Local search: A guide for the information retrieval practitioner

There are a number of combinatorial optimisation problems in information retrieval in which the use of local search methods are worthwhile. The purpose of this paper is to show how local search can be used to solve some well known tasks in information retrieval (IR), how previous research in the field is piecemeal, bereft of a structure and methodologically flawed, and to suggest more rigorous ways of applying local search methods to solve IR problems. We provide a query based taxonomy for analysing the use of local search in IR tasks and an overview of issues such as fitness functions, statistical significance and test collections when conducting experiments on combinatorial optimisation problems. The paper gives a guide on the pitfalls and problems for IR practitioners who wish to use local search to solve their research issues, and gives practical advice on the use of such methods. The query based taxonomy is a novel structure which can be used by the IR practitioner in order to examine the use of local search in IR

General Terms

In this paper we introduce an application of real-coded genetic algorithms to the problem of consistent graph layout and exploring the role of mutation for this particular problem. We introduce several forms of mutation, some of which being specific to this problem, and show that the choice of this operator can have a great impact on the performance of the algorithm

FACET DETECTION AND VISUALIZING LOCAL STRUCTURE IN GRAPHS

In this paper we present an algorithm for facet detection in graphs. We define the facets as simple cycles in the graph minimizing the length. Our algorithm detects the local structure of simple cycles intersecting in a particular vertex of the graph. For this purpose, we reduce the problem to an instance of the Traveling Salesman in an induced co-cyclic graph and use a method inspired from the minimum spanning tree to construct a circuit solution. Our algorithm found a correct solution for most of the cases we tested it on