The effect of estimated processing times versus actual (standard) processing times on various performance measures in a pure job shop

dc.contributor.authorEmaminezhad, Farzaden
dc.contributor.departmentIndustrial Engineering and Operations Researchen
dc.description.abstractA comparative simulation study was performed to investigate the effect of uncertainty or unreliability in job processing times on designing schedules in a pure job shop environment. Five performance measures were employed in an effort to examine the effect of variations between estimated and actual processing times. These variations are common in job shop systems where estimations are used to set processing times. It was hypothesized that a variation has an effect on relative system performance. In addition, three priority rules, namely, FIFO, SOT and EDD, were studied to determine the best rule for controlling the shop in situations of unreliable processing times data. The percentage variation in processing times was clearly the dominant variable for most of the performance measures. A 60% variation in estimated processing times appeared to be the maximum level under which the mean flowtime, mean tardiness and percent of late jobs performance measures were insensitive. The simulation results indicated that the makespan and average shop utilization performance measures were insensitive to reliability of input information about processing times for up to a 100%. The performance of FIFO and EDD priority rules suffered drastically while SOT was the least sensitive to the reliability of processing times information.en
dc.format.extentx, 124 pages, 2 unnumbered leavesen
dc.publisherVirginia Polytechnic Institute and State Universityen
dc.relation.isformatofOCLC# 09656539en
dc.rightsIn Copyrighten
dc.subject.lccLD5655.V855 1983.E525en
dc.subject.lcshProduction scheduling -- Simulation methodsen
dc.titleThe effect of estimated processing times versus actual (standard) processing times on various performance measures in a pure job shopen
dc.type.dcmitypeTexten Engineering and Operations Researchen Polytechnic Institute and State Universityen
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