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Cannon, Robert William. "Automated Spectral Identification of Materials using Spectral Identity Mapping." Cleveland State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=csu1377031729.
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Elling, Volker Wilhelm. "A spectral method for mapping dataflow graphs." Thesis, Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/8161.
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Blanchette, Damon Arthur. "Adaptive Spectral Mapping for Real-Time Dispersive Refraction." Digital WPI, 2012. https://digitalcommons.wpi.edu/etd-theses/110.
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Spectral rendering, or the synthesis of images by taking into account the wavelengths of light, allows effects otherwise impossible with other methods. One of these effects is dispersion, the phenomenon that creates a rainbow when white light shines through a prism. Spectral rendering has previously remained in the realm of off-line rendering (with a few exceptions) due to the extensive computation required to keep track of individual light wavelengths. Caustics, the focusing and de-focusing of light through a refractive medium, can be interpreted as a special case of dispersion where all the wavelengths travel together. This thesis extends Adaptive Caustic Mapping, a previously proposed caustics mapping algorithm, to handle spectral dispersion. Because ACM can display caustics in real-time, it is quite amenable to be extended to handle the more general case of dispersion. A method is presented that runs in screen-space and is fast enough to display plausible dispersion phenomena in real-time at interactive frame rates.
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Earle, Alissa M. "Spectral mapping and long-term seasonal evolution of Pluto." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/117915.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2018.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 169-186).
NASA's New Horizons mission has provided a wealth of new data about the Pluto system, including detailed surface geology and volatile distribution maps revealing striking latitudinal and longitudinal variations. We begin by studying the methane distribution and surface colors using data from New Horizons' Ralph/MVIC instrument. From this study we find that Pluto's equatorial region shows a broader diversity of terrains and more stark longitudinal contrasts than the more homogeneous north polar region. Pluto's south polar region is currently in constant shadow and thus was not observed by New Horizons. We consider how this diversity formed and survived in the context of Pluto's extreme Milancovid cycles and resultant "super seasons". Over timescales of roughly 3 million years Pluto's obliquity varies by 23 degrees (between 103 degrees and 126 degrees) while its longitude of perihelion regresses. This pair of cycles create "super season" epochs where one pole experiences a short intense summer and long winter in constant darkness, while the other experiences a short winter and much longer, but less intense summer. Through thermal modeling and volatile sublimation and deposition modeling we determined that Pluto's high obliquity creates conditions at its equator that favor albedo contrast and can support them on million year timescales more effectively than Pluto's polar regions can. Finally, we look ahead to a possible next step in small body spacecraft exploration, a study of Apophis during its 2029 close approach to Earth. Since the earlier portion of this thesis focused on the encounter, data collection, and scientific analysis portion of a spacecraft mission (New Horizons), we go full circle by exploring the early stage of the
by Alissa M. Earle.
Ph. D.
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Spalt, Taylor Brooke. "Constrained Spectral Conditioning for the Spatial Mapping of Sound." Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/70868.
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In aeroacoustic experiments of aircraft models and/or components, arrays of microphones are utilized to spatially isolate distinct sources and mitigate interfering noise which contaminates single-microphone measurements. Array measurements are still biased by interfering noise which is coherent over the spatial array aperture. When interfering noise is accounted for, existing algorithms which aim to both spatially isolate distinct sources and determine their individual levels as measured by the array are complex and require assumptions about the nature of the sound field.
This work develops a processing scheme which uses spatially-defined phase constraints to remove correlated, interfering noise at the single-channel level. This is achieved through a merger of Conditioned Spectral Analysis (CSA) and the Generalized Sidelobe Canceller (GSC). A cross-spectral, frequency-domain filter is created using the GSC methodology to edit the CSA formulation. The only constraint needed is the user-defined, relative phase difference between the channel being filtered and the reference channel used for filtering. This process, titled Constrained Spectral Conditioning (CSC), produces single-channel Fourier Transform estimates of signals which satisfy the user-defined phase differences. In a spatial sound field mapping context, CSC produces sub-datasets derived from the original which estimate the signal characteristics from distinct locations in space. Because single-channel Fourier Transforms are produced, CSC's outputs could theoretically be used as inputs to many existing algorithms. As an example, data-independent, frequency-domain beamforming (FDBF) using CSC's outputs is shown to exhibit finer spatial resolution and lower sidelobe levels than FDBF using the original, unmodified dataset. However, these improvements decrease with Signal-to-Noise Ratio (SNR), and CSC's quantitative accuracy is dependent upon accurate modeling of the sound propagation and inter-source coherence if multiple and/or distributed sources are measured.
In order to demonstrate systematic spatial sound mapping using CSC, it is embedded into the CLEAN algorithm which is then titled CLEAN-CSC. Simulated data analysis indicates that CLEAN-CSC is biased towards the mapping and energy allocation of relatively stronger sources in the field, which limits its ability to identify and estimate the level of relatively weaker sources. It is also shown that CLEAN-CSC underestimates the true integrated levels of sources in the field and exhibits higher-than-true peak source levels, and these effects increase and decrease respectively with increasing frequency. Five independent scaling methods are proposed for correcting the CLEAN-CSC total integrated output levels, each with their own assumptions about the sound field being measured. As the entire output map is scaled, these do not account for relative source level errors that may exist. Results from two airfoil tests conducted in NASA Langley's Quiet Flow Facility show that CLEAN-CSC exhibits less map noise than CLEAN yet more segmented spatial sound distributions and lower integrated source levels. However, using the same source propagation model that CLEAN assumes, the scaled CLEAN-CSC integrated source levels are brought into closer agreement with those obtained with CLEAN.Ph. D.
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Behjat, Hamid. "Statistical Parametric Mapping of fMRI data using Spectral Graph Wavelets." Thesis, Linköpings universitet, Medicinsk informatik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-81143.
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In typical statistical parametric mapping (SPM) of fMRI data, the functional data are pre-smoothed using a Gaussian kernel to reduce noise at the cost of losing spatial specificity. Wavelet approaches have been incorporated in such analysis by enabling an efficient representation of the underlying brain activity through spatial transformation of the original, un-smoothed data; a successful framework is the wavelet-based statistical parametric mapping (WSPM) which enables integrated wavelet processing and spatial statistical testing. However, in using the conventional wavelets, the functional data are considered to lie on a regular Euclidean space, which is far from reality, since the underlying signal lies within the complex, non rectangular domain of the cerebral cortex. Thus, using wavelets that function on more complex domains such as a graph holds promise. The aim of the current project has been to integrate a recently developed spectral graph wavelet transform as an advanced transformation for fMRI brain data into the WSPM framework. We introduce the design of suitable weighted and un-weighted graphs which are defined based on the convoluted structure of the cerebral cortex. An optimal design of spatially localized spectral graph wavelet frames suitable for the designed large scale graphs is introduced. We have evaluated the proposed graph approach for fMRI analysis on both simulated as well as real data. The results show a superior performance in detecting fine structured, spatially localized activation maps compared to the use of conventional wavelets, as well as normal SPM. The approach is implemented in an SPM compatible manner, and is included as an extension to the WSPM toolbox for SPM.
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Alvarez, Manuela. "Mapping forest habitats in protected areas by integrating LiDAR and SPOT Multispectral Data." Thesis, KTH, Geoinformatik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-189199.
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KNAS (Continuous Habitat Mapping of Protected Areas) is a Metria AB project that produces vegetation and habitat mapping in protected areas in Sweden. Vegetation and habitat mapping is challenging due to its heterogeneity, spatial variability and complex vertical and horizontal structure. Traditionally, multispectral data is used due to its ability to give information about horizontal structure of vegetation. LiDAR data contains information about vertical structure of vegetation, and therefore contributes to improve classification accuracy when used together with spectral data. The objectives of this study are to integrate LiDAR and multispectral data for KNAS and to determine the contribution of LiDAR data to the classification accuracy. To achieve these goals, two object-based classification schemes are proposed and compared: a spectral classification scheme and a spectral-LiDAR classification scheme. Spectral data consists of four SPOT-5 bands acquired in 2005 and 2006. Spectral-LiDAR includes the same four spectral bands from SPOT-5 and nine LiDAR-derived layers produced from NH point cloud data from airborne laser scanning acquired in 2011 and 2012 from The Swedish Mapping, Cadastral and Land Registration Authority. Processing of point cloud data includes: filtering, buffer and tiles creation, height normalization and rasterization. Due to the complexity of KNAS production, classification schemes are based on a simplified KNAS workflow and a selection of KNAS forest classes. Classification schemes include: segmentation, database creation, training and validation areas collection, SVM classification and accuracy assessment. Spectral-LiDAR data fusion is performed during segmentation in eCognition. Results from segmentation are used to build a database with segmented objects, and mean values of spectral or spectral-LiDAR data. Databases are used in Matlab to perform SVM classification with cross validation. Cross validation accuracy, overall accuracy, kappa coefficient, producer’s and user’s accuracy are computed. Training and validation areas are common to both classification schemes. Results show an improvement in overall classification accuracy for spectral-LiDAR classification scheme, compared to spectral classification scheme. Improvements of 21.9 %, 11.0 % and 21.1 % are obtained for the study areas of Linköping, Örnsköldsvik and Vilhelmina respectively.
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Stanislavova, Milena. "Spectral mapping theorems and invariant manifolds for infinite-dimensional Hamiltonian systems /." free to MU campus, to others for purchase, 2000. http://wwwlib.umi.com/cr/mo/fullcit?p9988702.
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Praeger, Matthew. "Development and spatio-spectral mapping of a capillary high harmonic source." Thesis, University of Southampton, 2008. https://eprints.soton.ac.uk/66192/.
