The covering of a graph with (possibly disjoint) connected subgraphs is fundamental problem in theory. In this paper, we study version to cover graph's vertices by subject lower and upper weight bounds, propose column generation approach dynamically generate feasible promising subgraphs. Our focus on the solution pricing which turns out be variant NP-hard Maximum Weight Connected Subgraph Probl...

In the fast developing field of expression quantitative traits loci (eQTL) studies, great interests have been concentrated on detecting genomic regions containing transcriptional regulators that influence multiple expression phenotypes (trans-hubs). In this paper, we develop statistical methods for e-QTL mapping and propose a new procedure for investigating candidate trans-hubs. We use data fro...

We address the problem of designing two-level networks protected against single edge failures. A set of nodes must be partitioned into terminals and hubs, hubs must be connected through a backbone network, and terminals must be assigned to hubs and connected to them through access networks, being the objective to minimize the total cost. We consider two survivable structures, two-edge connected...

We consider the node-capacitated routing problem in an undirected ring network along with its fractional relaxation, the node-capacitated multicommodity flow problem. For the feasibility problem, Farkas’ lemma provides a characterization for general undirected graphs asserting roughly that there exists such a flow if and only if the so-called distance inequality holds for every choice of distan...

In this talk we present a unified Variable Neighborhood Search (VNS) algorithm for the Capacitated Arc Routing Problem (CARP) and some of its variants the Capacitated Arc Routing Problem with Intermediate Facilities (CARPIF) and the Capacitated Arc Routing Problem with Intermediate Facilities and Length restrictions (CLARPIF). Routing problems represent one of the most prominent classes of mode...

We study network traffic dynamics in a two-dimensional communication network with regular nodes and hubs. If the network experiences heavy message traffic, congestion occurs due to the finite capacity of the nodes. We discuss strategies to manipulate hub capacity and hub connections to relieve congestion and define a coefficient of betweenness centrality (CBC), a direct measure of network traff...

In a two-capacitated spanning tree of a complete graph with a distinguished root vertex v, every component of the induced subgraph on V\{v} has at most two vertices. We give a complete, non-redundant characterization of the polytope defined by the convex hull of the incidence vectors of two-capacitated spanning trees. This polytope is the intersection of the spanning tree polytope on the given ...

Many graph problems seek subsets of their vertices that maximize or minimize objective functions on the vertices. Among these are the capacitated p-median problem, the geometric connected dominating set problem, the capacitated k-center problem, and the traveling tourist problem. Prior genetic algorithms research in this area applied a simple mutation of an allele by random replacement. Recentl...

In previous Extension articles, we discussed traditional Ethernet and its dependency on repeater sets to expand the length of these networks. As Ethernet evolved to incorporate twisted-pair cabling and star topology, a repeating hub was necessary in order to connect the various link segments together. With the introduction of switching hubs as a replacement for repeating hubs, network performan...