• 대한전자공학회논문지TC
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• 제47권6호
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• pp.35-41
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• 2010

u-TSN (ubiquitous-transportation sensor network) 시스템은 차량에서의 주기적인 정보를 노변장치가 수집하고 수집된 정보의 분석, 가공하여 교통정보를 제공하는 차세대교통시스템이다. 본 논문에서는 u-TSN 시스템에서의 교통정보 수집을 위한 차량에서의 메시지 전송방안을 제안한다. 기존의 시스템은 0.1초마다 차량 정보를 전송하는 것으로 되어 있다. 본 논문에서는 차량 속도에 따라 차량위치 정보의 전송 주기를 조절하는 알고리듬을 제안한다. 제안 전송방법의 우수성을 컴퓨터 모의실험을 통해 기존 방식과 비교 한다.

• 전력전자학회논문지
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• 제27권1호
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• pp.1-8
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• 2022

Recently, photovoltaic (PV) systems have been gradually applied in eco-friendly vehicle applications to improve fuel economy. The relevant market is expected to continue to grow because the installation of large-capacity PV systems to other eco-friendly vehicles, such as electric buses and trains, is being considered. However, in a PV system, power imbalance between submodules and low power generation efficiency occur due to factors such as cell aging, contamination, and shading. To resolve this problem, various differential power processing (DPP) converters have been researched and developed. However, conventional DPP converters suffer from large volume and low efficiency. Therefore, to apply DPP converters to eco-friendly vehicles, increasing efficiency and reducing volume and price compared with existing DPP converters is necessary. In this paper, a novel DPP converter with an integrated transformer is proposed and analyzed. The proposed DPP converter uses a single magnetic component by integrating transformers and secondary sides of conventional DPP converters. Therefore, the proposed DPP converter shows high power density and high efficiency, and it is suitable for PV systems in eco-friendly vehicle applications.

• 한국해양공학회지
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• 제18권4호
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• pp.33-39
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• 2004

This paper presents a hybrid underwater navigation system for unmanned underwater vehicles, using an additional range sonar, where the navigation system is based on inertial and Doppler velocity sensors. Conventional underwater navigation systems are generally based on an inertial measurement unit (IMU) and a Doppler velocity log (DVL), accompanying a magnetic compass and a depth sensor. Although the conventional navigation systems update the bias errors of inertial sensors and the scale effects of DVL, the estimated position slowly drifts as time passes. This paper proposes a measurement model that uses the range sonar to improve the performance of the IMU-DVL navigation system, for extended operation of underwater vehicles. The proposed navigation model includes the bias errors of IMU, the scale effects of VL, and the bias error of the range sonar. An extended Kalman filter was adopted to propagate the error covariance, to update the measurement errors, and to correct the state equation, when the external measurements are available. To illustrate the effectiveness of the hybrid navigation system, simulations were conducted with the 6-d.o.f. equations of motion of an AUV in lawn-mowing survey mode.

• 한국분무공학회지
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• 제23권4호
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• pp.212-220
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• 2018

As increase the number of vehicles, the issue of greenhouse gas that was emitted by them became important. As a result, greenhouse gas (GHG) regulations are being strengthened and efforts are being actively made to reduce greenhouse gas emissions in the automotive industry. In the other hand, regulations for harmful emission of vehicles have been reinforced by step. Especially, the lastly applied step, so called Euro 6, not only decreased NOx limit down to half of Euro 5 but also introduced real driving emission limit for NOx and PN. It is a challenge for manufacturers to meet the recent GHG regulation as well as the latest emission regulation. To overcome these regulations a De-NOx after-treatment system is being applied to diesel vehicles that are known emitting the lowest GHG among conventional internal combustion engines. At the time of the introduction of Euro 6 emission standard in Korea, in the domestic fuel economy certification test, some diesel vehicles emitted more $CH_4$ than Euro 5 vehicles. As a result, it was confirmed that LNT-equipped vehicles emitted a high level $CH_4$ and the level exceeded the US emission standard. In order to determine the reason, various prior literature was investigated. However, it was difficult to find a detailed study on the methane increase with LNT. In this paper, to determine whether the characteristics of vehicles equipped with LNT the affects the above issue and other greenhouse gases, 6 passenger cars were tested on several emission test modes and ambient temperatures with a environment chamber chassis dynamometer. 2 cars of these were equipped with LNT only, other 2 cars had SCR only, and LNT + SCR were applied to remaining 2 cars. The test result shown that the vehicles equipped with LNT emitted more $CH_4$ than the vehicles with SCR only. Also, $CH_4$ tended to increase as the higher acceleration of the test mode. However, as the test temperature decreases, $CH_4$ tended to decreased. $CO_2$ was not affected by kinds of De-NOx device but characteristic of the test modes.