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This work describes the development and operation of a capillary based High Harmonic Generation (HHG) system. Using this system a coherent beam of soft x-rays is generated, studied and applied. A series of experiments was then undertaken in order to deepen our knowledge of the HHG process and to optimise the performance of the source. Notable contributions made to the field are: A novel laser mode quality measuring device. (Laser mode quality strongly affects the efficiency of the capillary launch). A study of the spectral output of the system as a function of gas pressure, laser power, and laser spectral phase. An analysis technique for recovering spatially-resolved spectral information about a beam by studying the Fresnel diffraction pattern produced at an array of apertures. A study of pulse compression using cascaded quadratic nonlinearity for spectral broadening.
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Zhao, Yonghui. "Image segmentation and pigment mapping of cultural heritage based on spectral imaging /." Online version of thesis, 2008. http://hdl.handle.net/1850/7050.
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Andrew, Colin Murray. "Computation and display of EEG spectral and event-related desynchronization topographic maps." Thesis, University of Cape Town, 1992. http://hdl.handle.net/11427/26326.
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Li, Shanghuo, Junzhi Wang, Zhi-Yu Zhang, Min Fang, Juan Li, Jiangshui Zhang, Junhui Fan, Qingfeng Zhu, and Fei Li. "Millimetre spectral line mapping observations towards four massive star-forming H ii regions." OXFORD UNIV PRESS, 2017. http://hdl.handle.net/10150/623847.
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We present spectral line mapping observations towards four massive star-forming regions Cepheus A, DR21S, S76E and G34.26+0.15 - with the IRAM 30-m telescope at the 2 and 3 mm bands. In total, 396 spectral lines from 51 molecules, one helium recombination line, 10 hydrogen recombination lines and 16 unidentified lines were detected in these four sources. An emission line of nitrosyl cyanide (ONCN, 14(0), 14-13(0), (13)) was detected in G34.26+0.15, as the first detection in massive star-forming regions. We found that c-C3H2 and NH2D show enhancement in shocked regions, as suggested by the evidence of SiO and/or SO emission. The column density and rotational temperature of CH3CN were estimated with the rotational diagram method for all four sources. Isotope abundance ratios of C-12/C-13 were derived using HC3N and its C-13 isotopologue, which were around 40 in all four massive star-forming regions and slightly lower than the local interstellar value (similar to 65). The N-14/N-15 and O-16/O-18 abundance ratios in these sources were also derived using the double isotopic method, which were slightly lower than in the local interstellar medium. Except for Cep A, the S-33/S-34 ratios in the other three targets were derived, which were similar to that in the local interstellar medium. The column density ratios of N(DCN)/N(HCN) and N( DCO+)/N(HCO+) in these sources were more than two orders of magnitude higher than the elemental [D]/[H] ratio, which is 1.5 x 10(-5). Our results show that the later stage sources, G34.26+0.15 in particular, present more molecular species than earlier stage sources. Evidence of shock activity is seen in all stages studied.
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McCall, David S. "Expanding the Application of Spectral Reflectance Measurement in Turfgrass Systems." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/77971.
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Light reflectance from plants can be used as a non-invasive predictor of health and yield for many cropping systems, and has been investigated to a lesser extent with managed turfgrass systems. The frequent agronomic inputs associated with maintaining golf course grasses allow for exceptional stand quality under harsh growing conditions, but often expend resources inefficiently, leading to either stand loss or unnecessary inputs in localized areas. Turfgrass researchers have adopted some basic principles of light reflectance formerly developed for cropping systems, but field radiometric-derived narrow-band algorithms for turfgrass-specific protocols are lacking. Research was conducted to expand the feasibility of using radiometry to detect various turfgrass stressors and improve speed and geographic specificity of turfgrass management. Methods were developed to detect applied turfgrass stress from herbicide five days before visible symptoms developed under normal field growing conditions. Soil volumetric water content was successfully estimated using a water band index of creeping bentgrass canopy reflectance. The spectral reflectance of turfgrass treated with conventional synthetic pigments was characterized and found to erroneously influence plant health interpretation of common vegetation indices because of near infrared interference by such pigments. Finally, reflectance data were used to estimate root zone temperatures and root depth of creeping bentgrass systems using a gradient of wind velocities created with turf fans. Collectively, these studies provide a fundamental understanding of several turfgrass-specific reflectance algorithms and support unique opportunities to detect stresses and more efficiently allocate resources to golf course turf.Ph. D.
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Pekesin, Burcu Fatma. "Mineral Mapping In Oymaagac (beypazari &." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12606027/index.pdf.
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The aim of this study is to extract information about mineral distribution and
percentages of Oymaagaçgranitoid (Beypazari-Ankara) by using remote sensing techniques. Two methods are applied during the studies which are spectral analysis and Crosta techniques. Spectral measurements are done for fresh and weathered samples collected at 32 locations. Mineral percentages are calculated using spectral mixture analysis for each sample by considering main, accessory and secondary mineral content of granodiorite. A total of 10 endmembers for fresh samples and 15 for weathered samples are used. USGS spectral library data is utilized through the analyses. For Crosta technique (image analysis) the multispectral ASTER satellite image is used. Five alteration minerals are discriminated and their maps are generated during this analysis. Interpretation and comparison of the results of both methods and testing these results with the existing petrographical and geochemical data indicate that: 1) according to the results of both spectral analyses and Crosta technique a zonation is not observed in the granitoid, 2) comparison of the results for alteration minerals of these two analyses are partly compatible but not exactly similar, 3) Results of spectral analysis do not fit geochemical nor modal analyses because of inconsistency of the data sets.
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Yetkin, Erdem. "Alteration Mapping By Remote Sensing: Application To Hasandag &." Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/1090927/index.pdf.
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Certain alteration minerals are used to identify the hydrothermally altered rocks. Potassic, phyllic (sericitic), propylitic, argillic and silicification are main alteration types observed in volcanic rocks. The role of remote sensing in alteration mapping is the differentiation of the minerals that are unique for In this study, Landsat TM 5 images are used. General alteration trend in the area is mapped by conventional methods of color composite, band rationing, principal component analysis and multi-linear regression analysis. Detailed mineral mapping carried on by using the United States Geological Survey (USGS) spectral library data. Spectral reflectances of selected minerals are analyzed according to the TM band intervals and appropriate band ratios are selected. TM bands 1,2,3,4,5 and 7 are used. Outputs of mineral maps are investigated for zonal distribution. Mineral maps that are obtained by the mineral separation method reveal that the youngest volcanic complex Hasandag is poorly altered. Instead, Keçiboyduran, Melendiz and Tepekö
y volcanic complexes are found to be highly altered with the pattern of clay dominant in the center and increasing oxidation towards flanks. Also the alteration along the previously mapped buried faults is a proof that the method can provide information about the alteration source.
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Kliman, Douglas Hartley. "Rule-based classification of hyper-temporal, multi-spectral satellite imagery for land-cover mapping and monitoring." Diss., The University of Arizona, 1996. http://hdl.handle.net/10150/187473.
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A rule-based classification model was developed to derive land-cover information from a large set of hyper-temporal, multi-spectral satellite imagery encompassing the state of Arizona. The model uses Advanced Very High Resolution Radiometer (AVHRR) imagery and the 30-minute digital elevation model (DEM) from the EROS Data Center (EDC) Conterminous U.S. AVHRR Biweekly Composites. Sixty one images from 1990, 1991 and 1992 were analyzed using the Brown & Lowe (1973) Natural Vegetative Communities of Arizona map to identify temporal patterns of Normalized Difference Vegetation Index (NDVI) and thermal measurements for 13 land-cover classes. Fifteen characteristic layers were created to represent the spectral, thermal and temporal properties of the data set. These layers were inputs for the rule-based classification model. The model was run on three years of data, creating three single year land-cover maps. The modeling effort showed that NDVI, thermal and DEM characteristics are useful for discerning land-cover classes. The single year land-cover maps showed that the rule-based model could not detect land-cover change between years. The single year maps were combined to create a summary land-cover map. This map differs from the Brown and Lowe map in the shape, proportional size and spatial distribution of land-cover polygons. The rule-based model can discern more land-cover classes than spectral cluster classification. Ground observations and an aerial video was used to assess map accuracy. The same proportion of agreement was observed between the ground observations, the Brown and Lowe map, and the summary land-cover map. Agreement was higher between video and the summary map than between video and the Brown and Lowe map. With further refinements to the input data set, classification model rules and field accuracy assessment, higher levels of agreement can be expected. Overall results show that rule-based classification of hyper-temporal, multi-spectral satellite imagery is a desirable method for mapping global land-cover.
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Shao, Yang Walsh Stephen J. "Mapping and modeling the urban landscape in Bangkok, Thailand physical-spectral-spatial relations of population-environmental interactions /." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2007. http://dc.lib.unc.edu/u?/etd,1181.
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Thesis (Ph. D.)--University of North Carolina at Chapel Hill, 2007.Title from electronic title page (viewed Mar. 27, 2008). "... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Geography." Discipline: Geography; Department/School: Geography.
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Rolfson, David, and University of Lethbridge Faculty of Arts and Science. "Collection of endmembers and their separability for spectral unmixing in rangeland applications." Thesis, Lethbridge, Alta. : University of Lethbridge, Dept. of Geography, 2010, 2010. http://hdl.handle.net/10133/2527.
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Rangelands are an important resource to Alberta. Due to their size, mapping
rangeland features is difficult. However, the use of aerial and satellite data for mapping
has increased the area that can be studied at one time. The recent success in applying
hyperspectral data to vegetation mapping has shown promise in rangeland classification.
However, classification mapping of hyperspectral data requires existing data for input
into classification algorithms. The research reported in this thesis focused on acquiring a
seasonal inventory of in-situ reflectance spectra of rangeland plant species (endmembers)
and comparing them to evaluate their separability as an indicator of their suitability for
hyperspectral image classification analysis. The goals of this research also included
determining the separability of species endmembers at different times of the growing
season.
