• Journal of the Korean Solar Energy Society
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• v.21 no.1
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• pp.71-82
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• 2001

The heat transfer experiment in a latent heat storage tank as a solar energy storage system for the hot water supply was carried out. The latent heat storage tank was consisted of triple - tube type ; Outer shell for hot water from solar collector, PCM storage vessel in the middle of the tank and inside tube for hot water recovery. The heat storage tank has the dimension of 60 cm long and 34 cm outside diameter. Paraffin wax(m.p = 55.4C) and sodium acetate trihydrate(m.p = 58 C) were employed as the PCM this study. Experimental variables were inlet temperature and flow rate of the hot water for heat storage stage and cold water for heat recovery stage. Temperature profiles, heat transfer coefficient and the efficiency of heat storage$(Q/Q_{max})$ and heat recovery $(Q/Q_{max})$ were determined for the paraffin wax and inorganic salt respectively.

• Journal of the Korean Solar Energy Society
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• v.21 no.1
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• pp.83-91
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• 2001

The heat transfer experiment in a pilot scale latent heat storage tank as a solar energy storage system for the hot water supply was carried out. The latent heat storage tank was consisted of three parts; Outer shell for hot water from solar collector, PCM storage vessel in the middle of the tank and immersed coil in the PCM vessel for hot water recovery. The heat storage tank has the dimension of 115 cm in height and 32 cm outside diameter. Paraffin wax (m.p = 55.4C) and sodium acetate trihydrate (m.p = 58 C) were employed as the PCM this study. Experimental variables were inlet temperature and flow rate of the hot water for heat storage stage and cold water for heat recovery stage. Temperature profiles, heat transfer coefficient and the efficiency of heat storage $(Q/Q_{max})$ and heat recovery $(Q/Q_{max})$ were determined for the paraffin wax and inorganic salt respectively.

• Journal of muscle and joint health
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• v.27 no.3
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• pp.325-332
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• 2020

Purpose: This study attempted to classify the potential layer for pain in the middle-aged and elderly based on the seventh Aging Research Panel Survey (2018) data and to identify the degree of depression by potential layer. Methods: This study used data from the 2018 Aging Research Panel Survey, whose participants included 6,890 middle-aged and elderly people. The data were analyzed using SPSS/WIN 22.0 and M-plus 8.0 for latent profile analysis. Results: In the study, Type 1 was a "general pain group", Type 2 was the "high back pain group", Type 3 was the "lower body pain group", Type 4 was the "shoulder pain group", and Type 5 was the "pain-free group", which included those who answered that there was no pain. Second, it was found that the variables such as gender, age, education, or not alone were statistically significant (p<.001). Third, the difference in income, subjective health conditions, depression according to the pain site type group were confirmed. Depression was significantly higher in the back pain group, lower body pain group, and shoulder pain group compared to the pain-free group. Conclusion: Developing integrative interventions is necessary to reduce depression using the pain coping skills in middle-aged and Elderly.

• Journal of the Korean Society of Clothing and Textiles
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• v.28 no.11
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• pp.1482-1494
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• 2004

This study identified convergent validity and discriminant validity of measurement variables by factor analysis using Spss program and tested covariance measurement model including latent variables such as the website attributes (interactivity, search and visual information of website), shopping values(utilitarian and hedonic value) and attitude toward website by AMOS program. The data were collected from a sample of 271 internet shopper of university students(male: 82, female: 189). They visited the website for apparel shopping and, after searching a casual clothing which they wanted to buy, requested to answer the questionnaire. The results were as follows: Variables that reduce validity were deleted in the several steps of factor analysis and initial measurement model testing. Final measurement model was constructed by valid variables was accepted. This measurement model will be input for testing causal research model that can explain how attributes of the website influences on consumer attitude toward the website.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.2
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• pp.137-143
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• 2003

In the forming of an integrated system of radiant floor cooling and dehumidifying, chilled coil can be used for cooling and dehumidification. Therefore, it is necessary to find the efficient control method which can eliminates latent load efficiently. This study has been conducted to find this method by dividing the dehumidification system into 3 types according to the control variables and analyzing characteristics of each system. To prevent the floor surface condensation, the amount of condensation can be manipulated by water temperatures, water flow rates in chilled coil, and air flow rates passing by it. So dehumidification system control can be divided into constant air flow control and variable air flow control. Regarding dehumidification control, variable air flow control, which eliminates latent load rather than sensible load, is preferable to constant flow control.

• Journal of Agricultural Extension & Community Development
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• v.29 no.2
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• pp.111-129
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• 2022

This study aims to classify agricultural entrepreneurship preparation patterns for middle-aged adults and to explore their demographic characteristics, occupational characteristics, and agricultural entrepreneurship related variables. The result of the study follows: first, agricultural entrepreneurship preparation patterns were divided into three types of urban-born farming, rural-born farming, retirement farming. Second, these patterns showed significant differences according to the level of demographic and occupational characteristics. Third, these patterns also showed considerable differences depending on the level of agricultural entrepreneurship expectancies, agricultural entrepreneurship volition, and agricultural entrepreneurship barriers. Based on the results, diversified agricultural entrepreneurship education programs and support measures were suggested.

