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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.
1

RADAR BACKSCATTER MEASUREMENT ACCURACY FOR SPACEBORNE SCANNING PENCIL-BEAM SCATTEROMETERS

Long, David G. 11 1900 (has links)
International Telemetering Conference Proceedings / October 30-November 02, 1995 / Riviera Hotel, Las Vegas, Nevada / A radar scatterometer transmits a series of RF pulses and measures the total-power (energy) of the backscattered signal. Measurements of the backscattered energy from the ocean's surface can be used to infer the near-surface wind vector [7]. Accurate backscatter energy measurements are required to insure accurate wind estimates. Unfortunately, the signal measurement is noisy so a separate measurement of the noise-only total-power is subtracted from the signal measurement to estimate the echo signal energy. A common metric for evaluating the accuracy of the scatterometer energy measurement is the normalized signal variance, termed K(p). In designing a scatterometer tradeoffs in design parameters are made to minimize K(p). Spaceborne scatterometers have traditionally been based on fan-beam antennas and CW modulation for which expressions for K(p) exist. Advanced pencil-beam scatterometers, such as SeaWinds currently being developed by NASA use modulated Signals so that new K(p) expressions are required. This paper outlines the derivation of the generalized K(p) expression. While very complicated in its exact form, with a simplified geometry the K(p) expression can be related to the radar ambiguity function. The resulting analysis yields insights into the tradeoffs inherent in a scatterometer design and permits analytic tradeoffs in system performance.
2

Aplicações da informação genômica no estudo de populações selecionadas /

Maiorano, Amanda Marchi. January 2019 (has links)
Orientador: Josineudson Augusto II de Vasconcelos Silva / Coorientador: Daniela Andressa Lino Lourenço / Coorientador: Joslaine Noely dos Santos Gonçalves Cyrillo / Banca: Danísio Prado Munari / Banca: Nedênia Bonvino Stafuzza / Banca: Rusbel Raul Aspilcueta Borquis / Resumo: A disponibilidade de painéis de polimorfismos de nucleotídeos únicos (SNPs) a baixo custo tem viabilizado estudos genômicos em espécies de interesse econômico. Os objetivos do presente estudo foram conduzir análises de estruturação da população e assinaturas de seleção em duas populações de bovinos Gir selecionadas para diferentes critérios de seleção (corte ou leite); e investigar se a estimativa do efeito materno para característica medida na progênie apresenta maior acurácia com uso de "pool" de sêmen e informação genômica em diferentes cenários simulados de suínos. Análise de componentes principais (PCA) e Análise Discriminante de Componentes Principais (DAPC) foram utilizadas para verificar a estrutura da população nas populações Gir analisadas, e três métodos diferentes foram utilizados na detecção de assinaturas de seleção: índice de fixação (Fst), Escore de Integração dos Haplótipos (iHS) e Homozigose do Haplótipo Estendido Entre Populações (XP-EHH). Diferenciação genética entre as duas populações de bovinos foi observada nos resultados de PCA e DAPC. Um total de 282 genes foram identificados sob seleção, com base nos testes Fst, iHS e XP-EHH, dos quais 35 genes estão associados com QTL previamente descritos em bovinos. Os padrões de variação genética nos bovinos Gir foram consistentes com a presença de pressões seletivas em algum momento na história das populações de corte e leite. Estes resultados fornecem informações complementares sobre regiões genômicas de intere... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The availability of commercial SNP panels at a low cost has made it possible the application of genomic studies in domestic species. The aim of this study was to conduct population structure and signatures of selection analyzes in two populations of Gir cattle selected for different criteria (beef or dairy); and to investigate whether maternal direct effect for litter birth weight can be improved when pooled semen and genomic information are used in different simulated scenarios in pigs. Principal Component Analysis (PCA) and Discriminant Analysis of Principal Components (DAPC) were used to verify population structure in the studied Gir cattle populations, and three different methods were used to detect signatures of selection: fixation index (Fst), Integrated Haplotype Score (iHS), and Cross-Population Extend Haplotype Homozygosity (XP-EHH). Genetic differentiation between the two cattle populations was observed in the PCA and DAPC results. A total of 282 genes were identified under selection based on the Fst, iHS and XP-EHH tests, of which 35 genes are associated with QTL previously described in cattle. The patterns of genotypic variation in Gir cattle were consistent with the presence of selective pressures at some point in the history of the beef and dairy populations. These findings can provide complementary information on genomic regions of interest for functional genomic studies, genome-wide associations, and the implementation of breeding schemes aiming genetic improv... (Complete abstract click electronic access below) / Doutor
3

