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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

Doppler-only synthetic aperture radar

Chua, Cheng Lock Charles. 12 1900 (has links)
SAR has traditionally been performed using high-range resolution data. This thesis is a proof-of-concept that the imaging process can be performed using high-doppler resolution data. The system requires a simple continuous wave transmitter, and the signal returns are confined to a narrow band. High-doppler resolution data is collected along an isodoppler line for different perspectives of the target. This data, a sinogram, is equivalent to taking the Radon transform of the target. The Fourier transform of the sinogram from each perspective (at an angle eÌ ) gives a slice of the two-dimensional transform subtending an angle eÌ with the axis, with equally distributed points along the line. This results in a higher density of points near the centre. Some form of weighting is necessary. This weighting is part of the Filtered Backprojection algorithm to determine the Inverse Radon transform of the sinogram. The backprojection portion is a simple redistribution of data back along the original projection line. Images were modeled by delta functions to test the above algorithm. The main points noted were that the reconstructed image was a scaled version of the original image, and that the quality of the image improved when more perspectives of the target were taken.
2

An investigation into transcranial Doppler ultrasonography : observer agreement of variability of data in healthy volunteers and patients /

Shen, Qiaomei. January 2000 (has links) (PDF)
Thesis (M. Med. Sc.)--University of Queensland, 2002. / Includes bibliographical references.
3

Drop-size distributions as revealed by pulsed doppler radar

Wilson, Dean Andrew, 1938- January 1963 (has links)
No description available.
4

Investigating blood flow dynamics using Doppler optical coherence tomography

Moger, Julian January 2003 (has links)
No description available.
5

Right heart function in health and disease : a Doppler echocardiography and Doppler tissue imaging study /

Lindqvist, Per, January 2005 (has links)
Diss. (sammanfattning) Umeå : Umeå universitet, 2005. / Härtill 5 uppsatser.
6

The effect of temperature on the 0.296 ev. resonance of plutonium- 239

Lindstrom, Duaine G. January 1960 (has links)
Thesis (M.S.)--University of Michigan, 1960.
7

Contribuição dos exames ultrassonográficos convencional, Doppler e classificação Bi-Radis® na avaliação dos tumores mamários em cadelas

Souza, Priscilla Macedo de [UNESP] 17 August 2012 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:31:08Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-08-17Bitstream added on 2014-06-13T20:01:39Z : No. of bitstreams: 1 souza_pm_dr_botfmvz.pdf: 434841 bytes, checksum: 9a0c852b9c237f1cfb94020d68b747b7 (MD5) / Universidade Estadual Paulista (UNESP) / A ultrassonografia mamária em cadelas é uma importante técnica na avaliação tecidual, e distinção dos tumores benignos e malignos, favorecendo a conduta e prognóstico de cada paciente. O objetivo do trabalho foi avaliar a contribuição da técnica ultrassonográfica no modo-B, Doppler colorido, Doppler de Amplitude e Doppler espectral no diagnóstico dos tumores mamários em cadelas, a fim de correlacionar os resultados com o histopatológico, e classificar os tumores mamários de acordo com BI-RADS® (Breast Imaging and Reporting Data System) protocolo de classificação e padronização dos laudos ultrassonográficos da mama de mulher, proposto pelo Colégio Americano de Radiologia (ACR). Foram analisadas 117 mamas de 50 cadelas através do exame ultrassonográfico e posteriormente essas imagens foram classificadas pelo sistema BI-RADS® modificado e pela categoria de BI-RADS® modificado (categorias de 1 a 5). Diagnosticou se 9 tipos de tumores malignos. As principais características ultrassonográficas para a diferenciação dos tipos de tumores e indicativo de malignidade representando maior odds ratio (OR) foi a presença de microcalcificações no interior do nódulo (4,5 vezes), a sombra acústica posterior (4,0 vezes), presença de pelo menos 2 cistos (3,4 vezes). A descrição do BI-RADS® modificado mostrou se significativo para classificação de acordo com a malignidade e nos diferentes tipos de tumores. A neovascularização foi observada em 93% (55/59) dos casos de carcinoma complexo, e desses somente 34% (20/59) apresentaram detecção de das velocidades do fluxo sanguíneo no Doppler de Amplitude. As médias da... / A breast ultrasound in bitches is an important technique in evaluating tissue, and distinction of benign and malignant tumors, favoring the management and prognosis of each patient. The objective of this study was to evaluate the contribution of technical ultrasound B-mode, color Doppler, power Doppler and spectral Doppler in the diagnosis of mammary tumors in female dogs in order to correlate the results with histopathology, and classify breast tumors according with BI-RADS® (Breast Imaging Reporting and Data System) protocol classification and standardization of reports of female breast ultrasound, proposed by the American College of Radiology (ACR). We evaluated 117 breasts of 50 female dogs via ultrasonography and these images were subsequently classified by BI-RADS® category and the modified BI-RADS® modified (categories 1-5). 9 is diagnosed types of malignant tumors. The main sonographic features for the differentiation of tumor types and indicative of malignancy representing higher odds ratio (OR) was the presence of microcalcifications within the nodule (4.5 times), and posterior acoustic shadowing (4.0 times), presence at least two cysts (3.4 times). A description of the modified BI-RADS® showed significant for classification according to malignancy and in different types of tumors. Neovascularization was observed in 93% (55/59) of the carcinoma complex, and of these only... (Complete abstract click electronic access below)
8

