37,018 research outputs found
VFPred: A Fusion of Signal Processing and Machine Learning techniques in Detecting Ventricular Fibrillation from ECG Signals
Ventricular Fibrillation (VF), one of the most dangerous arrhythmias, is
responsible for sudden cardiac arrests. Thus, various algorithms have been
developed to predict VF from Electrocardiogram (ECG), which is a binary
classification problem. In the literature, we find a number of algorithms based
on signal processing, where, after some robust mathematical operations the
decision is given based on a predefined threshold over a single value. On the
other hand, some machine learning based algorithms are also reported in the
literature; however, these algorithms merely combine some parameters and make a
prediction using those as features. Both the approaches have their perks and
pitfalls; thus our motivation was to coalesce them to get the best out of the
both worlds. Hence we have developed, VFPred that, in addition to employing a
signal processing pipeline, namely, Empirical Mode Decomposition and Discrete
Time Fourier Transform for useful feature extraction, uses a Support Vector
Machine for efficient classification. VFPred turns out to be a robust algorithm
as it is able to successfully segregate the two classes with equal confidence
(Sensitivity = 99.99%, Specificity = 98.40%) even from a short signal of 5
seconds long, whereas existing works though requires longer signals, flourishes
in one but fails in the other
Quantum Nonthermal Radiation of Kerr-anti-de Sitter Black Holes
We examine the properties of Quantum nonthermal radiation of a Kerr-anti-de
Sitter (KAdS) black holes. Assuming that a crossing of the positive and
negative Dirac energy levels occurs in a region near the event horizon of the
hole, and spontaneous quantum nonthermal radiation takes place in the overlap
region. We solve the biquadratic equation governing the location of the event
horizon of the KAdS black holes and present closed analytic expression for the
radii of the horizons.Comment: 13 page
Predicting and Forecasting the Price of Constituents and Index of Cryptocurrency Using Machine Learning
At present, cryptocurrencies have become a global phenomenon in financial
sectors as it is one of the most traded financial instruments worldwide.
Cryptocurrency is not only one of the most complicated and abstruse fields
among financial instruments, but it is also deemed as a perplexing problem in
finance due to its high volatility. This paper makes an attempt to apply
machine learning techniques on the index and constituents of cryptocurrency
with a goal to predict and forecast prices thereof. In particular, the purpose
of this paper is to predict and forecast the close (closing) price of the
cryptocurrency index 30 and nine constituents of cryptocurrencies using machine
learning algorithms and models so that, it becomes easier for people to trade
these currencies. We have used several machine learning techniques and
algorithms and compared the models with each other to get the best output. We
believe that our work will help reduce the challenges and difficulties faced by
people, who invest in cryptocurrencies. Moreover, the obtained results can play
a major role in cryptocurrency portfolio management and in observing the
fluctuations in the prices of constituents of cryptocurrency market. We have
also compared our approach with similar state of the art works from the
literature, where machine learning approaches are considered for predicting and
forecasting the prices of these currencies. In the sequel, we have found that
our best approach presents better and competitive results than the best works
from the literature thereby advancing the state of the art. Using such
prediction and forecasting methods, people can easily understand the trend and
it would be even easier for them to trade in a difficult and challenging
financial instrument like cryptocurrency.Comment: main article along with the supplement article at the en
Waves in General Relativistic Two-fluid Plasma around a Schwarzschild Black Hole
Waves propagating in the relativistic electron-positron or ions plasma are
investigated in a frame of two-fluid equations using the 3+1 formalism of
general relativity developed by Thorne, Price and Macdonald (TPM). The plasma
is assumed to be freefalling in the radial direction toward the event horizon
due to the strong gravitational field of a Schwarzschild black hole. The local
dispersion relations for transverse and longitudinal waves have been derived,
in analogy with the special relativistic formulation as explained in an earlier
paper, to take account of relativistic effects due to the event horizon using
WKB approximationComment: 7 pages; Astrophys Space Sci (2012). arXiv admin note: substantial
text overlap with arXiv:1008.483
New universality class in percolation on multifractal scale-free planar stochastic lattice
We investigate site percolation on a weighted planar stochastic lattice
(WPSL) which is a multifractal and whose dual is a scale-free network.
Percolation is typically characterized by percolation threshold and by a
set of critical exponents , , which describe the critical
behavior of percolation probability , mean cluster size
and the correlation length .
