A great number of people spend one or more hours each day driving between home and the office. These daily roadway commutes are highly predictable and regular, and provide a great opportunity to form virtual mobile communities. However, even though these commuters are already physically present in the same location, they are limited in their ability to communicate with each other. This paper presents a framework for building such communities, which we call Vehicular Social Networks (VSNs), to facilitate better communication between commuters driving on roadways. As a proof of concept, we present the design of RoadSpeak, a VSN-based system that allows drivers to automatically join VSNs along popular roadways, and to communicate with each other by means of voice chat messages. 1.

Abstract—In this paper, we introduce a novel roadside unit (RSU)-aided message authentication scheme named RAISE, which makes RSUs responsible for verifying the authenticity of messages sent from vehicles and for notifying the results back to vehicles. In addition, RAISE adopts the k-anonymity property for preserving user privacy, where a message cannot be associated with a common vehicle. In the case of the absence of an RSU, we further propose a supplementary scheme, where vehicles would cooperatively work to probabilistically verify only a small percentage of these message signatures based on their own computing capacity. Extensive simulations are conducted to validate the proposed scheme. It is demonstrated that RAISE yields a much better performance than previously reported counterparts in terms of message loss ratio (LR) and delay. Index Terms—Cooperation, privacy, security, vehicular communications.

Abstract—Delay-tolerant networks (DTNs) provide a promising solution to support wide-ranging applications in the regions where end-to-end network connectivity is not available. In DTNs, the intermediate nodes on a communication path are expected to store, carry, and forward the in-transit messages (or bundles) in an opportunistic way, which is called opportunistic data forwarding. Such a forwarding method depends on the hypothesis that each individual node is ready to forward packets for others. This assumption, however, might easily be violated due to the existence of selfish or even malicious nodes, which may be unwilling to waste their precious wireless resources to serve as bundle relays. To address this problem, we propose a secure multilayer credit-based incentive scheme to stimulate bundle forwarding cooperation among DTN nodes. The proposed scheme can be implemented in a fully distributed manner to thwart various attacks without relying on any tamperproof hardware. In addition, we introduce several efficiency optimization techniques to improve the overall efficiency by exploiting the unique characteristics of DTNs. Extensive simulations demonstrate the efficacy and efficiency of the proposed scheme. Index Terms—Delay-tolerant networks (DTNs), incentive scheme, security. I.

Abstract—Vehicular ad hoc networks (VANETs) are envisioned to provide promising applications and services. One critical deployment issue in VANETs is to motivate vehicles and their drivers to cooperate and contribute to packet forwarding in vehicle-to-vehicle or vehicle-to-roadside communication. In this paper, we examine this problem, analyze the drawbacks of two straightforward schemes, and present a secure incentive scheme to stimulate cooperation in VANETs. We define the measurement of contribution according to the unique characteristics of VANET communication. Our scheme uses the weighted rewarding component to ensure fairness. Extensive simulation results are presented to support the effectiveness of our scheme.

Abstract—Beyond the initial focus on vehicular safety application, there is considerable scope for the development of other information-rich applications which can provide convenience and comfort features to drivers and passengers. We argue that an Internet-like end-to-end networking framework might not always be the best fit for the unique nature of vehicular application — spatially and temporally localized, dynamic, and dataintensive. In this research challenge paper, we propose a top-down framework called Information-Centric Networking on Wheels (IC NoW) to develop a generic network architecture supporting futuristic information-rich VANET applications, ranging from location based services to real-time audio/video transfer. The key design philosophy of our proposed framework is that VANET communication is scoped by three key characteristics of information relevance: space, time, and user interest. Using this philosophy, we advocate the development of protocols for information dissemination and management that allow for localized, in-network operations. An important feature of the proposed IC NoW framework is that protocols and applications are implemented in a distributed manner using local decision rule sets taking into account fresh local information. We also pay special attention to ensure the proposed framework is easy to interface with existing cellular infrastructure, whenever needed. This framework enables modular design, facilitating easy application development and creating a smooth migration path during the deployment evolution path. I.

