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Articles 211 - 240 of 325

Full-Text Articles in OS and Networks

Network Security: A Secure Architecture For Open Source Voip Solutions, Fahad Sattar, M. Hussain, Kashif Nisar Jul 2011

Network Security: A Secure Architecture For Open Source Voip Solutions, Fahad Sattar, M. Hussain, Kashif Nisar

International Conference on Information and Communication Technologies

Voice over IP “VoIP” is a form of voice speech that uses data networks, for transmission of voice traffic over IP-based networks to transmit voice signals. The signal is correctly encoded at one end of the communication channel, sent as packets through the data network, then decoded at the receiving end and transformed back into a voice signal. It has a potential and offering a choice to the traditional telephony systems due to its high resource utilization and cost efficiency. Meanwhile, Wireless Local Area Networks (WLANs) have become an ever present networking technology that has been deployed around the world. …


Networks - I: Interference Mitigation In 4g System Using Smart Antenna, Asad Ali Siddiqui, Muhammad Mazhar Manzoor, Aamir Ijaz, Adnan Umar Khan, Imran Ahmed Awan, Sangita Lal Chand Jul 2011

Networks - I: Interference Mitigation In 4g System Using Smart Antenna, Asad Ali Siddiqui, Muhammad Mazhar Manzoor, Aamir Ijaz, Adnan Umar Khan, Imran Ahmed Awan, Sangita Lal Chand

International Conference on Information and Communication Technologies

Emerging trends of mobile communication and ever growing demand of mobile users with high speed data requirements and migrating towards 4G, Co-Channel interference and multipath in urban/dense urban environment will limit the capacity of the network. Smart antenna is now recognized by its higher user capacity in 4G wireless networks by efficiently reducing multipath and co-channel interference. Smart Antenna use adaptive beam forming algorithms in a dynamic environment continuously adjusting the weight of antenna arrays for creating a beam to track desired users automatically, and minimize interference from other users by placing nulls in their directions. This research work provides …


A Reservation-Based Smart Parking System, Hongwei Wang Jul 2011

A Reservation-Based Smart Parking System, Hongwei Wang

School of Computing: Dissertations, Theses, and Student Research

In metropolitan areas, parking management influences drivers search time and cost for parking spaces, parking revenue, and traffic congestion. The wide deployment of wireless parking meters with sensing and communications capabilities allows the parking authority to monitor the state of each parking space in real time and optimize the parking management.

In this thesis, we study state-of-the-art parking policies in smart parking systems, and show that the smart parking system needs to be "smarter". Our design goals of the smart parking systems include: (1) simplify the operations of parking systems, (2) improve drivers' satisfaction, (3) increase parking revenue, and (4) …


Offline Optimization Of Advance Reservation Of Bandwidth Over Dynamic Circuit Networks, Pragatheeswaran Angu Apr 2011

Offline Optimization Of Advance Reservation Of Bandwidth Over Dynamic Circuit Networks, Pragatheeswaran Angu

School of Computing: Dissertations, Theses, and Student Research

E-science projects require very high-speed and reliable networks to transfer data across various destinations in the world. Dynamic Circuit Network (DCN) is a networking service to make advance reservation of bandwidth between a source and a destination in a network. In this thesis we solve the problem of advance reservation of bandwidth in next-generation wavelength-division multiplexing (WDM) networks using a simulation based approach.
We implement a greedy algorithm and a genetic algorithm in parallel, in separate threads. The request for advance reservation is processed by both but the user gets the response only from the greedy algorithm. The genetic algorithm …


Propeller: A Scalable Metadata Organization For A Versatile Searchable File System, Lei Xu, Hong Jiang, Xue Liu, Lei Tian, Yu Hua, Jian Hu Mar 2011

Propeller: A Scalable Metadata Organization For A Versatile Searchable File System, Lei Xu, Hong Jiang, Xue Liu, Lei Tian, Yu Hua, Jian Hu

