Network hub locations problems: the state of the art

Cataloged from PDF version of article.Hubs are special facilities that serve as switching, transshipment and sorting points in many-to-many distribution systems. The hub location problem is concerned with locating hub facilities and allocating demand nodes to hubs in order to route the traffic between origin-destination pairs. In this paper we classify and survey network hub location models. We also include some recent trends on hub location and provide a synthesis of the literature. (C) 2007 Elsevier B.V. All rights reserved

Evaluating the Vulnerability of Time-Sensitive Transportation Networks: A Hub Center Interdiction Problem

This work is licensed under a Creative Commons Attribution 4.0 International License.Time-sensitive transportation systems have received increasing research attention recently. Examples of time-sensitive networks include those of perishable goods, high-value commodity, and express delivery. Much research has been devoted to optimally locating key facilities such as transportation hubs to minimize transit time. However, there is a lack of research attention to the reliability and vulnerability of time-sensitive transportation networks. Such issues cannot be ignored as facilities can be lost due to reasons such as extreme weather, equipment malfunction, and even intentional attacks. This paper proposes a hub interdiction center (HIC) model for evaluating the vulnerability of time-sensitive hub-and-spoke networks under disruptions. The model identifies the set of hub facilities whose loss will lead to the greatest increase in the worst-case transit time. From a planning perspective, such hubs are critical facilities that should be protected or enhanced by preventive measures. An efficient integer linear programming (ILP) formulation of the new model is developed. Computational experiments on a widely used US air passenger dataset show that losing a small number of hub facilities can double the maximum transit time

Optimisation of connections to a fibre network

Stronger competition together with the development of new technologies have forced the Telecom Service Providers (TSP's) in the Netherlands to look for sophisticated optimisation methods to reduce the costs of their communication services especially for new areas such as the application of fibre technology.Fibre is being considered as the transmission medium of the future because fibre deadens the signals much less than the traditional media such as copper and coax, a lot of data can be transmitted at the same time and there are only a few failures. Another advantage is that fibre cables are thin and light so that they can be put into the ground rather easily.This article describes optimisation models with the objective to minimise the costs of constructing and managing a fibre network.The optimisation models have been developed to support decisions about the design and use of a fibre network and are based on the practical situation at Enertel being one of the new TSP’s. For Enertel a national backbone was already realised. The main problem to be solved concerned the optimisation of the access to the fibre network.

On hub location problems in geographically flexible networks

The authors were partially supported by research groups SEJ-584 and FQM-331 (Junta de Andalucia) and projects MTM2016-74983-C02-01 (Spanish Ministry of Education and Science/FEDER), FEDER-US-1256951, P18-FR-1422, P18-FR-2369 (Junta de Andalucia), CEI-3FQM331 (Andalucia Tech), and NetmeetData (Fundacion BBVA - Big Data 2019). We also would like to acknowledge Elena Fernandez (Universidad de Cadiz) for her useful and detailed comments on previous versions of this manuscript.In this paper, we propose an extension of the uncapacitated hub location problem where the potential positions of the hubs are not fixed in advance. Instead, they are allowed to belong to a region around an initial discrete set of nodes. We give a general framework in which the collection, transportation, and distribution costs are based on norm-based distances and the hub-activation setup costs depend not only on the location of the hub that are opened but also on the size of the region where they are placed. Two alternative mathematical programming formulations are proposed. The first one is a compact formulation while the second one involves a family of constraints of exponential size that we separate efficiently giving rise to a branch-and-cut algorithm. The results of an extensive computational experience are reported showing the advantages of each of the approaches.Junta de Andalucia SEJ-584 FQM-331 FEDER-US-1256951 P18-FR-1422 P18-FR-2369Spanish Government European Commission MTM2016-74983-C02-01Andalucia Tech CEI-3FQM331NetmeetData (Fundacion BBVA - Big Data 2019

Effects of population size for location-aware node placement in WMNs: evaluation by a genetic algorithm--based approach

Wireless mesh networks (WMNs) are cost-efficient networks that have the potential to serve as an infrastructure for advanced location-based services. Location service is a desired feature for WMNs to support location-oriented applications. WMNs are also interesting infrastructures for supporting ubiquitous multimedia Internet access for mobile or fixed mesh clients. In order to efficiently support such services and offering QoS, the optimized placement of mesh router nodes is very important. Indeed, such optimized mesh placement can support location service managed in the mesh and keep the rate of location updates low...Peer ReviewedPostprint (author's final draft