1501 |
Technoeconomic aspects of next-generation telecommunications including the Internet serviceUnknown Date (has links)
This research is concerned with the technoeconomic aspects of modern and next-generation telecommunications including the Internet service. The goal of this study thereof is tailored to address the following: (i) Reviewing the technoeconomic considerations prevailing in telecommunication (telco) systems and their implicating futures; (ii) studying relevant considerations by depicting the modern/next-generation telecommunications as a digital ecosystem viewed in terms of underlying complex system evolution (akin to biological systems); (iii) pursuant to the digital ecosystem concept, co-evolution modeling of competitive business structures in the technoeconomics of telco services using dichotomous (flip-flop) states as seen in prey-predator evolution; (iv) specific to Internet pricing economics, deducing the profile of consumer surplus versus pricing model under DiffServ QoS architecture pertinent to dynamic- , smart- and static-markets; (v) developing and exemplifying decision-making pursuits in telco business under non-competitive and competitive markets (via gametheoretic approach); (vi) and modeling forecasting issues in telco services addressed in terms of a simplified ARIMA-based time-series approach, (which includes seasonal and non-seasonal data plus goodness-fit estimations in time- and frequency-domains). Commensurate with the topics indicated above, necessary analytical derivations/models are proposed and computational exercises are performed (with MatLabTM R2006b and other software as needed). Extensive data gathered from open literature are used thereof and, ad hoc model verifications are performed. Lastly, results are discussed, inferences are made and open-questions for further research are identified. / by Renata Cristina Tourinho Sardenberg. / Thesis (Ph.D.)--Florida Atlantic University, 2010. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2010. Mode of access: World Wide Web.
|
1502 |
Network Fault Tolerance SystemSullivan, John F 01 May 2000 (has links)
The world of computers experienced an explosive period of growth toward the end of the 20th century with the widespread availability of the Internet and the development of the World Wide Web. As people began using computer networks for everything from research and communication to banking and commerce, network failures became a greater concern because of the potential to interrupt critical applications. Fault tolerance systems were developed to detect and correct network failures within minutes and eventually within seconds of the failure, but time-critical applications such as military communications, video conferencing, and Web-based sales require better response time than any previous systems could provide. The goal of this thesis was the development and implementation of a Network Fault Tolerance (NFT) system that can detect and recover from failures of network interface cards, network cables, switches, and routers in much less than one second from the time of failure. The problem was divided into two parts: fault tolerance within a single local area network (LAN), and fault tolerance across many local area networks. The first part involves the network interface cards, network cables, and switches within a LAN, which the second part involves the routers that connect LANs into larger internetworks. Both parts of the NFT solution were implemented on Windows NT 4.0 PC's connected by a switched Fast Ethernet network. The NFT system was found to correct system failures within 300 milliseconds of the failure.
|
1503 |
Real time communications over on-board mobile networksMalik, Muhammad Ali, Computer Science & Engineering, Faculty of Engineering, UNSW January 2007 (has links)
The Internet Engineering Task Force (IETF) has recently released routing standards that allow deployment of TCP/IP local area networks (LANs) onboard a moving vehicle and yet maintain permanent connectivity of the onboard LAN to the Internet via a vehicular mobile router. This recent development opens up new opportunities for providing efficient mobile computing for users on the move, especially for commuters traveling on public transports. Supporting real-time communications, e.g. IP Telephony, on-line video on demand, etc., over such onboard mobile networks is the main motivation of this thesis. Due to the volatility of the wireless bandwidth available to connect the moving LAN to the Internet at different locations of the trip, supporting on-line services that require bandwidth guarantees becomes a challenging task. The main problem investigated is how to provide bandwidth guarantee efficiently, effectively, and in a scalable manner in the context of moving onboard networks. To achieve the goal, a systematic approach is taken that involves (i) designing a signalling protocol that allows transparent bandwidth reservation for the aggregate demand of all onboard users in the vehicle, and (ii) proposing effective aggregation and bandwidth reservation policies that aim to maximize the chances of successful reservation and minimize the bandwidth and processing overhead in critical network elements. Mathematical models are derived to evaluate the performance of proposed solutions. These models are validated using discrete event simulation. One important conclusion reached is that onboard mobile communication provides significant aggregation and centralized management opportunities that must be exploited to provide a scalable solution to the bandwidth guarantee problem in mobile communications. The techniques proposed and analyzed in this thesis to exploit such aggregation opportunities constitute the original contribution to knowledge.
