• 한국통계학회:학술대회논문집
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• 한국통계학회 2005년도 춘계 학술발표회 논문집
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• pp.191-196
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• 2005

Knowing the time of the process change could lead to quicker identification of the responsible special cause and less process down time, and it could help to reduce the probability of incorrectly identifying the special cause. In this paper, we propose a MLE of the process change point when control charts with the fixed sampling rate (FSR) scheme or the variable sampling rate (VSR) scheme monitor a process to detect changes in the process mean and/or variance of a normal quality variable.

• 한국정보과학회논문지:소프트웨어및응용
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• 제32권12호
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• pp.1164-1177
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• 2005

현재 소프트웨어 개발 공정이 복잡해짐에 따라 개발하는 소프트웨어의 요구사항 역시 복잡해지고 있으며 요구사항 관리에 많은 노력이 소요되고 있다. 그러나 소프트웨어의 요구사항을 처음부터 모두 정의하는 것은 사실상 불가능하며, 개발이 진행되면서 환경은 변하기 마련이다. 또한 요구사항 변경은 개발보다 많은 비용이 소요되므로 체계적인 변경 관리를 통해 변경에 민첩하게 대응하고 관리되어야 한다. 본 논문에서는 소프트웨어 프로덕트 라인에서 요구사항 변경 관리 프로세스를 기반으로 체계적인 요구사항 변경 관리 방법을 제시한다. 소프트웨어 프로덕트 라인(software product lines)에서 어플리케이션의 요구사항은 도메인 요구사항과 밀접하게 관련되어 있으므로 어플리케이션 공학(application engineering) 단계에서 요구사항 변경이 발생했을 경우 도메인 공학(domain engineering) 단계를 이용하여 변경을 분석하고 관리하는 방법을 제시한다. 이러한 일관된 변경 관리를 통해 변경 범위를 분석하고, 변경 대처방안을 제시함으로써 변경 처리 결정을 내리는데 도움을 주며 한번 요청된 변경이 완벽하게 처리되도록 도와주어 같은 변경의 반복 요청을 막을 수 있기 때문에 잠재된 변경 비용을 절약할 수 있다.

• International Journal of Quality Innovation
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• 제5권1호
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• pp.1-9
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• 2004

The nonhomogeneous poisson process (NHPP) is often used to model repairable systems that are subject to a minimal repair strategy, with negligible repair times. In this situation, the system can be characterized by its intensity function. There have been many NHPP models according to intensity functions. However, the intensity function of system in use can be changed because of repair or its aging. We consider the single change point model as the modification of the power law process. The shape parameter of its intensity function is changed before and after the change point. We detect the presence of the change point using Bayesian methodology. Some numerical results are also presented.

• Journal of the Korean Data and Information Science Society
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• 제26권2호
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• pp.525-533
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• 2015

Modern production process is a very complex structure combined observations which are correlated with several factors. When the error signal occurs in the process, it is very difficult to know the root causes of an out-of-control signal because of insufficient information. However, if we know the time of the change, the system can be controlled more easily. To know it, we derive a maximum likelihood estimator (MLE) of the change point in a process when observations are from a multivariate IMA(1,1) process by monitoring residual vectors of the model. In this paper, numerical results show that the MLE of change point is effective in detecting changes in a process.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.616-621
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• 2009

Change orders represent one of the largest sources of cost growth on construction projects, but an efficient change management control system can help the projects steer clear of the constant construction changes. This study was performed to achieve a better understanding of all changes and to develop a new set of Best Practices using process mapping techniques. The project data for this research were collected from case studies of aviation projects implemented in Houston, Texas at Bush Intercontinental Airport. The findings and contributions of this research should help owners and project managers determine and identify major causes that impact project budget and schedule and implement solutions prior to them surfacing.

