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Digital Communications and Networking

2004

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Articles 1 - 13 of 13

Full-Text Articles in Computer Engineering

Power-Stepped Protocol: Enhancing Spatial Utilization In A Clustered Mobile Ad Hoc Network, Chansu Yu, Kang G. Shin, Ben Lee Sep 2004

Power-Stepped Protocol: Enhancing Spatial Utilization In A Clustered Mobile Ad Hoc Network, Chansu Yu, Kang G. Shin, Ben Lee

Electrical Engineering & Computer Science Faculty Publications

While most previous studies on mobile ad hoc networks (MANETs) rely on the assumption that nodes are randomly distributed in the network coverage area, this assumption is unlikely to hold, as nodes tend to be cluttered around hot spots like the site of an accident or disaster. We refer to this as a clustered layout. Intuitively, a MANET with the clustered layout may suffer from serious performance degradation due to the excessive collisions in congested hot spots and space underutilization of sparse areas. In this paper, we propose a power-controlled network protocol, called the power-stepped protocol (PSP), that maximizes the ...


Ultra Wideband Communication Link, Preeti Singh Aug 2004

Ultra Wideband Communication Link, Preeti Singh

Theses

Ultra-wideband communication (UWB) has been a topic of extensive research in recent years especially for its short-range communication and indoor applications. The preliminary objective of the project was to develop a description and understanding of the basic components of the communication link at microwave frequencies in order to achieve the primary objective of establishing a communication setup at a bandwidth of 2.5 GHz for testing Ultra Wideband (UWB) antennas. This was achieved with the aid of commercially available optical system which was modified for the purpose. Beginning with the generation of baseband narrow pulses with energy spanning over a ...


Qos Provisioning For Multi-Class Traffic In Wireless Networks, Mona El-Kadi Rizvi Jul 2004

Qos Provisioning For Multi-Class Traffic In Wireless Networks, Mona El-Kadi Rizvi

Computer Science Theses & Dissertations

Physical constraints, bandwidth constraints and host mobility all contribute to the difficulty of providing Quality of Service (QoS) guarantees in wireless networks. There is a growing demand for wireless networks to support all the services that are available on wired networks. These diverse services, such as email, instant messaging, web browsing, video conferencing, telephony and paging all place different demands on the network, making QoS provisioning for wireless networks that carry multiple classes of traffic a complex problem. We have developed a set of admission control and resource reservation schemes for QoS provisioning in multi-class wireless networks.

We present three ...


Energy-Aware Ad Hoc On-Demand Distance Vector Routing Protocol And Optimizing The Blocking Problem Induced In Wireless Ad Hoc Networks, Abdallah El Moutia Mar 2004

Energy-Aware Ad Hoc On-Demand Distance Vector Routing Protocol And Optimizing The Blocking Problem Induced In Wireless Ad Hoc Networks, Abdallah El Moutia

FIU Electronic Theses and Dissertations

The purpose of this thesis was to investigate some of the issues related to routing and medium access control protocol in ad hoc networks. In routing protocol, the goal is to tackle the power consumption problem and to present a case for using new cost energy-aware metric for Ad Hoc On-Demand Distance Vector (AODV). The idea of the new cost metric is to be able to avoid routes with a low energy capacity. By using this approach, high efficiency in energy consumption can be achieved in Ad-Hoc networks.

The second goal of this thesis was to investigate the blocking problem ...


Ultra-Wideband (Uwb) Communications: New Paradigms And Opportunities, Robert H. Morelos-Zaragoza Mar 2004

Ultra-Wideband (Uwb) Communications: New Paradigms And Opportunities, Robert H. Morelos-Zaragoza

Robert Henry Morelos-Zaragoza

In this talk, the unique characteristics of ultra wideband (UWB) communications systems are introduced. Receiver design considerations are presented. Focus is on the relation between the symbol duration and the delay spread of the channel. This determines whether the receiver should use a Rake receiver (Spread-spectrum system) or an equalizer (multiple carrier or OFDM system).


Stochastic Analysis And Performance Evaluation Of Wireless Schedulers, R. Rom, Hwee-Pink Tan Feb 2004

Stochastic Analysis And Performance Evaluation Of Wireless Schedulers, R. Rom, Hwee-Pink Tan

Research Collection School Of Information Systems

In the last few years, wireless scheduling algorithms have been proposed by supplementing wireline scheduling algorithms with a wireless adaptation scheme. However, Quality of Service (QoS) bounds have either been derived for flows that perceive error-free conditions or a static worst-case channel condition. Such an assumption of the channel condition is unrealistic, since channel errors are known to be bursty in nature. Hence, these bounds are inadequate to characterize the scheduler's QoS performance. Our research focuses on performing an extensive analysis of wireless scheduling in order to derive statistical QoS performance bounds under realistic channel conditions. In this paper ...


