Relevant bibliographies by topics / Vector Aperture

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  1. Journal articles
  2. Dissertations / Theses
  3. Books
  4. Book chapters
  5. Conference papers

Academic literature on the topic 'Vector Aperture'

Author: Grafiati
Published: 4 June 2021
Last updated: 1 February 2022

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Journal articles on the topic "Vector Aperture"

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Perna, Antonio Di, Riccardo Lanari, and Gilda Schirinzi. "Vector implementation of synthetic aperture radar processing." European Transactions on Telecommunications 2, no. 6 (November 1991): 649–54. http://dx.doi.org/10.1002/ett.4460020608.

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Youngworth, K. S., and T. G. Brown. "Focusing of high numerical aperture cylindrical-vector beams." Optics Express 7, no. 2 (July 17, 2000): 77. http://dx.doi.org/10.1364/oe.7.000077.

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Stafeev, S. S., and V. V. Kotlyar. "Formation of an elongated region of energy backflow using ring apertures." Computer Optics 43, no. 2 (April 2019): 193–99. http://dx.doi.org/10.18287/2412-6179-2019-43-2-193-199.

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In this paper, we have investigated the focusing of a second-order cylindrical vector beam by using a high numerical aperture (NA) lens limited by a ring aperture using the Richards-Wolf formulae. It was shown that the range of negative on-axis projections of the Poynting vector could be increased by increasing the depth of focus through the use of a ring aperture. It was shown that when focusing light with a lens with NA = 0.95, the use of a ring aperture limiting the entrance pupil angle to 0.9 of maximum, allows the depth of the region of negative on-axis Poynting vector projections to be four times increased, with the region width remaining almost unchanged and varying from 0.357 to 0.352 of the incident wavelength. Notably, the magnitude of the reverse energy flow was found to be larger than the direct one by a factor of 2.5.
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Normatov, Alexander, Boris Spektor, and Joseph Shamir. "Analysis of Phase Distribution of Focused Light in High Numerical Aperture Systems." Key Engineering Materials 437 (May 2010): 616–20. http://dx.doi.org/10.4028/www.scientific.net/kem.437.616.

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High numerical aperture focusing is becoming increasingly important for nanotechnology related applications. Rigorous, vector evaluation of the focused field, in such cases, is usually performed using the Richards-Wolf method which is based on the Debye approach. The resulting field is known to have a piecewise quasi planar phase. A corresponding result, produced by a Fresnel-Kirchhoff integral for aplanatic optical systems of medium and low numerical apertures, leads to the well known physical fact that a quadratic phase exists when the entrance pupil is not located at the front focal plane. Yet, the amplitudes produced in both ways are in a good agreement. In this work we investigated the difference, presented above, in a 2D system with the help of the Stratton-Chu diffraction integral. The amplitude obtained by the Stratton-Chu integral was quite similar to the classic results while the phase exhibited a quadratic behavior, with the quadratic coefficient depending on the numerical aperture of the optical system. For lower numerical apertures it approached the result obtained by the Fresnel-Kirchhoff integral while for higher numerical apertures it was approaching the Richards-Wolf result. A mathematical expression for the quadratic coefficient was derived and verified for various values of numerical aperture.
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Hayek, S. I., and T. W. Luce. "Aperture Effects in Planar Nearfield Acoustical Imaging." Journal of Vibration and Acoustics 110, no. 1 (January 1, 1988): 91–96. http://dx.doi.org/10.1115/1.3269486.

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The influence of the size of the measurement aperture on the accuracy of reconstruction of the pressure and vector velocity fields using underwater nearfield acoustical holography technique is examined. In this measurement technique, the amplitude and phase of the pressure in the nearfield of a planar structure submerged in water is measured at a set of points on a planar surface which constitute the measurement aperture. The reconstruction of the pressure and velocity vector fields on the surface of a vibrating submerged steel plate was found to be insensitive to the aperture size down to the size of the structure. Examples of aperture sizes ranging from six (6) times down to 1/2 of the size vibrating steel plate are shown. Thus, the total length of time spent on measurements underwater can be drastically reduced.
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Berriaud, C., G. Aubert, A. M. Bataille, P. Bredy, A. Dael, S. Klimko, P. Lavie, et al. "Development of an Innovative Wide Aperture Vector Magnet: WAVE." IEEE Transactions on Applied Superconductivity 26, no. 4 (June 2016): 1–4. http://dx.doi.org/10.1109/tasc.2016.2517338.

