Current Issue : January - March Volume : 2016 Issue Number : 1 Articles : 5 Articles
As an important infrastructure of intelligent transportation system (ITS), vehicular ad hoc networks (VANETs) provide navigation\nand positioning, information services, driver assistance, in-vehicle entertainment, and other functions for the owners improving\nthe development of the future smart city. Due to the high dynamic nature of VANETs, choosing a relatively stable and reliable\ntransmission path to reduce the link breakage is obviously very important. In this paper, we propose an efficient prediction based\ndata forwarding strategy to ensure the reliability and efficiency of data transmission in VANETs. Besides the link lifetime\nprediction, we introduce a new metric named link utility used in the process of forwarder selection, in order to improve data\nforwarding efficiency. Link utility reflects the impact of relative velocity and distance between the vehicles on the efficiency of\ninter vehicle data transmissions. It can be used to optimize packet routing and minimize number of hops especially in the high density\nVANETs. Finally, we evaluate the performance of the proposed forwarding strategy through simulation confirming its\nfeasibility and effectiveness....
In order to study the damage of a semirigid pavement under vehicle loads with varied parameters, the random dynamic loads\napplied on the pavement by a running vehicle were computed with two degrees of freedom, quarter-vehicle model, and then a\nthree-dimensional finite element analysis model of semirigid asphalt pavement was established.With the peak stress index of each\npavement layer, the effect of varied vehicle parameters on pavement response was studied. The results indicated that the stress\nwave frequency of each pavement layer was similar to that of the dynamic random load, and, with increased pavement depth, the\nwave effect decreased. The pavement response increased with increased suspension stiffness and tire stiffness and decreased with\nincreased suspension damping and tire damping. Furthermore, compared to the stiffness, the response variation induced by the\ndamping was orders of magnitude lower. Compared with the traditional time response analysis method, the peak response analysis\nof the pavement structure was more scientific, rational, and intuitive, which could be useful for the study of vehicle-pavement\ninteraction and road damage....
Fuel cells offer an enabling alternative energy technology for the present day useful energy crisis. However, one\nof the major obstacles of fuel cells in powering motor vehicles is the enormous cost associated with the catalysts\nused in both half-reactions which are Pt and Pt-Rh, respectively, for the anodic and cathodic half-reactions. Among\nseveral strategies put forward to reduce the cost of fuel cells, lowering of the amount of platinum used and replacing\nhighly expensive platinum by low-cost catalysts are two major approaches to realize the development of fuel cell-\n \n\n\n\n\n\n\n\n\n\n\n\n\n\nviz., the oxygen reduction half reaction of the fuel cells. We present here the development and the activity of Ag/\nPolypyrrole/Montmorillonite Clay catalyst which performs equally to expensive Pt-Rh catalyst used for the oxygen\nreduction half-reaction of fuel cells. We show that this catalyst functions very similar to highly expensive Pt-Rh\ncatalyst and hence the former can be conveniently substituted for the latter in practical applications....
Vehicle driving safety is the urgent key problem to be solved of automobile independent development while encountering\nemergency collision avoidance with high speed. And it is also the premise and one of the necessary conditions of vehicle active\nsafety. A new technique of vehicle handling inverse dynamics which can evaluate the emergency collision avoidance performance\nis proposed. Based on optimal control theory, the steering angle input and the traction/brake force imposed by driver are the control\nvariables; the minimum time required to complete the fitting biker line change is the control object. By using the improved direct\nmultiple shooting method, the optimal control problem is converted into a nonlinear programming problem that is then solved\nby means of the sequential quadratic programming. The simulation results show that the proposed method can solve the vehicle\nminimum time maneuver problem, and can compare the maneuverability of two different vehicles that complete fitting biker line\nchange with the minimum time and the correctness of the model is verified through real vehicle test....
We propose a reflective optics design for an LED motorbike high beam lamp.We set the measuring screen as an elliptical zone and\ndivide it into many small lattices and divide the spatial angle of the LED source into many parts and make relationships between\nthem. According to the conservation law of energy and the Snell�s law, the reflector is generated by freeform optics design method.\nThen the optical system is simulated by Monte Carlo method using ASAP software. Light pattern of simulation could meet the\nstandard.The high beam headlamp is finally fabricated and assembled into a physical object. Experiment results can fully comply\nwith United Nations Economic Commission for Europe (ECE) vehicle regulations R113 revision 2 (Class C)....
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