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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.
71

Testing of a smart transducer network, based upon open-source technology

Beckius, Mathias January 2016 (has links)
Arduino Verkstad AB, the Swedish branch of Arduino, has developed a prototype that demonstrates a smart transducer network with a self-configurable communication protocol. The protocol is called I2C+, since it is based upon I2C. One of the possible areas of application is the EU funded PELARS project, where Arduino Verkstad is responsible for creating educational tools. Within the PELARS project, a maximum number of transducer modules is expected to be 20 modules, connected at the same time.The aim of this thesis was to create a testing tool and a test suite for the prototype system, which later could be used and also further developed by engineers at Arduino Verkstad, during the development of the final product. Though the testing tool was primarily needed for this particular system, it was considered desirable if it could be reused for similar projects as well.It was relevant to create the testing tool and the test suite in order to analyse the validity of the I2C+ protocol, which might become Arduino's future standard in connectivity between smart transducers. The performance of the I2C+ protocol also affects the implementation of the smart transducer system within the PELARS project.This work has been guided by a specification of requirements and also by a systematic top-down approach of solving several subproblems. A testing tool and a test suite was created, which serves as a proof-of-concept. The testing tool has a modular design, which makes the solution reusable for other purposes. The testing tool and the test suite was validated by using Arduino's prototype as a test object. Although only 10 transducer modules was used during these tests, the results showed that the prototype does not perform well for a growing number of modules. Therefore, improvement of the system and further testing is advised.
72

Design and Implementation of a Constant Envelope OFDM Waveform in a Software-Defined Radio Platform

Ajo Jr, Amos V. 30 June 2016 (has links)
This thesis examines the high peak-to-average-power ratio (PAPR) problem of OFDM and other spectrally-efficient multicarrier modulation schemes, specifically their stringent requirements for highly linear, power-inefficient amplification. The thesis then presents a most intriguing answer to the PAPR-problem in the form of a constant-envelope OFDM (CE-OFDM) waveform, a waveform which employs phase modulation to transform the high-PAPR OFDM signal into a constant envelope signal, like FSK or GMSK, which can be amplified with non-linear power amplifiers at near saturation levels of efficiency. A brief analytical description of CE-OFDM and its suboptimal receiver architecture is provided in order to define and analyze the key parameters of the waveform and their performance impacts. The primary contribution of this thesis is a highly tunable software-defined radio (SDR) implementation of the waveform which enables rapid-prototyping and testing of CE-OFDM systems. The digital baseband processing of the waveform is executed on a general purpose processor (GPP) in the Linux Ubuntu 14.04 operating system, and programmed using the GNU Radio SDR software framework with a mixture of Python and C++ routines. A detailed description of the software implementation is provided, and baseband simulations of the SDR CE-OFDM receiver in additive white Gaussian noise (AWGN) validate the performance of the implemented signal processing. A fully-functional CE-OFDM radio system is proposed in which GPPs executing the software defined transmitter and receiver routines are interfaced with Ettus Universal Software Radio Peripheral (USRP) transceiver front ends. A software testbench is created to enable rapid configuration and testing of the CE-OFDM waveform over all permutations of its parameters, over both simulated and physical RF channels, to draw deeper insights into the characteristics of the waveform and the necessary design considerations and improvements for further development and deployment of CE-OFDM systems. / Master of Science
73

Ionospheric Sounding During a Total Solar Eclipse

Lloyd, William Charles 12 June 2019 (has links)
The ionosphere is a constantly changing medium. From the sun to cosmic rays, the ionosphere proves to be a continually interesting area of study. The most notable change that occurs in the ionosphere is the day and night cycle. The ionosphere is not a singular medium, but rather made up of different sections. The day side of the ionosphere consists of a D, E, F1, and F2 layer. The night day of the ionosphere consists of an E and F layer. These layers all have different properties and characteristics associated with them. A notable interaction is how radio waves propagate through the ionosphere. A radio wave can either reflect, refract, or pass through a layer of the ionosphere depending on the frequency of the signal, among other sources of disturbance. The ability to have a radio wave reflected back downwards is a core principle of an ionosonde, which measures the height of the ionosphere. A solar eclipse presents a night side ionosphere condition during the day. The change in the ionosphere that the eclipse will cause is something not a lot of research has gone into. This thesis aims to elaborate on the design and development of an ionosonde along with eventual ionosphere readings during the August 2017 total solar eclipse. / Master of Science / The atmosphere that surrounds the earth is made up of various unique regions. The region of interest for this thesis is the ionosphere. The ionosphere plays an important role in wireless communication of radio waves. It follows that changes in the ionosphere are something of great interest and study. A notable change that the ionosphere undergoes on a daily basis is the shift from the day side to the night side. A solar eclipse serves not only as a spectacular sight, but also to bring a night side condition to the day side. This thesis aims to uncover the changes that will occur to the ionosphere during the August 2017 total solar eclipse.
74

