Centre for Operational Research and Logistics

Events and Seminars

Research Seminar

Reliable Hub Network Design

Hub network design involves the location of hub sites in a network through which flows from origins to destinations must be routed at least cost. Many practical applications of hub location exist for transportation, telecommunications, and other logistics systems. This presentation will focus on a critical issue in hub location planning that has, thus far, received little attention in the literature: hub reliability. The few existing studies dealing with hub reliability unrealistically assume that either dedicated backups can be located which never fail or that at most one unreliable hub will fail at any given time. A more general approach for designing reliable hub networks would be to account for multiple, random hub failures. To this end, formulation and solution techniques are proposed for the uncapacitated, single allocation p-hub median location problem with independent hub failure probabilities. A mixed integer nonlinear programming model is formulated for locating unreliable hubs and assigning demand nodes to hubs in order to minimize the expected demand weighted cost of customer flows plus a penalty in the event all hubs fail.

One of the key accomplishments is the development of a linear model which embeds a specialized flow network structure referred to as a probability lattice. A probability lattice extends the concept of probability chains recently introduced in the OR literature for evaluating high-order probability terms. A probability lattice involves interlinking multiple probability chains together to form a backbone probability chain and series of spur probability chains. A Tabu search algorithm which makes use of a parallel computing strategy is also proposed to find optimal to near optimal solutions for large problem instances. Experimental results carried out on several benchmark instances show the efficiency of the linearized model and heuristic algorithm. Compared to a standard hub median model that disregards the potential for hub failures, the proposed model produces solutions that serve larger numbers of customers and at lower cost per customer.

Speaker

Dr Jesse O’Hanley, Kent Business School, University of Kent, UK


Venue

Lion Gate Building, LG 2.01


Date and Time

Thu, 16 Oct 2014, 13:00 - 14:00 (BST)


For further information or any enquiries please contact our event co-ordinator, Jana Ries, at corl@port.ac.uk

Biography: Dr Jesse O’Hanley is a senior lecturer in the Kent Business School, University of Kent, UK. He obtained his Ph.D. in Environmental Science, Policy & Management from the University of California, Berkeley. He joined the Kent Business School in 2006. Prior to this, he was a postdoctoral research fellow in the Environmental Change Institute at the University of Oxford and before that a management consultant to the high-tech industry in Silicon Valley. His research focuses on applications of statistics, optimization and other operations research techniques to natural resource management, healthcare delivery, and supply chain management. He is currently involved in a number of ongoing research projects, including prioritizing the repair/removal of river barriers that block the migration of salmon and other migratory fish (in collaboration with US Fish and Wildlife Service), the optimal scheduling of blood donation session (in collaboration with NHS Blood and Transplant), and the development of advanced modeling and solution techniques for designing robust and reliable facility networks.

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