School of Computing: Technical Reports

The exponentially increasing amount of data in file systems has made it increasingly important for users, administrators and applications to be able to fast retrieve files using file-search services, instead of replying on the standard file system API to traverse the hierarchical namespaces.  The quality of the file-search services  is significantly affected by the file-indexing overhead, the file-search performance and the accuracy of search results.  Unfortunately, the existing file-search solutions either are so poorly scalable that their performance degrades unacceptably when the systems scale up, or incur so much crawling delays that they produce acceptably inaccurate results.  We believe that …


Spear Phishing Attack Detection, David T. Merritt Mar 2011

Spear Phishing Attack Detection, David T. Merritt

Theses and Dissertations

This thesis addresses the problem of identifying email spear phishing attacks, which are indicative of cyber espionage. Spear phishing consists of targeted emails sent to entice a victim to open a malicious file attachment or click on a malicious link that leads to a compromise of their computer. Current detection methods fail to detect emails of this kind consistently. The SPEar phishing Attack Detection system (SPEAD) is developed to analyze all incoming emails on a network for the presence of spear phishing attacks. SPEAD analyzes the following file types: Windows Portable Executable and Common Object File Format (PE/COFF), Adobe Reader, …


Reactive Routing In Hidra Networks, Scott Michael Marshall Mar 2011

Reactive Routing In Hidra Networks, Scott Michael Marshall

Computer Engineering

In recent years, the Internet has grown so large that the future scalability of the Internet has become a major concern. The two primary scalability concerns are the size of the forwarding table and the ability for BGP to converge while distributing hundreds of thousands of routes.

HIDRA is a new Internet routing architecture that is backwards-compatible with existing routing technologies and protocols that focuses on feasibility-of-implementation. HIDRA remedies the first Internet scalability concern by proposing a means to reduce the number of entries in the default-free zone (DFZ) forwarding table.

This project extends HIDRA by designing a complete reactive …


Self-Stabilizing Leader Election In Dynamic Networks, Hema Piniganti Dec 2010

Self-Stabilizing Leader Election In Dynamic Networks, Hema Piniganti

UNLV Theses, Dissertations, Professional Papers, and Capstones

The leader election problem is one of the fundamental problems in distributed computing. It has applications in almost every domain. In dynamic networks, topology is expected to change frequently. An algorithm A is self-stabilizing if, starting from a completely arbitrary configuration, the network will eventually reach a legitimate configuration.

Note that any self-stabilizing algorithm for the leader election problem is also an algorithm for the dynamic leader election problem, since when the topology of the network changes, we can consider that the algorithm is starting over again from an arbitrary state. There are a number of such algorithms in the …


Dynamic Distributed Programming And Applications To Swap Edge Problem, Feven Z. Andemeskel Dec 2010

Dynamic Distributed Programming And Applications To Swap Edge Problem, Feven Z. Andemeskel

UNLV Theses, Dissertations, Professional Papers, and Capstones

Link failure is a common reason for disruption in communication networks. If communication between processes of a weighted distributed network is maintained by a spanning tree T, and if one edge e of T fails, communication can be restored by finding a new spanning tree, T’. If the network is 2-edge connected, T’ can always be constructed by replacing e by a single edge, e’, of the network. We refer to e’ as a swap edge of e.


The best swap edge problem is to find the best choice of e’, that is, that e which causes the new spanning …


Hidra: Hierarchical Inter-Domain Routing Architecture, Bryan Clevenger May 2010

Hidra: Hierarchical Inter-Domain Routing Architecture, Bryan Clevenger

Master's Theses

As the Internet continues to expand, the global default-free zone (DFZ) forwarding table has begun to grow faster than hardware can economically keep pace with. Various policies are in place to mitigate this growth rate, but current projections indicate policy alone is inadequate. As such, a number of technical solutions have been proposed. This work builds on many of these proposed solutions, and furthers the debate surrounding the resolution to this problem. It discusses several design decisions necessary to any proposed solution, and based on these tradeoffs it proposes a Hierarchical Inter-Domain Routing Architecture - HIDRA, a comprehensive architecture with …


