Variable Neighborhood Search (VNS) is a recent and effective metaheuristic for solving combinatorial and global optimization problems. It is capable of esca...

The global <i>k</i>-means heuristic is a recently proposed (Likas et al. 2003) incremental approach for minimum sum-of-squares clustering of a set <i>X</i> ...

In this paper we develop a Variable neighborhood search (VNS) heuristic for solving Mixed-Integer Programs (MIP’s). It uses CPLEX, the general-purpose MIP s...

An upper bound is given on the variance of degrees of graphs with <i>n</i> vertices, <i>m</i> edges and maximum degree &Delta;. Particular cases of chemical...

The algebraic connectivity <i>a(G)</i> of a graph <i>G = (V,E)</i> is the second smallest eigenvalue of its Laplacian matrix. Using the AutoGraphiX (AGX) sys...

The uniting feature of combinatorial optimization and extremal graph theory is that in both areas one should &#64257;nd extrema of a function defined in most...

Conjectures in graph theory have multiple forms and involve graph invariants, graph classes, subgraphs, minors and other concepts in premisses and/or conclu...

Computer-assisted and automated conjecture-making in graph theory is reviewed, focusing on the three operational systems GRAPH, Graffiti and AutoGraphiX (AGX...

The problem retained for the ROADEF'2001 international challenge was a frequency assignment problem with polarization constraints (FAPP). This NP-hard probl...

Two ways for bounding <i>n</i>-variables functions over a box, based on interval evalu- ations of first order derivatives, are compared. The optimal Baumann...

The shortest path problem with resource constraints consists of finding the minimum cost path between two specified points while respecting constraints on r...

We consider the bilevel uncapacitated facility location problem with user preferences. It is known that this model may be reformulated as a one-level locati...

The multiprocessor scheduling problem with communication delays that we consider in this paper consists of finding a static schedule of an arbitrary task gra...

In this exploratory study, a segmentation analysis of a shopping mall’s customers is conducted according to the activities they performed during their visit,...

We consider the design of a hybrid opto-electronic network with grooming. We propose a model in which we take into account the fact that grooming traffic req...

A zone-dependent fixed cost is introduced within the framework of minisum location of facilities in the continuous space. An efficient algorithm for determin...

This paper examines the convergence properties of two well-known heuristics: variable neighborhood search (VNS) and random multistart local search (MLS). Bot...

When applying the 2-opt heuristic to the travelling salesman problem, selecting the best improvement at each iteration gives worse results on average than se...

The berth allocation problem is to allocate space along the quayside to incoming ship at a container terminal in order to minimize some objective function....

This paper reviews state-of-the-art models and approaches for solving a wide variety of public transit problems encountered at the strategic, tactical, and...