This paper presents HAS-QAP, a hybrid ant colony system coupled with a local search, applied to the quadratic assignment problem. HAS-QAP uses pheromone trail information to perform modifications on QAP solutions, unlike more traditional ant systems that use pheromone trail information to construct complete solutions. HAS-QAP is analysed and compared with some of the best heuristics available f...

THE quadratic assignement problem (QAP) can be described as an optimizing the assignment a set of facilities to a set of locations with given costs between the locations and given flows between the facilities in order to minimize the sum of the product between flows and distances. A concrete example, would be a hospital planning optimization the location of various medical facilities in order t...

The quadratic assignment problem (QAP) is one of the most studied NPhard problems with various practical applications. In this work, we propose a powerful population-based memetic algorithm (called BMA) for QAP. BMA integrates an effective local optimization algorithm called Breakout Local Search (BLS) within the evolutionary computing framework which itself is based on a uniform crossover, a f...

The paper proposes, compares and analyses different memory-based meta-heuristics for the quadratic assignment problem (QAP). Two of these methods (FANT and GDH) are new while two others (HAS-QAP and GTSH) are among the best for structured QAP instances. These methods are based on ant systems and genetic algorithms and they are presented under a unified general scheme, called adaptive memory pro...

We consider the problem of assigning the test variants of a written exam to the desks of a classroom in such a way that desks that are close-by receive different variants. The problem is a generalization of the Vertex Coloring and we model it as a binary quadratic problem. Exact solution methods based on reformulating the problem in a convex way and applying a general-purpose solver are discuss...

Quadratic Assignment is a basic problem in combinatorial optimization, which generalizes several other problems such as Traveling Salesman, Linear Arrangement, Dense k Subgraph, and Clustering with given sizes. The input to the Quadratic Assignment Problem consists of two n × n symmetric non-negative matrices W = (wi,j) and D = (di,j). Given matrices W , D, and a permutation π : [n] → [n], the ...