A LOCAL SEARCH APPROACH TO SOLVE INCOMPLETE FUZZY CSPs

Mirco Gelain, Maria Silvia Pini, Francesca Rossi, Kristen Brent Venable, Toby Walsh

2011

Abstract

We consider fuzzy constraint problems where some of the preferences may be unspecified. This models, for example, settings where agents are distributed and have privacy issues, or where there is an ongoing preference elicitation process. In this context, we study how to find an optimal solution without having to wait for all the preferences. In particular, we define local search algorithms that interleave search and preference elicitation, with the goal to find a solution which is ”necessarily optimal”, that is, optimal no matter what the missing data are, while asking the user to reveal as few preferences as possible. While in the past this problem has been tackled with a branch & bound approach, which was guaranteed to find a solution with this property, we now want to see whether a local search approach can solve such problems optimally, or obtain a good quality solution, with fewer resources. At each step, our local search algorithm moves from the current solution to a new one, which differs in the value of a variable. The variable to reassign and its new value are chosen so to maximize the quality of the next solution. To compute this, we elicit some of the missing preferences in the neighbor solutions. Experimental results on randomly generated fuzzy CSPs with missing preferences show that our local search approach is promising, both in terms of percentage of elicited preferences and scaling properties.

References

  1. Aglanda, A., Codognet, P., and Zimmer, L. (2004). An adaptive search for the NSCSPs. In Proc. CSCLP'04.
  2. Bistarelli, S., Montanari, U., and Rossi, F. (1997). Semiring-based constraint solving and optimization. Journal of the ACM, 44(2):201-236.
  3. Codognet, P. and Diaz, D. (2001). Yet another local search method for constraint solving. In Proc. SAGA'01.
  4. Fargier, H., Lang, J., and Schiex, T. (1996). Mixed constraint satisfaction: a framework for decision problems under incomplete knowledge. In Proceedings of AAAI'96, volume 1, pages 175-180. AAAI Press.
  5. Gelain, M., Pini, M. S., Rossi, F., and Venable, K. B. (2007). Dealing with incomplete preferences in soft constraint problems. In Proc. CP'07, LNCS 4741, pages 286- 300. Springer.
  6. Gelain, M., Pini, M. S., Rossi, F., Venable, K. B., and Walsh, T. (2008). Dealing with incomplete preferences in soft constraint problems. In Proc. CP'08, LNCS 5202, pages 402-417. Springer.
  7. Gelain, M., Pini, M. S., Rossi, F., Venable, K. B., and Walsh, T. (2010a). Elicitation strategies for soft constraint problems with missing preferences: Properties, algorithms and experimental studies. AI Journal, 174(3-4):270-294.
  8. Gelain, M., Pini, M. S., Rossi, F., Venable, K. B., and Walsh., T. (2010b). A local search approach to solve incomplete fuzzy and weighted csps. In Proc. CP'10 Workshop on Preferences and Soft Constraints.
  9. Glover, F. and Laguna, M. (1997). Tabu Search. Kluwer, Norwell, MA.
  10. Hoos, H. H. and Stutzle, T. (2004). Stochastic Local Search: Foundations and Applications. Elsevier - Morgan Kaufmann.
  11. Pini, M. S., Rossi, F., and Venable, K. B. (2010). Soft constraint problems with uncontrollable variables. Journal of Experimental & Theoretical Artificial Intelligence.
  12. Rossi, F., Beek, P. V., and Walsh, T. (2006). Handbook of Constraint Programming. Elsevier.
Download


Paper Citation


in Harvard Style

Gelain M., Pini M., Rossi F., Brent Venable K. and Walsh T. (2011). A LOCAL SEARCH APPROACH TO SOLVE INCOMPLETE FUZZY CSPs . In Proceedings of the 3rd International Conference on Agents and Artificial Intelligence - Volume 1: ICAART, ISBN 978-989-8425-40-9, pages 582-585. DOI: 10.5220/0003174505820585


in Bibtex Style

@conference{icaart11,
author={Mirco Gelain and Maria Silvia Pini and Francesca Rossi and Kristen Brent Venable and Toby Walsh},
title={A LOCAL SEARCH APPROACH TO SOLVE INCOMPLETE FUZZY CSPs},
booktitle={Proceedings of the 3rd International Conference on Agents and Artificial Intelligence - Volume 1: ICAART,},
year={2011},
pages={582-585},
publisher={SciTePress},
organization={INSTICC},
doi={10.5220/0003174505820585},
isbn={978-989-8425-40-9},
}


in EndNote Style

TY - CONF
JO - Proceedings of the 3rd International Conference on Agents and Artificial Intelligence - Volume 1: ICAART,
TI - A LOCAL SEARCH APPROACH TO SOLVE INCOMPLETE FUZZY CSPs
SN - 978-989-8425-40-9
AU - Gelain M.
AU - Pini M.
AU - Rossi F.
AU - Brent Venable K.
AU - Walsh T.
PY - 2011
SP - 582
EP - 585
DO - 10.5220/0003174505820585