A Genetic Algorithm Approach For Optimized Routing, Pavithra Gudur Apr 2010

A Genetic Algorithm Approach For Optimized Routing, Pavithra Gudur

Electrical & Computer Engineering Theses & Dissertations

Genetic Algorithms find several applications in a variety of fields, such as engineering, management, finance, chemistry, scheduling, data mining and so on, where optimization plays a key role. This technique represents a numerical optimization technique that is modeled after the natural process of selection based on the Darwinian principle of evolution. The Genetic Algorithm (GA) is one among several optimization techniques and attempts to obtain the desired solution by generating a set of possible candidate solutions or populations. These populations are then compared and the best solutions from the set are retained. Subsequently, new candidate solutions are produced, and the …


Development Of A Methodology For Customizing Insider Threat Auditing On A Linux Operating System, William T. Bai Mar 2010

Development Of A Methodology For Customizing Insider Threat Auditing On A Linux Operating System, William T. Bai

Theses and Dissertations

Insider threats can pose a great risk to organizations and by their very nature are difficult to protect against. Auditing and system logging are capabilities present in most operating systems and can be used for detecting insider activity. However, current auditing methods are typically applied in a haphazard way, if at all, and are not conducive to contributing to an effective insider threat security policy. This research develops a methodology for designing a customized auditing and logging template for a Linux operating system. An intent-based insider threat risk assessment methodology is presented to create use case scenarios tailored to address …


A Distributed Network Logging Topology, Nicholas E. Fritts Mar 2010

A Distributed Network Logging Topology, Nicholas E. Fritts

Theses and Dissertations

Network logging is used to monitor computer systems for potential problems and threats by network administrators. Research has found that the more logging enabled, the more potential threats can be detected in the logs (Levoy, 2006). However, generally it is considered too costly to dedicate the manpower required to analyze the amount of logging data that it is possible to generate. Current research is working on different correlation and parsing techniques to help filter the data, but these methods function by having all of the data dumped in to a central repository. Central repositories are limited in the amount of …


Visually Managing Ipsec, Peter J. Dell'accio Mar 2010

Visually Managing Ipsec, Peter J. Dell'accio

Theses and Dissertations

The United States Air Force relies heavily on computer networks to transmit vast amounts of information throughout its organizations and with agencies throughout the Department of Defense. The data take many forms, utilize different protocols, and originate from various platforms and applications. It is not practical to apply security measures specific to individual applications, platforms, and protocols. Internet Protocol Security (IPsec) is a set of protocols designed to secure data traveling over IP networks, including the Internet. By applying security at the network layer of communications, data packets can be secured regardless of what application generated the data or which …


A Self-Organizing Neural Architecture Integrating Desire, Intention And Reinforcement Learning, Ah-Hwee Tan, Yu-Hong Feng, Yew-Soon Ong Mar 2010

A Self-Organizing Neural Architecture Integrating Desire, Intention And Reinforcement Learning, Ah-Hwee Tan, Yu-Hong Feng, Yew-Soon Ong

Research Collection School Of Computing and Information Systems

This paper presents a self-organizing neural architecture that integrates the features of belief, desire, and intention (BDI) systems with reinforcement learning. Based on fusion Adaptive Resonance Theory (fusion ART), the proposed architecture provides a unified treatment for both intentional and reactive cognitive functionalities. Operating with a sense-act-learn paradigm, the low level reactive module is a fusion ART network that learns action and value policies across the sensory, motor, and feedback channels. During performance, the actions executed by the reactive module are tracked by a high level intention module (also a fusion ART network) that learns to associate sequences of actions …


A Neural Network Approach To Border Gateway Protocol Peer Failure Detection And Prediction, Cory B. White Dec 2009

A Neural Network Approach To Border Gateway Protocol Peer Failure Detection And Prediction, Cory B. White

Master's Theses

The size and speed of computer networks continue to expand at a rapid pace, as do the corresponding errors, failures, and faults inherent within such extensive networks. This thesis introduces a novel approach to interface Border Gateway Protocol (BGP) computer networks with neural networks to learn the precursor connectivity patterns that emerge prior to a node failure. Details of the design and construction of a framework that utilizes neural networks to learn and monitor BGP connection states as a means of detecting and predicting BGP peer node failure are presented. Moreover, this framework is used to monitor a BGP network …