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Shun-Li Wang, Meng-Lin Li, and Pai-Chi Li. "Estimating the blood velocity vector using aperture domain data." IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control 54, no. 1 (January 2007): 70–78. http://dx.doi.org/10.1109/tuffc.2007.212.

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Oddershede, Niels, and Jorgen Jensen. "Effects Influencing Focusing in Synthetic Aperture Vector Flow Imaging." IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control 54, no. 9 (September 2007): 1811–25. http://dx.doi.org/10.1109/tuffc.2007.465.

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Ndop, J., T. J. Kim, W. Grill, and M. Pluta. "Synthetic aperture imaging by scanning acoustic microscopy with vector contrast." Ultrasonics 38, no. 1-8 (March 2000): 166–70. http://dx.doi.org/10.1016/s0041-624x(99)00091-8.

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Zhu, Wenguo, and Weilong She. "Tightly focusing vector circular airy beam through a hard aperture." Optics Communications 334 (January 2015): 303–7. http://dx.doi.org/10.1016/j.optcom.2014.08.045.

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Dissertations / Theses on the topic "Vector Aperture"

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Ament, Craig A. "High numerical aperture axial and transverse beam shaping using diffractive optics." Honors in the Major Thesis, University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/1348.

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This item is only available in print in the UCF Libraries. If this is your Honors Thesis, you can help us make it available online for use by researchers around the world by following the instructions on the distribution consent form at http://library.ucf.edu/Systems/DigitalInitiatives/DigitalCollections/InternetDistributionConsentAgreementForm.pdf You may also contact the project coordinator, Kerri Bottorff, at kerri.bottorff@ucf.edu for more information.
Bachelors
Sciences
Physics
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Black, James Noel. "Development of a Support-Vector-Machine-based Supervised Learning Algorithm for Land Cover Classification Using Polarimetric SAR Imagery." Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/85391.

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Land cover classification using Synthetic Aperture Radar (SAR) data has been a topic of great interest in recent literature. Food commodities output prediction through crop identification, environmental monitoring, and forest regrowth tracking are some of the many problems that can be aided by land cover classification methods. The need for fast and automated classification methods is apparent in a variety of applications involving vast amounts of SAR data. One fundamental step in any supervised learning classification algorithm is the selection and/or extraction of features present in the dataset to be used for class discrimination. A popular method that has been proposed for feature extraction from polarimetric data is to decompose the data into the underlying scattering mechanisms. In this research, the Freeman and Durden scattering model is applied to ALOS PALSAR fully polarimetric data for feature extraction. Efficient methods for solving the complex system of equations present in the scattering model are developed and compared. Using the features from the Freeman and Durden work, the classification capability of the model is assessed on amazon rainforest land cover types using a supervised Support Vector Machine (SVM) classification algorithm. The quantity of land cover types that can be discriminated using the model is also determined. Additionally, the performance of the median as a robust estimator in noisy environments for multi-pixel windowing is also characterized.
Master of Science
Land type classification using Radar data has been a topic of great interest in recent literature. Food commodities output prediction through crop identification, environmental monitoring, and forest regrowth tracking are some of the many problems that can be aided by land cover classification methods. The need for fast and automated classification methods is apparent in a variety of applications involving vast amounts of Radar data. One fundamental step in any classification algorithm is the selection and/or extraction of discriminating features present in the dataset to be used for class discrimination. A popular method that has been proposed for feature extraction from polarized Radar data is to decompose the data into the underlying scatter components. In this research, a scattering model is applied to real world data for feature extraction. Efficient methods for solving the complex system of equations present in the scattering model are developed and compared. Using the features from the scattering model, the classification capability of the model is assessed on amazon rainforest land types using a Support Vector Machine (SVM) classification algorithm. The quantity of land cover types that can be discriminated using the model is also determined and compared using different estimators.
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Tsang, Kwok-hon. "Design of an aperture-domain imaging method and signal acquisition hardware for ultrasound-based vector flow estimation." Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B43572315.

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Yang, Yun-zhi, Shun-ji Huang, and Jian-guo Wang. "The Realization Analysis of SAR Raw Data With Block Adaptive Vector Quantization Algorithm." International Foundation for Telemetering, 2003. http://hdl.handle.net/10150/605596.

