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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.
261

InSAR Simulations for SWOT and Dual Frequency Processing for Topographic Measurements

Masalias Huguet, Gerard 19 March 2019 (has links)
In Earth remote sensing precise characterization of the backscatter coefficient is important to extract valuable information about the observed target. A system that eliminates platform motion during near-nadir airborne observations is presented in this thesis, showing an improvement on the accuracy of measurements for a Ka- band scatterometer previously developed at Microwave Remote Sensing Laboratory (MIRSL). These very same results are used to simulate the reflectivity of such targets as seen from a spaceborne radar and estimate height errors based on mission-specific geometry. Finally, data collected from a dual-frequency airborne interferometer com- prised by the Ka-band system and an S-band radar is processed and analyzed to estimate forest heights.
262

Scaled Synthetic Aperture Rader Development

Schray, Jason Garvey 01 September 2016 (has links)
Several previous Cal Poly thesis projects involve synthetic aperture radar (SAR), automatic target recognition (ATR), and tracking. SAR data was either accessed from a publicly available database or generated using complex computer modeling software. The motivation for this dual thesis project is to design and construct a scaled SAR system to support Cal Poly radar projects. Ideally this is a low-cost, high resolution SAR architecture that produces raw range Doppler data for any desired target area. To that end, a scaled SAR system was successfully designed, built, and tested. The current SAR system, however, does not perform azimuthal compression and range cell migration correction. These functionalities can be pursued by future students joining the ongoing radar project. The system built for this thesis is a 1 GHz bandwidth SAR system. The system is comprised of analog/RF front end circuitry, two antennas, a mechanical rail platform, power supplies, an oscilloscope, and control and image processing software. This thesis covers the design and evaluation of the analog/radio frequency (RF) front end circuitry and signal processing software. RF amplifier integrated circuits (ICs) were evaluated for two purposes: increasing transmitted signal strength and improving system signal-to-noise ratio (SNR). A voltage-controlled oscillator’s (VCO) tuning characteristic and bandwidth were measured to verify its ability to support system specifications. A ramp generator circuit was designed, assembled and tested. Multiple ultra wide band (UWB) band pass filters were investigated for received signal image rejection. A low pass filter (LPF) was designed, assembled and tested for noise reduction. The overall system was tested with multiple known target locations. This thesis is a joint project with Ryan Green, MSEE student. To understand the entire project, refer to both thesis documents. The overall project is covered broadly in both papers but each report specializes in selected areas. Ryan Green’s thesis document focuses on the system control software, antenna design, and mechanical rail platform. This thesis document focuses on the RF circuitry, analog circuitry, and image processing. The introductory section introduces radar system concepts and the SAR system layout. The remaining sections describe component designs, component performance and system results.
263

Forecasting Inundation Extents in the Amazon Basin Using SRH-2D and HAND Based on the GEOGloWS ECMWF Streamflow Services

Edwards, Christopher Hyde 02 August 2021 (has links)
Floods are the most impactful natural disasters on earth, and reliable flood warning systems are critical for disaster preparation, mitigation, and response. The GEOGloWS ECMWF Streamflow Services (GESS) provide forecasted streamflow throughout the world. While forecasted discharge is essential to flood warning, forecasted inundation extents are required to understand and predict flood impact. In this research, I sought to expand GESS flood warning potential by generating inundation extents from streamflow forecasts. I compared Height Above Nearest Drainage (HAND), a method beneficial for flood mapping on a watershed scale, to a 2D hydrodynamic model, specifically Sedimentation and River Hydraulics – Two Dimension (SRH-2D), a method localized to specific areas of high importance. In three study areas in the Amazon basin, I validated HAND and SRH-2D flood maps against water maps derived from satellite SAR imagery. Specifically, I analyzed what features of an SRH-2D model were required to generate more accurate flood extents than HAND. I also analyzed the practicality of using SRH-2D for forecasting by comparing flood extents generated from simulating a complete forecast hydrograph to flood extents precomputed at predetermined, incremental flowrates. The SRH-2D models outperformed HAND, but their accuracy decreased at flowrates different than those used for calibration, limiting their reliability for forecasting and impact analysis. Based on this study, the key features necessary for a reliable SRH-2D model for forecasting include (1) a high-resolution DEM for an accurate representation of the floodplain, (2) correct representation of channel flow control, and (3) a channel bathymetry approximation and exit boundary rating curve that correctly predict water levels at a range of input flowrates. For forecasting practicality, the precomputed flood extents had accuracies comparable to the complete hydrograph simulations, showing their potential for estimating forecasted inundation extents. Future research should include (1) a more comprehensive analysis using existing SRH-2D models in areas with more bathymetry information and calibration data, (2) further assessment of the reliability of precomputed flood maps for forecasting applications, and (3) quantifying the effect of error in the streamflow forecasts on the accuracy of the resulting flood extents.
264