Wireless Networks: Spert: A Stateless Protocol For Energy-Sensitive Real-Time Routing For Wireless Sensor Network, Sohail Jabbar, Abid Ali Minhas, Raja Adeel Akhtar Aug 2009

Wireless Networks: Spert: A Stateless Protocol For Energy-Sensitive Real-Time Routing For Wireless Sensor Network, Sohail Jabbar, Abid Ali Minhas, Raja Adeel Akhtar

International Conference on Information and Communication Technologies

Putting constraints on performance of a system in the temporal domain, some times turns right into wrong and update into outdate. These are the scenarios where apposite value of time inveterate in the reality. But such timing precision not only requires tightly scheduled performance constraints but also requires optimal design and operation of all system components. Any malfunctioning at any relevant aspect may causes a serious disaster and even loss of human lives. Managing and interacting with such real-time system becomes much intricate when the resources are limited as in wireless sensor nodes. A wireless sensor node is typically comprises …


Wireless Networks: Automated Frequency Distribution, Management & Assignment (Afdma) In Ieee 802.16, Khurram Shehzad, A. Ali, F. Rasool, R. M. Hashmi, A. Zubair, R. L. Ali Aug 2009

Wireless Networks: Automated Frequency Distribution, Management & Assignment (Afdma) In Ieee 802.16, Khurram Shehzad, A. Ali, F. Rasool, R. M. Hashmi, A. Zubair, R. L. Ali

International Conference on Information and Communication Technologies

Frequency is amongst the most exclusive and most costly resources in wireless communication networks, especially, while considering the demands of broadband wireless access (BWA). In BWA, the management of frequency distribution and its effective utilization is of utmost importance. This research explores possible ways to ensure the most effective allocation of bandwidth resources and their best possible utilization on need basis. The model for static frequency allocation has been optimized and the dynamic frequency management has been calculated while dividing the users in different user classes on the basis of their needs and requirements. The effect of ping-pong handovers has …


Application Of Ict - I: Using Point-To-Point 1550nm Laser For Outdoor Mobility, Roshan A. Shaikh, Abdul Basit Aug 2009

Application Of Ict - I: Using Point-To-Point 1550nm Laser For Outdoor Mobility, Roshan A. Shaikh, Abdul Basit

International Conference on Information and Communication Technologies

Significant implementation challenges exist in wireless backbone connectivity. Typical optical wireless communication topologies are evaluated. A fresh approach using 1550nm Wavelength laser to design protocol and topology for point-to-point outdoor connectivity is carried out. Matlab simulation results support the 1550nm laser as a good choice for outdoor connectivity for optical wireless communication. New design and topology for an optical wireless communication system is suggested with special consideration of security and recommendation for the optimal use of such a technology is suggested.


Networks - I: Networks-On-Chip: Challenges, Trends And Mechanisms For Enhancements, Omer Tayan Aug 2009

Networks - I: Networks-On-Chip: Challenges, Trends And Mechanisms For Enhancements, Omer Tayan

International Conference on Information and Communication Technologies

The rate of increase of silicon capacity in integrated circuits (IC) will enable system integration of several billion transistors to reside on a single chip in the near future. Future system-on-chip (SoC) systems must therefore integrate up to several hundreds of cores within a single chip, and SoC designs will employ on-chip communication networks (NoCs) as a result. This paper discusses the problems with many current SoC systems, surveys the challenges and trends facing future SoC designs and proposes a mechanism for enhancing NoC strategies of the future by enhancing memory management and utilization techniques within an NoC.


