99,104 research outputs found
Length Dependent Thermal Conductivity Measurements Yield Phonon Mean Free Path Spectra in Nanostructures
Thermal conductivity measurements over variable lengths on nanostructures
such as nanowires provide important information about the mean free paths
(MFPs) of the phonons responsible for heat conduction. However, nearly all of
these measurements have been interpreted using an average MFP even though
phonons in many crystals possess a broad MFP spectrum. Here, we present a
reconstruction method to obtain MFP spectra of nanostructures from
variable-length thermal conductivity measurements. Using this method, we
investigate recently reported length-dependent thermal conductivity
measurements on SiGe alloy nanowires and suspended graphene ribbons. We find
that the recent measurements on graphene imply that 70 % of the heat in
graphene is carried by phonons with MFPs longer than 1 micron
Graph Scaling Cut with L1-Norm for Classification of Hyperspectral Images
In this paper, we propose an L1 normalized graph based dimensionality
reduction method for Hyperspectral images, called as L1-Scaling Cut (L1-SC).
The underlying idea of this method is to generate the optimal projection matrix
by retaining the original distribution of the data. Though L2-norm is generally
preferred for computation, it is sensitive to noise and outliers. However,
L1-norm is robust to them. Therefore, we obtain the optimal projection matrix
by maximizing the ratio of between-class dispersion to within-class dispersion
using L1-norm. Furthermore, an iterative algorithm is described to solve the
optimization problem. The experimental results of the HSI classification
confirm the effectiveness of the proposed L1-SC method on both noisy and
noiseless data.Comment: European Signal Processing Conference 201
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