We consider the hub location problem, where p hubs are chosen from a given set of nodes, each nonhub node is connected to exactly one hub and each hub is connected to a central hub. Links are installed on the arcs of the resulting network to route the traffic. The aim is to find the hub locations and the connections to minimize the link installation cost. We propose two formulations and a heuri...

centralizing and using proper transportation facilities cut down costs and traffic. hub facilities concentrate on flows to cause economic advantage of scale and multimodal transportation helps use the advantage of another transporter. a distinctive feature of this paper is proposing a new mathematical formulation for a three-stage p-hub location routing problem with simultaneous pick-ups and de...

We study the design of capacitated survivable networks using directed p-cycles. A p-cycle is a cycle with at least three arcs, used for rerouting disrupted flow during edge failures. Survivability of the network is accomplished by reserving sufficient slack on directed p-cycles so that if an edge fails, its flow can be rerouted along the p-cycles. We describe a model for designing capacitated s...

Transportation costs are a significant part of capital and operating costs of large open pit mines. Cost efficiency and high reliability of in pit crushing and conveying systems compared to conventional truck-shovel system makes it more appealing to be utilized in modern mining activities. In this paper the suitable location of an in pit crusher is investigated as a single hub location problem....

Hubs are facilities which are used to switch and transfer commodities between terminals (supplies and demands) in many-to-many distribution systems. The p-hub center allocation problem is concerned with allocating demand and supply nodes to hubs in order to route the traffic between origindestination pairs in minimum time. The capacities of the hubs are given. Most of the researches have discus...

Background Telestroke is recognized as a safe and time-efficient way of treating stroke patients. However, admission centers (spokes) are subject to financial charges which can make them reluctant to join the system. We implemented and assessed an economic model supporting our telestroke system, Virtuall, France, which includes one expert center (hub) and six spokes. Methods The model is base...

Abstract Introduction and methods During Coronavirus disease 2019 (COVID-19) pandemic a reduction in ST-elevation acute myocardial infarction with an increase in-hospital mortality has been observed. In our region the temporal trend was sinusoidal peaks valleys. A first outbreak (phase-peak 1 “P-P1”) March 2020 (248.12 cases for 100,000 inhabitants), (phase-valley “P-V1”) May (16.68 inhabitants...

This work introduces a modified MAX MIN Ant System (MMAS) designed to solve the Capacitated pMedians Problem (CPMP). It presents the most relevant steps towards the implementation of an MMAS to solve the CPMP, including some improvements on the original MMAS algorithm, such as the use of a density model in the information heuristics and a local search adapted from the uncapacitated pmedians pro...

Location problems have been the focus of considerable attention both in research and practice for many years. Numerous extensions have been described to broaden its appeal and enhance its applicability. This study proposes a spreadsheet approach for three well-known facility location problems, the p-median problem (PMP), capacitated p-median (CPMP), and maximal covering location problem (MCLP)....