The present study introduced a novel hierarchical hub set covering problem with capacity constraints. This study showed the significance of fixed charge costs for locating facilities, assigning hub links and designing a productivity network. The proposed model employs mixed integer programming to locate facilities and establish links between nodes according to the travel time between an origin-...

The p-hub center problem is to locate p hubs and to allocate non-hub nodes to hub nodes such that the maximum travel time (or distance) between any origin–destination pair is minimized. We address the p-hub center allocation problem, a subproblem of the location problem, where hub locations are given. We present complexity results and IP formulations for several versions of the problem. We esta...

hub covering location problem, network design,   single machine scheduling, genetic algorithm,   shuffled frog leaping algorithm   hub location problems (hlp) are synthetic optimization problems that appears in telecommunication and transportation networks where nodes send and receive commodities (i.e., data transmissions, passengers transportation, express packages, postal deliveries, etc.) th...

The hierarchical hub location problem is encountered three-level network that is applied in production-distribution system, education system, emergency medical services, telecommunication network, etc. This paper addresses the hierarchical hub covering problem with single assignment accounting for mandatory dispersion of central hubs restriction as a special case. This formulation with incorpor...

In this study a hierarchical hub location problem with two layers is considered. The first layer includes small hubs and the second one includes a star-shaped network central hub. The considered case is a cargo delivery network where there is hierarchy between hubs. All the hubs and links are capacitated and there are three kinds of commodities for each of which there is a special kind of vehic...

Hub location problems, with the hub-and-spoke network structure, involve locating hub facilities, allocating the non-hubs (spokes) to the hubs, and determining the path for each origin-destination pair. In a pure hub-and-spoke network, all hubs, which act as intermediate switching or transshipment points for internodal flows, are fully interconnected and none of the non-hubs are directly connec...

Stem cells can be controlled by their local microenvironment, known as the stem cell niche. The Drosophila testes contain a morphologically distinct niche called the hub, composed of a cluster of between 8 and 20 cells known as hub cells, which contact and regulate germline stem cells (GSCs) and somatic cyst stem cells (CySCs). Both hub cells and CySCs originate from somatic gonadal precursor c...