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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.

Efficient Information Dissemination in Vehicular Networks with Privacy Protection

Cheng, Xiaolu 01 January 2018 (has links)
Vehicular ad hoc network (VANET) is a key component of intelligent transportation System (ITS). In VANETs, vehicles and roadside units exchange information for the purpose of navigation, safe driving, entertainment and so on. The high mobility of vehicles makes efficient and private communications in VANETs a big challenge. Improving the performance of information dissemination while protecting data privacy is studied in this research. Meet-Table based information dissemination method is first proposed, so as to improve the information dissemination, and to efficiently distribute information via utilizing roadside units, Cloud Computing, and Fog Computing. A clustering algorithm is proposed as well, to improve the stability for self-organized cluster-based dissemination in VANETs on highways. Then, fuzzy neural networks are used to improve the stability and security of routing protocols, AODV, and design a novel protocol, GSS-AODV. To further protect data privacy, a multi-antenna based information protection approach for vehicle-to-vehicle(V2V) communications is also proposed.

Energy-aware Ad Hoc on-demand distance vector routing protocol and optimizing the blocking problem induced in wireless Ad Hoc networks

El Moutia, Abdallah 31 March 2004 (has links)
The purpose of this thesis was to investigate some of the issues related to routing and medium access control protocol in ad hoc networks. In routing protocol, the goal is to tackle the power consumption problem and to present a case for using new cost energy-aware metric for Ad Hoc On-Demand Distance Vector (AODV). The idea of the new cost metric is to be able to avoid routes with a low energy capacity. By using this approach, high efficiency in energy consumption can be achieved in Ad-Hoc networks. The second goal of this thesis was to investigate the blocking problem induced by Request-to-Send/Clear-to-Send (RTS/CTS) mechanism in detail and provide a solution to overcome that problem. To do so, a new parameter is proposed by which the Medium Access control (MAC) protocol will decide when to switch between RTS/CTS mechanism (the 4-way-handshaking) and the Basic Access method (the 2-way-handshaking) in order to reduce the effect of the blocking problem in Ad Hoc networks.

Design and Implementation of User Level Socket Application Programming Interface with Socket Splitting and Mediation

Holzer, Scott Walter 01 November 2010 (has links) (PDF)
Over the past few decades, the size and scope of the Internet has grown exponentially. In order to maintain support for legacy clients, new applications and services have been limited by dependence on traditional sockets and TCP, which provide no support for modifying endpoints after connection setup. This forces applications to implement their own logic to reroute communications to take advantage of composable services or handle failover. Some solutions have added socket operations that allow for endpoints to be redirected on the fly, but these have been limited in scope to handling failover and load balancing. We present two new sets of socket operations. The first set allows servers to dynamically insert and remove intermediaries into communication streams. This allows applications to decide in real time whether to use services provided by 3rd parties such as encryption, filtering, and compression. In this way, applications can employ dynamic service composition to customize communication between clients and servers. The second set of operations allows sockets to be split such that all frames written to the socket are sent to multiple recipients. This is useful for implementing fast failover and passive communication monitoring. All of these operations are implemented in user space and gracefully handle legacy TCP clients, making quick deployment of distributed Internet applications a real possibility. Performance tests of the new operations on remote hosts show that the overhead introduced is not prohibitive.

Fault/configuration management for wireless ad-hoc network

Doshi, Abhay 08 August 2002 (has links)
An ad hoc network is maintained by the combined efforts of all the mobile nodes themselves, who often operate under severe constraints, such as limited battery power, variable link quality, and limited storage capacity. As a result, there is a growing need for enhanced fault and configuration management solutions to help in tracking problems as well as solving them. Viable network architecture for a wireless ad-hoc environment, which takes advantages of both hierarchical and distributed architectures, has been investigated. A complete design solution is proposed which makes ad-hoc environments less susceptible to faults. Results shows that by applying the proposed power saving technique, network load due to control traffic may be significantly reduced. Based on other gathered statistics, we can set the optimal value of maximum number of nodes allowed in a cluster for efficient performance to be 35 for a specific scenario.

Simulation and analysis of network traffic for efficient and reliable information transfer

Boppana, Neelima 21 November 2002 (has links)
With the growing commercial importance of the Internet and the development of new real-time, connection-oriented services like IP-telephony and electronic commerce resilience is becoming a key issue in the design of TP-based networks. Two emerging technologies, which can accomplish the task of efficient information transfer, are Multiprotocol Label Switching (MPLS) and Differentiated Services. A main benefit of MPLS is the ability to introduce traffic-engineering concepts due to its connection-oriented characteristic. With MPLS it is possible to assign different paths for packets through the network. Differentiated services divides traffic into different classes and treat them differently, especially when there is a shortage of network resources. In this thesis, a framework was proposed to integrate the above two technologies and its performance in providing load balancing and improving QoS was evaluated. Simulation and analysis of this framework demonstrated that the combination of MPLS and Differentiated services is a powerful tool for QoS provisioning in IP networks.

A grid computing network platform for enhanced data management and visualization

Delgado, Javier 28 March 2007 (has links)
This thesis presents a novel approach towards providing a collaboration environment by using Grid Computing. The implementation includes the deployment of a cluster attached to a mural display for high performance computing and visualization and a Grid-infrastructure for sharing storage space across a wide area network and easing the remote use of the computing resources. A medical data processing application is implemented on the platform. The outcome is enhanced use of remote storage facilities and quick return time for computationally-intensive problems. The central issue of this thesis work is thus one that focuses on the development of a secure distributed system for data management and visualization to respond to the need for more efficient interaction and collaboration between technical researchers and medical professionals. The proposed networked solution is envisioned such as to provide synergy for more collaboration on theoretical and experimental issues involving analysis, visualization, and data sharing across sites.

