Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/27668
Title: Reactive repair of job shop schedules
Authors: AMRITPAL SINGH RAHEJA
Keywords: Reactive Repair, Job Shop Schedule
Issue Date: 12-Mar-2004
Source: AMRITPAL SINGH RAHEJA (2004-03-12). Reactive repair of job shop schedules. ScholarBank@NUS Repository.
Abstract: The research on job shop scheduling has primarily focused on the predictive schedules that generate a job allocation sequence on machines. When the job shop experiences either external (e.g. unexpected arrival of urgent jobs) or internal disturbances (e.g. machine breakdowns), frequent deviations from the predictive schedule occur. With such disruptions, the schedule becomes ineffective. Reactive schedule repair is an approach that salvages the schedule from these disruptions during online execution. However, the existing schedule repair methods are still in their infancy and have limitations in terms of the repair and the type of disruptions that can be repaired.This thesis has concentrated on heuristic based schedule repair, as these methods are popular and easier to implement on the shop floor. Existing approaches for schedule repair consists of Right Shift Rescheduling (RSR), and Affected Operation Rescheduling (AOR). Both approaches have been used for repairing a single disruption, in particular, machine breakdown. In its present form, neither of the heuristics are capable of handling complicated disruptions that exist in the job shops. In this thesis, an attempt has been made to overcome the inadequacies of heuristic based repair methods. The typical job shop disruptions are studied and their repair processes are decomposed into a few generic repair steps. A new heuristic is proposed in this thesis known as the modified AOR (mAOR). This new heuristic is capable of handling random and multiple disruptions spread over the length of the schedule. The mAOR heuristic has been thoroughly evaluated using simulation, for repair of various singular and multiple complex disruptions. Extensive experimentation has been conducted to investigate the performance of the mAOR heuristic under typical shop floor conditions and has been found to be superior to existing schedule repair heuristics.
URI: http://scholarbank.nus.edu.sg/handle/10635/27668
Appears in Collections:Master's Theses (Open)

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Reactive_repair_of_Job_Shop_Schedule.pdf2.02 MBAdobe PDF

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01_Summary.pdf43.55 kBAdobe PDF

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02_Acknowledgment.pdf40.02 kBAdobe PDF

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03_TableofContent.pdf23.48 kBAdobe PDF

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04_Nomenclature.pdf44.19 kBAdobe PDF

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05_List_fo_Figures.pdf14.72 kBAdobe PDF

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06_List_of_Tables.pdf11.82 kBAdobe PDF

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07_Chapter_1__Introduction.pdf111.77 kBAdobe PDF

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08_Chapter_2__Schedule_Repair.pdf136.31 kBAdobe PDF

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09_Chapter_3__The_mAOR_Heuristics.pdf208.39 kBAdobe PDF

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