Cited by 12 (5 self)
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In higherorder process calculi the values exchanged in communications may contain processes. A core calculus of higherorder concurrency is studied; it has only the operators necessary to express higherorder communications: input prefix, process output, and parallel composition. By exhibiting a nearly deterministic encoding of Minsky Machines, the calculus is shown to be Turing Complete and therefore its termination problem is undecidable. Strong bisimilarity, however, is proved to be decidable. Further, the main forms of strong bisimilarity for higherorder processes (higherorder bisimilarity, context bisimilarity, normal bisimilarity, barbed congruence) coincide. They also coincide with their asynchronous versions. A sound and complete axiomatization of bisimilarity is given. Finally, bisimilarity is shown to become undecidable if at least four static (i.e., toplevel) restrictions are added to the calculus.
Continuousspace model of computation is Turing universal
 Critical Technologies for the Future of Computing, Proceedings of SPIE vol. 4109
, 2000
"... Our model of computation (theoretical machine) was designed for the analysis of analog Fourier optical processors, its basic data unit being a continuous image of unbounded resolution. In this paper, we demonstrate the universality of our machine by presenting a framework for arbitrary Turing machin ..."
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Cited by 11 (4 self)
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Our model of computation (theoretical machine) was designed for the analysis of analog Fourier optical processors, its basic data unit being a continuous image of unbounded resolution. In this paper, we demonstrate the universality of our machine by presenting a framework for arbitrary Turing machine simulation. Computational complexity benets are also demonstrated by providing a O(log 2 n) algorithm for a search problem that has a lower bound of n 1 on a Turing machine.