• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 추계학술대회 논문집 Vol.15
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• pp.111-115
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• 2002

To understand the discharge characteristics in AC-PDP, it is necessary to study on the wall charge behavior. But, it is difficult to measure the wall charge directly. In this paper, the V-Q Lissajous' figure is used to measure the wall charge indirectly and analyze the wall charge behavior. With the V-Q Lissajous' figure, the discharge characteristics of AC-PDP are studied according to vary driving conditions, such as the frequency, pulse duty ratio, and rising & falling time. As a result, the V-Q Lissajous' figure is used to measure the discharge characteristics of the AC-PDP. It is confirmed that firing initial voltage and firing final voltage for discharge are effected by the aboved variables. Related with the wall voltage generation, it is thought that the difference of the slope at the V-Q Lissajous' figure is caused by charged ions inside the dielectric layer.

• Journal of the Optical Society of Korea
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• 제15권2호
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• pp.182-186
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• 2011

A poling method using multiple negative voltage was introduced to fabricate periodically poled lithium niobate (PPLN) devices with quasi-phase matching (QPM) period of $12.9\;{\mu}m$ by utilizing an real-time visualization system. We also performed variation of the electric field during the poling. Two different conventionally used poling method, negative and positive single pulses, were used and the poling quality compared through microscopic images and far-field diffraction pattern analysis. Etched images on the +z and -z surfaces of PPLN showed that negative multiple pulse poling presented the highest periodicity in domain structures among the three methods. Duty ratio and its standard deviation were measured by analyzing far-field diffraction patterns. The newly introduced method of negative multiple pulse poling had duty ratio of 0.42 which was close to the ideal value of 0.50 and standard deviation of 0.020 that was about 3 times smaller than that of the other conventional methods.

• 전기학회논문지
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• 제61권12호
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• pp.1848-1856
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• 2012

This paper proposes a new grid-tied power conditioning system for battery energy storage, which is composed of a 2-stage DC-DC converter and a PWM inverter. The 2-stage DC-DC converter is composed of an LLC resonant converter connected in cascade with a 2-quadrant hybrid-switching chopper. The LLC resonant converter operates in constant duty ratio, while the 2-quadrant hybrid-switching chopper operates in variable duty ratio for voltage regulation. The operation of proposed system was verified through theoretical analysis and computer simulations. Based on computer simulations, a hardware prototype was built and tested to confirm the technical feasibility of proposed system. The proposed system could have relatively higher efficiency and smaller size than the existing system.

• 한국생산제조학회지
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• 제9권6호
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• pp.49-56
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• 2000

Due to the rapid increase of long-distance transportation, particular attentions have been paid to truck tires, especially to their dynamic characteristics. In this research, experimental modal analysis on two kinds of light-duty truck tires, i.e., radial tire and bias tire, are performed by using GRFP(global rational fraction polynomial) method to investigate differences of the dynamic behavior of the two tires. The test results have shown that the modal frequencies of bias tire are much higher than the corresponding values of radial tire with a similar mode shape, which is in accordance with the fact that the radial rigidity of bias tire is higher than that of radial tire. And most of the modal decay rates of bias tire are larger than those of radial tire within the scope of this experiment. In the frequency domain range of test, the bias tire has extra modes, which do not occur in the radial tire. This difference is based on the fact that the circumferential rigidity of the bias tire is quire low whereas that of radial tire is so high that the frequencies of the corresponding modes are out of the frequency range of test.

• 한국학교ㆍ지역보건교육학회지
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• 제15권3호
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• pp.95-103
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• 2014

Objectives: To identify work stress and affecting factors of the emergency medical technicians(EMT) and to provide basic data for work circumstance improvement and emergency medical service and duty efficiency elevation. Methods: The data were collected by questionnaire from 635 emergency medical technicians throughout the whole country from August 5 to September 20 2013 and analyzed by using the SPSS(version 18.0) program. Factors affecting stress were analyzed by Multiple Linear Regression Analysis(${\alpha}=0.05$). Results: Mean level of job stress was markedly high in the spot situation(3.43 point), user awareness(3.31 point), burden related to work(3.21 point), role and conflict as a professional job(3.10 point), unsuitable treatment(2.95 point) but was lowest in specialty demand of knowledge and skill(2.76 point). Conclusions: To diminish work stress, understanding and cooperation of the residents and reduction of burden related to work must be improved. Above all, positive interest of 119 and related organ and duty environment improvement will and effort and continuous measure establishment and support and cooperation of the government are needed.

• 한국병원경영학회지
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• 제27권1호
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• pp.11-19
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• 2022

Purposes: This study was to investigate intention to exercise the patient's right of self-determination on adopting the non-benefit medical services and was to identify factors associated with intention to self-determined decision. Methodology: A total of 1,000 adult respondents aged 20 to 65 years were recruited using stratified random sampling and surveyed by online. Multivariate logistic regression analysis was performed to identify factors associated with intention to self-determined decision using SAS 9.4(SAS Institute Inc. Cary, NC, USA). Findings: 61.9% of total participants(n=592) had intention to exercise patient's right of self-determination on adopting the non-benefit medical services. Significant differences were observed in the exercise of self-determination in relation to prior explanation and opportunity for self-determination. Practical Implications: This study suggested that explanation duty of provider might influence on increasing intention to exercise the patient's right of self-determination. Considering appropriate use of non-benefit services, it is important to enhance explanation duty of provider.

