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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.
11

Technoeconomic aspects of next-generation telecommunications including the Internet service

Unknown 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.
12

A Simulation tool for CCS No. 7 network planning and evaluation.

January 1992 (has links)
by Lee Sui Yip. / Thesis (M.Sc.)--Chinese University of Hong Kong, 1992. / Includes bibliographical references. / Chapter Chapter1 --- Introduction / Chapter 1.1 --- Objectives of Common Channel Signalling --- p.1.1 / Chapter 1.1.1 --- Channel Associated Signalling --- p.1-1 / Chapter 1.1.2 --- Common Channel Signalling --- p.1.2 / Chapter 1.2 --- Functional Description --- p.1.3 / Chapter 1.3 --- Signalling Network Basics --- p.1.5 / Chapter 1.4 --- Network Topology --- p.1.9 / Chapter 1.5 --- Signalling Messages --- p.1.13 / Chapter Chapter2 --- Common Channel Signalling No. 7 Network of Hong Kong Telephone / Chapter 2.1 --- System Performance Criteria --- p.2.1 / Chapter 2.1.1 --- Post Dialing Delay --- p.2.2 / Chapter 2.1.2 --- Availability --- p.2.3 / Chapter 2.1.3 --- Survivabiliy --- p.2.3 / Chapter 2.2 --- Implementation Considerations --- p.2.4 / Chapter 2.2.1 --- System Constraints --- p.2.4 / Chapter 2.2.2 --- Number of Signal Transfer Points --- p.2.5 / Chapter 2.2.3 --- Signalling Modes and Assignments --- p.2.6 / Chapter 2.2.4 --- Signalling Link-sets and Diversity --- p.2.7 / Chapter 2.2.5 --- Post Dialing Delay --- p.2.7 / Chapter 2.3 --- The Common Channel Signalling Network of Hong Kong Telephone --- p.2.7 / Chapter Appendix : --- Queuing Delay Estimation --- p.2.9 / Chapter Chapter3 --- Message Routing Policy / Chapter 3.1 --- Originating Signalling Point --- p.3.2 / Chapter 3.2 --- Selection of Signalling Links --- p.3.3 / Chapter 3.3 --- Signal Transfer Points --- p.3.5 / Chapter 3.3.1 --- Same Cluster --- p.3.6 / Chapter 3.3.2 --- Adjacent Clusters --- p.3.6 / Chapter 3.3.3 --- Distant Clusters --- p.3.7 / Chapter 3.4 --- Destination Signalling Point --- p.3.8 / Chapter Appendix : --- STP Stages Estimation --- p.3.9 / Chapter Chapter4 --- Building the Simulation Model / Chapter 4.1 --- Modelling Objective --- p.4.1 / Chapter 4.2 --- The Cluster Level Model --- p.4.2 / Chapter 4.2.1 --- Message Generation --- p.4.2 / Chapter 4.2.2 --- Modelling Message Routing --- p.4.3 / Chapter 4.2.3 --- Modelling Failures --- p.4.5 / Chapter 4.2.4 --- The Simulation Procedures --- p.4.6 / Chapter 4.2.4.1 --- Processes --- p.4.6 / Chapter 4.2.4.2 --- Permanent Entities --- p.4.8 / Chapter 4.2.4.3 --- Initialization Routines --- p.4.9 / Chapter 4.3 --- The Signalling Point Level Model --- p.4.11 / Chapter 4.3.1 --- Message Generation and Routing --- p.4.13 / Chapter 4.3.2 --- Simulation Procedures --- p.4.13 / Chapter Chapter5 --- Network Planning and Evaluation with the Simulation Model / Chapter 5.1 --- Model Testing --- p.5.1 / Chapter 5.2 --- Comparison with Analytical Results --- p.5.2 / Chapter 5.3 --- Modelling with 1 STP Failure --- p.5.5 / Chapter 5.4 --- Simulation with Measured Data --- p.5.8 / Chapter 5.5 --- Network Performance Evaluation --- p.5.15 / Chapter 5.5.1 --- Normal Conditions --- p.5.15 / Chapter 5.5.2 --- STP Failures --- p.5.16 / Chapter 5.5.3 --- Signalling Link-set Failures --- p.5.17 / Chapter 5.6 --- Network Planning --- p.5.19 / Chapter 5.6.1 --- Re-allocation of Signalling Points --- p.5.21 / Chapter 5.6.2 --- Re-configuration of Signalling Network --- p.5.21 / Chapter 5.6.3 --- Associated Link Provision Policy --- p.5.22 / Chapter 5.6.4 --- New Message Routing Policy --- p.5.22 / Discussion and Conclusion / References
13

