ABSTRACT
This chapter deals with an inventory model with ramp-type demand. The application of differential equations comes into play when some variability exists in the phenomena. Basically, in inventory control differential equation appears while dealing with the demand. The rate of demand may be fixed or variable depending on which the governing differential equation changes. On solving the differential equation, a relation between order quantity, time, and demand is obtained, which is further used for the optimization of the objective function (cost or profit). In EOQ and EMQ, the demand rate was considered constant and a simple governing differential equation (ordinary) was developed with two boundary conditions. Later on, the governing differential equation for demand was modified by introducing several variable quantities in demand or by considering inventory deterioration. Underneath are some of the fundamental forms of governing differential equations of inventory control.
