No description available.

Thesis (Ph.D.) - Carleton University, 2006. / Includes bibliographical references (p. 139-144). Also available in electronic format on the Internet.

Thesis (M.S.)--University of Alabama at Birmingham, 2008. / Description based on contents viewed Oct. 7, 2008; title from PDF t.p. Includes bibliographical references (p. 80-81).

Thesis (MScEng)--University of Stellenbosch, 2003. / ENGLISH ABSTRACT: The Linux operating system and shared Ethernet are alternative technologies with the potential to reduce both the development time and costs of satellites as well as the supporting infrastructure. Modular satellites, ground stations and rapid proto typing testbeds also have a common requirement for distributed real-time computation. The identified technologies were investigated to determine whether this requirement could also be met. Various real-time extensions and modifications are currently available for the Linux operating system. A suitable open source real-time extension called Real-Time Application Interface (RTAI) was selected for the implementation of an experimental distributed real-time system. Experimental results showed that the RTAI operating system could deliver deterministic realtime performance, but only in the absence of non-real-time load. Shared Ethernet is currently the most popular and widely used commercial networking technology. However, Ethernet wasn't developed to provide real-time performance. Several methods have been proposed in literature to modify Ethernet for real-time communications. A token passing protocol was found to be an effective and least intrusive solution. The Real-Time Token (RTToken) protocol was designed to guarantee predictable network access to communicating real-time tasks. The protocol passes a token between nodes in a predetermined order and nodes are assigned fixed token holding times. Experimental results proved that the protocol offered predictable network access with bounded jitter. An experimental distributed real-time system was implemented, which included the extension of the RTAI operating system with the RTToken protocol, as a loadable kernel module. Real-time tasks communicated using connectionless Internet protocols. The Real-Time networking (RTnet) subsystem of RTAI supported these protocols. Under collision-free conditions consistent transmission delays with bounded jitter was measured. The integrated RTToken protocol provided guaranteed and bounded network access to communicating real-time tasks, with limit overheads. Tests exhibited errors in some of the RTAI functionality. Overall the investigated technologies showed promise in being able to meet the distributed real-time requirements of various applications, including those found in the satellite environment. / AFRIKAANSE OPSOMMING: Die Linux bedryfstelsel en gedeelde Ethernet is geïdentifiseer as potensiële tegnologieë vir satelliet bedryf wat besparings in koste en vinniger ontwikkeling te weeg kan bring. Modulêr ontwerpte satelliete, grondstasies en ontwikkeling platforms het 'n gemeenskaplike behoefte vir verspreide intydse verwerking. Verskillende tegnologieë is ondersoek om te bepaal of aan die vereiste ook voldoen kan word. Verskeie intydse uitbreidings en modifikasies is huidiglik beskikbaar vir die Linux bedryfstelsel. Die "Real-Time Application Interface" (RTAI) bedryfstelsel is geïdentifiseer as 'n geskikte intydse uitbreiding vir die implementering van 'n eksperimentele verspreide intydse stelsel. Eksperimentele resultate het getoon dat die RTAI bedryfstelsel deterministies en intyds kan opereer, maar dan moet dit geskied in die afwesigheid van 'n nie-intydse verwerkingslas. Gedeelde Ethernet is 'n kommersiële network tegnologie wat tans algemeen beskikbaar is. Die tegnologie is egter nie ontwerp vir intydse uitvoering nie. Verskeie metodes is in die literatuur voorgestelom Ethernet te modifiseer vir intydse kommunikasie. Hierdie ondersoek het getoon dat 'n teken-aangee protokol die mees effektiewe oplossing is en waarvan die implementering min inbreuk maak. Die "Real-Time Token" (RTToken) protokol is ontwerp om voorspelbare netwerk toegang tot kommunikerende intydse take te verseker. Die protokol stuur 'n teken tussen nodusse in 'n voorafbepaalde volgorde. Nodusse word ook vaste teken hou-tye geallokeer. Eksperimentele resultate het aangedui dat die protokol deterministiese netwerk toegang kan verseker met begrensde variasies. 'n Eksperimentele verspreide intydse stelsel is geïmplementeer. Dit het ingesluit die uitbreiding van die RTAI bedryfstelsel met die RTToken protokol; verpak as 'n laaibare bedryfstelsel module. Intydse take kan kommunikeer met verbindinglose protokolle wat deur die "Real-Time networking" (RTnet) substelsel van RTAI ondersteun word. Onder ideale toestande is konstante transmissie vertragings met begrensde variasies gemeet. Die integrasie van die RTToken protokol het botsinglose netwerk toegang aan kommunikerende take verseker, met beperkte oorhoofse koste as teenprestasie. Eksperimente het enkele foute in die funksionaliteit van RTAI uitgewys. In die algemeen het die voorgestelde tegnologieë getoon dat dit potensiaal het vir verskeie verspreide intydse toepassings in toekomstige satelliet en ook ander omgewings.

