2,596 research outputs found
Fission barriers heights in A 200 mass region
Statistical model analysis has been carried out for and induced
fission reactions using a consistent description for fission barrier and level
density in A 200 mass region. A continuous damping of shell correction
with excitation energy have been considered. Extracted fission barriers agree
well with the recent microscopic-macroscopic model. The shell corrections at
the saddle point were found to be not significant.Comment: Pramana - J. Phys. (In press
Gaussian information matrix for Wiener model identification
We present a closed form expression for the information matrix associated
with the Wiener model identification problem under the assumption that the
input signal is a stationary Gaussian process. This expression holds under
quite generic assumptions. We allow the linear sub-system to have a rational
transfer function of arbitrary order, and the static nonlinearity to be a
polynomial of arbitrary degree. We also present a simple expression for the
determinant of the information matrix. The expressions presented herein has
been used for optimal experiment design for Wiener model identification.Comment: 16 page
Dynamical system analysis for DBI dark energy interacting with dark matter
A dynamical system analysis related to Dirac Born Infeld (DBI) cosmological
model has been investigated in this present work. For spatially flat FRW space
time, the Einstein field equation for DBI scenario has been used to study the
dynamics of DBI dark energy interacting with dark matter. The DBI dark energy
model is considered as a scalar field with a nonstandard kinetic energy term.
An interaction between the DBI dark energy and dark matter is considered
through a phenomenological interaction between DBI scalar field and the dark
matter fluid. The field equations are reduced to an autonomous dynamical system
by a suitable redefinition of the basic variables. The potential of the DBI
scalar field is assumed to be exponential. Finally, critical points are
determined, their nature have been analyzed and corresponding cosmological
scenario has been discussed.Comment: 12 pages, 9 figure
Dilatonic Scalar Field: A Dynamical System Analysis
The work deals with homogeneous and isotropic, flat FRW model of the universe
which is filled up with non-interacting dark matter and dark energy to
compatible with recent observational evidences. By choosing the dark energy in
the form of a dilatonic scalar field, the evolution equations are reduced to an
autonomous system. A phase space analysis is done around the critical points
and stability criteria is examined. Finally, cosmological implications of the
nature of the critical points are discussed.Comment: 8 pages, 4 figure
A Dynamical System Analysis of Holographic Dark Energy Models with Different IR Cutoff
The paper deals with a dynamical system analysis of the cosmological
evolution of an holographic dark energy (HDE) model interacting with dark
matter (DM) which is chosen in the form of dust. The infrared cut-off of the
holographic model is chosen as future event horizon or Ricci length scale. The
interaction term between dark energy and dark matter is chosen of following
three types i) proportional to the sum of the energy densities of the two dark
components ii) proportional to the product of the matter energy densities and
iii) proportional to dark energy density. The dynamical equations are reduced
to an autonomous system for the three cases and corresponding phase space is
analyzed.Comment: 13 pages, 9 figure
Dynamical System Analysis for a phantom model
The paper deals with a dynamical system analysis related to phantom
cosmological model . Here gravity is coupled to phantom scalar field having
scalar coupling function and a potential. The field equations are reduced to an
autonomous dynamical system by a suitable redefinition of the basic variables
and assuming some suitable form of the potential function. Finally, critical
points are evaluated, their nature have been analyzed and corresponding
cosmological scenario has been discussed.Comment: 15 pages, 3 figure
A Dynamical System Analysis of Three Fluid cosmological Model
In Friedman-Robertson-Walker flat spacetime, we consider a three fluid
cosmological model which contains dark matter, dark energy and baryonic matter
in the form of perfect fluid with a barotropic equation of state. Dark matter
is taken in form of dust and dark energy is described by a scalar field with a
potential . Einstein's field equations are reduced to an autonomous
dynamical system by suitable redefinition of basic variables. Considering
exponential potential for the scalar field, critical points are obtained for
the autonomous system. Finally stability of the critical points and
cosmological implications are analyzed.Comment: 10 pages, 7 figure
Zadoff-Chu sequence design for random access initial uplink synchronization
The autocorrelation of a Zadoff-Chu (ZC) sequence with a non-zero cyclically
shifted version of itself is zero. Due to the interesting property, ZC
sequences are widely used in the LTE air interface in the primary
synchronization signal (PSS), random access preamble (PRACH), uplink control
channel (PUCCH) etc. However, this interesting property of ZC sequence is not
useful in the random access initial uplink synchronization problem due to some
specific structures of the underlying problem. In particular, the state of the
art uplink synchronization algorithms do not perform equally for all ZC
sequences. In this work, we show a systematic procedure to choose the ZC
sequences that yield the optimum performance of the uplink synchronization
algorithms. At first, we show that the uplink synchronization is a sparse
signal recovery problem on an overcomplete basis. Next, we use the theory of
sparse recovery algorithms and identify a factor that controls performance of
the algorithms. We then suggest a ZC sequence design procedure to optimally
choose this factor. The simulation results show that the performance of most of
the state of the art uplink synchronization algorithms improve significantly
when the ZC sequences are chosen by using the proposed technique.Comment: 13 pages, 7 figure
InfyNLP at SMM4H Task 2: Stacked Ensemble of Shallow Convolutional Neural Networks for Identifying Personal Medication Intake from Twitter
This paper describes Infosys's participation in the "2nd Social Media Mining
for Health Applications Shared Task at AMIA, 2017, Task 2". Mining social media
messages for health and drug related information has received significant
interest in pharmacovigilance research. This task targets at developing
automated classification models for identifying tweets containing descriptions
of personal intake of medicines. Towards this objective we train a stacked
ensemble of shallow convolutional neural network (CNN) models on an annotated
dataset provided by the organizers. We use random search for tuning the
hyper-parameters of the CNN and submit an ensemble of best models for the
prediction task. Our system secured first place among 9 teams, with a
micro-averaged F-score of 0.693.Comment: 2nd Workshop on Social Media Mining for Healt
Synchronization, phase slips and coherent structures in area-preserving maps
The problem of synchronization of coupled Hamiltonian systems exhibits
interesting features due to the non-uniform or mixed nature (regular and
chaotic) of the phase space. We study these features by investigating the
synchronization of unidirectionally coupled area-preserving maps coupled by the
Pecora-Carroll method. We find that coupled standard maps show complete
synchronization for values of the nonlinearity parameter at which regular
structures are still present in phase space. The distribution of
synchronization times has a power law tail indicating long synchronization
times for at least some of the synchronizing trajectories. With the
introduction of coherent structures using parameter perturbation in the system,
this distribution crosses over to exponential behavior, indicating shorter
synchronization times, and the number of initial conditions which synchronize
increases significantly, indicating an enhancement in the basin of
synchronization. On the other hand, coupled blinking vortex maps display both
phase synchronization and phase slips, depending on the location of the initial
conditions. We discuss the implication of our results.Comment: 15 pages, 10 figures, Perspectives in Nonlinear Dynamics 2016 (24th -
29th July 2016), Berlin, Germany. The paper is a part of the proceedings to
appear in Pramana - Journal of Physics (Indian Academy of Sciences);
distributed in print outside India and online worldwide by Springe
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