Measurement Accuracy Evaluation for Passive Radar Systems

Alslaimy, Moayad A. January 2020 (has links)
No description available.
4

NEW TUNER CHARACTERIZATION AND GAIN COMPENSATION TECHNIQUES FOR ON-WAFER MICROWAVE NOISE MEASUREMENT

Yang, Benson 04 1900 (has links)
<p>Accurate characterization of a noisy device starts with an accurate measurement system. Measurement uncertainty and error continues to be a challenging subject as technology advances. The conventional method to noise characterization of on-wafer devices is to determine its noise parameters. To extract the noise parameters of an unpackaged device involves a sophisticated measurement system and calibration procedure. This thesis presents a new automated on-wafer noise measurement system based on Labview 8.5.1 which is used to examine measurement uncertainty for noise parameter extraction. The software program can be used and customized for a wide range of on-wafer noise measurements. This thesis covers the design and operation of the measurement system, which is then used to analyze measurement uncertainty.</p> <p>Measurement uncertainty can be due to various sources from environmental surroundings to instrument settings and the components of the system itself. In many scenarios, inaccuracies are random and cannot be completely resolved. In this thesis, a new tuner characterization technique that improves source tuner characterization is presented. Additionally, a new gain compensation technique is applied to measured noise powers that attempt to improve noise parameter extraction accuracy is proposed. The tuner characterization technique is evaluated against a current industry solution and the affects of the gain compensation technique is evaluated using a newly developed figure of merit. This research work concludes that a direct noise power correction is valid and necessary to further improve noise parameter accuracy. However, the proposed technique when applied resulted in minimal change to the overall noise parameter data. It is found that that source termination selection and total points used for fitting continue to be the major source of uncertainty for noise parameter accuracy.</p> / Master of Applied Science (MASc)
5

An investigation of the measurement accuracy and productivity of a Waratah HTH 625c Processor Head

Saathof, David January 2014 (has links)
Log processor heads have become increasingly used in New Zealand (NZ) forest harvesting operations to increase productivity and improve worker safety. Information regarding the measurement accuracy and productivity of new model processor heads is limited. As a result, log quality control (QC) is carried out on logs that have been merchandised by a processor head. This task can have a high risk for injury from man – machine interaction. A trend between studies was that older model Waratah’s did not have sufficient measurement accuracy to alleviate the requirement for log QC. In this study, a Waratah HTH 625c processor head operating in NZ was analysed for measurement accuracy and productivity. Measurement accuracy was considered by measuring logs for length, diameter and branch size. A comparison of two methods of processing was also considered to determine measurement accuracy, productivity and production efficiency for the way logs are delimbed and merchandised. Once gathered, the data was then analysed to identify significant effects, trends and relationships between variables. Length measurements were highly accurate but diameter measurements were under- estimated. It was also evident that although there was absolute accuracy, there was a high variability in measurements with underestimating and overestimating. Branch size was also found to have a significant impact in reducing length measurement accuracy and productivity. Single pass processing has significantly higher production efficiency than two pass processing, although single pass processing had a higher length error associated with it. The Waratah HTH 625c processor head has better measurement accuracy than older model Waratah’s. However, logs are still cut out-of-spec which will require a log QC to identify. As measurement technology is further improved in processor heads, and improvements to NZ’s plantation resource (improved form and smaller branching) are realised at harvest age, measurement accuracy and productivity of log processor heads will further improve.
6

On the Quality of Computer Network Measurements / Om kvaliteten på datornätverks mätningar

