• The Transactions of the Korean Institute of Power Electronics
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• v.27 no.3
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• pp.180-191
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• 2022

In this paper, a single-stage alternating current (AC)-DC converter is proposed for the automated-guided vehicle wireless charging system. The proposed converter is capable of soft-switching under all input voltage (VAC: 220 Vrms ± 10%), load conditions (0-1 kW), and air gap changes (40-60 mm) by phase control at a fixed switching frequency. In addition, controlling a wide output voltage (Vo: 39~54 VDC) is possible by varying the link voltage and improving the input power factor and the total harmonic distortion factor. Experimental results were verified by making a prototype of a 1-kW wireless power charging system that operates with robustness to changes in air gaps.

• The Korean Journal of Elementary Counseling
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• v.10 no.2
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• pp.185-201
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• 2011

The purpose of this study is to reveal and confirm the factor structure inherent in the Korean inventory of peer relationships(KIPR; Sang-Hwang Hong, et al., 2009) in order to strengthen the interpretive usefulness of the test. For this purpose, the inventory was administered to the total of 616 children in the fourth through sixth grades in three elementary schools located in Gyungnam area, and the data from 578 of them were analyzed. The results of the study can be summarized as follows. First, as a result of the exploratory factor analysis of 3-factor and 4-factor models, the 3-factor model was found to be more appropriate. In the 3-factor model, the factor 1 is named "Lack of Self-Confidence and Social Withdrawal" as it consists of such circumplex scale items as Non-Assertiveness (C5), Social Avoidance (C4), the Cold (C3), and Too Submissive (C6). The factor 2 is named "Too Aggressive and Controlling" and consists of items Too Controlling (C1) and Hard to be Supportive (C2). The factor 3 is named "Too Caring" and consists of items Too Responsible (C7), Over Involvement (C8), and Too Submissive (C6). Second, as a result of the confirmatory factor analysis, the 3-factor model, in comparison to the 4-factor model, was found to better reflect the collected data(RMSEA=.054), its goodness of fit was not satisfactory but within the acceptable range(CFI=.786), and its power of simplicity and clarity was also adequate(PCFI=.733). In the current study, through the exploratory and confirmatory factor analyses of scores from the Korean inventory of peer relationships circumplex scales, scales within the peer relationship circumplex model that are near each other and are highly correlated were confirmed to be grouped together as same factors. I believe the main merit of the study lies in the above result having provided the necessary foundation for forming the superordinate and representative scale that encompasses the eight circumplex scales, which enhances the test's interpretive usefulness.

• Journal of the Korean Geographical Society
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• v.39 no.5 s.104
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• pp.722-734
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• 2004

Longitudinal profiles of bedrock rivers play a fundamental role in landscape history by setting the boundary conditions for landform evolution. Longitudinal profiles are changed with climatic conditions, lithology and tectonic movements. Tectonic movement is an important factor controlling longitudinal profiles, especially in tectonically active area where uplift rates are regarded as a major factor controlling channel gradient. However study on bedrock channel has made little progress, because controls over bedrock river incision are yet to be clarified. Previous numerical simulations have used a simple diffusion model, which links together the overall processes of bedrock channel erosion as in other landform evolution models. In this study, previous bedrock incision models based on physical processes (especially abrasion) are reviewed and new modifications are introduced. Using newly formulated numerical model, the role of spatial pattern and intensity of tectonic uplift on changes in river longitudinal profile was simulated and discussed.

