Dissertations / Theses on the topic 'Data Communications'
To see the other types of publications on this topic, follow the link: Data Communications.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Data Communications.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Lo, Kam Chuen. "Encoding strategies for data communications." Thesis, University of Sunderland, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310619.
Full text
2
Amornraksa, Thumrongrat. "Data security for multimedia communications." Thesis, University of Surrey, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298091.
Full text
3
Strock, O. J. (Jud), and Michael (Mike) Witchey. "TELEMETRY DATA VIA COMMUNICATIONS RELAY." International Foundation for Telemetering, 1990. http://hdl.handle.net/10150/613788.
Full textAbstract:
International Telemetering Conference Proceedings / October 29-November 02, 1990 / Riviera Hotel and Convention Center, Las Vegas, NevadaThis paper responds to a test range engineer’s need to relay one or more channels of various types of telemetry data from a remotely-located receiving station to the central telemetry station at range headquarters for real time processing and display. Several types of data are identified, and specific equipment and technology for multiplexing, transmission, and demultiplexing up to eight streams from a variety of sources is discussed. The widely-used T3 communications link, also known as DS-3, can relay data via satellite, microwave link, or other high-speed path at 44.736 megabits per second, of which about 95% can be actual telemetry data; other standard links operate at lower aggregate rates. Several links and rates are discussed, with emphasis in the high-rate T3 link.
4
Tian, Hai, Tom Trojak, and Charles Jones. "DATA COMMUNICATIONS OVER AIRCRAFT POWER LINES." International Foundation for Telemetering, 2005. http://hdl.handle.net/10150/604922.
Full textAbstract:
ITC/USA 2005 Conference Proceedings / The Forty-First Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2005 / Riviera Hotel & Convention Center, Las Vegas, NevadaThis paper introduces a study of the feasibility and initial hardware design for transmitting data over aircraft power lines. The intent of this design is to significantly reduce the wiring in the aircraft instrumentation system. The potential usages of this technology include Common Airborne Instrumentation System (CAIS) or clock distribution. Aircraft power lines channel characteristics are presented and Orthogonal Frequency Division Multiplexing (OFDM) is introduced as an attractive modulation scheme for high-speed power line transmission. A design of a full-duplex transceiver with accurate frequency planning is then discussed. A general discussion of what communications protocols are appropriate for this technology is also provided.
5
FEARING, CHRISTOPHER JAMES. "IMAGING SENSORS WITH DATA COMMUNICATIONS CAPABILITIES." University of Cincinnati / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1141352420.
Full text
6
Gonçalves, João Miguel Ribeiro. "Context-awareness privacy in data communications." Doctoral thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/15760.
Full textAbstract:
Doutoramento em InformáticaInternet users consume online targeted advertising based on information collected about them and voluntarily share personal information in social networks. Sensor information and data from smart-phones is collected and used by applications, sometimes in unclear ways. As it happens today with smartphones, in the near future sensors will be shipped in all types of connected devices, enabling ubiquitous information gathering from the physical environment, enabling the vision of Ambient Intelligence. The value of gathered data, if not obvious, can be harnessed through data mining techniques and put to use by enabling personalized and tailored services as well as business intelligence practices, fueling the digital economy. However, the ever-expanding information gathering and use undermines the privacy conceptions of the past. Natural social practices of managing privacy in daily relations are overridden by socially-awkward communication tools, service providers struggle with security issues resulting in harmful data leaks, governments use mass surveillance techniques, the incentives of the digital economy threaten consumer privacy, and the advancement of consumergrade data-gathering technology enables new inter-personal abuses. A wide range of fields attempts to address technology-related privacy problems, however they vary immensely in terms of assumptions, scope and approach. Privacy of future use cases is typically handled vertically, instead of building upon previous work that can be re-contextualized, while current privacy problems are typically addressed per type in a more focused way. Because significant effort was required to make sense of the relations and structure of privacy-related work, this thesis attempts to transmit a structured view of it. It is multi-disciplinary - from cryptography to economics, including distributed systems and information theory - and addresses privacy issues of different natures. As existing work is framed and discussed, the contributions to the state-of-theart done in the scope of this thesis are presented. The contributions add to five distinct areas: 1) identity in distributed systems; 2) future context-aware services; 3) event-based context management; 4) low-latency information flow control; 5) high-dimensional dataset anonymity. Finally, having laid out such landscape of the privacy-preserving work, the current and future privacy challenges are discussed, considering not only technical but also socio-economic perspectives.
Quem usa a Internet vê publicidade direccionada com base nos seus hábitos de navegação, e provavelmente partilha voluntariamente informação pessoal em redes sociais. A informação disponível nos novos telemóveis é amplamente acedida e utilizada por aplicações móveis, por vezes sem razões claras para isso. Tal como acontece hoje com os telemóveis, no futuro muitos tipos de dispositivos elecónicos incluirão sensores que permitirão captar dados do ambiente, possibilitando o surgimento de ambientes inteligentes. O valor dos dados captados, se não for óbvio, pode ser derivado através de técnicas de análise de dados e usado para fornecer serviços personalizados e definir estratégias de negócio, fomentando a economia digital. No entanto estas práticas de recolha de informação criam novas questões de privacidade. As práticas naturais de relações inter-pessoais são dificultadas por novos meios de comunicação que não as contemplam, os problemas de segurança de informação sucedem-se, os estados vigiam os seus cidadãos, a economia digital leva á monitorização dos consumidores, e as capacidades de captação e gravação dos novos dispositivos eletrónicos podem ser usadas abusivamente pelos próprios utilizadores contra outras pessoas. Um grande número de áreas científicas focam problemas de privacidade relacionados com tecnologia, no entanto fazem-no de maneiras diferentes e assumindo pontos de partida distintos. A privacidade de novos cenários é tipicamente tratada verticalmente, em vez de re-contextualizar trabalho existente, enquanto os problemas actuais são tratados de uma forma mais focada. Devido a este fraccionamento no trabalho existente, um exercício muito relevante foi a sua estruturação no âmbito desta tese. O trabalho identificado é multi-disciplinar - da criptografia à economia, incluindo sistemas distribuídos e teoria da informação - e trata de problemas de privacidade de naturezas diferentes. À medida que o trabalho existente é apresentado, as contribuições feitas por esta tese são discutidas. Estas enquadram-se em cinco áreas distintas: 1) identidade em sistemas distribuídos; 2) serviços contextualizados; 3) gestão orientada a eventos de informação de contexto; 4) controlo de fluxo de informação com latência baixa; 5) bases de dados de recomendação anónimas. Tendo descrito o trabalho existente em privacidade, os desafios actuais e futuros da privacidade são discutidos considerando também perspectivas socio-económicas.
7
Li, Huanlu. "Integrated photonic devices for data communications." Thesis, University of Bristol, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.682683.
