• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(2)
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• pp.755-760
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• 2003

A novel current-fed energy-recovery sustaining driver (CFERSD) for a PDP is proposed in this paper. Its main idea is to recover the energy stored in the PDP or to inject the input source energy to the PDP by using the current source built-up in the energy recovery inductor. This method provides zero-voltage-switching (ZVS) of all main power switches, the reduction of EMI, and more improved operational voltage margins with the aid of the discharge current compensation. In addition, since the current flowing through the energy recovery inductor can compensate the plasma discharge current flowing through the conducting power switches, the current stress through all main power switches can be considerably reduced. Furthermore, it features a low conduction loss and fast transient time. Operations, features and design considerations are presented and verified experimentally on a 1020X106mm sized PDP, 50kHz-switching frequency, and sustaining voltage 140V based prototype.

• 아태비즈니스연구
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• 제14권3호
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• pp.221-240
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• 2023

Purpose - This paper investigates how business cycle impacts on corporate credit spreads since global financial crisis. Furthermore, it tests how the impact changes by the phase of the cycle. Design/methodology/approach - This study collected dataset from Barclays Global Aggregate Bond Index through the Bloomberg. It conducted multi-regression analysis by projecting business cycle using Hodrick-Prescott filtering and various cyclical variables, while ran dynamic analysis of 5-variable Vector Error Correction Model to confirm the robustness of the test. Findings - First, it proves to be statistically significant that corporate credit spreads have moved countercyclicaly since the crisis. Second, It indicates that the corporate credit spread's countercyclicality to the macroeconomic changes works symmetrically by the phase of the cycle. Third, the VECM supports that business cycle's impact on the spreads maintains more sustainably than other explanatory variable does in the model. Research implications or Originality - It becomes more appealing to accurately measure the real economic impact on corporate credit spreads as the interaction between credit and business cycle deepens. The economic impact on the spreads works symmetrically by boom and bust, which implies that the market stress could impact as another negative driver during the bust. Finally, the business cycle's sustainable impact on the spreads supports the fact that the economic recovery is the key driver for the resilience of credit cycle.

• 산업경영시스템학회지
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• 제32권1호
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• pp.26-33
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• 2009

The directions of the road are divided into two, the right-hand side and left-hand side of the road, by the convention and specific native method in the world. This paper deals with the characteristics and behaviors of drivers who are accustomed to driving on right-hand side of the road, drive with a handle on the left-hand side, and comparing with left-hand side drivers. The driver's eye movements were measured by eye camera and questionnaires were used for measuring subjective evaluation such as driving mental workload. The experimental results indicated even if the experts who had much experience on right-hand side driving, they had lower driving skill than novice driver, accustomed to driving on left-hand side. In terms of mental workload, MCH rating scale and MNASA-TLX, the right-hand side drivers were in lower stress condition than the left-hand side drivers because of having much driving experience. However, they conducted a few mistakes by confusing the position of turn signal and windshield wiper because of their driving habit or traits and it lead to operation mistakes. These results can be applied effectively to develop the driving support information with changed environments.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2011년도 춘계학술대회
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• pp.481-484
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• 2011

최근의 자동차 기술이 기계적 장치 위주에서 전장부품 특히, 차량의 안전 및 편의 기술로서 발전되고 있어서, 추후 자동차의 경쟁력은 에너지 효율성문제와 안전편의 기술의 적용에 의해 그 경쟁력이 결정될 것으로 판단된다. 본 연구에서는 자동차 운전자 졸림의 검지하기 위한 각종 기술을 소개하고 상용화된 기술의 장단점을 비교하여서, 이의 문제점을 해결하기 위한 복합 센싱기술을 소개한다. 기존의 카메라에 의한 눈동자인식을 기반으로한 직접적인 졸림검지와 운전자의 생체신호를 검출하여 간접적으로 스트레스, 피로도, 졸림을 검출하는 방법을 결합하여, 보다 정확도가 높은 졸림검지가 가능한 알고리즘을 개발하였다.

• 한국기계가공학회지
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• 제17권3호
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• pp.28-33
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• 2018

The automotive front bumper guard is the most important part of the vehicle for protecting the life of driver when a traffic accident happens. In order to ensure safe driving, this part must possess sufficient strength and durability. This study was carried out with structural and fatigue analyses by designing front bumper guard models. After the lowest value for maximum total deformation and equivalent stress was found through structural analysis and the highest value for fatigue life was found for all three models, it was shown that the type C front bumper guard model was the most suitable for application to a real car. The strength property and durability of the optimum design were determined through this study's results.

• 한국전산유체공학회지
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• 제11권2호
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• pp.25-31
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• 2006

A two-dimensional backward facing step flow is simulated by using URANS and Detached Eddy Simulations(DES) approaches. Turbulence models adopted for URANS and DES simulations are Spalart-Allmaras(S-A) model and Shear Stress Transport(SST) model. The target flow with ER=1.125, $Re_H=37,500$ is experimentally studied by Driver & Seegmiller. Various versions of DES have been tested in this paper. Results of the simulations are compared with the experimental data available to evaluate the merits and demerits of URANS and several versions of DES. URANS simulation converges to a steady state and hence unsteady characteristics are not featured. DES simulations in general successfully mimic large scale structures and oscillation characteristics of the flow.