Besides, the exponent characterizes the cluster size distribution
function and the fractal dimension the spanning
cluster. We obtain an exact value for and for all these exponents. Our
results suggest that the percolation on WPSL belong to a new universality class
as its exponents do not share the same value as for all the existing planar
lattices.Comment: 5 pages, 5 figure
Universality class of site and bond percolation on multi-multifractal scale-free planar stochastic lattice
In this article, we investigate both site and bond percolation on a weighted
planar stochastic lattice (WPSL) which is a multi-multifractal and whose dual
is a scale-free network. The characteristic properties of percolation is that
it exhibits threshold phenomena as we find sudden or abrupt jump in spanning
probability across accompanied by the divergence of some other observable
quantities which is reminiscent of continuous phase transition. Indeed,
percolation is characterized by the critical behavior of percolation strength
, mean cluster size and the
system size which are known as the equivalent
counterpart of the order parameter, susceptibility and correlation length
respectively. Moreover, the cluster size distribution function and the mass-length relation of the spanning cluster
also provide useful characterization of the percolation process. We obtain an
exact value for and for all the exponents such as and . We find that, except , all the exponents are exactly the
same in both bond and site percolation despite the significant difference in
the definition of cluster and other quantities. Our results suggest that the
percolation on WPSL belongs to a new universality class as its exponents do not
share the same value as for all the existing planar lattices and like other
cases its site and bond belong to the same universality class.Comment: 12 pages, 7 figures, 1 tabl
Intrinsic Cutoff and Acausality for Massive Spin 2 Fields Coupled to Electromagnetism
We couple a massive spin 2 particle to electromagnetism. By introducing new,
redundant degrees of freedom using the Stueckelberg formalism, we extract an
intrinsic, model independent UV cutoff of the effective field theory describing
this system. The cutoff signals both the onset of a strongly interacting
dynamical regime and a finite size for the spin 2 particle. We show that the
existence of a cutoff is strictly connected to other pathologies of interacting
high-spin fields, such as the Velo-Zwanziger acausality. We also briefly
comment on implications of this result for the detection of high spin states
and on its possible generalization to arbitrary spin.Comment: 14 pages, to appear in Nuclear Physics
A Noble Methodology for Users Work Process Driven Software Requirements for Smart Handheld Devices
Requirement engineering is a key ingredient for software development to be
effective. Apart from the traditional software requirement which is not much
appropriate for new emerging software such as smart handheld device based
software. In many perspectives of requirement engineering, traditional and new
emerging software are not similar. Whereas requirement engineering of
traditional software needs more research, it is obvious that new emerging
software needs methodically and in-depth research for improved productivity,
quality, risk management and validity. In particular, the result of this paper
shows that how effective requirement engineering can improve in project
negotiation, project planning, managing feature creep, testing, defect, rework
and product quality. This paper also shows a new methodology which is focused
on users work process applicable for eliciting the requirement of traditional
software and any new type software of smart handheld device such as iPad. As an
example, the paper shows how the methodology will be applied as a software
requirement of iPad-based software for play-group students.Comment: 18 pages, 9 figure
Microcomputer Aided Selection Of Robot Manipulators
This paper presents two programs for microcomputer aided assessment of the
performance of robot manipulators. The first program automatically generates
robot models based on user-supplied kinematic parameters. The program also
derives a kinematic model that relates the motion of manipulator end-effector to
the motion of the joints using the inverse kinematic approach. The approach uses a
robust inversion technique that can handle singular conditions as well as joint
redundancy. A user can optionally select evaluation of kinematic capabilities of the
robot manipulator, such as the ability of the end-effector to reach a specified
position and orientation in space or the evaluation of the work space. The second
program generates dynamic variables, such as forces and torques, based on
user-supplied dynamic parameters and equations of motion of the various joints.
Both programs are written for implementation on personal computers. Several
runs were carried out to demonstrate the capability and execution times of the two
program
Modulational instability, rogue waves, and envelope solitons in opposite polarity dusty plasmas
Dust-acoustic (DA) waves (DAWs) and their modulational instability (MI) have
been investigated theoretically in a plasma system consisting of inertial
opposite polarity (positively and negatively) warm adiabatic charged dust
particles as well as inertialess non-extensive -distributed electrons and
non-thermal ions. A nonlinear Schr\"{o}dinger (NLS) equation is derived by
using the reductive perturbation method. It has been observed from the analysis
of NLS equaion that the modulationally stable solitary DAWs give rise to the
existence of dark envelope solitons, and that the modulationally unstable
solitary DAWs give rise to the existence of bright envelope solitons or rogue
structures. It is also observed for the fast mode of DAWs that the basic
features (viz. stability of the DAWs, MI growth rate, amplitude and width of
the DA rogue waves, etc.) are significantly modified by the related plasma
parameters (viz. dust masses, dust charge state, non-extensive parameter ,
and non-thermal parameter ). The results of our present investigation
might be useful for understanding different nonlinear electrostatic phenomena
in both space (viz. ionosphere and mesosphere) and laboratory plasmas (viz.
high intensity laser irradiation and hot cathode discharge).Comment: 11 pages; 11 figure
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