Role Of Vehicles Research Articles

A vehicle's weight‐based prioritized reciprocity MAC

AbstractIn vehicular ad hoc networks, vehicles compete for channel access through the medium access control protocol to transmit messages. Most traditional medium access methods assign the same probability to all vehicles accessing the channel and ignore the intrinsic attributes of different vehicles. Attributes regarding the position and role of a vehicle are important factors to be considered when a vehicle is competing for the channel. In this paper, we introduce a new notion of a weight factor in a fair medium access game and propose a game model to adjust each node's channel access probability with complete information in the vehicular environment based on the weight factors of vehicles. The weight of a vehicle represents a specific property, such as the distance between vehicles, the vehicle's role, and so on, which can be used to distinguish priorities of different vehicles during channel competition. We also provide instances of relevant applications by using the distance between vehicles and a vehicle's role. Then, we analyze the incomplete information game in which each node cannot acquire the previous channel access probabilities of other nodes. Moreover, we construct a distributed best‐response learning algorithm based on the medium access game model and demonstrate that the game can converge to a unique and stable equilibrium under certain conditions. Furthermore, we investigate some performance indicators such as channel access delay and normalized throughput and perform extensive numerical analyses compared with the IEEE 802.11p protocol and an existing game‐based medium access control algorithm without consideration of weights. The performance comparison of high‐priority nodes and all nodes in a network is also studied. Finally, we analyze the effects of the proportion of high‐priority nodes on the performance of the channel. The performance improvement after introducing the weight factor is verified by these numerical results.

The role of motor vehicles in air pollution in the UK

This paper presents an overview of the contribution of motor vehicles to some air pollution issues in the UK. The coverage of issues is selective concentrating primarily on the motor vehicle's role in emissions of carbon dioxide and other greenhouse gases, NO x concentrations in rural and urban areas. Finally some discussion is given of future technological developments in vehicle pollution control technology and some possible air pollution consequences.