Arlos, Patrik January 2005 (has links)
Due to the complex diversity of contemporary Internet-services, computer network measurements have gained considerable interest during recent years. Since they supply network research, development and operations with data important for network traffic modelling, performance and trend analysis, etc. The quality of these measurements affect the results of these activities and thus the perception of the network and its services. This thesis contains a systematic investigation of computer network measurements and a comprehensive overview of factors influencing the quality of performance parameters obtained from computer network measurements. This is done using a novel network performance framework consisting of four modules: Generation, Measurement, Analysis and Visualization. These modules cover all major aspects controlling the quality of computer network measurements and thus the validity of all kinds of conclusions based on them. One major source of error is the timestamp accuracy obtained from measurement hardware and software. Therefore, a method is presented that estimates the timestamp accuracy obtained from measurement hardware and software. The method has been used to evaluate the timestamp accuracy of some commonly used hardware (Agilent J6800/J6830A and Endace DAG 3.5E) and software (Packet Capture Library). Furthermore, the influence of analysis on the quality of performance parameters is discussed. An example demonstrates how the quality of a performance metric (bitrate) is affected by different measurement tools and analysis methods. The thesis also contains performance evaluations of traffic generators, how accurately application-level measurements describe network behaviour, and of the quality of performance parameters obtained from PING and J-OWAMP. The major conclusion is that measurement systems and tools must be calibrated, verified and validated for the task of interest before using them for computer network measurements. A guideline is presented on how to obtain performance parameters at a desired quality level. / Datornät används i mer och mer i vårt dagliga liv, de används för att telefonera, läsa tidningar, se på TV, handla, boka resor etc. På grund av denna diversiteten bland tjänsterna så har mätningar blivit populära under senare år. Detta då de förser nätverksforskningen, utvecklingen och driften med data som används för trafik modellering, prestanda och trend analys. Kvaliteten på dessa mätningar kommer därför direkt påverka resultaten av dessa aktiviteter och därför vår uppfattning av nätverket och dess tjänster. I denna avhandling ger vi en systematisk översikt av datornätverks mätningar och en omfattande översikt av de faktorer som påverkar kvaliteten av prestanda parametrar som tas fram via mätningar. Detta görs genom ett nytt ramverks som beskriver de fyra moduler som påverkar mätningarnas kvalitet: generering, mätning, analys och visualisering. En av de stora källorna till kvalitets problem är noggrannheten på tidstämplar. Dessa tidstämplar beskriver när händelser skedde i nätverket. På grund av detta så presenterar vi en metod som kan uppskatta den tidstämpling noggrannhet som man kan få från mätverktyg, både hård och mjukvara. Metoden används för att utvärdera noggrannheten på några vanliga verktyg, två hårdvarubaserade system (Agilent J6800/J6830A och Endace DAG 3.5E) samt mjukvarubaserade system (Packet Capture Library). Vidare så diskuteras påverkan som analysen har på kvaliteten, och ett exempel ges på hur ett prestanda mått (bitrate) påverkas av mätsystem (hård/mjukvara) och analys metod. Avhandlingen innehåller dessutom utvärderingar av trafik generatorer, applikations mätningar och kvaliteten på mättningar gjorda med PING och J-OWAMP. Huvudslutsatsen i arbetet är att mätsystem och verktyg måste kalibreras, verifieras och valideras innan de används. Baserat på detta så presenterar vi en riktlinje över hur man gör detta.
7

Acurácia de diferentes indicadores eletrocardiográficos na detecção de hipertrofia ventricular esquerda em pacientes hipertensos

