The Experts below are selected from a list of 291 Experts worldwide ranked by ideXlab platform
Hernan Jara - One of the best experts on this subject based on the ideXlab platform.
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improved t2 mapping accuracy with dual Echo turbo spin Echo Effect of phase encoding profile orders
Magnetic Resonance in Medicine, 2013Co-Authors: Stephan W. Anderson, Osamu Sakai, Jorge A. Soto, Hernan JaraAbstract:Turbo spin Echo (TSE) pulse sequences have been applied to estimate T(2) relaxation times in clinically feasible scan times. However, T(2) estimations using TSE pulse sequences has been shown to differ considerable from reference standard sequences due to several sources of error. The purpose of this work was to apply voxel-sensitivity formalism to correct for one such source of error introduced by differing phase encoding profile orders with dual-Echo TSE pulse sequences. The American College of Radiology phantom and the brains of two healthy volunteers were imaged using dual-Echo TSE as well as 32-Echo spin-Echo acquisitions and T(2) estimations from uncorrected and voxel-sensitivity formalism-corrected dual-Echo TSE and 32-Echo acquisitions were compared. In all regions of the brain and the majority of the analyses of the American College of Radiology phantom, voxel-sensitivity formalism correction resulted in considerable improvements in dual-Echo TSE T(2) estimation compared with the 32-Echo acquisition, with improvements in T(2) value accuracy ranging from 5.2% to 18.6%.
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Improved T2 mapping accuracy with dual‐Echo turbo spin Echo: Effect of phase encoding profile orders
Magnetic resonance in medicine, 2012Co-Authors: Stephan W. Anderson, Osamu Sakai, Jorge A. Soto, Hernan JaraAbstract:Turbo spin Echo (TSE) pulse sequences have been applied to estimate T(2) relaxation times in clinically feasible scan times. However, T(2) estimations using TSE pulse sequences has been shown to differ considerable from reference standard sequences due to several sources of error. The purpose of this work was to apply voxel-sensitivity formalism to correct for one such source of error introduced by differing phase encoding profile orders with dual-Echo TSE pulse sequences. The American College of Radiology phantom and the brains of two healthy volunteers were imaged using dual-Echo TSE as well as 32-Echo spin-Echo acquisitions and T(2) estimations from uncorrected and voxel-sensitivity formalism-corrected dual-Echo TSE and 32-Echo acquisitions were compared. In all regions of the brain and the majority of the analyses of the American College of Radiology phantom, voxel-sensitivity formalism correction resulted in considerable improvements in dual-Echo TSE T(2) estimation compared with the 32-Echo acquisition, with improvements in T(2) value accuracy ranging from 5.2% to 18.6%.
E. A. Manykin - One of the best experts on this subject based on the ideXlab platform.
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Principles of construction of optical Echo processors
Soviet Journal of Quantum Electronics, 1991Co-Authors: E. A. Manykin, N A ChernyshevAbstract:An analysis is made of the possibility of utilization of the photon Echo Effect in optical digital processing of discrete images by the method of control operators, which makes it possible to solve a number of problems. Different regimes for the excitation of the photon Echo are in practice usable in all component parts of a processor, which makes this Effect potentially promising for the use in optical data processing.
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Optical implementation of neutral network models using the photon Echo Effect
Optics Communications, 1991Co-Authors: M. N. Belov, E. A. ManykinAbstract:Abstract The possibility of optical implementation of a neutral network using the photon Echo Effect is investigated theoretically. Optical architectures based on this Effect and advantages of the present approach are discussed.
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Optical associative memory based on an Echo correlator
Optics letters, 1991Co-Authors: M. N. Belov, E. A. ManykinAbstract:A physical principle of the associative-memory optical implementation by using the photon-Echo Effect is proposed. The properties inherent in this phenomenon permit an optical scheme similar to the nonlinear holographic associative memory [Appl. Opt. 26, 1900 (1987)] to be considered. The associative-memory system based on the photon-Echo Effect uses a temporal selectivity instead of a spatial one.
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Higher-order neural network and photon-Echo Effect
Neural Networks, 1991Co-Authors: E. A. Manykin, M. N. BelovAbstract:Abstract Properties of the photon-Echo Effect are theoretically investigated for implementation of higher-order neural networks. An optical scheme of the second-order neural network is proposed on this basis. The importance of an additional time coordinate inherent in the photon-Echo Effect is shown.
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Neural network architecture based on nonlinear interaction of ultrashort optical pulses with matter
Proceedings of 1993 International Conference on Neural Networks (IJCNN-93-Nagoya Japan), 1Co-Authors: E. A. ManykinAbstract:Properties of nonlinear optic Effect (photon Echo or time-domain four wave mixing) are suggested for implementation of neural network (NN) architecture especially for high-order NN. The different optical schemes of the second order NN are proposed on this basis. Optical architectures based on photon-Echo Effect and advantages of the present approach are discussed. The importance of an additional time coordinate inherent in photon-Echo Effect is shown. The associative memory system based on this nonlinear Effect uses a temporal selectivity instead of a spatial one. The dynamics of such NN is governed by the whole prehistory of the system, which provides means for an analysis of time sequences of images of any order of complexity.
Albert K. H. Kong - One of the best experts on this subject based on the ideXlab platform.
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X-Ray afterglow of SWIFT J1644+57: a Compton Echo?
