The Experts below are selected from a list of 252 Experts worldwide ranked by ideXlab platform
Yoshihisa Yamamoto - One of the best experts on this subject based on the ideXlab platform.
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simultaneous coulomb blockade for electrons and holes in p n junctions observation of coulomb Staircase and turnstile operation
Physica E-low-dimensional Systems & Nanostructures, 2000Co-Authors: Oliver Benson, Jungsang Kim, Hirofumi Kan, Yoshihisa YamamotoAbstract:Abstract The Coulomb blockade Effect in a mesoscopic double-barrier p–i–n junction is reported. The electron and hole injection into the central QW of a p–n junction is achieved via resonant tunneling. We present a theoretical model that describes the device operation. When the device is biased with a constant voltage source the model predicts the observation of Coulomb Staircase in the current–voltage characteristics. When an additional square wave modulation signal is applied, turnstile operation is achieved. The experimental evidence for Coulomb Staircase Effect and turnstile operation is presented.
Jun Liu - One of the best experts on this subject based on the ideXlab platform.
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total variation with overlapping group sparsity for speckle noise reduction
Neurocomputing, 2016Co-Authors: Jun Liu, Tingzhu Huang, Gang Liu, Si WangAbstract:Staircase Effect usually happens on the total variation (TV) regularized solutions, while the overlapping group sparsity total variation (OGSTV) as a regularization has been proved to be Effective for alleviating this drawback. For coherent imaging systems, such as the synthetic aperture radar, the acquired images are corrupted by speckles. In this paper, we propose a speckle noise reduction model based on the regularization of OGSTV. Under the framework of efficient alternating direction method of multipliers, we develop the corresponding algorithm for solving the proposed model. Numerical experiments are presented to illustrate the superiority of the proposed model and efficiency of the corresponding algorithm.
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image restoration using total variation with overlapping group sparsity
arXiv: Computer Vision and Pattern Recognition, 2013Co-Authors: Jun Liu, Tingzhu Huang, Ivan W Selesnick, Poyu ChenAbstract:Image restoration is one of the most fundamental issues in imaging science. Total variation (TV) regularization is widely used in image restoration problems for its capability to preserve edges. In the literature, however, it is also well known for producing Staircase-like artifacts. Usually, the high-order total variation (HTV) regularizer is an good option except its over-smoothing property. In this work, we study a minimization problem where the objective includes an usual $l_2$ data-fidelity term and an overlapping group sparsity total variation regularizer which can avoid Staircase Effect and allow edges preserving in the restored image. We also proposed a fast algorithm for solving the corresponding minimization problem and compare our method with the state-of-the-art TV based methods and HTV based method. The numerical experiments illustrate the efficiency and Effectiveness of the proposed method in terms of PSNR, relative error and computing time.
Si Wang - One of the best experts on this subject based on the ideXlab platform.
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total variation with overlapping group sparsity for speckle noise reduction
Neurocomputing, 2016Co-Authors: Jun Liu, Tingzhu Huang, Gang Liu, Si WangAbstract:Staircase Effect usually happens on the total variation (TV) regularized solutions, while the overlapping group sparsity total variation (OGSTV) as a regularization has been proved to be Effective for alleviating this drawback. For coherent imaging systems, such as the synthetic aperture radar, the acquired images are corrupted by speckles. In this paper, we propose a speckle noise reduction model based on the regularization of OGSTV. Under the framework of efficient alternating direction method of multipliers, we develop the corresponding algorithm for solving the proposed model. Numerical experiments are presented to illustrate the superiority of the proposed model and efficiency of the corresponding algorithm.
Oliver Benson - One of the best experts on this subject based on the ideXlab platform.
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simultaneous coulomb blockade for electrons and holes in p n junctions observation of coulomb Staircase and turnstile operation
Physica E-low-dimensional Systems & Nanostructures, 2000Co-Authors: Oliver Benson, Jungsang Kim, Hirofumi Kan, Yoshihisa YamamotoAbstract:Abstract The Coulomb blockade Effect in a mesoscopic double-barrier p–i–n junction is reported. The electron and hole injection into the central QW of a p–n junction is achieved via resonant tunneling. We present a theoretical model that describes the device operation. When the device is biased with a constant voltage source the model predicts the observation of Coulomb Staircase in the current–voltage characteristics. When an additional square wave modulation signal is applied, turnstile operation is achieved. The experimental evidence for Coulomb Staircase Effect and turnstile operation is presented.
Gabriel A Elgavish - One of the best experts on this subject based on the ideXlab platform.
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23na nmr shift reagents enhance cardiac Staircase Effect in isolated perfused rat hearts
NMR in Biomedicine, 1999Co-Authors: Tamas Simor, Tamas Lorand, Aron Szollosy, Balazs Gaszner, Stanley B Digerness, Gabriel A ElgavishAbstract:The Effects of the currently used (23)Na NMR shift reagents, dysprosium bis-triphosphate [Dy(PPP)(2)], dysprosium triethylenetriamine hexaacetate [Dy(TTHA)] and thulium 1,4,7, 10-tetraazacyclododecane-N,N',N",N"'-tetra(methylenephosphonate) [Tm(DOTP)] were studied in the rat heart cardiac Staircase model. Rat hearts were perfused with low or normal extracellular free calcium ([Ca(o)](f)). At low [Ca(o)](f) (0.34 +/- 0.05 mM), hearts were perfused with Dy(PPP)(2) (group I), Dy(TTHA) (group II) or no shift reagent (group III), while at normal [Ca(o)](f) (1.25 +/- 0.15 mM), hearts were perfused with Tm(DOTP) (group IV), Dy(TTHA) (group V) or no shift reagent (group VI). Left ventricular developed pressure (LVDP) values in group I were significantly higher than in groups II and III (p < 0.01), while no significant differences were found between groups II and III. LVDP values in group IV were significantly higher than in groups V and VI (p < 0.05), while the LVDP values in groups V and VI were almost identical. Also, a positive correlation between pacing rate and intracellular sodium ([Na(i)]) was evident. The [Na(i)] values at high [Ca(o)](f) were significantly lower than at low [Ca(o)](f) at each pacing level (p <0.01), indicating a negative correlation between [Na(i)] and [Ca(o)](f). No statistical differences were found in [Na(i)] between groups I vs II and IV vs V, showing that determination of [Na(i)] is not affected by any of these shift reagents. Thus the different LVDP responses in groups I vs II and IV vs V were not mirrored in [Na(i)] changes. We hypothesize that a direct, sarcolemmal Ca-Dy(PPP)(2)-, or Ca-Tm(DOTP)-induced positive inotropic Effect could be responsible for these Na(i)-independent LVDP increases in groups I and IV.