In 2008, reflectance spectra were collected for three shrub species (Artemisia
cana, Symphoricarpos occidentalis, and Rosa acicularis), five rangeland grass species
native to southern Alberta (Koeleria gracilis, Stipa comata, Bouteloua gracilis,
Agropyron smithii, Festuca idahoensis) and one invasive grass species (Agropyron
cristatum). A spectral library, built using the SPECCHIO spectral database software,
was populated using these spectroradiometric measurements with a focus on vegetation
spectra.
Average endmembers of plant spectra acquired during the peak of sample
greenness were compared using three separability measures – normalized Euclidean
distance (NED), correlation separability measure (CSM) and Modified Spectral Angle
Mapper (MSAM) – to establish the degree to which the species were separable. Results
were normalized to values between 0 and 1 and values above the established thresholds
indicate that the species were not separable . The endmembers for Agropyron cristatum,
Agropyron smithii, and Rosa acicularis were not separable using CSM (threshold =
0.992) or MSAM (threshold = 0.970). NED (threshold = 0.950) was best able to separate
species endmembers.
Using reflectance data collected throughout the summer and fall, species
endmembers obtained within two-week periods were analyzed using NED to plot their
separability. As expected, separability of sample species changed as they progressed
through their individual phenological patterns. Spectra collected during different solar
zenith angles were compared to see if they affected the separability measures. Sample
species endmembers were generally separable using NED during the periods in which
they were measured and compared. However, Koeleria gracilis and Festuca idahoensis
endmembers were inseparable from June to mid-August when measurements were taken
at solar zenith angles between 25° – 30° and 45° – 60°. However, between 30° and 45°,
Bouteloua gracilis and Festuca idahoensis endmembers, normally separable during other
solar zenith angles, became spectrally similar during the same sampling period.
Findings suggest that the choice of separability measures is an important factor
when analyzing hyperspectral data. The differences observed in the separability results
over time also suggest that the consideration of phenological patterns in planning data
acquisition for rangeland classification mapping has a high level of importance.xii, 93 leaves : ill. (some col.) ; 29 cm
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Gu, Degui. "Incorporating structural information into interpretation of satellite images of forests /." Thesis, Connect to this title online; UW restricted, 1998. http://hdl.handle.net/1773/6818.
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Khiry, Manal Awad. "Spectral Mixture Analysis for Monitoring and Mapping Desertification Processes in Semi-arid Areas in North Kordofan State, Sudan." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2007. http://nbn-resolving.de/urn:nbn:de:swb:14-1187262045124-42224.
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Multi-temporal remotely sensed data (MSS, TM and ETM+)were used for monitoring and mapping the desertification processes in North Kordofan State, Sudan.A liear mixture model (LMM) was adopted to analyse and the desertification proccesses by using the image endmembers. interpretation of ancillary data and field observation was adopted to verfiy the role of human impacts in the temporal changes in the study area. The findings of the study proved the powerfull of remotely sensed data in monitoring and mapping the desertification processes and come out with valuable recommendations which could contribute positively in reducing desert encroachment in the area.
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Hassan, Waqar Ul. "Pixel Based and Object Oriented Multi-spectral Remotely Sensed Data Analysis for Flood Risk Assessment and Vulnerability Mapping." Thesis, Linköpings universitet, Institutionen för datavetenskap, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-64011.
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Geographical information system with remotely sensed data can be instrumental in many ways for disaster management and post disaster rehabilitation. During last few decades the usage of remotely sensed data has extensively increased, although image interpretation tools are not highly accurate but still considered as fast, reliable and useful way to get information from imagery. Disaster assessment, management and rehabilitation are always creates challenge for experts. Population growth, expansion in settlements either in the rural or in the urban areas bring more problems not only for the humans but it also affect the global environment Such global changes on the massive scale disturbs the ecological processes. GIS along with Remote sensing data can change the whole scenario in very short period of time. All the departments concerning to strategic disaster planning process can share their information by using the single platform, so for this purpose spatial database can be helpful by providing the spatial data in digital format to the department concerned. Spatial phenomena can be observed by using different image analysis techniques and the resultant thematic map display the spatial variations and changes that describe the particular phenomenon whether it was any disaster or change in soil type or vegetation type. Remotely sensed data like aerial, satellite and radar images are very useful for disaster management strategy formulation process. Integration of GIS and remote sensing proved itself the best especially for land-use, land-cover mapping. For this purpose pixel based, sub-pixel based, pre-field and object oriented classification approach are being in use around the world. But thematic maps created from image analyzed by using object oriented classifiers contain more accuracy than any other techniques.
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DiGirolamo, Paul A. "A comparison of change detection methods in an urban environment using LANDSAT TM and ETM+ satellite imagery a multi-temporal, multi-spectral analysis of Gwinnett County, GA 1991-2000 /." unrestricted, 2005. http://etd.gsu.edu/theses/available/etd-07242006-110800/.
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Thesis (M.A.)--Georgia State University, 2005.Title from title screen. Zhi-Yong Yin, committee chair; Paul Knapp, Truman Hartshorn, committee members. Electronic text (135 p. : col. ill., col. maps)) : digital, PDF file. Description based on contents viewed Aug. 2, 2007. Includes bibliographical references (p. 125-133).
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Bayer, Anita. "Methodological developments for mapping soil constituents using imaging spectroscopy." Phd thesis, Universität Potsdam, 2012. http://opus.kobv.de/ubp/volltexte/2013/6439/.
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Climatic variations and human activity now and increasingly in the future cause land cover changes and introduce perturbations in the terrestrial carbon reservoirs in vegetation, soil and detritus. Optical remote sensing and in particular Imaging Spectroscopy has shown the potential to quantify land surface parameters over large areas, which is accomplished by taking advantage of the characteristic interactions of incident radiation and the physico-chemical properties of a material.
The objective of this thesis is to quantify key soil parameters, including soil organic carbon, using field and Imaging Spectroscopy. Organic carbon, iron oxides and clay content are selected to be analyzed to provide indicators for ecosystem function in relation to land degradation, and additionally to facilitate a quantification of carbon inventories in semiarid soils. The semiarid Albany Thicket Biome in the Eastern Cape Province of South Africa is chosen as study site. It provides a regional example for a semiarid ecosystem that currently undergoes land changes due to unadapted management practices and furthermore has to face climate change induced land changes in the future.
The thesis is divided in three methodical steps. Based on reflectance spectra measured in the field and chemically determined constituents of the upper topsoil, physically based models are developed to quantify soil organic carbon, iron oxides and clay content. Taking account of the benefits limitations of existing methods, the approach is based on the direct application of known diagnostic spectral features and their combination with multivariate statistical approaches. It benefits from the collinearity of several diagnostic features and a number of their properties to reduce signal disturbances by influences of other spectral features.
In a following step, the acquired hyperspectral image data are prepared for an analysis of soil constituents. The data show a large spatial heterogeneity that is caused by the patchiness of the natural vegetation in the study area that is inherent to most semiarid landscapes. Spectral mixture analysis is performed and used to deconvolve non-homogenous pixels into their constituent components. For soil dominated pixels, the subpixel information is used to remove the spectral influence of vegetation and to approximate the pure spectral signature coming from the soil. This step is an integral part when working in natural non-agricultural areas where pure bare soil pixels are rare. It is identified as the largest benefit within the multi-stage methodology, providing the basis for a successful and unbiased prediction of soil constituents from hyperspectral imagery. With the proposed approach it is possible (1) to significantly increase the spatial extent of derived information of soil constituents to areas with about 40 % vegetation coverage and (2) to reduce the influence of materials such as vegetation on the quantification of soil constituents to a minimum.
Subsequently, soil parameter quantities are predicted by the application of the feature-based soil prediction models to the maps of locally approximated soil signatures. Thematic maps showing the spatial distribution of the three considered soil parameters in October 2009 are produced for the Albany Thicket Biome of South Africa. The maps are evaluated for their potential to detect erosion affected areas as effects of land changes and to identify degradation hot spots in regard to support local restoration efforts. A regional validation, carried out using available ground truth sites, suggests remaining factors disturbing the correlation of spectral characteristics and chemical soil constituents.
The approach is developed for semiarid areas in general and not adapted to specific conditions in the study area. All processing steps of the developed methodology are implemented in software modules, where crucial steps of the workflow are fully automated. The transferability of the methodology is shown for simulated data of the future EnMAP hyperspectral satellite. Soil parameters are successfully predicted from these data despite intense spectral mixing within the lower spatial resolution EnMAP pixels.
