近年來,市場已走向全球化,因此為了滿足產品多樣性的需求,企業藉由精實生產模式,達到生產成本降低並且提高產品品質。然而,受到供應鏈全球化的影響,使供應商分佈在世界各地,當供應商分佈範圍越廣時,不可預期的風險也會隨著增加,例如天災、勞工糾紛以及恐怖攻擊...等等。一旦發生不可預期的狀況時,將對供應鏈造成嚴重的衝擊,進而使公司損失慘重。因此可以藉由風險管理的方法來評估供應商斷貨對公司所造成的影響。 本研究應用精實生產系統於等候線網路,探討當供應商斷貨時,在現有的基本庫存下,供應鏈持續運作的時間。在本研究中持續運作的時間(直到沒有原物料而停產的時間)即稱之為維持性(survivability)。 首先,本研究建構一個單一系統的模式,可透過模式計算系統的維持性;並且,進一步延伸探討多站系統之模式,其中因數學模式過於複雜,故採用階段性機率分佈(phase-type distribution)來估計其系統維持性;最後,藉由數據分析模式的合理性。本研究的目的在於分析當供應商停止供貨後,供應鏈系統基於現有的半成品與零組件庫存,還能使系統正常營運多久,提供管理者作為參考。
Globalization leads to a competitive market demanding various products at low costs and good quality as well as quick and on-time delivery. Lean production is one of the solutions. Because of globalization, the supplier may be dispersed all over the world. As the supplier's dispersion increase, the risk of unexpected situations will increase, too. Such as natural disasters, labor strikes, or terrorist attacks. Once it happened, it may cause serious disruption risk. One way to assess the consequent risk when suffering the disruption is to know how long it can continue to operate based on the existing resources when the disruption occurs or how long the production in a supply chain will survive. In this study, we model a lean production system as a queueing network, and assess how long the system can survive based on existing resources. Firstly, we consider a system with single station, it is easier to assess the survivability of the system. After the previous work, we extend the system into multiple stations and use phase-type approximation to estimate survivability of the system. The objective of this study is to analyze how long the system can continue to operate based on the existing parts and semi-products when one of the suppliers suffering disruption. This study can provide references to managers.