82 research outputs found

    Probing the field-induced variation of the chemical potential in Bi(2)Sr(2)CaCu(2)O(y) via the magneto-thermopower measurements

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    Approximating the shape of the measured in Bi2Sr2CaCu2OyBi_2Sr_2CaCu_2O_y magneto-thermopower (TEP) ΔS(T,H)\Delta S(T,H) by asymmetric linear triangle of the form ΔS(T,H)Sp(H)±B±(H)(TcT)\Delta S(T,H)\simeq S_p(H)\pm B^{\pm}(H)(T_c-T) with positive B(H)B ^{-}(H) and B+(H)B ^{+}(H) defined below and above TcT_c, we observe that B+(H)2B(H)B ^{+}(H)\simeq 2B ^{-}(H). In order to account for this asymmetry, we explicitly introduce the field-dependent chemical potential of holes μ(H)\mu (H) into the Ginzburg-Landau theory and calculate both an average ΔSav(T,H)\Delta S_{av}(T,H) and fluctuation ΔSfl(T,H)\Delta S_{fl}(T,H) contributions to the total magneto-TEP ΔS(T,H)\Delta S(T,H). As a result, we find a rather simple relationship between the field-induced variation of the chemical potential in this material and the above-mentioned magneto-TEP data around TcT_c, viz. Δμ(H)Sp(H)\Delta \mu (H)\propto S_p(H).Comment: REVTEX (epsf), 4 pages, 2 PS figures; to be published in JET

    О построении интеллектуальной подсистемы анализа параметров сортировочного узла

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    For the English abstract and full text of the article please see the attached PDF-File (English version follows Russian version).The work was supported by the Russian Fundamental Research Foundation, project 17-20-01133 ofi_m_ Russian Railways. ABSTRACT The article considers the issues of continuous monitoring of the situation at the marshalling yard and detection of the possibility of occurrence of dangerous situations. An approach is proposed for constructing an automated intellectual subsystem for analyzing and timely forecasting the critical utilization of railway sorting units. The solution of the problem is proposed with the help of network communication technologies due to the use of information from automated data collection systems and the neural network decision support subsystem. Keywords: transport, intellectual system, system analysis, forecasting of critical situations, simulation modeling, sorting node, neural network, information, communication technologies.Текст аннотации на англ. языке и полный текст статьи на англ. языке находится в прилагаемом файле ПДФ (англ. версия следует после русской версии). Работа выполнена при поддержке РФФИ, проект 17-20-01133 офи_м_РЖД. В работе рассмотрены вопросы непрерывного мониторинга обстановки на сортировочной станции и выявления возможности возникновения опасных ситуаций. Предлагается подход к построению автоматизированной интеллектуальной подсистемы анализа и своевременного прогнозирования критической загруженности железнодорожных сортировочных узлов. Предложено решение задачи с помощью сетевых коммуникационных технологий за счёт использования информации от автоматизированных систем сбора данных и нейросетевой подсистемы поддержки принятия решений

    Achilles tendon rupture prevention in physical activity and sports: predisposition factors

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    Objective: to summarize all clinically significant factors determining the Achilles tendon predisposition to rupture.Materials and methods: the basis of this scientific-analytical review was the analysis of data from the electronic portals PubMed-NCBI, Google Academy, and “Scientific electronic e-Library.ru”.Results: the presented literature review indicates that injuries and ruptures of the Achilles tendon can be provoked by numerous factors, among which genetic predisposition, individual anatomico-morphological features of the tendon complex structure, initial connective tissue failure, pathological changes in the Achilles tendon structure itself, foot and ankle deformities are of great importance. Men are more susceptible to this injury. Tendon injuries are most common either in 30–40 years, or in the period from 60 to 80 years. Professional athletes and people who lead sedentary lifestyles and do not exercise properly are at risk of Achilles tendon ruptures. Concomitant metabolic disorders and use of some medications also play an important role in the predisposition to this injury. Local corticosteroid injections pose a particular tendon rupture risk. The combination of several established factors significantly increases the likelihood of this emergency.Conclusions: early detection of predisposition to Achilles tendon rupture will allow timely development of effective measures for its prevention in physical training and sports

