The hub location problem appears in a variety of applications including airline systems, cargo delivery systems, and telecommunication network design. When we analyze an application separately, we observe that each area has its own characteristics. Hub location problems deal with finding the location of hub facilities and with the allocation of demand nodes to these located hub facilities. This...

The existing works considering the flow-based discount factor in the hub and spoke problems, assume that increasing the amount of flow passing through each edge of network continuously decreases the unit flow transportation cost. Although a higher volume of flow allows for using wider links and consequently cheaper transportation, but the unit of flow enjoys more discounts, quite like replacing...

In this paper, a new priority M/M/c queuing hub covering problem is presented, in which products with high priority are selected for service ahead of those with low priority. In addition, a mixed-integer nonlinear mathematical programming model is presented to find a good solution of the given problem. Due to its computational complexity, we propose a multi-objective parallel simulated annealin...

This paper presents a bi-objective capacitated hub arc location problem with single assignment for designing a metro network with an elastic demand. In the literature, it is widely supposed that the network created with the hub nodes is complete. In this paper, this assumption is relaxed. Moreover, in most hub location problems, the demand is assumed to be static and independent of the location...

The paper discusses the definition and solution of a bi-objective routing problem, namely the bi-objective covering tour problem. The bi-objective CTP is a generalization of the covering tour problem, which means that the covering distance and the associated constraints have been replaced by a new objective. We propose a two-phase cooperative strategy that combines a multi-objective evolutionar...