• Proceedings of the Korean Statistical Society Conference
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• 2005.05a
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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.

• Journal of KIISE:Software and Applications
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• v.32 no.12
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• pp.1164-1177
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• 2005

As the software development process becomes complicated, software requirements become complicated, too. Many efforts are needed in requirements management. It is impossible to define all requirements of software at first, and the development environment changes as project is gone. As the cost of requirements change management is much more than development cost, the changes should be controled immediately through systematic change management. In this paper, I suggest a method to manage requirements change systematically based on the change management process in software product lines. The requirements change at the application engineering process is analyzed and managed using the domain engineering process because the application requirements are customized from the domain requirements in software product lines. Such the consistent change management helps to make decisions about changes by change impact analysis and alternative solution design. Through this method, the potential change costs can be saved because same change requests are not repeated by controlling the change requests completely.

• International Journal of Quality Innovation
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• v.5 no.1
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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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• v.26 no.2
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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.

• International conference on construction engineering and project management
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• 2009.05a
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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.

• Korean Journal of Adult Nursing
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• v.15 no.3
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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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• v.15 no.3
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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.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.6
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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.

• Journal of The Korean Association For Science Education
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• v.24 no.1
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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.

• Journal of architectural history
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• v.28 no.2
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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.