• Journal of Electrical Engineering and Technology
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• 제9권5호
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• pp.1551-1561
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• 2014

Design, Simulation and experimental analysis of closed loop time domain based Discrete PWM buck-boost converter are described. To improve the transient response and dynamic stability of the proposed converter, Discrete PID controller is the most preferable one. Discrete controller does not require any precise analytical model of the system to be controlled. The control system of the converter is designed using digital PWM technique. The proposed controller improves the dynamic performance of the buck-boost converter by achieving a robust output voltage against load disturbances, input voltage variations and changes in circuit components. The converter is designed through simulation using MATLAB/Simulink and performance parameters are also measured. The discrete controller is implemented, and design goal is achieved and the same is verified against theoretical calculation using LabVIEW.

• Journal of Electrical Engineering and Technology
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• 제3권1호
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• pp.43-51
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• 2008

Evolutionary Algorithms (EAs) cover all the applications involving the use of Evolutionary Computation in electronic system design. It is largely applied to complex optimization problems. EAs introduce a new idea for automatic design of electronic systems; instead of imagine model, ions, and conventional techniques, it uses search algorithm to design a circuit. In this paper, a method for automatic optimization of the digital circuit design method has been introduced. This method is based on randomized search techniques mimicking natural genetic evolution. The proposed method is an iterative procedure that consists of a constant-size population of individuals, each one encoding a possible solution in a given problem space. The structure of the circuit is encoded into a one-dimensional genotype as represented by a finite string of bits. A number of bit strings is used to represent the wires connection between the level and 7 types of possible logic gates; XOR, XNOR, NAND, NOR, AND, OR, NOT 1, and NOT 2. The structure of gates are arranged in an $m{\times}n$ matrix form in which m is the number of input variables.

• 한국의류학회지
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• 제38권6호
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• pp.810-822
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• 2014

This study investigated the effects of sociocultural influence and body image on appearance enhancement behavior (facial management, clothing selection, and weight/figure management). For data collection, a questionnaire was administrated to 378 female college students in Seoul and Gyeonggi-do from May $23^{rd}$ to June $10^{th}$ 2013. A SPSS 18.0 statistics package was used to analyze data along with descriptive statistical analysis, frequency analysis, factor analysis, reliability analysis, and regression analysis and frequency analysis. The results were as follows. First, sociocultural influences were divided into three factors: media influence, peer influence, and parental influence. Overall sociocultural influences had positive effects on appearance enhancement behavior. Second, body image was divided into: appearances-management, body-satisfaction and body confidence. Sociocultural influences had a significant effect on overall body image. Third, body image positively affected overall appearance enhancement behavior.

• 전기학회논문지P
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• 제66권3호
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• pp.105-109
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• 2017

In this paper is proposed wide band reconfiguration antenna by using PIN diode. The proposed antenna consisted of elliptical dipole and exponential taper balun. The proposed new matching method was exponential tapered balun in this paper. The research paper comprised of two PIN diode and Elliptical dipole. This paper used CPW to CPS feed. We obtained a good band width characteristics result by simulating. This antenna is designed to apply ISM and WiFi band.

• 건축역사연구
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• 제21권4호
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• pp.47-58
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• 2012

The purpose of this paper is to trace the architectural origin of the Bosung College Library (1935~37), which is currently used as Graduate School Building of Korea University. So far, numerous books have repeatedly described that the library was modelled on a Duke University library, but without any serious consideration. Through literature review, field-trip and archives investigation, this research discovered new critical facts concerning the origin of the building. First, Dong-Jin Park, the architect for Bosung College, saw a photograph of the Duke library in a Duke University catalog possessed by Chun Suk Auh, Professor of the college at that time. Second, the Duke library that he saw in the catalog, which might possibly be Bulletin of Duke University (Feb. 1931), is certainly the present Perkins Library (1930) in Duke University West Campus. Third, the architect probably referred not only to the library but also to other Duke buildings such as School of Medicine and The Union, of which photographs were also published impressively in the Bulletin. Although the Bosung College Library was inspired by the Duke buildings, however, it is undoubtedly a creative design work by the architect Park. Arguably, these findings broaden our view of Korean architectural history in the modernization period, and it is more than a confirmation of just one building's origin.

• 대한간호학회지
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• 제35권1호
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• pp.56-64
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• 2005

Purpose: The purpose of this study was to verify the effect of aromatherapy massage on constipation in the elderly. Method: This study for 10 day, employed a randomized control group pretest-posttest design. The experimental group received abdominal massage using essential oils with Rosemary, Lemon, and Peppermint, and the control group received a placebo massage. To evaluate the effect of aromatherapy, the degree of constipation was measured using the CAS (constipation assessment scale) and the number of bowel movements per week. Data was analyzed by repeated measures of ANOVA using the SPSS program. Result: The score of CAS of the experimental group was significantly lower than that of the control group. In addition the average number of bowel movements in the experimental group was higher than that of the control group. The effect of aromatherapy lasted 2 weeks after treatment, while the placebo effect lasted 7~10 days after treatment. Conclusion: The finding of this study showed that aromatherapy helps relieve constipation in the elderly.

