• 한국자동차공학회논문집
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• 제21권6호
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• pp.123-134
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• 2013

Strengthening vehicle emission regulation is one of important policies to improve air quality in urban area. Due to the limitation of specified driving cycles for certification test to reflect real driving conditions, additional off-cycle emission regulations have been adopted in US and being developed in Europe. The driving cycles of US or Europe have been used in emission certification for Korean light-duty vehicles, but it has not been known how well the driving cycles reflect various real driving patterns in Korea. In that point of view, it is required to estimate vehicle emission based on real road driving conditions to raise the effectiveness of vehicle emission regulation in Korea. In this study, real driving emission measurements have been conducted for three Korean light-duty vehicles with PEMS. The driving routes consisted of urban, rural and motorway in Seoul and Incheon. The data have been analyzed with various averaging methods including moving averaging windows method and compared to emission limits set with emission certification modes applied to tested vehicles. The results have shown that the real driving pollutant emissions of a gasoline and a LPG vehicles have been ranged quite lower than those of emission limits on CVS-75 driving cycle. But real driving NOx of a light duty diesel vehicle has been considerably higher than emission limit of NEDC driving cycle. The higher than expected NOx emission of a diesel vehicle might be caused by different strategy to control EGR in real driving condition from NEDC driving.

• 대한교통학회지
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• 제31권5호
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• pp.60-70
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• 2013

본 연구는 신호 교차로에서 대형 화물차의 정지로 인해 야기되는 온실가스 배출과 교차로 효율 저하를 완화하기 위해 좌회전 현시의 대형 화물차 대상 우선신호 알고리즘을 제안하고 효과를 분석한다. 대형 화물차의 진입 속도와 좌회전 속도를 고려한 녹색신호 연장 기법을 적용하며, 우선신호 제공으로 인해 발생할 수 있는 일반차량의 지체 증가를 완화하기 위해 두 가지 보상 전략을 수립하여 비교한다. 제안된 알고리즘의 효과를 분석하기 위해 PARAMICS를 이용한 시뮬레이션 분석을 수행하며 Comprehensive Modal Emissions Model (CMEM)을 이용하여 온실가스 배출량을 산정하였다. 실제 교통망의 3지 신호교차로를 대상으로 분석한 결과 비첨두시에는 대형 화물차에 능동적 보상 전략을 통해 지속적으로 우선권을 부여하는 것이 온실가스 및 연료소모량 감축에 효과가 있는 것으로 분석되었으며, 대형 화물차의 정지 감소로 인해 총통행시간도 개선되는 것으로 나타났다. 이러한 결과로부터 제안된 알고리즘은 교통량이 많지 않은 공단 입구의 좌회전 현시에 효과적으로 적용될 수 있을 것으로 판단된다.

• 한국병원경영학회지
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• 제9권2호
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• pp.1-22
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• 2004

This study was designed to suggest a learning organization in a medical center by examining the factors to influence effectiveness of the learning organization. We collected the data of 586 persons who participated once or more times in the learning organization managed from 2000 to 2002 by Y Medical Center located in Seoul, and included the data of 285 persons in the final analysis. The results of the study are summarized as follows. First, as the results of examining the regression coefficients to predict the effectiveness of and satisfaction with the learning organization through the learning level, learning method and learning organization constructing level as the general variables, the important influential factors were shown as follows: 1)knowledge creation, knowledge storing, private learning, organizational learning, and learning organization construction of occupational and human levels as the factors to predict the working competency; 2) learning organization construction of the human level as the factors to assume the duty satisfaction; 3) gender, working years, private learning, team learning and organizational construction level for the prediction of the organizational commitment; and 4) medical technical service, knowledge creation, organization learning, and constructing level of the environmental and human levels for the assumption of the satisfaction with experience in the learning organization. Based on the study results of the effects in managing the learning organization, we can conclude the followings. First, the members who are in various working positions and occupations need to continuously participate in the learning organization. Second, to raise the organizational outcome from the management of the learning organization, it is necessary to establish systematic concepts in the constituents of the organizational effectiveness such as working competency improvement, duty satisfaction and organizational commitment, and the experience satisfaction of the learning organization. Finally, the future of the organization depends on the learning competencies of the organization members. To continuously exist and develop the organization, the private learning of the organizational members should be constantly spread and shared over the organizational level, and the usual innovations such as repetitive and habitual organizational learning should be generally tried out throughout the whole field of the management.

• 한국컴퓨터정보학회논문지
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• 제21권9호
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• pp.127-137
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• 2016

This study is an objective research to verify causality between social worker's social capital and OCB in Jeon-nam province including Kwangjoo. Survey was done directly from 255 social workers working in social welfare facilities. Study methodology was the structural equation to verify the influence of social capital on organized citizens' activities and the mediator effect of job satisfaction and organizational commitment. Using Fornell and Locker's two-step approach, this study verified the similarity between direct effectiveness and indirect effectiveness through bootstrap. I hope that the result of this study will be used as objective and academic material for social workers who work hard with sense of duty at field and expect that there will be a intensive follow-up research which can make social workers' social capital and make it stronger.

