Demonstration of vehicular visible light communication based on LED headlamp

With the emergence of LED lighting, IT convergence technology using the visible spectrum of LEDs, such as Visible Light Communication (VLC), has been highlighted. Among the many VLC applications, vehicular VLCs based on LED headlamps and transportation lighting infrastructure, such as street lamps, traffic lights, etc., are considered good alternatives for Intelligent Transportation Systems (ITS) or Active Safety applications. This paper introduces a demonstration system of vehicle-to-vehicle (V2V) VLC based on LED headlamps. By applying an inverse 4-PPM modulation scheme satisfying a 75 % dimming level under the light distribution regulation of LED headlamp, the proposed system showed its capability for V2V VLC with a 10 kbps data rate for more than 30 m under day time conditions. By measuring the BER performance according to distance, outdoor V2V VLC was possible for more than 30 m even in the day time.     

Urban driving cycle for performance evaluation of electric vehicles

Nowadays, a number of environmental issues have seriously come to the fore. For this reason, the R & D spending on eco-friendly vehicles that use electric power has been gradually increasing. In general, fuel economy and pollutant emissions of both conventional and eco-friendly vehicles are measured through chassis dynamometer tests that are performed on a variety of driving cycles before an actual driving test. There are a number of driving cycles that have been developed for the for performance evaluation of conventional vehicles. However, there is a lack of research into driving cycle for EV. Because large differences exist between the drive system and driving charateristics of EV and that of CV, a study on driving cycle for EV should be conducted. In this study, the necessity of an urban driving cycle for the performance evaluation of electric vehicles is confirmed by developing the driving cycle. First, the Gwacheon-city Urban Driving Cycle for Electric Vehicles (GUDC-EV) is developed by using driving data obtained through actual driving experiments and statistical analysis. Second, GUDC-EV is verified by constructing EV simulators and performing simulations that use the actual driving data. The simulation results are then compared against existing urban driving cycles, such as FTP-72, NEDC, and Japan 10–15. These results confirm that GUDC-EV can be used as an urban driving cycle to evaluate the performance of electric vehicles and validate the necessity of development of the driving cycle for electric vehicles.     

Numerical Study for Brake Squeal by Machining Patterns on Frictional Surface

Automotive brake noise has become a stubborn problem as automotive cars achieve higher driving torques, since that the increased torque induces the generation of severe noise dissipation during brake operation. Moreover, the global brake tuning market for achieving higher performance of the vehicle has expanded recently. The need to control the noise grows more in this connection. The tuning brake kits have employed cross-drilled and slotted machining pattern on the surface of the rotor. These designs have advantages to improve air ventilation, temperature control, and surface cleaning of brake pad. However, the effects of modal frequency by patterned rotor surfaces are rarely discussed, even if it is highly related with brake squeal phenomenon. Therefore, this study deals with the relationship between patterned surfaces and brake squeal through the numerical methods. The commercial software of a finite element analysis is employed for calculation by varying geometric design factors of each rotor pattern. As a result, the cross-drilled machining patterns are concluded to be an influential factor for in-plane mode frequency while the slotted patterns have more leverage for out-of-plane mode frequency.     

峡谷河流的挂网式人行悬索桥设计

为了降低峡谷河流人行悬索桥的造价,本文提出一种峡谷河流的双曲抛物面空间缆索挂网式人行悬索桥,将双曲抛物面空间缆索网分散锚固于峡谷河流两侧的悬崖陡壁岩石之上,取消桥塔,取消吊索体系,管桁架式桥面加劲梁直接搁置在双曲抛物面空间缆索网之上,节约造价,装配式施工简便。结合某150m跨径峡谷河流人行景观悬索桥,建立Midas有限元分析模型,开展动力模态特性分析研究,验证了双曲抛物面空间缆索挂网式人行悬索桥结构具有良好的抗风稳定性。