The Astrophysical Journal, 2015Co-Authors: K. S. Cheng, Dmitrii Chernyshov, V. A. Dogiel, Albert K. H. KongAbstract:Swift, Chandra and XMM have found a weak but nearly constant X-ray component from Swift J1644+57 that appeared at ~500 days and was visible at least until ~ 1400 days after the stellar capture, which cannot be explained by standard tidal disruption theories. We suggest that this X-ray afterglow component may result from Thomson scattering between the primary X-rays and its surrounding plasma, i.e. the Compton Echo Effect. Similar phenomena has also been observed from molecular clouds in our Galactic Center, which were caused by the past activity of Srg A*. If this interpretation of Swift J1644+57 afterglow is correct, this is the first Compton Echo Effect observed in the cosmological distances.
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X-Ray Echo from SWIFT J1644+57: a Compton Echo?
arXiv: High Energy Astrophysical Phenomena, 2015Co-Authors: K. S. Cheng, Dmitrii Chernyshov, V. A. Dogiel, Albert K. H. KongAbstract:Swift, Chandra and XMM have found a weak but nearly constant X-ray component from Swift J1644+57 that appeared at $\sim$ 500 days and was visible at least until ~ 1400 days after the stellar capture, which cannot be explained by standard tidal disruption theories. We suggest that this X-ray afterglow component may result from Thomson scattering between the primary X-rays and its surrounding plasma, i.e. the Compton Echo Effect. Similar phenomena has also been observed from molecular clouds in our Galactic Center, which were caused by the past activity of Srg A*. If this interpretation of Swift J1644+57 afterglow is correct, this is the first Compton Echo Effect observed in the cosmological distances.
Stephan W. Anderson - One of the best experts on this subject based on the ideXlab platform.
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improved t2 mapping accuracy with dual Echo turbo spin Echo Effect of phase encoding profile orders
Magnetic Resonance in Medicine, 2013Co-Authors: Stephan W. Anderson, Osamu Sakai, Jorge A. Soto, Hernan JaraAbstract:Turbo spin Echo (TSE) pulse sequences have been applied to estimate T(2) relaxation times in clinically feasible scan times. However, T(2) estimations using TSE pulse sequences has been shown to differ considerable from reference standard sequences due to several sources of error. The purpose of this work was to apply voxel-sensitivity formalism to correct for one such source of error introduced by differing phase encoding profile orders with dual-Echo TSE pulse sequences. The American College of Radiology phantom and the brains of two healthy volunteers were imaged using dual-Echo TSE as well as 32-Echo spin-Echo acquisitions and T(2) estimations from uncorrected and voxel-sensitivity formalism-corrected dual-Echo TSE and 32-Echo acquisitions were compared. In all regions of the brain and the majority of the analyses of the American College of Radiology phantom, voxel-sensitivity formalism correction resulted in considerable improvements in dual-Echo TSE T(2) estimation compared with the 32-Echo acquisition, with improvements in T(2) value accuracy ranging from 5.2% to 18.6%.
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Improved T2 mapping accuracy with dual‐Echo turbo spin Echo: Effect of phase encoding profile orders
Magnetic resonance in medicine, 2012Co-Authors: Stephan W. Anderson, Osamu Sakai, Jorge A. Soto, Hernan JaraAbstract:Turbo spin Echo (TSE) pulse sequences have been applied to estimate T(2) relaxation times in clinically feasible scan times. However, T(2) estimations using TSE pulse sequences has been shown to differ considerable from reference standard sequences due to several sources of error. The purpose of this work was to apply voxel-sensitivity formalism to correct for one such source of error introduced by differing phase encoding profile orders with dual-Echo TSE pulse sequences. The American College of Radiology phantom and the brains of two healthy volunteers were imaged using dual-Echo TSE as well as 32-Echo spin-Echo acquisitions and T(2) estimations from uncorrected and voxel-sensitivity formalism-corrected dual-Echo TSE and 32-Echo acquisitions were compared. In all regions of the brain and the majority of the analyses of the American College of Radiology phantom, voxel-sensitivity formalism correction resulted in considerable improvements in dual-Echo TSE T(2) estimation compared with the 32-Echo acquisition, with improvements in T(2) value accuracy ranging from 5.2% to 18.6%.
M. N. Belov - One of the best experts on this subject based on the ideXlab platform.
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Optical implementation of neutral network models using the photon Echo Effect
Optics Communications, 1991Co-Authors: M. N. Belov, E. A. ManykinAbstract:Abstract The possibility of optical implementation of a neutral network using the photon Echo Effect is investigated theoretically. Optical architectures based on this Effect and advantages of the present approach are discussed.
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Optical associative memory based on an Echo correlator
Optics letters, 1991Co-Authors: M. N. Belov, E. A. ManykinAbstract:A physical principle of the associative-memory optical implementation by using the photon-Echo Effect is proposed. The properties inherent in this phenomenon permit an optical scheme similar to the nonlinear holographic associative memory [Appl. Opt. 26, 1900 (1987)] to be considered. The associative-memory system based on the photon-Echo Effect uses a temporal selectivity instead of a spatial one.
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Higher-order neural network and photon-Echo Effect
Neural Networks, 1991Co-Authors: E. A. Manykin, M. N. BelovAbstract:Abstract Properties of the photon-Echo Effect are theoretically investigated for implementation of higher-order neural networks. An optical scheme of the second-order neural network is proposed on this basis. The importance of an additional time coordinate inherent in the photon-Echo Effect is shown.