A Zynq-based Cluster Cognitive Radio

Rooks, Kurtis M. 25 July 2014 (has links)
Traditional hardware radios provide very rigid solutions to radio problems. Intelligent software defined radios, also known as cognitive radios, provide flexibility and agility compared to hardware radio systems. Cognitive radios are well suited for radio applications in a changing radio frequency environment, such as dynamic spectrum access. In this thesis, a cognitive radio is demonstrated where the system self reconfigures to demodulate a detected waveform. The GNU Radio framework is used to provide basic software defined radio building blocks and is supplemented with FPGA accelerators. The use of GNU Radio compliant hardware interfaces allows for seamless hardware/software radio deployments. Dynamic resource mapping allows radio designers to operate at a layer of abstraction above the physical radio implementation. By establishing lower level abstraction layers, future researchers can focus on larger picture concepts such as learning algorithms and behavioral models for the cognitive engine. / Master of Science
75

Making Radios with GReasy: GNU Radio With FPGAs Made Easy

Marlow, Ryan Lane 29 August 2014 (has links)
Radio technology is rapidly evolving and as processing capabilities and algorithms become more complex, the need for alternative compilation and user interface abstraction increases. Field Programmable Gate Array (FPGA) technology introduces unique reconfigurable hardware architectures that can aid in software defined radio (SDR) design. FPGAs have greater processing capability than traditional general purpose processors (GPP) found in desktop workstations. This work builds on an ongoing project, GReasy, that augments a Linux based open source SDR development platform, GNU Radio, with FPGA processing capabilities. By delegating processing intensive portions of a radio design to the Xilinx Zynq FPGA architecture, the domain of deployable radios by GNU Radio can be broadened. Xilinx Zynq, integrates the FPGA fabric and CPU onto a single chip, which eliminates the need for a controlling host computer; thus, providing a single, portable, low-power, embedded platform. This thesis presents a Zynq capable version of GNU Radio -- an open-source rapid radio deployment tool -- with an enhanced flow that utilizes the processing capability of FPGAs. This work features TFlow -- an FPGA back-end compilation accelerator for instant FPGA assembly. GReasy generates a description of the hardware components that are used by TFlow for the instant FPGA assembly. Once the FPGA is programmed with a design based on the description generated by GReasy, modules and the target hardware can be parameterized to realize an even larger class of applications and further solidify the concept of rapid assembly of software defined radios. / Master of Science
76

The evolution of the black wildebeest, Connochaetes gnou, and modern largemammal faunas in central Southern Africa

Brink, James Simpson 12 1900 (has links)
Thesis (PhD (Archaeology))--University of Stellenbosch, 2005. / This study investigates the evolution of modern mammalian faunas in the central interior of southern Africa by testing the hypothesis that the evolution of the black wildebeest, Connochaetes gnou, was directly associated with the emergence of Highveld-type open grasslands in the central interior. Southern Africa can be distinguished from other arid and semi-arid parts of the continent by the presence of an alliance of endemic grazing ungulates. The black wildebeest is characteristic of this alliance. Open habitats are essential for the reproductive behaviour of the black wildebeest, because territorial males require an unobstructed view of their territories in order to breed. The specialised territorial breeding behaviour of the black wildebeest is the reason why the black wildebeest is historically confined to the Highveld and Karoo areas and why it is reproductively isolated from sympatric blue wildebeest, Connochaetes taurinus. The finds from a number of fossil-rich localities, dating from the recent past to approximately a million years ago, have been identified. The remains referred to ancestral C. gnou have been subjected to detailed qualitative and quantitative osteological comparisons with cranial and post-cranial elements of modern and fossil reference specimens. This material includes extant southern African alcelaphines and fossil materials of C. gnou, the extinct giant wildebeest, Megalotragus priscus, and North African fossil alcelaphines. The results show that cranial changes in fossil C. gnou, particularly the more forward positioning of the horns, basal inflation of the horns and the resultant re-organisation of the posterior part of the skull, preceded other skeletal modifications. These cranial changes indicate a shift towards more specialised territorial breeding behaviour in the earliest ancestral black wildebeest, evident in the specimens of the c. million year old Free State site of Cornelia-Uitzoek. Since the territorial breeding behaviour of the black wildebeest can only function in open habitat and since cranial characters associated with its territorial breeding behaviour preceded other morphological changes, it is deduced that there was a close association between the speciation of C. gnou from a C. taurinus-like ancestor and the appearance of permanently open Highveld-type grasslands in the central interior of southern Africa. This deduction is supported by the lack of trophic distinction between the modern black and blue wildebeest, suggesting that the evolution of the black wildebeest was not accompanied by an ecological shift. It is concluded that the evolution of a distinct southern endemic wildebeest in the Pleistocene was associated with, and possibly driven by, a shift towards a more specialised kind of territorial breeding behaviour, which can only funtion in open habitat. There are significant post-speciation changes in body size and limb proportions of fossil C. gnou through time. The tempo of change has not been constant and populations in the central interior underwent marked reduction in body size in the last 5000 years. Vicariance in fossil C. gnou is evident in different rates of change that are recorded in the populations of generally smaller body size that became isolated in the Cape Ecozone. These daughter populations, the result of dispersals from the central interior, became extinct at the end of the Pleistocene.
77

