This paper uses the energy hub concept to meet the water, heat and electricity demand of a power plant in the Qeshm island in south of Iran. Given the power plant’s high potential for waste heat recovery and some scenarios were considered using the hub energy concept based on energy, exergy, environmental and economic analyzes in terms of meeting the demands of the hub and purchasing/selling en...

In cutting and packing problems, Dual Feasible Functions (DFFs) represent a well established tool for deriving high quality lower bounds in very short times. A well-known DFF lower bounding approach consists of using DFFs to rapidly generate feasible values for the dual variables of a Column Generation (CG) program (i.e., of an extended formulation commonly associated to CG). This paper present...

The optimal locating of facilities has large effects on economic benefits, providing satisfactory service and levels of customer satisfaction. One of the new topics discussed in location problems is hub location and hub facilities are subject to unpredictable disruptions. This paper proposes a nonlinear integer model for reliable single allocation hub location problem that considers backup hub,...

Facility-location problems have several applications in telecommunications, industrial transportation and distribution, etc. One of the most well-known facility-location problems is the p-median problem. This work addresses an application of the capacitated p-median problem to a real-world problem. We propose a genetic algorithm (GA) to solve the capacitated pmedian problem. The proposed GA use...

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...

We study algorithmic and structural aspects of connectivity in hypergraphs. Given a hypergraph H = (V, E) with n= |V |, m= |E| and p = ∑ e∈E |e| the fastest known algorithm to compute a global minimum cut in H runs in O(np) time for the uncapacitated case, and in O(np+ n2 log n) time for the capacitated case. We show the following new results. • Given an uncapacitated hypergraph H and an intege...

0377-2217/$ see front matter 2011 Elsevier B.V. A doi:10.1016/j.ejor.2011.01.014 ⇑ Tel.: +90 312 290 27 68; fax: +90 312 266 40 54. E-mail address: [email protected] In this paper, we study allocation strategies and their effects on total routing costs in hub networks. Given a set of nodes with pairwise traffic demands, the p-hub median problem is the problem of choosing p nodes as hub loca...

Having recently established a faecal microbiota transplantation (FMT) programme, we raise two points about Spector and Knight’s editorial on FMT. Firstly, despite the UK’s relatively permissive regulatory framework on FMT, we encountered considerable obstacles to establishing an NHS programme. Donor screening is expensive (>£500 (€703; $755)/screen/donor, repeated regularly). It is unclear whet...

In this paper, a complete review of published researches about hierarchical facility location and hub network problems is presented. Hierarchical network is a system where facilities with different service levels interact in a top-down way or vice versa. In Hierarchical systems, service levels are composed of different facilities. Published papers from (1970) to (2015) have been studied and a c...