• 조명전기설비학회논문지
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• 제29권5호
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• pp.65-70
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• 2015

Lightning is one of hazards affecting the rapid-transit railway system. There are two effects, which are direct lightning surge to electric car line and induced lightning surge. Protection methods for the direct lightning surge are studied with various occasions, however, study of induced lightning surge is insufficient in spite of a large or small effects. In this paper, it is analysed the way that serge voltage is induced to electric car line by lightning strikes. By modeling the propagation process and the coupling phenomenon of electromagnetic wave produced by lightning strikes, it is achieved to make integrative circuit model combined with existing electric car model. The study is conducted into three different waveform of electromagnetic wave produced by lightning; rectangular wave, double exponential distribution wave, triangle wave. It is also simulated that the inducing serge is coupled to electric car line in an arbitrary location. The simulation results in that, when rapidly changing rectangular wave is supplied, maximum power is induced to electric car line.

• 한국철도학회논문집
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• 제6권4호
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• pp.246-251
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• 2003

A quantitative analysis on the amounts of cant and lateral displacement of gravitational center due to the introduction of high-speed tilting car was carried out, based on the current alignment of the conventional line. In addition, the maximum allowable speed in curve and the level of improvement in maximum speed of tilting car were evaluated through the comparison with the maximum speed of locomotive. It was found that the tilting car produces an equivalent amount of cant, which corresponds to 47.5 % of current actual cant. This effect could be explained by the fact that 1.34 m, which is the height of gravitational center of tilting car from the rail level, is much lower than that of locomotive and thus guarantees much higher level of safety in curve. The equivalent amount of cant due to the lateral displacement of gravitational center followed by tilting in curve was 2.4 mm. It was small but not enough to be neglected and must be included in calculating the maximum speed in curve. It could be concluded that the 15 % speed-up of the conventional line is reasonable under the current condition of alignment.

• 제어로봇시스템학회논문지
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• 제6권2호
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• pp.146-154
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• 2000

An $H\infty$ controller is designed for active suspensions of vehicles using 7-degree-of-freedom full-car model. Its performance robustness as well as stability robustness to system parameter variations and unmodelled dynamics are assured through the $\mu$-framework. The performance of the $H\infty$ controller is compared with that of a LQC controller in compute simulations. From the simulations it is found that the active suspension with the $H\infty$ controller reduces the acceleration and motion of the sprung mass in the heaving rolling and pitching directions when the car is driven on a normal road or through an asymmetric bump. The suspension stroke and the road holding capability are also improved with a relatively small level of power consumption. Overall the $H\infty$ controller shows a more robust performance than that of the LQG design.

• 로봇학회논문지
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• 제5권1호
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• pp.55-63
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• 2010

This paper describes performance improvement of GPS/DR Integration system using area decision algorithm and vehicle movement information. In GPS signal blockage area, i.e., tunnel and underground parking area, DR sensor errors are accumulated and navigation solution is gradually diverged. We use the car movement information according to moving area to correct the DR sensor error. Also, vehicle movement is decided as stop, straight line, turn and movement changing region through DR sensor data analysis. The car experiment is performed to verify the supposed method. The results show that supposed method provides small position and heading error than previous method.

• 오토저널
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• 제5권2호
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• pp.56-63
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• 1983

The aerodynamic characteristics of the most popular car (PONY 2) produced in Korea have been experimentally investigated by Seoul National University's wind tunnel. The model (PONY 2) chosen for the wind tunnel was a 1/5 scale of the original car without simulated underbody, cooling air flow and accessories. The measured aerodynamic drag coefficient corrected by JARI formula is 0.45 which is very close to those of small foreign cars. To see the effect of the different configurations on the aerodynamic drag, the modifications have been made by changing the hood slope and backlight slope, and putting the add-on-aerodynamic devices on the orignal shape. The rear spoiler was found the most effective one to reduce the aerodynamic drag. It may be concluded that the considerable aerodynamic drag reduction can be achieved by changing the slopes and A-O-A devices at the proper places of the car.

• 오토저널
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• 제5권2호
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• pp.15-20
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• 1983

The nature and the sources of sound in cars is discussed in the light of many previous works, and the importance of the system resonances inside cars is suggested. An investigation of a 'boom' problem in a small size passenger car is described. It was established that the 'boom' frequencies coincided with engine firing frequency and also with several system resonances. To find out main transmission path of the noise to the car interior, various possible sources were eliminated from the investigation by means of simple modification to the vehicle. Data on the structural modes of the body, and the acoustic modes of the passenger compartment at various forcing cases were obtained to provide better understanding of the problem. It was found that the acoustic resonance responsible for the boom was controlled largely the bending motion of the floor. To investigate the effect of the structural modification to the acoustic response, center floor of the car was reinforced. a great reduction of the noise inside the car especially at the offending speed range, was achieved by this modification.

• 한방재활의학과학회지
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• 제24권1호
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• pp.65-76
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• 2014

Objectives The purpose of this study is to investigate the corelation between traffic accident severity and treatment period and cost by traffic accident. Methods Outpatients who visited Jaseng Korean medicine hospital traffic accident clinic were investigated by hospital computer system about period and cost of treatment. And we requested for repair cost of car, a sort of car groups and agreement date with car insurance company to insurance company. Therefore we could analysis statistical correlation of traffic accident severity (repair cost of car) with period of treatment, cost of treatment, number of treatment in same sort of car groups. For statistics, we used SPSS version 18.0 for windows. Results A significant positive correlation was found between traffic accident severity (repair cost of car) with repair cost of car, cost of treatment and number of treatment in semi-midsize car, midsize car group. But, any significant correlation wasn't found between traffic accident severity (repair cost of car) with repair cost of car, cost of treatment and number of treatment in small car, full-sized car group. In SUV (sport utility vehicle) car group some significant correlation was found, but it isn't between traffic accident severity (repair cost of car) with repair cost of car, cost of treatment and number of treatment. Conclusions It was found that traffic accident severity (repair cost of car) had an effect on cost of car, cost of treatment and number of treatment by statistical analysis. But, it was also suggested strongly that other factors like a cost of car and ages had an effect on them.

