ing Soft Constraints: Some Experimental Results on Fuzzy CSPs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 Stefano Bistarelli, Francesca Rossi, and Isabella Pilan Tradeoff Generation Using Soft Constraints . . . . . . . . . . . . . . . . . . . . . . . . . . . 124 Stefano Bistarelli, Jerome Kelleher, and Barry O’Sullivan Experimental Evaluation of Interchangeability in Soft CSPs . . . . . . . . . . . . . 140 Nicoleta Neagu, Stefano Bistarelli, and Boi Faltings Language Issues A Rule Language for Interaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154 Carlos Castro, Eric Monfroy, and Christophe Ringeissen A Generic Trace Schema for the Portability of CP(FD) Debugging Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171 Ludovic Langevine, Pierre Deransart, and Mireille Ducass´e