The joint location-transportation model based on grey bi-level programming for early post-earthquake relief

<p style='text-indent:20px;'>The initial period after the earthquake is prime time for disaster relief. During this period, it of great value to rationally locate transfer facilities relief materials and effectively arrange transportation materials. Considering characteristics two-level emergency logistics system including uncertain demand, time, multiple varieties materials, shortage supply, multi-transportation modes different urgencies material integrated issue with concern facility location studied. Then, problem formulated as a grey mixed integer bi-level nonlinear programming in which upper-level aims at shortest lower-level maximum fairness distribution. According model, hybrid genetic algorithm designed solve proposed model. Finally, numerical simulation carried out on background 5.12 Wenchuan Earthquake. In addition, validation model verified.</p>