Optimal search-relocation trade-off in Markovian-target searching

Abstract

In this study, a standard moving-target search model was extended with a multiple-search-speed option, whereby a trade-off is enabled between the increased detection chances owing to the searcher''''''''s better location and the increased uncertainty of the target''''''''s location resulting from the diminished search performance incurred in the relocation. This enhances the detection probability of the output search path and, thereby, the model''''''''s practicality. However, the scalability of the solution method is essential to its implementation, as the basic model is already NP-hard. We developed an efficient heuristic by combining the idea of approximate nondetection probability minimization and a hybridized shortest-path heuristic that exploits the fast-mixing property of the Markov chain. According to the results of an intensive experiment, the heuristic achieves a near-optimal trade-off within a very reasonable computation time. (C) 2008 Elsevier Ltd. All rights reserved.