The Experts below are selected from a list of 2184 Experts worldwide ranked by ideXlab platform
Yuedong Wang - One of the best experts on this subject based on the ideXlab platform.
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low rank approximation for smoothing spline via Eigensystem truncation
arXiv: Machine Learning, 2019Co-Authors: Danqing Xu, Yuedong WangAbstract:Smoothing splines provide a powerful and flexible means for nonparametric estimation and inference. With a cubic time complexity, fitting smoothing spline models to large data is computationally prohibitive. In this paper, we use the theoretical optimal eigenspace to derive a low rank approximation of the smoothing spline estimates. We develop a method to approximate the Eigensystem when it is unknown and derive error bounds for the approximate estimates. The proposed methods are easy to implement with existing software. Extensive simulations show that the new methods are accurate, fast, and compares favorably against existing methods.
Abel Klein - One of the best experts on this subject based on the ideXlab platform.
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an Eigensystem approach to anderson localization
Journal of Functional Analysis, 2016Co-Authors: Alexander Elgart, Abel KleinAbstract:Abstract We introduce a new approach for proving localization (pure point spectrum with exponentially decaying eigenfunctions, dynamical localization) for the Anderson model at high disorder. In contrast to the usual strategy, we do not study finite volume Green's functions. Instead, we perform a multiscale analysis based on finite volume Eigensystems (eigenvalues and eigenfunctions). Information about Eigensystems at a given scale is used to derive information about Eigensystems at larger scales. This Eigensystem multiscale analysis treats all energies of the finite volume operator at the same time, establishing level spacing and localization of eigenfunctions in a fixed box with high probability. A new feature is the labeling of the eigenvalues and eigenfunctions by the sites of the box.
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Eigensystem Bootstrap Multiscale Analysis for the Anderson Model
arXiv: Mathematical Physics, 2016Co-Authors: Abel Klein, C. S. Sidney TsangAbstract:We use a bootstrap argument to enhance the Eigensystem multiscale analysis, introduced by Elgart and Klein for proving localization for the Anderson model at high disorder. The Eigensystem multiscale analysis studies finite volume Eigensystems, not finite volume Green's functions. It yields pure point spectrum with exponentially decaying eigenfunctions and dynamical localization. The starting hypothesis for the Eigensystem bootstrap multiscale analysis only requires the verification of polynomial decay of the finite volume eigenfunctions, at some sufficiently large scale, with some minimal probability independent of the scale. It yields exponential localization of finite volume eigenfunctions in boxes of side $L$, with the eigenvalues and eigenfunctions labeled by the sites of the box, with probability higher than $1-\mathrm{e}^{-L^\xi}$, for any desired $0
Danqing Xu - One of the best experts on this subject based on the ideXlab platform.
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low rank approximation for smoothing spline via Eigensystem truncation
arXiv: Machine Learning, 2019Co-Authors: Danqing Xu, Yuedong WangAbstract:Smoothing splines provide a powerful and flexible means for nonparametric estimation and inference. With a cubic time complexity, fitting smoothing spline models to large data is computationally prohibitive. In this paper, we use the theoretical optimal eigenspace to derive a low rank approximation of the smoothing spline estimates. We develop a method to approximate the Eigensystem when it is unknown and derive error bounds for the approximate estimates. The proposed methods are easy to implement with existing software. Extensive simulations show that the new methods are accurate, fast, and compares favorably against existing methods.
Qingkai Meng - One of the best experts on this subject based on the ideXlab platform.
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power system osciliation modes identification based on eigen system realization algorithm via empirical mode decomposition
Energy Procedia, 2012Co-Authors: Yunran Wang, Jianbo Wang, Qingkai MengAbstract:Abstract With the application of wide-area measurement system (WAMS), the analysis of dynamic behavior of power system based on swing tracks acts as an important research field and is different from the past methods based on a given mathematical models. In this paper,EMD-based Eigensystem realization algorithm is proposed for identifying frequency, damping and vibration in the low frequency oscillationidentify for low frequency oscillation frequency, damping and vibration. Through a example of a four-machine two-region system, it is proved that this method on distinguishing the oscillation frequency, damping ratio and mode shapes is validity. This method can be minimal realization of the system, damping controller for the design conditions.this method can achieve the simplest state space modal of system. It is important for designer to invent advanced damping controller.
A De Stefano - One of the best experts on this subject based on the ideXlab platform.
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output only modal identification of ancient l aquila city hall and civic tower
Journal of Structural Engineering-asce, 2012Co-Authors: Gian Paolo Cimellaro, S Pianta, A De StefanoAbstract:The ancient masonry city hall in L'Aquila, Italy (Margherita Palace) that was severely damaged during the L'Aquila earthquake in April 2009 has been subjected to ambient vibration tests to determine its dynamic characteristics such as the natural frequencies, mode shapes, and damping ratios. The processing of ambient vibration responses is performed with three output-only identification approaches: (1) the frequency-domain decomposition, (2) random decrement (RD) technique combined with the Eigensystem realization algorithm (ERA), and (3) the natural excitation technique (NExT) combined with ERA. Measurements were made in the palace and in the civic tower using 15 sensors in three different configurations, and the ambient vibration tests involved the simultaneous measurements of longitudinal and lateral vibrations. Lateral vibration modes for the civic tower were identified clearly; a total of five modal shapes and frequencies were identified in the frequency range 0 to 7 Hz. The modal identification in the palace was more difficult because of the severe damage; however, the two bending modes in the perpendicular directions were identified. The comparison of the three experimental techniques shows good agreement, confirming the reliability of the three identification methods. The results of the modal identification have been used to update the finite-element model of the palace. DOI: 10.1061/(ASCE)ST.1943-541X.0000494. © 2012 American Society of Civil Engineers. CE Database subject headings: Historic buildings; Masonry; Finite element method; Vibration; Structural analysis; Earthquakes; Italy. Author keywords: Output-only modal identification; Frequency domain decomposition (FDD); Eigensystem realization algorithm (ERA); Random decrement (RD); Masonry structure; Finite-element model; Ambient vibration; Identification; EMA; Operational modal analysis.