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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean society for quality management
Journal Basic Information
Journal DOI :
The Korean Society for Quality Management
Editor in Chief :
Volume & Issues
Volume 25, Issue 4 - Dec 1997
Volume 25, Issue 3 - Sep 1997
Volume 25, Issue 2 - Jun 1997
Volume 25, Issue 1 - Mar 1997
Selecting the target year
Design of Screening Inspection in a Multi-Stage Manufacturing Systems
Journal of the Korean society for quality management, volume 25, issue 1, 1997, Pages 1~16
In this paper, we illustrate how to design screening inspections for minimizing a total quality costs in a multi-stage manufacturing systems. The total quality cost model consists of inspection costs, internal failure costs, external failure costs, and Taguchi's loss function. Although, the use of automatic test equipment such as machnie vision and CMM has greatly increased inspection speed and accuracy, screeing(100% inspection) could be considered only as a short-term method to remove nonconforming items from a population, not for a long-term quality improvement. However, screeing should be used for certain situations such as before costly operations and after unsatisfied operations. This paper ends with an example that demonstrates the usefulness of the model.
Analysis of Differences Between QS-9000 and ISO 9000
Journal of the Korean society for quality management, volume 25, issue 1, 1997, Pages 17~30
Three big U.S. automakers have developed the QS-9000 quality system for their su, pp.iers. These automakers are requiring their su, pp.iers to implement the QS-9000 based quality system. This QS-9000 system is based upon the ISO 9000 series quality systems. This paper describes the differences between the ISO 9000 series requirements and the QS-9000 requirements. It also suggests the way to implement the QS-9000 quality systems for Korean su, pp.iers.
A Comparison Between TPM and RCM on the Maintenance Planning
Journal of the Korean society for quality management, volume 25, issue 1, 1997, Pages 31~43
In this study, the pros and cons of TPM and RCM were comparatively evaluated at various aspects : a, pp.ication process, objectives, maintenance items, organizations, analysis of maintenace methods, etc. It is found that TPM can be considered as a management discipline. However, in TPM, there seldom exist concrete rules or guidelines to select a maintenance scheme. RCM, which is a widely used maintenance scheme for aircrafts or power plants, has a good analysis and decision logic for maintenance planning. In the paper, similar decision rules are adopted to TPM deployment to get an effective and effecient maintenance Planning.
A Study on the Analysis Procedures of Nonlinear Growth Curve Models
Journal of the Korean society for quality management, volume 25, issue 1, 1997, Pages 44~55
In order to determine procedures for a, pp.opriate model selection of technological growth curves, numerous time series that were representative of growth behavior were collected according to data characteristics. Three different growth curve models were fitted onto data sets in an attempt to determine which growth curve models achieved the best forecasts for types of growth data. The analysis of the results gives rise to an a, pp.oach for selecting a, pp.opriate growth curve models for a given set of data, prior to fitting the models, based on the characteristics of the goodness of fit test.
Simultaneous Optimization of Multiple Responses Using Weighted Desirability Function
Park, Sung-Hyun ; Park, Jun-Oh ;
Journal of the Korean society for quality management, volume 25, issue 1, 1997, Pages 56~68
The object of multiresponse optimization is to determine conditions on hte independent variables that lead to optimal or nearly optimal values of the response variables. Derringer and Suich (1980) extended Harrington's (1965) procedure by introducing more general transformations of the response into desirability functions. The core of the desirability a, pp.oach condenses a multivariate optimization into a univariate one. But because of the subjective nature of this a, pp.oach, inexperience on the part of the user in assessing a product's desirability value may lead to inaccurate results. To compensate for this defect, a weighted desirability function is introduced which takes into consideration the vriances of the responses.
Small-Sample Inference in the Errors-in-Variables Model
Journal of the Korean society for quality management, volume 25, issue 1, 1997, Pages 69~79
We consider the semiparametric linear errors-in-variables model: yi=(
i=1, …, n where (xi, yi) stands for an observation vector, (ui) denotes a set of incidental nuisance parameters, (
) is a vector of regression parameters and (
) are mutually uncorrelated measurement errors with zero mean and finite variances but otherwise unknown distributions. On the basis of a simple small-sample low-noise a, pp.oximation, we propose a new method of comparing the mean squared errors(MSE) of the various competing estimators of the true regression parameters ((
). Then we show that a class of estimators including the classical least squares estimator and the maximum likelihood estimator are consistent and first-order efficient within the class of all regular consistent estimators irrespective of type of measurement errors.
Designs and Comparison of Step and Constant-Stress ALTs for Acceleration Factor and Lognormal Lifetime Distributions
Sang Wook Chung ; Seong-Woog Lee ;
Journal of the Korean society for quality management, volume 25, issue 1, 1997, Pages 80~99
This paper considers designing the simple (2-level) constant-and step-stress ALTs minimizing the asymptotic variance of the maximum likelihood estimator of the accelaeration factor, which is defined as the ratio of the 100qth percentile at use stress to that a specified stress, for items having lognormally-distributed lives. It is assumed that (i) the log-linear relationship exists between the stress and the mean log life, (ii) the standard deviation of the log life is constant, and (iii) the cumulative exposure model holds for the effect of changing stress. For the constant-stress ALT the low stress and the sample proportion allocated to low stress are determined and for two modes of stress loading of step-stress ALTs, the low-to-high and high-to-low, the low stress and the stress change time are determined. For selected values of the design parameters the optimum plans are figured, two modes of step-stress ALTs and the constant-stress ALT are compared to each other, and the effects of the incorrect pre-estimates of the design parameters are investigated.