Gonçalves, Renato de Souza [UNESP] 10 May 2013 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:32:12Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-05-10Bitstream added on 2014-06-13T19:02:36Z : No. of bitstreams: 1 goncalves_rs_dr_botfm.pdf: 1301205 bytes, checksum: e3b3c0f2b675654eacec3e3870a2e77c (MD5) / A utilização de índices eletrocardiográficos que associam a duração do QRS e do tempo de ativação ventricular melhorou a sensibilidade do exame no diagnóstico de hipertrofia ventricular esquerda, sobretudo em pacientes com doença arterial coronariana. Em pacientes com hipertensão arterial sistêmica as informações são escassas. Os objetivos deste estudo foram: avaliar a acurácia de critério que usa a duração do QRS e o tempo de ativação ventricular para detectar hipertrofia ventricular esquerda; comparar essa acurácia com critérios utilizados na prática médica; verificar quais variáveis clínicas se associam com modificações da acurácia do eletrocardiograma. O estudo foi retrospectivo, incluindo pacientes hipertensos assintomáticos, cadastrados de forma consecutiva nos ambulatórios de atendimento primário de hipertensão arterial do Hospital das Clínicas da Faculdade de Medicina de Botucatu, que realizaram eletrocardiograma e ecocardiograma no mesmo dia, no período entre 2004 e 2006 para detecção de hipertrofia ventricular esquerda. Foram excluídos: portadores de valvopatia, cardiopatia congênita, infarto do miocárdio e insuficiência cardíaca, os que apresentassem no eletrocardiograma bloqueio do ramo direito, bloqueio do ramo esquerdo, fibrilação atrial, pré-excitação ventricular, ritmo de marcapasso e áreas eletricamente inativas, pacientes com fração de ejeção menor que 0,50 no ecocardiograma. Os critérios eletrocardiográficos foram: Sokolow-Lyon, Cornell, Framingham, Cornell-strain, critério de massa pelo eletrocardiograma indexada a superfície corpórea (ImECG), escore de Romhilt-Estes e de Perugia. O eletrocardiograma foi analisado por médico experiente que não conhecia o resultado do ecocardiograma. A massa ventricular esquerda indexada pela superfície corpórea, detectada ao ecocardiograma... / not available
8

Acurácia de diferentes indicadores eletrocardiográficos na detecção de hipertrofia ventricular esquerda em pacientes hipertensos /

Gonçalves, Renato de Souza. January 2013 (has links)
Orientador: Beatriz Bojikian Matsubara / Coorientador: Luis Cuadrado Martin / Banca: João CArlos Hueb / Banca: Roberto Jorge da Silva Franco / Banca: Fábio Villaça Guimarães Filho / Banca: Alexandre Rodrigues / Resumo: A utilização de índices eletrocardiográficos que associam a duração do QRS e do tempo de ativação ventricular melhorou a sensibilidade do exame no diagnóstico de hipertrofia ventricular esquerda, sobretudo em pacientes com doença arterial coronariana. Em pacientes com hipertensão arterial sistêmica as informações são escassas. Os objetivos deste estudo foram: avaliar a acurácia de critério que usa a duração do QRS e o tempo de ativação ventricular para detectar hipertrofia ventricular esquerda; comparar essa acurácia com critérios utilizados na prática médica; verificar quais variáveis clínicas se associam com modificações da acurácia do eletrocardiograma. O estudo foi retrospectivo, incluindo pacientes hipertensos assintomáticos, cadastrados de forma consecutiva nos ambulatórios de atendimento primário de hipertensão arterial do Hospital das Clínicas da Faculdade de Medicina de Botucatu, que realizaram eletrocardiograma e ecocardiograma no mesmo dia, no período entre 2004 e 2006 para detecção de hipertrofia ventricular esquerda. Foram excluídos: portadores de valvopatia, cardiopatia congênita, infarto do miocárdio e insuficiência cardíaca, os que apresentassem no eletrocardiograma bloqueio do ramo direito, bloqueio do ramo esquerdo, fibrilação atrial, pré-excitação ventricular, ritmo de marcapasso e áreas eletricamente inativas, pacientes com fração de ejeção menor que 0,50 no ecocardiograma. Os critérios eletrocardiográficos foram: Sokolow-Lyon, Cornell, Framingham, Cornell-strain, critério de massa pelo eletrocardiograma indexada a superfície corpórea (ImECG), escore de Romhilt-Estes e de Perugia. O eletrocardiograma foi analisado por médico experiente que não conhecia o resultado do ecocardiograma. A massa ventricular esquerda indexada pela superfície corpórea, detectada ao ecocardiograma... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: not available / Doutor
9

Mensuração da alteração dimensional de uma silicona por condensação através de três métodos distintos / The dimensional change measurement of a silicone condensation trhough three different methods

