TY - JOUR UR - http://dx.doi.org/10.1007/s10009-002-0104-3 KW - Directed Model Checking KW - Trail-directed Model Checking KW - Heuristic Search KW - Partial Order Reduction KW - HSF-SPIN TI - Directed explicit-state model checking in the validation of communication protocols AV - none N2 - The success of model checking is largely based on its ability to efficiently locate errors in software designs. If an error is found, a model checker produces a trail that shows how the error state can be reached, which greatly facilitates debugging. However, while current model checkers find error states efficiently, the counterexamples are often unnecessarily lengthy, which hampers error explanation. This is due to the use of naive search algorithms in the state space exploration. In this paper we present approaches to the use of heuristic search algorithms in explicit-state model checking. We present the class of A * directed search algorithms and propose heuristics together with bitstate compression techniques for the search of safety property violations. We achieve great reductions in the length of the error trails, and in some instances render problems analyzable by exploring a much smaller number of states than standard depth-first search. We then suggest an improvement of the nested depth-first search algorithm and show how it can be used together with A * to improve the search for liveness property violations. Our approach to directed explicit-state model checking has been implemented in a tool set called HSF-SPIN. We provide experimental results from the protocol validation domain using HSF-SPIN. SN - 1433-2779 EP - 267 ID - eprints167 N1 - The original publication is available at www.springerlink.com IS - 2-3 JF - International Journal on Software Tools for Technology Transfer (STTT) Y1 - 2004/// SP - 247 PB - Springer A1 - Edelkamp, Stefan A1 - Leue, Stefan A1 - Lluch-Lafuente, Alberto VL - 5 ER -