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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.
1

Semantic-Based Context-Aware Service Discovery in Pervasive-Computing Environments

El-Sayed, Abdur-Rahman January 2006 (has links)
Recent technological advancements are enabling the vision of pervasive or ubiquitous computing to become a reality. Service discovery is vital in such a computing paradigm, where a great number of devices and software components collaborate unobtrusively and provide numerous services. Current service-discovery protocols do not make use of contextual information in discovering services, and as a result, fail to provide the most appropriate and relevant services for users. In addition, current protocols rely on keyword-based search techniques and do not consider the semantic description of services. Thus, they suffer from poor precision and recall. To address the need for a discovery architecture that supports the envisioned scenarios of pervasive computing, we propose a context-aware service-discovery protocol that exploits meaningful contextual information, either static or dynamic, to provide users with the most suitable and relevant services. The architecture relies on a shared, ontology-based, semantic representation of services and context to enhance precision and recall, and to enable knowledge sharing, capability-based search, autonomous reasoning, and semantic matchmaking. Furthermore, the architecture facilitates a dynamic service-selection mechanism to filter and rank matching services, based on their dynamic contextual attributes, which further enhances the discovery process and saves users time and effort. Our empirical results indicate the effectiveness and feasibility of the proposed architecture.
2

Semantic-Based Context-Aware Service Discovery in Pervasive-Computing Environments

El-Sayed, Abdur-Rahman January 2006 (has links)
Recent technological advancements are enabling the vision of pervasive or ubiquitous computing to become a reality. Service discovery is vital in such a computing paradigm, where a great number of devices and software components collaborate unobtrusively and provide numerous services. Current service-discovery protocols do not make use of contextual information in discovering services, and as a result, fail to provide the most appropriate and relevant services for users. In addition, current protocols rely on keyword-based search techniques and do not consider the semantic description of services. Thus, they suffer from poor precision and recall. To address the need for a discovery architecture that supports the envisioned scenarios of pervasive computing, we propose a context-aware service-discovery protocol that exploits meaningful contextual information, either static or dynamic, to provide users with the most suitable and relevant services. The architecture relies on a shared, ontology-based, semantic representation of services and context to enhance precision and recall, and to enable knowledge sharing, capability-based search, autonomous reasoning, and semantic matchmaking. Furthermore, the architecture facilitates a dynamic service-selection mechanism to filter and rank matching services, based on their dynamic contextual attributes, which further enhances the discovery process and saves users time and effort. Our empirical results indicate the effectiveness and feasibility of the proposed architecture.
3

A Secure Gateway Localization and Communication System for Vehicular Ad Hoc Networks

Wang, Yan 22 April 2013 (has links)
Intelligent Transport System (ITS) has become a hot research topic over the past decades. ITS is a system that applies the following technologies to the whole transportation management system efficiently, including information technique, wireless communication, sensor networks, control technique, and computer engineering. ITS provides an accurate, real time and synthetically efficient transportation management system. Obviously, Vehicular Ad Hoc NETworks (VANETs) attract growing attention from both the research community and industry all over the world. This is because a large amount of applications are enabled by VANETs, such as safety related applications, traffic management, commercial applications and general applications. When connecting to the internet or communicating with different networks in order to access a variety of services using VANETs, drivers and passengers in different cars need to be able to exchange messages with gateways from their vehicles. A secure gateway discovery process is therefore critical, because vehicles should not be subject to security attacks while they are communicating; however, currently there is no existing protocol focusing on secure gateway discovery. In this thesis, we first analyze and compare current existing secure service discovery protocols and then we propose a Secure Gateway Localization and Communication System for Vehicular Ad Hoc Networks (SEGAL), which concentrates on the security issue in gateway discovery. We focus on the authentication aspect by proposing secure cluster based VANETs, that can ensure the gateway discovery messages exchanged through secure clusters. We present the principle and specific process of our SEGAL protocol and analyze its performance to guarantee its outstanding practical applicability.
4

A Secure Gateway Localization and Communication System for Vehicular Ad Hoc Networks

