4,611 research outputs found
Dissimilarity-based representation for radiomics applications
Radiomics is a term which refers to the analysis of the large amount of
quantitative tumor features extracted from medical images to find useful
predictive, diagnostic or prognostic information. Many recent studies have
proved that radiomics can offer a lot of useful information that physicians
cannot extract from the medical images and can be associated with other
information like gene or protein data. However, most of the classification
studies in radiomics report the use of feature selection methods without
identifying the machine learning challenges behind radiomics. In this paper, we
first show that the radiomics problem should be viewed as an high dimensional,
low sample size, multi view learning problem, then we compare different
solutions proposed in multi view learning for classifying radiomics data. Our
experiments, conducted on several real world multi view datasets, show that the
intermediate integration methods work significantly better than filter and
embedded feature selection methods commonly used in radiomics.Comment: conference, 6 pages, 2 figure
Phase Change Material Photonics
In the last decade phase change materials (PCM) research has switched from
practical application in optical data storage toward electrical phase change
random access memory technologies (PCRAM). As these devices are commercialised,
we expect the research direction to switch once again toward
electrical-photonic devices. The objective of this review is to introduce the
concepts in PCM-tuned photonics. We will start by highlighting the key works in
the field, before concentrating on PCM-tuned Metal-Dielectric-Metal (MDM)
structures. We will discuss how to design tuneable-MDM photonics devices, their
advantages, and their limitations. Finally we will discuss new materials for
phase change photonics.Comment: 28 pages, 14 figures, adapted from a chapter to be published in the
World Scientific Reference of Amorphous Material
Photoluminescence modification by high-order photonic band with abnormal dispersion in ZnO inverse opal
We measured the angle- and polarization-resolved reflection and
photoluminescence spectra of ZnO inverse opals. Significant enhancement of
spontaneous emission is observed. The enhanced emission not only has good
directionality but also can be linearly polarized. A detailed theoretical
analysis and numerical simulation reveal that such enhancement is caused by the
abnormal dispersion of a high-order photonic band. The frozen mode at a
stationary inflection point of a dispersion curve can strongly modify the
intensity, directionality and polarization of spontaneous emission.Comment: 22 pages, 11 figures, figures modified, references added, more
explanation adde
Electrical field assisted sintering of yttrium-doped ceria investigated by sinter-forging
The production of traditional and advanced ceramics is an energy-intensive activity, which requires high sintering temperatures and long holding times to activate diffusional processes necessary for densification. Electric field assisted processing has the potential to significantly reduce the sintering time and temperature which are not obtainable by other methods. The role of electric fields in the densification and coarsening of oxide ceramics is still under debate. By using a sinter-forging device equipped with a versatile power source and high-resolution laser scanners, it is possible to investigate in detail field assisted sintering process by quantifying uniaxial viscosity, viscous Poisson’s ratio and sintering stress of oxide ceramics. The macroscopic Joule heating effect was eliminated by using Finite-Element Simulations calibrated experimentally and by lowering the furnace temperature accordingly. In other words, the sample temperature was kept constant under the different testing conditions, enabling a correct estimation of a thermal electric field effects. The sintering parameters of the ceramic pellets were measured without / with alternating electrical field well below flash sintering conditions. Clear effect of the electrical field on both uniaxial viscosity and sintering stress were observed. Microstructures of the specimens were investigated by SEM and TEM, and correlated to the electrical properties of the samples measured by Electrochemical Impedance Spectroscopy in order to understand the interplay between grain boundaries and electric field
Intertwined magnetic and nematic orders in semiconducting KFeAgTe
Superconductivity in the iron pnictides emerges from metallic parent
compounds exhibiting intertwined stripe-type magnetic order and nematic order,
with itinerant electrons suggested to be essential for both. Here we use X-ray
and neutron scattering to show that a similar intertwined state is realized in
semiconducting KFeAgTe (KFeAgTe) without
itinerant electrons. We find Fe atoms in KFeAgTe form
isolated blocks, separated by nonmagnetic Ag atoms. Long-range
magnetic order sets in below K, with magnetic moments
within the Fe blocks ordering into the stripe-type configuration. A
nematic order accompanies the magnetic transition, manifest as a structural
distortion that breaks the fourfold rotational symmetry of the lattice. The
nematic orders in KFeAgTe and iron pnictide parent
compounds are similar in magnitude and how they relate to the magnetic order,
indicating a common origin. Since KFeAgTe is a
semiconductor without itinerant electrons, this indicates that local-moment
magnetic interactions are integral to its magnetic and nematic orders, and such
interactions may play a key role in iron-based superconductivity.Comment: supplemental material available upon request, to be published in PR
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