考慮責任運區、車隊運能與路線規劃合併補貨問題之研究

Abstract

在供應鏈的管理中，存貨的控制扮演極為重要的角色；而企業中現有最盛行的存貨 控制，仍以批量生產、批量補貨的方式為其主流。批量生產及補貨時間的協調攸關於批 量模式生產與存貨控制系統中的兩種主要成本項目：存貨持有成本及設置成本。在分裝 (packaging)及配送(distribution)系統中，經理人有機會經由多種產品的合併補貨 (joint replenishment)，節省主要的設置成本(major setup costs)；例如：換模換線成本或採購作 業成本(ordering cost)。是故，如何協調產品之補貨排程（及補貨批量），成為供應鏈管 理中存貨控制必須審慎研究的一項重要課題。在文獻中將此類問題，即稱為「合併補貨 問題」(Joint Replenishment Problem, JRP)。 而在實際生產/配銷系統中，經理人在規劃補貨作業時，尚須考量配合其運輸作業。 而運輸作業中最重要的三項規劃項目為：運輸車輛的運區規劃、車輛運能的規劃與車輛 運輸路線規劃。故本研究在探討合併補貨問題時，除了存貨持有成本及設置成本外，尚 須考量補貨作業同時所產生的運輸成本，並加入車輛運能的限制。而且決策情境中，就 長期而言，經理人必須規劃運輸車隊之車輛運能，而且須因應產品需求率之變化，調整 規劃每一車輛負責配送的區域（或稱為「運區」）；就短期而言，經理人必須決定補貨週 期，各產品補貨的時間，運補派遣的車輛及各車輛行駛的路線，滿足車輛運能的限制， 並求達到最低的平均總成本。 本研究為一件三年期的研究計畫，將朝針對下列三個研究議題，分三年進行探討： 第一研究議題：考量運區規劃下合併補貨問題之研究 第二研究議題：結合車輛運能規劃之合併補貨與批量排程問題之研究 第三研究議題：考量車輛運區與路線規劃下合併補貨與批量排程問題之研究 吾人將針對各研究議題，分別推導建構數學模式，進行數學模式的理論分析，設法 運用理論分析之結果，提出設計具有效率的求解演算法。再運用數據實驗，驗證本研究 計畫所提出之演算法，可以同時確保運算效率及求解品質，可以作為實際生產/配銷系統 中面對合併補貨問題的決策者，訂定最佳的運區規劃、運能規劃、補貨週期及補貨排程 策略。

Inventory control and management plays a key role in supply chain management. Batch replenishment is one of the most popular inventory control policies among most of the production and distribution systems in supply chains. The coordination of lot sizing and scheduling for batch replenishment determines the two major cost items: inventory holding cost and setup cost. For some packaging and distribution systems, the decision makers are able to take advantage of jointly replenish several products so as to save the major setup cost, which could be the change-over cost or the ordering cost. Therefore, it becomes a critical research topic to determine the lot size of products and to coordinate the replenishment schedule in supply chain management, and it is well known as the Joint Replenishment Problem in the literature. The managers have to include the transportation operations as working on the replenishment plan for production and distribution systems in the real world. The three most important planning activities are the delivery-zone planning of transportation vehicles, the capacity planning of transportation vehicles, and the routing planning of transportation vehicles. In this research project, we will consider not only the inventory holding cost and the setup cost, but also the transportation costs incurred in the replenishment operations, and also take into account the constraints of vehicle capacity. In the long run, the managers should take care of the capacity planning of transportation vehicles, and also, are responsible to the delivery-zone planning to meet the demand change of products. In the short run, the managers have to determine the replenishment cycles and the assigned vehicle for each product, and the route of each vehicle to meet the capacity constraint of each vehicle and to minimize the total average costs in the system. This is a three-year project proposal that would investigate the following three subjects. The first research topic: On the joint replenishment problem considering the delivery-zone planning of the transportation fleet. The second research topic: On the joint replenishment and lot scheduling problem considering the vehicle capacity planning. The third research topic: On the joint replenishment and lot scheduling problem considering the vehicle routing and delivery-zone planning. For each research topic, we plan to do the following task items. First, we shall derive the corresponding mathematical model. Then, we conduct full theoretical analysis that provides interesting insights into the optimality structure of the mathematical model. Also, by making use of our theoretical results, we propose appropriate methodology and/or derive effective algorithms that are able to obtain a close-to-optimal solution or an optimal solution for the corresponding scenario. Finally, we will verify that the proposed solution methodology via extensive numerical experiments. We are confident that the outputs of this project shall serve as effective decision-support tools that assist the managers face the joint replenishment and lot scheduling problem with the considerations of delivery-zone planning, vehicle capacity constraints and vehicle routing planning.