The joint replenishment and delivery scheduling involving multiple suppliers offering different quantity discounts

This paper deals with the joint replenishment and delivery scheduling problem of a warehouse. This problem includes in selecting any suppliers offering different quantity discounts as well as in determining the joint replenishment schedules and the outbound delivery schedules of a warehouse. The objective is to minimize the total relevant cost which is composed of the sum of major and minor ordering costs, inventory holding costs and outbound transportation costs of a warehouse and inventory holding costs of retailers. The mathematical model and the hybrid genetic algorithm are proposed to solve this problem.