We examine the feasibility polyhedron of the uncapacitated hub location problem (UHL) with multiple allocation, which has applications in the elds of air passenger and cargo transportation, telecommunication and postal delivery services. In particular we determine the dimension and derive some classes of facets for this polyhedron. We develop a general rule about lifting facets from the uncapac...

Recently the concept of facility efficiency, which defined by data envelopment analysis (DEA), introduced as a location modeling objective, that provides facilities location’s effect on their performance in serving demands. By combining the DEA models with the location problem, two types of “efficiencies” are optimized: spatial efficiency which measured by finding the least cost location and al...

A good hub centre will effectively help expand agglomeration economy effects and increase competitive advantages for global shipping carrier-based logistics service providers (GSLPs). Hence, the selection of hub location of logistics centre is very important for the GSLP companies. In light of this, the main purpose of this paper is to develop an integrated fuzzy MCDM model to evaluate the best...

The present paper deals with a variant of hub location problems (HLP): the uncapacitated single allocation p-Hub median problem (USApHMP). This consists to jointly locate facilities and allocate demand nodes these selected facilities. objective function is minimize routing demands between any origin destination pair nodes. known be NP-hard. Based on artificial immune systems (AIS) framework, th...

The numerical simulation of unsteady flow in multi-stage turbomachinery is computationally expensive. A parallel code using message-passing interface libraries, which was developed to reduce the turnaround time and the cost of computation, is presented in this paper. The paper describes the details of the parallel algorithm, including the parallelization rationale, domain decomposition and proc...

Design of network, through which data, packages or even people can be transported, is an important issue for achieving a desired level of service quality at an acceptable cost. For this purpose, it is possible to design a network comprised of nodes that are connected to each other with dedicated lines. However, this kind of solution will not be cost effective. In order to decrease the total tra...

Hubs are special centers that used for switching, transferring and handling freight or passengers in transportation systems. The hub location problem deals with locating hub facilities and allocating demand nodes to hubs in order to route the traffic between origin–destination pairs. Aiming at minimizing the total costs, maximizing utilization of transporters, maximizing the service level, etc....

In contrast to the classical location-allocation models, the location-routing problem (LRP) integrates vehicle routing and scheduling aspects in the location planning process. A survey and classification scheme of location-routing is e.g. proposed by [3] and [2]. This paper presents a LRP of a company which distributes finished cars. This LRP is decomposed into two steps. In the first step a se...