ACCLAIM aims to:
- extend the foundations of concurrent constraint programming to account for a richer class of conputational phenomena
- develop efficient constraint techniques to tackle new application areas and to produce extensible general-purpose constraint systems
- develop frameworks and techniques for compile-time analysis and optimisation of concurrent constraint programs
- improve the implementation technology of concurrent constraint languages to be competitive with imperative languages, and to achieve a high degree of parallel execution on multi-processor architectures.
Research on concurrent constraint programming, will help to provide a framework for designing and implementing advanced computational tools for the development of complex, symbolic computational tasks in areas such as knowledge representation and reasoning, design, diagnosis, simulation, scheduling, and natural language understanding.
So far 17 public deliverable reports have been produced, which are available on request from the coordinator. Most correspond to articles published in international journals and conferences.
Novel language designs have been investigated that better support the needs of applications based on constraints: ALK, Oz, LIFE, clp(FD), and CLP(PB). For these, sequential and parallel prototype implementations are being developed.
Several problem oriented constraint systems have been defined: finite domain constraints (FD), feature tree constraints (FT), order sorted feature constraints (OSF), piece wise linear constraints, list constraints, interval constraints, and pseudo-Boolean constraints (PB). For these, efficient constraint, solving algorithms are being designed, analysed, and implemented. Compile time program analysis frameworks based on abstract interpretation have been proposed. These will benefit both parallel and sequential implementations by providing safe approximations of the runtime behaviour of programs.
The formal properties of programs have been analysed. For this purpose an algebraic semantics for a concurrent abstract machine (CHARM) has been developed, and a true concurrency semantics for both indeterministic and nondeterministic programs has been provided.
APPROACH AND METHODS
ACCLAIM brings together an interdisciplinary team of the leading European researchers in this area. In addition, fruitful cooperation with leading US researchers is expected.
The consortium expects to generate the technological base that will allow the development and deployment of path-breaking, semantically based, performance-efficient parallel systems for symbolic
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