Networks - I: A Comparative Analysis Of Dccp Variants (Ccid2, Ccid3), Tcp And Udp For Mpeg4 Video Applications, Muhammad Ajmal Azad, Rashid Mahmood, Tahir Mehmood Aug 2009

Networks - I: A Comparative Analysis Of Dccp Variants (Ccid2, Ccid3), Tcp And Udp For Mpeg4 Video Applications, Muhammad Ajmal Azad, Rashid Mahmood, Tahir Mehmood

International Conference on Information and Communication Technologies

New emerging technologies like Multimedia applications require timely delivery of information as compared to reliability. The most widely used protocols over transport layer are Transmission Control Protocol (TCP) and User Datagram Protocol (UDP). Both of these have some drawbacks while using in real time applications. TCP increases delay in transfer of data but achieving reliable transfer of data while UDP does not provide any acknowledgment, hence it overcomes the problem of delay but lacking congestion control mechanism. To provide congestion control over transport layer using UDP, Datagram Congestion Control Protocol (DCCP) has been designed to provide timely delivery of data …


Artificial Intelligence – I: A Two-Step Approach For Improving Efficiency Of Feedforward Multilayer Perceptrons Network, Shoukat Ullah, Zakia Hussain Aug 2009

Artificial Intelligence – I: A Two-Step Approach For Improving Efficiency Of Feedforward Multilayer Perceptrons Network, Shoukat Ullah, Zakia Hussain

International Conference on Information and Communication Technologies

An artificial neural network has got greater importance in the field of data mining. Although it may have complex structure, long training time, and uneasily understandable representation of results, neural network has high accuracy and is preferable in data mining. This research paper is aimed to improve efficiency and to provide accurate results on the basis of same behaviour data. To achieve these objectives, an algorithm is proposed that uses two data mining techniques, that is, attribute selection method and cluster analysis. The algorithm works by applying attribute selection method to eliminate irrelevant attributes, so that input dimensionality is reduced …


Virtual Wired Transmission Scheme - A Novel Technique For Efficient Mobile Adhoc Networks, Manikya Vinay Rali Jul 2009

Virtual Wired Transmission Scheme - A Novel Technique For Efficient Mobile Adhoc Networks, Manikya Vinay Rali

Electrical & Computer Engineering Theses & Dissertations

This thesis proposes a method called virtual wired transmission scheme for ad hoc networks. The scheme is an efficient method to improve network performance parameters such as energy efficiency, capacity, interference, network throughput, etc. Performance parameters improvement can be done at different layers of the network architecture for mobile ad hoc networks. However most of the research efforts are concentrated on Physical, MAC and Network layers. In this thesis, a MAC protocol with a major MAC layer modification is proposed in combination with the usage of directional antennas, developing a novel method called virtual wired transmission scheme. In virtual wired …


Store And Forward Routing For Sparse Pico-Satellite Sensor Networks With Data-Mules, Trevor Joseph Koritza Jun 2009

Store And Forward Routing For Sparse Pico-Satellite Sensor Networks With Data-Mules, Trevor Joseph Koritza

Master's Theses

Satellites are playing an increasingly important role in collecting scientific information, providing communication services, and revolutionizing navigation. Until recently satellites were large and very expensive, creating a high barrier to entry that only large corporations and government agencies could overcome. In the past few years the CubeSat project at California Polytechnic University in San Luis Obispo (Cal Poly) has worked to refine the design and launching of small, lightweight, and less expensive satellites called pico-satellites, opening space up to a wider audience. Now that Cal Poly has the launch logistics and hardware under control, a new problem has arisen. These …


A Hidden Markov Model Based Approach To Detect Rogue Access Points, Gayathri Shivaraj Apr 2009

A Hidden Markov Model Based Approach To Detect Rogue Access Points, Gayathri Shivaraj

Electrical & Computer Engineering Theses & Dissertations

One of the most challenging security concerns for network administrators is the presence of Rogue access points. The challenge is to detect and disable a Rogue access point before it can cause hazardous damage to the network. This thesis proposes a statistically based approach to detect Rogue access points using a Hidden Markov Model, which is applied to passively measure packet-header data collected at a gateway router or any monitoring point. This approach utilizes variations in packet inter-arrival time to differentiate between authorized access points and Rouge access points. This approach used the inter-arrival time of a packet as a …


Dynamic Network Formation Using Ant Colony Optimization, Steven C. Oimoen Mar 2009

