in this paper we present the problem of designing a three level hub center network. in our network, the top level consists of a complete network where a direct link is between all central hubs.  the second and third levels consist of star networks that connect the hubs to central hubs and the demand nodes to hubs and thus to central hubs, respectively. we model this problem in an incomplete net...

In this paper an uncapacitated multiple allocation p-hub median problem is discussed. The model minimizes the transportation cost based on inventory service level at hubs through double paths between hubs. Inventory service level is defined as the percent of inventory shortage of vehicles at hubs according to passengers demand and replenishment time of vehicles. A real data from 25 nodes of mun...

Abstract We consider a hub network design model based on the Stackelberg hub location model, where two firms compete with each other to maximize their own profit. The firm as a leader first locates p hubs and decides which OD pairs should be in services on the condition that the other firm as a follower locates q hubs and decides its strategies in a similar way after that. To avoid the possibil...

We introduce a parameterized version of set cover that generalizes several previously studied problems. Given a ground set V and a collection of subsets Si of V , a feasible solution is a partition of V such that each subset of the partition is included in one of the Si. The problem involves maximizing the mean subset size of the partition, where the mean is the generalized mean of parameter p,...

in this paper, a hierarchical p-hub median problem is considered that all the nodes and arcs on the network have limited capacities. proposed model has three-level where the complete network at the top level consists of the central hubs. the second and third levels consist of hub and demand nodes respectively, which are connected through star networks. also, delivery time restriction is taken i...

The purpose of this paper is to determine where to locate fire-station facilities. The decision of where to locate depends upon a set of tangible and intangible criteria that are unique to a given problem. Thus, the traditional models that incorporate only travel times or travel distances are no longer appropriate. This paper presents a multiple criteria modeling approach, via integer goal prog...

The paper describes a comparative study of multiple-objective metaheuristics on the bi-objective set covering problem. Ten representative methods based on genetic algorithms, multiple start local search, hybrid genetic algorithms and simulated annealing are evaluated in the computational experiment. Nine of the methods are well known from the literature. The paper introduces also a new hybrid g...

Hub facilities serve as switching and transshipment points in transportation and communication networks as well as in logistic systems. Hub networks have an influence on flows on the hub-to-hub links and ensure benefit from economies of scale in inter-hub transportation. The key factors for designing a successful hub-and-spoke network are to determine the optimal number of hubs, to properly loc...