Because of the various constraints imposed on ad hoc mobile wireless networks, a cost efficient routing protocol is crucial to the success of an ad hoc mobile wireless network, especially in a dynamic environment such as battlefields. In this paper, we present a cost efficient routing scheme for ad hoc mobile networks by taking advantages of the benefits of traffic aggregation. The central idea of our proposed routing scheme is motivated by the observation that traffic aggregation can reduce the effects of traffic variations. Based on similar studies in the fixed networks, we device a more realistic cost model in ad hoc mobile wireless networks, and propose a routing scheme based on this cost model that effectively promotes the traffic sharing in ad hoc mobile wireless networks. A much higher traffic variation factor than in fixed networks is used to account for the higher traffic fluctuations in an ad hoc mobile wireless network environment.
The reserved delivery service can help the information service providers to provide more consistent performance to their customers by the provisioning of reserved bandwidth on a delivery subnetwork. However, the configuration problem of a reserved delivery subnetwork is a hard optimization problem with no efficient exact algorithm besides exhaust searches. In this paper, we introduce a reserved delivery subnetwork configuration algorithm based on an idea of the maximum sharing shortest path tree (MSSPT). The proposed algorithm is motivated by the observation that the path sharing of multiple flows
reduce the cost in reserved delivery subnetworks. Thus, a solution close to the optimal could occur in a subnetwork with the maximum degree of flow sharing. The maximum sharing shortest path tree problem can be categorized as a multicriteria shortest path problem. Using an algorithm based on the shortest path network (SPN, a unique subnetwork in which every path s → u is a shortest path in the original graph), we develop an efficient algorithm for the maximum sharing shortest path problem. The proposed algorithm is an approximation algorithm in nature because it takes the MSSPT as the
approximation solution to the reserved delivery subnetwork configuration problem. Our experimental results show that the
proposed algorithm has good performance against an easily computed lower bound, but has time complexity comparable to a single source shortest path algorithm.
Video applications over the Internet are getting increasingly popular because of the explosive growth of the Internet. However, video packets loss due to network congestions can degrade the video quality substantially. In this paper, we propose a transmission scheme for Motion-JPEG2000 video sequences with an active networking approach. Our scheme utilizes the progression modes in Motion-JPEG2000. It can be implemented in an active network environment efficiently. Our simulation shows that the proposed scheme gracefully adapts to network congestion and improves the quality of video transmission in congested IP networks.
High quality video conferencing is an efficient tool for interactive scientific collaboration in the research community, especially for researchers separated by substantial distance. With the wide deployment of broadband wide area IP networks such as the Internet2, there is an increasing demand for improved remote collaboration with these networks. In order to make the high quality video-conferencing toolkits for local high-speed networks available over wide area IP networks, issues that are usually insignificant on local area networks must be considered. To this end, we have developed called Adaptation Layer Translator (ALX) in order to address these issues and solve the problems associated with real-time video and audio transmission over wide area IP networks. A conference control protocol is developed to coordinate the participants in an ALX-based conference. The ALX is also designed to be able to adapt to heterogeneous network environments at different deployment sites.
The new ISO/ITU-T standard for still image coding, JPEG2000, has been shown to provide superior coding efficiency to the previous standard, JPEG. Because of the superb performance of JPEG2000, it is reasonable to argue that Motion-JPEG2000, the corresponding moving picture coding standard of JPEG2000, has equally outstanding performance. However, there has not been a sufficient performance evaluation of Motion-JPEG2000. To this end, we have studied the potential of Motion-JPEG2000 for video processing. Our experiments show that Motion-JPEG2000 provides high compression performance, strong error resilience, and good perceptual image quality. Together with a rich set of features inherited from JPEG2000, Motion-JPEG2000 has advantages as a coding standard for video processing in many applications.