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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Laboratorní úlohy v prostředí NS3 pro předmět Pokročilé komunikační techniky / Laboratory exercises in NS3 enviroment for Advanced communication technology course

Vadkerti, Gabriel January 2015 (has links)
This master thesis deals with creating laboratory exercises for students in simulator NS-3, where the IPv4 and IPv6 protocols, unicast and multicast transmission types, quality of services in wireless networks, furthermore protocols TCP and UDP are analyzed. The first section describes the NS-3 network simulator, the Eclipse development environment and the method how to connect them. In the next section protocols IPv4 and IPv6 are presented, the structure of the headers and the technique of fragmentation are described in detail. Based on this a laboratory exercise is created which deals with comparison of protocols IPv4 and IPv6. In the next section the types of transmissions are described, furthermore the multicast transmission type is explained more in detail. In the next practical section the second laboratory exercise is created, which deals with comparison of unicast and multicast transmission types. The subject of the following section is ensuring quality of services in data networks, the EDCA access method is discussed more in detail. In the next section the EDCA access method is implemented in a simulation as a laboratory exercise, in which the impact of the access category of EDCA to different transmission parameters is investigated. The next section deals with protocols TCP and UDP, furthermore with the structure of their headers. In the last section a laboratory exercise is created, in which the properties of the protocols TCP and UDP are compared.
22

Study of the StpA protein from Salmonella typhimurium and Escherichia coli

Sonnenfield, Jean Marie January 1997 (has links)
No description available.
23

Ungleichwertigkeitsideen als Schrittmacher der NS-„Euthanasie“ / Notions of inequality as catalysts for NS euthanasia

Henke, Klaus-Dietmar 07 November 2008 (has links) (PDF)
Der Beitrag beleuchtet verschiedene vornationalsozialistische Denkmuster in Eugenik und Psychiatrie als Schrittmacher wissenschaftlicher Entmenschlichung und politischer Massentötung nach 1933. / The article discusses various pre-National Socialist paradigms in eugenics and psychiatry in their role as catalysts for scientific dehumanisation and political mass homicide after 1933.
24

Power characterisation of a Zigbee wireless network in a real time monitoring application

Prince-Pike, Arrian January 2009 (has links)
Zigbee is a relatively new wireless mesh networking standard with emphasis on low cost and energy conservation. It is intended to be used in wireless monitoring and control applications such as sensors and remotely operated switches where the end devices are battery powered. Because it is a recent technology there is not sufficient understanding on how network architecture and configuration affect power consumption of the battery powered devices. This research investigates the power consumption and delivery ratio of Zigbee wireless mesh and star networks for a single sink real time monitoring system at varying traffic rates and the beacon and non beacon mode operation of its underlying standard IEEE 802.15.4 in the star network architecture. To evaluate the performance of Zigbee, the network operation was simulated using the simulation tool NS-2. NS-2 is capable of simulating the entire network operation including traffic generation and energy consumption of each node in the network. After first running the simulation it was obvious that there were problems in the configuration of the simulator as well as some unexpected behaviour. After performing several modifications to the simulator the results improved significantly. To validate the operation of the simulator and to give insight on the operation of Zigbee, a real Zigbee wireless network was constructed and the same experiments that were conducted on the simulator were repeated on the Zigbee network. The research showed that the modified simulator produced good results that were close to the experimental results. It was found that the non beacon mode of operation had the lowest power consumption and best delivery ratio at all tested traffic rates. The operation of Zigbee mesh and star networks were compared to the results for IEEE 802.15.4 star networks in non beacon mode which revealed that the extra routing traffic sent by the Zigbee networking layers does contribute significantly to the power consumption, however even with the extra routing traffic, power consumption is still so low that it the battery life of the device would be limited by the shelf life of the battery, not by the energy consumption of the device. This research has successfully achieved its objectives and identified areas for future development. The simulator model for NS-2 could be improved to further increase the accuracy of the results as well as include the Zigbee routing layers and the experimental results could be improved by a more accurate power consumption data acquisition method.
25

Power characterisation of a Zigbee wireless network in a real time monitoring application

Prince-Pike, Arrian January 2009 (has links)
Zigbee is a relatively new wireless mesh networking standard with emphasis on low cost and energy conservation. It is intended to be used in wireless monitoring and control applications such as sensors and remotely operated switches where the end devices are battery powered. Because it is a recent technology there is not sufficient understanding on how network architecture and configuration affect power consumption of the battery powered devices. This research investigates the power consumption and delivery ratio of Zigbee wireless mesh and star networks for a single sink real time monitoring system at varying traffic rates and the beacon and non beacon mode operation of its underlying standard IEEE 802.15.4 in the star network architecture. To evaluate the performance of Zigbee, the network operation was simulated using the simulation tool NS-2. NS-2 is capable of simulating the entire network operation including traffic generation and energy consumption of each node in the network. After first running the simulation it was obvious that there were problems in the configuration of the simulator as well as some unexpected behaviour. After performing several modifications to the simulator the results improved significantly. To validate the operation of the simulator and to give insight on the operation of Zigbee, a real Zigbee wireless network was constructed and the same experiments that were conducted on the simulator were repeated on the Zigbee network. The research showed that the modified simulator produced good results that were close to the experimental results. It was found that the non beacon mode of operation had the lowest power consumption and best delivery ratio at all tested traffic rates. The operation of Zigbee mesh and star networks were compared to the results for IEEE 802.15.4 star networks in non beacon mode which revealed that the extra routing traffic sent by the Zigbee networking layers does contribute significantly to the power consumption, however even with the extra routing traffic, power consumption is still so low that it the battery life of the device would be limited by the shelf life of the battery, not by the energy consumption of the device. This research has successfully achieved its objectives and identified areas for future development. The simulator model for NS-2 could be improved to further increase the accuracy of the results as well as include the Zigbee routing layers and the experimental results could be improved by a more accurate power consumption data acquisition method.
26