Control Charts Based on Self-critical Estimation Process
Won, Hyung-Gyoo ;
Journal of the Korean society for quality management, volume 25, issue 1, 1997, Pages 100~115
Shewhart control chart is a basic technique to monitor the state of a process. We observe samples of size four or five and plot some statistic(e.g., mean or range) of each sample on the chart. When setting up the chart, we need to obtain u, pp.r and lower control limits. It is common practice that those limits are calculated from the preliminary 20-40 samples presumed to be homogeneous. However, it may ha, pp.n in practice that the samples are contaminated by outlying observations caused by various reasons. The presence of outlying observations make the control limits wider and hence decrease the sensitivity of the charts. In this paper, we introduce robust control charts with tighter control limits when outlying observations are present in the preliminary samples. Examples will be given via simulation study.
Real Time Process Control System under 100 PPM Management System
Journal of the Korean society for quality management, volume 25, issue 1, 1997, Pages 116~134
The present automated manufacturing environment is very different when the classical statistical process control method based on batch processing were used. Therefore these must be replaced by automated statistical process control method. In this point of view, this paper intends to develop the automated statistical process control method which can be implemented in the present automated manufacturing environment. Specially this study developed the rules to identify the special causes of the manufacturing process in the aspect of the 100 PPM management, and a numerical example is demonstrated to verify the usefulness of these rules.
A Test on Quality Improvement of Printed Circuit Board Using Mold Compensation
Journal of the Korean society for quality management, volume 25, issue 1, 1997, Pages 135~141
The Copper-Clad Laminate (CCL) is a main electronic component of specialtype printed circuit boards (PCBs) such as Silver Through Hole PCB. This CCL should have high reliability under the aging test, and usually the test is done at a higher temperature (110-
) than the normal. Then, this test condition of high temperature may cause such quality problems as hole eccentricity and reduction of distance between part holes. After measuring the CCL shrinkage affected by temperature, the correction factor of a press mold was a, pp.ied to solve these problems. The results showed that the tolerance of hole pitch(
) was satisfactory and the internal and external failure costs were reduced by 55%.
A Development Methodology for Quality Assurance System in Large-Scale Software Development Project
Journal of the Korean society for quality management, volume 25, issue 1, 1997, Pages 142~155
To successfully carry out large scale research projects while su, pp.rting quality assurance of research output, effective and systematic management through utilization of resources such as manpower, time and cost as well as engineering techniques such as component technology and design methodology is required. It is necessary to establish development methodology to su, pp.rt quality assurance. The development methodology covers the contents and procedures of the project, such as division of the project into independently executable units, allocation of resources including researchers, component technology, related know-how and equipment, deployment of research units and integration of the project at the end. In this paper we present systematic development methodology for quality assurance in large scale software development projects by analyzing the contents of the methodology a, pp.ied to the Gigabit Information-processing And Networking Technology development project(GIALT).
How to Perform FMEA Effectively
Journal of the Korean society for quality management, volume 25, issue 1, 1997, Pages 156~172
FMEA is a widely used technique to assess or to improve reliability of products at early stage of design and development. In order to implement FMEA effectively, it is important to utilize knowledge or technical know-hows. However, that is very difficult. In fact, if information on the failure modes is enough, it is important to consider a counterplan to eliminate critical failure modes. If engineers do not have such information, however, it is more important to know what failure modes of the component under consideration would undergo. This means that the purposes of performing FMEA varies according to the situation. Therefore, we need different kinds of FMEA charts to meet those purposes. This paper proposes two FMEA charts: one is suitable for detecting potential failure modes and the other is for product improvements.
Determination of the Modified Periodic Inspection Policy Using Nonparametric Appoximation
Journal of the Korean society for quality management, volume 25, issue 1, 1997, Pages 173~181
A modified periodic inspection policy is examined. It is troublesome to know the life distribution and burdensome to compute an optimum planned inspection time numerically as well. A nonparametric a, pp.oximation is used so that equations for the optimum inspection time are expressed as closed forms. To show that the a, pp.oximation can be used in practice, simulations are conducted in the case of Weibull failure times.
Development of Probability Computation Program for Standard Normal Distribution
Journal of the Korean society for quality management, volume 25, issue 1, 1997, Pages 182~192
The well-known standard normal distribution has been used within the limit of standard variable value of u=3.59. However, the probability values above the limit are not given in the literature. In this study, a probability computation program for standard normal distribution to u=5.99 with the proportional normal distribution a, pp.oximation suggested by Abramowitz and Stegun, Hastings is developed. The new standard normal distribution table developed by the program is presented and will be of help to estimate of probability values for testing and estimation of process mean value, lot acceptable probability, defective percentage of PPM unit of an out-of specification limit, process capability, test power of control charts, probability and statistics.
A Comparison on Confidence Intervals for P(X>Y) with Explanatory Variables
Lee, In-Suk ; Cho, Jang-Sik ;
Journal of the Korean society for quality management, volume 25, issue 1, 1997, Pages 193~203
In this paper, we obtain some a, pp.oximate confidence intervals for the reliability of the stress-strength model when the stress and strength each depend on some explanatory variables, respectively. Also we compare the confidence intervals via Monte Carlo simulation.