• Journal of Multimedia Information System
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• 제5권2호
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• pp.105-110
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• 2018

Autonomous cars require the integration of multiple communication systems for driving safety. Many carmakers unveil mirrorless concept cars aiming to replace rear and sideview mirrors in vehicles with camera monitoring systems, which eliminate blind spots and reduce risk. This paper presents optical vehicle-to-vehicle (V2V) communications for autonomous mirrorless cars. The flicker-free light emitting diode (LED) light sources, providing illumination and data transmission simultaneously, and a high speed camera are used as transmitters and a receiver in the OCC link, respectively. The rear side vehicle transmits both future action data and vehicle type data using a headlamp or daytime running light, and the front vehicle can receive OCC data from the camera that replaces side mirrors so as not to prevent accidents while driving. Experimental results showed that action and vehicle type information were sent by LED light sources successfully to the front vehicle's camera via the OCC link and proved that OCC-based V2V communications for mirrorless cars can be a viable solution to improve driving safety.

• 제어로봇시스템학회논문지
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• 제10권8호
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• pp.703-710
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• 2004

This paper presents discontinuous zigzag gait analysis for a newly modeled quadruped walking robot with an articulated spine which connects the front and rear parts of the body. An articulated spine walking robot can move easily from side to side, which is an important feature to guarantee a larger gait stability margin than that of a conventional single rigid-body walking robot. First, we suggest a kinematic modeling of an articulated spine robot which has new parameters such as a waist-joint angle, a rotate angle of a front and rear body and describe characteristics of gait using an articulated spine. Next, we compared the difference of walking motion of newly modeled robot with that of a single rigid-body robot and analyzed the gait of an articulated spine robot using new parameters. On the basis of above result, we proposed a best walking motion with maximum stability margin. To show the effectiveness of proposed gait planning by simulation, firstly the fastest walking motion is identified based on the maximum stride, because the longer the stride, the faster the walking speed. Next, the gait stability margin variation of an articulated spine robot is compared according to the allowable waist-joint angle.

• 소성∙가공
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• 제23권6호
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• pp.357-362
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• 2014

The purpose of the current study is to predict the hardness distribution in steel products after hot stamping using a quench factor analysis(QFA) coupled with FE-simulations. QFA is a method to predict properties such as hardness and tensile strength based on time-temperature-property(TTP) curves and can determine properties based on the temperature histories. The constants($K_1{\sim}K_5$) of QFA were determined using hardness data obtained after various cooling rates. In the current study, a rear side member was selected for evaluation and FE-simulations were performed to obtain the temperature histories during hot stamping. The predicted temperature data were imported into the QFA to calculate the hardness distribution of the hot stamped parts. A hot stamping experiment of the rear side member was conducted to verify the predicted hardness. The simulation results show good agreement with the experimental measurements.

• 한국태양에너지학회 논문집
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• 제33권3호
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• pp.107-113
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• 2013

In this study, three different types of experimental models of BIPV curtain wall units with GIGS modules were built, and their thermal and electrical performances were analyzed. The experimental results showed that the temperature of the rear side of the GIGS module with the application of an insulation in the curtain wall spandrels was higher than a GIGS module standalone by $22^{\circ}C$, which results in a reduction in the power generation of the former by 8 %. On the other hand, when ventilation was applied to the model to improve the power generation performance, the module temperature was observed to be $142^{\circ}C$ lower compared to the enclosed type, and the power generation performance improved by 5 %. It confirmed that the temperature increase in the rear side of the GIGS module with insulation layer reduced the electrical performance of the module. Based on this, it is claimed that providing sufficient ventilation at the GIGS applied spandrels contribute to improve the power generation of the GIGS module.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 춘계학술대회논문집
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• pp.51-53
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• 2008

The vehicle aerodynamic crosswind characteristics are mainly governed by the coefficient of side force and yawing moment. These performances affect not only the driving comfort which can be felt by driver but also the safety due to the instability of vehicle. The aims of this investigation are to improve the aerodynamic crosswind performance of sedan vehicle under the crosswind conditions. In order to improve the crosswind stability, numerical analysis has been performed by modifying the rear body shape of vehicle. As the results, we observed about 20% reduction of yawing moment coefficient relative to the base vehicle.

