Güvenilir olmayan tedarikçi varlığında stok politikalarının analizi

We study a single-product, periodic-review inventory problem where a retailer uses a dual sourcing strategy to cope with potential supply disruptions. A new fixed cost structure is introduced consisting of basic and secondary fixed costs where the former is incurred whenever an order is placed (e.g. administrative costs) and the latter is incurred only when an order is filled (e.g. transportation costs). We analyze two cases: In the first case, one supplier is perfectly reliable with a high unit price, and the other is unreliable with a lower unit price following a Markovian availability structure. Through numerical experiments, the optimal ordering policies are found and characterized using a Markov Decision Process-based characterization procedure. Results show that the structure of the ordering policies follows one of these four cases: case 1: Order only from the unreliable supplier; case 2: Order simultaneously from both suppliers or only from the unreliable supplier depending on the inventory level; case 3: Order from one or the other but not both suppliers simultaneously; and case 4: Order only from the reliable supplier. In the second case, we extend the problem to include two unreliable suppliers, one being more reliable but also more expensive than the other.