• Journal of the Korean Data and Information Science Society
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• v.18 no.4
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• pp.963-972
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• 2007

When a control chart signals that a special cause is present, process engineers must initiate a search for and an identification of the special cause. Knowing the time of the process change could lead to identify the special cause more quickly, and to take the appropriate actions immediately to improve quality. In this paper, we propose the maximum likelihood estimator (MLE) for the process change point when a control chart is used in monitoring the parameters of a process in which the observations can be modeled as a first-order autoregressive(AR(1)) process plus an additional random error.

• Journal of the Korean Society of Earth Science Education
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• v.10 no.3
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• pp.254-261
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• 2017

This study is to investigate preconception of elementary school students and Belizean elementary school teachers and to devise experiment to understand a cause of seasonal change. An open-ended questionnaire and interviews were conducted for 91 6th grade students who didn't learn seasonal change and 10 Belizean teachers to find out preconception of seasonal change and they were categorized by using inductive analysis. They thought that the Earth's rotation, the distance between the Sun and the Earth, the Earth's revolution, pollution and climate change cause seasonal change. And it found out that these misconceptions come from difficulty in awareness of space and impreciseness of textbooks and books and so on. The experiment was designed to correct inaccurate preconception and to improve lessons of seasonal change. It is to measure a meridian altitude and a length of daytime and nighttime and to compare them. This experiment can help to understand the cause of seasonal change by measuring natural phenomenons like the meridian altitude and the change of length of daytime by model.

• Communications for Statistical Applications and Methods
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• v.14 no.1
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• pp.155-167
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• 2007

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 the maximum likelihood estimator (MLE) for the process change point when a control chart is used in monitoring the mean of a process in which the observations can be modeled as an AR(1) process plus an additional random error. The performance of the proposed MLE is compared to the performance of the built-in estimator when they are used in EWMA charts based on the residuals. The results show that the proposed MLE provides good performance in terms of both accuracy and precision of the estimator.

• Korean Journal of Environmental Biology
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• v.35 no.1
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• pp.37-46
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• 2017

Climate change is the biggest concern of the $21^{st}$ century. Greenhouse gas (GHG) emissions from various sectors are attracting attention as a cause of climate change. The DeNitrification-DeComposition (DNDC) model simulates GHG emissions from cropland. To study future GHG emissions using this simulation model, various factors that could change in future need to be considered. Because most problems are from the agricultural sector, DNDC would be unable to solve the factor-changing problem itself. Hence, it is necessary to link DNDC with separate models that simulate each element. Climate change is predicted to cause a variety of environmental disasters in the future, having a significant impact on the agricultural environment. In the process of human adaptation to environmental change, the distribution and management methods of farmland will also change greatly. In this study, we introduce some drawbacks of DNDC in considering future changes, and present other existing models that can rectify the same. We further propose some combinations with models and development sub-models.

• Journal of Science Education
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• v.35 no.2
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• pp.274-282
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• 2011

The purpose of this study was to investigate elementary and middle school (grade 5 and 7) students' perceptions of global warming and climate change. A total of 239 students completed opened-form questionnaire consisting of cartoons regarding global warming and climate change. The results showed that are as follows. Elementary and middle school students had low level of perception of global warming and climate change. A majority of students rightly believed that the global warming is related to greenhouse gases, glacier, environmental pollution, etc. Also, Many students had scientific concepts about the cause of global warming while some of the students had misconceptions that destruction of the ozone layer will cause an global warming. We have found that some of the students of elementary and middle school had confused between the cause of global warming and ozone depletions.

• Structural Engineering and Mechanics
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• v.59 no.6
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• pp.1095-1120
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• 2016

This paper investigates the change of structural characteristics of steel cable-stayed bridges after cable failure. Cables, considered as the intermediate supports of cable-stayed bridges, can break or fail for several reasons, such as fire, direct vehicle clash accident, extreme weather conditions, and fatigue of cable or anchorage. Also, the replacement of cables can cause temporary disconnection. Because of the structural characteristics with various geometric nonlinearities of cable-stayed bridges, cable failure may cause significant change to the structural state and ultimate behavior. Until now, the characteristics of structural behavior after cable failure have rarely been studied. In this study, rational cable failure analysis is suggested to trace the new equilibrium with structural configuration after the cable failure. Also, the sequence of ultimate analysis for the structure that suffers cable failure is suggested, to study the change of ultimate behavior and load carrying capacity under specific live load conditions. Using these analysis methods, the statical behavior after individual cable failure is studied based on the change of structural configuration, and distribution of internal forces. Also, the change of the ultimate behavior and load carrying capacity under specific live load conditions is investigated, using the proposed analysis method. According to the study, significant change of the statical behavior and ultimate capacity occurs although just one cable fails.

• Journal of Preventive Medicine and Public Health
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• v.46 no.2
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• pp.105-110
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• 2013

Objectives: The mass media play a crucial role in risk communication regarding climate change. The aim of this study was to investigate the trend in journalistic reports on climate change in the daily newspapers of Korea. Methods: We selected 9 daily newspapers in Korea, which according to the ABC Association, represented 77% of newspaper circulation, out of a total of 44 Korean daily newspapers. The collected articles were from 2009 to 2011. All of the articles were sorted into the following 8 categories: greenhouse gas, climate change conventions, sea level rise, Intergovernmental Panel on Climate Change synthesis reports, expected damage and effect, use of fossil fuels, global warming, and mitigation or adaptation. A chi-squared test was done on the articles, which were counted and classified into cause, effect, and measurement of climate change according to the newspaper's majority or minority ownership structure. Results: From the 9 selected newspapers, the number of articles on climate change by month was greatest in December 2009. Generally, the articles vague about climate change (lack of precise data, negative or skeptical tone, and improper use of terminology) were much more common than the articles presenting accurate knowledge. A statistical difference was found based on ownership structure: the majority-owned newspapers addressed the cause of climate change, while the minority-owned newspapers referred more to climate change measurement. Conclusions: Our investigation revealed that generally Korean daily newspapers did not deliver accurate information about climate change. The coverage of the newspapers showed significant differences according to the ownership structure.