Full textAbstract:
With the increasing capacity requirements of telecommunication systems, the ability to increase capacity density is of great importance for optical transmission technologies. This thesis presents several integrated photonic devices (semiconductor laser diodes and silicon devices) aimed at boosting the capacity density of the optical transmission systems. The first part of the thesis is about four wave mixing (FWM) effects in semiconductor ring lasers. Mode beating via third order nonlinearity in semiconductor ring lasers has been analysed using a frequency-domain multi-mode rate equation model. Compared with Fabry-Perot lasers, semiconductor ring lasers are found to be 1.33, 2, and 4 times more efficient in self-gain compression, cross-gain compression and four-wave mixing processes, respectively, due to its travelling-wave nature. It is shown that, using dual (pump and signal) external optical injections into the ring laser cavity, multiple modes can be locked in phase via the strong four wave mixing phenomenon. This results in modulation of the light wave at the mode beating frequencies which could be used for RF optical catrier generation. Secondly, following Bristol's research on compact optical vortex beam emitter based on silicon photonic micro-ring resonators, a different approach is demonstrated to simultaneously generate a pair of orbital angular momentum (OAM) modes with opposite topological charge by integrating a micro-ring OAM resonator with simple waveguide devices. The relative phase between two vortices can be actively modulated on the chip by thermo-optical controls. Furthermore, based on the ring cavity structure, OAM ring lasers on AlGaInAs/InP wafer are also developed. Detailed designs, fabrication processes and characterization of the device are discussed. In the last part of the thesis, a new approach is to propose and demonstrate directly generated optical OAM beams, by integrating a micro-scale spiral phase plate (SPP) on top of a vertical-cavity surface-emitting laser (VCSEL). The presence of the multi-level SPP transforms the linearly polarized Gaussian beam to a beam carrying specific OAM modes and their superposition states. The emitted OAM beams are characterized by usmg a spatial light modulator (SLM), and show good agreement with semi-analytical numerical simulation. The innovative OAM emitter opens a new horizon in the field of OAM-based optical and quantum communications, especially for low-cost short reach interconnects.
8
Chan, Christopher Wing Tai. "Magneto-inductive wave data communications systems." Thesis, University of Oxford, 2014. https://ora.ox.ac.uk/objects/uuid:014605c8-fc15-4166-a382-695042b05312.
Full textAbstract:
Metamaterials display unusual electromagnetic properties, such as, a negative effective permeability and negative effective permittivity. This has sparked much interest due to possibility of negative refraction which was later confirmed by experiments. The ability of magnetically coupled resonant circuits to display an effective permeability lead to the discovery of magneto-inductive waves. These waves are only supported on arrays of magnetically coupled resonant circuits. Research into magneto-inductive waves has been largely concentrated on their use in filters and their potential use in magnetic resonance imaging. However, some work has proposed the use of magneto-inductive waveguides as a data transfer medium. This report builds on previous work which found that an optimum existed for terminal-waveguide coupling, and aims to investigate the application of magneto-inductive waves in data transfer systems. A brief overview of the topic is given along with a description of the underlying characteristics. Factors that affect the capacity of magneto-inductive wave data transfer systems, such as inter element coupling, were identified. Two novel structures, both with the intent of increasing the bandwidth via different methods, are studied. One, by making a pseudo one-dimensional channel from a two-dimensional structure, and the other by using a dual-layer design to increase the coupling between adjacent elements. Both systems are modelled, using simple circuit theory and the impedance matrix method, and a comparison between simulated behaviour and experimental observation was made. There is discussion about the differences between experiment and simulation as well as their limitations. Magneto-inductive wave data transfer systems are eventually expected to support multiple terminals and as previous research only considered two-terminal systems, an investigation into the response of a one- and two-dimensional system with a blocking terminal was undertaken. The system was modelled, again using simple circuit theory and the impedance matrix method, and simulation and experiment were compared. As a whole, the simulations showed good agreement with experiments, after some initial adjustments. Both one- and two-dimensional systems showed that their performance was not severely effected by a blocking terminal. This suggests that magneto-inductive waveguides could support more terminals.
9
Fleet, Daniel. "Visualization of data communications in three dimensions." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ38374.pdf.
Full text
10
Singh, Manvinder. "Multi-variate adaptive protocols for data communications." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0021/MQ46276.pdf.
Full text
11
Xiao, Shengkuan. "Advances in image modeling and data communications." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 132 p, 2007. http://proquest.umi.com/pqdweb?did=1331413801&sid=6&Fmt=2&clientId=8331&RQT=309&VName=PQD.
Full text
12
Palmquist, Fredrik. "Satellite data communications as acomplement to GSM." Thesis, KTH, Teleinformatik, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-93580.
Full textAbstract:
The use of mobile Internet has reached the transport industry. Internet will be used to transport important and security-critical information from and to vehicles. Using Internet in this context raises a severe problem. Only 6% of the world is covered by GSM, the primary Internet bearer for mobile usage. The subject of this thesis is to explore suitable backups in order to provide the user with global coverage for important information exchange. The messages to send and receive are small in size, often less than 100 bytes. The time factor of the transmission is important, an alert message often has to be passed within minutes to be of any use. These factors together with the global coverage leave us with only one suitable solution, a satellite data communication system. The first part of this thesis contains an investigation of the satellite communication market. Two different systems, Inmarsat-C and ORBCOMM, are chosen for further study and evaluation. One Inmarsat-C unit and two ORBCOMM units are found suitable for the application. The last part of the thesis contains the evaluation, testing and system integration of these units. The conclusion is that ORBCOMM, although not yet fully developed, has the capabilities and performance necessary for use in a mobile environment such as a truck. The two different ORBCOMM units tested, Panasonic and Stellar, were found to have comparable qualities.
13
Bennecer, Abdeldjalil. "Low cost integrated lasers for data communications." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609254.
Full text
14
Dapore, Mark. "High Data Rate X-Band Communications Subsystem." International Foundation for Telemetering, 1995. http://hdl.handle.net/10150/611617.
Full textAbstract:
International Telemetering Conference Proceedings / October 30-November 02, 1995 / Riviera Hotel, Las Vegas, NevadaA Communication Subsystem has been developed capable of 25 Megasymbol per Second (MSPS) data rates. The unit operates in the 8300 to 8400 MHz band and uses shaped QPSK for excellent spectral containment properties. The Communication Subsystem (CSS) has a number of features which make it attractive for many applications: (1) Data is convolutionally encoded inside the transmitter resulting in excellent link performance without using external hardware. (2) Data is encrypted inside the transmitter. The DES standard is currently implemented, however, military encryption is an option which requires minimal changes in the CSS design. (3) Frame Synchronization Sequences and Block Identification Numbers are inserted into the data by the CSS. (4) Cyclic Redundancy Checked Codes for each data block are generated within the CSS. (5) Health and Status of the CSS is formatted into digital words. (6) Mode Control, Key Maintenance, and Health and Status Reporting is easily handled through an RS-422 interface. (7) The CSS is ruggedized for launch environments and is highly reliable for space applications.