• 에너지공학
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• 제19권2호
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• pp.92-102
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• 2010

플러그인 하이브리드 전기자동차(Plug-in Hybrid Electric Vehicle, PHEV)는 하이브리드 전기자동차(Hybrid Electric Vehicle, HEV)의 일종으로, 배터리 용량을 HEV보다 더욱 증대시키고 배터리의 충전을 전력망으로부터 할 수 있도록 한 자동차이며, 순수 배터리 전기자동차(Plug-in Battery Electric Vehicle, PBEV)는 전력망으로부터 전기를 배터리에 충전하여 저장하고 배터리에 저장된 전기만을 이용하여 운전가능한 자동차이다. 최근에 PHEV와 PBEV에 대한 관심과 개발이 전세계적으로 급속하게 증가하고 있다. 그러므로 이들 전력망 충전식 전기자동차가 전력망의 전력수요에 미치는 영향을 검토하는 것이 중요하다. 본 논문에서는 이들 PHEV와 PBEV 자동차의 보급으로 전력망의 전력수요, 이산화탄소 배출량과 차량구매자의 관점에서 운전비용에 미치는 영향을 분석하였다. 2020년경에 차량보급이 10%정도로 이루어질 것을 가정하여 영향을 분석하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권10호
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• pp.3955-3971
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• 2020

Due to the significant increase in the use of autonomous car technology, it is essential to integrate this technology with high-precision digital map data containing more precise and accurate roadway information, as compared to existing conventional map resources, to ensure the safety of self-driving operations. While existing map technologies may assist vehicles in identifying their locations via Global Positioning System, it is however difficult to update the environmental changes of roadways in these maps. Roadway vision algorithms can be useful for building autonomous vehicles that can avoid accidents and detect real-time location changes. We incorporate a hybrid architectural design that combines unsupervised classification of vision data with supervised joint fusion classification to achieve a better noise-resistant algorithm. We identify, via a deep learning approach, an intelligent hybrid fusion algorithm for fusing multimodal vision feature data for roadway classifications and characterize its improvement in accuracy over unsupervised identifications using image processing and supervised vision classifiers. We analyzed over 93,000 vision frame data collected from a test vehicle in real roadways. The performance indicators of the proposed hybrid fusion algorithm are successfully evaluated for the generation of roadway digital maps for autonomous vehicles, with a recall of 0.94, precision of 0.96, and accuracy of 0.92.

• 한국콘텐츠학회논문지
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• 제19권12호
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• pp.452-459
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• 2019

자율주행자동차를 상용화하기 위해서는 모든 측면에서 안전성 테스트를 수행해야 한다. 자율주행자동차 기술의 구현을 고려할 때, 시내상황과 같은 복잡한 환경에서 발생할 수 있는 시나리오를 분석 할 필요가 있다. 자율 주행 차량이 기존의 교통 환경에서 정상적인 작동이 가능한지 여부의 평가도 중요하다. 또한 자율주행 자동차가 일반 차량과의 상호 작용을 검토하고, 도로에서 발생할 수 있는 사고에 대처할 필요가 있다. 본 연구는 도로환경에서 자율주행자동차의 평가 요소들을 기존의 ADAS와 같은 평가 프로토콜을 참고하여 자율주행 차량의 평가 방안을 모색하였다. 연구 결과는 다양한 기술 구현수준과 함께 다른 시험환경에 대한 자율 차량평가 방법을 수립하는데 반영하고자 한다.

• 한국컴퓨터정보학회논문지
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• 제15권7호
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• pp.41-47
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• 2010

고속도로에서 발생하는 차량간의 응급상황은 사람과 차량의 안전을 위해 후방 차량들에게 신속하게 전달되어야 한다. 지금까지 차량간 메시지 전송은 802.11을 이용한 무선환경에서 브로드캐스트 방식으로 전달되어 왔다. 이는 메시지를 수신을 할 필요가 없는 차량에 까지 메시지를 전송하여 메시지 충돌과 무선 네트워크의 대역폭을 낭비한다. 메시지 충돌은 최후방 차량의 메시지 수신 시간이 오래 걸리는 요인이 된다. 본 논문은 기존의 문제를 극복하고자 차량을 셀(cell) 단위로 그룹화하고 셀 대표(CP: Cell Primary) 차량이 멤버 차량에게 메시지를 브로드캐스트하는 셀기반의 응급 메시지 브로드캐스트 기법(Message Broadcast based on Cell, MBC)을 제안한다. 실험에서는 제안 기법이 동일 환경의 브로드캐스트 보다 후방 차량의 메시지 수신율이 향상되어 응급메시지의 전송에 뛰어난 성능을 보인다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.222-227
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• 2004

Korean High Speed Train(KHST) has been tested on the high speed test line in Osung site, since it was developed through the G7 Project Plan in 2002. It was also tested on the conventional line such as KyongBu and Honan Line to know the possibility of increasing the limited speed for the high speed trains. This paper introduces the method to improve the speed on the conventional line with body lateral acceleration among the several considered issues and explains the parameters related to those analysis, such as the cant deficiency, the radius of curve, speed and etc. When a train pass on the curved track, the lateral accelerations of body are divided into the quasi-static and the maximum accelerations according to the UIC 518 which is the international specification for testing and approval of railway vehicles from the point of view of their dynamic behaviour, especially for safety and ride comfort. This paper shows that it is safe and comfort from the results of test when KHST runs on the conventional line with the curves and proposes that the limited speed of conventional curved line could be changed to a little higher speed if the analysises of other fields are completed.

• Journal of Electrical Engineering and Technology
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• 제12권1호
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• pp.451-458
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• 2017

An Electric Vehicle (EV) is operated with the electric energy of a battery in place of conventional fossil fuels. Thus, a suitable charging infrastructure must be provided to expand the use of electric vehicles. Because the battery of an EV must be charged to operate the EV, expanding the number of EVs will have a significant influence on the power supply and demand. Therefore, to maintain the balance of power supply and demand, it is important to be able to predict the numbers of charging EVs and monitor the events that occur in the distribution system. In this paper, we predict the hourly charging rate of electric vehicles using transformation matrix, which can describe all behaviors such as resting, charging, and driving of the EVs. Simulation with transformation matrix in a specific region provides statistical results using the Monte-Carlo Method.