Location-inventory Decision Models For Emergency Processed Grain Supply Network

It is imperative for Chinese local government to optimize processed grain reserves (PGRs) and emergency supply network in the current situation, which is becoming more and more complex and unconventional emergency occurs frequently. When emergencies occur, we can quickly response with a certain amount of refined grain if local governments have established PGRs. Otherwise, we will be very passive when facing emergency, because only in time, power, processing facilities and other resources is abundant, can we obtain refined grain and food to fight against hunger. Emergency Processed Grain Supply Network (EPGSN), which is controlled by local governments and should be multiple constraint conditions, is a three-tiered system consisting of one or more suppliers, storage facilities and supply outlets. In EPGSN, there is a great influence between the numbers of Emergency distribution centre for processed grain, layout and coverage, which is also associated with operating costs and service level of local government. Therefore, how to locate Emergency distribution centre for processed grain for local government has important theoretical significance and practical value.The paper is organized as following. On the basis of the definition of involved concepts, the analysis of structure-function, the Construction of emergency scenario and the present situation of the emergency processed grain supply networks, a logic framework for location-inventory optimization is proposed from the timeliness, economy and reliability based on the statistical analysis of EM-DAT, and the practices of domestic public emergency food emergency supplies. Then it built location-inventory models for emergency processed supply networks with the economic, time and risk constraints respectively considering the three dimensions above. The models built for the emergency processed grain supply networks can be solved with Lagrangian relaxation algorithm and can be verified by using Matlab numerical simulation. Furthermore, it explored the location-inventory model with soft constraints and decision support. At last, the paper verified the models and algorithms with a case study of Changzhou city, which is a typical representative of China’s grain emergency system.We can draw the following conclusions through systematic analysis and models optimization for EPGSN. First, Emergency scenario is the forerunner of designing and constructing EPGSN, which can help and guide local governments to understand "what emergency should deal with" to develop more targeted strategy. Secondly, when designing EPGSN local governments should not only integrate strategic layout and operation process of emergency processed grain facilities, but also weight timeliness, economy and reliability, and a variety of hard and soft constraints in order to make more effective decisions. Thirdly, local governments can make use of social resources and their market channels for reserves, but should design effective and dynamic rotation mode to reduce the total cost of EPGSN because of the more perishable than raw grain. Furthermore, local governments should also weigh the candidate storage facilities in reliability and response time. At last, we present a simple four-step method to design EPGSN with multiple constraints, including timeliness, economy and reliability and other soft constraints.The innovation of this paper is as follows. First, by integrating strategic location, operational inventory into one system and highlighting timeliness, economy and reliability, the paper put forward a TER framework for designing EPGSN. Secondly, by considering the soft constraints, hard constraints and decision behavior characteristics of multiple constraints, the paper proposed a simple four-step method of EPGSN. Finally, based on field research, expert interviews, statistics and typical case analysis, the paper summarizes12emergency scenario of emergency processed grain supply which may occur in china.