15
Zyambo, Emmanuel Baleke. "High-speed wireless infrared communications." Thesis, University of Oxford, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.275377.
Full text
16
Hum, Eddy N. (Eddy Ning) Carleton University Dissertation Engineering Electrical. "Burst-trapping codes for the land mobile data channel." Ottawa, 1988.
Find full text
17
Clapp, T. C. "Statistical methods for the processing of communications data." Thesis, University of Cambridge, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.597697.
Full textAbstract:
This thesis describes the use of methods derived from Bayesian statistics on the problem of blind equalisation of communications channels, although much of this work is applicable to the more general problem of blind deconvolution. In order to allow general models to be incorporated, numerical methods are used; the focus is on Markov chain Monte Carlo (MCMC) methods for processing of blocks of data and the use of particle filters for sequential processing. In order to obtain the best performance using MCMC, the choice of the Markov chain needs tailoring to the application in hand. The use of joint sampling of all the states (transmitted data sequence) and reversible jump moves to combat delay ambiguity are proposed. The use of particle filters is still in its infancy, and much of the focus is on the development of strategies to improve its applicability to real problems. It is well known that fixed-lag methods may be used to great effect on Markovian models where later observations can provide information about states in the recent past. Methods of performing fixed-lag simulation for incorporation into particle filters are described. The use of data windowing on fixed parameter systems allows regeneration of the parameters at each time-step without having excessive demands on storage requirements. In certain cases it is difficult to perform the updating when a new data point is received in a single step. The novel concept of introducing intermediate densities in a manner akin to simulated annealing between time steps is described. This improves robustness and provides a natural method for initialisation. All of these techniques are demonstrated in simulations based upon standard models of communications systems, along with favourable comparisons to more conventional techniques.
18
Onochie, Francis Chukwuemeka. "Digital data communications over voice-band telephone channels." Thesis, Imperial College London, 1989. http://hdl.handle.net/10044/1/47598.
Full text
19
Economou, Emmanuel. "How institutional pressures influence data-driven corporate communications." Thesis, Queensland University of Technology, 2021. https://eprints.qut.edu.au/209153/1/Emmanuel_Economou_Thesis.pdf.
Full textAbstract:
This study explores the use of data to guide corporate communications, a practice of which empirical research is limited, and is the first to investigate how institutional pressures influence practitioners in their work. In-depth interviews were conducted with 15 participants from a wide range of organisations in Brisbane, Australia. Additionally, the study illustrates the current state of research on big data in corporate communication in a systematic literature review. The study’s findings indicate that institutional pressures influence data-driven corporate communications and are generally consistent with the results of practitioner studies around the world.
20
Qureshi, Zihad. "Vertical cavity surface emitting lasers in high speed optical data communications." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.608126.
Full text
21
Laaboudi, Younes. "Reactive security of IoT communications." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-249633.
Full textAbstract:
IoT networks’ intrinsic vulnerabilities can be protected through intru- sion detection and response systems (IDRS). Anomaly-based intrusion detection offers multiple advantages: it can detect unknown attacks and it can adapt to multiple types of protocols. However, intrusion response is harder to carry out in combination with an anomaly-based detection system in part due to the possibility of false positive alerts. Through two implementations of IDRS in two distinct IoT networks, this thesis will highlight ways to improve anomaly-based detection and allow for appropriate response when possible. The results show that anomaly-based detection can be used in the case of a ZigBee IoT network to detect different types of attacks without previous knowl- edge of these attacks. Moreover, soft response methods that improve the quality of detection with a low impact on the IoT network behavior are achievable.IoT-nätverks sårbarheter kan skyddas genom intrångsdetektering och svarsystem (IDRS). Anomalibaserad intrångsdetektering erbjuder flera fördelar: det kan upptäcka okända attacker och det kan anpassa sig till flera typer av protokoll. Inbrottssvaret är svårare att genomföra i kombination med ett anomalibaserat detekteringssystem, delvis på grund av möjligheten till falska positiva varningar. Det här exjobbet söker sätt att förbättra anomalibaserad detektering och svar genom två implementeringar av IDRS i två distinkta IoT-nätverk. Resultaten visar att anomalibaserad detektering kan användas vid ett ZigBee IoT- nätverk för att upptäcka olika typer av attacker utan tidigare kunskaper om den här attackerna. Dessutom kan mjuka svarmetoder användas för att förbättrar detekteringskvaliteten med låg inverkan på IoT- nätverksbeteendet.
22
Skidmore, Roger Ray. "A Comprehensive Method and System for the Design and Deployment of Wireless Data Networks." Diss., Virginia Tech, 2003. http://hdl.handle.net/10919/27611.
Full textAbstract:
Increasingly, wireless subscribers are demanding reliable data capabilities from wireless networks. The ability of wireless network engineers and Information Technology (IT) professionals to rapidly design, deploy, and maintain wireless communication systems that can provide strong, reliable data service is severely hampered by a lack of adequate systems and methods for simulating the performance of such networks a priori. Unlike older generation wireless systems that could be readily deployed on the basis of strong received signal strength and simple circuit-switched channel allocation protocols, modern and emerging wireless data networks are more noise and interference limited and rely on packet-based protocols. A heavier emphasis is needed on predicting and simulating throughput, bit error rate, frame error rate, user priority classes, and overall network capacity. This research provides wireless network engineers and IT professionals with a comprehensive system and method for the simulation and design of wireless communication systems that combines site-specific databases, equipment-specific distribution system modeling, and advanced ray tracing propagation analysis to directly predict throughput, frame error rate (FER), and other critical performance parameters for emerging wireless data networks.Ph. D.
23
Yao, Li-Jun. "Real-time communications in token ring networks." Title page, abstract and contents only, 1994. http://web4.library.adelaide.edu.au/theses/09PH/09phy248.pdf.
Full text
24
Argon, Cenk. "Turbo product codes for optical communications and data storage." Diss., Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/15350.
Full text
25
Walden, Ian Newark. "Data communications security : legislating and contracting for legal security." Thesis, Nottingham Trent University, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314417.
Full text
26
Topham, Debra Ann. "Decentralised wireless data dissemination for vehicle-to-vehicle communications." Thesis, University of Birmingham, 2012. http://etheses.bham.ac.uk//id/eprint/3335/.