Wang, Yan January 2013 (has links)
Intelligent Transport System (ITS) has become a hot research topic over the past decades. ITS is a system that applies the following technologies to the whole transportation management system efficiently, including information technique, wireless communication, sensor networks, control technique, and computer engineering. ITS provides an accurate, real time and synthetically efficient transportation management system. Obviously, Vehicular Ad Hoc NETworks (VANETs) attract growing attention from both the research community and industry all over the world. This is because a large amount of applications are enabled by VANETs, such as safety related applications, traffic management, commercial applications and general applications. When connecting to the internet or communicating with different networks in order to access a variety of services using VANETs, drivers and passengers in different cars need to be able to exchange messages with gateways from their vehicles. A secure gateway discovery process is therefore critical, because vehicles should not be subject to security attacks while they are communicating; however, currently there is no existing protocol focusing on secure gateway discovery. In this thesis, we first analyze and compare current existing secure service discovery protocols and then we propose a Secure Gateway Localization and Communication System for Vehicular Ad Hoc Networks (SEGAL), which concentrates on the security issue in gateway discovery. We focus on the authentication aspect by proposing secure cluster based VANETs, that can ensure the gateway discovery messages exchanged through secure clusters. We present the principle and specific process of our SEGAL protocol and analyze its performance to guarantee its outstanding practical applicability.
5

Service discovery for Personal Area Networks

Ayrault, Cécile January 2004 (has links)
With the increasing use of electronic devices, the need for affordable wireless services specifically context-aware services, in a so-called Personal Area Network (PAN) is becoming an area with significant potential. Service discovery is a basic function. Even though a number of service discovery protocols have been implemented, a specific protocol for a PAN environment may need to be developed, as the characteristics of a PANs differ from other networking environments. Thus, the specific requirements for service discovery from a PAN perspective were studied. Methods for service discovery will be described that take into account both local and remote services. These methods will then be evaluated in a SIP telephony infrastructure to decide where a call should be delivered. The location of a person is done by using the implemented service discovery. / Med en ökad användning av elektroniska enheter blir behovet av trådlösa tjänster, speciellt context-medvetna tjänster i så kallade Personal Area Network (PAN), ett område med betydlig potential. Service Discovery är en grundläggande funktion. Även om flera service discovery protocols har implementerats finns det behov av ett specifikt protokoll för PAN-miljöer då egenskaperna hos ett PAN skiljer sig från andra nätverksmiljöer. Således studerades de specifika krav för service discovery från ett PAN perspektiv. Metoder för service discovery kommer att ta med i beräkningen båda lokala och avlägna tjänster. Dessa metoder utvärderas i en SIP telephony infrastructure för att avgöra var en påringning ska levereras. Lokalisering av en användare sker genom det implementerade service discovery-protokollet.
6

Amélioration des adresses CGA et du protocole SEND pour un meilleur support de la mobilité et de nouveaux services de sécurité / Improving CGA addresses and the SEND protocol for a better mobility support and new security services

Cheneau, Tony 07 January 2011 (has links)
A l'origine conçus pour protéger le protocole de Découverte de Voisins (Neighbor Discovery Protocol, NDP) en IPv6, les adresses générées de manière cryptographique (Cryptographically Generated Addresses, CGA) et le protocole SEND (Secure Neighbor Discovery) doivent maintenant s'adapter au contexte de mobilité et à ses nouvelles fonctionnalités. Cette mobilité revêt de nombreuses formes : mobilité du noeud (Mobile IPv6, MIPv6), mobilité des routeurs (Network Mobility, NEMO) ou encore mobilité gérée par le réseau (Proxy Mobile IPv6). De nombreux changements doivent être opérés dans le protocole SEND : les opérations cryptographiques doivent être allégées pour les terminaux à faible capacité de calcul, les incompatibilités entre le partage d'adresse dans les protocoles de mobilité et le mécanisme de protection d'adresses de SEND doivent être corrigés, etc. Dans une première partie de cette thèse, nous présentons le protocole de Découverte de Voisins, les adresses CGA et le protocole de sécurité SEND. Nous étudions leurs limitations et, afin d'améliorer les performances, nous proposons l'utilisation de la cryptographie basée sur les courbes elliptiques (ECC). À travers une série de tests, nous mesurons l'impact de notre proposition. Par la suite, nous modifions les spécifications du protocole SEND afin de supporter de nouveaux algorithmes crytpographiques. Dans une deuxième partie, nous résolvons les incompatibilités entre le protocole SEND et les protocoles de mobilité (par ex. MIPv6) et entre le protocole SEND et les adresses anycast. Dans une dernière partie, nous présentons plusieurs contributions basées sur une utilisation dérivée des adresses CGA et du protocole SEND. / Originally designed to protect the Neighbor Discovery Protocol (NDP) (part of the IPv6 protocol suite), the Cryptographically Generated Addresses (CGA) and the Secure Neighbor Discovery (SEND) now need to be adapted to the context of Mobility and extended to new functionalities. The term "Mobility" encompasses many aspects, among them : node mobility (Mobile IPv6, MIPv6), router mobility (Network Mobility, NEMO) and network-based mobility management (Proxy Mobile IPv6, PMIPv6). Numerous changes need to be operated on the SEND protocol in order to comply with the Mobility : the cryptographic operations need to be adapted to operate on low power mobile nodes, the incompatibilities between the address sharing model of the mobile protocol and the address protections offered by SEND need to be fixed, etc. Firstly, we present the Neighbor Discovery protocol, the CGA addresses and the SEND protocol. We study their limitations, and, in order to improve their performances, we propose to replace the signature algorithm used in SEND (RSA) by the elliptic curves cryptography (ECC). We then evaluate the performances of our proposal. Subsequently, we modify the SEND protocol to include a signature algorithm selection mechanism. Secondly, we solve incompatilities between the SEND protocol and the mobility protocols (e.g. MIPv6) and between the SEND protocol and the anycast addresses. Finally, we present our contributions containing a derivate use of the CGA addresses and the SEND protocol.
7

