• 한국조리학회지
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• 제7권2호
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• pp.195-215
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• 2001

This study is of an analysis of the kinds of influences on the subordinate variables through the adjusting variables by the independent variables which serve as the perception factor of job stress. also This study, with taking the workers for the hotel employees who are in the room, food & beverage and cook, was carried out so as to analyze deeply and throughly the stress of work they experience in doing their job and the tension incited from this stress and the strategy used for meeting this stress to grope for raising plan for the degree of satisfaction with their job of the workers for the hotel. In order for, this study ran paralled with literature study and research study, taking 615 workers who are now working in hotel. Job stress is easily negligible in hotel business not only because it is hard to identify and measure its concrete entity on account of its intangible characteristic but also because it is impossible to check physically the relationship with each direct behavior. If job stress continue, however, it can cause neglect of duty, change of occupation, deterioration of service quality and eventually aggravate the cost of a hotel business and decrease the hotel sales. Consequently, it is highly necessary to increase job satisfaction by identifying systematically and eliminating the stress factor of hotel employees in order to accomplish particularly experience unique job stress in the course of contact since they should provide the customer with their services.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2007년도 하계학술대회 논문집
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• pp.435-437
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• 2007

Authors propose a PFC(power factor correction) Buck-Boost AC-DC converter by soft switching method. The proposed converter for a discontinuous conduction mode eliminates the complicated control requirement and reduces the size of components. The input current waveform in the converter is got to be a sinusoidal form of discontinuous pulse in proportion to magnitude of ac input voltage under the constant duty cycle switching.Therefore,the input power factor is nearly unity and the control algorithm is simple. To achieve high efficiency system, the proposed converter is constructed by using a partial resonant technique. The control switches using in the converter are operated with soft switching for a partial resonant. The control switches are operated without increasing their voltage and current stresses by the soft switching method. The result is that the switching loss is very low and the efficiency of converter is high.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 B
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• pp.1190-1192
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• 2003

This paper presents a novel single-stage high frequency resonant inverter link type DC-DC converter using zero voltage switching with high input power factor. The proposed high frequency resonant converter integrates half-bridge boost rectifier as power factor corrector (PFC) and half-bridge resonant converter into a single stage. The input stage of the half-bridge boost rectifier is working in discontinuous conduction mode(DCM) with constant duty cycle and variable switching frequency. So that boost converter make the line current follow naturally the sinusoidal line voltage waveform. Experimental results have demonstrated the feasibility of the proposed DC-DC converter. This proposed converter will be able to be practically used as a power supply in various fields as induction heating applications, DC-DC converter etc.

• 치위생과학회지
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• 제18권5호
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• pp.280-287
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• 2018

Dental hygienists are important members of any dental clinic. They are recognized as reflecting the dental clinic's image because they spend a lot of time with patients. The longer the dental hygienist is employed, the better the relationship with the patients and the medical service provided. The purpose of the present study was to develop a scale to measure factors of long-term employment among dental hygienists. The basic questions were constructed by analyzing tools used to measure job embeddedness and satisfaction. Forty-one questions were developed that measured organizational fit (13), interpersonal relationships (8), job satisfaction (7), duty satisfaction (6), recognition (4), and self-esteem (3). A questionnaire survey was conducted, and the responses from 297 dental hygienists in dental clinics, after the exclusion of 20 incomplete surveys, were used for the exploratory and confirmatory factor analyses. As revealed by exploratory factor analysis, long-term employment intention was composed of 7 factors consisting of 29 items after the exclusion of 12. The subsequent confirmatory factor analysis revealed 4 factors ("organizational fit," "professional identity," "job connectivity," and "interpersonal relationship") consisting of 16 items, after the exclusion of 13. $Cronbach^{\prime}s\;{\alpha}$ were 0806, 0.836, 0.700, and 0.684 for the four factors. This study is meaningful in that it developed a long-term employment factor measurement tool that can be applied to domestic dental hygienists. Future studies will need to focus more on professional identity and job outcomes. The results of this study and future related ones could be used to improve dental hygienist's continuous service.