Full textAbstract:
This thesis is concerned with inter-vehicle communications supporting the deployment of future safety-related applications. Through use case analysis of the specific communica- tions requirements of safety related and traffic efficiency applications, a data dissemination framework is proposed that is able to meet the various message delivery requirements. More specifically, this thesis focuses on the subset of the proposed framework, which provides geocasting, i.e. addressing a geographical area on the road network, and local zone connectivity, providing neighbour awareness, for safety related applications. The enabling communications technology for inter-vehicle communications based on IEEE 802.11 wireless local area network devices and the associated lack of reliability it presents for the distribution of safety messages in broadcast mode, form the main topic of this thesis. A dissemination scheme for safety related inter-vehicular communication applica- tions, using realistic vehicular traffic patterns, is proposed, implemented and evaluated to demonstrate mechanisms for efficient, reliable and timely delivery of safety messages over an unreliable channel access scheme. The original contribution of this thesis is to propose a novel data dissemination protocol for vehicular environments, capable of simultaneously achieving significant economy of messaging, whilst maintaining near 100% reliable message delivery in a timely manner for a wide variety of highway traffic flow scenarios, ranging from sparsely, fragmented networks to dense, congested road networks. This is achieved through increased protocol complexity in inferring and tracking each vehicular node’s local environment, coupled with implementing adaptation to both local data traffic intensity and vehicular density. Adaptivity is achieved through creating and employing an empirical channel access delay model and embedding the stochastic delay distribution in decisions made at the network layer; this method of adaptivity is novel in itself. Moreover, unnecessary retransmissions arising from the inherent uncertainty of the wireless medium are suppressed through a novel three-step mechanism.
27
Watkins, Stan M. "FLEXIBLE SECURE DATA COMMUNICATIONS WITH THE RANGE ENCRYPTION MODULE." International Foundation for Telemetering, 1999. http://hdl.handle.net/10150/608536.
Full textAbstract:
International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, NevadaThis paper discusses the design, application and flexibility of the Range Encryption Module (REM) developed by L3 Communications Conic Division for the Range Application Joint Program Office (RAJPO) located at Eglin Air Force Base in Florida. The REM is a burst encrypter that utilizes the National Security Agency Thornton CTIC/DS- 101 Hybrid (CDH) encryption algorithm. The CDH device operates under the control of a Conic-designed digital ASIC. The CDH, ASIC, Power Management and parallel bus interface circuits reside on a single card within the REM called the Common Encryption Core (CEC). The REM and CEC card within the REM offer flexibility in many operational features, as described below.
28
Gozali, Ran. "Space-Time Codes for High Data Rate Wireless Communications." Diss., Virginia Tech, 2002. http://hdl.handle.net/10919/27193.
Full textAbstract:
Space-time codes (STC) are a class of signaling techniques, offering coding and diversity gains along with improved spectral efficiency. These codes exploit both the spatial and the temporal diversity of the wireless link by combining the design of the error correction code, modulation scheme and array processing. STC are well suited for improving the downlink performance, which is the bottleneck in asymmetric applications such as downstream Internet.
Three original contributions to the area of STC are presented in this dissertation. First, the development of analytic tools that determine the fundamental limits on the performance of STC in a variety of channel conditions. For trellis-type STC, transfer function based techniques are applied to derive performance bounds over Rayleigh, Rician and correlated fading environments. For block-type STC, an analytic framework that supports various complex orthogonal designs with arbitrary signal cardinalities and array configurations is developed. In the second part of the dissertation, the Virginia Tech Space-Time Advanced Radio (VT-STAR) is designed, introducing a multi-antenna hardware laboratory test bed, which facilitates characterization of the multiple-input multiple-output (MIMO) channel and validation of various space-time approaches. In the third part of the dissertation, two novel space-time architectures paired with iterative processing principles are proposed. The first extends the suitability of STC to outdoor wireless communications by employing iterative equalization/decoding for time dispersive channels and the second employs iterative interference cancellation/decoding to solve the error propagation problem of Bell-Labs Layered Space-Time Architecture (BLAST). Results show that remarkable energy and spectral efficiencies are achievable by combining concepts drawn from space-time coding, multiuser detection, array processing and iterative decoding.Ph. D.
29
Ben, Mahmoud Mohamed Slim. "Addressing Security Challenges in Emerging Data-based Aeronautical Communications." Thesis, Toulouse, INSA, 2012. http://www.theses.fr/2012ISAT0006/document.
Full textAbstract:
Ce travail de thèse s'intéresse à la sécurité des futures communications aéronautiques de donnée. Le travail est divisé en trois grandes parties. La première contribution est une architecture de sécurité adaptative pour les communications aéronautiques intégrant un segment sol-bord par satellite. Un module de gestion de la sécurité a été conçu, développé, puis validé lors de la phase finale d'intégration du projet FAST (Fibre-like Aircraft Satellite Communications). La deuxième contribution est une méthodologie quantitative d'estimation du risque lié à la sécurité réseau. L'originalité de notre approche est d'être basée sur la notion de propagation du risque au sein des différents noeuds du réseau. Commecas d'étude, un réseau de communication aéroportuaire utilisant le protocole AeroMACS a été étudié dans le cadre du projet SESAR (Single European Sky ATM Research). La troisième contribution est une infrastructure à clés publiques (PKI) qui permet d'optimiser les échanges de signalisation (échanges de clés, certificats, vérification des signatures) entre l'avion et l'autorité de certification au sol. Le modèle de PKI proposé est un modèle hiérarchique utilisant la certification croisée entre les autorités de certification mèresThis research work deals with the information and network security in the aeronautical communication domain. Three fundamental research axes are explored. First, a quantitative network security risk assessment methodology is proposed. Our approach is based on the risk propagation within the network nodes. As study cases, the algorithm has been validated in the scope of the European industrial project entitled SESAR (Single European Sky ATM Research) and the Aerospace Valley FAST (Fibrelike Aircraft Satellite Communications). Particularly, experimental results relative to the case study devoted to the FAST project shown that the global network risk in the non secured system architecture is relatively high, meaning the system needs more consideration from a security point of view. To cope with this issue, an adaptive security management framework for a satellite-based aeronauticalcommunication architecture has been proposed as a second contribution. A security manager module has been designed, implemented, then tested in the scope of the FAST project. Finally, as the security primitives used in the adaptive security management framework need to be efficiently exchanged, the last contribution consists in a scalable PKI adapted for the upcoming network-enabled aircraft. The idea is to minimize the air-ground additional overhead induced by the security procedures (keys, digital certificates, revocation/verification procedures). The PKI model we propose is a cross-certified multirooted hierarchical model
30
SENIGAGLIESI, LINDA. "Information-theoretic security techniques for data communications and storage." Doctoral thesis, Università Politecnica delle Marche, 2019. http://hdl.handle.net/11566/263165.