• Journal of Korean Home Economics Education Association
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• v.34 no.2
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• pp.77-93
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• 2022

The purpose of this study was to identify the latent profiles according to the core competencies of middle school students and to examine whether the parent-child relationship predicts the latent profiles based on the core competencies for students defined by the Korean Ministry of Education. To achieve the purpose of the study, a total of 6,065 second-year middle school students were analyzed from the fourth year of the Korean Educational Longitudinal Study (KELS 2013), which was conducted by the Korean Educational Development Institute in 2016. The results of latent profile analysis and multinomial logistic regression are as follows. First, three latent profiles (higher competency group (19.54%), middle competency group (49.03%), and lower competency group (31.43%)) were derived according to the core competencies. For all groups, the highest competency was communication ability, and the lowest was creative ability. Second, the variables of the parent-child relationship (i.e., parental academic support, emotional support, and attachment level) were significant in predicting differences among the core competency latent profiles. In particular, the emotional support of parents was found to have the greatest influence on the core competencies of middle school students. This study identified the influence of the parent-child relationship on the development of core competencies. Further, it showed that a good family relationship is important for the holistic development of adolescents.

• Journal of The Korean Association For Science Education
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• v.17 no.3
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• pp.301-311
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• 1997

The purpose of this study is to construct a structural equation model and to analyze causal relationships among variables related to attitudes to science using structural equation modeling(SEM) with LISREL VII. The sample consisted of 483 10th grade boys from a general high school in Pusan, Korea. The questionnaires (ABC-attitude scale: affection, behavioral intention, cognition scale of attitude towards science) were developed by the researcher through a pilot study. And other instruments have modified previous ones. Five instruments were used in this study: GALT(group assessment of logical thinking), MTSlS(modified test of science inquiry skill), ABC-attitude scale, MSAS(modified scientific attitude scale), CSAT(common science achievement test). Structural equation modeling with LISREL VII($J\ddot{o}reskog$ & $S\ddot{o}rbom,$ 1993) was employed to estimate the causal inferences about hypothesized relationships among observed data sets. Three competing models consisted of five latent variable(scientific thinking ability, science inquiry skill, attitude towards science, scientific attitude, science achievement) - lP(inquiry preceding) model, AP(attitude preceding) model and AM(attitude mediating) model - were developed. Among these competing models, IP model satisfied the observed data sets. The causal relationships among "attitudes to science" and other latent variables were reliably identified. According to the results of the present study, science inquiry skill was the most significant variable that can predict science achievement. But scientific thinking ability has not directly influenced science achievement. This study suggests that inquiry based teaching-learning processes should be offered to students for improvement of science achievement. At the same time, it seems to be important to develop positive attitude towards science. Understanding of relationships among variables related to attitudes to science will be helpful to the development of science curriculum and to the design of science teaching and learning process. LISREL has been recognized as a useful approach in testing a SEM. However, in this study, LISREL approach was estimated as much more useful method for research design.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.17
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• pp.7923-7927
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• 2015

Background: The Cox PH model is one of the most significant statistical models in studying survival of patients. But, in the case of patients with long-term survival, it may not be the most appropriate. In such cases, a cure rate model seems more suitable. The purpose of this study was to determine clinical factors associated with cure rate of patients with breast cancer. Materials and Methods: In order to find factors affecting cure rate (response), a non-mixed cure rate model with negative binomial distribution for latent variable was used. Variables selected were recurrence cancer, status for HER2, estrogen receptor (ER) and progesterone receptor (PR), size of tumor, grade of cancer, stage of cancer, type of surgery, age at the diagnosis time and number of removed positive lymph nodes. All analyses were performed using PROC MCMC processes in the SAS 9.2 program. Results: The mean (SD) age of patients was equal to 48.9 (11.1) months. For these patients, 1, 5 and 10-year survival rates were 95, 79 and 50 percent respectively. All of the mentioned variables were effective in cure fraction. Kaplan-Meier curve showed cure model's use competence. Conclusions: Unlike other variables, existence of ER and PR positivity will increase probability of cure in patients. In the present study, Weibull distribution was used for the purpose of analysing survival times. Model fitness with other distributions such as log-N and log-logistic and other distributions for latent variable is recommended.

• Journal of Korean Society of Forest Science
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• v.97 no.3
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• pp.255-265
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• 2008

This study is aiming at providing the useful information for successful implementation of the forest resource promotion policy through analyzing the impacting factors and their relationships on policy accomplishment and policy effectiveness in executing the forest resource promotion policy. Interview survey was conducted on the stake-holders such as government officers and civilians who have direct or indirect influences on the establishment and execution of the forest resource promotion policy. The forest resource promotion policy was heuristically analyzed by using the LISREL (Linear Structural RELations) Model. The policy accomplishments of forest resource promotion significantly showed the positive relations with the suitability of problem recognition, the suitability of policy decision-making and rationality of policy execution, while the degree of policy support and the policy accomplishments were having significant impacts upon the policy effectiveness. Since the path coefficients between the latent variables and observed variables and among the latent variables mostly showed the positive relations significantly, the forest resource promotion policy was evaluated very successful in terms of policy accomplishments and policy effectiveness.