• The Journal of Korean Society for Radiation Therapy
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• v.23 no.2
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• pp.97-102
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• 2011

Purpose: IMRT QA using 2Dimensional array detector is carried out with condition for discrete dose distribution clinically. And it can affect uncertainty of evaluation using gamma method. We analyze gamma index variation according to grid size and suggest validate range of grid size for IMRT QA in Hospital. Materials and Methods: We performed QA using OniPro I'mRT system software version 1.7b on 10 patients (head and neck) for IMRT. The reference dose plane (grid size, 0.1 cm; location, [0, 0, 0]) from RTP was compared with the dose plane that has different grid size (0.1 cm, 0.5 cm, 1.0 cm, 2.0 cm, 4.0 cm) and different location (along Y-axis 0 cm, 0.2 cm, 0.5 cm, 1.0 cm). The gamma index variation was evaluated by observing the level of changes in Gamma pass rate, Average signal, Standard deviation for each case. Results: The average signal for each grid size showed difference levels of 0%, -0.19%, -0.04%, -0.46%, -8.32% and the standard deviation for each grid size showed difference levels of 0%, -0.30%, 1.24%, -0.70%, -7.99%. The gamma pass rate for each grid size showed difference levels of 0%, 0.27%, -1.43%, 5.32%, 5.60%. The gamma evaluation results according to distance in grid size range of 0.1 cm to 1.0 cm showed good agreement with reference condition (grid size 0.1 cm) within 1.5% and over 5% in case of the grid size was greater than 2.0 cm. Conclusion: We recognize that the grid size of gamma evaluation can make errors of IMRT QA. So we have to consider uncertainty of gamma evaluation according to the grid size and apply smaller than 2 cm grid size to reduce error and increase accuracy clinically.

• Communications for Statistical Applications and Methods
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• v.4 no.3
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• pp.617-628
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• 1997

시계열 자료의 변이상태(transition status)에 대한 판별은 여러 분야에서 연구되고 있다. 하지만 변압기의 진동신호와 같이 특정한 시계열모형을 적합시키기 힘든 자료는 변이 상태에 대한 판별이 쉽지 않다. 본 논문에서는 정상적인 변압기에서 발생하는 진동신호에 대하여 각 주기별 최대값, 자기상관계수 및 편자기상관계수 등의 경험적 표본분포를 연구한 후, 이를 이용한 관리도를 만들어 변압기 진동신호의 변이상태에 대한 판별을 하였다. 이 방법은 품질관리의 관리도 이론을 시계열자료에 응용한 것으로 비정상적인 변압기 진동신호의 판별에 만족스러운 결과를 가져왔다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.33 no.4
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• pp.245-258
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• 2015

This study aimed to conduct the standardization of various specifications for determining the proper construction and operation of domestic CORS (Continuously Operating Reference Station). To achieve the plan, the standardization was proposed for various compositions of CORS, such as the data quality, structure, and equipment. Also, we have studied the method for empirically determining the reference values of QC (Quality Check) of CORS data. Those large amounts of samples for each QC index values were built to approach in empirical and statistical methods. In fact, those general and recommended reference values were determined from analyzing the sample distributions, using the empirical and statistical approaches. The result is expected to be utilized for a variety of research fields for standardization, accurate data acquisitions and service operations for the domestic CORS

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.311-315
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• 2002

Six sigma management has obtained good results in manufacturing and service industry as a new innovation approach to improve the enterprise-wise quality processes. However, there are lacks of implementation cases in the construction industry and furthermore, a results from a few cases applied is not successful enough to draw an attraction against the six sigma method. The main goal of this paper is to provide a comparative study regarding the pre-requisite conditions for the application of six sigma to the construction industry. Then, it present a generic procedure model that can support the introduction of six sigma management. Finally, the model is verified through the case study and lessons learned form a case are presented.

• 한국IT서비스학회:학술대회논문집
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• 2002.06a
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• pp.219-225
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• 2002

소프트웨어 개발 프로젝트에 대한 위험관리(risk management) 이론을 근거로, 소프트웨어 품질, 요구사항 불확실성, 통제표준화, 상호작용에 대한 5개의 가설이 설정되었고, 3개의 SI 회사로부터 117개 표본이 추출되어서 구조방정식모형에 의해서 실증적으로 검증되었다. 본 연구결과에 따르면 요구사항 불확실성과 통제 표준화는 소프트웨어 품질에 직접적인 영향을 미치지 않고, 사용자-프로젝트 팀 간의 상호작용에 직접적인 영향을 미치며, 이를 통해서 소프트웨어 품질에 간접적인 영향을 미친다. 그럼으로, 요구사항 불확실성이 낮을수록, 그리고 통제 표준화가 높을수록, 사용자-프로젝트 팀 간의 상호작용은 높아져서 궁극적으로는 소프트웨어 품질이 높아진다고 해석할 수 있다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.17 no.1
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• pp.79-86
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• 1999

