• Proceedings of the KWS Conference
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• 2002.10a
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• pp.330-335
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• 2002

Resistance spot welding is one of the most widely used processes in sheet metal fabrication. Quality assurance of welding has been important to increase the productivity. In this study, weld quality estimation using primary circuit dynamic resistance applied to the in-process real-time systems. For quality estimation, factors relating to quality were extracted from the dynamic resistance, measured in the timer. The relationship between these factors and weld quality was determined through a artificial neural network model. This method has the advantage over the conventional one, such as obtaining the quality information without the use of extra devices.

• Journal of the Ergonomics Society of Korea
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• v.29 no.2
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• pp.217-224
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• 2010

Research has been conducted to examine the effects of mechanical and sound characteristics of fabrics on affective quality. The present study developed the Affective Quality Evaluation and Estimation System for Textiles (AQEEST) with distinguished features that can be effectively used in the affective research of fabric frictional sound. The AQEEST consists of three subsystems (affective quality evaluation, affective quality estimation, and audible distance estimation subsystems) and each subsystem consists of three to four modules (e.g., evaluation condition setup, evaluation experimentation, and textile database management modules) depending on its functional requirements. The affective quality evaluation subsystem was designed to help administer an experiment in a systematic manner and present acoustic and visual stimuli simultaneously in various gait conditions (walking, jogging, and running) to mimic a more realistic situation of textile frictional sound production. Next, the affective quality estimation subsystem was designed to estimate the sound characteristics, affective qualities, overall psychological satisfaction, and reference cluster of a textile using its mechanical and/or sound characteristic information. Lastly, the audible distance estimation subsystem was designed to estimate the just noticeable sound pressure levels and audible distances of a textile for various gait conditions using its mechanical characteristic information. The AQEEST can be upgraded by accommodating more affective quality study results for various textiles.

• Journal of Digital Convergence
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• v.10 no.6
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• pp.197-203
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• 2012

In this paper, researching for the video quality estimation of IPTV in the situation that increase the broadcasting network traffic on the IPTV multicasting service using the ETSI TR 101 290 that is the European digital video quality standard estimating method and present the experiment result. Proving that the intimate relation is between IPTV video quality and ETSI TR 101 290 estimation, also ETSI TR 101 290 can detect the video quality factors which can't be detected by the exist video estimation methods.

• Journal of Korean Society for Quality Management
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• v.43 no.1
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• pp.57-66
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• 2015

Purpose: The purpose of this study is to apply the constrained Bayesian estimation methodology for product quality control process and prove the effectiveness of the product management by comparing with the well-known Bayes estimator through data performance result. Methods: The Bayes and constrained Bayes estimators were produced based on the theoretical background and for confirming the effectiveness of suggested application, the deviation index was defined and calculated for the comparison. Results: The statistical analysis result shows that applying the suggested estimation methodology, that is, constrained Bayes estimator improves the effectiveness of the index with regard to reduce the error by matching the first two empirical moments. Conclusion: Considering the advanced Bayesian approaches such as constrained Bayes estimation for the product quality control process, the newly defined deviation index reduces the error for estimating the parameter histogram which is reflected both location and deviation parameters and furthermore various Bayesian perspective approaches seems to be meaningful for managing the product quality control process.

• Journal of Korean Society for Quality Management
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• v.42 no.4
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• pp.747-756
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• 2014

Purpose: The purpose of this study is to apply the Bayesian estimation methodology for producing 'Korean Standard -Quality Excellence Index' model and prove the effectiveness of the new approach based on survey data by comparing the current index with the new index produced by Bayesian estimation method. Methods: The 'Korean Standard -Quality Excellence Index' was produced through the collected survey data by Bayesian estimation method and comparing the deviation with two results for confirming the effectiveness of suggested application. Results: The statistical analysis result shows that suggested estimator, that is, empirical Bayes estimator improves the effectiveness of the index with regard to reduce the error under specific loss function, which is suggested for checking the goodness of fit. Conclusion: Considering the Bayesian techniques such as empirical Bayes estimator for producing the quality excellence index reduces the error for estimating the parameter of interest and furthermore various Bayesian perspective approaches seems to be meaningful for producing the corresponding index.

• Journal of Korean Society for Quality Management
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• v.9 no.1
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• pp.51-60
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• 1981

This paper deals with the estimation of the Weibull parameters, which have a close relation with product reliability characteristics. Among the many kinds of estimation methods, Ishikawa's Weibull Probability Paper (WPP) is commonly used. The WPP is very convenient, but it has a great disadvantage in estimation accuracy by plotting method. It is very difficult to get the same results even if one use the same data several times. A computer program for the regression method is used for the parameter estimation to reduce these errors.

• Journal of Korean Society for Quality Management
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• v.15 no.2
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• pp.61-68
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• 1987

This paper considers the estimation of the parameters of a normal population from which a sample which has been censored at a known point is obtained. Simple estimators are presented which are given in closed forms. It is shown that maximum likelihood estimators are obtained by using the estimation procedure iteratively. Some computer simulation results are given.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.22 no.50
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• pp.363-372
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• 1999

This paper is to propose models for systematic classification and estimation of quality costs. Especially in this research, quality costs are categorized into three aspects, ie., conventional quality cost system, ZD(Zero Defect) quality cost system and Taguchi quality system. In conclusion, I hope that this study will have contribution to application of quality loss system for all the business in Korea.

• Proceedings of the KWS Conference
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• 2001.10a
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• pp.184-186
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• 2001

Quality estimation of the weld has been one of the important issues in RSW which is a main process of the sheet metal fabrication in auto-body industry. It was well known that among the various welding process variables, dynamic resistance has a close relation with nugget formation. In this study, a new quality estimation algorithm is developed with the primary dynamic resistance measured at welding machine timer. For this, Back propagation algorithm of neural network is used.

• Journal of Korean Society for Quality Management
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• v.19 no.2
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• pp.17-39
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• 1991

In many application of response surface methodology, good estimation of the derivatives of the response function may be as important or perhaps more important than estimation of mean response. Using a graphical method, we have studied the effect of outliers, missing observations, and design augmentation with respect to the slope estimation in the response surf ace designs.