This study shows an innovative approach to use Imaging Spectroscopy for mapping of key soil constituents, including soil organic carbon, for large areas in a non-agricultural ecosystem and under consideration of a partially vegetation coverage. It can contribute to a better assessment of soil constituents that describe ecosystem processes relevant to detect and monitor land changes. The maps further provide an assessment of the current carbon inventory in soils, valuable for carbon balances and carbon mitigation products.Klimatische und anthropogene Faktoren verursachen bereits jetzt und verstärkt in Zukunft Änderungen der Landbedeckung und Landnutzung natürlicher Ökosysteme, die sich direkt auf die terrestrischen Kohlenstoffspeicher in Vegetation, Böden und biogenen Resten auswirken. Optische Fernerkundung und im Besonderen die Abbildende Spektroskopie sind etablierte Methoden, die basierend auf der charakteristischen Wechselwirkung der Sonnenstrahlung mit physikalisch-chemischen Materialeigenschaften eine quantitative Abschätzung degradationsrelevanter Parameter der Landoberfläche erlauben. Das Ziel dieser Arbeit ist die Quantifizierung maßgeblicher Bodeninhaltsstoffe unter Verwendung von Feld- und abbildender Spektroskopie. Dabei stehen organischer Kohlenstoff, Eisenoxide und Ton im Fokus der Betrachtung, da ihre Gehalte im Boden als Indikatoren für Landoberflächenveränderungen verwendet werden können und ihre Analyse gleichzeitig eine direkte Abschätzung des bodengebundenen Kohlenstoffreservoirs ermöglicht. Das semiaride Albany Thicket in der östlichen Kapprovinz Südafrikas wurde als Arbeitsgebiet ausgewählt. Es steht beispielhaft für einen Naturraum, der sich gegenwärtig durch nicht angepasste Landnutzung verändert und der voraussichtlich auch in Zukunft hochfrequenten, durch den Klimawandel bedingten, Schwankungen unterliegen wird. Die Arbeit ist in drei methodische Schritte untergliedert. Die einzelnen Prozessierungsschritte der entwickelten Methodik sind in Softwaremodulen umgesetzt, in denen die wichtigsten Schritte voll automatisiert sind. Unter Verwendung von im Feld gemessenen Reflektanzspektren und chemisch bestimmten Gehalten der obersten Bodenschicht wird ein Modell zur Bestimmung der drei ausgewählten Bodenparameter erstellt. Der gewählte Ansatz basiert auf der direkten Verwendung bekannter spektraler Merkmale in Verbindung mit multivariaten Verfahren. In nächsten Schritt werden die großflächig aufgenommenen Hyperspektraldaten vorbereitet, die die für semiaride Räume typischen kleinräumigen Landbedeckungsänderungen wiederspiegeln. Auf subpixel-Basis erlaubt eine spektrale Entmischungsanalyse die Zerlegung nicht homogener Bildspektren in ihre spektralen Bestandteile. Dadurch kann für Pixel, die signifikante Anteile an unbedecktem Boden aufweisen, die reine spektrale Signatur des Bodens in Näherung bestimmt werden. Diese Vorgehensweise kennzeichnet einen wesentlichen Gewinn, da er eine Anwendung auf heterogene Naturräume abseits landwirtschaftlicher Flächen erlaubt, die Ausdehnung des Gültigkeitsbereichs, für den Bodeneigenschaften vorhergesagt werden können, deutlich steigert und den Einfluss von Fremdmaterialien wie Vegetation auf eine Bestimmung minimiert. Daran anknüpfend erfolgt die Vorhersage von Bodeninhaltsstoffen. Die räumliche Verteilung von organischem Kohlenstoff, Eisenoxiden und der Tongehalte wie sie sich im Oktober 2009 im südafrikanischen Albany Thicket darstellte, wurde in thematischen Karten erfasst. Sie wurden hinsichtlich ihres Potentials ausgewertet, Bereiche zu erkennen, die in Folge von Landbedeckungsänderungen von Erosion betroffen sind. Die vorliegende Arbeit zeigt einen innovativen Ansatz zur Verwendung Abbildender Spektroskopie zur Kartierung wichtiger Bodeneigenschaften in einem semiariden Naturraum. Die Methodik liefert einen Beitrag zur verbesserten Abschätzung ökosystemrelevanter Bodeneigenschaften sowie eine direkte Abschätzung vorhandener Kohlenstoffspeicher im Boden, Parameter, die zur Erkennung und Überwachung von Landbedeckungsänderungen verwendet werden können.
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Sugianto, Biological Earth & Environmental Science UNSW. "Multi-angular hyperspectral data and its influences on soil and plant property measurements: spectral mapping and functional data analysis approach." Awarded by:University of New South Wales. Biological, Earth and Environmental Science, 2006. http://handle.unsw.edu.au/1959.4/25531.
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This research investigates the spectral reflectance characteristics of soil and vegetation using multi-angular and single view hyperspectral data. The question of the thesis is ???How much information can be obtained from multi-angular hyperspectral remote sensing in comparison with single view angle hyperspectral remote sensing of soil and vegetation???? This question is addressed by analysing multi-angular and single view angle hyperspectral remote sensing using data from the field, airborne and space borne hyperspectral sensors. Spectral mapping, spectral indices and Functional Data Analysis (FDA) are used to analyse the data. Spectral mapping has been successfully used to distinguish features of soil and cotton with hyperspectral data. Traditionally, spectral mapping is based on collecting endmembers of pure pixels and using these as training areas for supervised classification. There are, however, limitations in the use of these algorithms when applied to multi-angular images, as the reflectance of a single ground unit will differ at each angle. Classifications using six-class endmembers identified using single angle imagery were assessed using multi-angular Compact High Resolution Imaging Spectrometer (CHRIS) imagery, as well as a set of vegetation indices. The results showed no significant difference between the angles. Low nutrient content in the soil produced lower vegetation index values, and more nutrients increased the index values. This research introduces FDA as an image processing tool for multi-angular hyperspectral imagery of soil and cotton, using basis functions for functional principal component analysis (fPCA) and functional linear modelling. FDA has advantages over conventional statistical analysis because it does not assume the errors in the data are independent and uncorrelated. Investigations showed that B-splines with 20-basis functions was the best fit for multi-angular soil spectra collected using the spectroradiometer and the satellite mounted CHRIS. Cotton spectra collected from greenhouse plants using a spectrodiometer needed 30-basis functions to fit the model, while 20-basis functions were sufficient for cotton spectra extracted from CHRIS. Functional principal component analysis (fPCA) of multi-angular soil spectra show the first fPCA explained a minimum of 92.5% of the variance of field soil spectra for different azimuth and zenith angles and 93.2% from CHRIS for the same target. For cotton, more than 93.6% of greenhouse trial and 70.6% from the CHRIS data were explained by the first fPCA. Conventional analysis of multi-angular hyperspectral data showed significant differences exist between soil spectra acquired at different azimuth and zenith angles. Forward scan direction of zenith angle provides higher spectral reflectance than backward direction. However, most multi-angular hyperspectral data analysed as functional data show no significant difference from nadir, except for small parts of the wavelength of cotton spectra using CHRIS. There is also no significant difference for soil spectra analysed as functional data collected from the field, although there was some difference for soil spectra extracted from CHRIS. Overall, the results indicate that multi-angular hyperspectral data provides only a very small amount of additional information when used for conventional analyses.
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Schafer, Ingo. "Orthogonal and Nonorthogonal Expansions for Multi-Level Logic Synthesis for Nearly Linear Functions and their Application to Field Programmable Gate Array Mapping." PDXScholar, 1992. https://pdxscholar.library.pdx.edu/open_access_etds/1339.
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The growing complexity of integrated circuits and the large variety of architectures of Field Programmable Gate Arrays (FPGAs) require sophisticated logic design tools. In the beginning of the eighties the research in logic design was concentrated on the development of fast two-level AND-OR logic minimizers like the well known ESPRESSO. However, most logic functions have a smaller and often faster circuit realization as a multi-level circuit. Thus, synthesis tools emerged for the minimization of the circuit area in a multi-level realization. Most of these synthesis tools are based on the "unate paradigm". Therefore, the synthesis methods are only advantageous for functions having a minimal circuit realization based on AND-OR gates. However, many common functions have a minmal circuit realization having a mix of AND, OR and EXOR gates like counters, adders, multipliers, and parity generators. Therefore, the design of such functions with synthesis tools based on the "unated paradigm" is very inefficient. Circuits incorporating the EXOR gate have received less attention than AND-OR circuits because the EXOR gate was perceived as slower and larger in terms of its circuit realization than the AND and the OR gate. However, the upcoming of Field Programmable Gate Arrays (FPGAs) like the Xilinx Table-Look-Up (TLU) architecture the Actel ACTâ„¢ series and the CLi 6000 series from Concurrent Logic, which allow the realization of the EXOR gate with the same speed and circuit cost as the AND and OR gate, eliminates the disadvantages of the EXOR gate over the AND and OR gate. Thus, there is a strong need for logic synthesis tools that take advantage of EXOR gates. The mapping to the new FPGAs recently obtained an increased interest. The developed synthesis algorithms for FPGAs are based on the mapping and restructuring of the Directed Acyclic Graph (DAG) representation of the logic function. Even though the new FPGAs allow the realization of the EXOR gate without any speed and circuit size penalty in comparison to the AND and OR gate, the synthesis methods have been based on the "unate paradigm". To overcome the disadvantages of the current logic synthesis tools with respect to (nearly) linear functions and FPGA synthesis, this dissertation introduces an extended theory of spectral methods for multiple-valued input, incompletely specified binary output logic. The spectral methods have not been popular in logic synthesis because of their four major drawbacks: (1) the computational complexity, especially if no Fast Transform exists, (2) the memory requirement to store the function in the necessary minterm representation, (3) they cannot take efficiently advantage of incompletely specified functions, (4) suitable only for few applications in logic synthesis. To overcome the two last stated drawbacks, this dissertation introduces the T spectrum. The T spectrum separates the information obtained for the specified and not specified parts of the underlying function. Thus, it is possible to determine directly the contribution of the specified and the not specified part of the function to a single spectral coefficient. Moreover, the T spectrum is an extension of the known spectra like Walshtype, Adding, Arithmetic, and Reed-Muller spectra to any orthogonal and nonorthogonal transform describing logic functions. Thus, transforms can be constructed that describe certain gate structures, as for example the realizable functions of a FPGA macrocell. This allows the development of special synthesis algorithms for the different types of FPGA architectures. As an exemplification of this method, a complete multi-level synthesis algorithm is introduced for the circuit realization with multiplexer modules, which form the basic macrocell of the Actel ACfâ„¢ FPGA series. Additionally, this dissertation presents the classification of the applications of spectral methods in logic synthesis into three categories: (1) The decomposition of logic functions based on the information obtained by the computation of a single spectrum. As an example the linearization procedure developed by Karpowsky is generalized to incompletely specified multi-output Boolean functions. The linearization procedure is based on the computation of the Rademacher-Walsh spectrum with a following decomposition of the underlying function based on high value spectral coefficients. (2) The circuit realization of a logic function based on the repetitive application of (1). This synthesis method is exemplified by an multi-level synthesis algorithm for multiplexer gates. (3) The realization of a logic function as an AND-EXOR circuit based on a GF 2 (Galois Field (2)) spectrum. The GF 2 transforms exhibit the property that they describe a realization of the underlying function as a two-level AND-EXOR circuit. The Multiple-Valued Input Kronecker Reed-Muller (MIKRM) form is introduced as an application of GF 2 transforms. To overcome the drawbacks of spectral methods concerning the computational complexity and high memory requirements, this dissertation presents a computation method for spectra from disjoint representations. The introduced application of the disjoint cube representation and the Ordered Decision Diagrams for the computation of spectra proves to be an ideal concept. Thus, this dissertation presents general synthesis methods based on new spectral methods that overcome the deficiencies of current logic synthesis methods with respect to the synthesis for FPGAs as well as the computational complexity and memory requirements of spectral methods.