Full textAbstract:
Negli ultimi anni il bisogno di sicurezza e privacy è cresciuto in maniera esponenziale in molti aspetti delle comunicazioni, parallelamente allo sviluppo tecnologico. La maggior parte dei sistemi di sicurezza attualmente implementati sono basati sulla nozione di sicurezza computazionale, e devono essere continuamente tenuti aggiornati per affrontare il miglioramento degli attacchi e l’avanzamento tecnologico. Allo scopo di soddisfare requisiti sempre più stringenti e rigorosi, di recente è cresciuto l’interesse verso soluzioni appartenenti al paradigma della teoria dell’informazione a supporto di schemi di segretezza prettamente crittografici, in particolare grazie alla capacità di queste soluzioni di garantire sicurezza indipendentemente dalla capacità dell’attaccante, altrimenti nota come sicurezza incondizionata. In questo lavoro di tesi il nostro scopo è quello di analizzare come metriche di segretezza relative alla teoria dell’informazione possono essere applicate in sistemi pratici con lo scopo di garantire la sicurezza e la privacy dei dati.
Per iniziare, vengono definite delle metriche di tipo information-teoretiche per valutare le prestazioni di segretezza di sistemi realistici di comunicazione wireless sotto vincoli pratici, e con esse un protocollo che combina tecniche di codifica per sicurezza a livello fisico con soluzioni crittografiche. Questo schema è in grado di raggiungere un dato livello di sicurezza semantica in presenza di un attaccante passivo. Allo stesso tempo vengono presi in considerazione molteplici scenari: viene fornita un’analisi di sicurezza per canali paralleli con nodi relay, trovando l’allocazione ottima di risorse che massimizza il secrecy rate. Successivamente, sfruttando un model checker probabilistico, vengono definiti i parametri per sistemi di storage distribuiti ed eterogenei che permettono di raggiungere la segretezza perfetta in condizioni pratiche. Per garantire la privacy, proponiamo inoltre uno schema che garantisce il recupero privato delle informazioni in uno scenario di caching wireless in presenza di nodi malevoli. Definiamo infine il piazzamento ottimale dei contenuti tale minimizzare l’uso del canale di backhaul, riducendo così il costo delle comunicazioni del sistema.The last years have seen a growing need of security and privacy in many aspects of communications, together with the technological progress. Most of the implemented security solutions are based on the notion of computational security, and must be kept continuously updated to face new attacks and technology advancements. To meet the more and more strict requirements, solutions based on the information-theoretic paradigm are gaining interest to support pure cryptographic techniques, thanks to their capacity to achieve security independently on the attacker’s computing resources, also known as unconditional security. In this work we investigate how information-theoretic security can be applied to practical systems in order to ensure data security and privacy. We first start defining information-theoretic metrics to assess the secrecy performance of realistic wireless communication settings under practical conditions, together with a protocol that mixes coding techniques for physical layer security and cryptographic solutions. This scheme is able to achieve some level of semantic security at the presence of a passive attacker. At the same time, multiple scenarios are considered. We provide a security analysis for parallel relay channels, thus finding an optimal resource allocation that maximizes the secrecy rate. Successively, by exploiting a probabilistic model checker, we define the parameters for heterogeneous distributed storage systems that permit us to achieve perfect secrecy in practical conditions. For privacy purposes, we propose a scheme which guarantees private information retrieval of files for caching at the wireless edge against multiple spy nodes. We find the optimal content placement that minimizes the backhaul usage, thus reducing the communication cost of the system.
31
Davies, Mark Anthony. "Waveform regeneration of voiceband data signals." Thesis, University of Liverpool, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284259.
Full text
32
Dhomeja, Sheyam Lal. "CDMA communications over wireless infrared channels." Thesis, University of Southampton, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287004.
Full text
33
Delaplace, Franck. "Compilation des communications dans un langage data-parallèle pour les architectures à réseau à communications compilées." Paris 11, 1994. http://www.theses.fr/1994PA112168.
Full textAbstract:
Dans les architectures multiprocesseurs à mémoire distribuée, les communications sont traditionnellement considérées comme plus pénalisantes qu'un calcul. Un des facteurs principaux de ce déséquilibre entre les calculs et les communications doit être imputé au modèle de communication à passage de messages, et en particulier aux couches logicielles réalisant le routage d'un message. A l'opposé, le modèle à communications compilées, tel que celui de la machine Ptah du lri, mais aussi du gf11, nécessite une détermination préalable des chemins, qui s'effectue lors de la phase de compilation. Les éléments gérés par le compilateur concernent alors la définition des chemins, ainsi que la gestion des paquets de messages. La partie traitée lors de l'exécution se réduit donc au transfert des données. La compilation se décompose en deux étapes: définir un programme de communication sur chaque processeur, ce qui constitue la compilation des communications ; définir l'allocation des ressources matérielles du réseau, c'est la compilation du routage. Dans cette thèse, nous avons défini les outils théoriques et les techniques permettant l'analyse et la compilation des communications. Ces techniques ont été développées pour un noyau significatif du langage data-parallèle high performance Fortran. Nous avons insisté sur le développement des techniques spécifiques à une architecture basée sur le principe des réseaux à communications compilées, à savoir la génération d'un code permettant une exécution synchrone et la gestion efficace des schémas de communications. Nous avons validé la compilation des communications par le développement d'un compilateur d'un noyau de hpf nomme high performance Tiny pour l'architecture ptah. L'étude des différents points (analyse des communications, génération de code et compilation du routage) démontre que sous certaines contraintes concernant le placement, la compilation des communications est une alternative valide au routage dynamique par passage de messages
34
Zhou, Yiqing, and 周一靑. "Advanced techniques for high speed wireless communications." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B29296080.
Full text
35
See, Chong Meng Samson. "Space-time processing for wireless mobile communications." Thesis, Loughborough University, 1999. https://dspace.lboro.ac.uk/2134/25284.