Contribuição dos exames ultrassonográficos convencional, Doppler e classificação Bi-Radis® na avaliação dos tumores mamários em cadelas /

Souza, Priscilla Macedo de. January 2012 (has links)
Orientador: Maria Jaqueline Mamprim / Banca: Cibele Fiqueira Carvalho / Banca: Andrigo Barboza de Nardi / Banca: Maria Denise Lopes / Banca: Sheila Canevese Rahal / Resumo: A ultrassonografia mamária em cadelas é uma importante técnica na avaliação tecidual, e distinção dos tumores benignos e malignos, favorecendo a conduta e prognóstico de cada paciente. O objetivo do trabalho foi avaliar a contribuição da técnica ultrassonográfica no modo-B, Doppler colorido, Doppler de Amplitude e Doppler espectral no diagnóstico dos tumores mamários em cadelas, a fim de correlacionar os resultados com o histopatológico, e classificar os tumores mamários de acordo com BI-RADS® (Breast Imaging and Reporting Data System) protocolo de classificação e padronização dos laudos ultrassonográficos da mama de mulher, proposto pelo Colégio Americano de Radiologia (ACR). Foram analisadas 117 mamas de 50 cadelas através do exame ultrassonográfico e posteriormente essas imagens foram classificadas pelo sistema BI-RADS® modificado e pela categoria de BI-RADS® modificado (categorias de 1 a 5). Diagnosticou se 9 tipos de tumores malignos. As principais características ultrassonográficas para a diferenciação dos tipos de tumores e indicativo de malignidade representando maior odds ratio (OR) foi a presença de microcalcificações no interior do nódulo (4,5 vezes), a sombra acústica posterior (4,0 vezes), presença de pelo menos 2 cistos (3,4 vezes). A descrição do BI-RADS® modificado mostrou se significativo para classificação de acordo com a malignidade e nos diferentes tipos de tumores. A neovascularização foi observada em 93% (55/59) dos casos de carcinoma complexo, e desses somente 34% (20/59) apresentaram detecção de das velocidades do fluxo sanguíneo no Doppler de Amplitude. As médias da... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: A breast ultrasound in bitches is an important technique in evaluating tissue, and distinction of benign and malignant tumors, favoring the management and prognosis of each patient. The objective of this study was to evaluate the contribution of technical ultrasound B-mode, color Doppler, power Doppler and spectral Doppler in the diagnosis of mammary tumors in female dogs in order to correlate the results with histopathology, and classify breast tumors according with BI-RADS® (Breast Imaging Reporting and Data System) protocol classification and standardization of reports of female breast ultrasound, proposed by the American College of Radiology (ACR). We evaluated 117 breasts of 50 female dogs via ultrasonography and these images were subsequently classified by BI-RADS® category and the modified BI-RADS® modified (categories 1-5). 9 is diagnosed types of malignant tumors. The main sonographic features for the differentiation of tumor types and indicative of malignancy representing higher odds ratio (OR) was the presence of microcalcifications within the nodule (4.5 times), and posterior acoustic shadowing (4.0 times), presence at least two cysts (3.4 times). A description of the modified BI-RADS® showed significant for classification according to malignancy and in different types of tumors. Neovascularization was observed in 93% (55/59) of the carcinoma complex, and of these only... (Complete abstract click electronic access below) / Doutor
9

Velocidades de desplazamiento miocárdico en una muestra de individuos sin enfermedad cardiaca

