9,091 research outputs found
Digital Demodulator for BFSK waveform based upon Correlator and Differentiator Systems
The present article relates in general to digital demodulation of Binary Frequency Shift Keying (BFSK waveform) . New processing methods for demodulating the BFSK-signals are proposed here. Based on Sampler Correlator, the hardware consumption for the proposed techniques is reduced in comparison with other reported. Theoretical details concerning limits of applicability are also given by closed-form expressions. Simulation experiments are illustrated to validate the overall performance
Fractional Newton-Raphson Method Accelerated with Aitken's Method
The Newton-Raphson (N-R) method is characterized by the fact that generating
a divergent sequence can lead to the creation of a fractal, on the other hand
the order of the fractional derivatives seems to be closely related to the
fractal dimension, based on the above, a method was developed that makes use of
the N-R method and the fractional derivative of Riemann-Liouville (R-L) that
has been named as the Fractional Newton-Raphson (F N-R) method.
In the following work we present a way to obtain the convergence of the F N-R
method, which seems to be at least linearly convergent for the case where the
order of the derivative is different from one, a simplified way to
construct the fractional derivative and fractional integral operators of R-L is
presented, an introduction to the Aitken's method is made and it is explained
why it has the capacity to accelerate the convergence of iterative methods to
finally present the results that were obtained when implementing the Aitken's
method in F N-R method.Comment: Newton-Raphson Method, Fractional Calculus, Fractional Derivative of
Riemann-Liouville, Method of Aitken. arXiv admin note: substantial text
overlap with arXiv:1710.0763
Short-term synaptic facilitation improves information retrieval in noisy neural networks
Short-term synaptic depression and facilitation have been found to greatly
influence the performance of autoassociative neural networks. However, only
partial results, focused for instance on the computation of the maximum storage
capacity at zero temperature, have been obtained to date. In this work, we
extended the study of the effect of these synaptic mechanisms on
autoassociative neural networks to more realistic and general conditions,
including the presence of noise in the system. In particular, we characterized
the behavior of the system by means of its phase diagrams, and we concluded
that synaptic facilitation significantly enlarges the region of good retrieval
performance of the network. We also found that networks with facilitating
synapses may have critical temperatures substantially higher than those of
standard autoassociative networks, thus allowing neural networks to perform
better under high-noise conditions.Comment: 6 pages, 3 figures, to appear in EP
Tunneling Splittings in Mn12-Acetate Single Crystals
A Landau-Zener multi-crossing method has been used to investigate the tunnel
splittings in high quality Mn-acetate single crystals in the pure
quantum relaxation regime and for fields applied parallel to the magnetic easy
axis. With this method several individual tunneling resonances have been
studied over a broad range of time scales. The relaxation is found to be
non-exponential and a distribution of tunnel splittings is inferred from the
data. The distributions suggest that the inhomogeneity in the tunneling rates
is due to disorder that produces a non-zero mean value of the average
transverse anisotropy, such as in a solvent disorder model. Further, the effect
of intermolecular dipolar interaction on the magnetic relaxation has been
studied.Comment: Europhysics Letters (in press). 7 pages, including 3 figure
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