Full textAbstract:
Intersymbol interference (ISI) and co-channel interference (CCI) are two major obstacles to high speed data transmission in wireless cellular communications systems. Unlike thermal noise, their effects cannot be removed by increasing the signal power and are time-varying due to the relative motion between the transmitters and receivers. Space-time processing offers a signal processing framework to optimally integrate the spatial and temporal properties of the signal for maximal signal reception and at the same time, mitigate the ISI and CCI impairments. In this thesis, we focus on the development of this emerging technology to combat the undesirable effects of ISI and CCL We first develop a convenient mathematical model to parameterize the space-time multipath channel based on signal path power, directions and times of arrival. Starting from the continuous time-domain, we derive compact expressions of the vector space-time channel model that lead to the notion of block space-time manifold, Under certain identifiability conditions, the noiseless vector-channel outputs will lie on a subspace constructed from a set. of basis belonging to the block space-time manifold. This is an important observation as many high resolution array processing algorithms Can be applied directly to estimate the multi path channel parameters. Next we focus on the development of semi-blind channel identification and equalization algorithms for fast time-varying multi path channels. Specifically. we develop space-time processing algorithms for wireless TDMA networks that use short burst data formats with extremely short training data. sequences. Due to the latter, the estimated channel parameters are extremely unreliable for equalization with conventional adaptive methods. We approach the channel acquisition, tracking and equalization problems jointly, and exploit the richness of the inherent structural relationship between the channel parameters and the data sequence by repeated use of available data through a forward- backward optimization procedure. This enables the fuller exploitation of the available data. Our simulation studies show that significant performance gains are achieved over conventional methods. In the final part of this thesis, we address the problem identifying and equalizing multi path communication channels in the presence of strong CCl. By considering CCI as stochasic processes, we find that temporal diversity can be gained by observing the channel outputs from a tapped delay line. Together with the assertion that the finite alphabet property of the information sequences can offer additional information about the channel parameters and the noise-plus-covariance matrix, we develop a spatial temporal algorithm, iterative reweighting alternating minimization, to estimate the channel parameters and information sequence in a weighted least squares framework. The proposed algorithm is robust as it does not require knowledge of the number of CCI nor their structural information. Simulation studies demonstrate its efficacy over many reported methods.
36
McGinty, Nigel, and nigel mcginty@defence gov au. "Reduced Complexity Equalization for Data Communication." The Australian National University. Research School of Information Sciences and Engineering, 1998. http://thesis.anu.edu.au./public/adt-ANU20050602.122741.
Full textAbstract:
Optimal decision directed equalization techniques for time dispersive communication channels are often too complex to implement. This thesis considers reduced complexity decision directed equalization that lowers complexity demands yet retains close to optimal performance. The first part of this dissertation consists of three reduced complexity algorithms based on the Viterbi Algorithm (VA) which are: the Parallel Trellis VA (PTVA); Time Reverse Reduced State Sequence Estimation (TR-RSSE); and Forward-Backward State Sequence Detection (FBSSD). The second part of the thesis considers structural modifications of the Decision Feedback Equalizer (DFE), which is a special derivative of the VA, specifically, optimal vector quantization for fractionally spaced DFEs, and extended stability regions for baud spaced DFEs using passivity analysis are investigated.¶
For a special class of sparse channels the VA can be decomposed over a number of independent parallel trellises. This decomposition will be called the Parallel Trellis Viterbi Algorithm and can have lower complexity than the VA yet it retains optimal performance. By relaxing strict sparseness constraints on the channel a sub-optimal approach is proposed which keeps complexity low and obtains good performance.¶
Reduced State Sequence Estimation (RSSE) is a popular technique to reduce complexity. However, its deficiency can be the inability to adequately equalize non-minimum phase channels. For channels that have energy peaks in the tail of the impulse response (post-cursor dominant) RSSE's complexity must be close to the VA or performance will be poor. Using a property of the VA which makes it invariant to channel reversal, TR-RSSE is proposed to extend application of RSSE to post-cursor dominant channels.¶
To further extend the class of channels suitable for RSSE type processing, FBSSD is suggested. This uses a two pass processing method, and is suited to channels that have low energy pre and post-cursor. The first pass generates preliminary estimates used in the second pass to aid the decision process. FBSSD can range from RSSE to TR-RSSE depending on parameter settings.¶
The DFE is obtained when the complexity of RSSE is minimized. Two characterizing properties of the DFE, which are addressed in this thesis, are feedback and quantization. A novel fractionally spaced (FS) DFE structure is presented which allows the quantizer to be generalized relative to the quantizer used in conventional FS-DFEs. The quantizer can be designed according to a maximum a posteriori criterion which takes into account a priori statistical knowledge of error occurrences. A radically different quantizer can be obtained using this technique which can result in significant performance improvements.¶
Due to the feedback nature of the DFE a form of stability can be considered. After a decision error occurs, a stable DFE will, after some finite time and in the absence of noise, operate error free. Passivity analysis provides sufficient conditions to determine a class of channels which insures a DFE will be stable. Under conditions of short channels and small modulation alphabets, it is proposed that conventional passivity analysis can be extended to account for varying operator gains, leading to weaker sufficient conditions for stability (larger class of channels).
37
Thomas, Charalambos Bob. "Information communications technologies in education : a Faustian bargain?" Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33934.
Full textAbstract:
There is currently a glaring absence of critical discourse surrounding the integration of information communications technologies in schools. Despite a growing body of literature showing that technology has both advantages and disadvantages, schools are incorporating ICT as if it were a panacea for educational and societal ills. This deification of ICT is based on utilitarian concerns and spiritual yearnings. The first chapter situates the author and outlines how the larger technology metanarrative has a mythic status. Chapter two situates the appeal to utilitarian and spiritual values in the wider culture. The final chapter examines how these issues are played out in the school system. The author concludes with a summary and raises areas for further investigation, along with suggestions for change.
38
Alfredsson, Anders. "XML as a Format for Representation and Manipulation of Data from Radar Communications." Thesis, University of Skövde, Department of Computer Science, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-591.
Full textAbstract:
XML was designed to be a new standard for marking up data on the web. However, as a result of its extensible and flexible properties, XML is now being used more and more for other purposes than was originally intended. Today XML is prompting an approach more focused on data exchange, between different applications inside companies or even between cooperating businesses.
Businesses are showing interest in using XML as an integral part of their work. Ericsson Microwave Systems (EMW) is a company that sees XML as a conceivable solution to problems in the work with radar communications. An approach towards a solution based on a relational database system has earlier been analysed.
In this project we present an investigation of the work at EMW, and identification and documentation of the problems in the radar communication work. Also, the requirements and expectations that EMW has on XML are presented. Moreover, an analysis has been made to decide to what extent XML could be used to solve the problems of EMW. The analysis was conducted by elucidating the problems and possibilities of XML compared to the previous approach for solving the problems at EMW, which was based on using a relational database management system.
The analysis shows that XML has good features for representing hierarchically structured data, as in the EMW case. It is also shown that XML is good for data integration purposes. Furthermore, the analysis shows that XML, due to its self-describing and weak typing nature, is inappropriate to use in the data semantics and integrity problem context of EMW. However, it also shows that the new XML Schema standard could be used as a complement to the core XML standard, to partially solve the semantics problems.
39
Whitworth, Timothy. "Channel estimation, data detection and training design for wireless communications." Thesis, University of Leeds, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.493283.
Full textAbstract:
With modern wireless communications seeking to attain higher data rates, possibly over time-varying channels, there is an urgent need for fast and efficient techniques for accurate channel estimation and data detection. This thesis proposes a number of novel solutions to the aforementioned problem.