• 한국농촌건축학회논문집
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• 제24권4호
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• pp.25-32
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• 2022

The purpose of this study is to provide design guidelines necessary for creating disability-friendly campuses. To this end, a literature survey and a survey on the current educational welfare facilities for disabled college students were conducted. The fact-finding survey was conducted in writing and visiting evaluations on 19 campuses located in Gangwon-do(province). The results of this study are summarized as follows: 1) The college enrollment rate of the disabled has doubled since 2000, but it was found to be half of the enrollment rate based on school enrollment, and the number of students who gave up in the middle is increasing. This is due to an obstacle in the learning environment, so it is necessary to improve welfare facilities. 2) As a result of evaluating the status of educational welfare support for students with disabilities, it was found that the overall evaluation result was improved, but the absolute evaluation result was less than 70%, and it was not improved. 3) As a result of evaluating the actual conditions of the intermediate facilities, indoor facilities, sanitary facilities, guidance and other facilities, and unit spaces, it is necessary to expand and improve them due to the lack of disabled parking marks, continuity of access roads, pedestrian safety passages, lifts, and rest areas for the disabled.

• Steel and Composite Structures
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• 제19권1호
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• pp.21-41
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• 2015

Push-out tests have been conducted on 18 rectangular concrete-filled steel tubular (CFST) columns with the aim of studying the bond behaviour between the steel tube and the concrete infill. The obtained load-slip response and the distribution of the interface bond stress along the member length and around the cross-section for various load levels, as derived from measured axial strain gradients in the steel tube, are reported. Concrete compressive strength, interface length, cross-sectional dimensions and different interface conditions were varied to assess their effect on the ultimate bond stress. The test results indicate that lubricating the steel-concrete interface always had a significant adverse effect on the interface bond strength. Among the other variables considered, concrete compressive strength and cross-section size were found to have a pronounced effect on the bond strength of non-lubricated specimens for the range of cross-section geometries considered, which is not reflected in the European structural design code for composite structures, EN 1994-1-1 (2004). Finally, based on nonlinear regression of the test data generated in the present study, supplemented by additional data obtained from the literature, an empirical equation has been proposed for predicting the average ultimate bond strength for SHS and RHS filled with normal strength concrete.

• Nutrition Research and Practice
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• 제5권6호
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• pp.540-547
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• 2011

High consumption of fruits and vegetables has been suggested to provide some protection to smokers who are exposed to an increased risk of numerous cancers and other degenerative diseases. Carrot is the most important source of dietary ${\beta}$-carotene. Therefore, the objective of this study was to investigate whether carrot juice supplementation to smokers can protect against lymphocyte DNA damage and to compare the effect of supplementationof capsules containing purified ${\beta}$-carotene or a placebo (simple lactose). The study was conducted in a randomized and placebo-controlled design. After a depletion period of 14 days, 48 smokers were supplemented with either carrot juice (n = 18), purified ${\beta}$-carotene (n = 16) or placebo (n = 14). Each group was supplemented for 8 weeks with approximately 20.49 mg of ${\beta}$-carotene/day and 1.2 mg of vitamin C/day, as carrot juice (300 ml/day) or purified ${\beta}$-carotene (20.49 mg of ${\beta}$-carotene, 1 capsule/day). Lymphocyte DNA damage was determined using the COMET assay under alkaline conditions and damage was quantified by measuring tail moment (TM), tail length (TL), and% DNA in the tail. Lymphocyte DNA damage was significantly decreased in the carrot juice group in all three measurements. The group that received purified ${\beta}$-carotene also showed a significant decrease in lymphocyte DNA damage in all three measurements. However, no significant changes in DNA damage was observed for the placebo group except TM (P = 0.016). Erythrocyte antioxidant enzyme was not significantly changed after supplementation. Similarly plasma lipid profiles were not different after carrot juice, ${\beta}$-carotene and placebo supplementation. These results suggest that while the placebo group failed to show any protective effect, carrot juice containing beta-carotene or purified ${\beta}$-carotene itself had great antioxidative potential in preventing damage to lymphocyte DNA in smokers.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제44권3호
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• pp.103-106
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• 2018

Objectives: The goal of the study was to investigate the clinical effects of amoxicillin-clavulanic acid (500+125 mg) with metronidazole 400 mg administered three times daily (Group I) versus azithromycin 500 mg administered once daily and with metronidazole 400 mg three times daily (Group II) for the prevention of postoperative infection following mandibular third molar surgical removal. Materials and Methods: The study design was a single-center prospective study. Patients who reported to the Department of Oral and Maxillofacial Surgery between February 2015 and January 2017 for removal of mandibular third molar were screened, and 108 patients were chosen. One surgeon carried out all procedures. Patients were prescribed antibiotics until the two groups contained a similar number of cases. Results: Our data showed that Group II had fewer incidences of surgical site infection, but with no statistical significance. Conclusion: Although both treatments are used routinely after removal of the mandibular third molar, neither is significantly better than the other.