Sistemas de informática e informação da atenção básica do Sistema Único de Saúde e o software livre: possibilidades e perspectivas / The Brazilian Unified National Health System (SUS) Primary Health, its informatics and information systems and the free software: perspectives and possibilities

Cortizo, Carlos Tato 06 December 2007 (has links)
Introdução: A Atenção Básica do Sistema Único de Saúde SUS é definida pelo Ministério da Saúde como um conjunto de ações e serviços de saúde no âmbito individual e coletivo, desenvolvidos com práticas gerenciais, sanitárias e sociais participativas, através de ações complexas nos cuidados e atenção à saúde da população do seu território e fundamentada nos princípios da universalidade, integralidade e da eqüidade. Os sistemas de informática em saúde da atenção básica são tecnologias estratégicas na gestão e governança sobre a situação de saúde da população em cada nível de responsabilidade sanitária. O cerne de funcionamento dos sistemas de informática é o software. A literatura pesquisada relata que os softwares dos sistemas de informática em saúde apresentam vários aspectos: inflexibilidade para mudanças, altos custos, baixa eficácia, são frágeis em relação à segurança e a privacidade, não adotam padrões tecnológicos e de saúde, apresentam dificuldades na escalabilidade, são refratários a adaptações às culturas e línguas locais e induzem ao aprisionamento tecnológico dos sistemas de informação em saúde. Neste contexto, o objetivo deste estudo foi o de identificar e analisar quais são as contribuições e limitações do software livre para os sistemas de informática e informação na atenção básica do SUS. Metodologia: Estudo de caso exploratório e qualitativo, comparando dois municípios que utilizam software livre e software privativo nos sistemas de atenção básica do SUS, a partir de critérios obtidos na literatura pesquisada. Resultados: A utilização de software livre nos sistemas de atenção básica do SUS de Campinas e São Paulo apresentou limites nos seguintes tópicos, utilizados como critérios de análise: educação, segurança, privacidade e padrões abertos. A utilização do software livre demonstrou vantagens para os municípios estudados nos seguintes tópicos: custos, escalabilidade, autonomia tecnológica, adaptação do software ao idioma e à cultura local, estabilidade e impacto na qualidade dos serviços de saúde. Conclusão: O software livre é uma alternativa tecnológica viável, robusta e flexível e oferece novas perspectivas para a construção de sistemas de informática e informação da Atenção Básica em saúde / The Primary Health Care of the Brazilian Unified National Health System (SUS) is defined by the Health Ministry as a set of actions and services in the individual and collective scopes developed through managerial sanitary and social participative practices by means of complex actions in the attention and care of thee health of the population within their territory based on the principles of universality, integrality and equity . The health informatics system of the basic attention are strategic tools of management and managery of the health status of the population at each level of sanitary responsibility. The core of operation of the informatics system is the software .The researched literature reports the health and informatics system software to present inflexibility for change, high cost and low efficacy, fragility concerning privacy and safety, lack of technological and health patterns and difficulties in scalability . The software is also depicted as being refractory to local languages and cultures, and to induce technological trap of the health informatics systems. Within this context the aim of the study was the identification and analysis of the contributions and limitations of free software for the informatics and information systems of the primary health of SUS. METODOLOGY: Exploratory qualitative study comparing two municipalities making use of free software and private software in their SUS primary health system based on the criteria obtained from the literary review. RESULTS: The use of free software in the basic attention of the SUS of Campinas and São Paulo presents limitations in the following topics used as analysis criteria: education, safety, privacy and open patterns. The use of free software proved advantageous for the surveyed municipalities in the following topics: costs, scalability, technologic autonomy, stability, adaptation of the software to the local language and culture and impact on the quality of health services. CONCLUSION: Free software is a viable, robust and flexible technological alternative that offers new perspectives for th construction of information and informatics systems of the primary health care.
78