• 마이크로전자및패키징학회지
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• 제15권3호
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• pp.19-25
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• 2008

본 논문에서는 고역률과 고효율로 동작하는 새로운 스텝-업 AC-DC 초퍼에 대해 제안한다. 제안한 초퍼는 전류 불연속제어로 구동되고, 스위치의 듀티율 일정제어에 의해 입력전류는 교류 입력전압의 크기에 비례된 불연속적인 정현파 형태로 주어진다. 그 결과 입력역률은 거의 단위역률로 되고, 듀티율 일정제어에 의해 제안한 초퍼는 제어기법이 간단하게 된다. 일반적으로 전류불연속 제어에 의한 초퍼의 경우, 사용된 스위치의 턴-온 동작은 영전류 스위칭으로 되는 장점이 있지만, 스위치의 턴-오프 동작은 최대 전류에서 스위칭되어 스위칭 손실을 증대시키고 스위치의 과중한 스트레스를 가져오게 된다. 이것은 AC-DC 초퍼의 효율을 저하시키는 요인이다. 본 논문에서는 부분공진기법에 의한 새로운 소프트 스위칭 회로가 설계되어 사용된 제어스위치들의 턴-온, 턴-오프 동작을 소프트 스위칭으로 만들어 초퍼의 효율을 증대시킨다.

• 환경영향평가
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• 제16권4호
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• pp.277-283
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• 2007

Since the Kyoto Protocol became into effect, Korea has been expected to be part of the Annex I countries performing the duty of GHG reduction in the phase of post-Kyoto. Therefore, it is necessary to develop emission factors appropriate to Korean circumstances. In order to develop emission factors this study utilized the CleanSYS, which is the real-time monitoring system for industrial smoke stacks to calculate the emission rate of $CO_2$ continuously. In this study, the main focus was on the power generation plants emitting the largest amount of $CO_2$ among the sectors of fossil fuel combustion. Also, an examination on the comparison of $CO_2$ emission was made among 3 generation plants using the different types of fuels such as bituminous coal and LNG; one for coal and others for LNG. The $CO_2$ concentration of the coal fired plant showed Ave. 13.85 %(10,384 ton/day). The LNG fired plants showed 3.16 %(1,031 ton/day) and 3.19 %(1,209 ton/day), respectably. Consequently, by calculating the emission factors using the above results, it was found that the bituminous coal fired power plant had the $CO_2$ emission factor average of 88,726 kg/TJ, and the LNG fired power plants had the $CO_2$ average emission factors of 56,971 kg/TJ and 55,012 kg/TJ respectably which were similar to the IPCC emission factor.

• 한국산학기술학회논문지
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• 제13권12호
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• pp.5901-5908
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• 2012

이 연구는 물리치료사 470명을 대상으로 미국물리치료사협회에서 개발한 물리치료 전문직관을 번안하여 이 측정도구의 구성타당도와 신뢰도를 알아보기 위해 실시되었다. 확인적 요인분석을 통해 구성타당도를 알아보았고, 문항내적합치도를 통해 신뢰도를 분석하였다. 번안된 물리치료 전문직관 측정도구는 모형이 적합한 것으로 나타났고(p<.05), 7개요인(역할유연성, 이타주의, 동정/배려, 우수성, 도덕성, 전문가적 책무, 사회적 책무)으로 확인되었다. 구성요인의 표준화계수는 도덕성(${\beta}$=.93), 전문가적 책무(${\beta}$=.92), 동정/배려(${\beta}$=.86) 순으로 높았다. 성별에 따른 전문직관의 차이는 없었으나(p>.05) 임상경력에 따라서는 유의한 차이가 있었다(p<.05). 또한 전문직관은 문항내적합치도가 매우 높았다(Cronbach ${\alpha}$=.80~.96). 번안된 물리치료 전문직관은 구성타당도와 신뢰도가 있는 것으로 나타났기 때문에, 물리치료 전문직관을 측정하는 도구로 유용할 것으로 여겨진다.