Development of a satellite network simulator tool and simulation of AX.25, FX.25 and a hybrid protocol for nano-satellite communications

Le Roux, Jan-Hielke 12 1900 (has links)
Thesis (MEng)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Nano-satellites are mostly used in lower earth orbit applications, where communication intervals are limited, often to a combined total of less than one hour per day. With these type of inherent limitations of lower earth orbits, there are also the physical size and equipment restriction of nano-satellites to consider, especially those of the CubeSat specification. It is of critical importance to use the limited time and communication resources as effectively as possible. The network protocol has a huge influence on reliability and throughput of a satellite network. An important requisite for designing, comparing and improving network protocols is a network protocol simulator, that is able to envisage the design results. Simulation can facilitate rapid development and unforeseen discoveries. Very little information is currently available regarding communication protocols used in nano-satellites. This thesis aims to explore and improve the current status of nano-satellite network simulation, as well as to demonstrate the development of an improved communication protocol strategy. It was found that there is a lack of proper simulation tools for satellite networks, which led to the development of SatSim. SatSim is a discrete event network simulation tool, developed in Python, which can be used to develop and analyse network protocols. SatSim was verified by comparing simulation results with other published results, which made use of different software tools and theoretical throughput calculations. AX.25 is one of the most commonly used network protocols in the nano-satellite industry. It was implemented in SatSim and verified with theoretical throughput calculations, as no other simulation data on AX.25 was available. AX.25 was used as a baseline protocol to improve upon. FX.25 was developed by the Stensat Group in an attempt to improve AX.25. FX.25 adds forward error correction to AX.25, by wrapping additional data around the AX.25 frames. This method maintains backward compatibility with AX.25. FX.25 was implemented in SatSim and the simulation results proved that FX.25 was a more reliable protocol than AX.25, as it can communicate at lower elevations and over noisier communication channels. However, the drawback of the additional forward error correction is the increased overhead, which reduces the overall payload data throughput. A modular AX/FX.25 protocol was then implemented in SatSim, to exploit the strengths of both protocols. This hybrid protocol yielded significant improvements to data throughput and can enable future software defined radio or hardware developments. / AFRIKAANSE OPSOMMING: Nano-satelliete word hoofsaaklik gebruik in lae-aard wentelbaan toepassings waar kommunikasietyd beperk is, soms tot minder as een uur per dag. Gepaardgaande met hierdie inherente beperking van lae-aard wentelbane, is daar ook die verminderde omvang en kapasiteit van nano-satelliete, veral ten opsigte van die CubeSat spesifikasie. Effektiewe aanwending van die beperkte tyd en kommunikasie-hulpbronne is dus noodsaaklik. Die keuse van netwerk protokol het ’n beduidende invloed op die betroubaarheid en data deurset van ’n satelliet netwerk. ’n Belangrike voorvereiste vir die ontwerp, vergelyking en verbetering van netwerk-protokolle, is ’n netwerk simulator. Beperkte inligting is tans beskikbaar oor kommunikasie protokolle in nano-satelliet toepassings. Hierdie tesis fokus op die verbetering van nano-satelliet netwerk-simulasie, asook die ontwikkelling van ’n verbeterde netwerk-protokol strategie vir nano-satelliet toepassings. Dit het na vore gekom dat daar ’n leemte is in die beskikbaarheid van simulasie sagteware wat gerig is op die ondersoek van satelliet netwerke. Hierdie waarneming het die ontwikkeling van SatSim genoop. SatSim is ’n diskrete-gebeurtenis netwerk-simulasie sagtewarepakket wat in die Python programmeertaal ontwikkel is om netwerk protokolle te ontwikkel en te analiseer. SatSim was geverifieer deur simulasies te vergelyk met die resultate van ander navorsingspublikasies, wat van verskillende sagtewarepakkette gebruik gemaak het, sowel as teoretiese deursetberekeninge. AX.25 is een van die netwerk protokolle wat mees algemeen in die nano-satelliet bedryf voorkom. AX.25 was geïmplementeer in SatSim en geverifieer met teoretiese deursetberekeninge. AX.25 was gebruik as ’n grondslag om op te verbeter. FX.25 was ontwikkel deur die Stensat Group in ’n poging om op AX.25 te verbeter. FX.25 voeg vorentoefoutkorreksie by tot AX.25, deur addisionele data tot die AX.25 netwerk pakkies te voeg. Hierdie benadering bewerkstellig agteruit-verenigbaarheid met AX.25. FX.25 was geïmplementeer in SatSim en simulasieresultate dui daarop dat FX.25 ’n meer betroubare protokol is as AX.25, omdat dit teen laer elevasiehoeke en oor swakker kommunikasiekanale kan kommunikeer. Die verbeterde betroubaarheid is ten koste van datadeurset, as gevolg van die toevoeging van die vorentoe-foutkorreksiedata. ’n Modulêre AX/FX.25 protokol was geïmplemeteer om te kapitaliseer op die sterk eienskappe van beide protokolle. Hierdie hibriede protokol het ’n beduidende verbetering gelewer ten opsigte van data deurset en kan toekomstige sagteware-gedefinieerde radio en hardewaretoepassings stimuleer.
14

