86 research outputs found
The sentiment-analysis algorithm of social networks text resources based on ontology
In this paper the features of semantic and sentiment analysis of textual data of social
networks are presented, and an original model and algorithm for sentiment analysis of textual
fragments of social networks using fuzzy linguistic ontology are proposed. This approach
involves the use of various subgraphs of fuzzy ontology when considering texts of various
subject areas with regard to contexts. In addition, the algorithm involves the assessment of the
sentiment scores of individual syntagmatic structures into which the analyzed text fragments
are divided. It also presents the results of experiments comparing the efficiency of the
developed algorithm with a group of existing approaches in analyzing text fragments on the
example of data from the social network VKontakte
Interplay between single-particle and two-particle tunneling in normal metal-d-wave superconductor junctions probed by shot noise
We discuss how life-time broadening of quasiparticle states influences
single- and two-particle current transport through zero-energy states at normal
metal/d-wave superconductor junctions. We distinguish between intrinsic
broadening (imaginary part of the energy), which couples the bound
states with the superconducting reservoir, and broadening due to leakage
through the junction barrier, which couples the bound states with the normal
metal reservoir. We show that shot noise is highly sensitive to the mechanism
of broadening, while the conductance is not. In the limit of small but finite
intrinsic broadening, compared to the junction transparency ,
, the low-voltage shot noise at zero frequency and zero
temperature becomes proportional to the magnitude of intrinsic
broadening ( is the maximum d-wave gap).Comment: 6 pages, 4 figures; presented at the SDP2001 conference in Toky
Hard pomeron enhancement of ultrahigh-energy neutrino-nucleon cross-sections
An unknown small-x behavior of nucleon structure functions gives appreciable
uncertainties to high-energy neutrino-nucleon cross-sections. We construct
structure functions using at small x Regge inspired description by A. Donnachie
and P. V. Landshoff with soft and hard pomerons, and employing at larger x the
perturbative QCD expressions. The smooth interpolation between two regimes for
each Q^2 is provided with the help of simple polynomial functions. To obtain
low-x neutrino-nucleon structure functions and
singlet part of from Donnachie-Landshoff
function , we use the Q^2-dependent ratios R_2(Q^2) and
R_3(Q^2) derived from perturbative QCD calculations. Non-singlet part of F_3 at
low x, which is very small, is taken as power-law extrapolation of perturbative
function at larger x. This procedure gives a full set of smooth
neutrino-nucleon structure functions in the whole range of x and Q^2 at
interest.
Using these structure functions, we have calculated the neutrino-nucleon
cross-sections and compared them with some other cross-sections known in
literature. Our cross-sections turn out to be the highest among them at the
highest energies, which is explained by contribution of the hard pomeron.Comment: Final revised version, accepted by Phys. Rev. D; 18 pages, 7 figure
Supercurrents through gated superconductor-normal-metal-superconductor contacts: the Josephson-transistor
We analyze the transport through a narrow ballistic superconductor-normal-
metal-superconductor Josephson contact with non-ideal transmission at the
superconductor-normal-metal interfaces, e.g., due to insulating layers,
effective mass steps, or band misfits (SIN interfaces). The electronic spectrum
in the normal wire is determined through the combination of Andreev- and normal
reflection at the SIN interfaces. Strong normal scattering at the SIN
interfaces introduces electron- and hole-like resonances in the normal region
which show up in the quasi-particle spectrum. These resonances have strong
implications for the critical supercurrent which we find to be determined
by the lowest quasi-particle level: tuning the potential to the
points where electron- and hole-like resonances cross, we find sharp peaks in
, resulting in a transitor effect. We compare the performance of
this Resonant Josephson-Transistor (RJT) with that of a Superconducting Single
Electron Transistor (SSET).Comment: to appear in PRB, 11 pages, 9 figure
Nonequilibrium Josephson effect in mesoscopic ballistic multiterminal SNS junctions
We present a detailed study of nonequilibrium Josephson currents and
conductance in ballistic multiterminal SNS-devices. Nonequilibrium is created
by means of quasiparticle injection from a normal reservoir connected to the
normal part of the junction. By applying a voltage at the normal reservoir the
Josephson current can be suppressed or the direction of the current can be
reversed. For a junction longer than the thermal length, , the
nonequilibrium current increases linearly with applied voltage, saturating at a
value equal to the equilibrium current of a short junction. The conductance
exhibits a finite bias anomaly around . For symmetric
injection, the conductance oscillates -periodically with the phase
difference between the superconductors, with position of the minimum
( or ) dependent on applied voltage and temperature. For
asymmetric injection, both the nonequilibrium Josephson current and the
conductance becomes -periodic in phase difference. Inclusion of barriers
at the NS-interfaces gives rise to a resonant behavior of the total Josephson
current with respect to junction length with a period . Both
three and four terminal junctions are studied.Comment: 21 pages, 19 figures, submitted to Phys. Rev.
Surface state atoms and their contribution to the surface tension of quantum liquids
We investigate the new type of excitations on the surface of liquid helium.
These excitations, called surfons, appear because helium atoms have discrete
energy level at the liquid surface, being attracted to the surface by the van
der Waals force and repulsed at a hard-core interatomic distance. The
concentration of the surfons increases with temperature. The surfons propagate
along the surface and form a two-dimensional gas. Basing on the simple model of
the surfon microscopic structure, we estimate the surfon activation energy and
effective mass for both helium isotopes. We also calculate the contribution of
the surfons to the temperature dependence of the surface tension. This
contribution explains the great and long-standing discrepancy between theory
and experiment on this temperature dependence in both helium isotopes. The
achieved agreement between our theory and experiment is extremely high. The
comparison with experiment allows to extract the surfon activation energy and
effective mass. The values of these surfon microscopic parameters are in a
reasonable agreement with the calculated from the proposed simple model of
surfon structure.Comment: 10 pages, 6 figure
Morphogenetic analysis of Helix pomatia L. (Pulmonata, Helicidae) populations from south-eastern and eastern parts of the modern area
Relativistic superfluid models for rotating neutron stars
This article starts by providing an introductory overview of the theoretical
mechanics of rotating neutron stars as developped to account for the frequency
variations, and particularly the discontinuous glitches, observed in pulsars.
