deman
location-allocation
Chang et al. \cite{ChangEtal2007} recognize the need for a comprehensive optimization tool for flood emergency logistics to help structuring the key involving agents, locating the rescue centers, and allocation of relief-items under the capacity constraints. By considering the different key agents, a head rescue center, the group of regional and local centers, and an external contractor, the authors develop a mathematical model to group the disaster rescue areas (to be managed under a regional center) and classify their level of emergency with the aim of minimizing the expected costs of local rescue center setup, demand and supply shortage, transportation, and procurement. In their multi-group (corresponding to various districts within the disaster area), multi-echelon (corresponding to aforementioned key players), and multi-level (corresponding to various emergency level) multi-echelon, they consider several relation types that are established between players with the aim of delivering the relief-items to the demand points. Accordingly, the authors develop a two-stage stochastic program in which local rescue centers are determined at the first stage followed by the computation of relief-items in all echelons as well as the related transportation plan at the second stage. To solve the problem, the authors employ the sample average approximation scheme (SAA). For the computational study, the authors use Taipei City in Taiwan, which often faces the risks of flood each year, and demonstrate the efficacy of the proposed model and solution technique.