• Korean Journal of Biological Psychiatry
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• v.17 no.4
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• pp.218-225
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• 2010

Objectives : The potential association between choline acetyltransferase(CHAT) polymorphism and the risk of mild cognitive impairment(MCI) has not been investigated in Korea. We examined the main effect of CHAT polymorphism and its interaction with apolipoprotein E(APOE) polymorphism in the development of MCI in elderly Korean sample. Methods : We analyzed CHAT 2384G > A polymorphism and APOE polymorphism among 149 MCI subjects with MCI and 298 normal controls. We tested the association between MCI and CHAT A allele status using a logistic regression model. In addition, we employed generalized multifactor dimensionality reduction(GMDR) to investigate the interaction between CHAT and APOE with regard to the risk of MCI. Results : The CHAT A allele was associated with AD risk(OR = 1.59, 95% CI = 1.02-2.48, p = 0.042). No significant gene-gene interaction between CHAT and APOE was found in GMDR method(testing balanced accuracy = 0.540, p = 0.055). Conclusion : The CHAT A allele was associated with MCI risk in the Korean elderly. Its interaction with the APOE ${\varepsilon}4$ allele was not significant with regard to the development of MCI.

• Journal of the Semiconductor & Display Technology
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• v.10 no.1
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• pp.43-49
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• 2011

In this study, the dynamic characteristics of an air spring connected with an external chamber through a flexible tube are examined. The uncoupled dynamic parameters of the air spring are identified through experiments, followed by the suggestion of a model-based approach to obtain the remaining coupled dynamic parameters using the various frequency response functions derived in PART I paper [1]. To improve or control the damping characteristics of the air spring, this vibration isolation air spring system is physically established in laboratory scale. And we attempt to identify various parameters used to describe to air spring system by both theoretically [1] and experimentally, which is performed in this report. The damping parameter of the tube system is identified through experiments on the system incorporated with the air cylinder, and a nonlinear regression procedure is employed to find solutions. The resulting value is used to expect the frequency response function of dynamic pressure in the top chamber (air spring) with respect to that in the bottom chamber (external chamber). Comparison with the experimental data supports the validity of the present estimation procedures. Also, the dynamic mechanism of the damping effects particularly in a low frequency range is investigated through this experimental endeavor.

• International Commerce and Information Review
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• v.14 no.4
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• pp.153-174
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• 2012

The purpose of this study is to analyse factors affecting performance of Global Outsourcing of the Korean Export-Importing Companies. This study aims to confirm the cause and effect relationship between independent variables; Organization Competency, Flexibility, Information Sharing and Partnership and dependent variable; the performance of Global Outsourcing. Also, another objective of this study is to discover affecting levels for the performance and activation factors of global outsourcing and to contribute to diffusion of global sourcing. This paper examined the concept and features of global sourcing and the present situation of global outsourcing at the level of domestic and overseas. From precedent studies that based on empirical studies about the transaction theory and the resource-based theory, we have derived a model with hypothesis and scale items then we conducted a survey of the Korean Export-Importing companies and empirically analysed the data. Before hypothesis testing, we conducted a basic information analysis in order to discover implication level of Global Soucring and also did reliability analysis and exploratory factor analysis using SPSS 18.0. Finally, the four hypothesis for the performance of Global Sourcing were tested with a regression model.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.3
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• pp.153-162
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• 2013

Most test methods for plant available soil phosphate are based on the extraction with a chemical solution. The objective of this study is to evaluate available phosphate of various tests at different soil phosphate levels. Two experiments were conducted as follows: i) Extracting capacities of soil phosphate tests - Mehlich III, Mehlich II, Bray I, Olsen, Kelowna, and Modified Lancaster(Mod. Lancaster) - were compared with that of Lancaster test for the soils collected from 32 paddy and 27 upland fields with various soil chemical properties. ii) Field trials on comparing to phosphate uptake by plant were accomplished by cultivating rice and corn plants in the pots filled with the soils. Available phosphate of Lancaster test was significantly correlated with those of Mehlich III, Mehlich II, Bray I, Olsen, Kelowna, and Mod. Lancaster. In upland soils, available phosphates of all the tests were curvilinearly regressed with phosphate uptake by corn. The determination coefficients ($R^2$) of the regression equation between available phosphate in soils and phosphate uptake by plants were ranged from 0.861 (Mehlich III) to 0.741 (Olsen). In paddy soils, the available phosphate measured by Mehlich III and Lancaster was significantly correlated with phosphate uptake by rice. In conclusion, Lancaster and Mehlich III tests could be used for predicting available phosphate in upland and paddy soils.

• The Korean Journal of Applied Statistics
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• v.18 no.3
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• pp.503-519
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• 2005

Cointegration test is usually performed under the assumption that the cointegrating vector is constant for the whole sample period. Most previous studies have used conventional cointegration methods in testing for a stable long-run equilibrium relation among related variables. However they have overlooked that the long-run equilibrium may not the unique and the stable relation may not be guaranteed. This study develops the additional statistical tests for the stability of the estimated cointegrating vector. Three tests for the parameter stability of a cointegrated regression model are utilized and applied to identify the types of variations in the long-run relation between the domestic unemployment and the rotated macroeconomic variables of interest. The present paper finds that, there exists a stable but, time-varying long-run relation between those. The observed variation in cointegrating relations is generally characterized by a discrete one-time shift, rather than a gradually evolving random walk process which is attributable to the IMF financial and economic crisis.