Separação cega de fontes aplicada no sensoriamento do espectro em rádio cognitivo / Blind source separation applied in spectrum sensing in cognitive radio

Rocha, Gustavo Nozella 01 June 2012 (has links)
Cognitive radio technology has been an important area of research in telecommunications for solving the problem of spectrum scarcity. That\'s because in addition to allowing dynamic allocation of the electromagnetic spectrum, cognitive radios must be able to identify the non cognitive user\'s transmission on the channel. This operation is only possible through the continuous sensing of the electromagnetic spectrum. In this context, this paper presents a detailed study on spectrum sensing, an important stage in cognitive radio technology. For the presentation of this work, a detailed study on software dened radio (SDR) was carried out, without which it would be impossible to work with cognitive radios, once they are implemented by means of SDR technology. It was also presented the tools GNU Radio and USRP, which together form a solution of SDR, through implementation of AM receivers. The theoretical foundations of spectrum sensing and blind source separation (BSS) are presented and then is made a detailed study of the use of BSS for spectral sensing. From the study of BSS, it is possible to use new metrics for decision making about the presence or the absence of a primary user in the channel. Throughout the study, simulations and implementations were conducted on MATLAB in order to perform various situations, and, nally, it is presented outcomes and conclusions reached during the work. / A tecnologia de rádio cognitivo tem sido uma importante área de pesquisa em telecomunicações para a solução do problema da escassez espectral. Isto porque, além de permitirem a alocação dinâmica do espectro eletromagnético, os rádios cognitivos devem ser capazes de identificar as transmissões de usuários não cognitivos no canal. Esta operação só é possível por meio do sensoriamento contínuo do espectro eletromagnético. Neste contexto, este trabalho apresenta um estudo detalhado sobre o sensoriamento de espectro, uma importante etapa da tecnologia de rádios cognitivos. Para a apresentação deste trabalho foi realizado um estudo detalhado a respeito de rádio definido por software (SDR), sem o qual não seria possível o trabalho com rádios cognitivos, uma vez que este é implementado por meio da tecnologia de SDR. Também foram apresentadas as ferramentas GNU Radio e USRP, que, juntas, formam uma solução de SDR, por meio de implementações de receptores AM. Os fundamentos teóricos de sensoriamento de espectro e separação cega de fontes (BSS) são apresentados e, em seguida, é realizado um estudo aprofundado do uso de BSS para o sensoriamento espectral. A partir do estudo de BSS, é possível utilizar novas métricas de decisão a respeito da presença ou não de um usuário primário no canal. Durante todo este trabalho foram realizadas implementações e simulações no MATLAB com a finalidade de executar diversas situações e, finalmente, são apresentados resultados verificados e conclusões obtidas neste trabalho. / Mestre em Ciências
79

Sistemas de informática e informação da atenção básica do Sistema Único de Saúde e o software livre: possibilidades e perspectivas / The Brazilian Unified National Health System (SUS) Primary Health, its informatics and information systems and the free software: perspectives and possibilities

