MRP in a job shop environment using a resource constrained project scheduling model

One of the most difficult tasks in a job shop manufacturing environment is to balance schedule and capacity in an ongoing basis. MRP systems are commonly used for scheduling, although their inability to deal with capacity constraints adequately is a severe drawback. In this study, we show that material requirements planning can be done more effectively in a job shop environment using a resource constrained project scheduling model. The proposed model augments MRP models by incorporating capacity constraints and using variable lead time lengths. The efficacy of this approach is tested on MRP systems by comparing the inventory carrying costs and resource allocation of the solutions obtained by the proposed model to those obtained by using a traditional MRP model. In general, it is concluded that the proposed model provides improved schedules with considerable reductions in inventory carrying costs.Job shop scheduling Project management Capacity Optimization

Resource-constrained project scheduling: A survey of recent developments

We review recent advances in dealing with the resource-constrained project scheduling problem using an efficient depth-first branch-and-bound procedure, elaborating on the branching scheme, bounding calculations and dominance rules, and discuss the potential of using truncated branch-and-bound. We derive conclusions from the research on optimal solution procedures for the basic problem and subsequently illustrate extensions to a rich and realistic variety of related problems involving activity preemption, the use of ready times and deadlines, variable resource requirements and availabilities, generalized precedence relations, time/cost, time/resource and resource/resource trade-offs and non-regular objective functions. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.status: publishe