7,429 research outputs found
A Multi Hidden Recurrent Neural Network with a Modified Grey Wolf Optimizer
Identifying university students' weaknesses results in better learning and
can function as an early warning system to enable students to improve. However,
the satisfaction level of existing systems is not promising. New and dynamic
hybrid systems are needed to imitate this mechanism. A hybrid system (a
modified Recurrent Neural Network with an adapted Grey Wolf Optimizer) is used
to forecast students' outcomes. This proposed system would improve instruction
by the faculty and enhance the students' learning experiences. The results show
that a modified recurrent neural network with an adapted Grey Wolf Optimizer
has the best accuracy when compared with other models.Comment: 34 pages, published in PLoS ON
A Physical Theory of the Competition that Allows HIV to Escape from the Immune System
Competition within the immune system may degrade immune control of viral
infections. We formalize the evolution that occurs in both HIV-1 and the immune
system quasispecies. Inclusion of competition in the immune system leads to a
novel balance between the immune response and HIV-1, in which the eventual
outcome is HIV-1 escape rather than control. The analytical model reproduces
the three stages of HIV-1 infection. We propose a vaccine regimen that may be
able to reduce competition between T cells, potentially eliminating the third
stage of HIV-1.Comment: 5 pages, 2 figures, to appear in Phys. Rev. Let
Speed and Current Limiting Control Strategies for BLDC Motor Drive System: A Comparative Study
As a result of increasing the use of the brushless direct current (BLDC) motor in many life applications instead of the traditional motors, it is important to list and specify the more for its controlling methods. This paper presents a number of speed and current controlling methods as hysteresis band, variable dc-link bus voltage and pulse width modulation (PWM) controlling methods. These controlling methods have proportional integral derivative (PID) gains which are optimized by using particle swarm optimization (PSO) algorithm. By using fast Fourier transform (FFT) analysis to study the controller behavior from frequency analysis of the output signals and compute total harmonic distortion (THD), it can specify the more useful controlling method. The framework is modeled and fabricated by using Matlab/Simulink
Microwave Assisted Synthesis, Characterization and Biological Study of Some Chalcone Compounds Derived from Phenyl Isothiocyanate
Chalcones are synthesized by Claisen-Schmidt condensation, which involves cross-aldol condensation of appropriate aldehydes and ketones by base catalyzed reaction, the new chalcone derivatives synthesized by the reaction aldehyde with their compounds. By microwave assisted synthesis, a considerable increase in the reaction rate has been observed and that too, with better yields. M.P., TLC, CHN, FTIR, NMR and MS spectroscopy has characterized all the synthesized compounds. The biological screening data of the synthesized compounds were also studied. Keywords: microwave, chalcone, antibacterial. DOI: 10.7176/CMR/11-3-05 Publication date:March 31st 201
The 43GHz SiO maser in the circumstellar envelope of the AGB star R Cassiopeiae
We present multi-epoch, total intensity, high-resolution images of 43GHz,
v=1, J=1-0 SiO maser emission toward the Mira variable R Cas. In total we have
23 epochs of data for R Cas at approximate monthly intervals over an optical
pulsation phase range from 0.158 to 1.78. These maps show a ring-like
distribution of the maser features in a shell, which is assumed to be centred
on the star at a radius of 1.6 to 2.3 times the stellar radii. It is clear from
these images that the maser emission is significantly extended around the star.
At some epochs a faint outer arc can be seen at 2.2 stellar radii. The
intensity of the emission waxes and wanes during the stellar phase. Some maser
features are seen infalling as well as outflowing. We have made initial
comparisons of our data with models by Gray et. al. (2009).Comment: 12 pages, 14 figure
Constraining Form Factors with the Method of Unitarity Bounds
The availability of a reliable bound on an integral involving the square of
the modulus of a form factor on the unitarity cut allows one to constrain the
form factor at points inside the analyticity domain and its shape parameters,
and also to isolate domains on the real axis and in the complex energy plane
where zeros are excluded. In this lecture note, we review the mathematical
techniques of this formalism in its standard form, known as the method of
unitarity bounds, and recent developments which allow us to include information
on the phase and modulus along a part of the unitarity cut. We also provide a
brief summary of some results that we have obtained in the recent past, which
demonstrate the usefulness of the method for precision predictions on the form
factors.Comment: 12 pages, 2 figures; Lecture given at the DAE-BRNS Workshop on Hadron
Physics, Bhabha Atomic Research Centre, Mumbai, India, October 31-November 4,
2011, submitted to Proceeding
Newly Discovered RR Lyrae Stars in the SDSSXPanXSTARRS1XCatalina Footprint
We present the detection of 6,371 RR Lyrae (RRL) stars distributed across
~14,000 deg^2 of the sky from the combined data of the Sloan Digital Sky Survey
(SDSS), the Panoramic Survey Telescope and Rapid Response System 1 (PS1), and
the second photometric catalogue from the Catalina Survey (CSDR2), out of
these, ~2,021 RRL stars (~572 RRab and 1,449 RRc) are new discoveries. The RRL
stars have heliocentric distances in the 4--28 kpc distance range. RRL-like
color cuts from the SDSS and variability cuts from the PS1 are used to cull our
candidate list. We then use the CSDR2 multi-epoch data to refine our sample.
Periods were measured using the Analysis of Variance technique while the
classification process is performed with the Template Fitting Method in
addition to the visual inspection of the light curves. A cross-match of our RRL
star discoveries with previous published catalogs of RRL stars yield
completeness levels of ~50% for both RRab and RRc stars, and an efficiency of
~99% and ~87% for RRab and RRc stars, respectively. We show that our method for
selecting RRL stars allows us to recover halo structures. The full lists of all
the RRL stars are made publicly available.Comment: 14 pages, 11 figures. Accepted 2014 March 30. Received 2014 March 12;
in original form 2013 November 2
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