Results 1  10
of
21
Practical Applications of Constraint Programming
 CONSTRAINTS
, 1996
"... Constraint programming is newly flowering in industry. Several companies have recently started up to exploit the technology, and the number of industrial applications is now growing very quickly. This survey will seek, by examples, ..."
Abstract

Cited by 105 (1 self)
 Add to MetaCart
Constraint programming is newly flowering in industry. Several companies have recently started up to exploit the technology, and the number of industrial applications is now growing very quickly. This survey will seek, by examples,
Temporal Concurrent Constraint Programming: Denotation, Logic and Applications
, 2002
"... The tcc model is a formalism for reactive concurrent constraint programming. We present a model of temporal concurrent constraint programming which adds to tcc the capability of modeling asynchronous and nondeterministic timed behavior. We call this tcc extension the ntcc calculus. We also give a d ..."
Abstract

Cited by 68 (24 self)
 Add to MetaCart
The tcc model is a formalism for reactive concurrent constraint programming. We present a model of temporal concurrent constraint programming which adds to tcc the capability of modeling asynchronous and nondeterministic timed behavior. We call this tcc extension the ntcc calculus. We also give a denotational semantics for the strongestpostcondition of ntcc processes and, based on this semantics, we develop a proof system for lineartemporal properties of these processes. The expressiveness of ntcc is illustrated by modeling cells, timed systems such as RCX controllers, multiagent systems such as the Predator /Prey game, and musical applications such as generation of rhythms patterns and controlled improvisation. 1
Timed Default Concurrent Constraint Programming
 Journal of Symbolic Computation
, 1996
"... Synchronous programming (Berry (1989)) is a powerful approach to programming reactive systems. Following the idea that "processes are relations extended over time" (Abramsky (1993)), we propose a simple but powerful model for timed, determinate computation, extending the closureoperator model for u ..."
Abstract

Cited by 62 (11 self)
 Add to MetaCart
Synchronous programming (Berry (1989)) is a powerful approach to programming reactive systems. Following the idea that "processes are relations extended over time" (Abramsky (1993)), we propose a simple but powerful model for timed, determinate computation, extending the closureoperator model for untimed concurrent constraint programming (CCP). In (Saraswat et al. 1994a) we had proposed a model for this called tcc here we extend the model of tcc to express strong timeouts: if an event A does not happen through time t, cause event B to happen at time t. Such constructs arise naturally in practice (e.g. in modeling transistors) and are supported in synchronous programming languages. The fundamental conceptual difficulty posed by these operations is that they are nonmonotonic. We provide a compositional semantics to the nonmonotonic version of concurrent constraint programming (Default cc) obtained by changing the underlying logic from intuitionistic logic to Reiter's default logic...
On the Expressive Power of Concurrent Constraint Programming Languages
 IN PPDP 2002
, 2002
"... The tcc paradigm is a formalism for timed concurrent constraint programming. Several tcc languages di#ering in their way of expressing infinite behavior have been proposed in the literature. In this paper ..."
Abstract

Cited by 15 (15 self)
 Add to MetaCart
The tcc paradigm is a formalism for timed concurrent constraint programming. Several tcc languages di#ering in their way of expressing infinite behavior have been proposed in the literature. In this paper
On the Expressiveness of Timed Concurrent Constraint Programming
 Electronics Notes in Theoretical Computer Science
, 1999
"... We prove that both the synchronous data flow language Lustre restricted to finite value types and the synchronous state oriented language Argos are embedded in the synchronous paradigm Timed Concurrent Constraint (tcc). In fact, for each of the two languages we provide a tcc language encoding it com ..."
Abstract

Cited by 13 (2 self)
 Add to MetaCart
We prove that both the synchronous data flow language Lustre restricted to finite value types and the synchronous state oriented language Argos are embedded in the synchronous paradigm Timed Concurrent Constraint (tcc). In fact, for each of the two languages we provide a tcc language encoding it compositionally w.r.to the structure of programs. Moreover, we prove that the "strong abortion" mechanism of the synchronous imperative language Esterel can be encoded in tcc. 1
Specification and Verification of ConstraintBased Dynamic Systems
 Principles and Practice of Constraint Programming, number 874 in LNCS
"... . Constraint satisfaction can be seen as a dynamic process that approaches the solution set of the given constraints asymptotically [6]. Constraint programming is seen as creating a dynamic system with the required property. We have developed a semantic model for dynamic systems, Constraint Nets ..."
Abstract