• Journal of Power Electronics
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• 제15권3호
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• pp.577-586
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• 2015

The combination of voltage feedforward and feedback control is a conventional approach for correcting the power factor in single-phase ac-dc boost converters. The feedback duty ratio increases significantly with an increase of the line frequency and input inductance. Therefore, the performance of the conventional approach is highly dependent on the bandwidth of the feedback controller. As a result, the input power quality can be significantly exacerbated due to uncompensated duty ratios if the feedback controller is limited. This paper proposes an input impedance and current feedforward control method to reduce the control portion of the feedback controller. The findings in this paper are 1) the theoretical derivation and analysis of variations of line frequency and input inductance on a power factor correction approach, 2) guaranteed consistent performance in a wide range of conditions, and 3) that a low switching frequency can be utilized by the proposed method. A MATLAB/Simulink model and a 1.2kW dual boost converter are built to demonstrate the effectiveness of the proposed method.

• Journal of Power Electronics
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• 제18권2호
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• pp.395-406
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• 2018

Marine controlled-source electromagnetic transmitters (MCSETs) are important in marine electromagnetic exploration systems. They play a crucial role in the exploration of solid mineral resources, marine oil, and gas and in marine engineering evaluation. A DC-DC controlled-source circuit is typically used in traditional MCSETs, but using this circuit in MCSETs causes several problems, such as large voltage ringing of the high-frequency diode, heating of the insulated-gate bipolar transistor (IGBT) module, high temperature of the high-frequency transformer, loss of the duty cycle, and low transmission efficiency of the controlled-source circuit. This paper presents a clamping-diode circuit for MCSET (CDC-MCSET). Clamping diodes are added to the controlled-source circuit to reduce the loss of the duty ratio and the voltage peak of the high-frequency diode. The temperature of the high-frequency diode, IGBT module, and transformer is decreased, and the service life of these devices is prolonged. The power transmission efficiency of the controlled-source circuit is also improved. Saber simulation and a 20 KW MCSET are used to verify the correctness and effectiveness of the proposed CDC-MCSET.

• 한국산업보건학회지
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• 제23권4호
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• pp.374-383
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• 2013

Objectives: The major objective of this study is to review overall and in detail the Corporate Manslaughter and Corporate Homicide Act 2007 in the U.K.and the principal contents of this act. Methods: A variety of articles related to the background and circumstances under which the legistration was enacted and the details of this act were investigated and analyzed. Results: In enacting Corporate Manslaughter and Corporate Homicide Act 2007, legislators mainly took elements of legal culture into account and focused on seeking to broaden the law on corporate manslaughter. An indictable offence is considered to have been committed if the way in which an organization's activities are managed or organised causes a person's death and amounts to a gross breach of the relevant duty of care owed by the organization to the deceased. The way in which its activities are managed or organized by its senior management is a substantial element in the breach. Upon conviction, a corporation may be ordered to remedy any breach, publicize its failures, or be given an unlimited fine. Conclusions: The enactment background and details of Corporate Manslaughter and Corporate Homicide Act 2007 is understood accurately. On the basis of the findings, it is necessary to heighten effectiveness of punishment.for senior management or corporations that cause a person's death in Korea.

• 전력전자학회논문지
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• 제13권3호
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• pp.221-228
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• 2008

본 논문에서는 BLDC MOTOR를 2상 여자 unipolar PWM방식으로 구동할 때 개방된 상의 역병렬 다이오드를 통해 원치 않는 누설전류의 흐름이 생기는 원인 및 영향을 분석하고 이를 제거할 수 있는 개선된 unipolar PWM 방식을 제안하였다. 개방된 상에 흐르는 누설전류는 속도가 증가할수록, PWM duty가 감소할수록 증가하며 전동기 출력의 손실을 초래한다. 제안된 unipolar PWM방식의 유효성을 시뮬레이션 및 실험을 통하여 검증하였다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제49권12호
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• pp.813-820
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• 2000

A technique to suppress the low frequency ripple voltage of the DC output in three phase buck diode converter is presented in this paper. The proposed pulse frequency modulation methods and duty ratio modulation methods are employed to regulate the output voltage of the buck diode converter and guarantee zero-current-switching(ZCS) of the switch over the wide load range. The proposed control methods used in this paper provide generally good performance such as low THD of the input line current and unity power factor. In addition, control methods can be effectively used to suppress the low frequency ripple voltage appeared in the dc output voltage. The harmonic injection technique illustrates its validity and effectiveness through the simulations and experiments.

• Journal of Power Electronics
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• 제6권2호
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• pp.95-103
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• 2006

In this paper, a novel prototype of auxiliary switched capacitor assisted voltage source soft switching PWM Single-Ended Push Pull (SEPP) series capacitor compensated load resonant inverter with two auxiliary edge resonant lossless inductor snubbers is proposed and discussed for small scale consumer high-frequency induction heating (IH) appliances. The operation principle of this inverter is described by using switching mode equivalent circuits. The newly developed multi resonant high-frequency inverter using trench gate IGBTs can regulate its output AC power via constant frequency edge-resonant associated soft switching commutation by using an asymmetrical PWM control or duty cycle control scheme. The brand-new consumer IH products which use the newly proposed edge-resonant soft switching PWM-SEPP type series load resonant high-frequency inverters are evaluated using power regulation characteristics, actual efficiency vs. duty cycle and input power vs. actual efficiency characteristics. Their operating performance compared with some conventional soft switching high-frequency inverters for IH appliances is discussed on the basis of simulation and experimental results. The practical effectiveness of the newly proposed soft switching PWM SEPP series load resonant inverter is verified from an application point of view as being suitable for consumer high-frequency IH appliances.