LMNtal (pronounced "elemental") is a simple language model based on hierarchical graph rewriting that uses logical variables to represent connectivity and membranes to represent hierarchy. LMNtal is an outco...
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LMNtal (pronounced "elemental") is a simple language model based on hierarchical graph rewriting that uses logical variables to represent connectivity and membranes to represent hierarchy. LMNtal is an outcome of the attempt to unify constraint based concurrency and constraint Handling Rules (CHR), the two notable extensions to concurrent logic programming. LMNtal is intended to be a substrate language of various computational models, especially those addressing concurrency, mobility and multiset rewriting. Although the principal objective of LMNtal was to provide a unifying computational model, it is of interest to equip the formalism with a precise logical interpretation. In this paper, we show that it is possible to give LMNtal a simple logical interpretation based on intuitionistic linear logic and a flattening technique. This enables us to call LMNtal a hierarchical, concurrent linear logic language. (C) 2009 Elsevier B.V. All rights reserved.
constraint Handling Rules (CHR) is both an effective concurrent declarative programming language and a versatile computational logic formalism. In CHR, guarded reactive rules rewrite a multi-set of constraints. Concur...
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constraint Handling Rules (CHR) is both an effective concurrent declarative programming language and a versatile computational logic formalism. In CHR, guarded reactive rules rewrite a multi-set of constraints. Concurrency is inherent, since rules can be applied to the constraints in parallel. In this comprehensive survey, we give an overview of the concurrent, parallel as well as distributed CHR semantics, standard and more exotic, that have been proposed over the years at various levels of refinement. These semantics range from the abstract to the concrete. They are related by formal soundness results. Their correctness is proven as a correspondence between parallel and sequential computations. On the more practical side, we present common concise example CHR programs that have been widely used in experiments and benchmarks. We review parallel and distributed CHR implementations in software as well as hardware. The experimental results obtained show a parallel speed-up for unmodified sequential CHR programs. The software implementations are available online for free download and we give the web links. Due to its high level of abstraction, the CHR formalism can also be used to implement and analyse models for concurrency. To this end, the Software Transaction Model, the Actor Model, Colored Petri Nets and the Join-Calculus have been faithfully encoded in CHR. Finally, we identify and discuss commonalities of the approaches surveyed and indicate what problems are left open for future research.
Spatial constraint systems are algebraic structures from concurrent constraint programming to specify spatial and epistemic behavior in multi-agent systems. In this paper spatial constraint systems are used to give an...
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Spatial constraint systems are algebraic structures from concurrent constraint programming to specify spatial and epistemic behavior in multi-agent systems. In this paper spatial constraint systems are used to give an abstract characterization of the notion of normality in modal logic and to derive right inverse/reverse operators for modal languages. In particular, a necessary and sufficient condition for the existence of right inverses is identified and the abstract notion of normality is shown to correspond to the preservation of finite suprema. Furthermore, a taxonomy of normal right inverses is provided, identifying the greatest normal right inverse as well as the complete family of minimal right inverses. These results are applied to existing modal languages such as the weakest normal modal logic, Hennessy-Milner logic, and linear-time temporal logic. Some implications of these results are also discussed in the context of modal concepts such as bisimilarity and inconsistency invariance. (C) 2018 Elsevier B.V. All rights reserved.
concurrent constraint programming (CCP) is a well-established model for concurrency that singles out the fundamental aspects of asynchronous systems whose agents (or processes) evolve by posting and querying (partial)...
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concurrent constraint programming (CCP) is a well-established model for concurrency that singles out the fundamental aspects of asynchronous systems whose agents (or processes) evolve by posting and querying (partial) information in a global medium. Bisimilarity is a standard behavioral equivalence in concurrency theory. However, only recently a well-behaved notion of bisimilarity for CCP, and a CCP partition refinement algorithm for deciding the strong version of this equivalence have been proposed. Weak bisimilarity is a central behavioral equivalence in process calculi and it is obtained from the strong case by taking into account only the actions that are observable in the system. Typically, the standard partition refinement can also be used for deciding weak bisimilarity simply by using Milner's reduction from weak to strong bisimilarity;a technique referred to as saturation. In this paper we demonstrate that, because of its involved labeled transitions, the above-mentioned saturation technique does not work for CCP. We give an alternative reduction from weak CCP bisimilarity to the strong one that allows us to use the CCP partition refinement algorithm for deciding this equivalence. (C) 2014 Elsevier B.V. All rights reserved.
Modelling musical structures is a research field prominent among mathematicians and computer scientists as well as musicologists, psychomusicologists and musicians. constraintprogramming has been proved to be a highl...