Every environment is susceptible to risks and Wireless Local Area Networks (WLANs) based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard are no exception. The most apparent risk of WLANs is the ease with which itinerant intruders obtain illicit entry into these networks. These intrusion security risks must therefore be addressed which means that information security risk analysis and risk management need to be considered as integral elements of the organisation’s business plan. A well-established qualitative risk analysis and risk management methodology, the Operationally Critical Threat Asset and Vulnerability Evaluation (OCTAVE) is selected for conducting the WLAN intrusion security risk analysis and risk management process. However, the OCTAVE risk analysis methodology is beset with a number of problems that could hamper a successful WLAN intrusion security risk analysis. The ultimate deliverable of this qualitative risk analysis methodology is the creation of an organisation-wide protection strategy and risk mitigation plan. Achieving this end using the OCTAVE risk analysis methodology requires an inordinate amount of time, ranging from months to years. Since WLANs are persistently under attack, there is a dire need for an expeditious risk analysis methodology. Furthermore, the OCTAVE risk analysis methodology stipulates the identification of assets and corresponding threat scenarios via a brainstorming session, which may be beyond the scope of a person who is not proficient in information security issues. This research was therefore inspired by the pivotal need for a risk analysis and risk management methodology to address WLAN intrusion attacks and the resulting risks they pose to the confidentiality, integrity and availability of information processed by these networks. Copyright / Dissertation (MSc (Computer Science))--University of Pretoria, 2006. / Computer Science / unrestricted

京都大学 / 0048 / 新制・課程博士 / 博士(情報学) / 甲第20031号 / 情博第626号 / 新制||情||109(附属図書館) / 33127 / 京都大学大学院情報学研究科通信情報システム専攻 / (主査)教授 守倉 正博, 教授 原田 博司, 教授 梅野 健 / 学位規則第4条第1項該当 / Doctor of Informatics / Kyoto University / DGAM

International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California / The necessity to acquire and analyze data dates back to the beginning of science itself. Long ago, a scientist may have run experiments and noted the results on a piece of paper. These notes became the data. The method was crude, but effective. As experiments got more complex, the need for better methodologies arose. Scientists began using computers to gather, analyze, and store the data. This method worked well for most types of data acquisition. As the amount of data being collected increased, larger computers, faster processors, and faster storage devices were used in order to keep up with the demand. This method was more refined, but still did not meet the needs of the scientific community. Requirements began to change in the data acquisition arena. More people wanted access to the data in real time. Companies producing large data acquisition systems began to move toward a network-based solution. This architecture featured a specialized computer called the server, which contained all of the data acquisition hardware. The server handled requests from multiple clients and handled the data flow to the network, data displays, and the archive medium. While this solution worked well to satisfy most requirements, it fell short in meeting others. The ability to have multiple computers working together across a local or wide area network (LAN or WAN) was not addressed. In addition, this architecture inherently had a single point of failure. If the server machine went down, all data from all sources was lost. Today, we see that the requirements for data acquisition systems include features only dreamed of five years ago. These new systems are linked around the world by wide area networks. They may include code to command satellites or handle 250 Mbps download rates. They must produce data for dozens of users at once, be customizable by the end user, and they must run on personal computers (PCs)! Systems like these cannot work using the traditional client/server model of the past. The data acquisition industry demands systems with far more features than were traditionally available. These systems must provide more reliability and interoperability, and be available at a fraction of the cost. To this end, we must use commercial-off-the-shelf (COTS) computers that operate faster than the mainframe computers of only a decade ago. These computers must run software that is smart, reliable, scalable, and easy to use. All of these requirements can be met by a network of PCs running the Windows NT operating system.

Approved for public release; distribution in unlimited. / In spite of the fact that wireless network technology has been available for long period of time, there has been very limited wireless networks deployments around the world before 1997 due to the lack of widely recognized standard for wireless networks. Thanks to the approval of the IEEE 802.11 family of standards in 1997, the world has witnessed tremendous deployment and proliferation of wireless networks in all aspects of life. Although the IEEE 802.11 family of standards has been ratified to design radio transceivers for wireless computer stations capable of interconnecting with other wireless computer stations in close proximity, the technology has been successfully employed to design and implement wireless networks with great number of distant wireless computer stations with reasonable data throughput and flexibility. This thesis explores the wireless network technology and the primary building blocks and components of a wireless network. It also explores the IEEE 802.11 standard and its technical specifications including the Physical layer (PHY), the Media Access Control layer (MAC) and the ongoing task forces. Additionally, the thesis examines the wireless network security including the vulnerabilities, ongoing improvements and recommendations. Next, it investigates the market for available wireless devices compatible with the IEEE 802.11 standard that can be used to build a wireless network with high data throughput and high level of security. Subsequently, the thesis formulates a design plan for civilian wireless network with different scenarios in order to provide a speedy solution to the limited broadband service availability in the Sultanate of Oman. Additionally, the thesis formulates a generic design plan for a military wireless network with different scenarios that can be rapidly deployed in the field of operations. / Computer Engineer, Royal Army of Oman

