In a Distributed Information Retrieval system, a user submits a query to a broker, which determines how to yield a given number of documents from all possible resource servers. In this paper, we propose a multi-objective model for this resource selection task. In this model, four aspects are considered simultaneously in the choice of the resource: document's relevance to the given query, time, monetary cost, and similarity between resources. An optimized solution is achieved by comparing the performances of all possible candidates. Some variations of the basic model are also given, which improve the basic model's efficiency
