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This project is conducted by researchers at the University of York and the University of St. Andrews. The project's aim is to develop an automated system that, given a specification of a problem, can generate one or more constraint programs that can solve the problem.
ESSENCE is a language we are developing; it allows a combinatorial (optimisation) problem to be sepcified at a level of abstraction above that at which modelling decisions are made. Version 1.1.0 of the language is now fully defined.
ESSENCE: A Constraint Language for Specifying Combinatorial Problems. By Alan M Frisch, Warwick Harvey, Chris Jefferson, Bernadette Martinez Hernandez and Ian Miguel. To appear in Constraints, 13(3),July 2008. Specification Catalog A catalogue of problems and their specifications in ESSENCE and other languages. This catalogue can also be accessed through a tree that organises the problems into categories. Other Papers on ESSENCE The Design of ESSENCE: A Constraint Language for Specifying Combinatorial Problems. By Alan M Frisch, Matthew Grum, Chris Jefferson, Bernadette Martinez Hernandez and Ian Miguel. Proc. of the 20th International Joint Conference on Artificial Intelligence (IJCAI), January 2007.
The Concept and Provenance of Unnamed, Indistinguishable Types. By Alan M Frisch and Ian Miguel. September, 2006. The Essence of ESSENCE: A Constraint Language for Specifying Combinatorial Problems,. By Alan M Frisch, Matthew Grum, Chris Jefferson, Bernadette Martinez Hernandez and Ian Miguel. In Proc. of the Fourth International Workshop on Modelling and Reformulating Constraint Satisfaction Problems, pages 73-88, October 2005. Technical Documents The syntax of ESSENCE Version 1.1.0.. The syntax of MiniESSENCE, the subset of ESSENCE that is currently implemented. Talks Why ESSENCE? Frequently Asked Questions about a New Language for Specifying Combinatorial Problems. Delivered by Alan M Frisch at the Fifth International Workshop on Constraint Modelling and Reformulation, Nantes, France, September, 2006. CONJURE is a rule-based system that refines an ESSENCE Specification into a concrete constraint program that is similar to programs supported by existing constraint-solving toolkits.
Extensible Automated Constraint Modelling. By Ozgur Akgun, Ian Miguel, Chris Jefferson, Alan M Frisch and Brahim Hnich. In Proc. of the 25th AAAI Conference on Artificial Intelligence 2011. Other Papers on CONJURE The Rules of Constraint Modelling. By Alan M Frisch, Chris Jefferson, Bernadette Martinez Hernandez and Ian Miguel. In Proc. of the 19th International Joint Conference on Artificial Intelligence (IJCAI), 109-116, 2005. (This paper introduces the concept of automated modelling and describes the architecture of a prototype system.) A paper on CONJURE that we published in the 2004 Workshop on Modelling and Reformulating Constraint Satisfaction Problems. This paper is superseded by the one immediately above. The Open Stacks Problem: An Automated Modelling Case Study. By Ozgur Akgun, Ian Miguel and Chris Jefferson. In Proc. of the ERCIM Workshop on Constraint Solving and Constraint Logic Programming (CSCLP), 15-27, 2011. Symmetry in the Generation of Constraint Models. By Alan M. Frisch, Chris Jefferson, Bernadette Martinez Hernandez and Ian Miguel. International Symmetry Conference, 2007. Talks on CONJURE A talk we have given on CONJURE. Symmetry and the Generation of Constraint Models. An invited talk given by Alan M Frisch at the Workshop on Automated Reasoning, August, 2005. Technical Documents
ESSENCE' is a close to a subset of ESSENCE that provides a level of abstraction comparable to that provided by existing constraint toolkits and languages. It is therefore a constraint modelling langauge rather than a problem specification language. ESSENCE' is basically ESSENCE with all the features for abstraction removed . TAILOR translates ESSENCE' models to input code for either of two constraint solvers: Gecode and Minion. In can also generate FlatZinc, which is itself supported by several solvers. TAILOR is notable for the powerful optimisations that it performs in during translation. On this TAILOR website you can download the code, read an introduction to ESSENCE' and examine a catalog of ESSENCE' models. A page of ESSENCE' models has been written by Hakan Kjellerstrand. Papers on ESSENCE' and TAILOR Optimising Quantified Expressions in Constraint Models Ian Gent, Ian Miguel, Andrea Rendl, ModRef 2010 Effective Compilation of Constraint Models Andrea Rendl, PhD Thesis, January 2010 The Cost of Flattening with Common Subexpression Elimination Andrea Rendl, Ian Miguel and Ian P. Gent, in Proceedings of ModRef 2009, pp. 117-131 Common Subexpressions in Constraint Models of Planning Problems Andrea Rendl, Ian Miguel, Ian P. Gent and Peter Gregory, pp128-135, in SARA 2009, AAAI Press. Enhancing Constraint Model Instances during Tailoring Andrea Rendl, Ian Miguel, Ian P. Gent and Chris Jefferson, pp120-127, in SARA 2009, AAAI Press. A Constraint Model for the Settlers Planning Domain Peter Gregory and Andrea Rendl, at PLANSIG 2008, pp41-49, 2008. Constraint Model Enhancement by Common Subexpression Elimination
Andrea Rendl, Ian P. Gent and Ian Miguel.
