Developing and Fitting a Clearing Function Form: An Experimental Comparison of A Clearing Function Model and Iterative Simulation-Optimization Algorithm for Production Planning of a Semiconductor Fab
Kacar, Necip Baris. Developing and Fitting a Clearing Function: An Experimental Comparison of A Clearing Function Model and Iterative Simulation-Optimization Algorithm for Production Planning of a Semiconductor Fab. (Under the direction of Professor Reha Uzsoy).
We address the fundamental problem of workload â dependent lead times in production planning, known as planning circularity. We focus on a clearing function model and iterative algorithm that addresses planning circularity. We develop a clearing function form that expresses output as a function of the sum of the work released within a period plus any work available at the start of the period. We develop a new clearing function form which is different from the clearing functions based on expected WIP over the period that have been previously studied. We implement our clearing function form in the Allocated Clearing Function (ACF) model of (J. M. Asmundsson, Rardin, R. L., Uzsoy, R., 2002) and compare its performance to that of the Hung and Leachman (HL) procedure which is an iterative algorithm that combines simulation and fixed lead time LP models. In our experimental comparison, we use a simulation model of a re-entrant bottleneck system built with attributes of a real-world semiconductor fabrication environment. We vary the bottleneck utilization, demand patterns, the mean time to failure (MTTF) and mean time to repair (MTTR). Results indicate that the ACF model using our clearing function form performs better than HL procedure, giving less variable production plans and lower discrepancies between the planned and realized output.
Advisor:Brian Denton; Yahya Fathi; Reha Uzsoy
School:North Carolina State University
School Location:USA - North Carolina
Source Type:Master's Thesis
Date of Publication:04/13/2009