In this study, we investigated methods of quality check for digital basemaps and proposed effective methods of quality check. We used new statistical methods for quality control in order to carry out quality check for digital basemaps. We proposed 2-stage complete sampling and 2-stage cluster sampling method to improve present statistical methods of quality check(1-stage complete sampling method). We estimated error rate and number of omitted objects using simulated data about all delivered digital basemaps and estimated variances about it. We could determine confidence interval about error rate and number of omitted objects.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2005.05a
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• pp.173-177
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• 2005

본 연구는 닭고기의 품질 등급을 설정하기 위한 기초 자료로 이용하기 위하여 시중 도계 장을 대, 중, 소로 구분하여 생산 관리 책임자들을 대상으로 닭고기 등급제 적용에 따른 도계 장 및 유통업소 및 판매장 조사를 통하여 등급판정 방법, 표본 수 선발 방법 등을 설정하여 설문지에 의한 방문 조사를 실시한 결과는 다음과 같았다. 도계 장 설문조사에서 등급제 적용 시 적용 단위는 대부분의 도계 장에서 농가단위보다는 롯트 단위를 선호하였다. 닭고기 등급제 조사방법은 대부분의 도계 장에서 전수조사보다는 샘플조사를 선호하였다. 닭고기 등급제 시행초기에는 도계 장에서 요청한 물량에 대해서만 등급판정을 실시하는 것을 선호하였다. 통닭 뿐 만 아니라 부분 육에 대해서도 등급제를 적용해야 된다는 의견이 많았다. 닭고기 등급제 적용시의 중량의 범위는 대규모 도계 장에서는 $8^{\sim}12$호에 대해서 등급 판정을 선호하였다.

• Journal of Information Management
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• v.41 no.3
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• pp.45-66
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• 2010

The purpose of this study is to develop service quality measurement model(DL-SQI model) which are able to measure objectively service quality of digital libraries in Korea and to measure user perceived service quality performance with DL-SQI model. This study also investigates the influence of service quality on customer satisfaction and customer loyalty. Before measurement, two principal rules and indicator formula were made to measure the service quality. Finally service quality of three digital libraries selected as samples was measured and analyzed in various points of view. It was developed a DL-SQI Consequences Model and testified it through path analysis using structural equation model.

• Culinary science and hospitality research
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• v.19 no.4
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• pp.211-230
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• 2013

The purpose of this study was to investigate importance and performance about the quality attributes of bean coffee and instant coffee for the Koreans and the Mongolians. The survey was conducted in Seoul and Gyeonggi Province, Korea and in Ulaanbaatar, Mongolia from April to May, 2012. The questionnaire was distributed to 380 Koreans and 380 Mongolians, and 253 and 250 copies were collected from the Koreans and the Mongolians, respectively, for statistical analyses. For the importance-performance analysis(IPA), 14 quality attributes of bean coffee and instant coffee were investigated. The main results of this study were as follows. In the importance and performance comparison about the bean coffee quality, taste, aroma, quantity, price, hygiene, freshness and shelf life were more important to the Koreans than to the Mongolians. On the other hand, nutrition and ingredient were regarded as more important attributes for the Mongolians. Also, price, nutrition, temperature and ingredient were better performance to the Mongolians than to the Koreans. In the importance and performance comparison about the instant coffee quality, quantity and price were more important to the Koreans than to the Mongolians. However, nutrition and temperature were more important to the Mongolians. Moreover, nutrition, temperature, variety and freshness were better performance to the Mongolians than to the Koreans. According to the IPA results of 14 quality attributes of bean coffee, the selection attributes with high importance but low performance were price and shelf life for the Koreans, while nutrition, hygiene and ingredient for the Mongolians. For instant coffee, the selection attributes with high importance but low performance were hygiene and concentration for the Koreans, while concentration and ingredient for the Mongolians.

• Journal of Korean Society for Quality Management
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• v.28 no.3
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• pp.18-30
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• 2000

Recent studies have shown that the $\bar{X}$ chart with variable sampling intervals(VSI) and the $\bar{X}$ chart with variable sample size(VSS) are much quicker than Shewhart $\bar{X}$ chart in detecting shiks in the process. Shewhart $\bar{X}$ chart has been beneficial to detect large shifts but it is hard to apply Shewhart $\bar{X}$ chart in detecting moderate shifts in the process mean. In this article the $\bar{X}$ chart using variable sample size(VSS) and variable sampling Intervals(VSI) has been proposed to supplement the weak point mentioned above. So the purpose of this paper is to consider finding the design parameters which minimize expected loss costs for unit process time and measure the performance of VSSI(variable sample size and sampling interval) $\bar{X}$ chart. It is important that assignable causes be detected to maintain the process controlled. This paper has been studied under the assumption that one cycle is from starting of the process to eliminating the assignable causes in the process. The other purpose of this article is to represent the expected loss costs in one cycle with three process parameters(sample size, sampling interval and control limits) function and find the three parameters.