40
Liu, Enfei. "USB dongles for mobile broadband : Data communications for laptop computers." Thesis, KTH, Radio Systems Laboratory (RS Lab), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-169898.
Full textAbstract:
Today a growing number of people need to work on laptops with wireless Internet connection. There are two common wireless Internet access solutions: wireless local area network (WLAN) via hotspot, and high speed wide area cellular network via mobile broadband device such as 3G/4G Universal Serial Bus (USB) dongle. USB dongle was the pioneer product in 3G/4G market, and it is still a popular device in many countries. Mobile broadband can offer both high speed access and mobility. Technically mobile broadband allows Internet connection as long as your mobile transceiver can access your cellular network operator’s network. However, in practice the data rates experienced by a user via mobile broadband are not comparable to the data rates that are available via WLAN. Moreover, mobile broadband has been implemented according to multiple different standards. Hence, in order to provide a user with locally optimal service requires that user must make use of heterogeneous networks. Furthermore, the variety of networks gets increasing due to the emergence of various 4G networks. The aim of this thesis is to explore how heterogeneous networks could be exploited to provide a user of a laptop computer with locally optimal service, while hiding the complexity of this heterogeneous service. The research focuses on the implications of integrating multiple network interfaces into a single USB dongle. Our research shows that multi-mode USB dongle is still needed in market, though there are competitions from smartphones and mobile WiFi devices. We point out that the PPP (Point to Point Protocol) based USB dongle should update to Ethernet USB protocols such as RNDIS (Remote Network Driver Interface Specification) or USB CDC (Communications Device Class) protocols. Furthermore, we suggest a USB dongle should be able to work as a WLAN access point to share Internet with other mobile devices, and it should also work as a WLAN client which can join other hotspots. If hotspot operators can authenticate USB dongles by SIM cards, then users can easily access a great number of hotspots belong to these operators.Mer än någonsin behöver människan arbeta med bärbara datorer med anslutning till trådlöst Internet. Det finns två vanliga trådlösa Internet-anslutningar: trådlöst lokalt nätverk (WLAN på engelska) via en hotspot, eller höghastighets mobilnät via mobilt bredband som 3G/4G Universal Serial Bus (USB) dongel. USB dongeln var pionjär produkten inom 3G/4G marknaden, och den är fortfarande en populär enhet i många länder. Mobilt bredband kan erbjuda både tillgång till höga hastighet och bra mobilitet. Mobilt bredband tillåter, rent tekniskt, användaren hålla en Internet-anslutning så länge mobilen har tillgång till mobilnätets operatörsnät. Men i praktiken är datahastigheterna, som användaren upplever ha via det mobila bredbandet, inte jämförbar med de datahastigheter som är tillgängliga via WLAN. Dessutom har mobilt bredband implementerats enligt flera olika standarder. Således, för att förutse en användare med en optimal lokal tjänst, krävs det att användaren måste använda heterogena nätverk. Dessutom blir olika nätverk allt större på grund av uppkomsten av olika 4G-nät. Syftet med denna avhandling är att undersöka hur heterogena nätverk skulle kunna utnyttjas för att förutse en laptop användare med optimal lokal nätverksservice, samtidigt dölja komplexiteten för användaren om den heterogena tjänsten. Forskningen fokuserar på konsekvenserna av att integrera flera nätverksgränssnitt till en enda USB-dongel. Vår forskning visar att det fortfarande behövs en multi-mode USB dongel på marknaden, dock existerar det konkurrens från smartphones och mobila WiFi-enheter. Vi påpekar även i avhandlingen att PPP (Point-to-Point Protocol) baserade USB dongeln bör uppdateras till Ethernet USB-protokoll, såsom RNDIS (Remote Network Driver Interface Specification) eller USB CDC (Communications Device Class) protokoll. Vidare föreslår vi att en USB-dongel bör kunna fungera som en kopplingspunkt för att dela Internet med andra mobila enheter, och att den också bör fungera som en WLAN-klient som kan ansluta sig till andra hotspots. Om hotspot operatörer kan autentisera USB-donglar genom SIM-kort, så kan användarna enkelt få tillgång till ett stort antal hotspots som tillhör dessa operatörer.
41
Wilson, Martin Paul. "Synthesised local oscillator design considerations for satellite data communications systems." Thesis, University of York, 1992. http://etheses.whiterose.ac.uk/2489/.
Full text
42
Hooke, Adrian J. "Advanced Orbiting Systems: A Standard Architecture for Space Data Communications." International Foundation for Telemetering, 1989. http://hdl.handle.net/10150/614735.
Full textAbstract:
International Telemetering Conference Proceedings / October 30-November 02, 1989 / Town & Country Hotel & Convention Center, San Diego, CaliforniaThe first thirty years of civilian space exploration were characterized by a series of individual missions, focussed towards specific goals and servicing small and close-knit user communities. Spacecraft (constrained by power, weight and volume considerations) were customized towards mission objectives. Their data handling and communications systems were primarily built for simplicity and robustness, and displayed little commonality from mission to mission. All of the easy space missions have now been flown. As we move into the 1990s, requirements exist for complex missions involving Earth observation, exploration and a more permanent human presence in space. Internationalization of these missions is inevitable as a means to distribute and share costs, and to increase their political stability. Automation of their data handling systems is essential to support reliable, low cost operations. Responding to this environment, the Consultative Committee for Space Data Systems (CCSDS) was formed in 1982 to develop and promote a full suite of internationally standardized space data communications protocols. The first set of recommended standards, covering the data handling requirements of conventional free-flying scientific spacecraft, was finalized in 1986. Using the international space station "Freedom" program (a cooperative venture between the US, Europe, Canada and Japan) as a requirements model, the CCSDS has now extended its suite of recommended standards to cover "advanced orbiting systems" such as unmanned and man-tended Earth observation platforms, new space transportation systems, and manned laboratories. These systems, which operate as longterm orbiting facilities and therefore have changing user communities, produce prodigious rates and volumes of data including digitized video and audio. For the first time, the orbiting systems will use local area networks for internal data transfer. On the ground, they will interface with networks designed for worldwide Open Systems Interconnection (OSI). This paper reviews the standard data handling service architecture which has been developed by CCSDS. It describes the communications protocols that are recommended for the networked transfer of space mission data, and focuses on the unique requirements of transmitting many different data types through weak signal, noisy space channels at rates which routinely may reach many hundreds of megabits per second.
43
Deaves, R. H. "The management of communications in decentralised Bayesian data fusion system." Thesis, University of Bristol, 1998. http://hdl.handle.net/1983/ae6cb4d5-96e8-4af4-90c0-fddb4f188369.
Full text
44
Sharakhov, Nikita Igorevich. "Web-Based Data Visualization with 3D Portrayals for Communications Applications." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/50420.