|
1504 |
QoS enabled IP based wireless networking : design, modelling and performance analysisGyasi-Agyei, Amoakoh January 2003 (has links)
Quality of service differentiation has never achieved much attention and relevance until the advent of the convergence of mobile wireless network and the fixed Internet, that is, Internet Protocol ( IP ) based mobile wireless networks, or wireless Internet. These networks are poised to support multimedia applications ' traffic with diverse QoS sensitivities. To date, most traffic transferred over the Internet still undergo best - effort forwarding, which does not guarantee whether or not traffic sent by a source gets to the intended destination, let alone loss and timing bounds. The major contribution of this thesis is three - fold. First, the thesis proposes a QoS - enabled wireless Internet access architecture, which leverages the micromobility in wireless standards to reduce mobile IP weaknesses, such as long handoff delay, to achieve effective interworking between mobile wireless networks and the global, fixed Internet. Although the idea here is applicable to any wireless standard, the design examples in this thesis are based on the IEEE 802.11b wireless local area network ( WLAN ) standard. Second, it proposes a framework for a class of wireless channel state dependent packet scheduling schemes, which consider the QoS requirements of the applications ' traffic ; the wireless channel state ( reflected in instantaneous data rate or noise level ) ; and optimises the usage of the expensive wireless resource. The operation of the QoS - enabled, channel state - dependent packet scheduler is analysed using optimisation theory, eigenanalysis and stochastic modelling. Third, the thesis analyses the effects of wireless channel properties on differentiated QoS ( DQoS ) schemes, using two - dimensional, channel - state - dependent queuing theory, matrix analytic methods to stochastic modelling and eigenanalysis. The ana - lytical model of DQoS schemes, especially models accounting for user scenarios such as speed of motion and wireless channel properties, such as fading, spatio - temporarily varying quality and low rate, is not properly covered in the open literature, and hence was a motivation for this part of the thesis. The wireless channel is discretized into discrete - time Markovian states based on the received signal - to - noise plus interference ratio ( SNIR ), which also reflects on the instantaneous link quality. The link quality, in turn, influences the QoS experienced by the transported applications sitting on top of the ISO / OSI protocol hierarchy. The parameters of the Markovian states are evaluated using realistic physical channel noise models and transceiver characteristics, such as modem. [ Different modems ( modulator / demodulator ) yields different transceiver properties such as sensitivity. The analysis in the thesis adopts QPSKand BPSK modulation. ] Source traffic models are used in the analysis. Lastly, the thesis provides an extensive introduction to, and provides a detailed background material for the new area of mobile wireless Internet systems, upon which considerable future research can be based. / Thesis (Ph.D.)--School of Electrical and Electronic Engineering, 2003.
|
1505 |
On reliable and scalable management of wireless sensor networksBapat, Sandip Shriram, January 2006 (has links)
Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 164-170).
|
1506 |
Reliable and secure data transport in large scale wireless networks of embedded devicesNaik, Vinayak Shashikant, January 2006 (has links)
Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 105-111).
|
1507 |
Unified distribution of pseudonyms in hybrid ephemeral vehicular networksBenin, Joseph Thomas 08 November 2012 (has links)
This research devises a unified method for the distribution of pseudonyms in hybrid ephemeral vehicular networks (VNs), which are often referred to as vehicular ad hoc networks (VANETs), for the purposes of refill, intra-regional, and inter-regional movement. This work addresses a significant impediment to the use of pseudonyms, which has been almost universally accepted (and is on the verge of being standardized by the Institute for Electrical and Electronic Engineers (IEEE) and the Society for Automotive Engineers (SAE) as the best means to balance attribution and privacy to maximize the value of infrastructure deployment and citizen acceptability (i.e. use). The results include a pseudonym distribution protocol that maximizes ease of use while not compromising the security or privacy pseudonyms afford. These results contribute to the solution, in a scalable, adaptive, and bandwidth efficient manner, one of the remaining impediments to the adoption of VANETs. The new method shows improved performance compared to a baseline pseudonym distribution method that does not take these factors into consideration.
|
1508 |
Routing and Network Design in Delay Tolerant NetworksZhao, Wenrui 11 October 2006 (has links)
Delay tolerant networks (DTNs) are a class of emerging networks that exhibit significantly different characteristics from today's Internet, such as intermittent connectivity, large delay, and high loss rates. DTNs have important applications in disaster relief, military, rural Internet access, environmental sensing and surveillance, interplanetary communication, underwater sensing, and vehicular communication. While not the common case for networking, DTNs represent some of the most critical cases, where the ability to communicate can make a huge difference for human lives.
