2.3. Inventory models with variable demand and variable holding cost
In several models in which both the holding cost and the demand rate are variable, the demand rate is assumed stock dependent.
Alfares (2007) proposed an EOQ-based model with stock-level dependent demand rate, where the holding cost increases either retroactively or incrementally with longer storage times.
Alfares (2014) extended this model to an EPQ model, with finite production rate, non-zero starting inventory, and profitmaximization objective. Zhao and Zhong (2008) modified the model of Alfares (2007) by assuming the holding cost to be a decreasing function of the storage time. Pando, García-Laguna, San-José, and Sicilia (2012) studied an EOQ model in which the demand rate and the holding cost depend on the stock level.
Pando, San-José, García-Laguna, and Sicilia (2013) maximized the total profit for an inventory model with inventory leveldependent demand. The holding cost was assumed a non-linear function of both the storage time length and the inventory level. Several inventory models considered demand dependence on other factors such as the product selling price and quality.
Datta (2013) analyzed an inventory model assuming that the demand depends on both the quality and the selling price of the products.
Kumar, Chauhan, and Kumar (2013) studied an EOQ model under the assumption of price-dependent demand, where the holding cost is a time-function of the trade credit for deteriorating items.
Datta and Paul (2001) studied a similar EOQ model assuming the demand rate depends on both the inventory stock and the price of the item, while the holding cost varies with the storage time.