Current Issue : October - December Volume : 2016 Issue Number : 4 Articles : 5 Articles
Vehicular Ad-Hoc Networks (VANETs) as a part of intelligent transportation systems (ITS) are a\nnew perspective to settle the traffic problem. Because of the high velocity, variational topology\nand such other characters, the link between VANETs and road side unit (RSU) is unstable. Besides,\non account of the high cost of RSU, some places can�t be covered completely which make the Internet\naccessing difficult and accessing delay long. In this paper, we propose a hierarchical link\nscheme to help vehicles access the Internet based on delay analysis for congestion scenario. We\nselect some moving accessing help points (AHPs) from vehicles in VANETs. Two different hierarchical\nschemes under the circumstances of whole road covered or not are proposed. When the\nRSUs are enough to cover the whole road fully, we propose the inward progressive hierarchical\nmethod. When the RSUs are not enough to cover the whole road, we propose the outward extend\nhierarchical method. According to the delay analysis, we can get the optimal hierarchy number.\nThis hierarchical link scheme can decrease delay and make all vehicles access the Internet with\ndelay guarantee. The simulation results indicate that our proposed hierarchical link scheme in\nVANETs can decrease the link delay effectively....
We propose a dynamic vehicular routing algorithm with traffic prediction for improved routing performance.The primary idea of\nour algorithmis to use real-time aswell as predictive traffic information provided by a central routing controller. In order to evaluate\nthe performance, we develop a microtraffic simulator that provides road networks created from real maps, routing algorithms, and\nvehicles that travel from origins to destinations depending on traffic conditions. The performance is evaluated by newly defined\nmetric that reveals travel time distributions more accurately than a commonly used metric of mean travel time. Our simulation\nresults show that our dynamic routing algorithm with prediction outperforms both Static and Dynamic without prediction routing\nalgorithms under various traffic conditions and road configurations.We also include traffic scenarios where not all vehicles comply\nwith our dynamic routing with prediction strategy, and the results suggest that more than half the benefit of the new routing\nalgorithm is realized even when only 30% of the vehicles comply....
This paper presents a new clustering mechanism for the multi-hop relay in vehicular communication. In the proposed\nmechanism, the cluster-head selection is implemented using the enhanced hybrid wireless mesh protocol (E-HWMP)\nprotocol, which is based on the IEEE802.11p and IEEE802.11s standards. Then, multi-hop routing is designed for VANET\nin Wireless Mesh Networks (WMNs). Therefore, the main aim of this study is to enhance the integration of VANET with\na cellular network (i.e., LTE). As a result, the coverage can be extended. The proposed E-HWMP mechanism is evaluated\nby the NS2 simulator, and the VanetMobiSim is used as a mobility generator. The proposed E-HWMP mechanism is\ncompared to the existing mechanism based on the packet�s delivery ratio, packet loss, throughput, overhead, and\naverage end-to-end delay. The results demonstrate that the proposed E-HWMP mechanism outperforms the existing\nclustering mechanism....
Vehicular ad hoc networks (VANETs) play a vital role in the success of self-driving\nand semi self-driving vehicles, where they improve safety and comfort. Such vehicles depend\nheavily on external communication with the surrounding environment via data control and\nCooperative Awareness Messages (CAMs) exchanges. VANETs are potentially exposed to a number\nof attacks, such as grey hole, black hole, wormhole and rushing attacks. This work presents an\nintelligent Intrusion Detection System (IDS) that relies on anomaly detection to protect the external\ncommunication system from grey hole and rushing attacks. These attacks aim to disrupt the\ntransmission between vehicles and roadside units. The IDS uses features obtained from a trace\nfile generated in a network simulator and consists of a feed-forward neural network and a support\nvector machine. Additionally, the paper studies the use of a novel systematic response, employed to\nprotect the vehicle when it encounters malicious behaviour. Our simulations of the proposed detection\nsystem show that the proposed schemes possess outstanding detection rates with a reduction in\nfalse alarms. This safe mode response system has been evaluated using four performance metrics,\nnamely, received packets, packet delivery ratio, dropped packets and the average end to end delay,\nunder both normal and abnormal conditions....
Similar to conventional vehicle,most in-wheel small EVs that exist today are designed with understeer (US) characteristic.They are\nsafer on the road but possess poor cornering performance.With recent in-wheelmotor and steer-by wire technology, high cornering\nperformance vehicle does not limit to sport or racing cars. We believe that oversteer (OS) design approach for in-wheel small EV\ncan increase the steering performance of the vehicle. However, one disadvantage is that OS vehicle has a stability limit velocity. In\nthis paper, we proposed a Four-Wheel Drive and Independent Steering (4WDIS) for in-wheel small EV with OS characteristic.The\naim of implementing 4WDIS is to develop a high steer controllability and stability of the EV at any velocity. This paper analyses\nthe performance of OS in-wheel small EV with 4WDIS by using numerical simulation. Two cornering conditions were simulated\nwhich are (1) steady-state cornering at below critical velocity and (2) steady-state cornering over critical velocity. The objective\nof the simulation is to understand the behavior of OS in-wheel small EV and the advantages of implementing the 4WDIS. The\nresults show that an in-wheel small EV can achieve high cornering performance at low speed while maintaining stability at high\nspeed....
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