• Journal of the Korea Concrete Institute
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• v.13 no.4
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• pp.305-313
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• 2001

Conductivity is an important thermal property which governs heat transfer in a solid medium. Generally, the determination of conductivity in concrete is very difficult, because concrete is a heterogeneous material composed of cement, water, aggregate, et cetera and time dependent material of which properties change with curing age. In this study, influencing factors on thermal conductivity of concrete are quantitatively investigated by QTM-D3, a conductivity tester developed in Japan. Then, a prediction equation of thermal conductivity of concrete is suggested from the regression analysis of test results. To consider the factors influencing thermal conductivity of concrete, mortar, and cement paste, seven testing variables (age, amount of cement, types of admixtures, amount of coarse aggregate, fine aggregate ratio, temperature, and humidity condition) of the specimens are used. According to the experimental results, the amount of coarse aggregate and humidity condition of specimen are the main factors affecting the conductivity of concrete. Meanwhile, the conductivity of mortar and cement paste is strongly affected by the amount of cement and types of admixtures. However, the curing age has minor effect on the conductivity variation. Finally, the prediction formula of concrete conductivity as a function of aggregate amount, fine aggregate ratio, specimen temperature, and humidity condition is developed.

• Journal of Information Science Theory and Practice
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• v.4 no.2
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• pp.34-52
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• 2016

This study was designed to investigate organizational culture and emotional intelligence as predictors of job performance among library personnel in Edo state, Nigeria. The survey research design was employed for the study with a population size of 181 library personnel in the 15 academic libraries under study, and due to the manageable population size, total enumeration was adopted as the sampling technique. The questionnaire was used to elicit data from the respondents. Of the 181 copies of the questionnaire administered, 163 copies were retrieved and found valid for analysis constituting a 90% response rate. Four research questions and four null hypotheses (tested at 0.05 level of significance) were formulated to guide the study. The tool used to analyze the research question was descriptive statistics (percentage, mean, and standard deviation) and inferential statistics (correlation and multiple regression) for testing the hypotheses. The findings of the study revealed that there is a high level of job performance, good organizational culture, and high level of emotional intelligence among the personnel. Organizational culture and emotional intelligence jointly and significantly predict job performance of personnel. There is significant positive correlation between organizational culture and job performance. The linear combination of emotional intelligence and organizational culture predict job performance of library personnel in the academic libraries under study. The research concludes that there is a need for high job performance in libraries which is predicted by the organizational culture of the library and the level of emotional intelligence of the library personnel.

• Journal of Animal Science and Technology
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• v.46 no.5
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• pp.707-718
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• 2004

This study was conducted to evaluate the adequacy of an alternative a.m. - p.m. testing scheme for milk yield in comparison with the official test method based on weighing two milkings within 24 h. A total of 8,309 p.m. milking weights and 6,767 am. milking weights from 72 Holstein cows raised at N.L.R.I. were collected between October 2000 and November 2001. Seven statistical models were fitted to the data to derive formulas for estimating daily milk yields from morning or evening yields. In general, use of evening milkings less accurately estimated than did use morning rnilkings. Although the models do not differ much in the correlations between estimated and true daily milk yields, systematic under- and overestimation of daily milk yields were observed in all models with the exception of model 7, which accounted for heterogeneous variances by parity class, milking interval class, and lactation stage by fitting separate regression formulas within each combination of three factors.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.2
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• pp.1240-1252
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• 2015

The purpose of this study was to investigate feeding difficulty and its influencing factors of elders with dementia in long-term care facilities. Participants were 158 elders with dementia residing in three nursing facilities. Data were collected from Aug. 18 to Sep. 12 in 2014. The feeding difficulty in dementia scale, Korean version-Activities of Daily Living and Mini-Mental State Exam-Korean version were used as instruments. Data were analyzed using descriptive statistics, t-test, ANOVA, Pearson correlation and stepwise multiple regression by SPSS 17.0. Mean feeding difficulty score was $0.62{\pm}0.43$(range of 0-2). The highest feeding difficulty item was "patient require close supervision while feeding". The variables influencing the feeding difficulty was ADL(${\beta}=.312$), cognitive function(${\beta}=-.172$) which explained about 20.0% of total variance. The results suggest the need of developing feeding difficulty coping strategy according to dietary behavior phase, In addition, the development and testing the educational program for caregivers to help feeding difficulty of the elders with dementia in long-term facility are recommended.

• Journal of the Korean Society of School Health
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• v.28 no.3
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• pp.150-157
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• 2015

Purpose: The purpose of the study was to survey male high school students on their MERS(Middle East Respiratory Syndrome)-related knowledge, risk perception, and health behaviors and to identify the factors affecting health behaviors during the MERS outbreak in Korea. Methods: The subjects in this study were 144 students in a male high school. Data were collected through self-reported questionnaires in July, 2015. The collected data were analyzed by ANOVA, Pearson's correlation and multiple regression using SPSS/WIN 21.0. Results: The proportion of correct answers to questions testing MERS-related knowledge was 71.6% among male high school students; their health behaviors were rated at 48.9%; and their risk perception rate was 1.8 out of 4. There was a positive correlation between knowledge, risk perception, and health behaviors. Knowledge and risk perception explained 15.1% of the variance in health behaviors. Conclusion: To improve students' health behaviors, their risk perception and knowledge over MERS should be strengthened. Therefore, it is necessary to develop and implement efficient and feasible MERS education programs for high school students.