A Hybrid SOM-BPN Approach to Lot Output Time Prediction in a Wafer Fab
Neural Processing Letters
An intelligent hybrid system for wafer lot output time prediction
Advanced Engineering Informatics
A look-ahead fuzzy back propagation network for lot output time series prediction in a wafer fab
ICONIP'06 Proceedings of the 13th international conference on Neural information processing - Volume Part III
MICAI'06 Proceedings of the 5th Mexican international conference on Artificial Intelligence
RSCTC'06 Proceedings of the 5th international conference on Rough Sets and Current Trends in Computing
Computers and Industrial Engineering
Applying a Fuzzy and Neural Approach for Forecasting the Foreign Exchange Rate
International Journal of Fuzzy System Applications
Learning Fuzzy Network Using Sequence Bound Global Particle Swarm Optimizer
International Journal of Fuzzy System Applications
International Journal of Fuzzy System Applications
A PCA-FBPN Approach for Job Cycle Time Estimation in a Wafer Fabrication Factory
International Journal of Fuzzy System Applications
Computers and Industrial Engineering
A fuzzy-neural approach for global CO2 concentration forecasting
Intelligent Data Analysis
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Estimating the cycle time of a job in a wafer fabrication plant (wafer fab) is a critical task to the wafer fab. Many recent studies have shown that pre-classifying a job before estimating the cycle time was beneficial to the forecasting accuracy. However, most pre-classification approaches applied in this field could not absolutely classify jobs. Besides, whether the pre-classification approach combined with the subsequent forecasting approach was suitable for the data was questionable. For tackling these problems, two hybrid approaches with example post-classification, the equally-divided method and the proportional-to-error method, are proposed in this study in which a job is post-classified by a back propagation network (BPN) instead after the forecasting error is generated. In this novel way, only jobs whose cycle time forecasts are the same accurate will be clustered into the same category, and the classification algorithm becomes tailored to the forecasting approach. For evaluating the effectiveness of the proposed methodology and to make comparison with some existing approaches, production simulation (PS) is applied in this study to generate test data. According to experimental results, the forecasting accuracy (measured with root mean squared error, RMSE) of the proportional-to-error method was significantly better than those of the other approaches in most cases by achieving a 26-56% (and an average of 41%) reduction in RMSE over the comparison basis - multiple-factor linear combination (MFLC). The effect of post-classification was also statistically significant.