ارايه‌ي مدل چند‌‌هدفه‌ي بهينه‌سازي استوار براي برنامه‌ريزي لجستيكي در واكنش به زلزله با در نظر گرفتن مراكز توزيع و درمان موقت

A Multi-objective Robust Optimization Model for Logistics Planning in an Earthquake Response Phase, considering Temporary Distribution Centers and Medical Centers

پس از وقوع هر بحران يا رويداد طبيعي، نظير زلزله، مهم‌ترين واكنش حمل و نقل افراد آسيب‌ديده و توزيع كالا‌هاست. در اين نوشتار يك مدل چند‌هدفه، چند پريودي براي برنامه‌ريزي لجستيكي كالا و مصدومان پس از زلزله با در نظر گرفتن مراكز درماني موقت و مراكز توزيع موقت ارايه شده است. افزون بر اين، در اين مدل به مكان‌يابي مراكز توزيع موقت و تعيين ظرفيت مراكز درماني موقت و بيمارستان‌ها نيز توجه شده است. با توجه به ماهيت غيرقطعي پارامتر‌هايي همچون ميزان تقاضا، مقدار منابع موجود، تعداد افراد آسيب‌ديده و ظرفيت درماني منطقه از رويكرد بهينه‌سازي استوار براي مدل‌كردن و برخورد با عدم قطعيت استفاده شده است. مدل ارايه شده به دنبال كمينه‌كردن تعداد افراد سرويس داده نشده، ميزان تقاضاي برآورده نشده و نيز تعداد كل وسيله‌ي نقليه‌ي استفاده شده است. براي حل مدل نيز با توجه به متفاوت بودن اهميت اهداف از رويكرد سلسله‌مراتبي استفاده كرده‌ايم. در نهايت با استفاده از مدل ارايه‌شده، برنامه‌ريزي لجستيكي كالا و مصدومان را پس از زلزله‌ي فرضي در منطقه 17 شهر تهران مورد مطالعه قرار داده‌ايم.

Logistics management is a key issue that should be considered for an appropriate response to earthquakes. The problem of interest is the outgrowth of a recent paper [2], where they focused on the logistics of relief items among distribution centers, and the demand nodes and logistics of injured persons among affected areas and hospitals for a prolonged period of time. The main drawback of their approach is that vehicles require to travel long distances among demand points, distribution centers and hospitals. In fact, they did not consider intermediate/temporary nodes to facilitate the logistics operations. In practice, temporary depots and medical centers are also established to facilitate the logistics of commodities and for serving injured people. This paper presents a multi-objective, multi-period model to manage the logistics of both commodities and injured people in the earthquake response phase. In the presented model, the optimal location of temporary distribution centers and the optimal capacity of medical centers are considered. Relief items can either be directly delivered from distribution centers to affected areas or they can be shipped from distribution centers to temporary depots, and, then, from temporary depots to affected areas. According to uncertain parameters, such as demand quantity, supply quantity, number of injured persons and capacity of medical centers, a robust optimization method is applied to deal with uncertainties. The presented model attempts to minimize the number of unserved persons, the number of unsatisfied demands and the number of utilized vehicles. The first two objectives are humanitarian objectives and the third leads to cost effectiveness. The objective functions are of different importance. Humanitarian objectives are naturally more important than the third objective. Therefore, the hierarchical approach proposed in [2] is applied to solve the presented model. This approach achieves the optimal solution if the multi-objective model has a single optimal solution. Otherwise, it attains one of the optimal solutions. Finally, the logistics of commodities and injured persons in region 17 of Tehran are studied using the proposed model.