5,261 research outputs found
DEVELOPMENT OF SIMPLIFIED METHOD OF ESTIMATION OF DEFORMATION PROCESSING OF CENTRAL ZONES OF ROLLOUT SECTION FROM CONTINUOUS COLLECTION IN ROLLING IN CALIBERS
Development of a simplified method of estimation of deformation
processing of central zones of rollout section from continuous collection in rolling in
calibers
Detection of Giant Radio Pulses from the Pulsar PSR B0656+14
Giant pulses (GPs) have been detected from the pulsar PSR B0656+14. A pulse
that is more intense than the average pulse by a factor of 120 is encountered
approximately once in 3000 observed periods of the pulsar. The peak flux
density of the strongest pulse, 120 Jy, is a factor of 630 higher than that of
the average pulse. The GP energy exceeds the energy of the average pulse by up
to a factor of 110, which is comparable to that for other known pulsars with
GPs, including the Crab pulsar and the millisecond pulsar PSR B1937+21. The
giant pulses are a factor of 6 narrower than the average pulse and are
clustered at the head of the average pulse. PSR B0656+14 along with PSR
B0031-07, PSR B1112+50, and PSR J1752+2359 belong to a group of pulsars that
differ from previously known ones in which GPs have been detected without any
extremely strong magnetic field on the light cylinder.Comment: 10 pages, 3 figures, 1 table; originally published in Russian in
Pis'ma Astron. Zh., 2006, v.32, 650; translated by George Rudnitskii; the
English version will be appear in Astronomy Letter
Advanced Hough-based method for on-device document localization
The demand for on-device document recognition systems increases in
conjunction with the emergence of more strict privacy and security
requirements. In such systems, there is no data transfer from the end device to
a third-party information processing servers. The response time is vital to the
user experience of on-device document recognition. Combined with the
unavailability of discrete GPUs, powerful CPUs, or a large RAM capacity on
consumer-grade end devices such as smartphones, the time limitations put
significant constraints on the computational complexity of the applied
algorithms for on-device execution.
In this work, we consider document location in an image without prior
knowledge of the document content or its internal structure. In accordance with
the published works, at least 5 systems offer solutions for on-device document
location. All these systems use a location method which can be considered
Hough-based. The precision of such systems seems to be lower than that of the
state-of-the-art solutions which were not designed to account for the limited
computational resources.
We propose an advanced Hough-based method. In contrast with other approaches,
it accounts for the geometric invariants of the central projection model and
combines both edge and color features for document boundary detection. The
proposed method allowed for the second best result for SmartDoc dataset in
terms of precision, surpassed by U-net like neural network. When evaluated on a
more challenging MIDV-500 dataset, the proposed algorithm guaranteed the best
precision compared to published methods. Our method retained the applicability
to on-device computations.Comment: This is a preprint of the article submitted for publication in the
journal "Computer Optics
Detection of Giant Pulses from the Pulsar PSR B0031-07
Giant pulses have been detected from the pulsar PSR B0031-07. A pulse with an
intensity higher than the intensity of the average pulse by a factor of 50 or
more is encountered approximately once per 300 observed periods. The peak flux
density of the strongest pulse is 530 Jy, which is a factor of 120 higher than
the peak flux density of the average pulse. The giant pulses are a factor of 20
narrower than the integrated profile and are clustered about its center.Comment: 7 pages, 2 figures, to appear in: Pis'ma v Astronomicheskii Zhurnal,
2004, v.30, No.4, and will be translated as: Astronomy Letters, v.30, No.
Instantaneous Radio Spectra of Giant Pulses from the Crab Pulsar from Decimeter to Decameter Wavelengths
The results of simultaneous multifrequency observations of giant radio pulses
from the Crab pulsar, PSR B0531+21, at 23, 111, and 600 MHz are presented and
analyzed. Giant pulses were detected at a frequency as low as 23 MHz for the
first time. Of the 45 giant pulses detected at 23 MHz, 12 were identified with
counterparts observed simultaneously at 600 MHz. Of the 128 giant pulses
detected at 111 MHz, 21 were identified with counterparts observed
simultaneously at 600 MHz. The spectral indices for the power-law frequency
dependence of the giant-pulse energies are from -3.1 to -1.6. The mean spectral
index is -2.7 +/- 0.1 and is the same for both frequency combinations (600-111
MHz and 600-23 MHz). The large scatter in the spectral indices of the
individual pulses and the large number of unidentified giant pulses suggest
that the spectra of the individual giant pulses do not actually follow a simple
power law. The observed shapes of the giant pulses at all three frequencies are
determined by scattering on interstellar plasma irregularities. The scatter
broadening of the pulses and its frequency dependence were determined as
tau_sc=20*(f/100)^(-3.5 +/- 0.1) ms, where the frequency f is in MHz.Comment: 13 pages, 1 figure, 1 table (originally published in Russian in
Astronomicheskii Zhurnal, 2006, vol. 83, No. 7, pp. 630-637), translated by
Georgii Rudnitski
Deformation of an Elastic Spherical Shell under the Pressure of Viscous Incompressible Fluid
The deformation of an elastic spherical shell under the pressure of viscous incompressible fluid is considered. Analytical formulas for calculating the components of normal and tangential deflections of the shell middle surface are obtained. A new mathematical model of an elastic spherical shell is offered on the basis of introduction of the Finite Element Method calculations. The comparison of the asymptotic and numerical results is performed
Porous matrixes based on ion-irradiated polymer as templates for synthesis of nanowires
Irradiation with swift heavy ions is usually used for production of track membranes
(nuclear filters). These membranes traditionally used as filters for fine filtration
in medicine and biology.
