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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.
141

Traffic and performance evaluation for optical networks. An Investigation into Modelling and Characterisation of Traffic Flows and Performance Analysis and Engineering for Optical Network Architectures.

Mouchos, Charalampos January 2009 (has links)
The convergence of multiservice heterogeneous networks and ever increasing Internet applications, like peer to peer networking and the increased number of users and services, demand a more efficient bandwidth allocation in optical networks. In this context, new architectures and protocols are needed in conjuction with cost effective quantitative methodologies in order to provide an insight into the performance aspects of the next and future generation Internets. This thesis reports an investigation, based on efficient simulation methodologies, in order to assess existing high performance algorithms and to propose new ones. The analysis of the traffic characteristics of an OC-192 link (9953.28 Mbps) is initially conducted, a requirement due to the discovery of self-similar long-range dependent properties in network traffic, and the suitability of the GE distribution for modelling interarrival times of bursty traffic in short time scales is presented. Consequently, using a heuristic approach, the self-similar properties of the GE/G/¿ are being presented, providing a method to generate self-similar traffic that takes into consideration burstiness in small time scales. A description of the state of the art in optical networking providing a deeper insight into the current technologies, protocols and architectures in the field, which creates the motivation for more research into the promising switching technique of ¿Optical Burst Switching¿ (OBS). An investigation into the performance impact of various burst assembly strategies on an OBS edge node¿s mean buffer length is conducted. Realistic traffic characteristics are considered based on the analysis of the OC-192 backbone traffic traces. In addition the effect of burstiness in the small time scales on mean assembly time and burst size distribution is investigated. A new Dynamic OBS Offset Allocation Protocol is devised and favourable comparisons are carried out between the proposed OBS protocol and the Just Enough Time (JET) protocol, in terms of mean queue length, blocking and throughput. Finally the research focuses on simulation methodologies employed throughout the thesis using the Graphics Processing Unit (GPU) on a commercial NVidia GeForce 8800 GTX, which was initially designed for gaming computers. Parallel generators of Optical Bursts are implemented and simulated in ¿Compute Unified Device Architecture¿ (CUDA) and compared with simulations run on general-purpose CPU proving the GPU to be a cost-effective platform which can significantly speed-up calculations in order to make simulations of more complex and demanding networks easier to develop.
142

The Shape of Consent: A Commentary on Emergent Forms within Suburbia

Shaver, Andrew Charles 03 June 2024 (has links)
This thesis reveals relationships between the neoliberal subject and the suburban subject relative to the built environment. It argues that today's "architecture" is an integration of digital and analog worlds. The thesis articulates that American society's subjectivity is imposed by a consumer condition that is tied to the iconography of suburban landscape, such as the iconic house shape or a recognizable brand icon. The advent of the internet accelerated this condition by providing additional conduits of capital-based icons to emerge from and merge with the suburbs. The work focuses on creating parallels between the American suburban landscape, the suburban home, digital infrastructure, and the emerging structures which merge with the internet. The thesis asserts that the suburban project dominates the entirety of the landscape and is the governing force building an incipient landscape. The written part of the thesis discusses how our modern identity, influenced by both physical and digital worlds, has evolved from suburban roots, while the visual commentary uses architectural drawings to reveal four modalities which frame our environment and shape our lives and interactions. / Master of Science / This thesis looks at how architecture shapes our lives and frames our interactions with the world around us. It specifically focuses on how suburban landscapes influence our identity and behavior, emphasizing the typical suburban elements like single-family housing, commercial strip development, and global consumer goods that define this environment. The rise of the internet has intensified these suburban influences by connecting the suburban environment more deeply with the flow of money and data. The research interrogates and uses images and symbols from the suburban landscape to comment on their latent impact on our surroundings and how they now blend with digital technology. The thesis develops the connections between the physical suburban environment and developing digital infrastructures to articulate emergent structures in their combination. The written part of the thesis discusses how our modern identity, influenced by both physical and digital worlds, has evolved from suburban roots. A visual commentary uses architectural drawings to reveal four modalities which frame our environment and shapes our lives and interactions.
143

