• Korean Journal of Clinical Laboratory Science
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• v.52 no.2
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• pp.91-97
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• 2020

Standardization of vitamin analysis continues around the world, and much effort has been made to improve the accuracy of the results. This study analyzed the sigma metrics of the vitamin D test using the external quality assessment (EQA) program. Sigma metrics is used for quantitative tests performed in the laboratory, and the test results can be objectively visualized in terms of quality. This analysis was performed based on the accuracy of the College of American Pathologists (CAP) using the results of the 2019 accuracy-based vitamin D (ABVD) survey, and about 300 laboratories participated in the survey. Reference values were obtained by the Center for Disease Control and Prevention (CDC) reference laboratory. At six different concentrations, the sigma metrics were analyzed to be 1.00, 1.85, 2.42, 1.01, 1.54 and 0.78, respectively. An average of 1.43 sigma metrics was determined. In particular, only positive biases for ABVD-16 and 17 were shown in the liquid chromatography tandem-mass spectrometry (LC-MS/MS), which is the standard method for vitamin D determination when compared to the reference values. The causes of the difference can be explained by cross reactivity to various vitamin D metabolites. Laboratories need to improve their overall performance.

• Communications for Statistical Applications and Methods
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• v.15 no.3
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• pp.451-464
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• 2008

Six sigma is the rating that signifies "best in clas", with only 3.4 defects per million units or operations. Higher sigma quality level is generally perceived by customers as improved performance by assigning a correspondingly higher satisfaction score. The process capability indices and the sigma level $Z_{st}$ have been widely used in six sigma industries to assess process performance. Most evaluations on process capability indices focus on point estimates, which may result in unreliable assessments of process performance. In this paper, we consider statistical inference for process capability indices $C_p$, $C_{pk}$ and $C_{pm}$. Also, we study better testing procedure on assessing sigma level $Z_{st}$ and capability index $C_{pm}$, for practitioners to use in determining whether a given process is capable. The proposed method is easy to use and the decision making is more reliable. Whether a process is clearly normal or nonnormal, our bootstrap testing procedure could be applied effectively without the complexity of calculation. A numerical result based on our proposed method is illustrated.

• The Korean Journal of Applied Statistics
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• v.23 no.6
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• pp.1035-1045
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• 2010

Products and/or services should be objectively verified in terms of the technological and use-conditional considerations before entering a market. Every organization or company tries to find the better procedure and method for checking the core needs of customers based on their experience in the market and looks for continuous ways to evaluate the power of products and services(PoP). They also prefer the overall evaluation of indices that could reflect various customer needs, rather than a separate evaluation index for each characteristic of the product or service. S. Ko (2008) proposes a Multi-characteristics Sigma Level(MSL) that can simultaneously evaluate many characteristics of a product or service. In this research, using MSL and a new Blue Ocean Index(BOI), an application of NPS, mobile phone field test is considered from a practical and statistical point of view.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.1333-1334
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• 2010

• Proceedings of the Korean Information Science Society Conference
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• 2007.06a
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• pp.51-52
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• 2007

• The Magazine for Energy Service Companies
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• s.37
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• pp.32-35
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• 2005

나용환(羅龍煥) 정보화시스템실장은 공단 내 SixSigma T/F팀장을 겸하고 있다. 지난 81년 입사하여 올해로 25년째를 맞고 있는 나실장은 공단 홈페이지 내 정보교류센터(IEC)를 운영하면서 쌍방향 정보교류를 구상한 끝에 공공기관으로서는 획기적인 것으로 평가되는 '캐쉬마일리지'제도를 시행하고 있다. 사이트 내에 ESCO투자제안방이 따로 있을 정도로 ESCO들에게 거는 기대가 크다고 말하는 나 실장에게 물었다.

• Proceedings of the Safety Management and Science Conference
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• 2005.05a
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• pp.129-135
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• 2005

This paper proposes the interated and balanced project management system for software and IT by considering BSC, MBNQA, ISO 9001, Six Sigma, CMM and SPICE. This system can be extended to assess the various project management practices.

• Journal of the Korean Professional Engineers Association
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• v.33 no.1
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• pp.83-88
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• 2000

Taguchi developed and provided various independent methods for actual application in design of experiments. Taguchi method is described in philosophy, method and others related to quality management. This thesis is one of case studies for improving the bond strength of epoxy resin by Taguchi method which is applied as a optimum developing tool in six sigma management revolution in many companies.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1664-1667
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• 2005

The main function of Ball-Stop part is to operate power shift for vehicle with more than 5 ton when a driver changes gear using suitable force. This paper presents the implementation of a DFSS(Design For Six Sigma) for robust design of Ball-Stop part of power shift. The factors influencing Ball-Stop part performance is derived to find control factor. Based on this factor, contact force between head and detent pin analysis is performed to get optimal factor is analyzed and compared with contact force test result to verify reliability of design. This makes clear the reason why the proposed one is necessary and the role of DFSS.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.4
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• pp.8-14
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• 2006

The important function of Ball-Stop part is to operate power shift using suitable pneumatic force for vehicle with more than 5 ton when a driver changes gear. In this paper, we have applied the concept of the DFSS(Design for Six Sigma) to robust design of Ball-Stop part. First, we have found the control factors which could mainly influence the performance of the Ball-Stop part. The simulations of contact between head and detent pin was performed to evaluate effect of control factors according to DOE(Design of experiment) by using $ADAMS^{(R)}$. Finally, we have obtained optimal levels of each factors using $MINITAB^{(R)}$. Through the comparison of the result of optimized design with one of inintial design, we have verified the usefulness of DFSS method which can be applied to robust design of mechanical systems.