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6,629
Sparse MRI: The Application of Compressed Sensing for Rapid MR Imaging
- MAGNETIC RESONANCE IN MEDICINE 58:1182–1195
, 2007
"... The sparsity which is implicit in MR images is exploited to significantly undersample k-space. Some MR images such as angiograms are already sparse in the pixel representation; other, more complicated images have a sparse representation in some transform domain–for example, in terms of spatial finit ..."
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Cited by 538 (11 self)
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undersampling schemes are developed and analyzed by means of their aliasing interference. Incoherence is introduced by pseudo-random variable-density undersampling of phase-encodes. The reconstruction is performed by minimizing the ℓ1 norm of a transformed image, subject to data fidelity constraints. Examples
Controller Synthesis with Guaranteed Closed-Loop Phase Constraints
"... Abstract — In this paper, we present an analysis and synthesis framework for guaranteeing that the phase of a single-input, single-output closed-loop transfer function is contained in the interval [−α, α] for a given α>0 at all frequencies. Specifically, we first derive a sufficient condition inv ..."
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involving a frequency domain inequality for guaranteeing a given phase constraint. Next, we use the Kalman-Yakubovich-Popov theorem to derive an equivalent time domain condition. In the case where α = π 2, we show that frequency and time domain sufficient conditions specialize to the positivity theorem
On Question about Extension of Maximin Problem with Phase Constraints
"... Copyright c © 2013 Artem Baklanov. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. We study the asymptotic behavior of maximin values ..."
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values of a payoff function, when relaxed constraints are tightened. The payoff function depends on the trajectories of controlled systems of the first and second player. An extension in the class of the Radon measures is used. The asymptotic equivalence between two types of the constraints relaxations
Research Article Linear Discrete Pursuit Game with Phase Constraints
"... Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. We consider a linear pursuit game of one pursuer and one evader whose motions are described by different-type linear discrete systems. Position of the evad ..."
Variable Digital Filter With Group Delay Flatness Specification or Phase Constraints
"... Abstract—In this paper, we consider the design of finite-im-pulse response variable digital filters (VDFs) with variable cutoff frequency or variable fractional delay. We propose the design of VDFs with minimum integral squared error and constraints on the maximum error deviation in conjunction with ..."
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with flatness group delay specification or phase constraints. These specifications allow the VDFs to have approximately linear phase, especially in the passband. As these specifications are required to be satisfied for all the filters generated by the VDF with controllable spectral characteristics, the linear
Linear Pursuit Differential Game under Phase Constraint on the State of Evader
"... We consider a linear pursuit differential game of one pursuer and one evader. Controls of the pursuer and evader are subjected to integral and geometric constraints, respectively. In addition, phase constraint is imposed on the state of evader, whereas pursuer moves throughout the space. We say tha ..."
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We consider a linear pursuit differential game of one pursuer and one evader. Controls of the pursuer and evader are subjected to integral and geometric constraints, respectively. In addition, phase constraint is imposed on the state of evader, whereas pursuer moves throughout the space. We say
Phase retrieval algorithms: a comparison
- Appl. Opt
, 1982
"... Iterative algorithms for phase retrieval from intensity data are compared to gradient search methods. Both the problem of phase retrieval from two intensity measurements (in electron microscopy or wave front sens-ing) and the problem of phase retrieval from a single intensity measurement plus a non- ..."
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Cited by 294 (15 self)
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Iterative algorithms for phase retrieval from intensity data are compared to gradient search methods. Both the problem of phase retrieval from two intensity measurements (in electron microscopy or wave front sens-ing) and the problem of phase retrieval from a single intensity measurement plus a non
Verbs and Adverbs: Multidimensional Motion Interpolation Using Radial Basis Functions
- IEEE Computer Graphics and Applications
, 1998
"... This paper describes methods and data structures used to leverage motion sequences of complex linked figures. We present a technique for interpolating between example motions derived from live motion capture or produced through traditional animation tools. These motions can be characterized by emoti ..."
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Cited by 351 (5 self)
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them, allowing an animated figure to exhibit a substantial repertoire of expressive behaviors. A combination of radial basis functions and low order polynomials is used to create the interpolation space between example motions. Inverse kinematic constraints are used to augment the interpolations
Is there a phase constraint for solar dynamo models?” Astron. Astrophys
, 2005
"... Received; accepted Abstract. The spatio-temporal relationship between the sign of the observed radial component of the magnetic field at the solar surface and the sign of the toroidal field as inferred from Hale’s polarity rules for sunspots is usually interpreted as signifying the phase relation be ..."
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Cited by 1 (0 self)
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between the poloidal and the toroidal magnetic field components involved in the solar dynamo process. This has been taken as a constraint for models of the solar dynamo. This note draws attention to the fact that the observed phase relation is naturally and inevitably produced by the emergence of tilted
Optimal Birth Control of Population Dynamics. II. Problems with Free Final Time, Phase Constraints, and Mini-Max Costs*
, 1988
"... We study optimal birth control of population systems of McKendrick type which is a distributed parameter system involving first order partial differential equations with nonlocal bilinear boundary control. New results on problems with free final time, phase constraints, and mini-max costs are presen ..."
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Cited by 1 (0 self)
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We study optimal birth control of population systems of McKendrick type which is a distributed parameter system involving first order partial differential equations with nonlocal bilinear boundary control. New results on problems with free final time, phase constraints, and mini-max costs
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