Search

This paper describes an approximate analytical method for evaluating the average values of throughput and buffer levels of closed three-machine production systems with finite buffers. The method includes a new set of decomposition equations and a new building block model. The machines have deterministic processing times and geometrically distributed probabilities of failure and repair. The numerical results of the method are close to those from simulation. The method performs well because it takes into account the correlation among the numbers of parts in the buffers. Extensions to larger systems are discussed. [Supplementary materials are available for this article. Go to the publisher's online edition of IIE Transactions for the following free supplemental resource: Appendix of additional numerical results] [ABSTRACT FROM AUTHOR]

This paper focuses on the development of an integrated short-term production scheduling simulation model for a complex manufacturing operation. The decision making tool has a front-end user data interface built with Microsoft Access and Visual Basic for Applications software. The model assists production planners to make informed decisions on how best to schedule simultaneously two lanes of daily or weekly production on a unique plastic parts manufacturing line. The advantages and disadvantages (model weaknesses) of using the simulation model, especially as a scheduling tool, are discussed. In this particular application, we find that the advantages far outweigh the disadvantages. [ABSTRACT FROM AUTHOR]

Aggregate models of detailed scheduling problems are needed to support aggregate decision making such as customer order acceptance. In this paper, we explore the performance of various aggregate models in a decentralized control setting in batch chemical manufacturing (no-wait job shops). Using simulation experiments based on data extracted from an industry application, we conclude that a linear regression based model outperforms a workload based model with regard to capacity utilization and the need for replanning at the decentralized level, specifically in situations with increased capacity utilization and/or a high variety in the job mix. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to evaluate scheduling policies for the production of assembled products in an assembly shop. The scheduling policies examined include duedate assignment, labor assignment and item sequencing rules. The sensitivity of these rules to product structure is also considered. The data for analysis is generated by a SLAM II simulation model of a hypothetical dual constrained assembly shop operation. The 2 · 3 · 3 · 3 complete factorial experiment is analyzed by an ANOVA procedure to statistically determine whether job structure, duedate assignment rule, labor assignment rule and item sequencing rule or their interaction significantly affect the root mean square of tardiness of jobs completed by the assembly shop. Further analysis to identify where significant differences in performance occurs is conducted via Tukey multiple comparison tests and general linear contrasts. [ABSTRACT FROM AUTHOR]

In this paper an analytical approximation for the performance of non-homogenous asynchronous Flow Production Systems (FPSs) with finite buffers is presented. Generally distributed stochastic processing times as well as breakdowns and imperfect production are considered. The procedure explicitly accounts for simultaneous blocking and starving. The approximation is based on the decomposition of an M-station-line into M -- 1 two-station-lines which are analyzed with the help of a GI/G/ I /Nmax queueing model. Numerical comparisons with exact and simulation results for hypothetical as well as for real-life flow-lines indicate that the procedure provides accurate results. [ABSTRACT FROM AUTHOR]