• 한국ITS학회 논문지
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• 제15권5호
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• pp.71-82
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• 2016

C-ITS 단위 서비스 중 차량 추돌방지 지원 서비스는 위험상황 교통안전을 지원하나, 교통량이 많아 주변에 V2V 통신대상 차량이 많은 경우 V2V 통신부하로 인한 통신 지연 및 실패 가능성이 존재하여 서비스 효용성이 변화할 수 있다. 본 연구는 교통량이 증가하여 혼잡한 도로에서 V2V 통신 과다로 인한 차량 추돌방지 지원 서비스가 실패에 따른 도로 네트워크 영향을 모의실험으로 분석한 정량적 결과를 제시한다. 교통량 조건을 낮은 수준(서비스 수준 A) 높은 수준(서비스 수준 E)까지 변화하며, V2V 통신 실패율을 0%에서 100%까지 극단적인 상황을 포함하여 10% 씩 증가시키면서 차량 추돌방지 지원 서비스 효용성을 잠재상충 발생 건수를 지표로 분석하였다. 분석 결과 차량 1대당 잠재상충 발생 건수가 낮은 교통량 상황 대비 높은 교통량 상황에서 30% 수준 증가하는 것으로 확인되었다. 교통량이 충분히 증가하는 경우 통신 실패율 10% 증가에 따라 잠재상충 발생 건수가 14%씩 증가하는 것으로 분석되었다. C-ITS 단위 서비스 구현을 위한 기존 장비중심의 연구와 더불어 서비스의 효용성을 높일 수 있는 도로교통 운영분야 연구가 병행될 필요가 있음을 제언한다.

• 자동차안전학회지
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• 제5권2호
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• pp.5-10
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• 2013

The pole side crash caused fatal injury by comparison with other crash impact mode such as frontal and rear crash. EuroNCAP proposed the pole side crash test using WorldSID(World Side Impact Dummy). The objective of this study is to develop the pole side impact sled test using dummy rib deflection between crash and sled test. In the pursuit of this purpose, we fabricated new pole side sled buck and test preliminary pole sled using ES-2re. Through this, we found the sled acceleration pulse scale. Hardness and thickness of the EPP affects the rib deflection. We conducted the pole sled test using WorldSID based on the preliminary results. As a result, rib deflection was shown to correlate well between crash test and pole side sled test.

• 한국자동차공학회논문집
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• 제12권1호
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• pp.138-144
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• 2004

Occupant protection in the side impact of a vehicle becomes one of the most important issues today. So, to reduce development time and cost, it needs test equipment which conducts an accurate simulation of the side impact crash. This paper describes a new test method for side impact, which utilizes a standard 12inch-HYGE-type sled facility. If a side impact sled test can simulate vehicle intrusion very well, it will contribute to develop full-scale side impact crash performance. The newly developed sled test method enables simulation for dummy motion, injury, door velocity, trim crack, and vehicle structure to be accurate. Ant also this sled test method can be applied to the development of side air-bag.

• Current Photovoltaic Research
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• 제4권4호
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• pp.145-149
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• 2016

Characteristic of aluminum-silicon alloy paste which is applied on the rear side of PERC cell was investigated. The paste was made by aluminum-silicon alloy with eutectic composition to avoid the formation of void which is responsible for the degradation of the open-circuit voltage. Also, the glass frit component of the paste was changed to improve the adhesion of aluminum-silicon paste. We observed the formation of void and local back surface field between aluminum electrode and silicon base by SEM. The light IV, quantum efficiency and reflectance of the solar cells were characterized and compared for each paste.

• 한국해양공학회지
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• 제31권2호
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• pp.130-140
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• 2017

Typically, a submerged breakwater is one of the good scene-friendly coastal structures used to reduce wave energy and coastal erosion. However, sometimes, a submerged breakwater also has a negative aspect in that a strong rip current occurring around an open inlet due to a difference in mean water levels on the front and rear sides of the structure leads to scouring. Such scouring has a bad effect on its stability. In order to eliminate this kind of demerit, this study investigated four new types of submerged breakwaters with drainage channels. First, hydraulic experiments were performed the typical and new structures. Then, the wave height and mean water level distributions around the structures were examined using the experimental results. Finally, it was revealed that the new type of submerged breakwater could efficiently reduce the mean water level on its rear side. In particular, in the case of new-type submerged breakwater 2, an average reduction efficiency of 71.2% for the difference between the mean water levels at the front and rear sides was shown in comparison with the typical one.