Full textAbstract:
The modern web has evolved into a highly capable software platform, which enables near-native performance, while offering installation-free cross-platform applications with a uniform user base and rapid update deployment. SVG, WebGL, and HTML5 Canvas, along with various higher-level JavaScript frameworks allow web applications to drive both 2D and 3D visualization. These technologies allow developing novel visualization applications, which can be applied in the communication domain to geospatially map service quality, and to provide tools research and education in wireless communication. We present two such web applications GeoSpy and CORNET3D.
GeoSpy provides 2D and 3D visualization of geospatial data on the web. The application is primarily focused on leveraging 3D portrayals to increase the number of broadband Quality of Service (QoS) metrics, which can be attached to a single point on a map. Additionally, GeoSpy has proven to be a flexible visualization platform by giving the user a high level of customization over HTTP API data. This allows GeoSpy to venture beyond broadband mapping, and provide 3D portrayals of any well-formatted geospatial JSON API.
Research of Software Defined Radio (SDR) and Dynamic Spectrum Access (DSA) can be used to significantly improve the wireless QoS. CORNET3D provides a 3D view of the Virginia Tech CORNET SDR testbed with information on which nodes and radios are operational. The application can also display 2D and 3D plots of the spectrum, which is sensed by the radios in real time. The data is sent to the client over a WebSocket connection to enable low latency, compared to conventional HTTP. CORNET3D can teach students about strategies for optimal use of spectrum resources through a game---"by providing them with real-time scoring based on their choices for radio transmission parameters. CORNET3D has demonstrated that the not only can web applications provide rich portrayals of real-time sensor data, but can also serve as a 3D "serious game" platform.Master of Science
45
Sankaran, Mahadevan. "Transparent Asynchronous Transmitter Receiver Interface (TAXI) communications for fiber optic data links." Thesis, This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-01102009-063748/.
Full text
46
Zhang, Peng. "Energy-efficient Clustering Design for M2M Communications." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-143332.
Full textAbstract:
Machine-to-machine (M2M) communications have appeared as an advanced technology for next-generation communications and are undergoing rapid development. In this project, we investigate M2M communications in a wireless cellular network. In M2M communications, clustering is a technology for more efficient data gathering and higher network energy efficiency. We will analyze existing clustering designs in literature and propose two new clustering designs for M2M communications in cellular networks. Performance of the proposed designs will be evaluated thoroughly using both analytical and simulation tools across many aspects, including energy consumption, dead device ratio, residual energy, and network life. The results show that with simple static energy-efficient clustering operations, the network life can be extended by about 50%.
47
Cox, Criston W. "Optimizing bandwidth of tactical communications systems." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2005. http://library.nps.navy.mil/uhtbin/hyperion/05Jun%5FCox.pdf.
Full textAbstract:
Thesis (M.S. in Systems Technology (Joint Command, Control, Communications, Computers and Intelligence (JC4I))--Naval Postgraduate School, June 2005.Thesis Advisor(s): William Kemple, John Osmundson. Includes bibliographical references (p. 59-60). Also available online.
48
Asbery, Christopher W. "SMART GRID COMMUNICATIONS." UKnowledge, 2012. http://uknowledge.uky.edu/ece_etds/10.
Full textAbstract:
Smart grid technologies are starting to be the future of electric power systems. These systems are giving the utilities detailed information about their systems in real time. One of the most challenging things of implementing smart grid applications is employing the communications into the systems. Understanding the available communications can help ease the transition to these smart grid applications. Many of the utility personnel are spending too much time trying to figure out which communication is better for their application or applications. So this thesis presents the different communication types available with discussing the different attributes in which these communication types are going to offer to the utility. Then these communication types are looked such that utilities can quickly understand how to approach the difficult task of obtaining the information from the different smart grid applications by the use of different communication options.
49
Strihagen, Karl. "Evaluation of publish – subscribe protocols for vehicle communications." Thesis, KTH, Skolan för datavetenskap och kommunikation (CSC), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-217524.
Full textAbstract:
Vehicles connected to networks of other vehicles is one promising example of the Internet of Things (IoT). Companies operating fleets of vehicles can benefit from thepossibility to aggregate all of the information that is generated from this network inorder to optimise their logistics and operations. Underlying this network is the need fora communication link that can connect distributed vehicles and efficient protocols tomanage the transmission of information. For vehicles, the cellular network is the best communication infrastructure available.Since cellular usage has a monetary cost that is proportional to data use, this thesisevaluates three protocols (MQTT, MQTT-SN and AMQP) in terms of how much datathey use during typical scenarios with regard to communications patterns and payload.Three different payload sizes were used to simulate different message types, and thepackage loss rate on the communication link was varied from 0% to 30% to bettersimulate real world conditions. The results showed that for small payload sizes the overhead can be the same order ofmagnitude as the payload and MQTT-SN performs significantly better than bothMQTT and AMQP. However, for larger payloads, this effect diminishes. For the largerpayload MQTT-SN actually consumed more data than the other two protocols. Underthe more lossy conditions tested there are some problems running experiments, such asthe underlaying TCP connection breaking in some cases and the time to complete thetask becomes very long. MQTT and AMQP generally performed about the same inmost aspects in the tests, with the exception of how they handle TCPacknowledgements.Fordon som är anslutna till ett nätverk är en lovande applikation av sakernas internt (eng.Internet of Things). För företag vars kärnverksamhet involverar användandet av fordonkan den information som fordonen generar användas till att förbättra verksamheten. Föratt kunna använda nätverket krävs en kommunikationslänk som ansluter fordonet, samtett kommunikationsprotokoll för att förmedla information. För fordon är mobilnätet den bästa tillgängliga kommunikationslänken för att ansluta demtill internet. Att använda mobilnätet kostar pengar i proportion till den datamängd somanvänds, därför behandlas i denna rapport dataåtgången för tre protokoll, AMQP, MQTToch MQTT-SN. För dessa testar vi tre olika storlekar på nyttodata för att göra testerna merverklighetstrogna för typiska användningssituationer, testar vi dessa under inverkan avpaketförluster mellan 0% till 30% på nätverket. Resultaten från testerna visar att för små storlekar på nyttodata är MQTT-SN det protokollsom konsumerar minst data. För större storlekar på nyttodata är dataanvändningen förAMQP och MQTT ungefär likvärdiga i dataanvändning medans MQTT-SN användermer. Vid höga nivåer av paketförluster tog testerna lång tid och det var inte ovanligt attTCP anslutningen bröts. AMQP och MQTT hade överlag ganska lika beteenden, dockmed undantaget hantering av TCP:s leveranskvittens.
50
Mahdavi, Ali Reza. "Data-aided phase control in differential GMSK receivers for narrowband communications." Thesis, University of Hull, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301633.
Full text