• 대한안전경영과학회지
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• 제15권4호
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• pp.113-121
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• 2013

The rate that women's EMTs(emergency medical technicians) in fire department occupy is increasing, but my general plan is aimed at suggesting the improving plan for the working environment of women's EMTs paying attention to the duty stresses of increasing women's EMTs, because improvement for the working environment of women's EMTs is being proceeded slowly. I suggested my improving plan for solving the working stress on the basis of a survey of the Recognition against women's EMTs as follows. Firstly, I suggested that physical strength of women's EMTs should be managed well continually via program establishment and a defined evaluation not only by employing a professional person in charge for physical strength in firehouse, but also by replenishing the suitable number for the urgent mobilization. Secondly, I suggested that the suitable number for the urgent mobilization should be increased to 3 including an ambulance driver. Thirdly, I suggested necessity such as the fruitful education and the creation of circumstances that can focus on education for improving participation rate, development of various new educational program, incentive program and penalty. finally, I suggested the fact that is related to the actual re-amendment of the concerned law and ordinance such as not only the smooth treatment of penalty for a traffic signal violation of ambulance and the legal remedy system due to aggravation of a patient's condition during a first-aid course, but also workshop and meeting among the periodical EMTs and administration of special therapy program and sufficient recess.

• 한국직업건강간호학회지
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• 제24권4호
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• pp.363-371
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• 2015

Purpose: The purpose of this study was to investigate the factors influencing health promoting lifestyle of urban bus driver in small-sized companies. Methods: This study included 118 urban bus drivers who completed questionnaires. The data were collected from 6 small-sized bus companies located in a metropolitan city, from January to February 2015. Analyses were done using descriptive statistics, independent t-test, ANOVA, Pearson's correlation, and multiple regression analysis. SPSS/Win 18.0 was used. Results: The scores of HPLP of urban bus drivers were 2.7 (on a 4-point scale). Mean of HPLP sub-scores were self-fulfillment ($3.0{\pm}0.5$), interpersonal relationship ($2.9{\pm}0.5$), physical activity ($2.9{\pm}0.7$), health responsibility ($2.7{\pm}0.5$), healthy diet ($2.6{\pm}0.6$), and stress management ($2.5{\pm}0.5$). Among independent variables, job satisfaction and presence of religion were significantly related to health promoting lifestyle (explained 39.2%). Conclusions: This study revealed that there is a need to strengthen job satisfaction for urban bus drivers' health promoting lifestyle.

• 조명전기설비학회논문지
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• 제21권9호
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• pp.1-6
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• 2007

In this study, tests of brain waves were carried out to investigate the physiological characteristics of drivers during a change of headlight brightness. The participants were 20 males in their 20s. Twenty-three different conditions combining the waveform of light, voltage, and alteration time were used. The measurement of brain waves was performed by an internationally standardized 10-20 method using LXE3232-RF. The results were as follows. 1. From the results of the brain wave map analysis, it was suggested that waveform A increases mental stress and waveform B affects mental and visual stress. The longer the stimulation time, the more stress level was detected. 2. The voltage alteration time of the B waveform should be kept to less than 1500msec, while the voltage should not fall below 11.5[V].

• 한국ITS학회 논문지
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• 제9권3호
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• pp.20-29
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• 2010

가변전광표지판(VMS)은 교통정보제공 서비스 매체중 가장 이용자가 많고, 정부기관에서 제공 운영하고 있는 대표적인 매체라고 할 수 있다. 그리하여 VMS는 이용자 중심의 서비스를 제공할 필요성이 있으므로 VMS 교통정보 이용자의 심리적 반응에 관한 연구를 수행하였다. 총 3가지 시나리오를 구성하여 주행실험을 실시하였다. 첫 번째 시나리오인 VMS설치위치에 관한 스트레스 지수분석 결과 출구 1.5km전 일때 가장스트레스가 적게 나타났다. 이는 국토해양부 VMS운영지침에서 도시부 고속도로의 경우 VMS정보는 출구 1~2km전에 제공해야 한다는 항목과 일치하는 결과를 나타내며 이용자의 심리상태를 고려하여 보다 더 정확한 제공거리를 산출한 것이라 할 수 있다. 두 번째 시나리오인 VMS정보제공 내용(소통정보, 시간정보, 속도정보)에 관한 스트레스 지수분석결과 시간정보가 가장 스트레스가 적게 나타났다. 제공한 정보 내용이 비교적 장거리(가양${\rightarrow}$천호 약 28km)이라는 점을 감안할 때 속도나 소통에 대한 정보는 운전자들이 경로선택을 위해 고민을 해야 하지만 시간정보는 걸리는 시간을 바로 알 수 있으므로 유용하다고 할 수 있다. 본 연구를 통해 운전자들의 심리적 반응측면에서 출구 1.5km전에는 정보를 주는 것이 좋고, 시간정보를 다른 정보내용보다 쉽게 받아들이는 것을 알 수 있다.