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International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada
In this paper, we discuss a Block Adaptive Vector Quantization(BAVQ) Algorithm for Synthetic Aperture Radar(SAR). And we discuss a realization method of BAVQ algorithm for SAR raw data compressing in digital signal processor. Using the algorithm and the digital signal processor, we have compressed the SIR_C/X_SAR data.
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Jo, Sseunhyeun. "The vector behavior of aberrations in high numerical aperture (0.9 < NA < 3.1) laser focusing systems." Diss., The University of Arizona, 2001. http://hdl.handle.net/10150/290467.

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This dissertation investigates vector behavior of aberrations for high numerical aperture optical systems using a solid immersion lens (SIL). In order to analyze the system, this dissertation introduces the illumination system transfer function (ISTF), which is a map in the space of the exit pupil that shows reflection and transmission properties of individual plane waves that are emitted from corresponding points in the exit pupil. A vector analysis using ISTF presents the role of propagating and evanescent energy in the SIL systems, where the boundary between the them is defined by total internal reflection. The behavior of third-order aberrations such as coma and astigmatism, are dramatically affected by polarization in high NA systems. The irradiance distribution exhibits significantly different characteristics, depending on how coma or astigmatism is aligned with the incident linear polarized light. Vector effects including diffraction, polarization, and aberration, are used to analyze tolerances along with a comparison to geometrical optics. Apodization in amplitude and phase of the angular spectrum is generated in high NA focusing systems due to the difference in vector transmission and reflection for each plane wave. The size of the incident gaussian beam is effectively reduced at the exit pupil by the amplitude apodization and causes a spot size increase in image space. The apodization in phase is called gap-induced aberration due to its dependence on the air gap. The gap-induced aberration does not come from lens surface imperfection, and it exhibits multiple orders of spherical aberration and astigmatism. The apodization in amplitude and phase is well characterized by separable supergaussian functions, where each function depends on the refractive index of the SIL n SIL and the air gap height h. The best defocus, based on characteristics of gap-induced aberration, is suggested to be a good compensator only for low nSIL and h. The system performance, as represented by Strehl ratio and spot width, is characterized as a function of nSIL and h before and after defocus. C vector formalism is developed based on the common-mode and different-mode transmission coefficients between p and s polarization. Experiments to confirm the apodization are summarized and compared with simulation.
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Tsang, Kwok-hon, and 曾國瀚. "Design of an aperture-domain imaging method and signal acquisition hardware for ultrasound-based vector flow estimation." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B43572315.

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Jabbour, Toufic. "DESIGN, ANALYSIS, AND OPTIMIZATION OF DIFFRACTIVE OPTICAL ELEMENTS UNDER HIGH NUMERICAL APERTURE FOCUSING." Doctoral diss., University of Central Florida, 2009. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2837.

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The demand for high optical resolution has brought researchers to explore the use of beam shaping diffractive optical elements (DOEs) for improving performance of high numerical aperture (NA) optical systems. DOEs can be designed to modulate the amplitude, phase and/or polarization of a laser beam such that it focuses into a targeted irradiance distribution, or point spread function (PSF). The focused PSF can be reshaped in both the transverse focal plane and along the optical axis. Optical lithography, microscopy and direct laser writing are but a few of the many applications in which a properly designed DOE can significantly improve optical performance of the system. Designing DOEs for use in high-NA applications is complicated by electric field depolarization that occurs with tight focusing. The linear polarization of off-axis rays is tilted upon refraction towards the focal point, generating additional transverse and longitudinal polarization components. These additional field components contribute significantly to the shape of the PSF under tight focusing and cannot be neglected as in scalar diffraction theory. The PSF can be modeled more rigorously using the electromagnetic diffraction integrals derived by Wolf, which account for the full vector character of the field. In this work, optimization algorithms based on vector diffraction theory were developed for designing DOEs that reshape the PSF of a 1.4-NA objective lens. The optimization techniques include simple exhaustive search, iterative optimization (Method of Generalized Projections), and evolutionary computation (Particle Swarm Optimization). DOE designs were obtained that can reshape either the transverse PSF or the irradiance distribution along the optical axis. In one example of transverse beam shaping, all polarization components were simultaneously reshaped so their vector addition generates a focused flat-top square irradiance pattern. Other designs were obtained that can be used to narrow the axial irradiance distribution, giving a focused beam that is superresolved relative to the diffraction limit. In addition to theory, experimental studies were undertaken that include (1) fabricating an axially superresolving DOE, (2) incorporating the DOE into the optical setup, (3) imaging the focused PSF, and (4) measuring aberrations in the objective lens to study how these affect performance of the DOE.
Ph.D.
Optics and Photonics
Optics and Photonics
Optics PhD
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Meyer, Rory George Vincent. "Classification of ocean vessels from low resolution satellite SAR images." Diss., University of Pretoria, 2005. http://hdl.handle.net/2263/66224.

