• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.731-736
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• 2001

In this thesis, the study on controlling of cracks of concrete box culvert in early ages is presented. The optimum construction method and economical analysis were proposed also through the experiment of the material and field test. As a result of the experiment of the material, using fly ash, CSA expansive agent and BELITE cement(type IV) showed good result in the control of cracks induced by heat of hydration and shrinkage. As a result of construction test analysis, the maintenance time of form system did not show a big difference in controlling of cracks. Control of distribution of reinforcement, spacing of expansion joint and use of BELITE cement showed big differences in the control of cracks in early ages. As a result of economical analysis, control of construction variables before construction can make it possible to reduce the repair expense.

• Journal of The Korean Association For Science Education
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• v.19 no.4
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• pp.674-683
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• 1999

The purpose of this study was to compare the ideas of pupils with that of the scientists about controlling and identifying of variables, in the two cases: open or guided inquiry. The subjects were the 7th grade boys and girls in a school, in Seoul, Korea. For the guided inquiry, the problems were given by the experiments of pupils' text. Pupils were asked to identify the variables in the experiments. For the open inquiry, pupils set their own inquiry problem. The pupils whose marks are within upper one-third of three classes were chosen. Pupils' ideas on variables were investigated in the design of experiment for their problems. In that, questionnaire developed by researchers was used. In the former, many of the pupils identify just only one variable despite of the fact there were two independent or dependent variables in the experiments. In the latter, the number of independent variables increased two or three. However, pupils do not control independent variables: they vary two independent variables simultaneously in the design of experiment. From these, we compared the pupils' ideas on variables with the scientists'

• Journal of the Korean Data and Information Science Society
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• v.20 no.1
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• pp.191-202
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• 2009

In this study, we drive the one dimensional marginal transform function, probability density function and probability distribution function for the random variables $T_{{\xi}N}$ (Time taken by the servers during the vacations), ${\xi}_N$(Number of vacations taken by the servers) and ${\eta}_N$(Number of customers or units arrive in the system) by controlling the variability of two random variables simultaneously.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1993.06a
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• pp.1262-1265
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• 1993

The paper discusses the problem of controlling systems with a very high number of input variables effectively by fuzzy If . . . then rules. The basic idea is the partition of the state space into domains, which step can be done even iteratively several times, and every domain has its own sub rule base referring to a considerably lower number of variables than the original space. In this manner the number of necessary rules is drastically reduced and time complexity of the control algorithm remains acceptable.

• The Korean Journal of Community Living Science
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• v.18 no.1
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• pp.63-70
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• 2007

The purpose of this study is to find out how family, school and community variables influence internet behavior problems in adolescents. By focusing on sex differences, this study analyzes female as well as male behavior problems. The data used in this study are gathered from 1,046 middle and high school students in a national sampling. The results are as follows. Internet addiction is the most frequently occurring problem. A chi-square test shows that male students have higher experience rates than female students in obscene chatting and violent games. A series of logistic regressions are performed to blow the relative influence of independent variables controlling for each other. In the case of male students' internet behavior problems, region, communications with their parents, interactions with their close friends, and satisfaction with community facilities are significant variables. Interactions with friends are significant in predicting behavior problems of both female and male students. Suggestions and implications with regard to intervention strategies for adolescents are discussed.

• Journal of Korean Elementary Science Education
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• v.28 no.2
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• pp.154-160
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• 2009

Correlational reasoning is used to analyze results from an experiment and create meaningful relationships among variables. Although there were many recognition development studies, not a single study found the optimal period for the development of logical thinking. Therefore, the purpose of this study is to find the optimal period for students whose logic for variable controlling and correlational reasoning are poor. This study made a logic program treatment subject for students between the 4th and 8th grade whose recognition in reasoning has not been developed in general in order to find the optimal period for their development. The variable-controlling reasoning was performed the program of voice survey and sugared-water melting in subsection survey and sugared-water melting in subsection. And, the correlation reasoning was performed the program of rat's size and tail color, treatment, and effect. As a result of research, students, who were not formed variable controlling and correlational reasoning, could be known to be enhanced through learning, but to fail to be formed the qualitative change like the cognitive development. In other words, the optimal period couldn't be found that is grown the formation of students, who are not formed the variable controlling and correlational reasoning, through learning. It is expected that this research can contribute to the improvement of students' cognitive level and there would be more active researches in different fields to improve the cognitive level.

