• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2004.10a
• /
• pp.92-96
• /
• 2004

In this paper, polishing method using bonded magnetic abrasive particle has been applied to the micro mold polishing. Through process control using the Run-to-Run control, it tried to form the surface roughness In order to grasp the influence of the surface roughness which is reached by selection of control factor and the factor, a design of experiment was been processed. The study is processed with a purpose of to embody and to maintain the surface roughness of nano scale by the basis of an influence between a control factor and the factors which has been selected in this way. As a result, the result of the process control converged at a target value of surface roughness Ra 10nm and Rmax 50nm

• Journal of Institute of Control, Robotics and Systems
• /
• v.6 no.1
• /
• pp.104-111
• /
• 2000

A fuzzy logic Run-by-Run(RbR) controller and an in -line wafer characteristics prediction scheme for the rapid thermal processing system have been developed for the study of process repeatability. The fuzzy logic RbR controller provides a framework for controlling a process which is subject to disturbances such as shifts and drifts as a normal part of its operation. The fuzzy logic RbR controller combines the advantages of both fuzzy logic and feedback control. It has two components : fuzzy logic diagnostic system and model modification system. At first, a neural network model is constructed with the I/O data collected during the designed experiments. The wafer state after each run is assessed by the fuzzy logic diagnostic system with featuring step. The model modification system updates the existing neural network process model in case of process shift or drift, and then select a new recipe based on the updated model using genetic algorithm. After this procedure, wafer characteristics are predicted from the in-line wafer characteristics prediction model with principal component analysis. The fuzzy logic RbR controller has been applied to the control of Titanium SALICIDE process. After completing all of the above, it follows that: 1) the fuzzy logic RbR controller can compensate the process draft, and 2) the in-line wafer characteristics prediction scheme can reduce the measurement cost and time.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.18 no.1
• /
• pp.22-28
• /
• 2009

In order to optimize the polishing process, Run to Run control scheme has been applied to the micro mold polishing in this study. Also, to fully understand the effect of parameters on the surface roughness a design of experiment is performed. By linear approximation of main factors such as gap and rotational speed of micro quill, EWMA (Exponential Weighted Moving Average) gradual mode controller is adopted as a optimizing tool. Consequently, the process converged quickly at a target value of surface roughness Ra 10nm and Rmax 50nm, and was hardly affected by unwanted process noises like initial surface quality and wear of magnetic abrasives.

• Journal of the Korea Safety Management & Science
• /
• v.12 no.4
• /
• pp.255-263
• /
• 2010

The research developes short-run standardized control charts(SSCC) and short-run acceptance control charts(SACC) under the various demand patterns. The demand patterns considered in this paper are three types such as high-variety and repetitive low-volume pattern, extremely-high-variety and nonrepetitive low-volume pattern, and high-variety and extremely-low-volume pattern. The short-run standardized control charts developed by extending the long-run ${\bar{x}}$-R, ${\bar{x}}$-s and I-MR charts have strengths for practioners to understand and use easily. Moreover, the short-range acceptance control charts developed in the study can be efficiently used through combining the functions of the inspection and control chart. The weighting schemes such as Shewhart, moving average (MA) and exponentially weighted moving average (EWMA) can be considered by the reliability of data sets. The two types according to the use of control chart are presented in the short-range standardized charts and acceptance control charts. Finally, process capability index(PCI) and process performance index(PPI) classified by the demand patterns are presented.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.10a
• /
• pp.85-85
• /
• 2003

• Journal of Korean Society for Quality Management
• /
• v.38 no.2
• /
• pp.190-201
• /
• 2010

This research proposes a method for designing VSI (Variable Sampling Interval) control charts with supplementary run rules. The basic idea is to apply various run rules and the VSI scheme to a control chart in order to increase the sensitivity. The sampling process of the VSI run rules chart is constructed by Markov chain approach. A procedure for designing the VSI run rules chart is proposed based on Lorenzen and Vance's model. Sensitivity study shows that the VSI run rules charts outperform the FSI (Fixed Sampling Interval) run rules charts for wide range of process mean shifts. A major advantage of the VSI run rules chart over other charts such as CUSUM, EWMA, and adaptive charts is it's simplicity in implementation. Some useful guidelines are proposed based on the sensitivity study.

• Journal of Veterinary Clinics
• /
• v.15 no.2
• /
• pp.279-290
• /
• 1998

The diagnosis of canine diabetes mellitus is generally made by measuring serum fructosamine levels. The Rosental's end points Tas and El Din's kinetic, and Johnson and colleagues'kinetic techiniques were compared for the measuring serum fructosamine levels. In the Rosental's end point methods within-run and between-run coefficient of variability (CV) were 2.4-3.5% and 6.8-8.5%, respectively, and in the Tas and El Din's kinetic method, within-run and between-run CV were 1.3-3.0% and 3.4-3.9%, respectively. In the Johnson and colleagues'kinetic methods within-run and between-run CV were 0-1.8% and 3.1-6.8%1 ruts- pectively. Hyperlipidemia induced by oral administration of 3 ml of corn oil per kilogram body weight did not affect serum fructosamine concentration significantly in the Johnson and colleagues' kinetic method Johnson and colleagues'kinetic method is most reliable and consistant on the basis of comparison study.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.22 no.4
• /
• pp.145-151
• /
• 2014

Modern vehicle has a lot of ECU(Electronic Control Unit) products to control many parts such as engine, transmission, brake, body and so on. ECU quality is one of important factors related to vehicle quality and driver's safety. Based on Bath-tub curve which presents failure rate during product lifetime, we designed and applied Accelerated Run-in Test into manufacturing line by simulating stress amount to ECU and developing the required software and efficient test equipment for mass production. This test makes ECU products stressed through electrical and thermal stresses under excessive driving condition, which induce potential initial failure of components in the ECU during production. The outcome until these days proved that Acceleration Run-in Test have reduced initial failure rates and increased quality of ECU products in the field outstandingly.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.61 no.9
• /
• pp.1283-1288
• /
• 2012

This paper presents speed control characteristics of capacitor-run SPIM(Single Phase Induction Motor) using TRIAC for comparing and analyzing four kinds of voltage control methods such as supply voltage control, main winding voltage control, auxiliary winding voltage control and auxiliary winding voltage control without starting capacitor. The computer simulations were performed using MATLAB Simulink to show control characteristics of four voltage control methods. And their control characteristics were conformed by experiments for capacitor-run 90W SPIM as a sample motor. The results of simulations and experiments show that supply voltage control method has fast dynamic response characteristics and main winding voltage control method has higher power efficiency and can be implemented at lower system cost.

• Industrial Engineering and Management Systems
• /
• v.9 no.3
• /
• pp.262-274
• /
• 2010

This article investigates how to adaptively predict the time-varying metrology delay that could realistically occur in the semiconductor manufacturing practice. Metrology delays pose a great challenge for the existing run-to-run (R2R) controllers, driving the process output significantly away from target if not adequately predicted. First, the expected asymptotic double exponentially weighted moving average (DEWMA) control output, by using the EWMA and recursive least squares (RLS) prediction methods, is derived. It has been found that the relationships between the expected control output and target in both estimation methods are parallel, and six cases are addressed. Within the context of time-varying metrology delay, this paper presents a modified recursive least squares-linear trend (RLS-LT) controller, in combination with runs test. Simulated single input-single output (SISO) R2R processes subject to various time-varying metrology delay scenarios are used as a testbed to evaluate the proposed algorithms. The simulation results indicate that the modified RLS-LT controller can yield the process output more accurately on target with smaller mean squared error (MSE) than the original RLSLT controller that only deals with constant metrology delays.