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Modelling musical structures is a research field prominent among mathematicians and computer scientists as well as musicologists, psychomusicologists and musicians. constraintprogramming has been proved to be a highly appropriate technique in this field. For the task of automated music composition, in particular, constraints have been shown to describe composition principles in a declarative, natural, and, above all, efficient way since music composition knowledge is in fact a collection of conditions rather than a sort of cookery-book. Unfortunately, many approaches stress the technical aspects of applying constraints and do not think about the concrete role of constraints, i.e. about what music really should be. In general, the composer as an artist is more concerned about what he wants to say through his music than with theoretically (or socially or psychologically) established rules. This means that automated music composition needs practical goals in order to make sense. The role of those goals as well as musical constraints and constraint technologies that help to realize the goals are to be shown in this article. As a modelling example the system COPPELIA is introduced. It generates music on the basis of the structures, goals, and contents of given multimedia presentations. In this relatively young field of constraint application that does not supply such ideal, well-defined and closed sets of conditions as technical applications do, we find it very important to also present general thoughts about the sense of our application, about the development of composition constraints and the conditions under which these constraints work effectively.
Most interactive scenarios are based on informal specifications, so that it is not possible to formally verify properties of such systems. We advocate the need for a general and formal model aiming at ensuring safe ex...
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Most interactive scenarios are based on informal specifications, so that it is not possible to formally verify properties of such systems. We advocate the need for a general and formal model aiming at ensuring safe executions of interactive multimedia scenarios. Interactive scores (is) is a formalism based on temporal constraints to describe interactive scenarios. We propose new semantics for is based on timed event structures (TES). With such a semantics, we can specify more properties of the system, in particular, properties about execution traces, which are difficult to specify as constraints. We also present an operational semantics of is based on the non-deterministic timed concurrentconstraint calculus and we relate such a semantics to the TES semantics. With the operational semantics, we can describe the behaviour of scores whose timed object durations can be arbitrary integer intervals.
constraint-based concurrency is a simple and elegant formalism of concurrency with monotonic mobile channels, whose history started in early 1980's as a subfield of logic programming. Although it has hardly been r...
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constraint-based concurrency is a simple and elegant formalism of concurrency with monotonic mobile channels, whose history started in early 1980's as a subfield of logic programming. Although it has hardly been recognized as process calculi, there is a close connection between them. In this paper we try to convey the essence of constraint-based concurrency to the process calculi community. We also describe how it smoothly evolved into LMNtal (pronounced "elemental"), a language model based on hierarchical graph rewriting.
Desktop ToonTalk was first released twenty years ago and was successfully used by children as young as 3 to construct computer programs. Uniquely these programs are constructed by demonstration using game elements suc...
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ISBN:
(纸本)9781450343138
Desktop ToonTalk was first released twenty years ago and was successfully used by children as young as 3 to construct computer programs. Uniquely these programs are constructed by demonstration using game elements such as robots, birds, trucks, boxes, and magic wands. The user's avatar inhabits a town where computations can be created and executed in an animated manner. ToonTalk Reborn is a re-conceptualization of ToonTalk for the web. It runs in any modern browser without any plugins. The move to become a web-based tool for web programming has resulted in much being gained and lost.
Search strategies are crucial to efficiently solve constraint satisfaction problems. However, programming search strategies in the existing constraint solvers is a daunting task and constraint-based languages usually ...
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ISBN:
(纸本)9781450372497
Search strategies are crucial to efficiently solve constraint satisfaction problems. However, programming search strategies in the existing constraint solvers is a daunting task and constraint-based languages usually have compositionality issues. We propose space-time programming, a paradigm extending the synchronous language Esterel and timed concurrent constraint programming with backtracking, for creating and composing search strategies. In this formalism, the search strategies are composed in the same way as we compose concurrent processes. Our contributions include the design and behavioral semantics of spacetime programming, and the proofs that spacetime programs are deterministic, reactive and extensive functions. Moreover, spacetime programming provides a bridge between the theoretical foundations of constraint-based concurrency and the practical aspects of constraint solving. We developed a prototype of the compiler that produces search strategies with a small overhead compared to the hard-coded ones.
Session-based concurrency is a type-based approach to the analysis of communication-intensive systems. Correct behavior in these systems may be specified in an operational or declarative style: the former defines how ...
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ISBN:
(纸本)9781450335164
Session-based concurrency is a type-based approach to the analysis of communication-intensive systems. Correct behavior in these systems may be specified in an operational or declarative style: the former defines how interactions are structured;the latter defines governing conditions. In this paper, we investigate the relationship between operational and declarative models of session-based concurrency. We propose two interpretations of session pi-calculus processes as declarative processes in linear concurrent constraint programming (1cc). They offer a basis on which both operational and declarative requirements can be specified and reasoned about. By coupling our interpretations with a type system for 1cc, we obtain robust declarative encodings of pi-calculus mobility.
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