Timed soft concurrent constraint programs: An interleaved and a parallel approach. Issue 6 (November 2015)

• Record Type: Journal Article
• Authors: BISTARELLI, STEFANO; GABBRIELLI, MAURIZIO; MEO, MARIA CHIARA; SANTINI, FRANCESCO
• Is Part Of: Theory and practice of logic programming. Volume 15:Issue 6(2015)
• Page Start: 743
• Page End: 782
• Publication Date: 2015-11
• Subjects: Logic programming -- Periodicals; Artificial intelligence -- Computer programs -- Periodicals; Constraint programming (Computer science) -- Periodicals; 005.115
• DOI: 10.1017/S1471068414000106
• Languages: English
• ISSNs: 1471-0684

Abstract

<abstract abstract-type="normal"> <title>Abstract</title> <p>We propose a timed and soft extension of Concurrent Constraint Programming. The time extension is based on the hypothesis of <italic>bounded asynchrony</italic>: The computation takes a bounded period of time and is measured by a discrete global clock. Action prefixing is then considered as the syntactic marker that distinguishes a time instant from the next one. Supported by soft constraints instead of crisp ones, <italic>tell</italic> and <italic>ask</italic> agents are now equipped with a preference (or consistency) threshold, which is used to determine their success or suspension. In this paper, we provide a language to describe the agents' behavior, together with its operational and denotational semantics, for which we also prove the compositionality and correctness properties. After presenting a semantics using maximal parallelism of actions, we also describe a version for their interleaving on a single processor (with maximal parallelism for time elapsing). Coordinating agents that need to take decisions on both preference values and time events may benefit from this language.</p> </abstract>