Would Mandating Network Neutrality Help Or Hurt Broadband Competition? A Comment On The End-To-End Debate, Christopher S. Yoo Jan 2004

Would Mandating Network Neutrality Help Or Hurt Broadband Competition? A Comment On The End-To-End Debate, Christopher S. Yoo

Faculty Scholarship at Penn Law

No abstract provided.


Metadata And Buckets In The Smart Object, Dumb Archive (Soda) Model, Michael L. Nelson, Kurt Maly, Delwin R. Croom Jr., Steven W. Robbins Jan 2004

Metadata And Buckets In The Smart Object, Dumb Archive (Soda) Model, Michael L. Nelson, Kurt Maly, Delwin R. Croom Jr., Steven W. Robbins

Computer Science Faculty Publications

We present the Smart Object, Dumb Archive (SODA) model for digital libraries (DLs), and discuss the role of metadata in SODA. The premise of the SODA model is to "push down" many of the functionalities generally associated with archives into the data objects themselves. Thus the data objects become "smarter", and the archives "dumber". In the SODA model, archives become primarily set managers, and the objects themselves negotiate and handle presentation, enforce terms and conditions, and perform data content management. Buckets are our implementation of smart objects, and da is our reference implementation for dumb archives. We also present our ...


Resource Harvesting Within The Oai-Pmh Framework, Herbert Van De Sompel, Michael L. Nelson, Carl Lagoze, Simeon Warner Jan 2004

Resource Harvesting Within The Oai-Pmh Framework, Herbert Van De Sompel, Michael L. Nelson, Carl Lagoze, Simeon Warner

Computer Science Faculty Publications

Motivated by preservation and resource discovery, we examine how digital resources, and not just metadata about resources, can be harvested using the Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH). We review and critique existing techniques for identifying and gathering digital resources using metadata harvested through the OAI-PMH. We introduce an alternative solution that builds on the introduction of complex object formats that provide a more accurate way to describe digital resources. We argue that the use of complex object formats as OAI-PMH metadata formats results in a reliable and attractive approach for incremental harvesting of resources using the OAI-PMH.


A Predictive Sensor Network Using Ant System, Rajani Muraleedharan, Lisa Ann Osadciw Jan 2004

A Predictive Sensor Network Using Ant System, Rajani Muraleedharan, Lisa Ann Osadciw

Electrical Engineering and Computer Science

The need for a robust predictive sensor communication network inspired this research. There are many critical issues in a communication network with different data rate requirements, limited power and bandwidth. Energy consumption is one of the key issues in a sensor network as energy dissipation occurs during routing, communication and monitoring of the environment. This paper covers the routing of a sensor communication network by applying an evolutionary algorithm- the ant system. The issues considered include optimal energy, data fusion from different sensor types and predicting changes in environment with respect to time.


Attack-Resistant Location Estimation In Wireless Sensor Networks, Dongdang Liu, Peng Ning, An Liu, Cliff Wang, Wenliang Kevin Du Jan 2004

Attack-Resistant Location Estimation In Wireless Sensor Networks, Dongdang Liu, Peng Ning, An Liu, Cliff Wang, Wenliang Kevin Du

Electrical Engineering and Computer Science

Many sensor network applications require sensors’ locations to function correctly. Despite the recent advances, location discovery for sensor networks in hostile environments has been mostly overlooked. Most of the existing localization protocols for sensor networks are vulnerable in hostile environments. The security of location discovery can certainly be enhanced by authentication. However, the possible node compromises and the fact that location determination uses certain physical features (e.g., received signal strength) of radio signals make authentication not as effective as in traditional security applications. This paper presents two methods to tolerate malicious attacks against range-based location discovery in sensor networks ...


A Predictive Sensor Network Using Ant System, Rajani Muraleedharan, Lisa Ann Osadciw Jan 2004

A Predictive Sensor Network Using Ant System, Rajani Muraleedharan, Lisa Ann Osadciw

Electrical Engineering and Computer Science

The need for a robust predictive sensor communication network inspired this research. There are many critical issues in a communication network with different data rate requirements, limited power and bandwidth. Energy consumption is one of the key issues in a sensor network as energy dissipation occurs during routing, communication and monitoring of the environment. This paper covers the routing of a sensor communication network by applying an evolutionary algorithm- the ant system. The issues considered include optimal energy, data fusion from different sensor types and predicting changes in environment with respect to time.


Future Of Asynchronous Transfer Mode Networking, Fakhreddine Mohamed Hachfi Jan 2004

Future Of Asynchronous Transfer Mode Networking, Fakhreddine Mohamed Hachfi

Theses Digitization Project

The growth of Asynchronous Transfer Mode (ATM) was considered to be the ideal carrier of the high bandwidth applications like video on demand and multimedia e-learning. ATM emerged commercially in the beginning of the 1990's. It was designed to provide a different quality of service at a speed up 100 Gbps for both real time and non real time application. The turn of the 90's saw a variety of technologies being developed. This project analyzes these technologies, compares them to the Asynchronous Transfer Mode and assesses the future of ATM.