In this paper, we have studied some memory dependent Economic order quantity models as the memory effect has an important role to handle the business policy of the inventory system. Demand of a company product depends on many factors like behavior of staff, environment of the shop, product quality etc which are the main reasons of memory effect on the system. Once the customers gain some poor experience, further they will never purchase products from those companies or shop. So inclusion of memory effect in the inventory model is necessary to handle practical business policy. One of the best way of inclusion of memory effect in the EOQ model is the use of fractional calculus as fractional derivative is defined in terms of integration where the limits of integration are the initial state and current state. Three fractional order models have been developed considering (i) only the rate of change of the inventory level of fractional order (ii) demand rate as a fractional polynomial of degree 2, where is the rate of change of the inventory level (iii) demand rate as a fractional polynomial of degree 2m , where m may be different from the order of the rate of change of the inventory level.Here fractional order is physically treated as an index of memory. To develop the models here Caputo type fractional derivative has been applied. Due to solve those problems, we have used primal geometric programming method and finally some numerical examples are cited to establish the memory effect. Our investigation establishes the existence of memory effect on inventory management through fractional formulation of EOQ models which can never be obtained from classical calculus.
Keywords: Fractional order derivative; Memory dependent derivative; Fractional Laplace transform method; Classical inventory model; Fractional order inventory models 798 Rituparna Pakhira et al.