Given a graph <i>G</i> and a bipartition of its vertices, the edge-ratio is the minimum for both classes so defined of their number of internal edges divid...

The GRIEG model is a hybrid model of demo-economic projections that combines two approaches: the econometric approach - based on the micro-economy - of the N...

Community detection in networks based on modularity maximization is currently done with hierarchical divisive or agglomerative as well as with partitioning h...

Heuristics are widely applied to modularity maximization models for the identification of communities in complex networks. We present an approach to be appli...

Le but de cet article est de décrire et de résoudre un nouveau et important problème auquel font face les compagnies maritimes spécialisées dans le transport...

We present a new column generation algorithm for the determination of a classifier in the two classes LAD (Logical Analysis of Data) model. Unlike existing a...

We study extremal graphs for the extremal values of the second largest <i>Q</i>-eigenvalue of a connected graph. We first characterize all simple connected g...

Normalized cut is one of the most popular graph clustering criteria. The main approaches proposed for its resolution are spectral clustering methods (e.g. [1...

Traditionally, IP Network planning and design is mostly based on average delay or loss constraints which can often be easily calculated. Jitter, on the othe...

We present a new general variable neighborhood search approach for the uncapacitated single allocation <i>p</i>-hub median problem in networks. This NP-hard ...

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...

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 ...

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...

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...