著者:所属(別形式) | Josai University, Department of Business Administration / Aichi-Gakuin University, Department of Management / Aichi-Gakuin University, Department of Management / Josai University, Department of Business Administration / Josai University, Department of Business Administration |
抄録 | サプライチェーン内において生産企業と販売店の間で,製品の流れと情報の流れを整合するために,共有すべき情報,すなわち,需要量が揺らぎ変動をするとき,効率的な生産販売活動を遂行するために,生産企業は需要量の変動を把握する販売店とどのような情報を共有すべきかという問題を扱う.生産企業が,Push型の生産販売方式にしたがって,一定の需要量の見込み値を生産指示量に設定し生産販売を続けると,如何に妥当な需要量の見込み値を採用しても,需要量が揺らぎ変動をすれば,生産の過剰や不足が生じ,長期間の間に,在庫量あるいは欠品量が無限に増大する.在庫量や欠品量が増大することを回避するには,生産指示量を,各単位期間に生じる需要量の見込み値にその期間までに生じた在庫量や欠品量の分だけ加減して,設定する必要がある.その結果,最も効率的な生産方式は,第1単位期間の生産指示量を単位期間あたりの需要量の平均値に設定し,第2単位期間以後の各単位期間の生産指示量を直前の単位期間に生じた需要量に等しく設定する,すなわち,単位期間あたりの生産指示量を需要量に一単位期間遅れで追随させる需要遅延追随生産になる.販売活動に同期した生産活動を展開するには,生産企業と販売店が,直前単位期間に生じた需要量の実数の情報を共有する必要がある.数理解析により上記の結論を導き,在庫量や欠品量の時系列変化の具体的な事例をシミュレーションにより示す.生産指示量を設定する際に,在庫量と対等に受注残(=欠品量)にも配慮することが重要である.本生産調整法は,受注残を在庫量と対等に扱うことにより,在庫量だけでなく受注残をも少なくできる. This paper addresses information sharing for the purpose of adjusting the product flow with the information flow between a manufacturing company and a sales company in a supply chain. In other words, if demand fluctuates, the issue is what data should be shared by a manufacturing company with a sales company to realize efficient production-sales activities. Supposing a group company continues to produce and sell a product under a pull-type system, and sets the production rate in a unit period at a value fixed according to the estimates of demand. This will inevitably cause overproduction or insufficient production because demand fluctuates, following a probability distribution. Without any production adjustments, when demand fluctuates, either the product will be out-of-stock or the company will be forced to pile up excessive inventory of the product due to overproduction. The inventory or the backlog may increase infinitely over a long period of time. In this paper, a method for making production adjustments to minimize the inventory, as well as the backlog, is derived from the following empirical prescription: the production rate in a unit period should be the estimated demand for the period corrected by the inventory and the backlog piled up in the previous unit periods. This empirical prescription provides the following simple method of applying production adjustments: the production rate in a unit period should be exactly the same as the demand quantity in the previous unit period. This production adjustment method, obtained by mathematical analyses, is shown here. This paper also presents some examples of time-series changes of inventory and backlog data through simulations. One finding is that by treating both inventory and backlog equally, this proposed adjustment method not only decreases the inventory, but also decreases the backlog. |