HTR Heterogeneous Routing Protocol, um protocolo de roteamento para redes ad hoc heterogêneas

AMORIM, Rodrigo Diego Melo 31 January 2011 (has links)
Made available in DSpace on 2014-06-12T15:58:24Z (GMT). No. of bitstreams: 2 arquivo4095_1.pdf: 1892388 bytes, checksum: 36bca1d45a0d20795951c6d7db402746 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2011 / Faculdade de Amparo à Ciência e Tecnologia do Estado de Pernambuco / A popularidade de dispositivos móveis como meio de comunicação tem crescido nos últimos anos devido à facilidade de uso, custo e as mais variadas tecnologias. O aumento no número dessas opções como WiFi, Bluetooth ou até mesmo rede de telefonia móvel permitem uma maior conectividade desses dispositivos móveis na rede. Determinadas tarefas, como compartilhamento de stream de vídeo, implicam diferentes requisitos, o que pode requerer diferentes tecnologias de rede. Nos cenários de emergência, que incluem operações militares, força-tarefa para desastres e grupos de busca e resgate, onde se pressupõe a ausência de infraestrutura, o uso de redes sem fio e a permanente conectividade podem ser requisitos essenciais para realização de algumas tarefas. Para tanto o uso de um protocolo de roteamento que seja adequado a esse ambiente é de fundamental importância. Este trabalho faz um estudo comparativo de um novo protocolo de roteamento para redes heterogêneas ad hoc, chamado Heterogeneous Routing Protocol ou simplesmente HTR, focado em cenários de emergência, com um dos protocolos de roteamento para redes ad hoc mais usado, o OLSR. A fim de fazer uma análise robusta e escalável, o protocolo HTR foi implementado no simulador NS-3 e comparado ao OLSR através de métricas como taxa de entrega, atraso, pacotes perdidos, entre outros
27

Thellenyane batlabolela : tiragatso ya boitshwaro

Phala, Ragosebo Salome 03 January 2007 (has links)
Please read the abstract in the section 00front of this document / Dissertation (MA (Sepedi))--University of Pretoria, 2007. / African Languages / unrestricted
28

Analýza vehicular ad hoc sítě / Analysis of vehicular ad hoc network

Varmus, Pavol January 2019 (has links)
This diploma thesis aims to study VANET (vehicular ad hoc network), to describe the theory of this networks and describe attributes of these networks and to set the starting point for practical part. Thesis includes VANETs possibilities, its signal transportation and description of routing protocols. Another goal was to familiarize program NS-3 and set up simulation models in its interface. The main output of the practical part is program which simulates vehicle movement in Brno city and set the communication module which is adapted to fulfill the most realistic transmission capabilities. Practical part is divided to two parts. The goal of the first one was to simulate basic communication in theorized unrealistic scenario and the second part was the more realistic scenario. Overall, throughout the practical part was tested a variety of attributes, such as mobility models, standards, routing protocols and other parameters that provided diversity in final results. All the results, which consisted of summary of basic transmission capabilities and reclassification of the applicability of those technologies in real world, are discussed in the summary of the simulations output.
29

Návrh nových laboratorních úloh pro výuku principů komunikačních protokolů / Creation of new laboratory exercises explaining the principles of communication protocols

Babjarčiková, Lenka January 2021 (has links)
The aim of this master thesis is to create two laboratory exercises in ns-3 network simulator for chosen communication protocols. The chosen protocols are BGP and ICMPv6. The first part of this thesis contains teoretical knowledge used in order to design laboratory exercise. It contains descriptions of funcionality of both protocols and messages they use. This chapter also includes brief description of three options which were considered for implementation of BGP protocol into ns-3 enviroment. The second chapter consists of actual laboratory exercises which were created as a purpose of this thesis. Exercise for BGP protocol deals with creating neighborhoods between routers at autonomous system level, analyzing the way routers communicate within their neighborhoods and how protocol reacts when the connection between two neighbor routers fails. Exercise created for ICMPv6 protocol is focused on its messages and their usage within multiple protocol funcionalities, such as address configuration, link address resolution and error detection.
30

Network AIS-based DDoS attack detection in SDN environments with NS-3

Jevtic, Stefan G. 21 July 2017 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / With the ever increasing connectivity of and dependency on modern computing systems, our civilization is becoming ever more susceptible to cyberattack. To combat this, identifying and disrupting malicious traffic without human intervention becomes essential to protecting our most important systems. To accomplish this, three main tasks for an effective intrusion detection system have been identified: monitor network traffic, categorize and identify anomalous behavior in near real time, and take appropriate action against the identified threat. This system leverages distributed SDN architecture and the principles of Artificial Immune Systems and Self-Organizing Maps to build a network-based intrusion detection system capable of detecting and terminating DDoS attacks in progress.

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