24,976 research outputs found
Light Reflectance Characteristics and Remote Sensing of Waterlettuce
Waterlettuce (
Pistia stratiotes
L.) is a free-floating exotic
aquatic weed that often invades and clogs waterways in the
southeastern United States. A study was conducted to evaluate
the potential of using remote sensing technology to distinguish
infestations of waterlettuce in Texas waterways. Field
reflectance measurements showed that waterlettuce had
higher visible green reflectance than associated plant species.
Waterlettuce could be detected in both aerial color- infrared
(CIR) photography and videography where it had
light pink to pinkish-white image tonal responses. Computer
analysis of CIR photographic and videographic images had
overall accuracy assessments of 86% and 84%, respectively. (PDF contains 6 pages.
Coulomb Oscillations of Indium-doped ZnO Nanowire Transistors in a Magnetic Field
We report on the observation of Coulomb oscillations from localized quantum
dots superimposed on the normal hopping current in ZnO nanowire transistors.
The Coulomb oscillations can be resolved up to 20 K. Positive anisotropic
magnetoresistance has been observed due to the Lorentz force on the carrier
motion. Magnetic field-induced tunneling barrier transparency results in an
increase of oscillation amplitude with increasing magnetic field. The energy
shift as a function of magnetic field indicates electron wavefunction
modification in the quantum dots.Comment: 16 pages, 6 figure
Effects of neutrino mass hierarchies on dynamical dark energy models
We investigate how three different possibilities of neutrino mass
hierarchies, namely normal, inverted, and degenerate, can affect the
observational constraints on three well known dynamical dark energy models,
namely the Chevallier-Polarski-Linder, logarithmic, and the
Jassal-Bagla-Padmanabhan parametrizations. In order to impose the observational
constraints on the models, we performed a robust analysis using Planck 2015
temperature and polarization data, Supernovae type Ia from Joint Light curve
analysis, baryon acoustic oscillations distance measurements, redshift space
distortion characterized by data, weak gravitational lensing
data from Canada-France-Hawaii Telescope Lensing Survey, and cosmic
chronometers data plus the local value of the Hubble parameter. We find that
different neutrino mass hierarchies return similar fit on almost all model
parameters and mildly change the dynamical dark energy properties.Comment: 10 pages, 5 captioned figures, 4 tables; Published version in Phys.
Rev.
Fabrication of transparent conducting amorphous Zn–Sn–In–O thin films by direct current magnetron sputtering
Amorphous ZnO–SnO2–In2O3 films were grown by direct current magnetron sputtering from vacuum hot pressed ceramic oxide targets of Zn:In:Sn cation ratios 1:2:1 and 1:2:1.5 onto glass substrates. X-ray diffraction analysis showed that the microstructure remained amorphous during annealing at 200 °C for up to 5 hours. By monitoring the electrical resistivity, oxygen content and substrate temperature were optimized during deposition. The optimal films were characterized by Hall Effect, work function and optical spectroscopy measurements. Films of 1:2:1 composition showed the lowest resistivity (7.6×10−4 Ω-cm), when deposited onto substrates preheated to 300 °C. Transmissivity of all films exceeded 80% in the visible spectral region. The energy gap was 3.52–3.74 eV, and the work function ranged 5.08–5.22 eV, suitable for cathode applications in organic light emitting diodes. Overall, the film characteristics were comparable or superior to those of amorphous tin-doped indium oxide and zinc-doped indium oxide films and may serve as viable, lower-cost alternatives
Calibrated Fairness in Bandits
We study fairness within the stochastic, \emph{multi-armed bandit} (MAB)
decision making framework. We adapt the fairness framework of "treating similar
individuals similarly" to this setting. Here, an `individual' corresponds to an
arm and two arms are `similar' if they have a similar quality distribution.