• Korean Journal of Health Education and Promotion
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• v.32 no.5
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• pp.73-81
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• 2015

Objectives: We tried to confirm physical activity of 1,000 Kcal per week was a meaningful point in controlling coronary artery disease risks in female older adults. Methods: Participants were 66 female older adults recruited from senior welfare center. Participants were provided with accelerometer (e-step, Kenz, Japan) for measuring daily energy expenditure. Graded exercise test was done for measuring aerobic fitness. Blood glucose and lipid were analyzed. Framingham risk score was calculated based on blood glucose, blood lipid, and smoking. These variables were compared between the group expended more than 1,000 Kcal/week and the group with energy expenditure below 1,000 Kcal/week. Results: The group expended over 1,000kcal/week showed to be superior to the counterpart group in following variables; AC(Abdominal Circumference), %BF, $HR_{rest}$(resting heart rate), $VO_{2peak}$, FBG, LDL-C, TG, BDI-II, QOL, AR(Absolute Risk), RR(Relative Risk). Conclusions: The group expended over 1,000 Kcal/week was likely to have less probability in CAD than group expended less than 1,000 Kcal/week. The result of this study suggests the important role of active daily life that can be replaced with that of regular exercise especially for those who are not available to do structured exercise.

• Journal of the Korean Data Analysis Society
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• v.20 no.6
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• pp.2759-2769
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• 2018

The behavioral finance view on the existence of asset pricing anomalies is based on two factors: investors' sentiment and limits to arbitrage. This paper tries to examine the effect of investors' sentiment on the stock price in the Korean stock market. In order to measure investors' sentiment, we constructed the sentiment index using principal component of five sentiment variables. By using sentiment index as an additional independent variable to three risk factors, impacts of the sentiment index on individual stocks and 25 portfolios sorted by BM-size are examined. Main results found are as follows: 1) not only all three risk factors show positive impacts on the return of individual stock, but also the sentiment index has a positive impact. SI alone explains 15% of individual return variation. 2) among four independent variables, the most important factor turned out to be the market risk factor and investors' sentiment has better explanatory power on stock price than the size effect. 3) after controlling the market risk factor, the coefficient of the sentiment index for the smallest size and highest book/market value portfolios is significantly positive. 4) all the coefficients of the sentiment index for 25 portfolios sorted by BM-size have significant positive value after controlling size or (and) value.

• The Journal of Industrial Distribution & Business
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• v.12 no.7
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• pp.27-39
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• 2021

Purpose: The researchers reviewed the previous studies on the psychological anxiety and economic damage during the recent COVID-19 pandemic to understand the satisfaction, awareness and attitude of the residents in Jeju, Korea. Research design, data and methodology: 215 samples based on self-reported survey were collected for path analysis focused on controlling variables in demographic characteristics in PLS-SEM using Smart PLS 3.0. Results: The researchers found the Satisfaction with COVID-19 Prevention Measures and the Awareness of Tourism Crisis affect Attitude toward Tourism of the residents with the explanatory power (R² = 0.209). Age was found to be the only significant controlling variable in this model for the Awareness of Tourism Crisis to Attitude toward Tourism. Conclusions: The attitude toward tourism is influenced by the level of satisfaction of the prevention service for COVID-19 as well as the awareness of the crisis. Residents have different level of the tourism crisis awareness by the status of their economic activities while there is no differences in all age groups for satisfaction in the quarantine service. The study suggests that the importance of the public health service should be preferentially concerned for residents to have stable economic activities where the tourism is the major industry.

• Industrial Engineering and Management Systems
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• v.12 no.4
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• pp.406-415
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• 2013

The present study examines a set of financial ratios in predicting the up or down movements of stock prices in the context of a securities law, the Sarbanes-Oxley Act of 2002 (SOA), controlling for macroeconomic variables. Using the logistic regression with proxy betas to alleviate the incompatibility problem between the firm-specific financial ratios and macroeconomic indicators, we report evidence that financial ratios are meaningful predictors of stock price changes, which subdue the influence of macroeconomic indicators on stock returns, and more importantly that the SOA truly improves the stock price predictability of financial ratios for the markup sample. The empirical results further suggest that industry and time effects exist and that for the markdown sample the SOA actually deteriorates the predictive power of financial ratios.