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In the long term it is beneficial to a country's economy to exploit the maritime environment surrounding it responsibly. It is also beneficial to protect this environment from poaching and pollution. To achieve this the responsible parties of a country must have an awareness of what is transpiring in the maritime domain. Synthetic aperture radar can provide an image, regardless of weather or light conditions, of the ocean showing most vessels therein. To monitor the ocean, using synthetic aperture radar imagery, at the lowest cost would require large swath synthetic aperture radar imagery. There exists a trade-off between large swath imagery and the image's resolution resulting in the largest swath image having the poorest resolution. Existing research has shown that it is possible to use coarse resolution synthetic aperture radar imagery to detect vessels at sea, but little work has been done on classifying those vessels. This research aims to investigate the coarse resolution classification information gap. This is done by using a dataset of matching synthetic aperture radar and ship transponder data to train a statistical classification algorithm in order to classify or estimate the length of vessels based on features extracted from their synthetic aperture radar image. The results of this research show that coarse resolution (approximately 40 m per pixel) synthetic aperture radar imagery is able to estimate vessel size for larger classes and provides insight on which vessel classes would require finer resolutions in order to be detected and classified reliably. The range of smaller vessel classes is usually limited to ports and fishing zones. These zones can be mapped using historical vessel transponder data and so a dedicated surveillance campaign can be optimised to use higher resolution products in these areas. The size estimation from the machine learning algorithm performs better than current techniques.
Dissertation (MEng)--University of Pretoria, 2017.
Electrical, Electronic and Computer Engineering
MEng
Unrestricted
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De, Gregorio Ludovica. "Development of new data fusion techniques for improving snow parameters estimation." Doctoral thesis, Università degli studi di Trento, 2019. http://hdl.handle.net/11572/245392.

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Water stored in snow is a critical contribution to the world’s available freshwater supply and is fundamental to the sustenance of natural ecosystems, agriculture and human societies. The importance of snow for the natural environment and for many socio-economic sectors in several mid‐ to high‐latitude mountain regions around the world, leads scientists to continuously develop new approaches to monitor and study snow and its properties. The need to develop new monitoring methods arises from the limitations of in situ measurements, which are pointwise, only possible in accessible and safe locations and do not allow for a continuous monitoring of the evolution of the snowpack and its characteristics. These limitations have been overcome by the increasingly used methods of remote monitoring with space-borne sensors that allow monitoring the wide spatial and temporal variability of the snowpack. Snow models, based on modeling the physical processes that occur in the snowpack, are an alternative to remote sensing for studying snow characteristics. However, from literature it is evident that both remote sensing and snow models suffer from limitations as well as have significant strengths that it would be worth jointly exploiting to achieve improved snow products. Accordingly, the main objective of this thesis is the development of novel methods for the estimation of snow parameters by exploiting the different properties of remote sensing and snow model data. In particular, the following specific novel contributions are presented in this thesis: i. A novel data fusion technique for improving the snow cover mapping. The proposed method is based on the exploitation of the snow cover maps derived from the AMUNDSEN snow model and the MODIS product together with their quality layer in a decision level fusion approach by mean of a machine learning technique, namely the Support Vector Machine (SVM). ii. A new approach has been developed for improving the snow water equivalent (SWE) product obtained from AMUNDSEN model simulations. The proposed method exploits some auxiliary information from optical remote sensing and from topographic characteristics of the study area in a new approach that differs from the classical data assimilation approaches and is based on the estimation of AMUNDSEN error with respect to the ground data through a k-NN algorithm. The new product has been validated with ground measurement data and by a comparison with MODIS snow cover maps. In a second step, the contribution of information derived from X-band SAR imagery acquired by COSMO-SkyMed constellation has been evaluated, by exploiting simulations from a theoretical model to enlarge the dataset.
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Costa, Jorge Alberto Lopes da. "Avaliação de dados de radar do sensor SAR-R99B no mapeamento do uso e cobertura da terra na Amazônia Central, município de Manaus, AM." Universidade Federal do Amazonas, 2011. http://tede.ufam.edu.br/handle/tede/4514.