• Safety and Health at Work
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• v.12 no.4
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• pp.505-510
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• 2021

Background: Factors related to root causes can cause commonly occurring accidents such as falls, slips, and jammed injuries. An important means of reducing the frequency of occupational accidents in small- to medium-sized enterprises (SMSEs) of South Korea is to perform intensity analysis of the root cause factors for accident prevention in the cause and effect model like decision models, epidemiological models, system models, human factors models, LCU (life change unit) models, and the domino theory. Especially intensity analysis in a robot system and smart technology as Industry 4.0 is very important in order to minimize the occupational accidents and fatal accident because of the complexity of accident factors. Methods: We have developed the modern cause and effect model that includes factors of root cause through statistical testing to minimize commonly occurring accidents and fatal accidents in SMSEs of South Korea and systematically proposed educational policies for accident prevention. Results: As a result, the consciousness factors among factors of root cause such as unconsciousness, disregard, ignorance, recklessness, and misjudgment had strong relationships with occupational accidents in South Korean SMSEs. Conclusion: We conclude that the educational policies necessary for minimizing these consciousness factors include continuous training procedures followed by periodic hands-on experience, along with perceptual and cognitive education related to occupational health and safety.

• Journal of the Korean Home Economics Association
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• v.26 no.4
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• pp.129-160
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• 1988

The purpose of the present study is to understand the change in the relation between mother-in-law and daughter-in-law according to the social change in comparison with the survey effects in 1974 (ko Jung-Ja) and 1985 to find out the cause of conflict in both side of power structure and affection structure, indicating behavior, the influences on the relationships among family, possible meditators. this thesis was made by an experimental research. Data were collected from 146 mothers-in-law and 141 daughters-in-law in Pusan. The collected data were analysed by statistical methods such is as follows, 1. cause of conflict In power structure the cause of conflict is, in the case of mother-in-law opinion opposion and shaughty attitude by daughter in-low and, in the case of daughter-in-law, domestic dominance. It is thought that there is a difference of viw\ew between mother-in-law and daughter-in-law about the possesion of economic dominance and many conflicts rises because of economic dominance. but the study in 1985 than 1974 suggests the possibility of conflict meditator because mother-in-law and daughter-in-law do homework dependently in the practice of power. In affection structure, the chief dissatisfaction toward daughter-in-law showes the change in time. In 1974, there was no affection and respect. In 1985, the rate of doing without consultation was high. Also, the lack of communication of mother-in-law and daughter-in-law is the cause of conflict. 2. Indicating behavior the rate of thinking alone if high in both sides. But in the survey of 1985, the covert verbal aggressive action with which mother-in-law appeals to her daughter and daughter-in-law to husband is rising. 3. Influence on the relationship among family by the conflict between mother-in-law and daughter-in-law. the conflict between mother-in-law and daughter-in-law play negative effects on the intimacy and relation between husband and wife. 4. Conflict mediation behavior As compremiser, it is suggested that in the case of daughter-in-law the position and role of husband is important and, in the case of mother-in-law respects mother-in-law, daughter-in-law and gives her the role.

• Journal of Society of Preventive Korean Medicine
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• v.7 no.1
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• pp.139-150
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• 2003

This study tried to know the chang of lifestyle and the factors causing of lifestyle change by the outcome of oriental medical examination for labors in one of the automobile factories in Jeon Buk area. The results will be helpful to the effective health care for the labors in factory. Oriental medical examination was done 22 times from May 20 to June 19, 2002. The numbers of labor who received oriental medical examination were 531, and 300 questionnaires among them were collected. The results were as follows: 1) General characteristics of examinee for oriental medical examination; total 300 labors, high percentage in age range $31{\sim}45$ years old, mostly married, high percentage of high school in completion of study. High percentages in drinking, smoking, and working hour were less than 1 time per week, non-smoking, and above 10 hours, respectively. High percentages in working year and salary were $11{\sim}15$ years. 2) The degree of lifestyle change by the oriental medical examination had the highest score with consult of oriental medicine doctor, and the lowest score was from moire typography result. 3) The degree of lifestyle change by medical examination was highly influenced by the subject characteristics that were less than 1 time per week for drinking, non-smoking, and less than 10 years of working year. 4) For the lifestyle change by the cognition of subject, the subjects who had high confidence for oriental medical examination, high recognition for oriental medical examination's requirement, high concern for health. effective cognition for early detection of disease, had high degree of lifestyle change. 5) The variables that cause lifestyle change in Sasang constitutional analysis result were early detection of disease, type of smoking, working year, moire typography result, interview for health. The variables that cause lifestyle change in moire typography result were type of drinking, ages, working year, consult for health, moire typography result. The variables that cause lifestyle change in interview with oriental medicine doctor were constitutional analysis and moire typography result.