Knowledge that Transforms

This paper compares several different production control policies in terms of their robustness to random disturbances such as machine failures, demand fluctuations, and system parameter changes. Simulation models based on VLSI wafer fabrication facilities are utilized to test the performance of the policies. Three different criteria, namely, the average total WIP, the average backlog, and a cost function combining these measures, are used to evaluate performance. Among the policies tested, the Two‐Boundary Control policy outperforms the others.

In this article we pass on advice for getting through a dissertation that we found useful in our roles as dissertation advisors and doctoral students. We have also included some other hints on starting and getting through a doctoral program, as well as beginning an academic career. We hope that readers in a position to advise Ph.D. students will convey the recommendations stated here to their students. Since the final responsibility for completing the degree rests with the student, the advice given here is, by and large, addressed directly to students and can be passed on to them in its current form.

The future of the global industry lies in the continuous improvement of both products and processes, a renewed commitment to competition, and an aggressive approach to satisfying customers needs in quality, quantity, and timing. In quality management, the degree of customer satisfaction for a given product may be measured in the form of the loss to society. This loss is formulated as a function of the deviation from the target for each of the product's quality characteristics. The greater the variability of uncontrolled factors during manufacturing or production the larger will be that loss. In this paper, we develop a form of the loss function that takes into account the variability of a production process, the decision loss, and the costs of sampling and inspection. Specifically, we consider monitoring a production process, which may undergo continuous mean shift and variance deterioration during a production run. We then examine decision rules for continuing production or stopping and adjusting the production process.

This research investigated the value of protecting the continuity of release batchs in a transfer batching environment, by modifying the SPT rule. A simulation model of a job shop was used to test the modified SPT rule. The performance measures evaluated were mean flow time, flow time variance, and mean lateness. Conditions under which the SPT modification improved results were as follows: large number of transfer batches, small setup time to process time ratio, and large variation in process times from station to station. The results suggest that shop loading is not a significant factor affecting performance of the modified SPT rule.

In this paper we study the time complexities of some two‐ and three‐stage no‐wait flowshop makespan scheduling problems where, in some stage, all the jobs require a constant processing time and the stage may consist of parallel identical machines. Polynomial time algorithms are presented for certain problems, while several others are proved to be strongly NP‐complete.

This paper compares flexible automation with labor‐intensive manufacturing processes in a batch production environment and considers learning, forgetting, inventory carrying costs, setup costs, production demand volume, previous production experience, and the proportion of material to labor cost. While flexible automation typically can reduce setup times, and therefore inventory carrying costs through smaller optimal batch sizes, the results of this research show that the effect of forgetting on relative cost savings is difficult to predict in some situations. When using optimal lot sizes in both the automated and labor environments, cost savings from flexible automation may be smaller than expected or may occur in different ways than anticipated.

Siemens Brief Case Game Supply Chain Simulator provides a practical setting for experiential learning exercises about supply chains. The game, drawing upon an actual situation, models the jobs of nine supply chain activities required to transform an order placed by the customer into a delivered product. Using the detail and complexity of the game, instructors can develop learning exercises that focus on a wide range of supply chain management issues. This paper describes two learning exercises with different objectives and for different audiences that we successfully delivered using the Brief Case Game. One exercise provides a concrete example of typical activities in a supply chain and their interactions. The other exercise leads students to discover what creates a need for coordination, what activities in a supply chain require coordination, and what methods work well. These exercises are suited for small upper level undergraduate and graduate courses in logistics and supply chain management. While significant resources were used to develop exercises and deliver the game, students were enthusiastic about the approach and demonstrated that they learned about the complexity inherent in managing supply chains.

This paper describes the supply chain tour, an expansion of the widely used facility tour pedagogy. A supply chain tour is a tour of facilities sequentially related in the creation of value that is designed to expose critical linkages and illustrate Supply Chain Management concepts and theories. Effectively using the supply chain tour pedagogy requires the instructor to create a standardized approach to managing the facility tour; a checklist is provided for this purpose. An example supply chain tour, used in the author's classes, is described.

This paper discusses four experiments and experiences with the use of supply chain management software, in this case the CAPS Logistics software, at different levels of undergraduate and graduate education at the School of Industrial and Systems Engineering at the Georgia Institute of Technology. We hope that the readers will get an idea of the commitment and resources necessary to integrate supply chain software into the classroom as well as the potential rewards.

This paper explores the effect that unions have on a firm's ability to reengineer manufacturing processes. We begin by exploring the various effects that a union may have in a manufacturing environment. Next, we briefly review how unions may affect managerial initiatives to reengineer processes and improve manufacturing performance. The third section analyzes an existing database to test for differences in cycle time and manufacturing performance between union and nonunion firms. Finally, we discuss the implications of the study for future operations strategy research and note how a different form of union‐management relationships is beginning to evolve.