Cunha, Thaiana Damaceno 27 April 2015 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2015-12-04T14:43:43Z No. of bitstreams: 1 thaianadamacenocunha.pdf: 1265962 bytes, checksum: 6d8fb90304d78d671faf48a4a00e64e5 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2015-12-07T03:22:42Z (GMT) No. of bitstreams: 1 thaianadamacenocunha.pdf: 1265962 bytes, checksum: 6d8fb90304d78d671faf48a4a00e64e5 (MD5) / Made available in DSpace on 2015-12-07T03:22:42Z (GMT). No. of bitstreams: 1 thaianadamacenocunha.pdf: 1265962 bytes, checksum: 6d8fb90304d78d671faf48a4a00e64e5 (MD5) Previous issue date: 2015-04-27 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O objetivo deste estudo foi mensurar a alteração dimensional de uma silicona por condensação através de um paquímetro digital (Mitutuyo), de um estéreo microscópio (Olympus) e de uma máquina de medição tridimensional por coordenadas (Mitutuyo). Foram realizadas 4 moldagens através de um dispositivo específico com a silicona por condensação pesada e leve Speedex (Coltene/Vigodent). Em cada um dos 4 moldes 4 distâncias foram mensuradas pelos 3 instrumentos, em 4 tempos distintos: no momento da remoção do molde e após 30min, 1h e 7 dias. As médias das mensurações foram submetidas ao teste estatístico Kruskal-Wallis com nível de significância de 5%. Os resultados mostraram diferenças significantes entre as alterações dimensionais verificadas por cada um dos instrumentos de medição, as mensurações realizadas pelo paquímetro digital e pela máquina de medição tridimensional por coordenadas apresentaram alterações dimensionais significantes nos 4 tempos testados, enquanto as pelo estéreo microscópio não apresentaram diferença significante nos 4 tempos. Concluiu-se que as alterações dimensionais verificadas nos moldes da silicona por condensação testada obtidas através de cada instrumento de medição utilizado nesta pesquisa foram diferentes entre si, evidenciando que os diferentes métodos de medição utilizados podem fornecer resultados distintos, e consequentemente, indicações equivocadas. / The aim of this study was to measure the dimensional changes of a silicone condensation using a digital paquimeter (Mitutuyo), an estereomicroscope (Olympus) and a three-dimensional coordinate measuring machine (Mitutuyo). Were made 4 impressions trhough a specif device using the putty and light silicone condensation Speedex (Coltene/Vigodent). Four distances were measured at each impression through the 3 instruments at 4 different times: in the moment of removal of the die and after 30min, 1h e 7 days. The avarage of the measurements were subimitted to the statistical test Kruskal-Wallis with level of significance of 5%. The results shows significant diferences between the dimensional changes verified by each one of the measuring instruments, the measurements through the digital paquimeter and the measurements trhough the three-dimensional coordinate measuring machine showed significant dimensional changes in the 4 tested times, while the measurements through the estereomicroscope did not show significant difference in the 4 tested times. It concludes that the dimensional changes verified in the tested silicone condensation by each measurement instrument used in this study were diferente, indicating that the different measuring methods used can provide wrong results, and consequently, wrong indications.
10

Teoretická a skutečná přesnost měření fotogrammetrického systému Tritop / The theoretical and actual measurement accuracy of TRITOP photogrammetry system

Klus, Patrik January 2018 (has links)
This diploma thesis examines the impact of selected factors on the measurement accuracy of Tritop photogrammetry system and verifies the validity of theoretical predictive formulas. Primary attention is given to factors that are easily influenced by the inspector - namely number of captured images, shooting distance, number of scale bars and number of coded targets. In addition, experiments dealing with the measurement automation and the use of external color filter are also described in this thesis. Seven scale bars placed on a jig of cube shape were subject of the measurements (according to VDI/VDE 2634 standard). Two approaches were used in order to obtain measurement deviations – reference values, from which the measured data were subtracted to obtain deviations, were known due to the use of scale bars. Second approach consisted in evaluation of deviations from software Tritop Professional. The results showed that the number of photographs and shooting distance have the greatest impact on measurement accuracy of Tritop system. The accuracy was also influenced by number of coded targets in the scene or by use of the external green filter. Measured data were compared to the values obtained from predictive formulas. The results showed that the formula defined by the GOM company has a prediction accuracy of more than 96 %. However the formula is dependent on the input parameter called “Image accuracy” for which the value recommendations are made in this work. The results of this work can help predict measurement uncertainties more precisely and optimize the measurement methodology of Tritop photogrammetry system.

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