Mobility and radio resource management in heterogeneous wireless networks

Liu, Xiaoshan, 劉曉杉 January 2006 (has links)
published_or_final_version / abstract / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy
144

A Study on Partially Homomorphic Encryption Schemes

Unknown Date (has links)
High processing time and implementation complexity of the fully homomorphic encryption schemes intrigued cryptographers to extend partially homomorphic encryption schemes to allow homomorphic computation for larger classes of polynomials. In this thesis, we study several public key and partially homomorphic schemes and discuss a recent technique for boosting linearly homomorphic encryption schemes. Further, we implement this boosting technique on CGS linearly homomorphic encryption scheme to allow one single multiplication as well as arbitrary number of additions on encrypted plaintexts. We provide MAGMA source codes for the implementation of the CGS scheme along with the boosted CGS scheme. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2017. / FAU Electronic Theses and Dissertations Collection
145

Unifying the conceptual levels of network security through the use of patterns

Unknown Date (has links)
Network architectures are described by the International Standard for Organization (ISO), which contains seven layers. The internet uses four of these layers, of which three are of interest to us. These layers are Internet Protocol (IP) or Network Layer, Transport Layer and Application Layer. We need to protect against attacks that may come through any of these layers. In the world of network security, systems are plagued by various attacks, internal and external, and could result in Denial of Service (DoS) and/or other damaging effects. Such attacks and loss of service can be devastating for the users of the system. The implementation of security devices such as Firewalls and Intrusion Detection Systems (IDS), the protection of network traffic with Virtual Private Networks (VPNs), and the use of secure protocols for the layers are important to enhance the security at each of these layers.We have done a survey of the existing network security patterns and we have written the missing patterns. We have developed security patterns for abstract IDS, Behavior–based IDS and Rule-based IDS and as well as for Internet Protocol Security (IPSec) and Transport Layer Security (TLS) protocols. We have also identified the need for a VPN pattern and have developed security patterns for abstract VPN, an IPSec VPN and a TLS VPN. We also evaluated these patterns with respect to some aspects to simplify their application by system designers. We have tried to unify the security of the network layers using security patterns by tying in security patterns for network transmission, network protocols and network boundary devices. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection
146

Progress towards push button verification for business process execution language artifacts

Unknown Date (has links)
Web Service Business Process Execution Language (BPEL) has become a standard language in the world of Service Oriented Architecture (SOA) for specifying interactions between internet services. This standard frees developers from low-level concerns involving platform, implementation, and versioning. These freedoms risk development of less robust artifacts that may even become part of a mission-critical system. Model checking a BPEL artifact for correctness with respect to temporal logic properties is computationally complex, since it requires enumerating all communication and synchronization amongst various services with itself. This entails modeling BPEL features such as concurrency, hierarchy, interleaving, and non-deterministic choice. The thesis will provide rules and procedures for translating these features to a veriable model written in Promela. We will use these rules to build a program which automates the translation process, bringing us one step closer to push button verification. Finally, two BPEL artifacts will be translated, manually edited, verified, and analyzed. / by Augusto Varas. / Thesis (M.S.C.S.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.
147

Web services cryptographic patterns

Unknown Date (has links)
Data security has been identified as one of the most important concerns where sensitive messages are exchanged over the network. In web service architecture, multiple distributed applications communicate with each other over the network by sending XML messages. How can we protect these sensitive messages? Some web services standards have emerged to tackle this problem. The XML Encryption standard defines the process of encrypting and decrypting all of an XML message, part of an XML message, or even an external resource. Like XML Encryption, the XML Signature standard specifies how to digitally sign an entire XML message, part of an XML message, or an external object. WS-Security defines how to embed security tokens, XML encryption, and XML signature into XML documents. It does not define new security mechanisms, but leverages existing security technologies such as encryption and digital signature. / by Keiko Hashizume. / Thesis (M.S.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.
148