Approved for public release, distribution is unlimited / This thesis sought to design and implement a low-cost, portable, Free-Space Optics (FSO) communications device for Ethernet applications. Under some circumstances such a device would have utility at a Combat Operations Center (COC), a Field Artillery Position, or wherever else fiber optic cable is used in garrison or field. The design was based on commercial off the shelf components originally designed for fiber optic applications. Based on a 155 megabits per second (Mbps) media converter, the design used two fiber optic transceivers, coupled to collimating lenses to pass data over free-space. Sustained data rate of 100 Mbps was achieved with full network functionality on the optical bench with a low-power (0.5mW) laser diode transmitter without focusing optics on the receiver. The laser diode power(mounted on device), was measured with acceptable losses up to 300 ft during testing using a photodiode with focusing optics. The findings indicate that the system with proper collecting optics could be optimized for free-space communication at short to moderate ranges. / Captain, United States Marine Corps

Submitted by Mariana Dornelles Vargas (marianadv) on 2015-03-24T14:39:54Z No. of bitstreams: 1 lp2p.pdf: 907325 bytes, checksum: f14a60879bfa80f3f2b600d16e6b6d0f (MD5) / Made available in DSpace on 2015-03-24T14:39:54Z (GMT). No. of bitstreams: 1 lp2p.pdf: 907325 bytes, checksum: f14a60879bfa80f3f2b600d16e6b6d0f (MD5) Previous issue date: 2011-03-30 / Nenhuma / Nos últimos anos, o crescimento da Internet e o surgimento de novos serviços em rede contribuíram para o desenvolvimento de várias arquiteturas destinadas à computação distribuída. Neste contexto, a tecnologia P2P tem fomentado o interesse da comunidade científica em decorrência de suas características e funcionalidades inovadoras. Um dos fatores responsáveis por esta popularidade é proveniente das aplicações destinadas ao compartilhamento de arquivos. Este serviço também ocorre de forma expressiva em redes de menor abrangência (ex. LANs), onde recursos presentes nas estações de trabalho são muitas vezes desperdiçados enquanto as corporações investem maciçamente em infraestrutura específica para prover este serviço. Uma possível alternativa frente a este cenário, está na adaptação de alguns conceitos do paradigma P2P à infraestrutura de rede local. No entanto, há poucos esforços no sentido de explorar o potencial da comunicação peer-to-peer aliada aos padrões e vantagens disponíveis nas LANs. Em virtude de sua natureza distribuída, as abordagens P2P convencionais adotam este sistema principalmente em redes de longa distância (MANs e WANs) para formação da estrutura overlay. Contudo, estes aspectos não inviabilizam a utilização de algumas técnicas e características da tecnologia P2P em redes de menor abrangência. Este conjunto de fatores motivaram a proposta do LP2P-Local Peer-to-Peer-Protocol-, uma plataforma de comunicação distribuída e descentralizada que aplica a tecnologia P2P no compartilhamento de arquivos em redes locais. / In recent years, the growth of the Internet and the emergence of new network services contributed to the development of various architectures for distributed computing. In this context, P2P technology has fostered the interest of the scientific community due to its features and innovative characteristies. One of the factors responsible for this popularity is coming from consumer applications and file sharing. This service also occurs in a significant way into networks of smaller scope (e.g. LANs), where features present in the workstations are often wasted while corporations invest heavily in infrastructure to provide this particular service. A possible alternative in the face of this scenario is the adaptation of some concepts of P2P paradigm to the local network infrastructure. However, there are few efforts to explore the potential of communication peer-to-peer coupled with the patterns and advantages available in LANs. Due to its distributed nature, conventional P2P approaches adopted this system mainly in long distance (MANs and WANs) to overlay structure formation. However, these aspects do not make use of some techniques and features of P2P networks smaller. These factors motivated the proposal of LP2P-Local Peer-to-Peer-Protocol- a distributed communications platform that applies technology in P2P file sharing on local networks.