Constraint Propagation and Value Acquisition: Why we should do it Interactively

Evelina Lamma, Paola Mello, Michela Milano, Rita Cucchiara, Marco Gavanelli, Massimo Piccardi

Abstract: In Constraint Satisfaction Problems (CSPs) values belonging to variable domains should be completely known before the constraint propagation process starts. In many applications, however, the acquisition of domain values is a computational expensive process or some domain values could not be available at the beginning of the computation. For this purpose, we introduce an Interactive Constraint Satisfaction Problem (ICSP) model as extension of the widely used CSP model. The variable domain values can be acquired when needed during the resolution process by means of Interactive Constraints, which retrieve (possibly consistent) information. Experimental results on randomly generated CSPs and for 3D object recognition show the effectiveness of the proposed approach.