• Anxiety and mood
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• v.16 no.2
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• pp.91-97
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• 2020

Objective : The suicide mortality rate among Koreans was ranked first among the OECD countries in 2018. Alcohol consumption is a significant risk factor for suicidal behavior. This study examined the relationship between the severity of subjects' drinking habits and the suicidal ideation among Koreans according to gender and age. Methods : The data of 113,602 people who visited the Kangbuk Samsung Hospital Health Screening Center from January 2013 to December 2014 were used. The severity of subjects' harmful drinking habits was assessed using the Korean version of the Alcohol Use Disorders Identification Test (AUDIT-K). The relationship between the severity of harmful drinking and suicidal ideation was compared using logistic regression analyses. We also examined the tendency through p for trend to identify a trend. Results : Of the 113,602 study subjects, 6,586 (5.8%) responded that they had thought of committing suicide. After controlling for gender, marriage, education, body mass index (BMI), depression and anxiety, the results showed that the higher the level of harmful drinking, the higher the suicidal ideation. Conclusion : This study found that, even after controlling depression and anxiety, the severity of drinking could be a significant risk factor for suicidal ideation.

• Anxiety and mood
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• v.16 no.1
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• pp.1-8
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• 2020

Objective : This study aims to examine the association between exposure to suicide events and suicide ideation by analyzing the levels of suicide ideation among the groups with exposure to suicide death, non-suicide death, and no death in their social relationships. Methods : Data were derived from Wave I of the Longitudinal Study of Suicide Survivors' Mental Health. 1,998 adults nationwide selected using a stratified sampling method based on the Korean Census Data, were categorized into 3 groups with exposure to suicidal death, non-suicidal death, and no death. The levels of depression (Brief CES-D), subjective health status, and suicidal ideation (SSI) were measured. To examine the association between exposure to suicide and the level of suicide ideation, multiple regression analysis was used after controlling the socio-demographic and clinical factors including subjective health status and depression. Results : 32% reported their exposure to suicide. Compared to the other groups, the suicide-exposed group's level of depression and suicide ideation were significantly higher but the subjective health status was lower. Multiple regression model revealed that suicide exposure had a statistically significant association with suicidal ideation at p=0.000 even after controlling the clinical characteristics. Conclusion : HThe findings suggest that exposure to suicide is a risk factor for suicidal ideation. In the clinical field, it is necessary to consider patients' experience in exposure to suicide while treating and intervening in suicide-related cases. At the policy level, a mental health system for suicide prevention should consider this risk factor for those exposed to suicide in their family and social relationships.

• Journal of Digital Convergence
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• v.12 no.11
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• pp.365-372
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• 2014

In this paper, We implement a power-saving and efficient measures in buildings using the smart-meter. In order to save electric power energy, We propose an improved automatic power-factor controller(APFC) and demand control measures. This is achieved by controlling directly circuit breakers and the capacitor bank feeders in real time via a two-way smart-meter's ICT skills. Improved APFC is minimizing installation costs by series-parallel connecting heterologous capacitors to form a more diverse capacitor banking and controlling using the smart-meter. In order to suppress the demand power, We have designed a smart-meter with communication functions using Atmel's AVR465 and tested an operated lodging building for 24-hours. As a result, We made sure to always retained more than 95% power factor and did not occur over compensation.

• Journal of The Korea Institute of Healthcare Architecture
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• v.30 no.3
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• pp.45-56
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• 2024

Purpose: It is important to note that the relative importance of risk factors should be identified to successfully complete the remodeling project of general hospital. Approached by analytic hierarchy process (AHP), the present study aimed to systematically evaluate the risk factors for remodeling of general hospital. Methods: The present work classified the risk factors of general hospital remodeling into four major categories including the requirements survey stage, planning and design stage, dismantling and construction stage, and maintenance stage. In addition, four sub-categories were derived from each major category factor. Furthermore, five major categories and four subcategories were selected to be considered from the perspectives of two stakeholders of contractor and constructor. The relative importance of the major and sub-categories factors was calculated using the AHP technique on the survey data collected from 49 respondents who participated in the survey study. Results: The results indicate that, the risk factor of requirements survey stage was found to be the most important risk factor to consider among the four major categories of factors. Also, insufficient preliminary investigation, design inconsistencies in architecture/mechanics/electricity, occurrence of safety accidents, and insufficient review of various equipment capacities and performances were found to have the highest priorities of each subcategory factor group included in the four major categories. From the perspective of contractor, the error in predicting the construction period was found to be the most important risk factor. The occurrence of safety accidents during construction was found to be the most important risk factor to be considered by constructor. Implications: The result of the current work should provide important insights and guidelines for the risk management activity that contributes to controlling the project time, cost, and scope required for general hospital remodeling.

