This paper develops simple approximate methods to analyze a two-stage stochastic distribution system consisting of one warehouse and multiple retailers. We consider local and central control schemes. The main ideas are based on relaxing and or decomposing the system into more manageable newsvendor type subsystems. We provide bounds on optimal echelon base-stock levels and on the optimal expecte...

This paper demonstrates optimal policies for capacitated serial multiechelon production/inventory systems. Extending the Clark and Scarf (1960) model to include installations with production capacity limits, we demonstrate that a modified echelon base-stock policy is optimal in a two-stage system when there is a smaller capacity at the downstream facility. This is shown by decomposing the dynam...

The aim of this paper is to give a brief introduction to some recent approaches to timetabling problems that have been developed or are under development in the Automated Scheduling, Optimisation and Planning Research Group (ASAP) at the University of Nottingham. We have concentrated upon university timetabling but we believe that some of the methodologies that are described can be used for dif...

We study the strategic problem of locating tugboats along Norwegian coast to optimize maritime preparedness. The is formulated as a two-stage stochastic program. In first stage, we locate such that nominal coverage requirements are satisfied, whereas deploy located in second stage order assist vessels distress. objective minimize sum costs publicly operated emergency towing service and expected...

This paper considers a three-stage assembly flowshop scheduling problem with sequence-dependent setup < /div> times at the first stage and blocking times between each stage in such a way that the weighted mean completion time and makespan are minimized. Obtaining an optimal solution for this type of complex, large-sized problem in reasonable computational time using traditiona...

The paper considers the 2-stage flow shop problem with parallel dedicated machines. In such a situation, each job can only be processed on a pre specified subset of machines. A mathematical model for this problem is proposed to minimize the maximum completion time among all jobs commonly known as the makespan or the Cmax. Furthermore, two approximate methods are proposed. The first one is a heu...

Traditional optimization techniques such as Dynamic Programming(DP), Linear Programming(LP), and MixedInteger Programming(MIP) have been used to solve complex optimization problems in many diverse fields. Shortcomings of these classical techniques and the rapid development of affordable, powerful computing technology have led to the creation of new classes of heuristic-based optimizing techniqu...

This paper studies a periodic-review, serial inventory system in which echelon r nQ T policies are implemented. Under such a policy, each stage reviews its inventory in every T period and orders according to an echelon r nQ policy. Two types of fixed costs are considered: one is associated with each order batch Q, and the other is incurred for each inventory review. The objective is to find the...