• 한국자동차공학회논문집
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• 제22권1호
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• pp.174-182
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• 2014

Recently, not only common types of hybrid electric vehicle (HEV) such as series or parallel but many other types of HEVs including 4WD hybrid electric vehicle have been developed and released. In this study, analysis of fuel economy and driving performance for 2WD and 4WD HEV are conducted using backward simulation based on dynamic programming. To analyze the characteristics of 4WD HEV, tire slip model based on vehicle dynamics was applied to the backward simulation program. As a result, 2WD HEV shows better fuel economy than 4WD HEV because of relatively simple configuration. However, in a severe road condition, 4WD HEV shows better driving performance that 2WD HEV had about 6% of impossible time to follow the driving cycle though the 4WD HEV had no impossible time.

• 한국광학회:학술대회논문집
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• 한국광학회 2002년도 하계학술발표회
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• pp.230-231
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• 2002

Recently, analysis of transient Raman backscattering in a plasma reported(2.3) that it is possible to reach 10$\^$17/ W/cm$^2$ for 1 micrometer wavelength laser pulse with a counter-propagating pump pulse. The basic mechanism is like this ： whorl the two counter-propagating waves in a plasma satisfy the condition of Raman backscattering, w$\_$0/ ： w$\_$1/ ＋ w$\_$p/, energy is transferred from the long pulse to the short pulse via three wave interaction(4). (omitted)

• 대한치과교정학회지
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• 제32권3호
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• pp.155-163
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• 2002

치조성 양악 전돌 증례에서 컴퓨터 시뮬레이션을 이용한 연조직 측모의 치료 결과 예측의 객관적 정확성을 상, 하악 제 1소구치 발거를 통해 교정치료를 받은 21명의 성인 여성을 대상으로 $Quick\;Ceph\;Image\;Pro^{TM}\;&\;Quick Eeph\;2000^{TM}$ 을 이용하여 조사, 평가하였다. 치료 전 측모 두부방사선 규격사진 투사도에서 경조직 이동량을 계측하고 Quick Ceph system 상에서 경조직을 동일한 양 이동시켜 컴퓨터시뮬레이 션을 위한 기준으로 삼았다. 이후 프로그램을 통해 연조직 변화를 시뮬레이션하고, 이 자료와 실제 치료 결과로 얻어진 연조직 계측 값을 측정하여 비교해 봄으로써 치료 결과 예측에 대한 정확도를 확인하고 임상에의 적용시 고려할 사항을 알아보았다. 시뮬레이션 결과 계측 항목의 수평 성분은 실제 치료 결과보다 작게, 수직 성분은 치료 결과보다 크게 예측하는 것으로 나타났으며 치료시 의 후방 견인은 실제보다 확대되어 나타나는 경 향을 보였다. 상악에서는 항목간 예측 오차의 방향이 일정하여 예측치가 실제보다 더 후방 이동되어 나타났으나, 하악에서는 증례간 차이가 컸다 Upper Lip Length는 짧게, Upper Vermilion Length는 길게 예측하여 시뮬레이션시 상순이 말려 보이는(rolling)효과를 확인할 수 있었으며 하순에서도 유사한 성향이 나타났으나 상순에 비해서 약하게 나타났다.

• 한국자동차공학회논문집
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• 제24권3호
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• pp.330-337
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• 2016

In this paper, component sizing and analysis of the novel plug-in hybrid electric vehicle powertrain configuration is conducted. Newly proposed powertrain configuration in prior study has an internal combustion engine and two electric motors. To optimize component size of the vehicle system and reduction gear ratio, component sizing methodology is proposed and conducted. Required power for vehicle's dynamic performance is calculated to decide minimum power requirement of powertrain component combination. Component size of engine and electric motor are optimized using vehicle simulation to maximize fuel economy performance. Optimized powertrain configuration and vehicle simulation results present validation of newly proposed vehicle system.

• 한국자동차공학회논문집
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• 제23권4호
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• pp.436-443
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• 2015

In order to develop the PHEV(plug-in hybrid electric vehicle), the specific power transmission systems considering the PHEV system characteristics should be applied. A PHEV applied to series-parallel type hybrid power transmission system is a typical example. In this paper, the novel hybrid power systems are proposed by analyzing the existing PHEV system. The backward simulation program is developed to analyze the fuel efficiency of hybrid power system. Quasi-static models for each components such as engine, motor, battery and vehicle are included in the developed simulation program. To obtain an optimal condition for hybrid systems, an optimization approach called the dynamic programming is applied. The simulation is performed in various driving cycles. A weakness for the existing system is found through the simulation. To compensate for a discovered weakness, novel hybrid power systems are proposed by adding or moving the clutch to the existing system. Comparing the simulation results for each systems, the improved fuel efficiency for proposed systems are verified.

• 한국자동차공학회논문집
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• 제21권1호
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• pp.92-98
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• 2013

There are lots of studies about hybrid electric vehicles (HEVs) because of the global warming and energy problems. Series and parallel HEVs are the common types of many developing hybrid vehicle types. Series HEV uses engine only as the generator for the battery but parallel HEV utilizes engine for driving and generating of the vehicle. In this paper, backward simulations based on dynamic programming were conducted for the fuel economy analysis of two different types of hybrid transit buses depending on driving cycles. It is shown that there is a relation between the type of HEV and the characteristics of driving cycles. Regarding the aggressiveness, the series hybrid bus is more efficient than the parallel system on highly aggressive driving cycle. On the other hand, the parallel hybrid bus is more efficient than the series system on low aggressive driving cycle. Based on this results of the paper, it is expected to choose more efficient type of the hybrid buses according to the driving cycle.