Nouveau modèle TLM thermique pour la dosimétrie numérique de structures fortement hétérogènes / New TLM thermal model for numerical dosimetry of highly heterogeneous structures

Makhlouf, Oualid 06 December 2016 (has links)
Depuis plusieurs années, le développement des technologies sans fil utilisant les ondes électromagnétiques dans différents milieux d’applications (télécommunications, médicales, militaires) ne cesse d’augmenter. Il devient donc nécessaire d’évaluer les effets de l’environnement sur les antennes en amont de leur conception afin d’optimiser la transmission entre les divers objets connectés. De plus, les études sur les systèmes utilisant les ondes électromagnétiques amènent à se poser un certain nombre de questions autour de l’interaction ondes/vivant, nous obligeant à considérer des modèles fortement hétérogènes tel que le corps humain.Face aux difficultés de mesures, la simulation permet de quantifier numériquement la puissance absorbée par les tissus au travers du DAS et l’élévation de la température correspondante. Dans ce domaine, la méthode TLM (Transmission Line Matrix) s’est révélée être particulièrement adaptée au calcul du DAS dans des structures fortement hétérogènes grâce à la colocalisation des champs au centre de la maille.Au cours de cette thèse, un outil basé sur la méthode TLM permettant d’effectuer des études dosimétriques en calculant le DAS et la température dans des milieux fortement hétérogènes a été développé. La première étape a été consacrée au développement d’un « module »pour calculer la DAS et la mise en place d’une interface pour lire les modèles voxélisés. Ensuite, un solveur thermique basé sur la TLM a été développé afin de simuler la température dans des milieux biologiques exposés aux ondes EM. Enfin, la comparaison avec le logiciel commercial CST a permis de valider notre outil et de l’appliquer par la suite pour étudier l’exposition d’une tête humaine au rayonnement d’un Smartphone modélisé par une PIFA fonctionnant à 900MHz / For several years, the development of the wireless technologies using the electromagnetic waves in various applications (telecommunications, medical, military …) does not stop increasing. Thus, it becomes necessary to evaluate the effects of the environment on antennas upstream to their conception to optimize the transmission between diverse connected objects. Furthermore, studies on the systems using the electromagnetic waves lead to ask a number of questions about waves/living interaction, obliging us to consider highly heterogeneous models such as human body.In front of difficulties of measures, the simulation allows to quantify numerically the power absorbed by tissues and the corresponding temperature rise. In this domain, the TLM method (Transmission Line Matrix) has proved to be particularly adapted to the simulation of the SAR in highly heterogeneous structures thanks to the co-localisation of the fields at the centre of mesh.In this thesis, a tool based on the TLM method to make dosimetrics studies by calculating the SAR and the temperature in highly heterogeneous media has been developed. The first step was dedicated to the development of a “module” to calculate the SAR and the implementation of an interface to read the voxelized models. Then, a thermal solver based on the TLM was developed in order to simulate the temperature in biological media exposed to the EM waves. Finally, the comparison with the commercial software CST allowed to validate our tool and to apply it afterward to study the exposure of a human head to the radiation of a Smartphone modelled by a PIFA antenna operating at 900MHz
265

