Section: New Results

Constraint Programming

Participants : Maurizio Gabbrielli, Liu Tong.

In Focus, we sometimes make use of constraint solvers (e.g., cloud computing, service-oriented computing). Since a few years we have thus began to develop tools based on constraints. This year, besides refining the work on SUNNY (described elsewhere, see also [40]) we have developed a new tool, NightSplitter, a scheduling tool to optimize (sub)group activities [41]. Humans are social animals and usually organize activities in groups. However, they are often willing to split temporarily a bigger group in subgroups to enhance their preferences. NightSplitter is an on-line tool that is able to plan movie and dinner activities for a group of users, possibly splitting them in subgroups to optimally satisfy their preferences. We first have modeled and proved that this problem is NP-complete. We have then used Constraint Programming (CP) or alternatively Simulated Annealing (SA) to solve it. Empirical results show the feasibility of the approach even for big cities where hundreds of users can select among hundreds of movies and thousands of restaurants. (More information on NightSplitter is found in the section on tools.)