A collaborative ant colony metaheuristic for distributed multi-level uncapacitated lot-sizing

The paper presents an ant colony optimization metaheuristic for collaborative planning. Collaborative planning is used to coordinate individual plans of self-interested decision-makers with private information in order to increase the overall benefit of the coalition. The method consists of a new search graph based on encoded solutions. Distributed and private information are integrated via voting mechanisms and via a simple but effective collaborative local search procedure. The approach is applied to a distributed variant of the multi-level lot-sizing problem and evaluated by means of 352 benchmark instances from the literature. The proposed approach clearly outperforms existing approaches on the sets of medium- and large-sized instances. While the best method in the literature so far achieves an average deviation from the best-known non-distributed solutions of 75% for the set of the largest instances, for example, the presented approach reduces the average deviation to 7%.