整體的供應鏈環境下,存貨管理對企業而言是相當重要的,若在存貨的規劃與管理上有不適當的處理,將使公司蒙受重大損失。存貨持有多寡可能造成資金的積壓,導致存貨過時、損壞、庫存成本增高、或是造成缺貨而使生產中斷、也會降低顧客服務水準,對公司名譽有影響。因此有效規劃存貨的管理,這對於企業整體在其營運與發展上是相當重要的一環。 本研究即觀察實際情況下,存貨受到不同誤差因素的影響與實際存貨量有所差異,也就是存貨記錄不正確的問題,通常因為不正確的存貨記錄而有了不當的存貨決策,使總成本提高。造成不正確的原因相當多,本研究即建立兩個模式來探討系統存貨記錄與實際庫存量有差異之情形,分別為模式一:人為輸入與領料記錄有誤、偷竊、無法銷售的商品;模式二為盤點錯誤,這些因素對於存貨記錄不正確是重要的關鍵所在。 本研究以單一產品之二階層存貨系統為考量,採定期盤點存貨策略(R, S),以二階層總成本最小化為目標。探討二階層存貨系統若在不同誤差原因下,對於配銷中心或是零售商,甚至是整體績效的影響。利用搜尋法找出最佳存貨水準,並以公式與模擬的方式做驗證,觀察兩個模式在不同決策下與改變不同相關參數值後的各種變化。從中發現不同誤差原因反映出實際情況,當誤差存在時,對上、下游皆會有一定的影響力,為了提高存貨記錄正確性,如何改善及預防誤差發生是相當重要的。
Inventory management plays an important role for enterprises to manage the supply chain well. Up to now, many researchers have devoted themselves to maintain accuracy in inventory count in the field of inventory management. In practice, different inaccuracy factors usually cause the problem of incorrect inventory record. It makes the expected inventory can not satisfy the practical contdition, so that enterprises usually spend more the total inventory cost. To conquer this problem, this research proposes two models to study the influences of different inaccuracy factors on the incorrect inventory record problem. The decision strategies are discussed with Two-echelon periodic-review (R, S) inventory system, when searching for the best inventory policy based on the minimum total cost of the two-echelon inventory system. Further more, their corresponding optimal inventory level is solved by an algorithm. The objective is to evaluate the effect of system related costs and to evaluate the influence of inventory record inaccuracy of the system. An intensive numerical study is conducted and the performance of the two models is compared and analyzed. Through our experiments, we find out that the inventory record inaccury factors indeed damage the performances of each point in a supply chain. Therefore, it is important for enterprises to avaid the inventory record incaccury factors in practice.