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SOME RESULTS ON CONTROLLED Frames IN HILBERT SPACES

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Acta Mathematica Scientia 2016年第3期36卷 655-665页

作者： Kamran MUSAZADEH Hassan KHANDANI Department of Mathematics College of ScienceMahabad BranchIslamic Azad University

We use two appropriate bounded invertible operators to define a controlled frame with optimal frame bounds. We characterize those operators that produces Parseval controlled Frames also we state a way to construct nearly Parseval controlled Frames. We intro- duce a new perturbation of controlled Frames to obtain new Frames from a given one. Also we reduce the distance of Frames by appropriate operators and produce nearly dual Frames from two given Frames which are not dual Frames for each other.

关键词： Frames Parseval Frames dual Frames controlled Frames reconstruction formula perturbation

SOME PROPERTIES OF OPERATOR-VALUED Frames

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Acta Mathematica Scientia 2016年第2期36卷 469-476页

作者： Laura GAVRUTA Pasc GAVRUTA politehnica university of timisoara department of mathematicsVictoriei Square no.2300006 TimisoaraRomania

Operator-valued Frames （or g-Frames） are generalizations of Frames and fusion Frames and have been used in packets encoding, quantum computing, theory of coherent states and more. In this article, we give a new formula for operator-valued Frames for finite dimensional Hilbert spaces. As an application, we derive in a simple manner a recent result of A. Najati concerning the approximation of g-Frames by Parseval ones. We obtain also some results concerning the best approximation of operator-valued Frames by its alternate duals, with optimal estimates.

关键词： Frames g-Frames

Generalized Sampling in Shift Invariant Spaces with Frames

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Acta Mathematica Sinica,English Series 2012年第9期28卷 1823-1844页

作者： Stefan ERICSSON Department of Engineering Sciences and Mathematics Lule University of Technology

Generalized sampling in a shift invariant subspace V of L2（R） is considered. A function f in V is processed with different filters Lm and then one tries to reconstruct f from the samples L^mf（j＇k）. We develop a theory of how to do this in the case when V possesses a shift invariant frame. Special attention is paid to the question： How to obtain dual Frames with compact support？

关键词： Generalized sampling Frames Riesz basis reproducing kernel shift invariant spaces

Tetrapartite entanglement measures of W-class in noninertial Frames

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Chinese Physics B 2019年第7期28卷 122-130页

作者： Ariadna J. Torres-Arenas Edgar O. Lopez-Zuniga J. Antonio Saldana-Herrera Qian Dong Guo-Hua Sun Shi-Hai Dong Laboratorio de Información Cuantica CIDETEC Instituto Politecnico Nacional UPALM CDMX 07700 Mexico Facultad de Ciencias Fisico Matematicas Universidad Autónoma de Nuevo Leon San Nicolas de los Garza NL 66450 Mexico Catedratica CONACyT Centro de Investigacion en Computacion Instituto Politecnico Nacional UPALM CDMX 07738 Mexico

We present the entanglement measures of a tetrapartite W-class entangled system in a noninertial frame, where the transformation between Minkowski and Rindler coordinates is applied.Two cases are considered.First, when one qubit has uniform acceleration whilst the other three remain stationary.Second, when two qubits have nonuniform accelerations and the others stay inertial.The 1–1 tangle, 1–3 tangle, and whole entanglement measurements π4 and Π4, are studied and illustrated with graphics through their dependence on the acceleration parameter rd for the first case and rc and rd for the second case.It is found that the negativities(1–1 tangle and 1–3 tangle) and π-tangle decrease when the acceleration parameter rd or in the second case rc and rd increase, remaining a nonzero entanglement in the majority of the results.This means that the system will be always entangled except for special cases.It is shown that only the 1–1 tangle for the first case vanishes at infinite accelerations, but for the second case the 1–1 tangle disappears completely when r > 0.472473.An analytical expression for the von Neumann information entropy of the system is found and we note that it increases with the acceleration parameter.

关键词： W-class tetrapartite entanglement Dirac field noninertial Frames nonuniform acceleration

Real-Time High-Resolution MRI Endoscopy at up to 10 Frames per Second

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Biomedical Engineering Frontiers 2021年第1期2卷 55-64页

作者： Xiaoyang Liu Parag Karmarkar Dirk Voit Jens Frahm Clifford R.Weiss Dara L.Kraitchman Paul A.Bottomley Department of Electrical and Computer Engineering Johns Hopkins UniversityUSA The Division of MR Research Department of RadiologyJohns Hopkins UniversityBaltimoreMarylandUSA Biomedizinishe NMR Max-Plank-Institut fur Biophysikalische ChemieGottingenGermany The Division of Interventional Radiology Department of RadiologyJohns Hopkins UniversityBaltimoreMarylandUSA

