• 한국감성과학회:학술대회논문집
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• 한국감성과학회 2002년도 춘계학술대회 논문집
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• pp.177-180
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• 2002

The type of physiological stress involved in driving is probably complex, and a comprehensive study involving recording of physiological signals such as electrocardiogram(ECG), electromyogram(EMG). Changes in relevant Physiological parameters, such as ECG, EMG, reflected changes in driver status. In order to derive the mental and physical load of driving a motor vehicle from driving behaviour alone it is necessary to establish the relationship between changes in a driver's physiological parameters and behavioral parameters. In this study, we choose two different condition and investigated driver's status using HRV analysis method. Many previous studies have shown that increasing driving time causes a variation of HRV signal.

• 전력전자학회논문지
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• 제23권1호
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• pp.59-65
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• 2018

A new single-stage flyback power converter with PFC for electrolytic capacitor-less LED driver is proposed in this study. This method minimizes the peak-to-average ratio of the LED driving pulsating current by adding the LED driving current near the LED current valley area, as well as the third harmonic component injection into the input current. The reduced peak current value of the LED drive current minimizes the thermal stress of the LED itself, thereby increasing the reliability of the LED, as well as achieving a long lifetime. Simulation and experimental results show the usefulness of the proposed topology.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.1243-1246
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• 2009

A novel a-Si TFT integrated gate driver circuit which suppresses the threshold voltage shift due to prolonged positive gate bias to pull-down TFTs, is reported. Negative gate-to-drain bias is applied alternately to the pull-down TFTs to recover the threshold voltage shift. Consequently, the stability of the circuit has been improved considerably.

• Journal of Electrical Engineering and Technology
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• 제10권5호
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• pp.2031-2039
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• 2015

In the LED lighting industry, the dimming function in the LED lamp is required by demands of many consumers. To drive this LED lighting, various types of power converters have been applied. Among them, an LLC resonant converter could be applied for high power LED lighting because of its high efficiency and high power density, etc. The function of power factor correction (PFC) might be added to it. In this paper, a dimmable single-stage asymmetrical LLC resonant converter is proposed. The proposed converter performs both input-current harmonics reduction and PFC using the discontinuous conduction mode (DCM). Also, the lower voltage stress across switching devices as well as the zero voltage switching (ZVS) in switching devices is realized by the proposed topology. It can reduce cost and has high efficiency of the driver. In addition, the regulation of the output power by variable switching frequency can vary the brightness of a light. In the proposed converter, one of the attractive advantages doesn’t need any extra control circuits for the dimming function. To verify the performance of the proposed converter, simulation and experimental results from a 300W prototype are provided.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.122-122
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• 2010

A Static Induction Thyristor (SI-Thyristor) has a great potential as power semiconductor switch for pulsed power or high voltage applications with fast turn-on switching time and high switching stress endurance (di/dt, dV/dt). However, due to direct commutation between gate driver and SI-Thyristor, it is difficult to design optimal gate driver at the aspect of impedance matching for fast gate current driving into internal SI-Thyristor. Thus, to penetrate fast positive gate current into steady off state of the SI-Thyristor, it is proposed and proceeded the internal impedance calculation of the SI-Thyristor at steady off state with the gate driver while switching conditions that are indicated applied gate voltage, $V_{GK}$ and applied high voltage across anode and cathode, $V_{AK}$.