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In recent decades the areas of rainforest in the Amazon region has been heavily impacted by a rapid process of conversion of vegetation cover in other types of use due to human action. In the context of global change, the use of mapping and monitoring land cover and provide information for the analysis and evaluation of environmental impacts due to accelerated changes in the landscape. Therefore, this study evaluated the potential of data from synthetic aperture radar for discriminating use and land cover in the region of Manaus, Amazonas state. We used a multipolarized image from sensor airborne SAR-R99B (L band), with 3 m spatial resolution. Were evaluated the MAXVER-ICM and SVM (Support Vector Machine) classifiers, where in all cases we used the images individually multipolarized amplitude (HH, HV and VV), in pairs (HH and HV), (HV and VV) and (HH and VV) and together (HH, HV and VV). The results were compared using as parameter the Kappa coefficient. The SVM classifier had higher accuracy compared to MAXVER-ICM classifier. The best classifications were obtained for the dual polarization (HH and VV) with MARVER-ICM classifier and (HH, HV and VV) with the SVM classifier both using the images with the filter. The accuracy was highest with SVM for classification and filter images (kappa = 0.7736). Were analyzed the influence of using GAMMA filter performance on the classifiers where it showed that filtered images have provided an increase in the results, on average, about 8%. Thus there was the analysis of the classification results, which found that the best result was provided by the dataset multipolarized (HH, HV and VV) classified by the SVM method. Thus, we concluded that the use of radar imagery in mapping thematic classes use and land cover in tropical regions, can be considered as a viable proposal.
Nas últimas décadas as áreas de floresta tropical na região Amazônica têm sido fortemente impactada por um rápido processo de conversão da cobertura vegetal em outros tipos de uso devido à ação antrópica. No contexto das mudanças globais, os mapeamentos e monitoramentos de uso e cobertura da terra fornecem subsídios para as análises e avaliações dos impactos ambientas em virtude de acelerados processos de mudança na paisagem. Neste contexto, este estudo avaliou o potencial dos dados de radar de abertura sintética para discriminação de uso e cobertura da terra na região de Manaus, estado do Amazonas. Foi utilizada uma imagem multipolarizada do sensor aerotransportado SAR-R99B (banda L), com 3 metros de resolução espacial. Realizaram-se classificações na imagem radar sem filtro e com filtro Gamma 3x3. Avaliou-se o classificador pontual MAXVER-ICM e o SVM (Support Vector Machine), onde em todos os casos utilizou-se das imagens multipolarizadas em amplitude individualmente (HH, HV e VV), aos pares (HH e HV), (HV e VV) e (HH e VV) e em conjunto (HH, HV e VV). Os resultados obtidos foram comparados utilizando-se como parâmetro o coeficiente de concordância Kappa. O classificador SVM apresentou acurácia superior em relação ao classificador MAXVER-ICM. As melhores classificações foram obtidas para a polarização dual HH e VV com o classificador MAXVER-ICM e (HH, HV e VV) com o classificador SVM ambos utilizando as imagens com filtro. A acurácia mais elevada foi para a classificação com SVM e imagens com filtro (kappa = 0,7736). Analisou-se a influência do uso de filtro GAMMA no desempenho dos classificadores onde se contatou que as imagens filtradas proporcionaram um incremento nos resultados, em média, na ordem de 8%. Deste modo realizou-se a análise dos resultados das classificações, onde se constatou que o melhor resultado foi proporcionado pelo conjunto de dados multipolarizados (HH, HV e VV)classificados através do método SVM. Assim, concluiu-se que o uso de imagens de radar no mapeamento de classes temáticas de uso e cobertura da terra, em regiões tropicais, pode ser considerado como uma proposta viável.
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Books on the topic "Vector Aperture"

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Jara Orellana,, Claudia. Efectos de la proteína Tau sobre la disfunción mitocondrial y el deterioro cognitivo en el envejecimiento. Universidad Autónoma de Chile, 2018. http://dx.doi.org/10.32457/20.500.12728/87452018dcbm6.