Objective.Atherosclerosis is a leading cause of mortality and morbidity.Optical endoscopy,ultrasound,and X-ray offer minimally invasive imaging assessments but have limited sensitivity for characterizing disease and therapeutic response.Magnetic resonance imaging(MRI)endoscopy is a newer idea employing tiny catheter-mounted detectors connected to the MRI scanner.It can see through vessel walls and provide soft-tissue sensitivity,but its slow imaging speed limits practical applications.Our goal is highresolution MRI endoscopy with real-time imaging speeds comparable to existing modalities.Methods.Intravascular(3 mm)transmit-receive MRI endoscopes were fabricated for highly undersampled radial-projection MRI in a clinical 3-tesla MRI scanner.Iterative nonlinear reconstruction was accelerated using graphics processor units connected via a single ethernet cable to achieve true real-time endoscopy visualization at the scanner.MRI endoscopy was performed at 6-10 Frames/sec and 200-300μm resolution in human arterial specimens and porcine vessels ex vivo and in vivo and compared with fully sampled 0.3 Frames/sec and three-dimensional reference scans using mutual information(MI)and structural similarity(3-SSIM)indices.Results.High-speed MRI endoscopy at 6-10 Frames/sec was consistent with fully sampled MRI endoscopy and histology,with feasibility demonstrated in vivo in a large animal model.A 20-30-fold speed-up vs.0.3 Frames/sec reference scans came at a cost of~7%in MI and~45%in 3-SSIM,with reduced motion sensitivity.Conclusion.High-resolution MRI endoscopy can now be performed at frame rates comparable to those of X-ray and optical endoscopy and could provide an alternative to existing modalities,with MRI’s advantages of soft-tissue sensitivity and lack of ionizing radiation.

关键词： scanner Frames mounted

The asymptotic existence of Frames with a pair of orthogonal frame resolutions

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Science China Mathematics 2019年第9期62卷 1839-1850页

作者： Changyuan Wang Yanxun Chang Tao Feng Department of Mathematics Beijing Jiaotong UniversityBeijing100044China School of Mathematics and Statistics Zaozhuang UniversityZaozhuang277160China

Motivated by the applications to generalized Howell designs and multiply constant-weight codes, we establish an asymptotic existence theorem for(k, λ)-Frames of type g^n with a pair of orthogonal frame resolutions vi... 详细信息

关键词： Frames orthogonal frame resolutions asymptotic existence generalized Howell designs multiply constant-weight codes

Asymptotic Boundary Forms for Tight Gabor Frames and Lattice Localization Domains

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Journal of Applied Mathematics and Physics 2015年第10期3卷 1316-1342页

作者： H. G. Feichtinger K. Nowak M. Pap Faculty of Mathematics University Vienna Wien Austria Department of Computer Science Drexel University Philadelphia PA USA Faculty of Sciences University of Pécs Pécs Hungary

We consider Gabor localization operators ?defined by two parameters, the generating function ?of a tight Gabor frame , indexed by a lattice , and a domain ?whose boundary consists of line segments connecting certain points of . We provide an explicit formula for the boundary form , the normalized limit of the projection functional , where ?are the eigenvalues of the localization operators ?applied to dilated domains , R is an integer and is the area of the fundamental domain. The boundary form expresses quantitatively the asymptotic interactions between the generating function ?and the oriented boundary ?from the point of view of the projection functional, which measures to what degree a given trace class operator fails to be an orthogonal projection. Keeping the area of the localization domain ?bounded above corresponds to controlling the relative dimensionality of the localization problem.

关键词： Toeplitz Operators Phase Space Localization Tight Gabor Frames Semi-Classical Limit

Get Frames;Set Agendas——Identifying Agenda-Setting as One Aspect of Framing

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Get Frames;Set Agendas——Identifying Agenda-Setting as One ...

平凡生活造梦者大名鼎鼎的24Frames和他们的爱情大片

中国传媒大学第七届全国新闻学与传播学博士生学术研讨会

作者：何太虚 COMMUNICATION UNIVERSITY OF CHINA

There is no doubt regarding the popularity and the usefulness of agenda-setting and Framing theories in the communication research field. Both theories explain the ways of presenting of selected issues to the audience(s) by communicators. Theorists in both camp share many concepts such as salience to formulate their respective conceptualizations. Allured by this commonness, scholars in the agenda-setting camp seek to accommodate framing theory also within their own quarters. This has caused an immense dispute between two camps and framing scholars see it as a colonization attempt of their research area. It is widely understood that the conceptualization problems in framing theory also cause a reason for the dispute. Hence, this paper starts with proving better definitions for the phenomena of Frames and the activity of framing. Later similarities and differences of two respective research instruments are compared and propose a way out of prevailing dispute. In this regard, broader nature of framing theory is elaborated. By doing so, agenda-setting theory is camped within that wide-ranging research area. It is expected that with this new identification, once adopted, it may serve better both camps to understand the communication process. In addition to that, in such a setting, the strength of agenda-setting theory could also be well comprehended.

关键词： Frames Framing agenda-setting research dispute

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人像摄影 2013年第12期 28-32页

作者：依晴

专业背景,创意头脑,精湛技艺,经验积累,令年轻的24Frames如同镶了金边一样地幻射出惊艳的光芒。知名度和美誉度一路飙升的同时,他们也成为同行们竞相模仿的典范。曾有人问,婚礼跟拍能做成微电影吗?通常的回答是:做不了,即使做了效果也... 详细信息

专业背景,创意头脑,精湛技艺,经验积累,令年轻的24Frames如同镶了金边一样地幻射出惊艳的光芒。知名度和美誉度一路飙升的同时,他们也成为同行们竞相模仿的典范。曾有人问,婚礼跟拍能做成微电影吗?通常的回答是:做不了,即使做了效果也不好。现在,24Frames做到了。他们打破传统的婚礼记录模式,融入情感和创意细节,让影像变得更加生动感人。他们的作品让新人骄傲地发出这样的感慨:婚礼最值得投资的就是摄影和摄像,因为它让一切美好都"瞬间即永恒"。蔡锦说,有些事,不是看到了希望才去坚持,而是因为坚持了才会看到希望。

关键词：平凡生活 Frames 造梦斯坦尼康生动感人拍摄手法创作思路品牌宣传中国传媒大学机缘巧合