563 research outputs found

    Метод оптимизации ярусно-параллельной формы представления задачи для реконфигурируемых вычислительных систем

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    В роботі запропонований метод оптимізації структури графа задачі, поданого в ярусно-паралельній формі, що враховує вимоги мінімізації часу виконання задачі та обмеження апаратних ресурсів, та дозволяє підвищити продуктивність реконфігурованих обчислювальних систем.The method of optimizing the structure of the task graph represented by a macro dataflow graph, is proposed. The method takes into account the requirement to minimize execution time and the limitations of hardware resources. The method improves the performance of reconfigurable computing systems.В статье предложен метод оптимизации структуры графа задачи, представленного в ярусно-параллельной форме, который учитывает требования минимизации времени выполнения задачи, ограничения аппаратных ресурсов и позволяет повысить производительность реконфигурируемых вычислительных систем

    Dual circuit radio frequency identification system of animals

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    У роботі проаналізовано вплив технічних і біологічних факторів на ефективність роботи систем радіоідентифікації великої рогатої худоби при використанні рідерів з рамковими антенами. Встановлено, що у таких системах достовірність читання кодів транспондерів у значній мірі залежить від відстані і взаємоорієнтації антен транспондерів і рідерів. Для підвищення достовірності читання кодів транспондерів запропоновано використовувати конструктив проходу тварин у якості двоконтурної просторової антени, що індуктивно пов'язана з антеною рідера.This is analyzed the influence of technical and biological factors on the performance of radioidentification systems of cattle by using readers with loop antennas. It is found that the reliability of of reading transponders codes largely depends on the distance and interaction orientation of antennas and transponder readers. To improve the reliability of reading the transponder codes is suggested to use the constructive passage of animals as a twodimensional antenna which inductively is connected with the antenna reade

    Diamagnetism above Tc in underdoped Bi2.2Sr1.8Ca2Cu3O10+d

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    Single crystals of Bi2+xSr2xCa2Cu3O10+δ{\rm Bi}_{2+x}{\rm Sr}_{2-x}{\rm Ca}_{2}{\rm Cu}_{3}{\rm O}_{10+\delta}(Bi2223) with x=0.2x=0.2 were grown by a traveling solvent floating zone method in order to investigate the superconducting properties of highly underdoped Bi2223.Grown crystals were characterized by X-ray diffraction, DC susceptibility and resistivity measurements, confirming Bi2223 to be the main phase.The crystals were annealed under various oxygen partial pressures to adjust their carrier densities from optimally doped to highly underdoped.The fluctuation diamagnetic component above the superconducting transition temperature TcT_{\rm c} extracted from the anisotropic normal state susceptibilities χab(T)\chi_{ab}(T) (HcH\perp c) and χc(T)\chi_{c}(T) (HcH\parallel c) was found to increase with underdoping, suggesting a decrease in the superconducting dimensionality and/or increase in the fluctuating vortex liquid region.Comment: 6 pages, 7 figures, corrected fig.4 and references, published in J. Phys. Soc. Jpn. 79, 114711 (2010

    Построение оптимальных маршрутов на цифровых растровых картах

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    У статті запропоновано підхід до розв’язку навігаційної задачі трасування маршрутів руху мобільних об’єктів на прямокутній картографічній області. Показано, що для вирішення завдання оптимізації прокладання траси по цифрових картах найбільш придатним є алгоритм Беллмана. Запропоновано привести растрове зображення карти до вигляду прямокутної решітки, придатної до обробки методом Беллмана шляхом блокового квантування. Наведено результати роботи розробленого програмного забезпечення.In-process offered approach to the decision of navigation task of tracing of routes of motion of mobile objects on a rectangular cartographic area. It is shown that for the decision of task to optimization of gasket of route on digital maps most suitable is the use of algorithm of Bellman. It is suggested to bring a raster map over to the type of rectangular grate, suitable to treatment the method of Bellman by a sectional quantum. Job of the worked out software performances over are brought.В работе предложен подход к решению навигационной задачи трассировки маршрутов движения мобильных объектов на прямоугольной картографической области. Показано, что для решения задания оптимизации прокладки трассы по цифровым картам наиболее пригодным является использование алгоритма Беллмана. Предложено привести растровую карту к виду прямоугольной решетки, пригодной к обработке методом Беллмана путем блочного квантования. Приведены результаты работы разработанного программного обеспечения

    Observation of charge asymmetry dependence of pion elliptic flow and the possible chiral magnetic wave in heavy-ion collisions

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    We present measurements of π\pi^- and π+\pi^+ elliptic flow, v2v_2, at midrapidity in Au+Au collisions at sNN=\sqrt{s_{_{\rm NN}}} = 200, 62.4, 39, 27, 19.6, 11.5 and 7.7 GeV, as a function of event-by-event charge asymmetry, AchA_{ch}, based on data from the STAR experiment at RHIC. We find that π\pi^- (π+\pi^+) elliptic flow linearly increases (decreases) with charge asymmetry for most centrality bins at sNN=27 GeV\sqrt{s_{_{\rm NN}}} = \text{27 GeV} and higher. At sNN=200 GeV\sqrt{s_{_{\rm NN}}} = \text{200 GeV}, the slope of the difference of v2v_2 between π\pi^- and π+\pi^+ as a function of AchA_{ch} exhibits a centrality dependence, which is qualitatively similar to calculations that incorporate a chiral magnetic wave effect. Similar centrality dependence is also observed at lower energies.Comment: 6 pages, 4 figure