• 농촌계획
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• 제24권2호
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• pp.91-100
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• 2018

This study aims to identify more reasonable and efficient development plans to engage local university students in landscape improvement projects in rural areas. To survey university students, residents, administrators and experts involved in such projects on important considerations in this regard, SWOT analysis was employed to identify important factors, followed by analytic hierarchy process (AHP) to evaluate their relative importance, identify problems and suggest implications for improvement. The results are summarized as follows: the relative importance of the SWOT group was in the order of opportunity, strength, threat, and weakness. For each SWOT factor, the relative importance of strengths was in the order of students' aspiration and passion, availability of creative ideas and designs, and improved attachment to their community. The relative importance of weaknesses was in the order of the lack of spontaneous participation of residents, short preparation periods and insufficient budgets, and the lack of experience in similar projects. The relative importance of opportunities was in the order of young students' activity itself being a boost factor to the community, students' endeavors arising a consensus among residents, and students feeling a sense of duty as representatives of their school. The relative importance of threats was in the order of projects being one-shot, temporary events, immaturity, and differences in preferences between older and younger generations. To draw an overall ranking of the sub-factors evaluated, the overall relative importance of the decision-making factors was evaluated. Among the sub-factors for each SWOT group, young students' activity itself being a boost factor to the community as an opportunity factor was shown to be the most important, while the lack of experience in similar projects was shown to be the least important as administrators and experts made appropriate interventions in each stage.

• 한국컴퓨터정보학회논문지
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• 제28권12호
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• pp.231-238
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• 2023

부스트 PFC (Power Factor Correction)컨버터는 AC 입력 전류의 단일 역률과 낮은 THD (Total Harmonic Distortion)를 달성하기 위해 다양한 제어기법들이 연구되고 있다. 그중 인덕터 전류의 평균값을 전류지령에 추종하도록 제어하는 평균전류 모드 제어가 있으며 가장 널리 사용되고 있다. 하지만, 오늘날 디지털 프로세서의 발달로 고도화된 디지털 제어가 가능해지면서 부스트 PFC 컨버터의 예측제어가 관심을 받고 있다. 예측제어에는 예측 알고리즘으로 듀티를 미리 생성하는 예측전류 모드 제어 및 모델을 기반으로 한 비용함수를 선정하여 스위칭 동작을 하는 모델예측제어로 분류된다. 따라서 본 논문에서는 부스트 PFC 컨버터의 평균전류 모드 제어, 예측전류 모드 제어, 모델예측 전류 제어를 간단히 설명한다. 또한, 시뮬레이션을 통해 전체 부하 및 다양한 외란 조건에서의 전류 제어를 비교 분석한다.

• 한국진공학회지
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• 제5권3호
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• pp.229-238
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• 1996

The electromigration phenomena and the characterizations of the conductor lifetime (Time-To-Failure, TTF) in Al-1%Si thin film interconnections under D.C. and Pulsed D.C. conditions were investigated . Meander type test patterns were fabricated with the dimensions of 21080$mu \textrm{m}$ length, 3$\mu\textrm{m}$ width, 0.7$\mu\textrm{m}$ thickness and the 0.1$\mu\textrm{m}$/0.8$\mu\textrm{m}$($SiO_2$/PSG)dielectric overlayer. The current densities of $2 \times10^6 A/\textrm{cm}^2$ and $1 \times10^7 A/\textrm{cm}^2$ were stressed in Al-1%Si thin film interconnection s under a D.C. condition. The peak current densities of $2 \times10^6 A/\textrm{cm}^2$ and $1 \times10^7 A/\textrm{cm}^2$ were also applied under a Pulsed D.C. condition at frequencies of 200KHz, 800KHz, 1MHz, and 4MHz with the duty factor of 0.5. THe time-to-failure under a Pulsed D.C.($TTF_{pulsed D.C}$) was appeared to be larger than that under a D.C. condition. It was found that the TTF under both a D.C. and a Pulsed D.C. condition. It was found that the TTF under both a D.C. and a Pulsed D.C. condition largely depends upon the appiled current densities respectively . This can be explained by a relaxation mechanism view due to a duty cycle under a Pulsed D.C. related to the wave on off. The relaxation phenomena during the pulsed off period result in the decayof excess vacancies generated in the Al-1%Si thin film interconnections because of the electrical and mechanical stress gradient . Hillocks and voids formed by an electromigration were observed by using a SEM (Scanning Electron Microscopy).