I. Introduction
The importance of satisfying the customer by meeting the demand has long been recognized by managers as crucial to making the organization successful. However, numerous problems occur and many factors need to be considered in order to give the customer what they want, how they want it, as well as where and when they want it. Failure to understand crucial characteristics of demand will result in supply shortage or excessive stock that will place serious financial burdens on the organization, subsequently leading to a loss of market share and customers.