Department of Computer Science Activity 1998-2004

This report summarizes much of the research and teaching activity of the Department of Computer Science at Dartmouth College between late 1998 and late 2004. The material for this report was collected as part of the final report for NSF Institutional Infrastructure award EIA-9802068, which funded equipment and technical staff during that six-year period. This equipment and staff supported essentially all of the department\u27s research activity during that period

Game theoretic approach in routing protocols for wireless mobile ad hoc networks

Mobile Ad hoc Networks (MANETs) are becoming popular as a means of providing communication among a group of people. Because of self-configuring and self-organizing characteristics, MANETs can be deployed quickly. There is no infrastructure defined in the network, therefore all of the participating nodes relay packets for other nodes and perform routing if necessary. Because of the limitations in wireless transmission range, communication links could be multi-hop. Routing protocol is the most important element of MANET. Routing protocols for MANET can broadly be classified as proactive routing protocol and reactive routing protocol. In proactive routing protocols like Destination Sequence Distance Vector (DSDV), mobile nodes periodically exchange routing information among themselves. Hence proactive routing protocols generate high overhead messages in the network. On the other hand, reactive routing protocols like Ad hoc On-demand Distance Vector (AODV) and Dynamic Source Routing (DSR) work on-demand. Hence reactive routing protocols generate fewer number of overhead messages in the network compared to proactive routing protocols. But reactive routing protocols use a global search mechanism called flooding during the route discovery process. By flooding mechanism a source node can discover multiple routes to a destination. Flooding generates a large number of overhead packets in the network and is the root cause of scaling problem of reactive routing protocols. Hierarchical Dynamic Source Routing (HDSR) protocol has been proposed in this dissertation to solve that scaling problem. The DSR protocol has been modified and optimized to implement HDSR protocol. HDSR protocol reduces the flooding problem of reactive routing protocols by introducing hierarchy among nodes. Two game theoretic models, Forwarding Dilemma Game (FDG) and Forwarding Game Routing Protocol (FGRP), is proposed to minimize the \u27flooding\u27 effect by restricting nodes that should participate in route discovery process based on their status. Both FDG and FGRP protocols reduce overhead packet and improve network performances in terms of delay packet delivery ratio and throughput. Both protocols were implemented in AODV and the resulting protocol outperformed AODV in our NS-2 simulations. A thorough connectivity analysis was also performed for FDG and FGRP to ensure that these protocols do not introduce disconnectivity. Surprisingly, both FDG and FGRP showed better connectivity compared to AODV in moderate to high node density networks

Scalable Storage for Digital Libraries

I propose a storage system optimised for digital libraries. Its key features are its heterogeneous scalability; its integration and exploitation of rich semantic metadata associated with digital objects; its use of a name space; and its aggressive performance optimisation in the digital library domain

Recent Developments on Mobile Ad-Hoc Networks and Vehicular Ad-Hoc Networks

This book presents collective works published in the recent Special Issue (SI) entitled "Recent Developments on Mobile Ad-Hoc Networks and Vehicular Ad-Hoc Networks”. These works expose the readership to the latest solutions and techniques for MANETs and VANETs. They cover interesting topics such as power-aware optimization solutions for MANETs, data dissemination in VANETs, adaptive multi-hop broadcast schemes for VANETs, multi-metric routing protocols for VANETs, and incentive mechanisms to encourage the distribution of information in VANETs. The book demonstrates pioneering work in these fields, investigates novel solutions and methods, and discusses future trends in these field

Telecommunications Networks

This book guides readers through the basics of rapidly emerging networks to more advanced concepts and future expectations of Telecommunications Networks. It identifies and examines the most pressing research issues in Telecommunications and it contains chapters written by leading researchers, academics and industry professionals. Telecommunications Networks - Current Status and Future Trends covers surveys of recent publications that investigate key areas of interest such as: IMS, eTOM, 3G/4G, optimization problems, modeling, simulation, quality of service, etc. This book, that is suitable for both PhD and master students, is organized into six sections: New Generation Networks, Quality of Services, Sensor Networks, Telecommunications, Traffic Engineering and Routing

The impact of inter-vehicle communication on vehicular traffic

The work addresses communication networks established over radio equipped vehicles in our everyday road traffic, so called Vehicular Ad Hoc Networks (VANETs), and discusses their impact on two major goals, namely traffic safety and traffic efficiency. For both objectives, the thesis proposes an appropriate modeling of the essential building blocks Traffic, Communication and Application and enables impact assessment studies by means of implemented simulation tools

Building Internet caching systems for streaming media delivery

The proxy has been widely and successfully used to cache the static Web objects fetched by a client so that the subsequent clients requesting the same Web objects can be served directly from the proxy instead of other sources faraway, thus reducing the server\u27s load, the network traffic and the client response time. However, with the dramatic increase of streaming media objects emerging on the Internet, the existing proxy cannot efficiently deliver them due to their large sizes and client real time requirements.;In this dissertation, we design, implement, and evaluate cost-effective and high performance proxy-based Internet caching systems for streaming media delivery. Addressing the conflicting performance objectives for streaming media delivery, we first propose an efficient segment-based streaming media proxy system model. This model has guided us to design a practical streaming proxy, called Hyper-Proxy, aiming at delivering the streaming media data to clients with minimum playback jitter and a small startup latency, while achieving high caching performance. Second, we have implemented Hyper-Proxy by leveraging the existing Internet infrastructure. Hyper-Proxy enables the streaming service on the common Web servers. The evaluation of Hyper-Proxy on the global Internet environment and the local network environment shows it can provide satisfying streaming performance to clients while maintaining a good cache performance. Finally, to further improve the streaming delivery efficiency, we propose a group of the Shared Running Buffers (SRB) based proxy caching techniques to effectively utilize proxy\u27s memory. SRB algorithms can significantly reduce the media server/proxy\u27s load and network traffic and relieve the bottlenecks of the disk bandwidth and the network bandwidth.;The contributions of this dissertation are threefold: (1) we have studied several critical performance trade-offs and provided insights into Internet media content caching and delivery. Our understanding further leads us to establish an effective streaming system optimization model; (2) we have designed and evaluated several efficient algorithms to support Internet streaming content delivery, including segment caching, segment prefetching, and memory locality exploitation for streaming; (3) having addressed several system challenges, we have successfully implemented a real streaming proxy system and deployed it in a large industrial enterprise