Mode Selection Criterion Using Statistics for Direct Link Communication in Next Generation

2022 ◽  
pp. 225-233
Author(s):  
Pallavi Sapkale ◽  
Uttam Kolekar
Keyword(s):  
Mode Selection ◽  
Selection Criterion ◽  
Direct Link ◽  
Next Generation

scholarly journals Using spectral submanifolds for optimal mode selection in nonlinear model reduction

2021 ◽  
Vol 477 (2246) ◽  
pp. 20200725
Author(s):  
Gergely Buza ◽  
Shobhit Jain ◽  
George Haller
Keyword(s):  
Model Reduction ◽  
Invariant Manifolds ◽  
Mode Selection ◽  
Normal Modes ◽  
Selection Criterion ◽  
Selection Procedure ◽  
Forced Response ◽  
Recent Theory ◽  
Response Curves ◽  
Spectral Submanifolds

Model reduction of large nonlinear systems often involves the projection of the governing equations onto linear subspaces spanned by carefully selected modes. The criteria to select the modes relevant for reduction are usually problem-specific and heuristic. In this work, we propose a rigorous mode-selection criterion based on the recent theory of spectral submanifolds (SSMs), which facilitates a reliable projection of the governing nonlinear equations onto modal subspaces. SSMs are exact invariant manifolds in the phase space that act as nonlinear continuations of linear normal modes. Our criterion identifies critical linear normal modes whose associated SSMs have locally the largest curvature. These modes should then be included in any projection-based model reduction as they are the most sensitive to nonlinearities. To make this mode selection automatic, we develop explicit formulae for the scalar curvature of an SSM and provide an open-source numerical implementation of our mode-selection procedure. We illustrate the power of this procedure by accurately reproducing the forced-response curves on three examples of varying complexity, including high-dimensional finite-element models.

The Importance of Energy Criteria for Selecting Modes in Reduced Order Modeling

2019 ◽  
Author(s):  
Suparno Bhattacharyya ◽  
Joseph P. Cusumano
Keyword(s):  
Mode Selection ◽  
Selection Criterion ◽  
Fixed Amount ◽  
Reduced Order ◽  
New Energy ◽  
Total Data ◽  
Effective Dimensionality ◽  
Spatiotemporal Localization ◽  
Proper Orthogonal ◽  
Euler Bernoulli Beam

Abstract We study the performance of the proper orthogonal decomposition when used for model reduction of an Euler-Bernoulli beam subjected to periodic impulses. We assess the accuracy of reduced order models (ROMs) obtained using steady-state displacement time series. The spatiotemporal localization of the applied impulses is tuned to control the number of excited modes in, and hence the effective dimensionality of, the system’s response. We find that when the impacts are significantly localized (i.e., are more impulsive), the conventional variance-based mode selection criterion can lead to inaccurate ROMs. We show that this arises when the reduced subspace capturing a fixed amount (say, 99.9%) of the total data variance underestimates the energy input and/or dissipated in the ROM, leading to energy imbalance. We thus propose a new energy closure criterion that provides an improved method for generating ROMs. The energetics of the resulting ROMs properly reflect those of the full system, and yield simulations that accurately represent the system’s true behavior.

Spacings and Intensities of Weak-Beam Dark Field Thickness Fringes

1981 ◽  
Vol 39 ◽  
pp. 222-223
Author(s):  
M. Avalos-Borja ◽  
K. Heinemann
Keyword(s):  
Selection Criterion ◽  
Dark Field ◽  
Dynamical Theory ◽  
Bragg Condition ◽  
Weak Beam ◽  
Kinematical Theory ◽  
Equal Thickness

Weak-beam dark field (WBDF) TEM produces narrowly spaced equal-thickness fringes in wedge-shaped crystals. Using non-systematic diffraction conditions, we have shown elsewhere that simple 2-beam kinematical theory (KT) calculations yield average fringe spacings that are for most practical purposes as satisfactorily accurate as the average spacings obtained from optimized multibeam dynamical theory (DT) calculations, As Fig. 1 shows, this result holds for deviations from the Bragg condition as low as 2x10-1 nm-1, and the differences between the results from the two calculational methods become increasingly insignificant for larger excitation errors. (Unless otherwise noted, all results reported here are for gold crystals, using the 200 beam at 100 KV; the DT calculations were made for 74 beams, using the selection criterion D as discussed in ref. [3]).

1477: Durability of Next Generation Flexible Ureteroscopes: Randomized Prospective Study

2004 ◽  
Vol 171 (4S) ◽  
pp. 389-389
Author(s):  
Manoj Monga ◽  
Ramakrishna Venkatesh ◽  
Sara Best ◽  
Caroline D. Ames ◽  
Courtney Lee ◽  
...  
Keyword(s):  
Prospective Study ◽  
Next Generation ◽  
Flexible Ureteroscopes
Sign in / Sign up

Export Citation Format

Share Document