This paper focuses on a generic model for service network design, which includes asset positioning and utilization through constraints on asset availability at terminals. We denote these relations as “design-balance constraints” and focus on the design-balanced capacitated multi-commodity network design model, a generalization of the capacitated multi-commodity network design model generally us...

Metric inequalities, cutset inequalities and Benders feasibility cuts are three families of valid inequalities that have been widely used in different algorithms for network design problems. This article sheds some light on the interrelations between these three families of inequalities. In particular, we show that cutset inequalities are a subset of the Benders feasibility cuts, and that Bende...

The problem of finding a Capacitated Minimum Spanning Tree asks for connecting a set of client nodes to a root node through a minimum cost tree network, subject to capacity constraints on all links. This paper reports on our design, implementation and performance evaluation of a hybrid Ant Colony Optimization algorithm for finding Capacitated Minimum Spanning Trees. Our Ant Colony Optimization ...

This paper investigates the minimum cost multicommodity flow problem with uncertain costs and uncertain capacities. Uncertainty theory is used to deal with indeterminacy factors in uncertain network. An (α, β)-minimum cost multicommodity flow model is formulated. Some properties of the model are analyzed. An equivalence relationship between the (α, β)-minimum cost multicommodity flow and the mi...

In this work we address a capacitated hub problem arising from a Telecommunications application. In this problem we must choose the routes and the hubs to use in order to send a set of commodities from sources to destinations in a given capacitated network with a minimum cost. The capacities and costs of the arcs and hubs are given, and the graph connecting the hubs is not assumed to be complet...

In this dissertation we study two problems from the area of network design. The first part discusses the multicommodity buy-at-bulk network design problem, a problem that occurs naturally in the design of telecommunication and transportation networks. We are given an underlying graph and associated with each edge of the graph, a cost function that represents the price of routing demand along th...

We propose an exact solution method for a routing and capacity installation problem in networks. Given an input graph, the problem is to route traffic from a set of source nodes to a sink node and to install transmission facilities on the edges of the graph to accommodate the flow at minimum cost. We give a branch and bound algorithm that solves relaxations obtained by approximating the non-con...

The fixed-charge Capacitated Multi-commodity Network Design (CMND) is a well-known problem of both practical and theoretical significance. Network design models represent a wide variety of planning and operation management issues in transportation telecommunication, logistics, production and distribution. In this paper, Ant Colony Optimization (ACO) based neighborhoods are proposed for CMND pro...

In this paper, we present an exact solution procedure for the design of two-layer wavelength division multiplexing (WDM) optical networks with wavelength changers and bifurcated flows. This design problem closely resembles the traditional multicommodity flow problem, except that in the case of WDM optical networks, we are concerned with the routing of multiple commodities in two network layers....

We consider a fundamental problem, called QoS-aware Multicommodity Flow, for assessing robustness in transportation planning. It constitutes a natural generalization of the weighted multicommodity ow problem, where the demands and commodity values are elastic to the Quality-of-Service (QoS) characteristics of the underlying network. The problem is also fundamental in other domains beyond transp...