Pervasive Spectrum Sharing for Improved Wireless Experience

Rahman, Mostafizur 01 January 2020 (has links) (PDF)
Spectrum sharing among cellular users has been a promising approach to attain better efficiency in the use of the limited spectral bands. The existing dynamic spectrum access techniques include sharing of the licensed spectrum bands by allowing other 'secondary' users to use the bands if the licensee 'primary' user is idle. This primary-secondary spectrum sharing is limited in terms of design space, and may not be sufficient to meet the ever-increasing demand of connectivity and high signal quality to improve the end-users' wireless experience. The next step to increase spectrum efficiency is to design markets where sharing takes place pervasively among primary providers rather than leaving it to the limited case of when the primary licensee is idle. Attaining contractual pervasive spectrum sharing among primary providers, a.k.a. co-primary spectrum sharing (Co-PSS), involves additional costs for the users, e.g., roaming fee. Co-PSS without additional charge to the users poses two major challenges: 1) regulatory approaches must be introduced to incentivize and encourage providers for sharing spectrum resources, and 2) small providers in Co-PSS markets may freeride on large providers' networks as the customers of the small providers may be using the spectrum and infrastructure resources of large providers. Such freeriding opportunities in Co-PSS markets must be minimized to realize the benefits of primary-level sharing. This dissertation considers a subsidy-based spectrum sharing (SBSS) market to facilitate Co-PSS where providers are explicitly incentivized to share spectrum resources. It focuses on minimizing freeriding in SBSS markets by introducing a novel game-theoretic and heuristic algorithm. It proposes ''Proof of Sharing (PoS)'', an architecture to account spectrum sharing. It also demonstrates how to utilize PoS-like crowdsourced data to predict cellular tower locations which help to generate a truthful coverage map. Finally, this dissertation extends Co-PSS to two new models with government infrastructure and spectrum as rewards.

HIDRA: Hierarchical Inter-domain Routing Architecture

Clevenger, Bryan 01 May 2010 (has links) (PDF)
As the Internet continues to expand, the global default-free zone (DFZ) forwarding table has begun to grow faster than hardware can economically keep pace with. Various policies are in place to mitigate this growth rate, but current projections indicate policy alone is inadequate. As such, a number of technical solutions have been proposed. This work builds on many of these proposed solutions, and furthers the debate surrounding the resolution to this problem. It discusses several design decisions necessary to any proposed solution, and based on these tradeoffs it proposes a Hierarchical Inter-Domain Routing Architecture - HIDRA, a comprehensive architecture with a plausible deployment scenario. The architecture uses a locator/identifier split encapsulation scheme to attenuate both the immediate size of the DFZ forwarding table, and the projected growth rate. This solution is based off the usage of an already existing number allocation policy - Autonomous System Numbers (ASNs). HIDRA has been deployed to a sandbox network in a proof-of-concept test, yielding promising results.

Optimizing Peer Selection among Internet Service Providers (ISPs)

Mustafa, Shahzeb 01 January 2021 (has links)
Connections among Internet Service Providers (ISPs) form the backbone of the Internet. This enables communications across the globe. ISPs are represented as Autonomous Systems (ASes) in the global Internet and inter-ISP traffic exchange takes place via inter-AS links, which are formed based on inter-ISP connections and agreements. In addition to customer-provider agreements, a crucial type of inter-ISP agreement is peering. ISP administrators use various platforms like AP-NIC and NANOG networking events for establishing new peering connections in accordance with their business and technical needs. Such methods are often inefficient and slow, potentially resulting in missed opportunities or sub-optimal routes. The process can take several months with excessive amounts of paperwork. We investigate developing tools and algorithms that can help make the inter-AS connection formation more dynamic and reliable by helping ISPs make informed decisions, in line with their needs. We analyze the largest public datasets from CAIDA and PeeringDB to identify common trends and requirements that ISPs have in the context of peering. Using this analysis, we develop a simple yet effective peering predictor model, that identifies ISP pairs that show promising signs of forming a good peering relation. For motivating research and development in this area, we develop an Internet eXchange Point (IXP) emulator that ISP admins can use as a testbed for analyzing different peering policies within an IXP. We further extend our ideas about peering to wireless cellular network and design a working wireless peering model, and present how optimal agreements can be reached and best wireless peering partners and areas can be chosen. With the exponential increase in traffic volume and dependency on the Internet, it is crucial that the underlying network is dynamic and robust. To this end, we address issues with peering from multiple angles and develop novel models for automation and optimization.

Exploring Radio Frequency Positioning Methods and Their Use in Determining User Context in Public Spaces

Guercio, Remy 01 January 2016 (has links)
RF positioning methods have various tradeoffs that make them suitable for differing applications. This thesis identifies the most prominent positioning methods and deter-mines their suitability for context aware applications in pub-lic spaces using a number of different factors. This thesis first explores the physical characteristics of GPS, GSM, 802.11 and Bluetooth focusing on coverage and accuracy in both a historical and forward looking context. Next, it explores what it means for an application to be context aware and how that translates into building applications that are used in the context of public places. This thesis then reflects on the intersection of the two and explores some challenges related to practical implementations. In order to further explore these challenges, it assesses a high accuracy use case of merging Bluetooth positioning with augmented reality and virtual reality applications. We find that in the last decade Bluetooth has made rapid advancements in relation to competing technologies, but it is still far from ideal in all situations, especially when the situation requires extremely high accuracy.

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