    High-frequency homogenization for periodic media

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    This article is available open access through the publisher’s website at the link below. Copyright @ 2010 The Royal Society.An asymptotic procedure based upon a two-scale approach is developed for wave propagation in a doubly periodic inhomogeneous medium with a characteristic length scale of microstructure far less than that of the macrostructure. In periodic media, there are frequencies for which standing waves, periodic with the period or double period of the cell, on the microscale emerge. These frequencies do not belong to the low-frequency range of validity covered by the classical homogenization theory, which motivates our use of the term ‘high-frequency homogenization’ when perturbing about these standing waves. The resulting long-wave equations are deduced only explicitly dependent upon the macroscale, with the microscale represented by integral quantities. These equations accurately reproduce the behaviour of the Bloch mode spectrum near the edges of the Brillouin zone, hence yielding an explicit way for homogenizing periodic media in the vicinity of ‘cell resonances’. The similarity of such model equations to high-frequency long wavelength asymptotics, for homogeneous acoustic and elastic waveguides, valid in the vicinities of thickness resonances is emphasized. Several illustrative examples are considered and show the efficacy of the developed techniques.NSERC (Canada) and the EPSRC

    Цифровая модель: прогноз поведения в транспортных процессах

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    In today’s world, many processes and events depend on forecasting. With development of mathematical models, an increasing number of factors influencing the final result of the forecast are taken into account, which in turn leads to the use of neural networks. But for training a neural network, source data sets are required, which are often not always sufficient or may not exist at all. The article describes a method of obtaining information as close to reality as possible. The proposed approach is to generate input data using simulation models of an object. The solution of a problem of generation of data sets and of training of a neural network is shown at the example of a typical marshalling railway station, and of a simulation of operations of a shunting hump. The considered examples confirmed the validity of the proposed methodological approach to generation of source data for neural networks using simulation models of a real object, based on a digital mathematical model, which makes it possible to obtain a simulation model of movement of transport objects, which is reliable in forecasting transport processes and creating relevant control algorithms.В современном мире многие процессы и события зависят от прогнозирования. С развитием математических моделей учитывается всё большее количество факторов, влияющих на конечный результат прогноза, что, в свою очередь, делает всё более актуальным использование нейронных сетей. Но для обучения нейронной сети требуются исходные наборы данных, которые зачастую не всегда достаточны или вовсе могут отсутствовать. В статье рассмотрен способ получения максимально приближенной к реалиям информации. Предлагаемый подход заключается в генерации исходных данных с помощью имитационных моделей объекта. Показано решение задачи генерации наборов данных и обучения на их основе нейронной сети на примере типового сортировочного железнодорожного узла, имитации работы сортировочной горки

    Нейронная сеть для прогнозирования нагрузок энергопотребления сортировочного узла

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    A multilayer neural network has been designed to forecast average daily energy consumption of a railway marshalling yard. The suggested model comprises a multilayer perceptron using 22 inputs, the n-th number of hidden layers and one output. The number of hidden layers in the neural network and neurons in them was chosen experimentally. A comparative selection of activation functions and training methods has allowed for all other parameters to achieve a minimum average relative error. Two types of loads corresponding to holidays (non-working) and working days were identified. An additional input node with binary coding and two nodes for coding the season were introduced due to a certain repeatability characterizing samples of prediction of loads of energy consumption of the marshalling yard depending on type of a day and on a season. As accounting of the dependence of the forecast on load values in previous days and years (dynamic dependencies) is most important factor, this neural network takes into account the average daily energy consumption during four days of the current period, precedingthe forecasted date, and the average daily power consumption during four days prior to this date during last three years.As a result, considering all factors and experimentally selected parameters of the neural network, the minimum resulting error of MAPE is about 1,4 %, which shows the advantage of the developed neural network in comparison with two other methods of solution of the problem, suggested by other researchers.Предложено описание многослойной нейронной сети, предназначенной для предсказания среднесуточного потребления электроэнергии сортировочным узлом железной дороги. Для решения данной задачи была построена модель на основе многослойного персептрона, использующая 22 входа, n-ое количество скрытых слоёв и один выход. Количество скрытых слоёв в нейросети и нейронов в них было подобрано экспериментально.Проведён сравнительный подбор функций активации и методов обучения, позволяющих при всех прочих параметрах достичь минимальной средней относительной ошибки.Выделено два вида нагрузок, соответствующих праздничным (нерабочим) и рабочим дням, что потребовало введения одного дополнительного входного узла с двоичным кодированием и двух узлов для кодирования времени года, что обусловлено определённой повторяемостью характеризующих выборок предсказания нагрузок потребления энергии узла сортировочной станции в зависимости от типа дня и времени года. Важнейшим фактором также являлся учёт зависимости прогноза от значений нагрузки в предыдущие дни и годы (динамические зависимости), и в данной нейросети учтено среднесуточное потребление энергии по данным четырёх предыдущих дней текущего периода и четырёх предыдущих дней за последние три года.В итоге, с учётом всех факторов и экспериментально подобранных параметров нейросети, минимальная получившаяся погрешность MAPE составляет порядка 1,4 %, что, в сравнении с двумя сторонними решениями для данной задачи, показывает преимущество разработанной нейросети