    Azimuthal anisotropy in U+U and Au+Au collisions at RHIC

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    Collisions between prolate uranium nuclei are used to study how particle production and azimuthal anisotropies depend on initial geometry in heavy-ion collisions. We report the two- and four-particle cumulants, v2{2}v_2\{2\} and v2{4}v_2\{4\}, for charged hadrons from U+U collisions at sNN\sqrt{s_{\rm NN}} = 193 GeV and Au+Au collisions at sNN\sqrt{s_{\rm NN}} = 200 GeV. Nearly fully overlapping collisions are selected based on the amount of energy deposited by spectators in the STAR Zero Degree Calorimeters (ZDCs). Within this sample, the observed dependence of v2{2}v_2\{2\} on multiplicity demonstrates that ZDC information combined with multiplicity can preferentially select different overlap configurations in U+U collisions. An initial-state model with gluon saturation describes the slope of v2{2}v_2\{2\} as a function of multiplicity in central collisions better than one based on Glauber with a two-component multiplicity model.Comment: Final paper version accepted for publication in Phys. Rev. Lett. New version includes comparisons to a constituent quark glauber mode

    Centrality and transverse momentum dependence of elliptic flow of multi-strange hadrons and ϕ\phi meson in Au+Au collisions at sNN\sqrt{s_{NN}} = 200 GeV

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    We present high precision measurements of elliptic flow near midrapidity (y<1.0|y|<1.0) for multi-strange hadrons and ϕ\phi meson as a function of centrality and transverse momentum in Au+Au collisions at center of mass energy sNN=\sqrt{s_{NN}}= 200 GeV. We observe that the transverse momentum dependence of ϕ\phi and Ω\Omega v2v_{2} is similar to that of π\pi and pp, respectively, which may indicate that the heavier strange quark flows as strongly as the lighter up and down quarks. This observation constitutes a clear piece of evidence for the development of partonic collectivity in heavy-ion collisions at the top RHIC energy. Number of constituent quark scaling is found to hold within statistical uncertainty for both 0-30%\% and 30-80%\% collision centrality. There is an indication of the breakdown of previously observed mass ordering between ϕ\phi and proton v2v_{2} at low transverse momentum in the 0-30%\% centrality range, possibly indicating late hadronic interactions affecting the proton v2v_{2}.Comment: 7 pages and 4 figures, Accepted for publication in Physical Review Letter

    Observation of Transverse Spin-Dependent Azimuthal Correlations of Charged Pion Pairs in p+pp^\uparrow+p at s=200\sqrt{s}=200 GeV

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    We report the observation of transverse polarization-dependent azimuthal correlations in charged pion pair production with the STAR experiment in p+pp^\uparrow+p collisions at RHIC. These correlations directly probe quark transversity distributions. We measure signals in excess of five standard deviations at high transverse momenta, at high pseudorapidities eta>0.5, and for pair masses around the mass of the rho-meson. This is the first direct transversity measurement in p+p collisions. Comparing the results to data from lepton-nucleon scattering will test the universality of these spin-dependent quantities.Comment: 11 pages, 5 figures, 15 tables. Submitted to PR

    Energy dependence of acceptance-corrected dielectron excess mass spectrum at mid-rapidity in Au+Au collisions at sNN=19.6\sqrt{s_{NN}} = 19.6 and 200 GeV

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    The acceptance-corrected dielectron excess mass spectra, where the known hadronic sources have been subtracted from the inclusive dielectron mass spectra, are reported for the first time at mid-rapidity yee<1|y_{ee}|<1 in minimum-bias Au+Au collisions at sNN\sqrt{s_{NN}} = 19.6 and 200 GeV. The excess mass spectra are consistently described by a model calculation with a broadened ρ\rho spectral function for Mee<1.1M_{ee}<1.1 GeV/c2c^{2}. The integrated dielectron excess yield at sNN\sqrt{s_{NN}} = 19.6 GeV for 0.4<Mee<0.750.4<M_{ee}<0.75 GeV/c2c^2, normalized to the charged particle multiplicity at mid-rapidity, has a value similar to that in In+In collisions at sNN\sqrt{s_{NN}} = 17.3 GeV. For sNN\sqrt{s_{NN}} = 200 GeV, the normalized excess yield in central collisions is higher than that at sNN\sqrt{s_{NN}} = 17.3 GeV and increases from peripheral to central collisions. These measurements indicate that the lifetime of the hot, dense medium created in central Au+Au collisions at sNN\sqrt{s_{NN}} = 200 GeV is longer than those in peripheral collisions and at lower energies.Comment: 9 pages, 6 figure

    Isolation of Flow and Nonflow Correlations by Two- and Four-Particle Cumulant Measurements of Azimuthal Harmonics in sNN=\sqrt{s_{_{\rm NN}}} = 200 GeV Au+Au Collisions

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    A data-driven method was applied to measurements of Au+Au collisions at sNN=\sqrt{s_{_{\rm NN}}} = 200 GeV made with the STAR detector at RHIC to isolate pseudorapidity distance Δη\Delta\eta-dependent and Δη\Delta\eta-independent correlations by using two- and four-particle azimuthal cumulant measurements. We identified a component of the correlation that is Δη\Delta\eta-independent, which is likely dominated by anisotropic flow and flow fluctuations. It was also found to be independent of η\eta within the measured range of pseudorapidity η<1|\eta|<1. The relative flow fluctuation was found to be 34%±2%(stat.)±3%(sys.)34\% \pm 2\% (stat.) \pm 3\% (sys.) for particles of transverse momentum pTp_{T} less than 22 GeV/cc. The Δη\Delta\eta-dependent part may be attributed to nonflow correlations, and is found to be 5%±2%(sys.)5\% \pm 2\% (sys.) relative to the flow of the measured second harmonic cumulant at Δη>0.7|\Delta\eta| > 0.7
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