We present a reduced order finite element (FE) algorithm suitable for real-time nonlinear simulation of soft tissues. A dynamic FE formulation with explicit time integration is employed. We demonstrate significant computation acceleration by performing the time integration in a low-dimensional generalised basis, generated from a set of a priori training simulations. The key mechanism for the acceleration is the large increase in integration time step afforded by this means. Futhermore, we present a simple procedure for imposing inhomogeneous essential boundary conditions, thus overcoming one of the principal deficiencies of such approaches. The algorithm is described and demonstrated using an example neurosurgical simulation. The computation acceleration and errors introduced are examined.
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http://dx.doi.org/10.1109/IEMBS.2010.5627720 | DOI Listing |
J Opt Soc Am A Opt Image Sci Vis
August 2024
In order to improve the accuracy of camera colorimetric characterization, a multi-input parameter optimization method was proposed in this paper. The input parameters of the traditional camera characterization method were generally RGB values; in the proposed method, the luminance parameter L was introduced in addition to RGB values, and the four-input parameters of RGBL were used as input parameters for the conversion model. In the experiment, 549 colors were uniformly selected from the Munsell Book of Color (Matte Edition), and the RGBL values and corresponding CIEXYZ values of the selected colors were measured by a spectroradiometer and three cameras, including an imaging luminance meter, respectively.
View Article and Find Full Text PDFJ Opt Soc Am A Opt Image Sci Vis
August 2024
Frequency-domain near-infrared spectroscopy (FD-NIRS) is a noninvasive method for quantitatively measuring optical absorption and scattering in tissue. This study introduces structured interrogation (SI) as an interference-based approach for implementing FD-NIRS in order to enhance optical property estimation in multilayered tissues and sensitivity to deeper layers. We find that, in the presence of realistic noise, SI accurately estimates properties and chromophore concentrations with less than a 5% error.
View Article and Find Full Text PDFJ Phys Chem A
January 2025
Center for Satellite Application on Environment, Ministry of Ecology and Environment, Beijing 100094, China.
The edge structures of carbonaceous materials exhibit temperature-dependent behavior on the atomic scale, with variations in the relative ratios of zigzag, reconstructed 5-7 zigzag (ZZ57), and armchair edges observed at different temperatures. Nevertheless, the mechanisms underlying the interconversion of these edge structures and the influence of the surrounding metals remain unclear. This study investigates the reconstruction and reversible transformation processes of ZZ57 edge structures in carbon materials and examines the effects of different metal atoms (Na, K, and Ca) by using density functional theory.
View Article and Find Full Text PDFIEEE Trans Antennas Propag
December 2024
National Institute of Standards and Technology, Boulder CO 80305.
In this paper we describe an enhanced three-antenna gain extrapolation technique that allows one to determine antenna gain with significantly fewer data points and at closer distances than with the well-established traditional three-antenna gain extrapolation technique that has been in use for over five decades. As opposed to the traditional gain extrapolation technique, where high-order scattering is purposely ignored so as to isolate only the direct antenna-to-antenna coupling, we show that by incorporating third-order scattering the enhanced gain extrapolation technique can be obtained. The theoretical foundation using third-order scattering is developed and experimental results are presented comparing the enhanced technique and traditional technique for two sets of internationally recognized NIST reference standard gain horn antennas at X-band and Ku-band.
View Article and Find Full Text PDFHeliyon
January 2025
University of Campinas, School of Food Engineering, 13056-405, Campinas, SP, Brazil.
The aim of this study was to examine the drying kinetics of L. fruits at various maturation stages (I to V) using a range of mathematical models (Henderson and Pabis, Lewis, Logarithmic, Midilli, and Page). Additionally, an assessment of the resulting flours' quality was conducted.
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