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Qie, Guangping. "MAPPING AND UNCERTAINTY ANALYSIS OF URBAN VEGETATION CARBON DENSITY BY COMBINING SPATIAL MODELING, DE-SHADOW & SPECTRAL UNMIXING ANALYSIS." OpenSIUC, 2019. https://opensiuc.lib.siu.edu/dissertations/1671.
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Weng, Fenqing. "Mapping and Assessing Urban Impervious Areas Using Multiple Endmember Spectral Mixture Analysis: A Case Study in the City of Tampa, Florida." Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/4253.
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The advance in remote sensing technology helps people more easily assess urban growth. In this study, the utility of multiple endmember spectral mixture analysis (MESMA) is examined in a sub-pixel analysis of Landsat Thematic Mapper (TM) imagery to map urban physical components in Tampa, FL. The three physical components of urban land cover (LC): impervious surface, vegetation and soil, were compared using the proposed MESMA with a traditional spectral mixture analysis (SMA). MESMA decomposes each pixel to address the heterogeneity of urban LC characteristic by allowing the number and types of endmembers to vary on a per pixel basis. This study generated 642 spectral mixture models of 2-, 3-, and 4-endmembers for each pixel to estimate the fractions of impervious surface, vegetation, soil, and shade in the study area with a constraint of lowest root mean square error (RMSE). A comparative analysis of the impervious surface areas (ISA) mapped with MESMA and SMA demonstrated that MESMA produced more accurate results of mapping urban physical components than those by SMA. With the multiyear Landsat TM data, we quantified sub-pixel %ISA and the %ISA changes to assess urban growth in the City of Tampa, Florida during the past twenty years. The experimental results demonstrate that the MESMA approach is effective in mapping and monitoring urban land use/land cover changes using moderate-resolution multispectral imagery at a sub-pixel level.
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Lau, Ian Christopher. "Regolith-landform and mineralogical mapping of the White Dam Prospect, eastern Olary Domain, South Australia, using integrated remote sensing and spectral techniques." Title page, abstract and table of contents only, 2004. http://hdl.handle.net/2440/37972.
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The research contained within this thesis was directed at examining the spectral properties of regolith-dominated terrains using airborne and proximal hyperspectral instruments. The focus of the investigation was to identify the mineralogy of the regolith and determine if surficial materials were indicative of the underlying bedrock in the regolithdominated terrain of the eastern Olary Domain, South Australia. The research area was constrained to a 250 km2 area around the Cu-Au mineralisation of the White Dam Prosect. Integrated remote sensing, using airborne hyperspectral datasets (HyMap), Landsat imagery and gamma-ray spectroscopy data, was performed to map regolith-landforms and extract information on surficial materials. Detailed calibration of the HyMap dataset, using a modified model-based/empirical line calibration technique, was required prior to information extraction. The White Dam area was able to be divided into: alluvial regolith-dominated; in situ regolith-dominated; and bedrock-dominated terrains, based on mineralogical interpretations of the regolith, using the remotely sensed hyperspectral data. Alluvial regions were characterised by large abundances of vegetation and soils with a hematite-rich mineralogy. Highly weathered areas of in situ material were discriminated by the presence of goethite and kaolinite of various crystallinities, whereas the bedrock-dominated regions displayed white mica-/muscovite-rich mineralogy. Areas flanking bedrock exposures commonly consisted of shallow muscovite-rich soils containing regolith carbonate accumulations. Traditional mineral mapping processes were performed on the HyMap data and were able to extract endmembers of regolith and other surficial materials. The Mixture Tuned Matched Filter un-mixing process was successful at classifying regolith materials and minerals. Spectral indices performed on masked data were effective at identifying the key regolith mineralogical features of the HyMap imagery and proved less time consuming than un-mixing processes. Processed HyMap imagery was able to identify weathering halos, highlighted in mineralogical changes, around bedrock exposures. Proximal spectral measurements and XRD analyses of samples collected from the White Dam Prospect were used to create detailed mineralogical dispersion maps of the surface and costean sections. Regolith materials of the logged sections were found to correlate with the spectrally-derived mineral dispersion profiles. The HyLogger drill core scanning instrument was used to examine the mineralogy of the fresh bedrock, which contrasted with the weathering-derived near-surface regolith materials. The overall outcomes of the thesis showed that hyperspectral techniques were useful for charactering the mineralogy of surficial materials and mapping regolith-landforms.Thesis (Ph.D.)--School of Earth & Environmental Sciences, 2004.
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Li, Qi. "Intermittency of Global Solar Radiation over Reunion island : Daily Mapping Prediction Model and Multifractal Parameters." Thesis, La Réunion, 2018. http://www.theses.fr/2018LARE0016/document.
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Les îles tropicales sont soumises à un ennuagement hétérogène et changeant rapidement. Par ailleurs, elles ont une ressource solaire importante mais significativement variable d’un jour à l’autre. Dans le sud-ouest de l’océan indien (SWIO), La Réunion fait partie de ces îles tropicales ayant un potentiel solaire colossal mais fortement intermittent. Dans cette étude, nous proposons une nouvelle approche de prévision déterministe des cartes journalières rayonnement solaire (SSR), basée sur quatre modèles de régression linéaire : une régression linéaire multiple (MLR), une régression en composantes principales (PCR), une régression des moindres carrés (PLSR) et une régression pas à pas (stepwise--SR). Ces quatre régressions sont appliquées sur les données satellites SARAH-E (CM SAF) à 5km de résolution entre 2007 et 2016, en vue d’en effectuer la prévision. Pour obtenir de meilleures performances, nous proposons d'inclure les paramètres multi-fractale (H,C_1 et α) comme nouveaux paramètres prédictifs. Ceux-ci sont obtenus à partir de l'analyse de l'intermittence du SSR basée sur la méthode d’analyse d’ordre spectral arbitraire de Hilbert. Cette analyse qui est une extension de la transformation d’Hilbert Huang (HHT) est utilisée afin d’estimer l’exposant d’échelle ξ(q). On effectue la combinaison d’une décomposition en mode empirique et de l’analyse spectrale de Hilbert (EMD + HSA). Dans une première étape, l’analyse multi-fractale est appliquée sur une mesure du SSR d'une seconde échelle à partir d'un pyranomètre SPN1 à Moufia en 2016. La moyenne infra journalière, journalière et saisonnière de la structure multi-fractale a été dérivée, et la loi d’échelle d’exposants ξ(q) a été analysée. Dans une seconde partie, l’analyse de l’intermittence est effectuée sur les mesures du SSR, d'une période d’une minute, à partir le réseau de SPN1 contenant 11 stations en 2014. Les modèles spatiaux pour toutes les stations avec les paramètres multi-fractales H,C_1 et α sont mis en évidence. La variabilité de la largeur du spectre de singularité est considérée pour étudier l'intermittence spatiale et la multi-fractalité dans l'échelle quotidienne et l'échelle saisonnière. Sur la base de ces analyses d'intermittence faites sur les mesures de plusieurs stations, les paramètres multi-fractaux universels (H,C_1 et α) pourraient être choisis comme de nouveaux prédicteurs afin d’indiquer les propriétés multi-fractales du SSRDue to the heterogeneous and rapidly-changing cloudiness, tropical islands, such as Reunion Island in the South-west Indian Ocean (SWIO), have significant solar resource that is highly variable from day-to-day. In this study, we propose a new approach for deterministic prediction of daily surface solar radiation (SSR) maps based on four linear regression models: multiple linear regression (MLR), principal component regression (PCR), partial least squares regression (PLSR), and stepwise regression (SR), that we have applied on the SARAH-E@5km satellite data (CM SAF) for the period during 2007-2016. To improve the accuracy of prediction, the multifractal parameters (H,C_1 and α) are proposed to include as new predictors in the predictive model. These parameters are obtained from the analysis of SSR intermittency based on arbitrary order Hilbert spectral analysis. This analysis is the extension of Hilbert Huang Transform (HHT) and it is used to estimate the generalized scaling exponent ξ(q). It is the combination of the Empirical Mode Decomposition and Hilbert spectral analysis (EMD+HSA). In a first step, the multifractal analysis is applied onto one-second SSR measurements form a SPN1 pyranometer in Moufia in 2016. The mean sub-daily, daily and seasonal daily multifractal patterns are derived, and the scaling exponent ξ(q) is analyzed. In a second step, the intermittency study is conducted on one-minute SSR measurements from a SPN1 network with 11 stations in 2014. The spatial patterns for all the stations with the multifractal parameters H,C_1 and α are shown. The variability of singularity spectrum width is considered to study the spatial intermittency at the daily and seasonal scale. Based on this intermittency analysis from measurements at several stations, the universal multifractal parameters (H,C_1 and α) could be taken as new predictors for indicating the multifractal properties of SSR
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Droog, Arisca. "Remote Sensing for Detecting and Mapping Flowering Rush: A Case Study in the Ottawa National Wildlife Refuge (ONWR), Ohio." Bowling Green State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1349900740.
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Deshpande, Shrirang. "Improving observability in experimental analysis of rotating systems." University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1414750479.
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Kazemeini, Sayed Hesammoddin. "Seismic Investigations at the Ketzin CO2 Injection Site, Germany: Applications to Subsurface Feature Mapping and CO2 Seismic Response Modeling." Doctoral thesis, Uppsala universitet, Geofysik, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-105032.
