QUALITY DESIGN OF TAGUCHI’S DIGITAL DYNAMIC SYSTEMS

Taguchi’s method is a widely employed methodology in many different industries for improving product quality and process performance. Digital dynamic systems denote the problems where both the input and output are digital values in Taguchi’s method. When the signal factor levels are classified into two classes and the output is classified into two or more classes, two or more errors will occur in experiments. The digital dynamic systems are widely applied in the fields of telecommunication, computer operations, chemistry and tests of detection of medicine or environmental pollution. The SN ratio recommended by Taguchi is based on the errors with the same loss coefficient to optimize the problems. However, the losses due to the errors are not equal in practice. This paper proposes a general model for optimizing parameter design and selecting threshold value for the digital dynamic systems where the output is classified into four classes. The implementation and the effectiveness of the proposed approach are illustrated through two case studies

Simultaneous Optimization of Robust Design with Quantitative and Ordinal Data

The Taguchi method traditionally focused on one quality characteristic to optimize the control factor settings, yet most products have more than one quality characteristic. Several studies have presented approaches optimizing the multiple quantitative quality characteristics design. Due to the inherent nature of the quality characteristic or the convenience of the measurement technique and cost-effectiveness, the data observed in many experiments are ordinal data. Few published articles have focused primarily on optimizing the multiple quality characteristics involving quantitative and ordinal data. This paper presents a simple approach to optimizing this problem based on the quality loss function. A numerical example of the polysilicon deposition process for minimizing surface defects and achieving the target thickness in a very large-scale integrated circuit can demonstrate the proposed approach’s effectiveness