The theory suggests, and the observations seem to confirm, that an essential
role is played by the interaction between the solid crust and inner layers
whose superfluid nature allows them to rotate independently. However many
significant details remain to be clarified, even in much studied cases such as
the Crab and Vela. The second part of this article is more technical,
concentrating on just one of the many physical aspects that needs further
development, namely the provision of a satisfactorily relativistic (local but
not microscopic) treatment of the effects of the neutron superfluidity that is
involved.Comment: 42 pages LateX. Contribution to Physics of Neutron Star Interiors,
ed. D. Blasche, N.K. Glendenning, A. Sedrakian (ECT workshop, Trento, June
2000
Total Cross Section Measurements With π- , Σ- And Protons On Nuclei And Nucleons Around 600 Gev/c
Total cross sections for Σ- and π- on beryllium, carbon, polyethylene and copper as well as total cross sections for protons on beryllium and carbon have been measured in a broad momentum range around 600GeV/c . These measurements were performed with a transmission technique in the SELEX hyperon-beam experiment at Fermilab. We report on results obtained for hadron-nucleus cross sections and on results for σtot(Σ-N) and σtot(π-N) , which were deduced from nuclear cross sections. © 2000 Elsevier Science B.V.57901/02/15277312Langland, J.L., (1995) Ph.D. Thesis, , University of IowaKleinfelder, S.A., (1988) IEEE Trans. Nucl. Sci., 35 (1)Dersch, U., (1998) Ph.D. Thesis, HeidelbergBiagi, S.F., (1981) Nucl. Phys. B, 186, pp. 1-21Bellettini, G., (1966) Nucl. Phys., 79, pp. 609-624Schiz, A.M., (1980) Phys. Rev. D, 21, pp. 3010-3022Murthy, P.V.R., (1975) Nucl. Phys. B, 92, pp. 269-308Caso, C., (1998) Eur. Phys. J. C, 3. , http://pdg.lbl.gov/1998/contents_plots.html, and data on total cross sections from computer readable filesSchiz, A.M., (1979) Ph.D. Thesis, , Yale University(1973) Landolt Börnstein Tables, 7. , Springer editionEngler, J., (1970) Phys. Lett. B, 32, pp. 716-719Babaev, A., (1974) Phys. Lett. B, 51, pp. 501-504Glauber, R.J., (1959) Boulder Lectures, pp. 315-413Franco, V., (1972) Phys. Rev. C, 6, pp. 748-757Karmanov, V.A., Kondratyuk, L.A., (1973) JETP Lett., 18, pp. 266-268Burq, J.P., (1983) Nucl. Phys. B, 217, pp. 285-335Gross, D., (1978) Phys. Rev. Lett., 41, pp. 217-220Beznogikh, G.G., (1972) Phys. Lett. B, 39, pp. 411-413Vorobyov, A.A., (1972) Phys. Lett. B, 41, pp. 639-641Foley, K.J., (1967) Phys. Rev. Lett., 19, pp. 857-859Fajardo, L.A., (1981) Phys. Rev. D, 24, pp. 46-65Jenni, P., (1977) Nucl. Phys. B, 129, pp. 232-252Breedon, R.E., (1989) Phys. Rev. Lett. B, 216, pp. 459-465Amos, N., (1983) Phys. Rev. Lett. B, 128, pp. 343-348Amaldi, U., (1977) Phys. Rev. Lett. B, 66, pp. 390-394Amos, N., (1985) Nucl. Phys. B, 262, pp. 689-714Akopin, V.D., (1977) Sov. J. Nucl. Phys., 25, pp. 51-55Amirkhanov, I.V., (1973) Sov. J. Nucl. Phys., 17, pp. 636-637Foley, K.J., (1969) Phys. Rev., 181, pp. 1775-1793Apokin, V.D., (1976) Nucl. Phys. B, 106, pp. 413-429Burq, J.P., (1982) Phys. Lett. B, 109, pp. 124-127Dakhno, L.G., (1983) Sov. J. Nucl. Phys., 37, pp. 590-598Kazarinov, M., (1976) Sov. Phys. JETP, 43, pp. 598-606De Jager, C.W., (1974) At. Data Nucl. Data Tables, 14, pp. 479-508Donnachie, A., Landshoff, P.V., (1992) Phys. Lett. B, 296, pp. 227-232Lipkin, H., (1975) Phys. Rev. D, 11, pp. 1827-1831Barnett, R.M., (1996) Phys. Rev. D, 54, pp. 191-192Carroll, A.S., (1979) Phys. Lett. B, 80, pp. 423-427Badier, J., (1972) Phys. Lett. B, 41, pp. 387-39
Total Cross Section Measurements with pi-, Sigma- and Protons on Nuclei and Nucleons around 600 GeV/c
Total cross sections for Sigma- and pi- on beryllium, carbon, polyethylene
and copper as well as total cross sections for protons on beryllium and carbon
have been measured in a broad momentum range around 600GeV/c. These
measurements were performed with a transmission technique adapted to the SELEX
hyperon-beam experiment at Fermilab. We report on results obtained for
hadron-nucleus cross sections and on results for sigma_tot(Sigma- N) and
sigma_tot(pi- N), which were deduced from nuclear cross sections.Comment: 42 pages, submitted to Nucl.Phys.
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