• Nutritional Sciences
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• v.8 no.1
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• pp.35-41
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• 2005

Controlling dietary behaviors and health-related lifestyle habits is important to manage non-insulin dependent diabetes mellitus (NIDDM). If NIDDM is not treated properly, the prevalence of macro-vascular complications (MC) may increase. The goal of NIDDM therapy is to maintain normal concentrations of blood glucose and lipid profiles by having regular meals, controlling alcohol drinking, quitting smoking, and performing physical exercise regularly. This study was performed to investigate the dietary and health-related lifestyle habits and blood parameters of NIDDM patients of both genders and compared these characteristics between the patients with and without MC. Our results show that the subjects with MC compared to without MC and the female patients than the males controlled their diets more regularly, tended to regulate the number of meals better, and smoke less than those without MC. Although plasma lipid profiles were not significantly different between the genders and between the subjects with and without MC, the men had higher blood glucose and plasma tHcy concentrations than the women and plasma tHcy concentration was higher in the female subjects without MC. These results imply that the male patients of NIDDM without MC might have more problems in maintaining their blood glucose. In addition, smoking may be the most important life-style factor influencing some blood parameters like blood glucose, HbAlc, and total cholesterol in the NIDDM patients.

• Journal of the Korean Society of School Health
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• v.21 no.2
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• pp.23-33
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• 2008

Purpose: Internet is one of the essential tools in South Korean adolescent life. Recently, researchers suggest that Internet use is positively associated with teens' mental health problems such as depression and suicide. Thus, this study explored a relationship between Internet use and suicide ideation among South Korean adolescents. Methods:　Secondary data, the three-wave Korean Youth Panel Survey, were analyzed. First, in terms of the levels of Internet use and suicidal ideation, t-test was used for examining a gender difference, and Analysis of Variance were used for examining differences across three points in time(waves 2 - 4). Second, logistic analysis was performed to examine the significant association between Internet use and suicide ideation after controlling for the other factors' effects. In this analysis, Fixed Effect Regression Method(FERM) was incorporated as well. FERM was useful in adjusting for the effects of time-invariant factors even without measuring them. As a result, it was possible to obtain more accurate findings. Results: Adolescent depression was an important factor influencing the association between Internet use and suicide ideation. After controlling for the effect of depression, the relationship between Internet use and suicide ideation was no longer statistically significant. Conclusion:　As a proxy to identify teens who are obsessed with suicide ideation, levels of Internet use do not seem useful. Instead, it is necessary to examine teens' access to websites related to suicide.

• Tribology and Lubricants
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• v.35 no.6
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• pp.350-355
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• 2019

Surface energy is an important factor in determining the performance of application components in terms of preventing adhesion failure between thin films. In this regard, numerous attempts have been made to acquire the desired surface energy through chemical treatment or by using micro/nanostructures. However, such approaches are expected to provide extreme values of surface energy, which may not be suitable in achieving the enhanced performance of applications. In this study, we propose a method to control surface energy by using bilayer metallic film heterostructures. We measure the water contact angle of incompatible (Ni/Ag) and compatible (Zn/Ag) metal pairs under several experimental factors, including thickness, time, and temperature. Furthermore, we conduct Auger electron spectroscopy measurements to investigate the atomic concentration with respect to depth after the change in the water contact angle. The experimental results reveal that three parameters, namely, compatibility, film thickness, and environmental temperature, are major factors in controlling the water contact angle. Thus, we experimentally demonstrate that controlling these three parameters can provide the approximate desired water contact angle. This result is expected to aid in the performance enhancement of a wide range of application components, where control of surface energy is required.