Dynamic Network Formation Using Ant Colony Optimization, Steven C. Oimoen

Theses and Dissertations

Military and industry are moving toward every device being network enabled and connected for reliable availability of communication and information. To make this type of system a reality, the devices must be capable of forming a network topology on their own in a dynamic environment to ensure that the correct information reaches a desired location and on-time. This research presents three contributions for solving highly dynamic (i.e. drastic change within the network) Multi-commodity Capacitated Network Design Problems (MCNDPs) resulting in a distributed multi-agent network design algorithm. The first contribution incorporates an Ant Colony Optimization (ACO) algorithm Ant Colony System (ACS) …


Using Predictive Rendering As A Vision-Aided Technique For Autonomous Aerial Refueling, Adam D. Weaver Mar 2009

Using Predictive Rendering As A Vision-Aided Technique For Autonomous Aerial Refueling, Adam D. Weaver

Theses and Dissertations

This research effort seeks to characterize a vision-aided approach for an Unmanned Aerial System (UAS) to autonomously determine relative position to another aircraft in a formation, specifically to address the autonomous aerial refueling problem. A system consisting of a monocular digital camera coupled with inertial sensors onboard the UAS is analyzed for feasibility of using this vision-aided approach. A three-dimensional rendering of the tanker aircraft is used to generate predicted images of the tanker as seen by the receiver aircraft. A rigorous error model is developed to model the relative dynamics between an INS-equipped receiver and the tanker aircraft. A …


The Impact Of Communication Medium On Team Performance Patterns, Pilar Pazos, Mario G. Beruvides Jan 2009

The Impact Of Communication Medium On Team Performance Patterns, Pilar Pazos, Mario G. Beruvides

Engineering Management & Systems Engineering Faculty Publications

The increased impact of globalization and rapidly changing technologies are some of the biggest challenges facing 21st century organizations. Remote teams supported through computer-based systems have been identified as a key lever to help organizations adapt to this turbulent environment. This study sheds some light on how teams perform and adapt by evaluating performance and synergy over time for teams in two different settings: computer supported and face-to-face. Participants in the study were randomly assigned either to a computer-supported or a face-to face group. Each group met over three sessions to perform a series of tasks that were evaluated using …


Dynamic Adaptation Of Joint Transmission Power And Contention Window In Vanet, Danda B. Rawat, Gongjun Yan, Dimitrie C. Popescu, Michele C. Weigle, Stephan Olariu Jan 2009

Dynamic Adaptation Of Joint Transmission Power And Contention Window In Vanet, Danda B. Rawat, Gongjun Yan, Dimitrie C. Popescu, Michele C. Weigle, Stephan Olariu

Electrical & Computer Engineering Faculty Publications

In this paper, we propose an algorithm for joint adaptation of transmission power and contention window to improve the performance of vehicular network in a cross layer approach. The high mobility of vehicles in vehicular communication results in the change in topology of the Vehicular Ad-hoc Network (VANET) dynamically, and the communication link between two vehicles might remain active only for short duration of time. In order for VANET to make a connection for long time and to mitigate adverse effects due to high and fixed transmission power, the proposed algorithm adapts transmission power dynamically based on estimated local traffic …


Extending The Network Life Time In Wsn Using Energy Efficient Algorithm, Venkata Sesha Sai Koundinya Goparaju Jul 2008

Extending The Network Life Time In Wsn Using Energy Efficient Algorithm, Venkata Sesha Sai Koundinya Goparaju

Electrical & Computer Engineering Theses & Dissertations

Wireless Sensor networks have many potential applications. These wireless sensor networks necessitate specific design requirements of which energy efficiency is vital. The sensor networks consist of sensor nodes that operate on battery power, and replacement of these batteries is very often a strenuous task, since networks are deployed in areas where the act of replacing the batteries proves impractical.

With the limited available energy of sensor nodes, most of the energy is drained during communication. An energy efficient routing algorithm can prolong the lifetime of the network by gradually depleting the nodes in the network. Many of the routing protocols …