Skutečné pokusy o etablování nových států či efemérní projekty? Případ Azawadu, republiky Logone a chalífátu Boko Haram / Full-fledged attempts at establishing new states or ephemeral projects? Case study Azawad, Republic of Logone and Boko Haram chaliphate

Čepičková, Lucie January 2017 (has links)
This diploma theses deals with attempts to declare independent states, namely in the case of the Republic of Azawad, Logone and Boko Haram caliphate, which originated between 2012 and 2015. Today, the existence of deviant forms of the state is nothing new, so there are many concepts and classifications that relate to this issue. For this theses will be the significant particular concept of states-within-states by Ian Spears and Paul Kingston and the classification by Bartosz Stanislawski, extended by authors Katarzyn Pełczyńska-Nałęc, Krzysztof Strachot and Maciej Falkowski. The subsequent description of the causes, the way of dominating the area and the events after the declaration of the independent state itself in the individual case studies will lead to a analysis of the way in which the area is administrated or the newly established institutions. Due to this analysis, it will be able to apply the states-within-states concept and Bartosz Stanislawki's classification and then determine whether this application is possible in all three cases. The last part of the work, which should confirm or disapprove the main hypothesis of the work, will then be used to evaluate whether the specific attempts are rather effective or ephemeral projects.
266

Comparison and Fusion of space borne L-, C- and X- Band SAR Images for Damage Identification in the 2008 Sichuan Earthquake

LAU, SIN WAI January 2011 (has links)
Remote sensing has been widely used in disaster management. However, application of optical imageries in damage detection is not always feasible for immediate damage assessment. In the case of the Sichuan earthquake in 2008, the damaged areas were covered by cloud and fog for most of the time. The all weather SAR imageries could instead provide information of the damaged area. Therefore, more efforts are needed to explore the usability of SAR data. In regards to this purpose, this research focuses on studying the ability of using various SAR data in damage identification through image classification, and furthermore the effectiveness of fusion of various sensors in classification is evaluated.   Three different types of SAR imagery were acquired over the heavily damaged zone Qushan town in the Sichuan earthquake. The 3 types of SAR data are ALOS PALSAR L-band, RADARSAT-1 C-band and the TerraSAR-X X- band imageries.   Maximum likelihood classification method is applied on the imageries.  Four classes: Water, collapsed area, built-up area and landslide area are defined in the study area. The ability of each band in identifying these four classes is studied and the overall classification accuracy is analysed. Furthermore, fusion of these 3 types of imageries is performed and the effectiveness and accuracy of image fusion classification are evaluated.   The results show that classification accuracy from individual SAR imagery is not ideal. The overall accuracy which PALSAR gives is 30.383%, RADARSAT-1 is 31.268% while TerraSAR-X only achieves 37.168%. Accuracy statistics demonstrate that TerraSAR-X performs the best in classifying these four classes.   SAR image fusion shows a better classification result. Double image fusion of PALSAR and RADARSAT-1, PALSAR and TerraSAR-X, and RADARSAT-1 and TerraSAR-X give an overall classification accuracy of 41.88%, 42.478% and 37.758% respectively. The result from triple image fusion even reaches 52.507%. They are all higher than the result given by the individual images.   The study illustrates that the VHR TerraSAR X band SAR data has a higher ability in classification of damages, and fusion of different band can improve the classification accuracy.
267

Exploitation of Digital Surface Models from Optical Satellites for the Identification of Buildings in High Resolution SAR Imagery