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El envejecimiento es un proceso complejo e irreversible que afecta el funcionamiento del cerebro y se considera el principal factor de riesgo para las patologías neurodegenerativas. Las mitocondrias son organelos fundamentales para la generación de energía, el equilibrio oxidativo y la regulación del calcio. Actualmente, se considera a la disfunción mitocondrial como un factor importante que contribuye al envejecimiento cerebral y a la patogénesis de diversas enfermedades neurodegenerativas. Este daño mitocondrial se ve reflejado en una disminución del metabolismo cerebral, aumentando el daño oxidativo y disminuyendo la formación de ATP. Estos daños alteran el normal funcionamiento neuronal y juegan un papel importante en la pérdida de la función cognitiva. Durante el envejecimiento, una serie de agregados proteicos se acumulan regularmente en el cerebro, como por ejemplo la proteína tau. Interesantemente, investigaciones de nuestro grupo y otros han determinado que bajo condiciones patológicas tau puede afectar la función sináptica debido a su capacidad para facilitar la falla mitocondrial. Dentro de este contexto, nuestro grupo recientemente ha encontrado que la ausencia de la proteína tau mejora la salud mitocondrial y las capacidades cognitivas en ratones jóvenes. Ya que las modificaciones patológicas de tau pueden afectar la función mitocondrial y la falla mitocondrial contribuye al envejecimiento cerebral, es interesante poder estudiar los efectos que la ausencia de tau podría tener sobre la función mitocondrial y las habilidades cognitivas durante el envejecimiento. En el desarrollo de esta tesis, observamos que la ausencia de tau previene la disfunción mitocondrial y el deterioro cognitivo asociado al envejecimiento. Se realizaron pruebas cognitivas, bioquímicas e histológicas utilizando ratones Wild Type (WT) y Knockout para la proteína tau (tau-/-) de 18 meses de edad. Nuestros resultados indican que la ausencia de tau previene la pérdida de la función cognitiva durante el envejecimiento, incluido la memoria de reconocimiento, la memoria espacial y las capacidades sociales. Además, los ratones tau-/- mostraron una mejor bioenergética mitocondrial, que fue evidenciada por una mayor producción de ATP y una menor sensibilidad a la sobrecarga de calcio en mitocondrias aisladas. También observamos elevados niveles de proteína ciclofilina-D(CypD) en el cerebro de ratones WT; de manera interesante, los ratones tau-/- envejecidos mostraron una disminución significativa de esta proteína en comparación con los ratones WT. CypD es una proteína fundamental en la formación del poro de transición de permeabilidad mitocondrial (mPTP). Para determinar si la disminución de CypD jugó un papel en la bioenergética mitocondrial mejorada de ratones tau-/- envejecidos, se realizó la sobreexpresión de CypD en el hipocampo de estos ratones utilizando la técnica de inyección estereotáxica de vectores lentivirales que codifican para CypD. Tres semanas después de la infección hipocampal, se realizaron pruebas conductuales y, posteriormente, se utilizó el hipocampo para evaluar la función mitocondrial. En estos estudios observamos que la expresión de CypD en ratones tau -/- redujo la producción de ATP y afecto la regulación del calcio produciendo un aumento de la sensibilidad al calcio mitocondrial, lo que sugiere apertura del mPTP. Más interesante es que los ratones tau-/- envejecidos infectados con lentivirus CypD mostraron una disminución significativa en sus capacidades cognitivas en comparación con los ratones tau-/- no infectados. En conclusión, nuestros resultados sugieren que la ausencia de tau previene la pérdida de habilidades cognitivas a través de la mejora de la función mitocondrial durante el envejecimiento. Estos efectos beneficiosos implican la regulación de la expresión de CypD y posiblemente la formación de mPTP. Esto también propone un nuevo y potencial objetivo terapéutico para prevenir alteraciones relacionadas con la edad.
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Book chapters on the topic "Vector Aperture"

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Khan, Saba N., S. Deepa, and P. Senthilkumaran. "Experimental Demonstration of Diffraction of Vector Field Singularities Through Diamond Shaped Aperture." In Springer Proceedings in Physics, 81–84. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-15-9259-1_18.

