2,744 research outputs found
Measurement of the D-D fusion neutron energy spectrum and variation of the peak width with plasma ion temperature
and disposal, in whole or in part by or for the United States govern-ment is permitted. By acceptance of this article, the publisher and/or recipient ac-knowledges the U.S. Government's right to retain a non-exclusive, royalty-free license in and to any copyright covering this paper. 1 Measurement of the d-d fusion neutron energy spectrum and variation of the peak width with plasma ion temperature W. A. Fisher*, S. H. Chen*, D. Gwinnt, R. R. Parkert We report a set of neutron spectrum measurements made at the Alcator C tokamak under ohmic heating conditions. It has been found that the width of the D-D fusion neutron peak increases with the plasma ion temperature consistent with the theoretical prediction. In particular the neutron spectra resulting from the sum of many plasma discharges with ion temperatures of 780 eV and 1050 eV have been ob-tained. The width for the 780 eV case is 64 +9,-11 keV and that of the 1050 eV case, 81 +10,-14 keV FWHM, corresponding to ion tempera-tures of 740 eV and 1190 eV respectively
Deep finger texture learning for verifying people
Finger Texture (FT) is currently attracting significant attentions in the area of human recognition. Finger texture covers the area between the lower knuckle of the finger and the upper phalanx before the fingerprint. It involves rich features which can be efficiently used as a biometric characteristic. In this paper, we contribute to this growing area by proposing a new verification
approach, i.e., Deep Finger Texture Learning (DFTL). To the best of our knowledge, this is the first time that deep learning is employed for recognizing people by using the FT characteristic. Four databases have been used to evaluate the proposed method: the Hong Kong Polytechnic University Contact-free 3D/2D (PolyU2D), Indian Institute of Technology Delhi (IITD), CASIA Blue spectral (CASIA-BLU) corresponding to spectral 460nm and CASIA White spectral (CASIA-WHT) from the CASIA Multi-Spectral images database. The obtained results have shown superior performance compared with recent literature. The Verification Accuracies (VAs) have attained 100%, 98.65%, 100% and 98% for the four databases of PolyU2D, IITD, CASIA-BLU and CASIA-WHT, respectively
Generating dynamic higher-order Markov models in web usage mining
Markov models have been widely used for modelling users’ web navigation behaviour. In previous work we have presented a dynamic clustering-based Markov model that accurately represents second-order transition probabilities given by a collection of navigation sessions. Herein, we propose a generalisation of the method that takes into account higher-order conditional probabilities. The method makes use of the state cloning concept together with a clustering technique to separate the navigation paths that reveal differences in the conditional probabilities. We report on experiments conducted with three real world data sets. The results show that some pages require a long history to understand the users choice of link, while others require only a short history. We also show that the number of additional states induced by the method can be controlled through a probability threshold parameter
Partially spin polarized quantum Hall effect in the filling factor range 1/3 < nu < 2/5
The residual interaction between composite fermions (CFs) can express itself
through higher order fractional Hall effect. With the help of diagonalization
in a truncated composite fermion basis of low-energy many-body states, we
predict that quantum Hall effect with partial spin polarization is possible at
several fractions between and . The estimated excitation
gaps are approximately two orders of magnitude smaller than the gap at
, confirming that the inter-CF interaction is extremely weak in higher
CF levels.Comment: 4 pages, 3 figure
Horava-Lifshitz Dark Energy
We formulate Horava-Lifshitz cosmology with an additional scalar field that
leads to an effective dark energy sector. We find that, due to the inherited
features from the gravitational background, Horava-Lifshitz dark energy
naturally presents very interesting behaviors, possessing a varying
equation-of-state parameter, exhibiting phantom behavior and allowing for a
realization of the phantom divide crossing. In addition, Horava-Lifshitz dark
energy guarantees for a bounce at small scale factors and it may trigger the
turnaround at large scale factors, leading naturally to cyclic cosmology.Comment: 17 pages, no figures, version published at EJP
Using Markov Models and Statistics to Learn, Extract, Fuse, and Detect Patterns in Raw Data
Many systems are partially stochastic in nature. We have derived data driven
approaches for extracting stochastic state machines (Markov models) directly
from observed data. This chapter provides an overview of our approach with
numerous practical applications. We have used this approach for inferring
shipping patterns, exploiting computer system side-channel information, and
detecting botnet activities. For contrast, we include a related data-driven
statistical inferencing approach that detects and localizes radiation sources.Comment: Accepted by 2017 International Symposium on Sensor Networks, Systems
and Securit
Quasi-Periodic Releases of Streamer Blobs and Velocity Variability of the Slow Solar Wind near the Sun
We search for persistent and quasi-periodic release events of streamer blobs
during 2007 with the Large Angle Spectrometric Coronagraph on the \textit{Solar
and Heliospheric Observatory} and assess the velocity of the slow solar wind
along the plasma sheet above the corresponding streamer by measuring the
dynamic parameters of blobs. We find 10 quasi-periodic release events of
streamer blobs lasting for three to four days. In each day of these events, we
observe three-five blobs. The results are in line with previous studies using
data observed near the last solar minimum. Using the measured blob velocity as
a proxy for that of the mean flow, we suggest that the velocity of the
background slow solar wind near the Sun can vary significantly within a few
hours. This provides an observational manifestation of the large velocity
variability of the slow solar wind near the Sun.Comment: 14 pages, 5 figures, accepted by Soalr Physic
Two Unrelated 8-Vinyl Reductases Ensure Production of Mature Chlorophylls in Acaryochloris marina
The major photopigment of the cyanobacterium
Acaryochloris marina
is chlorophyll
d
, while its direct biosynthetic precursor,
chlorophyll
a
, is also present in the cell. These pigments, along with the majority of chlorophylls utilized by oxygenic pho-
totrophs, carry an ethyl group at the C-8 position of the molecule, having undergone reduction of a vinyl group during biosyn-
thesis. Two unrelated classes of 8-vinyl reductase involved in the biosynthesis of chlorophylls are known to exist, BciA and BciB.
The genome of
Acaryochloris marina
contains open reading frames (ORFs) encoding proteins displaying high sequence similarity to BciA or BciB, although they are annotated as genes involved in transcriptional control (
nmrA
) and methanogenesis (
frhB
),
respectively. These genes were introduced into an 8-vinyl chlorophyll
a
-producing
delta
bciB
strain of
Synechocystis
sp. strain PCC
6803, and both were shown to restore synthesis of the pigment with an ethyl group at C-8, demonstrating their activities as 8-vinyl reductases. We propose that
nmrA
and
frhB
be reassigned as
bciA
and
bciB
, respectively; transcript and proteomic analysis of
Acaryochloris marina
reveal that both
bciA
and
bciB
are expressed and their encoded proteins are present in the cell, possibly in
order to ensure that all synthesized chlorophyll pigment carries an ethyl group at C-8. Potential reasons for the presence of two
8-vinyl reductases in this strain, which is unique for cyanobacteria, are discussed
Euclidean wormholes with Phantom field and Phantom field accompanied by perfect fluid
We study the classical Euclidean wormhole solutions for the gravitational
systems with minimally coupled pure Phantom field and minimally coupled Phantom
field accompanied by perfect fluid. It is shown that such solutions do exist
and then the general forms of the Phantom field potential are obtained for
which there are classical Euclidean wormhole solutions.Comment: 15 pages, major revision with perfect flui
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