Abstract—Vehicular ad hoc networks (VANETs) are envisioned to provide promising applications and services. One critical deployment issue in VANETs is to motivate vehicles and their drivers to cooperate and contribute to packet forwarding in vehicle-to-vehicle or vehicle-to-roadside communication. In this paper, we examine this problem, analyze the drawbacks of two straightforward schemes, and present a secure incentive scheme to stimulate cooperation and contribution in VANETs. We first define the measurement of contribution according to the unique characteristics of VANET communication. Our scheme uses the weighted rewarding component to ensure fairness. I.

of the non-existence of end-to-end connections, it is essential that nodes take advantage of connection opportunities to forward messages, to make end-to-end messaging possible. Thus it is crucial to make sure that nodes have incentives to forward messages for others, despite that the routing protocols in VANETs are different from traditional end-to-end routing protocols. In this paper, we study how to stimulate message forwarding in VANETs. Our approach is based on coalitional game theory. In particular, we propose an incentive scheme for VANETs and rigorously show that with our scheme faithfully following the routing protocol is to the best interests of each node. In addition, we extend our scheme to take the limited storage space of each node into consideration. Experiments on testbed trace data verify that our scheme is effective in stimulating cooperation of message forwarding in VANETs. I.

Vehicular ad hoc networks present challenging characteristics, such as very dynamic behavior and sparse connectivity, that need to be taken into account in designing adequate communication support. Gossip-based protocols have recently emerged as an effective approach to providing reliable and efficient communication in this domain. Nonetheless, despite the preliminary encouraging results, to the best of our knowledge, no previous work has systematically analyzed how gossip protocols are affected by the intrinsic characteristics of vehicular networks such as the very specific mobility patterns of vehicles, the relative abundance of memory and computational resources that vehicles offer, and the availability of geographical information through GPS receivers. In this paper, we aim at filling this gap by examining core requirements of vehicular network applications and analyzing the research challenges that gossip-based communication protocols need to address.

Abstract—Vehicular Ad hoc Network (VANET) is a kind of mobile ad hoc network using the capabilities of wireless communication for Vehicle-to-Vehicle and Vehicle-to-Roadside communication to provide safety and comfort to vehicles in transportation system. People in vehicles want to access data of their interest from Road Side Unit (RSU). RSU need to schedule these requests in a way to maximize the service ratio. In this paper we have proposed new methods for careful analysis of incoming requests to find whether these requests can be completed within deadline or not and to provide dynamic service queue. Simulation results show that the proposed schemes increase the service ratio significantly.

While it took the radio 38 years and the television a short 13 years, it took the World Wide Web only 4 years to reach 50 million users. This shows the richness of the pace at which the computer science moves. As 2012 progresses, we seem to be set for the rapid and intricate ramifications of new technology advancements. With this issue we wish to reach out to a much larger number with an expectation that more and more researchers get interested in our mission of sharing wisdom. The Organization is committed to introduce to the research audience exactly what they are looking for and that is unique and novel. Guided by this mission, we continuously look for ways to collaborate with other educational institutions worldwide. Well, as Steve Jobs once said, Innovation has nothing to do with how many R&D dollars you have, it’s about the people you have. At IJACSA we believe in spreading the subject knowledge with effectiveness in all classes of audience. Nevertheless, the promise of increased engagement requires that we consider how this might be accomplished, delivering up-to-date and authoritative coverage of advanced computer science and applications. Throughout our archives, new ideas and technologies have been welcomed, carefully critiqued, and discarded or accepted by qualified reviewers and associate editors. Our efforts to improve the quality of the articles published and expand their reach to the interested audience will continue, and these efforts will require critical minds and careful consideration to assess the quality, relevance, and readability of individual articles.