Supporting effective communication in DTNs, however, is challenging. First, with intermittent connectivity, DTNs are often extremely limited in capacity. Second, given resource limitations and uncertainty in DTNs, it is critical to deliver data efficiently and robustly. The situation is especially acute for multicast which sends data to multiple destinations.
This thesis seeks to address these two issues. To enhance network capacity in DTNs, we propose a message ferrying scheme that exploits the use of special mobile nodes (called message ferries) and controlled device mobility to deliver data. Message ferries are utilized to transport data via mobility between sources and destinations. We develop a foundation for the control of the mobility of message ferries, and nodes if possible, to cooperatively deliver data under a variety of conditions. We also study another approach which deploys new nodes called throwboxes to enhance capacity. Throwboxes are small and inexpensive wireless devices. By relaying data between mobile nodes, throwboxes are able to create data transfer opportunities that otherwise would not exist. We systematically investigate the issues of deployment and routing, and develop algorithms for various deployment and routing approaches. Based on extensive evaluation, we obtain several findings to guide the design and operation of throwbox-augmented DTNs.
To address the issue of efficient and robust data delivery, we focus on DTN multicasting. Given the unique characteristics of DTNs, traditional solutions such as IP multicast can not be simply ported to DTNs. We identify the limitations of IP multicast semantics in DTNs and define new semantic models for DTN multicast. Based on these semantic models, we develop and evaluate several multicast routing algorithms with different routing strategies.
|
1509 |
Making infrastructure visible: a case study of home networkingChetty, Marshini 24 June 2011 (has links)
In this dissertation, I examine how making infrastructure visible affects users' engagement with that infrastructure, through the case study of home networking. I present empirical evidence of the visibility issues that home networks present to users and how these results informed the design of a prototype called Kermit to visualize aspects of the home network. Through my implementation and evaluation of Kermit, I derive implications for making infrastructure visible in ways that enable end-users to manage and understand the systems they use everyday. I conclude with suggestions for future work for making home networks, and infrastructure more generally, more visible.
|
1510 |
Wide-area route control for online servicesValancius, Vytautas 04 May 2012 (has links)
Accelerated by on-demand computing, the number and diversity of the
Internet services is increasing. Such online services often have unique
requirements for the underlying wide-area network: For instance, online
gaming service might benefit from low delay and jitter paths to client,
while online data backup service might benefit from cheaper paths.
Unfortunately, today's Internet does not accommodate fine-grained,
service-specific wide-area route control. In this dissertation, I achieve
the following goals: 1) improve the access to the routes, 2) quantify
the benefits of fine-grained route control, and 3) evaluate the
efficiency of current payment schemes for the wide-area routes.
* Improving access to wide-area route control. Online services
face significant technological and procedural hurdles in
accessing the routes: Each service in need to control the Internet
routes, has to obtain own equipment, Internet numbered resources, and
establish contracts with upstream ISPs. In this dissertation, I propose
and describe implementation and deployment of a secure and scalable
system which provides on-demand access to the Internet routes. In
setting such as cloud data center, the system can support multiple
online services, providing each service with an illusion of direct
connectivity to the neighboring Internet networks, which, for all
practical purposes, allows services to participate fully in the
Internet routing.
* Quantifying the benefits of fine-grained route control. Even
if online services are presented with wide-area route choice, it is not
clear how much tangible benefit such choice provides. Most modern Online
Service Providers (OSP) rely primarily on the content routing to
improve network performance between the clients and the replicas. In
this dissertation, I quantify the potential benefit the OSPs can gain if
they perform a joint network and content routing. Among other findings,
I find that by performing joint content and network routing, OSPs can
achieve 22% larger latency reduction than can be obtained by content
routing alone.
* Modeling and evaluating the efficiency of the current payment
schemes for wide-area routes. Finally, increasing diversity and
sophistication of the online services participating in the Internet
routing poses a challenge to payment models used in today's
Internet. Service providers today charge business customers a blended
rate: a single, "average" price for unit of bandwidth, without regard
to cost or value of individual customer's flows. In my dissertation, I
set to understand how efficient this payment model is and if more
granular payment model, accounting for the cost and value of different
flows could increase the ISP profit and the consumer surplus. I develop
an econometric demand and cost model and map three real-world ISP data
sets to it. I find that ISPs can indeed improve the economic efficiency
with just a few pricing tiers.
|
Page generated in 0.0407 seconds