• 성인간호학회지
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• 제15권3호
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• pp.483-492
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• 2003

Purpose: The study was performed to identify the process of change, decisional balance and self-efficacy corresponding to the stage of smoking cessation behavior based on Transtheoretical Model in industrial workers. Method: A convenience sample of 146 industrial workers except for the never smokers, were recruited at a H industry in Ulsan. Data were collected from February 1 to 28, 2002. The research instruments were Stages of Change of Smoking Cessation Measure(DiClemente et al, 1991), Process of change(Prochaska, 1988), Smoking Abstinence Self Efficacy (SASE: DiClemente et al, 1985) and Decisional balance(SDB; Kim, 1999). Result: The results of this study were as follows; 1. The subjects were distributed in each stage of smoking cessation change: There were 64 subjects (43.0%) in the precontemplation stage, 35 subjects(23.5%) in the contemplation stage, 28 subjects(18.8%) in the preparation stage, 14 subjects(10.1%) in the action stage and 7 subjects(4.7%) in the maintenance stage. 2. Analysis of variance showed that experiental process(F=2.808, p=.042), behavioral process (F=4.567, p=.004) self-efficacy(F=9.809, p=.000), pros(F=11.107, p=.000), cons(F=6.686, p=.000), pros- cons(F=3.446, p=.018) were significantly associated with the stages of smoking cessation change. 3. Through discriminant analysis, it was found that 'PROS' was the most influential variable in discriminating the four stages of change. Conclusion: This study can provide the basis of staged matching smoking cessation program using TTM for more effective and useful intervention.

• Communications for Statistical Applications and Methods
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• 제15권3호
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• pp.421-427
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• 2008

This paper deals with the problem of testing for the existence of change in mean and estimating the change-point when the data are from the exponential distributions. The likelihood ratio test statistic and Gombay and Horvath (1990) test statistic are compared in a power study when there exists one change-point in the exponential means. Also the change-point estimator using the likelihood ratio and the change-point estimators based on Gombay and Horvath (1990) statistic are compared for their detecting capability via simulation.

• 한국기계가공학회지
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• 제19권6호
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• pp.49-54
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• 2020

The purpose of this study is to investigate the effects of the change in the spindle speed and the feed rate on the diameter change of a hole using a boring cutter for the internal boring process of AL6061-T4 alloys. The experimental results are quantitatively analyzed by applying the factor analysis and the response surface analysis of the experimental design method. The tendency of the diameter change according to the change in the spindle speed and feed level is also evaluated. During the internal boring process of AL6061-T4 alloys, the main factor affecting the diameter change is the spindle speed in which the diameter decreases as the number of revolutions increases. In addition, the diameter tends to increase as the feed is increased; however, as the number of spindle revolutions increases, the influence of the feed decreases.

• 한국과학교육학회지
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• 제24권1호
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• pp.1-16
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• 2004

The purpose of this study was to examine the role of cognitive conflict in the conceptual change process. Ninety-seven high school students in Korea participated in this study. Before instruction, we conducted pretests to measure learning motivation and learning strategies. During instruction, we tested the students' preconceptions about Newton's 3rd Law and presented demonstrations. After this, we tested the students' cognitive conflict levels and provided students learning sessions in which we explained the results of the demonstrations. After these learning sessions, we tested the students' state learning motivation and state learning strategy. Posttests and delayed posttests were conducted with individual interviews. The result shows that cognitive conflict has direct/indirect effects on the conceptual change process. However, the effects of cognitive conflict are mediated by other variables in class, such as state learning motivation and state learning strategy. In addition, we found that there was an optimal level of cognitive conflict in the conceptual change process. We discuss the complex role of cognitive conflict in conceptual change, and the educational implications of these findings.

• 건축역사연구
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• 제28권2호
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• pp.31-40
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• 2019

Considering the situation in the early 20th century when the existing urban system centered on urban areas began to change, the biggest factors causing urban structural changes in urban areas are construction of railroad and urban dismantling. The change process of Eupseong, in the microscopic viewpoint, can be understood as a process of change in the course of dismantlement of town's demarcation, improvement of accessibility and urban expansion due to the construction of railroads, process of urban expansion following the crumbling boundaries and structural changes. This study aimed to look at the transformation process of the Eupseong in the early 20th century, focusing on the demolition of the castle and the railway construction from a microscopic point of view of city.