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3D seismic data are widely used for many different purposes. Despite different objectives, a common goal in almost all 3D seismic programs is to attain better understanding of the subsurface features. In gas injection projects, which are mainly for Enhanced Oil Recovery (EOR) and recently for environmental purposes, seismic data have an important role in the gas monitoring phase. This thesis deals with a 3D seismic investigation at the CO2 injection site at Ketzin, Germany. I focus on two critical aspects of the project: the internal architecture of the heterogeneous Stuttgart reservoir and the detectability of the CO2 response from surface seismic data. Conventional seismic methods are not able to conclusively map the internal reservoir architecture due to their limited seismic resolution. In order to overcome this limitation, I use the Continuous Wavelet Transform (CWT) decomposition technique, which provides frequency spectra with high temporal resolution without the disadvantages of the windowing process associated with the other techniques. Results from applying this technique reveal more of the details of sand bodies within the Stuttgart Formation. The CWT technique also helps to detect and map remnant gas on the top of the structure. In addition to this method, I also show that the pre-stack spectral blueing method, which is presented for the first time in this research, has an ability to enhance seismic resolution with fewer artifacts in comparison with the post-stack spectral blueing method. The second objective of this research is to evaluate the CO2 response on surface seismic data as a feasibility study for CO2 monitoring. I build a rock physics model to estimate changes in elastic properties and seismic velocities caused by injected CO2. Based on this model, I study the seismic responses for different CO2 injection geometries and saturations using one dimensional (1D) elastic modeling and two dimensional (2D) acoustic finite-difference modeling. Results show that, in spite of random and coherent noises and reservoir heterogeneity, the CO2 seismic response should be strong enough to be detectable on surface seismic data. I use a similarity-based image registration method to isolate amplitude changes due to the reservoir from amplitude changes caused by time shifts below the reservoir. In support of seismic monitoring using surface seismic data, I also show that acoustic impedance versus Poisson’s ratio cross-plot is a suitable attribute for distinguishing gas-bearing sands from brine-bearing sands.CO2SINK Project
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Tsiminaki, Vagia. "Appearance Modelling for 4D Representations." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAM083/document.
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Ces dernières années ont vu l'émergence de la capture des modèles spatio-temporels (modélisation 4D) à partir d'images réelles, avec de nombreuses applications dans les domaines de post-production pour le cinéma, la science des sports, les études sociales, le divertissement, l'industrie de la publicité. A partir de plusieurs séquences vidéos, enregistrées à partir de points de vue variés, la modélisation 4D à partir de vidéos utilise des modèles spatio-temporels pour extraire des informations sur la géométrie et l'apparence de scènes réelles, permettant de les enregistrer et de les reproduire. Cette thèse traite du problème de la modélisation d'apparence.La disponibilité des donnée d'images offre de grands potentiels pour les reconstructions haute fidélité, mais nécessite des méthodes plus élaborées. En outre, les applications du monde réel nécessitent des rendus rapides et des flux réduits de données. Mais l'obtention de représentations d'apparence compactes, indépendantes du point de vue, et à grande résolution est toujours un problème ouvert.Pour obtenir ces caractéristiques, nous exprimons l'information visuelle de l'objet capturé dans un espace de texture commun. Les observations multi-caméra sont considérées comme des réalisations de l'apparence commune et un modèle linéaire est introduit pour matérialiser cette relation. Le modèle linéaire d'apparence proposé permet une première étude du problème de l'estimation d'apparence dans le cas multi-vue et expose les sources variées de bruit et les limitations intrinsèques du modèle.Basé sur ces observations, et afin d'exploiter l'information visuelle de la manière la plus efficace, nous améliorons la méthode en y intégrant un modèle de super-résolution 2D. Le modèle simule le procédé de capture d'image avec une concaténation d'opérations linéaires, générant les observation d'image des différents points de vue et permettant d'exploiter la redondance. Le problème de super-résolution multi-vue résultant est résolu par inférence bayésienne et une représentation haute-résolution d'apparence est fournie permettant de reproduire la texture de l'objet capturé avec grand détail.La composante temporelle est intégrée par la suite au modèle pour permettre d'y recouper l'information visuelle commune sous-jacente. En considérant des petits intervalles de temps ou l'apparence de l'objet ne change pas drastiquement, une représentation super-résolue cohérente temporellement est introduite. Elle explique l'ensemble des images de l'objet capturé dans cet intervalle. Grâce à l'inférence statistique Bayésienne, l'apparence construite permet des rendus avec une grande précision à partir de point de vue nouveau et à des instants différent dans l'intervalle de temps prédéfini.Pour améliorer l'estimation d'apparence d'avantage, l'inter-dépendance de la géométrie et de la photométrie est étudiée et exploitée. Les modélisations de la géométrie et de l'apparence sont unifiées dans le framework de super-résolution permettant une amélioration géométrique globale, ce qui donne à son tour une amélioration importante de l'apparence.Finalement pour encoder la variabilité de l'apparence dynamique des objets subissant plusieurs mouvements, une représentation indépendante du point de vue s'appuyant sur l'analyse en composantes principales est introduite. Cette représentation décompose la variabilité sous-jacente d'apparence en texture propres et déformations propres. La méthode proposée permet de reproduire les apparences de manière précise avec des représentation compactes. Il permet également l'interpolation et la complétion des apparences.Cette étude montre que la représentation compacte, indépendante du point de vue, et super-résolue proposée permet de confronter les nouvelles réalités du problème de modélisation d'apparence. Elle représente un contribution vers des représentations d'apparence 4D haute-qualité et ouvre de nouvelles directions de recherche dans ce domaineCapturing spatio-temporal models (4D modelling) from real world imagery has received a growing interest during the last years urged by the increasing demands of real-world applications and the tremendous amount of easily accessible image data. The general objective is to produce realistic representations of the world from captured video sequences. Although geometric modelling has already reached a high level of maturity, the appearance aspect has not been fully explored. The current thesis addresses the problem of appearance modelling for realistic spatio-temporal representations. We propose a view-independent, high resolution appearance representation that successfully encodes the high visual variability of objects under various movements.First, we introduce a common appearance space to express all the available visual information from the captured images. In this space we define the representation of the global appearance of the subject. We then introduce a linear image formation model to simulate the capturing process and to express the multi-camera observations as different realizations of the common appearance. Identifying that the principle of Super-Resolution technique governs also our multi-view scenario, we extend the image generative model to accommodate it. In our work, we use Bayesian inference to solve for the super-resolved common appearance.Second, we propose a temporally coherent appearance representation. We extend the image formation model to generateimages of the subject captured in a small time interval. Our starting point is the observation thatthe appearance of the subject does not change dramatically in a predefined small time interval and the visual information from each view and each frame corresponds to the same appearance representation.We use Bayesian inference to exploit the visual redundant as well as the hidden non-redundant information across time, in order to obtain an appearance representation with fine details.Third, we leverage the interdependency of geometry and photometry and use it toestimate appearance and geometry in a joint manner. We show that by jointly estimating both, we are able to enhance the geometry globally that in turn leads to a significant appearance improvement.Finally, to further encode the dynamic appearance variability of objects that undergo several movements, we cast the appearance modelling as a dimensionality reduction problem. We propose a view-independent representation which builds on PCA and decomposesthe underlying appearance variability into Eigen textures and Eigen warps. The proposed framework is shown to accurately reproduce appearances with compact representations and to resolve appearance interpolation and completion tasks
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Fiorio, Peterson Ricardo. "Dados radiométricos obtidos nos níveis terrestres e orbital na avaliação de solos." Universidade de São Paulo, 2002. http://www.teses.usp.br/teses/disponiveis/11/11140/tde-29102002-155935/.
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As áreas agrícolas vêm se tornando cada vez mais tecnificadas, onde o conhecimento das características físicas, químicas e mineralógicas dos solos se torna imprescindível para maximizar a produtividade. O Brasil possui uma grande extensão territorial, sendo que a maior parte não possui mapas de solos compatíveis com as necessidades agrícolas. Torna-se necessário fornecer subsídios à pesquisa pedológica referente ao aperfeiçoamento de técnicas que venham auxiliar os levantamentos de solos, tornando-os mais ágeis e econômicos. Para tanto, foram traçados os seguintes objetivos: caracterizar o comportamento espectral de solos nos níveis de campo, laboratório e orbital; correlacionar as alterações dos solos ao longo de topossequências com o caráter espectral; verificar a separabilidade das unidades de mapeamento e quantificar atributos dos solos através das respostas radiométricas; avaliar a eficiência prática da técnica. O trabalho foi conduzido em Barra Bonita, SP, onde predominam diferentes unidades de solos tais como LATOSSOLOS, ARGISSOLOS, CAMBISSOLOS e NITOSSOLOS com texturas de arenosas a muito argilosas. Na área foram demarcados pontos para amostragem em forma de grade (100 x 100 m). Todos os pontos de coleta foram georreferenciados, foram realizadas tradagens nas profundidades 0-20 e 80-100 cm. As amostras de terra foram encaminhadas ao laboratório para análises físicas, químicas. Foram obtidos dados espectrais através de espectroradiômetro em laboratório e campo. Foi realizado um mapa de solos detalhado pelo método convencional, incluindo a caracterização de perfis. Através dos dados espectrais obtidos nos níveis orbital e laboratório foram geradas equações discriminantes para os solos e equações lineares de regressão múltipla para vários atributos do solo. Os atributos dos solos foram comparados com valores estimados pelas equações e os valores determinados nas análises de laboratório para verificar a veracidade dos dados espectrais e a variabilidade da metodologia proposta. Na medida em que ocorrem alterações dos solos ao longo de uma topossequência, o comportamento espectral detectado pelos sensores, se altera. A análise descritiva das curvas espectrais descritas em literatura fornece poucos detalhes na discriminação de solos. É possível discriminar solos por sensor terrestre e orbital com 81 e 40 % de acerto respectivamente. A estimativa de teores de ferro por sensores terrestre e orbital auxilia na classificação de solos. É possível quantificar atributos do solo como areia, argila e ferro por sensores em laboratório, e, com menor índice de significância por sensores orbitais.The agricultural areas are becoming more and more technified, where the knowledge of the physical, chemical and mineralogical characteristics of soils becomes indispensable to maximize crop productivity. Brazil possesses a great territorial extension, and most of the areas do not possess soil maps compatible with the agricultural needs. Modern technological improvements signal the necessity of supplying data to soil research, especially those areas regarding soil survey, with the objective of turning soil survey more agile and economic. The following objectives were traced: characterize the spectral behavior of soils in field, laboratory and orbital levels; correlate the alterations of soils along toposequences with the spectral character; verify the discrimination of mapping units and quantify attributes of the soils through their spectral responses; evaluate the practical efficiency of the technique. The work was done in Barra Bonita, SP, where Oxisol, Alfisol, Inceptisol e Ultisol with textures of sandy to very loamy dominate. In the study area, samples were taken following a 100 x 100 m grid. All the points were georeferenced and soil samples were obtained in the depths 0-20 and 80-100 cm. The soil samples were taken to the laboratory for physical and chemical analyses. After that, the spectral data were obtained using a spectroradiometer in laboratory, field and orbital levels. A detailed soil maps was done by the conventional method, including the characterization of profiles. Through the spectral data obtained in the orbital and laboratory levels, discriminant equations were generated for the soils and linear equations of multiple regression for several attributes of the soil. The soil attributes were compared with values quantified by the equations and values determined in laboratory analyses to verify the accuracy of the spectral data and the variability of the methodology proposal. As the soils modifications occur along a toposequence, the spectral behavior detected by the sensors becomes different. The descriptive analysis of the spectral curves described in literature supplies few details of soil discrimination. It is possible to discriminate soils by terrestrial and orbital sensors with 81 and 40% of success, respectively. The estimation of the iron content by terrestrial and orbital sensors aids in the classification of soils. It is possible to quantify attributes of the soil as sand, clay and iron using a sensor in the laboratory, and, with smaller accuracy by orbital sensors.
