The irregular strip packing problem asks to place a set of polygons within a rectangular strip of fixed height without overlap, so as to minimize the strip width required. We consider an overlap minimization problem which minimizes the amount of overlap penalty for all pairs of polygons within a given bound of strip width. We propose a local search algorithm which translates a polygon in horizo...

Iterated local search (ILS) is a general and powerful metaheuristic which provides an easily implementable way of improving the performance of local search algorithms. In this article we consider the application of ILS to the permutation flow shop problem (FSP), a strongly studied problem in machine scheduling. We experimentally investigate the effect of specific implementation choices in our I...

The multiple depot vehicle scheduling problem (MDVSP) is a well-known and important problem arising in public transport. Although many solution approaches have been published in the literature, algorithms using metaheuristics appeared only very recently (Large Neighborhood Search and Tabu Search). In this paper, we introduce an Iterated Local Search algorithm for the MDVSP, incorporating a neig...

Given a set of n elements separated by a pairwise distance matrix, the minimum differential dispersion problem (Min-Diff DP) aims to identify a subset ofm elements (m < n) such that the difference between the maximum sum and the minimum sum of the inter-element distances between any two chosen elements is minimized. We propose an effective iterated local search (denoted by ILS MinDiff) for Min-...

Iterated local search is a stochastic local search (SLS) method that combines a perturbation step with an embedded local search algorithm. In this article, we propose a new way of hybridizing iterated local search. It consists in using an iterated local search as the embedded local search algorithm inside another iterated local search. This nesting of local searches and iterated local searches ...

In this paper, we show how an extended Guided Local Search (GLS) can be applied to the Quadratic Assignment Problem (QAP). GLS is a general, penalty-based meta-heuristic, which sits on top of local search algorithms, to help guide them out of local minima. We present empirical results of applying several extended versions of GLS to the QAP, and show that these extensions can improve the range o...

This paper presents an Iterated Tabu Search algorithm (denoted by ITSPUCC) for solving the problem of Packing Unequal Circles in a Circle. The algorithm exploits the continuous and combinatorial nature of the unequal circles packing problem. It uses a continuous local optimization method to generate locally optimal packings. Meanwhile, it builds a neighborhood structure on the set of local mini...

Local search is a traditional technique to solve combinatorial search problems which has raised much interest in recent years. The design and implementation of local search algorithms is not an easy task in general and may require considerable experimentation and programming eeort. However, contrary to global search, little support is available to assist the design and implementation of local s...

This paper addresses a variation of the Traveling Salesman Problem with Pickup and Delivery in which loading and unloading operations have to be executed in a first-in-first-out fashion. It provides an integer programming formulation of the problem. It also describes five operators for improving a feasible solution, and two heuristics that utilize these operators: a probabilistic tabu search al...