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Truncated sparse approximation property and truncated q-norm minimization
CHEN Wen-gu LI Peng
Applied Mathematics-A Journal of Chinese Universities, 2019, 34(3): 261-283.
https://doi.org/10.1007/s11766-019-3596-2
This paper considers approximately sparse signal and low-rank matrix’s recovery via truncated norm minimization min_x ∥xT ∥q and min_X ∥XT ∥Sq from noisy measurements. We first introduce truncated sparse approximation property, a more general robust null space property, and establish the stable recovery of signals and matrices under the truncated sparse approximation property. We also explore the relationship between the restricted isometry property and truncated sparse approximation property. And we also prove that if a measurement matrix A or linear map A satisfies truncated sparse approximation property of order k, then the first inequality in restricted isometry property of order k and of order 2k can hold for certain different constants δk and δ2k, respectively. Last, we show that if δ_{s(k+jTcj)} <\sqrt{(s - 1)/s} for some s ≥ 4/3, then measurement matrix A and linear map A satisfy truncated sparse approximation property of order k. It should be pointed out that when T^c =\Phi, our conclusion implies that sparse approximation property of order k is weaker than restricted isometry property of order sk.
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Gregory Solid Construction for Polyhedral Volume Parameterization by Sparse Optimization
HU Chuan-feng LIN Hong-wei
Applied Mathematics-A Journal of Chinese Universities, 2019, 34(3): 340-355.
https://doi.org/10.1007/s11766-019-3697-y
In isogeometric analysis, it is frequently required to handle the geometric models enclosed by four-sided or non-four-sided boundary patches, such as trimmed surfaces. In this paper, we develop a Gregory solid based method to parameterize those models. First, we extend the Gregory patch representation to the trivariate Gregory solid representation. Second, the trivariate Gregory solid representation is employed to interpolate the boundary patches of a geometric model, thus generating the polyhedral volume parametrization. To improve the regularity of the polyhedral volume parametrization, we formulate the construction of the trivariate Gregory solid as a sparse optimization problem, where the optimization objective function is a linear combination of some terms, including a sparse term aiming to reduce the negative Jacobian area of the Gregory solid. Then, the alternating direction method of multipliers (ADMM) is used to solve the sparse optimization problem. Lots of experimental examples illustrated in this paper demonstrate the effectiveness and efficiency of the developed method.
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7 articles
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