Constraint-Based Reactive Rescheduling in a Stochastic Environment.

The problem of scheduling manufacturing systems where the capacity of a production resource is subject to stochastic change, is the subject of this paper. Resources which are dependent upon labour intensive processes provide typical examples. In the United Kingdom the manufacture of clothing garments is still dominated by the progressive bundle system. Garments are produced on a continuous-flow production line in which garment pieces are passed in succession through a network of workstations where skilled manual workers complete operations on garments using sewing machines. These production systems are subject to numerous perturbations caused by operator absenteeism and machine breakdown necessitating the need for reactive rescheduling to maintain line balance. In the approach described here, line balance is maintained via periodic schedule repair, based upon reassignment heuristics, supported by partial order backtracking

A Generic Mechanism for Repairing Job Shop Schedules

Reactive repair of a disrupted schedule is a better alternative to total rescheduling, as the latter is a time consuming process and also results in shop floor nervousness. The schedule repair heuristics reported in the literature generally address only machine breakdown. This paper presents a modified Affected Operations Rescheduling (mAOR) approach, which deals with many of the disruptions that are frequently encountered in a job shop. The repair of these disruptions has been decomposed into four generic repair actions that can be applied singularly or in combination. These generic repair actions are evaluated through a simulation study with the performance measures of efficiency and stability. The results indicate the effectiveness of the mAOR heuristic in dealing with typical job shop disruptions.Singapore-MIT Alliance (SMA

Scheduling of crude oil and product blending and distribution operations in a refinery

Ph.DDOCTOR OF PHILOSOPH

Constraint Based Reactive Rescheduling in a Stochastic Environment

The problem of scheduling manufacturing systems where the capacity of a production resource is subject to stochastic change, is the subject of this paper. Resources which are dependent upon labour intensive processes provide typical examples. In the United Kingdom the manufacture of clothing garments is still dominated by the progressive bundle system. Garments are produced on a continuous-flow production line in which garment pieces are passed in succession through a network of workstations where skilled manual workers complete operations on garments using sewing machines. These production systems are subject to numerous perturbations caused by operator absenteeism and machine breakdown necessitating the need for reactive rescheduling to maintain line balance. In the approach described here, line balance is maintained via periodic schedule repair, based upon reassignment heuristics, supported by partial order backtracking