A Multi-level Hybrid Framework for the Deterministic Job-shop Scheduling Problem

Techniques that combine myopic problem specific methods and a meta-strategy, which guides the search out of local optimum, are currently providing the best results. Such hybrid methods are known as iterated local search algorithms or meta-heuristics. Despite the good results achieved by these methods the inability of many current meta-heuristics to provide a wide exploration of the search space in order to overcome strong local minima is highlighted here. Consequently in this work the evolutionary techniques of scatter search (SS) and its generalised form, path relinking (PR) are applied as they can provide the appropriate mixture of intensification (concentrate the search in promising areas) and diversification (search unvisited regions) and they can be integrated at various levels with intelligent search methods such as tabu