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Yagi, S., A. Sanuga, K. Tamura, and M. Sato. "Evaluation of Tissue Motion Vector Measurement System Utilizing Synthetic-Aperture Array Signal Processing for Real-Time Elastography." In Acoustical Imaging, 45–50. Dordrecht: Springer Netherlands, 2008. http://dx.doi.org/10.1007/978-1-4020-8823-0_7.

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Grossberg, Stephen. "Target Tracking, Navigation, and Decision-Making." In Conscious Mind, Resonant Brain, 337–52. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780190070557.003.0009.

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This chapter explains why and how tracking of objects moving relative to an observer, and visual optic flow navigation of an observer relative to the world, are controlled by complementary cortical streams through MT--MSTv and MT+-MSTd, respectively. Target tracking uses subtractive processing of visual signals to extract an object’s bounding contours as they move relative to a background. Navigation by optic flow uses additive processing of an entire scene to derive properties such as an observer’s heading, or self-motion direction, as it moves through the scene. The chapter explains how the aperture problem for computing heading in natural scenes is solved in MT+-MSTd using a hierarchy of processing stages that is homologous to the one that solves the aperture problem for computing motion direction in MT--MSTv. Both use feedback which obeys the ART Matching Rule to select final perceptual representations and choices. Compensation for eye movements using corollary discharge, or efference copy, signals enables an accurate heading direction to be computed. Neurophysiological data about heading direction are quantitatively simulated. Log polar processing by the cortical magnification factor simplifies computation of motion direction. This space-variant processing is maximally position invariant due to the cortical choice of network parameters. How smooth pursuit occurs, and is maintained during accurate tracking, is explained. Goal approach and obstacle avoidance are explained by attractor-repeller networks. Gaussian peak shifts control steering to a goal, as well as peak shift and behavioral contrast during operant conditioning, and vector decomposition during the relative motion of object parts.
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Priya, Ebenezer, and Srinivasan Subramanian. "Automated Method of Analysing Sputum Smear Tuberculosis Images Using Multifractal Approach." In Biomedical Signal and Image Processing in Patient Care, 184–215. IGI Global, 2018. http://dx.doi.org/10.4018/978-1-5225-2829-6.ch010.

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In this chapter, an attempt has been made to automate the analysis of positive and negative Tuberculosis (TB) sputum smear images using multifractal approach. The smear images (N=100) recorded under standard image acquisition protocol are considered. The images are subjected to multifractal analysis and the corresponding spectrum parameters are extracted. Most significant parameters are selected based on the principal component analysis. Further, these parameters are subjected to classification using support vector machine classifier with different kernels. Results demonstrate that the multifractal analysis is capable of discriminating positive and negative TB images. The values of apex, broadness and aperture of the singularity spectrum are higher for TB positive than negative images and are statistically significant. The performance estimators obtained in the classification process show that the polynomial kernel performs better. It appears that this method of texture analysis could be useful for automated analysis of TB using digital sputum smear images.
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Ben Abdallah, Wajih, and Riadh Abdelfattah. "3D InSAR Phase Unwrapping Within the Compressive Sensing Framework." In Environmental Information Systems, 809–41. IGI Global, 2019. http://dx.doi.org/10.4018/978-1-5225-7033-2.ch035.

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This chapter presents a new phase unwrapping algorithm for the 3D Interferometric Synthetic Aperture Radar (3D InSAR) volumes. The proposed approach is based on the relationship between the gradient vectors of the observed wrapped phase and the true phase respectively, when the Itoh condition is satisfied. Since this relationship is violated by the residue pixels in the observed wrapped phase, a general problem formulation which takes into account the estimation error due to these residue values is proposed. This approach exploits the temporal inter correlation between the interferometric frames within a compressive sensing framework. The 3D discrete curvelet transform is used in order to ensure a suitable sparse representation of the phase volume. The performance of the proposed 3D phase unwrapping algorithm is tested on simulated and real SAR 3D datasets
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Ben Abdallah, Wajih, and Riadh Abdelfattah. "3D InSAR Phase Unwrapping within the Compressive Sensing Framework." In Advances in Geospatial Technologies, 125–57. IGI Global, 2017. http://dx.doi.org/10.4018/978-1-5225-0937-0.ch005.

