緊急救災物資配送中心區位選擇模式

A Model for Locating Urgent Relief Distribution Centers

本研究提出穩健節點p中心模式，從一個候選設施點集合中選取p個設施點作為緊急救災物資配送中心，並指派災區的物資發放站給配送中心。本研究採用穩健最佳化方法，將救災物資配送中心到災區間之運送時間的不確定性以區間資料表示，求解目標為極小化在最差狀況情境下到達所有災區物資發放站的最遠距離。由於以連續區間資料來表示運送時間的不確定性可能會導致無限多種可能的運送時間情境，使得決定最差狀況情境變得非常困難，為解決此一難處，本研究提出一個定理能夠有效率地決定最差狀況，情境。由於此問題為NP-hard，本研究根據此定理，發展以模擬退火法為基礎的啟發式解法，並以隨機產生的例題測試演算法求解績效。最後，本研究將所發展的模式應用於921集集大地震的實例中。

This paper presents a robust vertex p-center model for locating Urgent Relief Distribution Centers (URDCs) on a set of given candidate sites, as well as assigning relief stations in affected areas to those URDCs. Particularly addressed in the model are uncertain travel times that are represented using intervals (or ranges), instead of probability distributions. The objective is to locate p URDCs so as to minimize the maximum travel time between URDCs and affected areas under the worst-case scenario. A key problem property that can facilitate the determination of the worst-case scenario, among an infinite number of possible scenarios, is analyzed. Since the problem is NP-hard, a simulated annealing (SA)-based heuristic is developed, to find robust solutions. Numerical results show that the proposed heuristic is effective and efficient in obtaining robust solutions. Finally, the model and its algorithm are applied to a real case with the data .from the 921 Chi-Chi Earthquake disaster.