• Proceedings of the Korean Society for Quality Management Conference
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• 2004.04a
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• pp.413-418
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• 2004

The bounded adjustment is known to be more efficient than repeated adjustment when the cost is incurred for engineering process control. The procedure of the bounded adjustment is to adjust the process when the one-step predicted deviation exceeds the adjustment limit by the amount of the prediction. In this paper, two run rules are proposed and studied in order to improve the efficiency of the traditional bounded adjustment procedure. The efficiency is studied in terms of the standardized cost through Monte Carlo simulation when the procedure is operated with and without the run rules. The adjustment procedure operated with run rules turns out to be more robust for changes in the process and cost parameters. The Markov chain approach for calculating the properties of the run rules is also studied.

• Journal of Korean Society for Quality Management
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• v.26 no.1
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• pp.143-160
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• 1998

This article is concerned with the selection of subsets of predictor variables to be included in bulding the binary response logistic regression model. It is based on a Bayesian aproach, intended to propose and develop a procedure that uses probabilistic considerations for selecting promising subsets. This procedure reformulates the logistic regression setup in a hierarchical normal mixture model by introducing a set of hyperparameters that will be used to identify subset choices. It is done by use of the fact that cdf of logistic distribution is a, pp.oximately equivalent to that of $t_{(8)}$/.634 distribution. The a, pp.opriate posterior probability of each subset of predictor variables is obtained by the Gibbs sampler, which samples indirectly from the multinomial posterior distribution on the set of possible subset choices. Thus, in this procedure, the most promising subset of predictors can be identified as that with highest posterior probability. To highlight the merit of this procedure a couple of illustrative numerical examples are given.

• Proceedings of the Korean Society for Quality Management Conference
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• 2006.04a
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• pp.325-329
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• 2006

In this paper, the Bayesian procedure for the multiple test of fraction nonconforming, p, is proposed. It is the procedure for checking whether the process is out of control, in control, or under the permissible level for p. The procedure is as follows: first, setting up three types of models, $M_1:p=p_0,\;M_2:pp_0$, second, computing the posterior probability of each model. and then choosing the model with the largest posterior probability as a model most fitted for the observed sample among three competitive models. Finally, the simulation study is performed to examine the proposed method.

• Health Policy and Management
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• v.15 no.4
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• pp.26-45
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• 2005

The purposes of this study were to Identify the .level of measurement on quality Indicators and evaluate the existing indicators in order to determine the priority of quality indicators' application in Korean general hospitals. A survey was conducted using a questionnaire. The subjects were quality managers working at general hospital having over 300 beds. The criteria were relevance, reliability, precision, impact, application, and preference to evaluate quality indicators. According to these six criteria, each indicator was evaluated on a five point scale(5: excellent, 1: poor). The response rate was $40.4\%$. The hospitals have monitored the average of 3.8 indicators(median 4). The indicators such as return to operating room, unplanned readmission, cancellation of booked operations, death, hospital infection, cesarean section rate, volume per disease or procedure, readmission, re-operation, blood transfusion, and post-procedural complications were frequently measured. The top ten quality indicators in the evaluation by its relevance, validity, reliability, impact, preference and application were decubitus ulcer, clean wound infection, fall, unplanned return to operation room, transfusion reactions, foreign body left In during procedure, unplanned readmission, wound infection after contaminated surgery, postoperative hemorrhage/hematoma, and cesarean section rate in order. The high priority quality indicators frequently measured could be used as primary national indicators. Standardized guidelines about monitoring indicators and the utilization will preliminarily be needed to compare and reuse the data for various purposes and improve the quality of care continuously.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1427-1439
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• 2008

The quality of track-bed fills of railways has been controlled by field measurements of density (${\gamma}_d$) and the results of plate-load tests. The control measures are compatible with the design procedures whose design parameter is $k_{30}$ for both ordinary-speed railways and high-speed railways. However, one of fatal flaws of the design procedures is that there are no simple laboratory measurement procedures for the design parameters ($k_{30}$ or, $E_{v2}$ and $E_{v2}/E_{v1}$) in design stage. A new quality control procedure, in parallel with the advent of the new design procedure, is being proposed. This procedure is based upon P-wave velocity involving consistently the evaluation of design parameters in design stage and the field measurements during construction. The key concept of the procedure is that the target value for field compaction control is the P-wave velocity determined at OMC using modified compaction test, and direct-arrival method is used for the field measurements during construction. The procedure was verified at a test site and the p-wave velocity turned out to be an excellent control measure. The specifications for the control also include field compaction water content of $OMC{\pm}2%$ as well as the p-wave velocity.

• Journal of the Korean Data and Information Science Society
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• v.19 no.2
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• pp.609-620
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• 2008

There may be several parallel equipments having the same function in a multi-stage manufacturing process, which affect the product quality differently and have significant differences in defect rate. The product quality may depend on what equipments it has been processed as well as what process variable values it has. Applying one model ignoring the presence of different equipments may distort the prediction of defect rate and the identification of important quality variables affecting the defect rate. We propose a procedure for data segmentation when constructing models for predicting the defect rate or for identifying major process variables influencing product quality. The proposed procedure is based on the principal component analysis and the analysis of variance, which demonstrates a better performance in predicting defect rate through a case study with a PDP manufacturing process.

• Journal of Korean Society for Quality Management
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• v.40 no.3
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• pp.306-315
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• 2012

Purpose: To ensure good quality munitions, we require quantitative risk management and optimal risk management of system characteristics. Methods: Failure mode and effects analysis (FMEA) is a widely used technique to assess or to improve reliability of products at early stage of design and development. Traditionally, the prioritization of failures for corrective actions is performed by developing a risk priority number (RPN). Results: This paper reestablishes an effective methodology for prioritization of failure modes in FMEA procedure. Revised evaluation criteria of RPN are devised. Conclusion: To verify the proposed methodology, it is applied to RPN evaluation for K21 infantry combat vehicle.

• IE interfaces
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• v.14 no.4
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• pp.409-420
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• 2001

In this paper, We study the development of Quality Competitiveness Assessment System(QCAS), which is a computer software developed to support the assessment criteria. It, first, describes the structure of the assessment criteria and the quality competitiveness model developed for promoting quality management. QCAS is then further explained by delineating its design, functional characteristics, and feedback from the experts. A systematic procedure is also proposed for possible application of QCAS in real world situations. Finally, This research propose a systematic procedure that can be used to apply QCAS in setting up a long-term plan for continuous quality improvement.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.21 no.47
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• pp.101-112
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• 1998

Recently, researchers show growing interest on product quality characteristic dependence and designing acceptance sampling plans under the quality dependence. This research intends to resolve a few theoretical and practical questions for better application of acceptance sampling when the quality characteristic of product items exhibits a statistical dependence and samples are inspected according to the production order. In this research, a mathematical programming model is developed for the economic modeling of sampling plans based on two evaluation criteria : the average outgoing quality(AOQ) and the average total inspection cost. An efficient solution procedure is then proposed using the functional structure of the two evaluation criteria and the procedure is numerically illustrated.

• Journal of Advanced Navigation Technology
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• v.13 no.6
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• pp.861-875
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• 2009

In order to make high quality software and high reliability software, systematic development management and organizational support are essential needed. Since 1990's Software process models such as ISO/IEC 15504 and CMMI have been used to improve organization capability. But these models have problems that are used to apply on large scaled organization or large project and so many practices are actually required. We present characteristics of ISO/IEC 15504, CMMI and K-model can easily apply to small and medium sized business or project, and propose the standard quality metric and accreditate procedure based on K-model for measuring quantitative quality level.