• 한국융합학회논문지
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• 제12권2호
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• pp.173-177
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• 2021

본 연구에서는 경차와 대형차의 중공축을 가진 스테빌라이저 모델들의 비틀림 강성과 내구성을 해석하여 서로 비교 및 검토하였다. Model 1이 가해진 모우멘트가 Model 2에 비하여 3배 이상이었지만 최대변형량은 2.6배 정도로 크게 나타났다. Model 1, Model 2 공히, 스테빌라이저 바 링크 목 부분에서 가장 많은 응력을 받는 것으로 보인다. 또한 Model 1의 최대응력은 Model 2보다 2.9배 정도로 크게 나타났다. 대형차에서의 Model 1이 소형차에서의 Model 2 보다 약 20배 이상의 변형 에너지를 보였다. 전반적으로 스테빌라이저의 변형 에너지보다 스테빌라이저 바를 고정해주는 모멘트를 가한 쪽의 브라켓 부분의 값이 큰 것을 확인할 수 있었다. 그리고 본 연구에서의 해석 결과들은 경차나 대형차에서의 스테빌라이저의 내구성이 있는 부품으로서 그 융합연구 설계에 도움이 될 수 있다고 사료된다.

• 환경정책연구
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• 제14권4호
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• pp.23-44
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• 2015

저탄소차협력금제도는 중대형차 위주의 국내 승용차 시장에서 소형차의 점유율을 제고하고 온실가스를 저감하기 위해 도입되었으며 2015년 시행이 예정되어 있었으나 2014년 산업부 등이 해당 제도의 온실가스 저감효과가 낮고 수입차에 상대적 혜택이 있다고 주장하였고, 관련자들의 토론을 거쳐 제도의 시행이 2020년으로 연기되었다. 2014년 집중되었던 기존의 연구는 실증분석 위주로 제도의 효과를 추정하는 데 집중되어 있었으며, 정량적 수치를 제공하지 못하는 경제모형에 입각한 구조적 논의는 별로 주목받지 못하였다. 자동차 시장 구조에 따라 보너스-부담금이 자동차 가격에 반영되는 효과가 달라질 수 있음을 경제수리모형을 통해 입증하였고 제도를 둘러싼 구조에 대한 정밀한 통찰을 제공하여 정합한 실증분석을 위한 이론적 기반을 제시하고자 한다. 자동차 공급자가 독점력을 가지고 있어 전략적 가격 설정이 가능하다면 보너스와 부담금이 자동차 가격에 반영되는 정도는 명목적으로 부여된 수준보다 작다. 보너스가 부과되는 소형차 시장만 독점력이 떨어지더라도 제도의 효과가 개선된다. 최적의 보너스와 부담금이 도입되어 있다고 가정했을 때 자동차 시장 구조가 변화한다면 최적 가격 체계를 유지하기 위한 보너스와 부담금 변화 방향은 직관과 다를 수 있다. 각 시장의 가격탄력성과 대체탄력성의 크기가 최적 보너스-부담금의 변화 방향을 결정한다. 예를 들어 대형차 수요는 탄력적이고 소형차 수요가 비탄력적이면서 대체탄력성은 낮은 경우 독점력이 강화된다면 보너스와 부담금 모두 상향 조정되어야 한다.

• 한국산학기술학회논문지
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• 제11권1호
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• pp.257-263
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• 2010

1998년 12월에 개정된 상법에서, 경제위기를 극복하기 위한 정책수단의 일환으로 기업 구조조정 및 M&A활성화를 도모하기 위하여 기업분할제도가 도입된 이후 한국 기업들의 기업분할이 시작되어 오늘에 이르고 있다. 한국기업의 기업분할의 목적은 대부분 사업부문의 전문화와 경영효율화를 위하여 실시되고 있으며 M&A와 마찬가지로 기업분할은 이제 기업경영에 있어서 구조조정의 중요한 도구의 하나로 이용되고 있다. 본 연구는 기업분할시 소유구조와 기업규모에 따른 공시효과의 차이를 검증하기 위하여 1999년부터 2005년까지 기업분할 공시를 한 기업을 대상으로 기업규모와 최대주주지분의 분포별로 누적초과수익률을 조사하여 분석하였다. 또한 기업의 공시효과와 소유구조와의 관련성을 분석하기 위하여 소유지분변수를 이용하여 회귀분석을 실시하였다. 연구결과를 살펴보면 다음과 같다. 최대주주지분율이 일정한 값을 초과하게 된다면 기업의 분할성과를 하락시키는 요인으로써 작용할 수 있다고 볼 수 있다. 또한 기업규모에 따른 분할성과를 살펴본 결과 기업규모에 상관없이 대체적으로 양(+) 초과수익률을 보이고 있으나 기업규모가 작은 기업이 기업규모가 큰 기업보다 상대적으로 변동성이 큰 것을 알 수 있다. 마지막으로 기업소유구조가 분할 공시효과와의 횡단면적 차이를 설명할 수 있는지를 분석하기 위하여 소유구조 변수와 CAR의 회귀분석을 실시한 결과 최대주주지분율과 외국인투자자지분율에서 유의한 통계량 값을 발견하였다.