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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

Service-Oriented Information-Centric Vehicular Ad-hoc Networks

Modesto, Felipe 29 May 2019 (has links)
With Vehicular mobile communication becoming a daily requirement and an ever increasing number of services being available to passengers, it is clear that vehicular networks efficient communication systems. VANETs, one of the most significant trends in ad-hoc networking, has much to gain from improved content delivery and one of the leading contenders for mobile networks is the Information-Centric networking approach. Its peculiarities define the Vehicular Environment requires specialized solutions, tailored for highly mobile environments. The main contribution of this thesis is the introduction of a novel architecture and components. We perform extensively discuss Information-Centric Vehicular Ad-hoc Networks. Additionally, we perform an in-depth analysis of bus-based transit systems into VANETs not only as participating members but as service providers and official agents including roles and potential challenges. We perform statistical analysis and analyze world data to denote the intrinsic potential of public transit systems. From the discussions presented, we introduce a novel service-based system architecture for Information-Centric Networking named SEVeN. The proposed model is designed to enable service exchange and service management in highly competitive vehicular ad-hoc networks. The proposed SEVeN architecture includes the introduction of a novel purpose-defined naming policy and service sub-layer as well as a service prioritization policy named LBD. We also discuss the current state of ICN caching in VANET, existing issues faced by vehicular networks and potential approaches based on intermediate cache coordination that can be taken to mitigate existing shortcommings. We perform a series of simulations and analyze the efficiency of popular caching in various network configurations to denote current shortcomings. From this discussion, we propose a cache content insertion policies, UG-Cache and MG-Cache, for ICN-VANETs. In these cache policies, cache insertion decisions are made based on recommendations from content sender dependent on request frequency and cache distance. We also introduce a caching policy based on collaborative observation of locality in request frequency, designed to allow vehicles to preemptively distribute and store in a reserved portion of the cache based on the cooperative observation of requests with provider-based location correlation. All novel elements proposed by this thesis are discussed, described, evaluated within the chapters of this thesis.
2

Protocol and System Design for a Service-centric Network Architecture

Huang, Xin 01 February 2010 (has links)
Next-generation Internet will be governed by the need for flexibility. Heterogeneous end-systems, novel applications, and security and manageability challenges require networks to provide a broad range of services that go beyond store-and-forward. Following this trend, a service-centric network architecture is proposed for the next-generation Internet. It utilizes router-based programmability to provide packet processing services inside the network and decompose communications into these service blocks. By providing different compositions of services along the data path, such network can customize its connections to satisfy various communication requirements. This design extends the flexibility of the Internet to meet its next-generation challenges. This work addresses three major challenges in implementing such service-centric networks. Finding the optimal path for a given composition of services is the first challenge. This is called "service routing" since both service availability and routing cost need to be considered. Novel algorithms and a matching protocol are designed to solve the service routing problem in large scale networks. A prototype based on Emulab is implemented to demonstrate and evaluate our design. Finding the optimal composition of services to satisfy the communication requirements of a given connection is the second challenge. This is called "service composition." A novel decision making framework is proposed, which allows the deduction of the service composition problem into a planning problem and automates the composition of service according to specified communication requirements. A further investigation shows that extending this decision making framework to combine the service routing and service composition problems yields a better solution than solving them separately. Run-time resource management on the data plane is the third challenge. Several run-time task mapping approaches have been proposed for Network Processor systems. An evaluation methodology based on queuing network is designed to systematically evaluate and compare these solutions under various network traffic scenarios. The results of this work give qualitative and quantitative insights into next-generation Internet design that combines issues from computer networking, architecture, and system design.
3

Context Sensitive Interaction Interoperability for Distributed Virtual Environments

Ahmed, Hussein Mohammed 23 June 2010 (has links)
The number and types of input devices and related interaction technique types are growing rapidly. Innovative input devices such as game controllers are no longer used just for games, propriety consoles and specific applications, they are also used in many distributed virtual environments, especially the so-called serious virtual environments. In this dissertation a distributed, service based framework is presented to offer context-sensitive interaction interoperability that can support mapping between input devices and suitable application tasks given the attributes (device, applications, users, and interaction techniques) and the current user context without negatively impacting performances of large scale distributed environments. The mapping is dynamic and context sensitive taking into account the context dimensions of both the virtual and real planes. What device or device component to use, how and when to use them depend on the application, task performed, the user and the overall context, including location and presence of other users. Another use of interaction interoperability is as a testbed for input devices, and interaction techniques making it possible to test reality based interfaces and interaction techniques with legacy applications. The dissertation provides a description how the framework provides these affordances and a discussion of motivations, goals and the addressed challenges. Several proof of the concept implementations were developed and an evaluation of the framework performance (in terms of system characteristics) demonstrates viability, scalability and negligible delays. / Ph. D.

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