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Schwanzer, Miroslav. "Studium vlivu akustických podnětů na člověka." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2012. http://www.nusl.cz/ntk/nusl-374608.
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The thesis deals with EEG signals, their description, methods of quantitative analysis and the processes in time-frequency domains, or power spectrums. The relationsheep between brain electrical activity and acustic stimuli (Mozart´s “Sonata K448”) was studied using EEG analysis in relation to sound impulses from replayed extracts of. The proposed experiment protocol included recording of EEG of volunteers. In order to visualize and analyze the data, the software with the graphic user interface was created, which enables topological mapping of brain activity and its vizualization in the time-frequency domain.
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Dotto, André Carnieletto. "Funções de pedotransferência do solo: Estimativa por radiometria." Universidade Federal de Santa Maria, 2012. http://repositorio.ufsm.br/handle/1/5562.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorThe traditional soil analysis many techniques are used in order to determine the physical and chemical properties of the soil. The radiometry appears as a promising alternative technique in the analysis of soil properties. This technique has demonstrated great potential for identification and quantification of certain properties of the soil. It is a non-destructive and non-polluting tool, with the ability to collect data on large spatial dimensions with relative speed. The radiometry may in cases be simpler than the traditional analysis of the soil and on various occasions, more accurately. The main objective of this study was to determine pedotransfer functions to soil properties based on radiometric data. It was observed that the heterogeneity of the soil decreases the accuracy of the models, however it was possible to construct prediction functions for the content of sand, silt, clay and soil organic matter from the radiometry with a level of prediction models acceptable. Considering that, in the prediction of soil properties using radiometry, there is no reagents spending and less resource invested beyond the analysis time shorter than the traditional analysis, the results were promising.
Na análise tradicional do solo muitas técnicas são utilizadas na tentativa de determinar suas propriedades físicas e químicas. A radiometria aparece como uma técnica alternativa e promissora na análise de propriedades do solo. Essa técnica tem demonstrado grande potencial na identificação e quantificação de determinadas propriedades do solo. Trata-se, de uma ferramenta não destrutiva, não poluidora, com capacidade de coleta de dados em grandes dimensões espaciais com relativa velocidade. A radiometria pode, em muitos casos, ser mais simples do que a análise tradicional do solo e em várias ocasiões, mais precisa. O principal objetivo desse trabalho foi determinar funções de pedotransferência para as propriedades do solo tendo como base os dados da radiometria. Observou-se que a heterogeneidade do solo diminui a precisão dos modelos, porém foi possível construir funções de predição para o teor de argila, areia, silte e matéria orgânica do solo a partir da radiometria com um nível de predição dos modelos aceitável. Considerando que, na predição das propriedades do solo utilizando a radiometria, não há gastos com reagentes e menos recursos investidos além do tempo de análise menor que a análise tradicional, os resultados apresentados foram promissores.
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Tan, Ke. "Convolutional and recurrent neural networks for real-time speech separation in the complex domain." The Ohio State University, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu1626983471600193.
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Blatný, Michal. "Spektrální analýza EEG signálu." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2011. http://www.nusl.cz/ntk/nusl-219237.
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Master’s thesis deal about electroencefalography, measurement EEG signals and analysis measuermed signals. Project contains two basis practical parts. Firts part contain two PC’s programs that’s are used to fundamental analysis to frequence-domain and visual display of brain mapping created with Matlab. Second chapter of practical parts includes two PC’s programs created with LabView. First of them is the EEG biofeedback making use for advanced analyses and second program is used to detection segment of stacionarity.
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Chin, Wai-yi, and 錢慧儀. "Linear maps preserving the spectrum?" Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B31225834.
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Webber, Matthew (Matthew William). "Mapping exoplanet clouds and albedo from phase curves and spectra." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/113795.
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Thesis: Ph. D. in Planetary Science, Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2017.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 89-91).
This thesis uses planetary albedo models to investigate variations in visible wavelength phase curves of exoplanets. We improve upon existing exoplanet giant planet albedo models and incorporate exoplanet general circulation models to analyze the composition and occurrence of clouds on tidally locked exoplanets. We confirm that non-uniform cloud coverage on the dayside of tidally locked exoplanets will affect the magnitude and location of the maximum of the phase curve. We then apply the models to the exoplanet Kepler-7b and consider the effect of varying cloud species, sedimentation efficiency, particle size, and cloud altitude. In the context of Kepler Space Telescope observations, we show that the cloud compositions and spatial distributions can be constrained. We also investigate exoplanet HD189733b, modeling its clouds, albedo and phase curves. We create 3D maps of cloud formation and analyze how cloud composition, spatial distribution, and temperature dependence affects albedo spectra for HD189733b. We use the modeled cloud patterns of spatially-varying composition and temperature to determine the observable albedo spectra and phase curves for HD189733b by fitting to the observations of Berdyugina et al. (2011), Evans el al. (2013), and Wiktorowicz et al. (2015). We show that these integrated albedo and general circulation models enable us to model non-uniform reflectivity due to exoplanet clouds, and to better interpret observations.
by Matthew Webber.
Ph. D. in Planetary Science
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Weigt, Martin. "Spectrum preserving linear mappings between Banach algebras." Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/53597.
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Thesis (MSc)--University of Stellenbosch, 2003.ENGLISH ABSTRACT: Let A and B be unital complex Banach algebras with identities 1 and I' respectively. A linear map T : A -+ B is invertibility preserving if Tx is invertible in B for every invertible x E A. We say that T is unital if Tl = I'. IfTx2 = (TX)2 for all x E A, we call T a Jordan homomorphism. We examine an unsolved problem posed by 1. Kaplansky: Let A and B be unital complex Banach algebras and T : A -+ B a unital invertibility preserving linear map. What conditions on A, Band T imply that T is a Jordan homomorphism? Partial motivation for this problem are the Gleason-Kahane-Zelazko Theorem (1968) and a result of Marcus and Purves (1959), these also being special instances of the problem. We will also look at other special cases answering Kaplansky's problem, the most important being the result stating that if A is a von Neumann algebra, B a semi-simple Banach algebra and T : A -+ B a unital bijective invertibility preserving linear map, then T is a Jordan homomorphism (B. Aupetit, 2000). For a unital complex Banach algebra A, we denote the spectrum of x E A by Sp (x, A). Let a(x, A) denote the union of Sp (x, A) and the bounded components of
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Fourie, Marilize. "Tissue Parameter Mapping in Children with Fetal Alcohol Spectrum Disorders." Master's thesis, Faculty of Health Sciences, 2020. http://hdl.handle.net/11427/32252.
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Background: Fetal alcohol spectrum disorders (FASD), which are caused by prenatal alcohol exposure (PAE), affects people around the world. Certain communities in South Africa have among the highest reported incidences of fetal alcohol syndrome (FAS) in the world. Although PAE-related brain alterations have been widely documented, the mechanisms whereby alcohol affects the brain are not clearly understood. MRI relaxation parameters T1, T2, T2* and proton density (PD), are basic tissue properties that reflect the underlying biology. The present study aims to advance our understanding of how PAE alters the microstructural properties of tissue by examining PAE-related changes in these tissue parameters in adolescents with FASD. Methods: The final sample used in this study consisted of 53 children from a previously studied longitudinal cohort (Jacobson et al., 2008) and 12 additionally recruited subjects. Of the 65 participants, 18 were diagnosed with FAS or partial FAS (PFAS) and made up the FAS/PFAS group, 18 were diagnosed as heavily exposed non-syndromal (HE) and 29 were age matched controls. Subjects were scanned at the Cape Universities Body Imaging Centre (CUBIC) located at Groote Schuur Hospital on a 3T Siemens Skyra MRI. Structural images were obtained using the MEMPRAGE sequence. From these images T1, T2, T2* and PD parameter maps were constructed and segmented into 43 regions of interest (ROI) using Freesurfer, FSL and AFNI. Linear regression analyses were used to analyse group differences as well as correlations between parameter values and the amount of alcohol the mother consumed during pregnancy. Results: Significant T1 differences were found in the caudate, cerebellar cortex, hippocampus, accumbens, putamen, choroid plexus, ventral diencephalon (DC), right vessel and ventricles. Significant T2 differences were found in the caudate, brain stem, corpus callosum (CC), amygdala, cerebral cortex, choroid plexus, vessels and ventricles. Significant T2* differences were found in the cerebellar cortex, optic chiasm and ventricles. Significant PD differences were found in the hippocampus and left lateral ventricle. The exploratory nature of this study resulted in none of the results surviving FDR correction for multiple comparisons. Conclusions: Overall, our findings point to regional PAE-related increases in water content and cellular and molecular changes in underlying tissue of the anatomical structure. Exceptions were the right cerebral cortex, brain stem, hippocampus, amygdala and ventral diencephalon where our findings point to less free water and increased cell density, and cerebellar cortex where simultaneous reductions in T1 and T2* suggest the possibility of increased iron content. In highly myelinated white matter structures, such as the CC and optic chiasm, our results point to PAErelated demyelination, and possibly increased iron. These findings extend previous knowledge of effects of PAE and demonstrate that tissues are affected at a microstructural level.