Armendáriz Ferrari, José Carlos January 2003 (has links)
Las velocidades de desplazamiento miocárdico fueron estudiadas un una muestra de 140 individuos normales, con rango de edades de 1 mes a 94 años mediante el empleo de ecocardiografía doppler tisular técnica de examen recientemente desarrollada que permite el registro del espectro de velocidades del desplazamiento miocárdico las cuales son del rango de 6 a 24 cm/seg, este método ha sido propuesto para la evaluación de la función sistólica y diastólica se registraron las velocidades a nivel del anillo mitral ( pared lateral y septum interventricular) y del anillo tricuspídeo. En la diástole se registran 2 velocidades denominadas: diastólica temprana (EW) y diastólica tardía; en sístole a nivel del anillo mitral se registra una onda bifásica denominadas SW1 y SW2 en el anillo tricuspideo se registran en diástole 2 ondas similares a las del anillo mitral y en sístole se registran 2 ondas una, pre eyectiva de la cual no hay referencia y una onda sistólica monofásica. Los pacientes fueron distribuidos en grupos de 10 años con excepción de los menores de 1 año y mayores de 70 años que se reunieron en un solo respectivamente, calculándose valores promedio de cada parámetro. Las velocidades diastólicas tempranas registradas en el anillo mitral ( pared lateral y septum interventricular) muestran una conducta bimodal; En los primeros 3 grupos (individuos de 1 mes a 20 años), se evidencia un leve incremento de la velocidad, mientras que en los restantes 6 grupos (individuos de 21 a 94 años), se observa una notoria disminución de la velocidad con el aumento de la edad; Las velocidades diabólicas tempranas medidas en el anillo tricuspídeo muestran en todos los grupos una disminución progresiva con el aumento de la edad. Las velocidades diastólicas tardías registradas en el anillo mitral ( pared lateral y septum interventricular) muestran una conducta bimodal; En los primeros 3 grupos (individuos de 1 mes a 20 años), se evidencia una leve disminución de la velocidad, en los 6 grupos restantes, se aprecia un incremento progresivo de la velocidad con el aumento de la edad; La conducta de la velocidad diastólica tardía medida a nivel de anillo tricuspídeo muestra conducta similar. En la evaluación de las velocidades sistólicas a nivel del anillo mitral, se observó un leve incremento de la velocidad sistólica SW1 en los primeros 3 grupos (individuos de 1 mes a 20 años) y una disminución progresiva de la velocidad en los En los 6 grupos restantes (individuos de 21 a 94 años). La velocidad sistólica SW2 presenta un incremento con el aumento de la edad. A nivel del anillo tricuspídeo las velocidades son mayores que las registradas en el anillo mitral. La velocidad pre eyectiva muestra un leve incremento con la edad en toda la muestra; La velocidad Sistólica muestra muy leve incremento en los primeros 3 grupos (individuos de 1 mes a 20 años) y una discreta disminución progresiva en los En los 6 grupos restantes (individuos de 21 a 94 años). Los hallazgos de nuestro estudio permiten cualificar las modificaciones que el corazón presenta con la progresión de la edad proponiéndose como patrón de normalidad referencial para estudios posteriores que evalúen patología; por otro lado los hallazgos del anillo tricuspídeo se proponen como criterio adicional para la evaluación de la función ventricular derecha. · Médico cardiólogo asistente del Hospital nacional Hipólito Unanue · Médico cardiólogo asistente del Hospital Militar Central · Médico cardiólogo de Centro de Diagnóstico CDX · Profesor de medicina (cardiología) de la Universidad Nacional Federico Villar / Tesis de segunda especialidad
10

Doppler Tracking

Thomas, Christopher Jacob 11 December 2015 (has links)
This study addresses the development of a methodology using the Doppler Effect for high-resolution, short-range tracking of small projectiles and vehicles. Minimal impact on the design of the moving object is achieved by incorporating only a transmitter in it and using ground stations for all other components. This is particularly useful for tracking objects such as sports balls that have configurations and materials that are not conducive to housing onboard instrumentation. The methodology developed here uses four or more receivers to monitor a constant frequency signal emitted by the object. Efficient and accurate schemes for filtering the raw signals, determining the instantaneous frequencies, time synching the frequencies from each receiver, smoothing the synced frequencies, determining the relative velocity and radius of the object and solving the nonlinear system of equations for object position in three dimensions as a function of time are developed and described here.

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