Another application is matrixes for so called matrix synthesis. The idea of this
technique is to fill pores by any desired material- metal,polymer, semiconductor and so
on.
This work is devoted to formation of membrane for template synthesis, to investigation
of filling process and to study some properties of obtained structures.
It was found that filtration track membranes are not the best material for template
synthesis –another type of matrixes are needed- with different pores profiles and parallel
pores orientation These parameters could be obtained during irradiation. Different
types of etching gave possibility to vary by will the shape of the pores and to obtain
pores with conical shape. The process of etching in the alkali solution in mixture of
water and alcohol was investigated.
The main part of the work devoted to fabrication of micro- and nanowires via electrodeposition.
Different types of metals-copper, silver, cobalt and nickel were used for
galvanic deposition of the pores. Two types of the processes- galvanostatic and potentiostatic
were investigated.
It was also demonstrated that obtained metallic nanowires could be used as the
substrates for deposition of the probe (biological molecules) in mass-spectrometer.
The application of such structures in non-linear optic was also described.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2083
On the susceptibility function of piecewise expanding interval maps
We study the susceptibility function Psi(z) associated to the perturbation
f_t=f+tX of a piecewise expanding interval map f. The analysis is based on a
spectral description of transfer operators. It gives in particular sufficient
conditions which guarantee that Psi(z) is holomorphic in a disc of larger than
one. Although Psi(1) is the formal derivative of the SRB measure of f_t with
respect to t, we present examples satisfying our conditions so that the SRB
measure is not Lipschitz.*We propose a new version of Ruelle's conjectures.* In
v2, we corrected a few minor mistakes and added Conjectures A-B and Remark 4.5.
In v3, we corrected the perturbation (X(f(x)) instead of X(x)), in particular
in the examples from Section 6. As a consequence, Psi(z) has a pole at z=1 for
these examples.Comment: To appear Comm. Math. Phy
QUANTITATIVE ESTIMATES OF DIRECT PYROGENIC CARBON EMISSIONS IN FORESTS OF RUSSIA ACCORDING TO REMOTE MONITORING DATA 2021
This paper presents the statistics of direct wildfire carbon emission estimates during the wildfires of 2021 on forest lands of Russia using long-term satellite data. In 2021, the area affected by forest wildfires was 9.3 million ha, while carbon emissions amounted to 66.4 MtC. Said values are almost two points higher than the long-term average values. A comparison of similar indicators for twenty years allowed us to conclude that said year was anomalous with respect to the entire time series, similar to the wildfire seasons of 2003 and 2012. A period or interval for recurrence of three anomalous wildfire seasons is nine years. The reason for the recurrence of anomalous wildfire seasons is yet to be found. At the same time, the forest areas affected by wildfires, and direct carbon and other greenhouse gas emissions in anomalous wildfire years decreased from 127.2 MtC (3.7 times) in 2003 to 83.8 MtC (2.4 times) in 2012, and to 66.4 MtC (1.9 times) in 2021
Excitations in the Halo Nucleus He-6 Following The Li-7(gamma,p)He-6 Reaction
A broad excited state was observed in 6-He with energy E_x = 5 +/- 1 MeV and
width Gamma = 3 +/- 1 MeV, following the reaction Li-7(gamma,p)He-6. The state
is consistent with a number of broad resonances predicted by recent cluster
model calculations. The well-established reaction mechanism, combined with a
simple and transparent analysis procedure confers considerable validity to this
observation.Comment: 3 pages of LaTeX, 3 figures in PostScript, approved for publication
in Phys. Rev. C, August, 200
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