Ilehag, Rebecca January 2016 (has links)
Interpreting a Synthetic Aperture Radar (SAR) image and detecting buildings can be a difficult task visually. In order acquire an overview of an area that has been affected by a disaster, such as an earthquake, SAR is useful due to its independence of weather conditions and the time of the day. GeoRaySAR, a simulator that has been developed by German Aerospace Center (DLR) and the Technical University of Munich (TUM), uses prior knowledge about the geometry extracted, from e.g. a Digital Surface Model (DSM), in order to identify buildings in high resolution SAR data. The simulator has previously utilized DSMs generated from Light Detection And Ranging (LiDAR) data with a vertical and horizontal resolution of 0.1 meters and 1 meter respectively without vegetation. However, DSMs of such high quality is not available everywhere. The objective of this thesis is to evaluate DSMs generated from high-resolution optical data for identifying building in high resolution SAR data in GeoRaySAR. Specifically, images from the spaceborne sensor WorldView-2 have been utilized in this thesis for the extraction of the geometry. The DSMs have been preprocessed in terms of removal of vegetation and reduction of the noise level. The SAR images, acquired from TerraSAR-X, were utilized in GeoRaySAR in order to detect buildings with the assistance of the DSM. An image size limitation that existed in GeoRaySAR has been addressed by adding tiling, which is based on the size of the study scene. Normalized DSM (nDSM) can be determined by calculating the difference between a DSM and a DTM. A nDSM, that received some adjustments, was used as input to GeoRaySAR and compared with the results from the normal DSM. Study areas in three cities, Munich, London and Istanbul, have been used to determine the advantages and limitations of GeoRaySAR and the impact the quality of the DSM has on the building extraction results. The results indicate that building extents can be detected with DSMs generated from optical data with various success, dependent on the quality of the DSM and on which incidence angle the SAR image was acquired in. The ability to interpret a scene increases with the usage of DSMs of higher quality and with SAR images taken in less steep incidence angles. The building DSM depends heavily on the quality of the DTM, but indicates good results and little data loss in study scenes where the DTM successfully removed all objects above ground.
268

Implementación de un plan de vigilancia para el control y prevención frente al SARS-CoV2 en la Unidad Minera Las Águilas CIEMSA-2020

Huaracayo Perez, Wilbert 02 1900 (has links)
El presente estudio se desarrolló en la unidad minera las Águilas, la cual pertenece a la empresa CIEMSA. Ante la actual situación que se presenta ocasionada por la pandemia del SARS-CoV2, en este contexto se presentó la oportunidad de implementar un plan de vigilancia, prevención y control de SARS-CoV2 para la reanudación de actividades económicas, cumpliendo con los lineamientos, directivas y demás disposiciones establecidas por el Ministerio de Salud y protocolo sectorial del subsector minero del Ministerio de Energía y Minas para la vigilancia de la salud de los trabajadores con riesgo de exposición de SARS-CoV2 priorizando el cuidado de la vida y salud con riesgo de exposición en el reinicio de la actividades mineras. Aplicando la metodología de un estudio aplicativo porque su interés es la aplicación sobre una realidad circunstancial que tiene un alcance descriptivo que comprende la descripción de registro, análisis e interpretación de la naturaleza actual de los datos. Con la implementación de plan de vigilancia y protocolos durante el periodo de tiempo, obteniendo como resultado de un 96% del cumplimiento de la implementación y ejecución a las disposiciones establecidas normas nacionales estipulados así mismo se logra el reinicio de actividades con cero contagios y casos positivos en la Unidad Minera las Águilas.
269

Retrieval of biophysical parameters of agricultural crops using polarimetric sar interferometry

Ballester-Berman, J. David 17 September 2007 (has links)
No description available.
270

Chemical Elicitors of Systemic Acquired Resistance—Salicylic Acid and Its Functional Analogs

Tripathi, Diwaker, Raikhy, Gaurav, Kumar, Dhirendra 01 January 2019 (has links)
Any interaction of plants with phytopathogens involves the generation of various chemical molecules that are critical for activation of their defense machinery. One of the chemicals, salicylic acid (SA)induces systemic acquired resistance (SAR)in plants. The activation of SAR provides a broad-spectrum resistance against a wide range of related or unrelated pathogens. There has been considerable progress in the biochemical and molecular understanding of SAR activation in various plants. In addition, several chemicals including SA and its analogs are known to provide a direct or indirect defense against pathogens when applied to plants. Molecular mechanism of plant defense induced by synthetic chemical inducers is not very well understood. This review highlights the importance of salicylic acid and its most studied analog, Acibenzolar-S-methyl in inducing SAR and it also provides a description of other major chemical elicitors of plant defenses and their possible molecular mechanism.

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