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Miller, Kai Joshua. "Characteristic changes in electrocorticographic power spectra of the human brain /." Thesis, Connect to this title online; UW restricted, 2008. http://hdl.handle.net/1773/9725.
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Dhliwayo, Jabulani. "Stimulated Brillouin scattering for distributed temperature sensing." Thesis, University of Kent, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242858.
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Gudmundson, Erik. "Signal Processing for Spectroscopic Applications." Doctoral thesis, Uppsala universitet, Avdelningen för systemteknik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-120194.
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Spectroscopic techniques allow for studies of materials and organisms on the atomic and molecular level. Examples of such techniques are nuclear magnetic resonance (NMR) spectroscopy—one of the principal techniques to obtain physical, chemical, electronic and structural information about molecules—and magnetic resonance imaging (MRI)—an important medical imaging technique for, e.g., visualization of the internal structure of the human body. The less well-known spectroscopic technique of nuclear quadrupole resonance (NQR) is related to NMR and MRI but with the difference that no external magnetic field is needed. NQR has found applications in, e.g., detection of explosives and narcotics. The first part of this thesis is focused on detection and identification of solid and liquid explosives using both NQR and NMR data. Methods allowing for uncertainties in the assumed signal amplitudes are proposed, as well as methods for estimation of model parameters that allow for non-uniform sampling of the data. The second part treats two medical applications. Firstly, new, fast methods for parameter estimation in MRI data are presented. MRI can be used for, e.g., the diagnosis of anomalies in the skin or in the brain. The presented methods allow for a significant decrease in computational complexity without loss in performance. Secondly, the estimation of blood flow velo-city using medical ultrasound scanners is addressed. Information about anomalies in the blood flow dynamics is an important tool for the diagnosis of, for example, stenosis and atherosclerosis. The presented methods make no assumption on the sampling schemes, allowing for duplex mode transmissions where B-mode images are interleaved with the Doppler emissions.
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Liang, Jason (Jason G. ). "Mapping crossing myofiber populations with Diffusion Spectrum Imaging in simulated and microfabricated model tissues." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/32947.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005.Includes bibliographical references (leaves 33-36).
The ability to resolve complex myofiber populations is important for relating architectural structure with mechanical unction in muscular tissues. To address this issue, we sought to validate the capacity of Diffusion Spectrum Imaging (DSI), an MRI method for assessing molecular diffusion in a confined geometry, to determine fiber alignment in tissues whose myofibers are aligned at varying orientations. By this method, molecular displacement in a tissue can be determined by Fourier transforming the echo intensity against gradient strength at fixed gradient pulse spacing. The displacement profiles are visualized by graphing 3D isocontour icons for each voxel, with the isocontour shape and size representing the magnitude and direction of the constituting fiber populations. Validation of DSI was accomplished with two sets of experiments: We simulated diffusive motion and a DSI experiment within the constraints of crossing fibers, and determined that DSI accurately depicts arbitrary angular relationships between crossing fibers. We also used DSI to accurately resolve the geometry of aligned channels in poly(dimethylsiloxane) (PDMS) microfluidic phantoms.
by Jason Liang.
S.B.
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Ming, Zuheng. "Paramètres spectraux à LPC Paramètres Mapping : approches multi-linéaires et GMM (appliqué aux voyelles françaises)." Phd thesis, Université de Grenoble, 2013. http://tel.archives-ouvertes.fr/tel-00935286.
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Le langage parlé complété (LPC) est un système de communication visuel qui utilise des formes de main placés dans différentes positions près du visage, en combinaison avec le discours de la lecture labiale naturel, pour améliorer la perception de la parole à partir de l'entrée visuelle pour les personnes sourdes. Cependant l'un des défis importants est la question de la communication de la parole entre les personnes normo-entendant qui ne pratiquent pas LPC mais produisent discours acoustique et les personnes sourdes qui utilisent la lecture labiale complété par code LPC pour la perception de la parole sans audition résiduelle. Dans notre travail, nous appliquons la méthode de régression linéaire multiple (MLR) et modèle gaussien de mélange (GMM) approche pour mapper des paramètres spectraux acoustiques à la position de la main dans LPC et la forme de la lèvre d'accompagnement. Nous donc contribué à la mise au point d'un système de traduction automatique dans le cadre de la synthèse de la parole visuelle.Cela prouve que l'approche MLR est bonne pour l'estimation des paramètres pour les lèvres à partir des paramètres spectraux car il y a forte corrélation linéaire entre les paramètres des lèvres et des paramètres spectraux. Cependant, la performance de l'approche MLR pour estimer la position de la main est faible car il n'y a pas de relation entre les positions de la main et des paramètres spectraux. En introduisant un espace intermédiaire, il s'avère que la structure de topologie similaire est la clé de la MLR. Afin de libérer de la contrainte linéaire de l'approche MLR, nous appliquons la méthode de cartographie basée sur GMM qui possède à la fois les propriétés de classification et de régression. Les paramètres de GMM sont estimés par les méthodes de formation supervisées, non supervisées et semi- supervisés séparément dans la vue de la théorie de l'apprentissage de la machine. La méthode de formation supervisée montre une grande efficacité et une bonne robustesse. Le Minimum Mean Square Error (MMSE) et Maximum A Posteriori Probabilité (MAP) sont utilisés comme critères de régression séparément dans l'approche de la cartographie basée sur GMM. Cela prouve que l'approche MLR est un cas particulier de l'approche de GMM lorsque le nombre de gaussiennes est égal à un. Ainsi, l'approche de la cartographie sur GMM peut améliorer la performance significative en comparaison avec le MLR en augmentant le nombre de gaussiennes. Enfin, les différentes approches de cartographie utilisées dans ce travail sont comparées dans une transition continue. Il montre que l'approche sur GMM peut effectuer bien grâce à la propriété de classification lorsque les données source et cible n'a pas de " relation" comme dans le cas de l'estimation de la position de la main, et il peut également améliorer les performances par la propriété de régression local lorsque la source et les données cible a forte corrélation comme dans le cas du paramètre de lèvre estimation. En outre, une prédiction directe de la géométrie des lèvres comporte de l'image naturelle de la bouche région d'intérêt (ROI) sur la base de la 2D transformée en cosinus discrète (DCT) combinée à une analyse en composante principale (ACP) est proposé. Les résultats montrent la possibilité d'estimer les caractéristiques géométriques de la lèvre avec une bonne précision en utilisant un ensemble réduit de prédicteurs dérivés des coefficients DCT.
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Chisholm, Daniel J. "Use of Principle Component Analysis for the identification and mapping of phases from energy-dispersive x-ray spectra." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1999. http://handle.dtic.mil/100.2/ADA359572.
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Bradford, Matt. "Mapping clay alteration across the northern Goldstrike property using spectroscopy and remote sensing, Eureka County, Nevada." Bowling Green, Ohio : Bowling Green State University, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=bgsu1216923357.
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Crumrine, Daiquirie. "Eye-gaze profiles of children with autism spectrum disorders in relation to fast-mapping and visual search abilities." Diss., Wichita State University, 2012. http://hdl.handle.net/10057/6095.
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Children learn new words through a process termed fast-mapping, which involves pairing novel words and objects after minimal exposure (Carey & Bartlett, 1978). There have been studies conducted to understand the fast-mapping processes in children with typical development (TD); however, this phenomenon has received less attention for children with autism spectrum disorders (ASD). In addition, no studies were found that investigated the eye-gaze patterns and fast-mapping abilities of children with ASD and TD. Furthermore, research involving visual search tasks has suggested that children with ASD demonstrate superior visual search skills when compared to children with TD (O’Riordan, Plaisted, Driver, & Baron-Cohen, 2001). The purpose of this study was two-fold: (1) to compare the eye-gaze patterns of children with ASD and TD in relation to fast-mapping; and (2) to compare the visual search abilities of children with ASD and TD. Ten children diagnosed with ASD and twenty children with TD, ages 5-7 participated. Participants were matched on nonverbal intelligence and receptive vocabulary skills. The Tobii 1750 eye-tracking system was used to capture eye-tracking measures. Overall, the results of Study 1 revealed that children with ASD were able to fast-map novel images and text at a similar rate to children with TD, despite having fewer fixations and shorter total fixation duration on novel stimuli. Study 2 revealed that children with ASD had similar visual search patterns as compared to children with TD. Children with ASD demonstrated more errors when locating targets but exhibited similar reaction times compared to children with TD. In summary, it appears that for the participants in these studies, children with ASD had different eye-gaze patterns for fast-mapping tasks and similar visual search skills when compared to TD children.Thesis (Ph.D.)--Wichita State University, College of Health Professions, Dept. of Communication Sciences and Disorders