A FRAMEWORK FOR ECONOMIC ANALYSIS OF NETWORK ARCHITECTURES

Murat Karakus (5931083) 17 January 2019 (has links)
<div>This thesis firstly surveys and summarizes the state-of-the-art studies from two research areas in Software Defined Networking (SDN) architecture: (i) control plane scalability and (ii) Quality of Service (QoS)-related problems. It also outlines the potential challenges and open problems that need to be addressed further for more scalable SDN control planes and better and complete QoS abilities in SDN networks. The thesis secondly presents a hierarchical SDN design along with an inter-AS QoS-guaranteed routing approach. This design addresses the scalability problems of control plane and privacy concerns of inter-AS QoS routing philosophies in SDN. After exploring the roots of control plane scalability problems in SDN, the thesis then proposes a metric to quantitatively evaluate the control plane scalability in SDN. Later, the thesis presents a general framework for economic analysis of network architectures and designs. To this end, the thesis defines and utilizes two metrics, Unit Service Cost Scalability and Cost-to-Service, to evaluate how SDN architecture performs compared to MPLS architecture in terms of unit cost for a service and cost of introducing a new service along with giving mathematical models to calculate Capital Expenditures (CAPEX) and Operational Expenditures (OPEX) of a network. Moreover, the thesis studies the problem of optimal final pricing for services by proposing an optimal pricing scheme for a service request with QoS in SDN environment while aiming to maximize benefits of both service providers and customers. Finally, the thesis investigates how programmable network architectures, i.e. SDN, affect the network economics compared to traditional network architectures, i.e. MPLS, in case of failures along with exploring the economic impact of failures in different SDN control plane models. </div>
149

Mobility and radio resource management in heterogeneous wireless networks

Liu, Xiaoshan, January 2006 (has links)
Thesis (Ph. D.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.
150

MSSPACC: Sistema d'execució paral·lela d'aplicacions amb especulació sobre entorns distribuïts

Puiggalí, Joan 07 November 2012 (has links)
The research we have conducted has been aimed at developing a new mechanism of extraction and use of parallelism at a high level, based on speculation techniques, in cluster environments. This allows our mechanism to be architecture independent and to be adapted to heterogeneous environments. As a drawback there are some limitations due to the fact of working at a high level, such as memory address access dependencies and those occurring in vector operations. The Master/Slave Speculative Parallelization Architecture for Computer Clusters (MSSPACC) is considered that works at the TLP taking advantage of the execution tools of the ILP level. It works at TLP level because the program is divided into threads which we call blocks. The blocks they are considered like single instructions and follow the same pattern of a superscalar processor ILP (input variables are considered like operands and the output like the result of the execution). / L’objectiu d’aquesta recerca és desenvolupar un nou mecanisme d'extracció i explotació del paral•lelisme basat en tècniques d'especulació a nivell d’aplicació sobre clústers. Així hem aconseguit que el sistema no tingui una dependència arquitectònica i poder adaptar-se a entorns heterogenis. Com a contrapartida ens hem trobat amb les limitacions degudes al fet de treballar a nivell d’aplicació, com són les dependències d’adreces d’accés a memòria i les provocades en operacions amb vectors. La proposta desenvolupada s’anomena Master/Slave Speculative Parallelization Architecture for Computer Clusters (MSSPACC) i es pot considerar que treballa a nivell TLP aprofitant les eines d’execució del nivell ILP. Divideix el programa en fils d’execució que anomenem blocs bàsics que s’executen seguint el mateix patró ILP d’un processador Superescalar, considerant que un bloc bàsic és equivalent a una instrucció, les variables d’entrada com a operants i les de sortida com al resultat de l’execució del bloc bàsic.

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