21 research outputs found

    An integrated user-system approach for shelter location and evacuation routing

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    Disasters are catastrophic events that can severely affect the life conditions of entire communities. Disaster-related issues are usually dealt with according to the Disaster Operations Management framework, which is composed of four phases: mitigation, preparedness, response, and recovery. This work focuses on two crucial operations belonging to the response phase: shelter location and evacuation of endangered populations. Specifically, the ultimate scope of this paper is to present some applications of a scenario-based mixed-integer two-stage linear program which integrates shelter location with two different types of evacuation, self- (or car-based) evacuation and supported- (or bus-based) evacuation, namely the Scenario-Indexed Shelter Location and Evacuation Routing (SISLER) model. The SISLER model is solved using an off-the-shelf optimization software, whose performance is improved through the addition of some valid inequalities which are added at the root node of the solution tree to improve the lower bound. Computational results are reported for both testbed instances and a realistic case study (Sioux Falls network). The analysis of the solutions provides some useful managerial insights for relevant stakeholders working within the shelter location and evacuation planning area, such as emergency management practitioners and public service providers

    A Multi-Exchange Heuristic for the Single Source Capacitated Facility Location Problem

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    We present a very large-scale neighborhood (VLSN) search algorithm for the capacitated facility location problem with single-source constraints. The neighborhood structures are induced by customer multiexchanges and by facility moves. We consider both traditional single-customer multi-exchanges, detected on a suitably defined customer improvement graph, and more innovative multicustomer multi-exchanges, detected on a facility improvement graph dynamically built through the use of a greedy scheme. Computational results for some benchmark instances are reported that demonstrate the effectiveness of the approach for solving large-scale problems. A further test on real data involving an Italian factory is also presented

    Integrated capture process for purification of plasmid DNA based on aqueous two phase separation

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    Facility systems may be vulnerable to a disaster, whether caused by intention, an accident, or by an act of nature. When disrupting events do occur, services may be degraded or even destroyed. This chapter addresses problems of disruption associated with facility based service systems. Three main questions often arise when dealing with a possible disaster: 1) how bad can it get? 2) is there a way in which we can protect our system from such an outcome? and 3) is there a way in which we can incorporate such issues in our future designs and plans? This chapter addresses each of these main questions with respect to several classic location problems. Specifically, it discusses recent location models under disaster events along three main streams of research: facility interdiction, facility protection, and resilient design
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