下游廠商領導之供應鏈體系的賽局分析

Abstract

供應鏈體系中有愈來愈多的現象顯示，處於下游的零售商逐漸在供應鏈的環節中扮演愈來愈強勢的角色。在本研究中，即考慮在具有此一情況下，應用賽局理論之互動架構發展供應鏈模型，以探討供應鏈成員間之決策行為。本研究以二階層供應鏈模型為基本架構，成員包含上游兩家生產類似產品，相互具有替代性之製造商，而下游為單一零售商。所發展出四個二階層供應鏈模型，第一個模型為上游製造商同時且各自對零售商所採行之決策進行反應；第二個模型為上游兩製造商間採取勾結以回應零售商之所採取之行動；第三個模型為上游兩製造商間具有領導廠商與追隨廠商之互動架構下，回應零售商之所採取之行動。以上三個模型皆是以零售商應先行決策下所形成之供應鏈模型。而第四個模型則是以供應鏈上游成員先行決策之角度出發，下游成員再跟隨反應之情況，作為與前三個模型之對照。藉由調整上游兩製造商間所生產產品之替代性、生產成本、需求大小及彈性，所得到之數值分析結果為: (1)身為供應鏈體系下之領導者，零售商所獲得之利潤高於上游兩製造商。(2)若上游製造商間存在有勾結時，其可從下游零售商手中贏回部份利益，但下游零售商仍握有大部分利益。(3)當上游製造商間存在領導廠商與追隨廠商情形時，上游廠商利潤提升，且領導廠商獲利程度有可能優於下游零售商。(4)當上下游先行角色互換後，其供應鏈上下游間成員利益之分配明顯逆轉。(5)在下游廠商領導情況下，生產者剩餘以上游廠商間勾結之情況為最大，消費者剩餘與福利則以上游廠商處於競爭情況下為最大。

Some evidence appears the downstream retailer plays a dominant role in the supply chain. This study applies a game-theoretic interactive mechanism to analyze the leading effects in a supply chain. The setting of the two-echelon supply chain in our study comprises two members (manufacturers or vendors) in the upstream, which produce their products with some extent of substitutability, and one member (retailer) in downstream. Four interactive models based on game theory are developed: The first model assumes that upstream members are independent and simultaneous to react to the retailer’s decision. The second model represents these two upstream members taking up collusion to respond the downstream action. The third model applies the leader-follower interactive mechanism between the upstream members. The three models above are under the downstream firm-led situation in the supply chain. The fourth model reverses the setting that upstream members act as the leader, which will be contrast with the previous three downstream firm-led models. All these models’ solution processes are applied by backward induction approach of game theory. By applying some numerical examples with different scenarios, there are some findings: (i) As the downstream leader in the supply chain, the retailer gains profit more than the upstream manufacturers. (ii) If the duopolistic manufacturers act in union, they can take back a little of benefits from downstream retailer, however, the downstream member still owns the biggest share of profit. (iii) Applying leader-follower interactive mechanism between upstream members improves their profits, the leader manufacturer may outperform downstream retailer in profit under some condition. (iv) There is drastic change in profit distribution as the leader-follower roles redirection between the downstream and upstream members. (v) Among the downstream firm-led models, consumer surplus and welfare exhibit identical order across cases: Upstream members’ competition facilitates the best welfare, collusion leads to the worst welfare.