Gabor frames can advantageously be redefined using the Heisenberg-Weyl operators familiar from harmonic analysis and quantum mechanics. Not only does this redefinition allow us to recover in a very simple way known results of symplectic covariance, but it immediately leads to the consideration of a general deformation scheme by Hamiltonian isotopies ( arbitrary paths of non-linear symplectic mappings passing through the identity). We will study in some detail an associated weak notion of Hamiltonian deformation of Gabor frames, using ideas from semiclassical physics involving coherent states and Gaussian approximations. We will thereafter discuss possible applications and extensions of our method, which can be viewed - as the title suggests - as the very first steps towards a general deformation theory for Gabor frames.
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http://dx.doi.org/10.1016/j.acha.2014.03.010 | DOI Listing |
J Neural Eng
December 2024
Timeflux, Paris, France.
Reactive brain-computer interfaces typically rely on repetitive visual stimuli, which can strain the eyes and cause attentional distraction. To address these challenges, we propose a novel approach rooted in visual neuroscience to design visual Stimuli for Augmented Response (StAR). The StAR stimuli consist of small randomly-orientedorpatches that optimize foveal neural response while reducing peripheral distraction.
View Article and Find Full Text PDFSci Rep
July 2024
School of Civil Engineering, Chongqing University, Chongqing, 400045, China.
A method based on Gabor spectral mode transmissibility functions (GSMTFs) is proposed to detect local damage in a cantilevered structure under nonstationary ambient excitations. Gabor transformation and singular value decomposition are used to reduce the influences of other vibration modes on Gabor spectral mode transmissibility functions and process nonstationary structural responses, respectively. A new state characteristic based on the fundamental structure frequency is formulated on the basis of the GSMTFs, eventually leading to the development of a new damage indicator.
View Article and Find Full Text PDFJ Opt Soc Am A Opt Image Sci Vis
September 2023
In wafer metrology, the knowledge of the photomask together with the deposition process only reveals the approximate geometry and material properties of the structures on a wafer as a priori information. With this prior information and a parametrized description of the scatterers, we demonstrate the performance of the Gauss-Newton method for the precise and noise-robust reconstruction of the actual structures, without further regularization of the inverse problem. The structures are modeled as 3D finite dielectric scatterers with a uniform polygonal cross-section along their height, embedded in a planarly layered medium.
View Article and Find Full Text PDFPathol Oncol Res
June 2023
Department of Clinical Neuropathology, King's College Hospital, London, United Kingdom.
Angiocentric gliomas (AG) in brainstem location are exceedingly rare and might cause differential diagnostic problems and uncertainty regarding the best therapeutic approach. Hereby, we describe the clinicopathological findings in a brainstem AG presenting in a toddler child and review the literature. A 2-year-old boy presented with 5 weeks history of gait disturbances, frequent falls, left-sided torticollis and swallowing problems.
View Article and Find Full Text PDFPhys Eng Sci Med
June 2022
Electrical and Electronic Engineering, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 32610, Perak, Malaysia.
Decoding asynchronous electroencephalogram (A-EEG) signals is a crucial challenge in the emerging field of EEG based brain-computer interface. In the case of A-EEG signals, the time markers of motor activity are absent. The paper proposes a method to decompose the A-EEG signals using gabor elementary function designed with Gabor frames.
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