TY - JOUR ID - 69686 TI - A fuzzy two-stage capacitated continuous p-centmedian vehicle routing problem: A self-adaptive evolutionary JO - International Journal of Transportation Engineering JA - IJTE LA - en SN - 2322-259X AU - Aghamohamadi, Soroush AU - Tavakkoli-Moghaddam, Reza AU - Rahimi, Yaser AU - Memari, Pedram AD - M.Sc. Student, School of Industrial Engineering, College of Engineering, University of Tehran, Tehran, Iran AD - Professor, School of Industrial Engineering, College of Engineering, University of Tehran, Tehran, Iran AD - Ph.D. candidate, School of Industrial Engineering, College of Engineering, University of Tehran, Tehran, Iran Y1 - 2019 PY - 2019 VL - 7 IS - 2 SP - 217 EP - 232 KW - p-Median and p-Center problem KW - Capacitated vehicle routing KW - Taguchi method KW - Fuzzy set KW - Differential evolution DO - 10.22119/ijte.2018.105564.1376 N2 - In this paper, a two-stage continuous p-center and p-median (namely p-centmedian) problem is developed. In the first step, a location problem is studied to compare the differences between the p-center and p-median by considering facility disruption. P-center problems are common in emergency situations with aim of minimizing the maximum distance between the facilities and costumers, while p-median problem aim is to minimize the total spent distance. Moreover, an integer linear programming is developed to deal with a time-window multi-depot capacitated vehicle routing problem in order to optimize the flows between facilities. This paper compares the mentioned p-center and p-median effects along with the vehicle routing problem as a two-step integrate problem. Since both steps are NP-hard, to deal with the problem in both stages a possibilistic programming, fuzzy single-objective programming is developed and solved by an efficient algorithm, namely self-adaptive differential evolution algorithm. Considering demand as a fuzzy parameter is an important factor and makes the problem more realistic, this feature is more considerable in emergency situations such as p-center problems. To improve the performance of results, the Taguchi method is used. In order to validate the results of the mentioned algorithms of small-sized test problems are compared with GAMS, also other valid meta-heuristics are developed to be compared with the proposed algorithm in large-sized problems. The results show the capability of algorithm to generate near-optimal solutions. Also, the results demonstrate the p-median problem is more volatile against variation in the parameters while the p-center problem is more expensive. UR - http://www.ijte.ir/article_69686.html L1 - http://www.ijte.ir/article_69686_6be6cb6e3487b1c6711e6677cd5c74a0.pdf ER -