Cited by 12 (7 self)
 Add to MetaCart
. Constraint satisfaction can be seen as a dynamic process that approaches the solution set of the given constraints asymptotically [6]. Constraint programming is seen as creating a dynamic system with the required property. We have developed a semantic model for dynamic systems, Constraint Nets, which serves as a useful abstract target machine for constraint programming languages, providing both semantics and pragmatics. Generalizing, here we view a constraintbased dynamic system as a dynamic system which approaches the solution set of the given constraints persistently. Most robotic systems are constraintbased dynamic systems with tasks specified as constraints. In this paper, we further explore the specification and verification of constraintbased dynamic systems. We first develop generalized 8automata for the specification and verification of general (hybrid) dynamic systems, then explicate the relationship between constraintbased dynamic systems and their require...
On the Expressive Power of Temporal Concurrent Constraint Programming Languages
 In Proceedings of the 4th ACM SIGPLAN International Conference on Principles and Practice of Declarative Programming
, 2002
"... The tcc paradigm is a formalism for timed concurrent constraint programming. Several tcc languages differing in their way of expressing infinite behavior have been proposed in the literature. In this paper we study the expressive power of some of these languages. In particular, we show that (1) recu ..."
Abstract

Cited by 10 (1 self)
 Add to MetaCart
The tcc paradigm is a formalism for timed concurrent constraint programming. Several tcc languages differing in their way of expressing infinite behavior have been proposed in the literature. In this paper we study the expressive power of some of these languages. In particular, we show that (1) recursion using procedures with parameters is behaviorally equivalent to parameterless procedures with dynamic scoping, that (2) replication is behaviorally equivalent to parameterless procedures with static scoping, and that (3) the languages from (1) are strictly more expressive than the languages from (2). Furthermore, we show that behavioral equivalence is undecidable for the languages from (1), but decidable for the languages from (2). Both undecidability results hold even if the process variables take values from a fixed finite domain.
On Timed Coordination Languages
 Fourth International Conference on Coordination Models and Languages, LNCS 1906
, 2000
"... . Although very simple and elegant, Lindastyle coordination models lack the notion of time, and are therefore not able to precisely model reallife coordination applications, featuring timeouts and soft realtime constraints. This paper aims at introducing time in these models. To that end, we ..."
Abstract

Cited by 8 (0 self)
 Add to MetaCart
. Although very simple and elegant, Lindastyle coordination models lack the notion of time, and are therefore not able to precisely model reallife coordination applications, featuring timeouts and soft realtime constraints. This paper aims at introducing time in these models. To that end, we consider two notions of time, relative time and absolute time, and, for each notion, two types of features. On the one hand, with respect to relative time, we describe two extensions: (i) a delay mechanism to postpone the execution of communication primitives, and (ii) explicit deadlines on the validity of tuples and on the duration of suspension of communication operations. On the other hand, for absolute time, we introduce: (iii) a wait primitive capable of waiting till an absolute point of time, and (iv) time intervals, both on tuples in the data store and on communication operations. The resulting four coordination models are analyzed and compared both from the semantics viewp...
Default Timed Concurrent Constraint Programming (Extended Abstract)
, 1995
"... We extend the model of [SJG94b] to express strong timeouts (and preemption): if an event A does not happen through time t, cause event B to happen at time t. Such constructs arise naturally in practice (e.g. in modeling transistors) and are supported in languages such as Esterel (through instanta ..."
Abstract

Cited by 8 (1 self)
 Add to MetaCart
We extend the model of [SJG94b] to express strong timeouts (and preemption): if an event A does not happen through time t, cause event B to happen at time t. Such constructs arise naturally in practice (e.g. in modeling transistors) and are supported in languages such as Esterel (through instantaneous watchdogs) and Lustre (through the "current" operator). The fundamental conceptual difficulty posed by these operators is that they are nonmonotonic. We provide a simple compositional semantics to the nonmonotonic version of concurrent constraint programming (CCP) obtained by changing the underlying logic from intuitionistic logic to Reiter 's default logic [Rei80]. This allows us to use the same construction (uniform extension through time) to develop Default Timed CCP (Default tcc) as we had used to develop Timed CCP (tcc) from CCP [SJG94b]. Indeed the smooth embedding of CCP processes into Default cc processes lifts to a smooth embedding of tcc processes into Default t...
Models for Concurrent Constraint Programming
 CONCUR ’96: Concurrency Theory, 7th International Conference, volume 1119 of Lecture Notes in Computer Science
, 1996
"... . Concurrent constraint programming is a simple but powerful framework for computation based on four basic computational ideas: concurrency (multiple agents are simultaneously active), communication (they interact via the monotonic accumulation of constraints on shared variables), coordination (the ..."
Abstract

Cited by 6 (0 self)
 Add to MetaCart
. Concurrent constraint programming is a simple but powerful framework for computation based on four basic computational ideas: concurrency (multiple agents are simultaneously active), communication (they interact via the monotonic accumulation of constraints on shared variables), coordination (the presence or absence of information can guard evolution of an agent), and localization (each agent has access to only a finite, though dynamically varying, number of variables, and can create new variables on the fly). Unlike other foundational models of concurrency such as CCS, CSP, Petri nets and the ßcalculus, such flexibility is already made available within the context of determinate computation. This allows the development of a rich and tractable theory of concurrent processes within the context of which additional computational notion such as indeterminacy, reactivity, instantaneous interrupts and continuous (densetime) autonomous evolution have been developed. We survey the develop...