• The Journal of Asian Finance, Economics and Business
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• 제10권2호
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• pp.49-60
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• 2023

The study attempts to examine the relationship among revenue growth factors from different angles and provides a comprehensive overview of tax revenue collection for developing countries. The impact of income tax, customs duty, and value-added tax on the gross domestic product is examined using the ordinary least-square (OLS) multiple regression approach. To confirm the association, a multiple regression model is applied to time-series data. SPSS software, MS Excel, is used to draw the empirical results, trend analysis, and some graphical presentation to reach the study's objective. The findings show that while the value-added tax has a significant impact and the highest coefficient, regardless of country, income tax and customs duty may or may not be significant depending on the circumstances. It triggers effectual and efficacious economic growth. The paper has implications in policy-making areas where governments are seeking how to stimulate revenue growth effectively and efficiently. To promote economic growth, the tax net and tax rate on luxury goods should be increased along with human resources in the tax administration for the short term. But in the long term, decentralization & digitization of tax administration, dismantling the existing tax barriers and good governance are necessary.

• 항공우주의학회지
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• 제30권1호
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• pp.34-39
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• 2020

The medical fitness of pilots is part of the civil aviation safety scenery. This study aimed to analyze the health problems occurring among Korean commercial pilots. Three data sources were used to identify the health problems: 7,574 aviation medical examination data, 5,400 sick leaves and 39 cases of a decrease in medical fitness during flight duty period and layover of Korean commercial pilots who have been working for K airline from Jan. 1, 2016 to Dec. 31, 2018. This study was retrospectively analyzed using SPSS 22 statistical program. Waiver of medical certificates was an average 11.9% of total issuance for 3 years, with a denial of 0.1%. The leading cause of denial of medical certificates was predominantly of cardiovascular cause (55.6%). Mild respiratory and digestive disease accounted for 82% of total sick prevalence and 68% of total sick days. The psychiatric and cardiovascular disease were ranked high according to the number of days lost per case. The most common cause of decrease in medical fitness during flight duty period was acute abdominal pain (36.4%) and musculoskeletal disorder (40%) when staying abroad. Aeromedical emphasis on minimizing cardiovascular risk remains appropriate. Major pilot health problems identified in this study should be considered in establishing pilot health promotion programs for aviation safety.

• 한국콘텐츠학회논문지
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• 제10권10호
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• pp.267-273
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• 2010

본 연구는 국내 치과 병(의)원에 근무하는 중간관리자의 호칭, 업무, 월평균 소득, 지식경로, 업무 시 어려움 등의 현황을 조사하여, 중간관리자로서의 역할과 위치를 확립하는 기초자료로 삼고자 국내 치과병(의)원 중 총 108곳의 중간관리자에게 이메일을 이용한 설문지를 배포하여 중간관리자가 직접 설문에 응하도록 하였으며, 조사기간은 2008년 6월 1일부터 6월 30일까지 조사하였다. 통계분석은 SPSS 12.0 프로그램을 활용하여 카이제곱 검정과 분산분석을 실시하였으며, 무응답은 시스템 결측치로 처리하였다. 이에 다음과 같은 결과를 얻었다. 1. 직종별 구성원의 수는 병원 규모에 따라 치과병원이 구성원 수가 가장 높게 나타났으며, 구성원 중 치과위생사의 수가 치과병원에서 통계적으로 유의하게 높게 나타났다. 2. 중간관리자의 명칭은 대부분 실장으로 불리며 중간관리자로서의 경력은 치과병원은 1년에서 5년미만이 48.0%, 네트워크치과는 5년에서 10년미만이 52.9%, 치과의원은 1년에서 5년미만이 69.4%로 많았으며 통계적으로 유의하였다. 3. 업무 수행 시 지식 습득 경로는 대부분 병원 자체 세미나와 학회 세미나가 높게 나타났고, 업무 시 어려움은 치과병원에서는 원장님의 높은 기대가 네트워크치과와 치과의원은 다양한 지식습득의 어려움이 가장 높게 나타났다. 4. 중간관리자로서의 업무는 환자응대, 환자예약 및 변경, 전화업무, 치료계획 및 비용상담의 순으로 나타났다. 업무 중 병원경영, 우편물관리, 컴퓨터관리와 같은 행정업무는 낮은 비율로 나타났다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 1999년도 춘계종합학술대회
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• pp.254-260
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• 1999

유성버스트 통신방식은 1000 km 이상의 장거리 VHF NLOS 데이터 통신 시스템을 가장 경제적인 방법으로 구현 시켜줄 수가 있다. 그러나 이 방식은 도통율이 열화 함으로 본질적으로 실용에는 부적합한 것으로 알려져 있다. 송, 수신안테나의 빔 패턴이 공간의 hot-spot을 완전히 포용할 수 있도록 함으로서 버스트의 발생빈도를 증가시키는 동시에 안테나에 유도하는 지상 잡음 전계를 효과적으로 차단함으로서 수신기의 실효 차단전압을 낮추어 시스템의 도통율(duty rate)을 개선 할수 있다. 소개구형 공동형 안테나를 개발하였다. 이 안테나는 지하에 매설하여 사용하는데 이렇게 함으로서 수직방향의 지향성이 개선되고 지상으로부터의 잡음 혼입이 효과적으로 차단된다. 이 안테나는 3dB 빔 폭이 90$^{\circ}$ 에 달하여 앙각 8-90$^{\circ}$ 로서 근거리의 hot-spot를 효과적으로 조사(illuminate) 할 수가 있다. 지표방향으로의 지향성은 최소로 억제되어 이 방향으로부터 인공잡음의 혼입을 효과적으로 차단하는데 재래식의 Yagi 보다 평균 3 dB 이상 억제된다. 이 안테나를 수신안테나로 사용하여 100 km 경로에서 시험통신을 실시한 결과 동일한 조건하에서 4 소자 Yagi 안테나를 사용한 경우에 비하여 버스트의 발생빈도와 지속시간이 각각 10%와 20% 이상 증가한 것을 확인할 수 있었다.