Multicasting in Intra and Inter Domain Networks

Khan, Shahzad Hayat, Badshah, Jehan January 2011 (has links)
Multicasting in a network improves the efficiency to deliver an IP packet to multiple clients at the same time. Small to medium sized organizations implement this technology to enhance their network capability, which is otherwise not possible just with normal routing. However, to use this technology, it requires proper network design with tidy resource implementation.Network administrators prefer automatic deployment of multicast technology because it reduces the potential risk of prolonged down time during network troubleshooting. On the other hand, choosing an auto deployment technology could cause malfunctioning in the network. To avoid such malfunctioning, we used two technologies: Auto-RP (Auto- Rendezvous Point) [1] and Bootstrap [2] in our network. A problem that occurs here is that if different domains with similar or different technologies want to share their resources with each other, then regular multicasting cannot connect them for successful communication. Also, if an administrator wishes to provide short and redundant paths within a domain, then these two technologies do not possess the ability to do so.The thesis presents issues in intra-domain and inter-domain multicast networks; it also focuses on Auto-RP (Auto Rendezvous Point) and BSR (Bootstrap Router) which are technologies related to multicasting. This project highlights the importance of multicasting security and will brief the problems associated with these two technologies. It will offer a better solution with a properly implemented design guide. The study uses MSDP (Multicast Source Discovery Protocol) [3] which connects two domains with multicasting capabilities for exchanging the source and providing redundancy in intra- domain. The work implements MBGP (Multicast Border Gateway Protocol) [4] to avoid a situation in which there is no multicast support on one of the service provider(s) end. Keywords:Auto-RP (Auto-Rendezvous Point), BSR (Bootstrap Router), MSDP (Multicast Source Discovery Protocol), MBGP (Multicast Border Gateway Protocol)
8

Analýza a demonstrace vybraných IPv6 útoků / An Analysis of Selected IPv6 Network Attacks

Pivarník, Jozef January 2013 (has links)
This master's thesis analyses and demonstrates selected IPv6 attacks including two Man-in-the-Middle attacks and one Denial of Service attack - Rogue Router Advertisement, Neighbor Cache Poisoning and Duplicate Address Detection DoS, respectively. In the first part the author presents necessary information related to the issue and provides detailed information on how to realize these attacks in practice using publicly available tools. The second part of the thesis presents various ways of mitigating presented attacks, analyses implementations of some of those countermeasures on Cisco and H3C devices and discussess their applicability.
9

QoS routing for mobile ad hoc networks using genetic algorithm

Abdullah, Jiwa January 2007 (has links)
Mobile Ad Hoc Networks (MANETs) are a class of infrastructure less network architecture which are formed by a collection of mobile nodes that communicate with each other using multi-hop wireless links. They eliminate the need for central management, hence each node must operate cooperatively to successfully maintain the network. Each node performs as a source, a sink and a router. Future applications of MANETs are expected to be based on all-IP architecture, carrying a multitude of real-time multimedia applications such as voice, video and data. It would be necessary for MANETs to have an efficient routing and quality of service (QoS) mechanism to support diverse applications. This thesis proposes a set of cooperative protocols that provide support for QoS routing. The first is the on-demand, Non-Disjoint Multiple Routes Discovery protocol (NDMRD). NDMRD allows the establishment of multiple paths with node non-disjoint between source and destination node. It returns to the source a collection of routes with the QoS parameters. The second part of the protocol is the Node State Monitoring protocol for the purpose of monitoring, acquisition, dissemination and accumulation of QoS route information. The third part of the protocol implements the QoS route selection based on a Genetic Algorithm. The GA is implemented online with predetermined initial population and weighted-sum fitness function which operates simultaneously on the node bandwidth, media access delay, end to end delay and the node connectivity index (NCI). The term node connectivity index is a numerical value designed to predict comparatively the longest time a node-pair might be connected wirelessly.

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