• 전력전자학회논문지
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• 제19권1호
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• pp.91-97
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• 2014

Recently, the LED(Light Emitting Diode) is expected to replace conventional lamps including incandescent, halogen and fluorescent lamps for some general illumination application, due to some obvious features such as high luminous efficiency, safety, long life, environment-friendly characteristics and so on. To drive the LED, a single stage PFC(Power Factor Correction) flyback converter has been adopted to satisfy the isolation, PFC and low cost. The conventional flyback LED driver has the serious disadvantage of high 120Hz output current ripple caused by the PFC operation. To overcome this drawback, a new PFC flyback with low 120Hz output current ripple is proposed in this paper. It is composed of 2 power stages, the DCM(Discontinuous Conduction Mode) flyback converter for PFC and BCM(Boundary Conduction Mode) boost converter for tightly regulated LED current. Since the link capacitor is located in the secondary side, its voltage stress is small. Moreover, since the driver is composed of 2 power stages, small output filter and link capacitor can be used. Especially, since the flyback is operated at DCM, the PFC can be automatically obtained and thus, an additional PFC IC is not necessary. Therefore, only one control IC for BCM boost converter is required. To confirm the validity of the proposed converter, theoretical analysis and experimental results from a prototype of 24W LED driver are presented.

• 대한산업공학회지
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• 제42권1호
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• pp.73-79
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• 2016

The purpose of this study is to understand human sensory and emotional response according to car noise. This study investigated human stress levels from car noise based on the data of electro-encephalogram (EEG) and subjective evaluation analysis data. Since there are few previous works on the effect of car noise on human's reaction, more profound research about the effect of car noise on driver's emotion would be worth performing. Subjects were exposed to five different kinds of car noises. EEG data were collected while the subject was exposed to noise. In order to process EEG data, FFT analysis was used to separate the collected EEG data into ${\alpha}$-wave and ${\beta}$-wave. Also, survey was performed to carry out subjective evaluation. The results of the subjective evaluation were closely correlated to those found in the EEG signal analysis. The results from this study may provide useful information for mitigating car noise induced stress.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.1023-1030
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• 2011

The purpose of this article is to find out and analyze the diverse factors that are incurring stress to the railway drivers, and to depict the relationship among personality, job stress, job satisfaction, and accidents. To attain this purpose, the authors designed the questionnaire based on in-depth interview, scrutinized the factors of stressors, and statistically tested the study themes on the moderating effects of Personality Factors such as Locus of Control, Self-Efficacy, and Organization-Based Self Esteem on the relationship between Job Stressors and Job Satisfaction/Accidents, for the 212 samples received from KORAIL, Seoul Metro, and Seoul Metropolitan Rapid Transit. Resultedly, one of the findings indicate that certain aspects of a driver's personalities, as measured by locus of control, self-efficacy, and organization-based self esteem play important roles in predicting the level of job satisfaction, job stress and accidents.

• 한국전자통신학회논문지
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• 제13권3호
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• pp.677-684
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• 2018

최근 운전 도중 운전자가 가지는 부정적인 감정 상태로 인한 문제점이 커지고 있으며 특히 우리나라 포함 교통이 혼잡한 나라에서는 교통사고뿐만 아니라 소위 '분노 운전'이라는 범죄 행위로 이어지는 사례가 잦아지고 있다. 이와 같은 상황에서 무선 통신 및 웨어러블 기술을 활용하여 스트레스나 피로로 인한 운전자의 감정 상태를 측정할 수 있다면 매우 유용할 수 있다. 본 연구는 운전자의 다양한 생체 신호를 측정 및 관찰할 수 있는 시스템을 구현하고 측정 결과 분석을 통하여 운전자의 감정 상태를 판단하고 관찰하며 예측된 운전자의 감정 상태에 대한 신뢰성을 높이기 위한 것이다. 본 논문에서는 이 연구의 전반부로서 현재 개발이 완료된 시스템 구현 과정과 실험 방법에 대해서 소개하고자 한다.

• Journal of Information Display
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• 제7권3호
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• pp.5-8
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• 2006

A novel a-Si TFT integrated gate driver circuit using multi-thread driving has been developed. The circuit consists of two independent shift registers alternating between the two modes, "wake" and "sleep". The degradation of the circuit is retarded because the bias stress is removed during the sleep mode. It has been successfully integrated in 14.1-in. XGA LCD Panel, showing enhanced stability.