The quadratic assignment problem is a well studied and notoriously difficult combinatorial problem. Recently, a discrete linear formulation of the quadratic assignment problem was presented that solved five previously unsolved instances from the quadratic assignment library, QAPLIB, to optimality. That formulation worked especially well on sparse instances. In this paper we show how to tighten ...

In this paper, we present a simple algorithm to obtain mechanically SDP relaxations for any quadratic or linear program with bivalent variables, starting from an existing linear relaxation of the considered combinatorial problem. A significant advantage of our approach is that we obtain an improvement on the linear relaxation we start from. Moreover, we can take into account all the existing th...

This correspondence presents a linear assignment algorithm for solving the clustering problem. By use of the most dissimilar data as cluster representatives, a linear assignment algorithm is developed based on a linear assignment model for clustering multivariate data. The computational results evaluated using multiple performance criteria show that the clustering algorithm is very effective an...

Students learn more effectively with personally meaningful tasks. Thus, students learn more if they have a say in deciding what specific topics and examples are being discussed in class. Naturally, the instructor knows what topics are important to cover in a course and which ones might be optional. Finding the right balance between students’ preferences and the instructor’s requirements is not ...

This paper presents, formalises and classifies working time accounts (WTAs), a means of achieving flexible production capacity through the flexible organisation of working time. We propose linear programming models to plan working time, using WTA, at companies in the service industry. A computational experiment shows that the models can be solved for any planning problems of reasonable size.