Tedarik Belirsizliği Altında Eşzamanlı Esnek Kapasite ve Üretim Planlama

ABSTRACTINTEGRATED FLEXIBLE CAPACITY ANDINVENTORY MANAGEMENT UNDER FLEXIBLECAPACITY UNCERTAINTYMehmet Fazıl Paş cM.S. in Industrial EngineeringSupervisor: Assist. Prof. Dr. Osman AlpAugust, 2006In a manufacturing environment with volatile demand, inventory managementcan be coupled with dynamic capacity adjustments for handling the fluctuationsmore effectively. In this study we consider the integrated management of inven-tory and flexible capacity management under seasonal stochastic demand anduncertain labor supply. The capacity planning problem is investigated from theworkforce planning perspective. We consider a manufacturing firm that can tem-porarily increase its production capacity by utilizing contingent workers froman external labor supply agency. The uncertainty of contingent capacity arisesfrom the (un)availability of contingent workers, the pool size and the behaviorof the labor supply agency. Using a dynamic programming approach, we formu-late an infinite horizon model determining the optimal levels of permanent andcontracted capacity, in order to minimize the total cost of operations. Withinthe dynamic program, we determine the optimal operational capacity decisions,namely the size of contracted and contingent capacity to be utilized in each pe-riod. The characteristics of the optimal policies are analyzed under an infinitehorizon setting. In addition we consider temporary labor contracts, that diminishthe effects of supply uncertainty on the manufacturer, at a specific contractingcost. Our analysis shows that as the supply uncertainty and/or the expected costof utilizing contingent workers increase, the value of temporary labor contractsalso increase. In contrast increasing demand variability reduces the incentiveof the manufacturer to own capacity and increases the utilization of contingentresources.Keywords: Flexible Capacity, Capacity Management, Inventory, ProductionPlanning, Stochastic Dynamic Programming.iii