Carlos Tato Cortizo 06 December 2007 (has links)
Introdução: A Atenção Básica do Sistema Único de Saúde SUS é definida pelo Ministério da Saúde como um conjunto de ações e serviços de saúde no âmbito individual e coletivo, desenvolvidos com práticas gerenciais, sanitárias e sociais participativas, através de ações complexas nos cuidados e atenção à saúde da população do seu território e fundamentada nos princípios da universalidade, integralidade e da eqüidade. Os sistemas de informática em saúde da atenção básica são tecnologias estratégicas na gestão e governança sobre a situação de saúde da população em cada nível de responsabilidade sanitária. O cerne de funcionamento dos sistemas de informática é o software. A literatura pesquisada relata que os softwares dos sistemas de informática em saúde apresentam vários aspectos: inflexibilidade para mudanças, altos custos, baixa eficácia, são frágeis em relação à segurança e a privacidade, não adotam padrões tecnológicos e de saúde, apresentam dificuldades na escalabilidade, são refratários a adaptações às culturas e línguas locais e induzem ao aprisionamento tecnológico dos sistemas de informação em saúde. Neste contexto, o objetivo deste estudo foi o de identificar e analisar quais são as contribuições e limitações do software livre para os sistemas de informática e informação na atenção básica do SUS. Metodologia: Estudo de caso exploratório e qualitativo, comparando dois municípios que utilizam software livre e software privativo nos sistemas de atenção básica do SUS, a partir de critérios obtidos na literatura pesquisada. Resultados: A utilização de software livre nos sistemas de atenção básica do SUS de Campinas e São Paulo apresentou limites nos seguintes tópicos, utilizados como critérios de análise: educação, segurança, privacidade e padrões abertos. A utilização do software livre demonstrou vantagens para os municípios estudados nos seguintes tópicos: custos, escalabilidade, autonomia tecnológica, adaptação do software ao idioma e à cultura local, estabilidade e impacto na qualidade dos serviços de saúde. Conclusão: O software livre é uma alternativa tecnológica viável, robusta e flexível e oferece novas perspectivas para a construção de sistemas de informática e informação da Atenção Básica em saúde / The Primary Health Care of the Brazilian Unified National Health System (SUS) is defined by the Health Ministry as a set of actions and services in the individual and collective scopes developed through managerial sanitary and social participative practices by means of complex actions in the attention and care of thee health of the population within their territory based on the principles of universality, integrality and equity . The health informatics system of the basic attention are strategic tools of management and managery of the health status of the population at each level of sanitary responsibility. The core of operation of the informatics system is the software .The researched literature reports the health and informatics system software to present inflexibility for change, high cost and low efficacy, fragility concerning privacy and safety, lack of technological and health patterns and difficulties in scalability . The software is also depicted as being refractory to local languages and cultures, and to induce technological trap of the health informatics systems. Within this context the aim of the study was the identification and analysis of the contributions and limitations of free software for the informatics and information systems of the primary health of SUS. METODOLOGY: Exploratory qualitative study comparing two municipalities making use of free software and private software in their SUS primary health system based on the criteria obtained from the literary review. RESULTS: The use of free software in the basic attention of the SUS of Campinas and São Paulo presents limitations in the following topics used as analysis criteria: education, safety, privacy and open patterns. The use of free software proved advantageous for the surveyed municipalities in the following topics: costs, scalability, technologic autonomy, stability, adaptation of the software to the local language and culture and impact on the quality of health services. CONCLUSION: Free software is a viable, robust and flexible technological alternative that offers new perspectives for th construction of information and informatics systems of the primary health care.
80

Quality assessment of cryopreserved spermatozoa of the blesbok (Damaliscus pygargus phillipsi), blue wildebeest (Connochaetes taurinus) and African buffalo (Syncerus caffer)

Mynhardt, Neil Philip 22 August 2012 (has links)
M.Sc. / Climate change, loss of habitat and over-exploitation of natural resources as well as the introduction of invasive alien species through human activities are resulting in an ever increasing risk of extinction of many plant and animal species. There are two major approaches to conserving threatened and endangered species. Firstly the large scale preservation of natural habitat and ecological processes, thereby protecting the species inhabiting the habitat. The second approach involves the ex-situ breeding of rare and endangered species. It is estimated that in the next 200 years approximately 800 mammalian species will require the assistance of breeding programs to ensure long term genetic viability. Biological Resource Banks (BRB) can potentially contribute to this challenge by providing a source of genes that can be used to counter the effects of external selection pressures, genetic drift and inbreeding depression in small or fragmented populations. These banks commonly contain biological materials such as cryopreserved sperm, embryos and cell cultures mainly as genetic and research resources. . Biological resource banks can potentially use these cryopreserved gametes together with assisted reproductive technologies (ART), such as artificial insemination (AI), in vitro fertilisation (IVF), embryo transfer (ET), intracytoplasmic sperm injection (ICSI) and nuclear transfer (NT) to maintain genetic heterogeneity in ex-situ and wild populations. Ascertaining the appropriate protocols for developing the ARTs necessary for non-domestic species is one of the major challenges faced by reproductive physiologists. Typically, there is very little available information about the processing of semen, the effects of diluents, concentration and type of cryoprotectants and freeze-thaw methods for sperm samples of non-domestic species. Procedures proven to be highly effective in humans and laboratory or domestic species, are frequently adopted and modified for use in related wildlife species. It is thus necessary to gain knowledge of the reproductive physiology of wildlife species in order to define effective protocols for the cryopreservation of biomaterials which assists in the conservation of South Africa‘s diverse wildlife species. Sperm quality assessment is a useful tool for assessing the reproductive health of free-ranging populations as well as for selecting individuals for future assisted reproduction programs.

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