An investigation into the control of audio streaming across networks having diverse quality of service mechanisms

Foulkes, Philip James January 2012 (has links)
The transmission of realtime audio data across digital networks is subject to strict quality of service requirements. These networks need to be able to guarantee network resources (e.g., bandwidth), ensure timely and deterministic data delivery, and provide time synchronisation mechanisms to ensure successful transmission of this data. Two open standards-based networking technologies, namely IEEE 1394 and the recently standardised Ethernet AVB, provide distinct methods for achieving these goals. Audio devices that are compatible with IEEE 1394 networks exist, and audio devices that are compatible with Ethernet AVB networks are starting to come onto the market. There is a need for mechanisms to provide compatibility between the audio devices that reside on these disparate networks such that existing IEEE 1394 audio devices are able to communicate with Ethernet AVB audio devices, and vice versa. The audio devices that reside on these networks may be remotely controlled by a diverse set of incompatible command and control protocols. It is desirable to have a common network-neutral method of control over the various parameters of the devices that reside on these networks. As part of this study, two Ethernet AVB systems were developed. One system acts as an Ethernet AVB audio endpoint device and another system acts as an audio gateway between IEEE 1394 and Ethernet AVB networks. These systems, along with existing IEEE 1394 audio devices, were used to demonstrate the ability to transfer audio data between the networking technologies. Each of the devices is remotely controllable via a network neutral command and control protocol, XFN. The IEEE 1394 and Ethernet AVB devices are used to demonstrate the use of the XFN protocol to allow for network neutral connection management to take place between IEEE 1394 and Ethernet AVB networks. User control over these diverse devices is achieved via the use of a graphical patchbay application, which aims to provide a consistent user interface to a diverse range of devices.
15

The effect of computer mediated communication to communication patterns

Methawut, Elena 01 January 2004 (has links)
Computer mediated communication (CMC) fundamentally influences the function of communication. It influences the organization's management and administration, but it most affects the dynamics of middle and lower level employees. The most simplistic model is that of an electronic office in which its employees need to know and understand the role of CMC. The purpose of this study is to investigate the performance and satisfaction of co-workers who use CMC to communicate within their organization, and to check employees' performance when using CMC.
16

Performance evaluation of routing protocols using NS-2 and realistic traces on driving simulator

Chen, Mingye 21 May 2014 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / With the rapid growth in wireless mobile communication technology, Vehicular Ad-hoc Network (VANET) has emerged as a promising method to effectively solve transportation-related issues. So far, most of researches on VANETs have been conducted with simulations as the real-world experiment is expensive. A core problem affecting the fidelity of simulation is the mobility model employed. In this thesis, a sophisticated traffic simulator capable of generating realistic vehicle traces is introduced. Combined with network simulator NS-2, we used this tool to evaluate the general performance of several routing protocols and studied the impact of intersections on simulation results. We show that static nodes near the intersection tend to become more active in packet delivery with higher transferred throughput.

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