Proceedings of the
Doctoral Consortium
at
CP 2008
, pp72-78, 2008. Common Subexpression Elimination in Automated Constraint Modelling
Ian P. Gent, Ian Miguel and Andrea Rendl.
Proceedings of the
Workshop on Modeling and Solving Problems with Constraints
, pp24-30, 2008. Reformulation during Automated Constraint Modelling Andrea Rendl, Ian P. Gent, Ian Miguel. Doctoral Programme of CP 2007, pp139-145, 2007. Tailoring Solver-independent Constraint Models: A Case Study with Essence' and Minion Ian P. Gent, Ian Miguel, Andrea Rendl. Proceedings of SARA 2007, pp184-199, 2007. Related Papers The Systematic Gernaration of Channelled Models in Constraints Satisfaction. By Bernadette Martinez Hernandez. PhD Dissertation, University of York, November, 2008. Representations in Constraint Programming. By Chris Jefferson. PhD Dissertation, University of York, June, 2007. Abstract of PhD Dissertation: Representations in Constraint Programming. By Chris Jefferson. June 2009. The Proper Treatment of Undefinedness in Constraint Languages. By Alan M Frisch and Peter J Stuckey. In I. Gent, editor, Proceedings of the 15th International Conference on Principles and Practice of Constraint Programming, volume 5732 of LNCS, page 367-382. Springer-Verlag, 2009. Small Sets of Ordering Constraints for some Families of Variable Symmetries. By Andy Grayland, Chris Jefferson, Ian Miguel and Colva Roney-Dougal. International Symmetry Conference, 2007. The Automatic Generation of Redundant Representations and Channelling Constraints. By Bernadette Martinez Hernandez and Alan M Frisch. In Proc. of the Fifth International Workshop on Constraint Modelling and Reformulation,, September, 2006. Representations of Sets and Multisets in Constraint Programming, By Christopher Jefferson and Alan. M. Frisch. Proc. of the Fourth International Workshop on Modelling and Reformulating Constraint Satisfaction Problems, pages 102-116, October 2005. The Systematic Generation of Channelling Constraints. By Bernadette Martinez-Hernandez and Alan M. Frisch. Proc. of the Fourth International Workshop on Modelling and Reformulating Constraint Satisfaction Problems, pages 89-101, October 2005. Transforming and Refining Abstract Constraint Specifications. By Alan M Frisch, Brahim Hnich, Ian Miguel, Barbara M. Smith and Toby Walsh. Proceedings of the 6th International Symposium on Abstraction, Reformulation and Approximation (SARA), LNAI 3607, 76-91, 2005. Generating Effective Constraint Programs: An Application of Automated Reasoning. By Alan M. Frisch, Chris Jefferson, Benadette Martinez-Hernandez and Ian Miguel. Proceedings of the 11th Workshop on Automated Reasoning, 2004. Symmetry-breaking as a Prelude to Implied Constraints: A Constraint Modelling Pattern By Alan M Frisch, Chris Jefferson and Ian Miguel. Proceedings of the 16th European Conference on Artifical Intelligence, pages 171-175, 2004. Department of Computer Science, University of York School of Computer Science, University of St. Andrews This web-page is maintained by Alan Frisch, and was last changed on 14 June 2011. |