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This chapter presents a new phase unwrapping algorithm for the 3D Interferometric Synthetic Aperture Radar (3D InSAR) volumes. The proposed approach is based on the relationship between the gradient vectors of the observed wrapped phase and the true phase respectively, when the Itoh condition is satisfied. Since this relationship is violated by the residue pixels in the observed wrapped phase, a general problem formulation which takes into account the estimation error due to these residue values is proposed. This approach exploits the temporal inter correlation between the interferometric frames within a compressive sensing framework. The 3D discrete curvelet transform is used in order to ensure a suitable sparse representation of the phase volume. The performance of the proposed 3D phase unwrapping algorithm is tested on simulated and real SAR 3D datasets
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Conference papers on the topic "Vector Aperture"

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Muhuri, Arnab, Avik Bhattacharya, Ryo Natsuaki, and Akira Hirose. "Glacier surface velocity estimation using stokes vector correlation." In 2015 IEEE 5th Asia-Pacific Conference on Synthetic Aperture Radar (APSAR). IEEE, 2015. http://dx.doi.org/10.1109/apsar.2015.7306281.

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Villagomez-Hoyos, Carlos A., Simon Holbek, Matthias Bo Stuart, and Jorgen Arendt Jensen. "High frame rate synthetic aperture 3D vector flow imaging." In 2016 IEEE International Ultrasonics Symposium (IUS). IEEE, 2016. http://dx.doi.org/10.1109/ultsym.2016.7728664.

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Villagomez Hoyos, Carlos A., Matthias Bo Stuart, and Jorgen Arendt Jensen. "Adaptive multi-lag for synthetic aperture vector flow imaging." In 2014 IEEE International Ultrasonics Symposium (IUS). IEEE, 2014. http://dx.doi.org/10.1109/ultsym.2014.0427.

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Oddershede, Niels, Kristoffer Lindskov Hansen, Michael Bachmann Nielsen, and Jørgen Arendt Jensen. "In vivo examples of synthetic aperture vector flow imaging." In Medical Imaging, edited by Stanislav Y. Emelianov and Stephen A. McAleavey. SPIE, 2007. http://dx.doi.org/10.1117/12.706467.

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Tao, Wu, Chen Xi, Ruang Xiangwei, and Niu Lei. "Study on SAR target recognition based on Support Vector Machine." In 2009 2nd Asian-Pacific Conference on Synthetic Aperture Radar (APSAR). IEEE, 2009. http://dx.doi.org/10.1109/apsar.2009.5374190.

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Wang Yang, Lu Jiaguo, and Zhang Changyao. "Algorithm of target classification based on target decomposition and support vector machine." In 2007 1st Asian and Pacific Conference on Synthetic Aperture Radar. IEEE, 2007. http://dx.doi.org/10.1109/apsar.2007.4418724.

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Ping, Han, Zhang Rui, Su Zhi-gang, and Wu Ren-biao. "An iterative segmentation algorithm of SAR image based on support vector machine." In 2009 2nd Asian-Pacific Conference on Synthetic Aperture Radar (APSAR). IEEE, 2009. http://dx.doi.org/10.1109/apsar.2009.5374113.

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Chen, Shuo, Chenggao Luo, Bin Deng, Yuliang Qin, Hongqiang Wang, and Zhaowen Zhuang. "BM3D vector approximate message passing for radar coded-aperture imaging." In 2017 Progress in Electromagnetics Research Symposium - Fall (PIERS - FALL). IEEE, 2017. http://dx.doi.org/10.1109/piers-fall.2017.8293472.

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Stanziola, Antonio, Thomas Robins, Kai Riemer, and Meng-Xing Tang. "A Deep Learning Approach to Synthetic Aperture Vector Flow Imaging." In 2018 IEEE International Ultrasonics Symposium (IUS). IEEE, 2018. http://dx.doi.org/10.1109/ultsym.2018.8580021.

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Burki, Jehanzeb, Touseef Ali, and Shahzad Arshad. "Vector network analyzer (VNA) based synthetic aperture radar (SAR) imaging." In 2013 16th International Multi Topic Conference (INMIC). IEEE, 2013. http://dx.doi.org/10.1109/inmic.2013.6731351.

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