    Transverse-momentum-dependent Multiplicities of Charged Hadrons in Muon-Deuteron Deep Inelastic Scattering

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    A semi-inclusive measurement of charged hadron multiplicities in deep inelastic muon scattering off an isoscalar target was performed using data collected by the COMPASS Collaboration at CERN. The following kinematic domain is covered by the data: photon virtuality Q2>1Q^{2}>1 (GeV/cc)2^2, invariant mass of the hadronic system W>5W > 5 GeV/c2c^2, Bjorken scaling variable in the range 0.003<x<0.40.003 < x < 0.4, fraction of the virtual photon energy carried by the hadron in the range 0.2<z<0.80.2 < z < 0.8, square of the hadron transverse momentum with respect to the virtual photon direction in the range 0.02 (GeV/c)2<PhT2<3c)^2 < P_{\rm{hT}}^{2} < 3 (GeV/cc)2^2. The multiplicities are presented as a function of PhT2P_{\rm{hT}}^{2} in three-dimensional bins of xx, Q2Q^2, zz and compared to previous semi-inclusive measurements. We explore the small-PhT2P_{\rm{hT}}^{2} region, i.e. PhT2<1P_{\rm{hT}}^{2} < 1 (GeV/cc)2^2, where hadron transverse momenta are expected to arise from non-perturbative effects, and also the domain of larger PhT2P_{\rm{hT}}^{2}, where contributions from higher-order perturbative QCD are expected to dominate. The multiplicities are fitted using a single-exponential function at small PhT2P_{\rm{hT}}^{2} to study the dependence of the average transverse momentum PhT2\langle P_{\rm{hT}}^{2}\rangle on xx, Q2Q^2 and zz. The power-law behaviour of the multiplicities at large PhT2P_{\rm{hT}}^{2} is investigated using various functional forms. The fits describe the data reasonably well over the full measured range.Comment: 28 pages, 20 figure

    Возможности текстурного анализа лучевых методов визуализации в диагностике образований паренхимы почки

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    This review outlines current trends in applying texture analysis for the treatment of patients with renal parenchyma tumor. The prospects of using radiomics in the diagnosis and treatment of patients with renal cell carcinoma are presented.В настоящем обзоре изложены основные направления текстурного анализа в лечении пациентов с образованиями паренхимы почки, используемые в современной медицине. Представлены возможности применения радиомики в диагностике и лечении больных с почечно-клеточным раком

    Corrigendum to "Transverse extension of partons in the proton probed in the sea-quark range by measuring the DVCS cross section" [Phys. Lett. B 793 (2019) 188]

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    Light isovector resonances in π-p →π-π-π+p at 190 GeV/c

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    We have performed the most comprehensive resonance-model fit of π-π-π+ states using the results of our previously published partial-wave analysis (PWA) of a large data set of diffractive-dissociation events from the reaction π-+p→π-π-π++precoil with a 190 GeV/c pion beam. The PWA results, which were obtained in 100 bins of three-pion mass, 0.5<2.5 GeV/c2, and simultaneously in 11 bins of the reduced four-momentum transfer squared, 0.1<1.0 (GeV/c)2, are subjected to a resonance-model fit using Breit-Wigner amplitudes to simultaneously describe a subset of 14 selected waves using 11 isovector light-meson states with JPC=0-+, 1++, 2++, 2-+, 4++, and spin-exotic 1-+ quantum numbers. The model contains the well-known resonances π(1800), a1(1260), a2(1320), π2(1670), π2(1880), and a4(2040). In addition, it includes the disputed π1(1600), the excited states a1(1640), a2(1700), and π2(2005), as well as the resonancelike a1(1420). We measure the resonance parameters mass and width of these objects by combining the information from the PWA results obtained in the 11 t′ bins. We extract the relative branching fractions of the ρ(770)π and f2(1270)π decays of a2(1320) and a4(2040), where the former one is measured for the first time. In a novel approach, we extract the t′ dependence of the intensity of the resonances and of their phases. The t′ dependence of the intensities of most resonances differs distinctly from the t′ dependence of the nonresonant components. For the first time, we determine the t′ dependence of the phases of the production amplitudes and confirm that the production mechanism of the Pomeron exchange is common to all resonances. We have performed extensive systematic studies on the model dependence and correlations of the measured physical parameters
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