The modularity maximization model proposed by Newman and Girvan for the identification of communities in networks works for general graphs possibly with loop...

A new hierarchical divisive algorithm is proposed for identifying communities in complex networks. To that effect, the definition of <i>community in the weak...

Using the AutoGraphiX system, we obtain conjectures of the form <img src="/cgi-bin/mimetex.cgi?l(n) \leq q_1 \oplus i(G)\leq u(n)"> where <img src="/cgi-bin...

Let <i>G</i> be a connected graph of order <i>n</i>. The algebraic connectivity of <i>G</i> is the second smallest eigenvalue of the Laplacian matrix of <i>G...

A crew pairing is a sequence of flights, connections and rests that start and end at a crew base and is assigned to a single crew. The crew pairing problem c...

This paper considers the application of a Variable Neighborhood Search (VNS) algorithm for finite-horizon (<i>H</i> stages) Markov Decision Processes (MDPs),...

The Traveling Salesman Problem and the Vehicle Routing Problem are two of the most popular problems in the field of combinatorial optimization. The purpose ...

As of April 2007, the European Union has new regulations concerning driver working hours. These rules force the placement of breaks and rests into the vehicl...

The <i>proximity</i> <img src="/cgi-bin/mimetex.cgi?\pi = \pi (G)"> of a connected graph <i>G</i> is the minimum, over all vertices, of the average distance ...

This paper presents a general framework for formulating cutting planes in the context of column generation for integer programs. Valid inequalities can be de...

We address the problem of locating in the plane objects such as segments, arcs of circumferences, arbitrary convex sets, their complements or their boundarie...

Harmonic means clustering is a variant of Minimum sum of squares clustering (which is sometimes called <i>K</i>-means clustering), designed to alleviate the ...

Variable neighborhood search (VNS) is a metaheuristic for solving combinatorial and global optimization problems whose basic idea is a systematic change o...

Let <i>Q = D + A</i> denote the signless Laplacian matrix of a graph <i>G</i> of order <i>n</i>, where <i>D</i> is the diagonal matrix of the degrees and <i...

The <i>Vehicle routing Problem</i> (VRP) was introduced 50 years ago by Dantzig and Ramser under the title "The Truck Dispatching Problem". The study of the ...

Given a set of scheduled flights that must be operated by the same aircraft type, the aircraft routing problem (ARP) consists of building anonymous aircraft ...

This paper presents an efficient approach for realistic modelling of internal transport systems. The weakness of the former methods in tracking the traffic w...

Khalifeh, Yousefi-Azari, Ashrafi and Wagner [European J. Combin. 30 (2009) 1149-1163] conjectured that for a connected graph <i>G</i> on <i>n</i> vertices...

The proximity <img src="/cgi-bin/mimetex.cgi?\pi"> of a graph <i>G</i> is the minimum average distance from a vertex of <i>G</i> to all others. Similarly, th...

In the <i>Vehicle Routing Problem with Deliveries, Selective Pickups and Time Windows</i>, the set of customers is the union of <i>delivery customers</i> and...