First, we adopt a {\em smoothness constraint} that if two arms have a similar
quality distribution then the probability of selecting each arm should be
similar. In addition, we define the {\em fairness regret}, which corresponds to
the degree to which an algorithm is not calibrated, where perfect calibration
requires that the probability of selecting an arm is equal to the probability
with which the arm has the best quality realization. We show that a variation
on Thompson sampling satisfies smooth fairness for total variation distance,
and give an bound on fairness regret. This complements
prior work, which protects an on-average better arm from being less favored. We
also explain how to extend our algorithm to the dueling bandit setting.Comment: To be presented at the FAT-ML'17 worksho
Column froth flotation
The froth flotation device includes a flotation column partially filled with a packing which defines a large number of small flow passages extending in a circuitous pattern between the upper and lower portions of the column. A conditioned aqueous pulp of a mineral ore, such as iron ore, is introduced into the midzone of the column. A pressurized inert gas, such as air, is introduced into the bottom of the column and is forced upwardly through the flow passages in the packing. As the air flows upwardly through these flow passages, it is broken into fine bubbles which intimately contact the floatable particles (e.g., iron oxide) in the aqueous pulp and forms a froth concentrate or float fraction which overflows from the top of the column. Wash water is introduced into the top of the column and flows through the flow passages in the packing countercur- rently to the float fraction to scrub entrained non-floata- ble particles (e.g., gangue) from the froth concentrate. A tailing fraction containing the non-floatable particles is withdrawn from the bottom of the column.https://digitalcommons.mtu.edu/patents/1101/thumbnail.jp
HRTEM study of a new non-stoichiometric BaTiO(3-δ) structure
BaTiO3-based multilayer ceramic capacitors (MLCCs) with Ni internal electrodes are co-fired in
reducing atmospheres to avoid oxidation of the electrode. Although dielectric materials are doped by
acceptor, donor and amphoteric dopants to minimize the oxygen vacancy content, there is still a
large concentration of oxygen vacancies that are accommodated in the BaTiO3 active layers. In
general, ABO3 perovskites demonstrates a strong ability to accommodate the oxygen vacancies and
maintain a regular pseudo-cubic structure. Oxygen deficient barium titanate can be transformed to a
hexagonal polymorph (h-BT) at high temperatures1,2. In this paper, we report the new modulated and
long range ordered structures of non-stoichiometric BaTiO3-δ that are observed in the electrically
degraded Ni-BaTiO3 MLCCs at low temperature
An MRI-Derived Definition of MCI-to-AD Conversion for Long-Term, Automati c Prognosis of MCI Patients
Alzheimer's disease (AD) and mild cognitive impairment (MCI), continue to be
widely studied. While there is no consensus on whether MCIs actually "convert"
to AD, the more important question is not whether MCIs convert, but what is the
best such definition. We focus on automatic prognostication, nominally using
only a baseline image brain scan, of whether an MCI individual will convert to
AD within a multi-year period following the initial clinical visit. This is in
fact not a traditional supervised learning problem since, in ADNI, there are no
definitive labeled examples of MCI conversion. Prior works have defined MCI
subclasses based on whether or not clinical/cognitive scores such as CDR
significantly change from baseline. There are concerns with these definitions,
however, since e.g. most MCIs (and ADs) do not change from a baseline CDR=0.5,
even while physiological changes may be occurring. These works ignore rich
phenotypical information in an MCI patient's brain scan and labeled AD and
Control examples, in defining conversion. We propose an innovative conversion
definition, wherein an MCI patient is declared to be a converter if any of the
patient's brain scans (at follow-up visits) are classified "AD" by an
(accurately-designed) Control-AD classifier. This novel definition bootstraps
the design of a second classifier, specifically trained to predict whether or
not MCIs will convert. This second classifier thus predicts whether an
AD-Control classifier will predict that a patient has AD. Our results
demonstrate this new definition leads not only to much higher prognostic
accuracy than by-CDR conversion, but also to subpopulations much more
consistent with known AD brain region biomarkers. We also identify key
prognostic region biomarkers, essential for accurately discriminating the
converter and nonconverter groups
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