811 research outputs found

    Горячая точка Северного Вьетнама

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    There are evidences of existence in North Western mountainous district of Vietnam of the long term developed hot spot with function of which are connected: intraplate magmatizm of the two epochs P2 - T1 and J2 - K1; forming under these volcanic fields mantle cannel until depth of 600 km; forming into this cannel on the depth interval of 150-300 km zoning heated mantle; connected with heated mantle high seismisity of the district.Имеются свидетельства существования в горном Северо-Западном районе Вьетнама горячей точки длительного развития, с функционированием которой связаны: внутриплитный магматизм Р2 - Т1, J3 - K1; формирование под вулканическими полями мантийного канала глубиной до 600 км; образование в этом канале на глубинах 150-300 км области разгоряченной мантии; обусловленная последним высокая сейсмичность района

    Online change detection for energy-efficient mobilec crowdsensing

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    Mobile crowdsensing is power hungry since it requires continuously and simultaneously sensing, processing and uploading fused data from various sensor types including motion sensors and environment sensors. Realizing that being able to pinpoint change points of contexts enables energy-efficient mobile crowdsensing, we modify histogram-based techniques to efficiently detect changes, which has less computational complexity and performs better than the conventional techniques. To evaluate our proposed technique, we conducted experiments on real audio databases comprising 200 sound tracks. We also compare our change detection with multivariate normal distribution and one-class support vector machine. The results show that our proposed technique is more practical for mobile crowdsensing. For example, we show that it is possible to save 80% resource compared to standard continuous sensing while remaining detection sensitivity above 95%. This work enables energy-efficient mobile crowdsensing applications by adapting to contexts

    Application of a wireless sensor system for object protection using infrared sensors

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    В работе был рассмотрен алгоритм, выносящий решение о наличии или отсутствии проникновения на охраняемый объект на основе данных, получаемых датчиками инфракрасного излучения, входящими в беспроводную сенсорную систему. На основе теоретических положений приведены методики расчета ослабления средой инфракрасного излучения, в том числе ослабления за счет молекулярных газов и аэрозольного ослабления. Показаны особенности влияния окружающей среды на функционирование локальных тепловых сенсоров. Также рассмотрены особенности характеристик помехоустойчивости канала радиосвязи с учетом замираний. С целью анализа влияния среды на эффективность всей системы приведены зависимости полной вероятности ошибки от энергетического параметра как с учетом ослабления инфракрасного излучения средой на уровне локальных сенсоров, так и с учетом замираний в канале радиосвязи. Кроме того, приведена зависимость полной вероятности ошибки от дистанции связи под влиянием замираний. Выполнен анализ полученных результатов и оценена степень влияния среды распространения на качество функционирования беспроводной сенсорной системы теплового вида. При этом показано, что сложные метеоусловия могут оказать существенное влияние на эффективность функционирования локальных сенсоров, а следовательно, и всей системы. Однако, несмотря на возможное существенное ухудшение эффективности вследствие ослабления инфракрасного излучения, а также замираний в канале радиосвязи, эффективность может быть повышена за счет увеличения количества используемых сенсоров. In this work, an algorithm that makes decisions on whether or not an object under protection has been penetrated based on data from infrared (IR) sensors included in a wireless sensor system is considered. Based on theoretical considerations, methods for calculating the attenuation of infrared radiation by the medium, including attenuation due to molecular gases and aerosol attenuation, are presented. Peculiarities of the external environment impact on the functioning of local heat sensors are shown. Also, peculiarities of the noise immunity characteristics of a radio communication channel are considered with due regard for signal fading. With the purpose of analyzing the environment impact on the efficiency of the entire system, we present dependencies of the total error probability on the energy parameter, taking into account the attenuation of infrared radiation in both the environment at the level of local sensors and the radio communication channel. In addition, a dependence of the total error probability on the communication distance under the influence of fading is presented. The results arrived at are analyzed and the degree of influence of the environment on the quality of functioning of the wireless sensor system of thermal type is evaluated. It is shown that adverse weather conditions can have a significant impact on the efficiency of local sensors, and, hence the entire system. However, despite the possible significant deterioration in efficiency due to the IR signal attenuation in the medium and in the radio channel, the efficiency can be increased by increasing the number of sensors used

    Quantum Statistical Model of Nuclear Multifragmentation in the Canonical Ensemble Method

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    A quantum statistical model of nuclear multifragmentation is proposed. The recurrence equation method used within the canonical ensemble makes the model solvable and transparent to physical assumptions and allows to get results without involving the Monte Carlo technique. The model exhibits the first order phase transition. Quantum statistics effects are clearly seen on the microscopic level of occupation numbers but are almost washed out for global thermodynamic variables and the averaged observables studied. In the latter case, the recurrence relations for multiplicity distributions of both intermediate-mass and all fragments are derived and the specific changes in the shape of multiplicity distributions in the narrow region of the transition temperature is stressed. The temperature domain favorable to search for the HBT effect is noted.Comment: 38 pages, 11 figure

    Anomalous radial expansion in central heavy-ion reactions

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    The expansion velocity profile in central heavy-ion reactions in the Fermi energy domain is examined. The radial expansion is non-hubblean and in the surface region it scales proportional to a higher exponent (α>1\alpha > 1) of the radius. The anomalous expansion velocity profile is accompanied by a power law nucleon density profile in the surface region. Both these features of central heavy-ion reactions disappear at higher energies, and the system follows a uniform Hubble expansion (α1\alpha \simeq 1)

    νdμΔ++n\nu d \to \mu^- \Delta^{++} n Reaction and Axial Vector NΔN-\Delta Coupling

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    The reaction νdμΔ++n\nu d \to \mu^- \Delta^{++} n is studied in the region of low q2q^2 to investigate the effect of deuteron structure and width of the Δ\Delta resonance on the differential cross section. The results are used to extract the axial vector NΔN-\Delta coupling C5AC^{A}_5 from the experimental data on this reaction. The possibility to determine this coupling from electroweak interaction experiments with high intensity electron accelerators is discussed.Comment: 14 pages, REVTEX, 5 figure

    Statistical Multifragmentation of Non-Spherical Expanding Sources in Central Heavy-Ion Collisions

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    We study the anisotropy effects measured with INDRA at GSI in central collisions of Xe+Sn at 50 A.MeV and Au+Au at 60, 80, 100 A.MeV incident energy. The microcanonical multifragmentation model with non-spherical sources is used to simulate an incomplete shape relaxation of the multifragmenting system. This model is employed to interpret observed anisotropic distributions in the fragment size and mean kinetic energy. The data can be well reproduced if an expanding prolate source aligned along the beam direction is assumed. An either non-Hubblean or non-isotropic radial expansion is required to describe the fragment kinetic energies and their anisotropy. The qualitative similarity of the results for the studied reactions suggests that the concept of a longitudinally elongated freeze-out configuration is generally applicable for central collisions of heavy systems. The deformation decreases slightly with increasing beam energy.Comment: 35 pages, 19 figures, submitted to Nuclear Physics

    Spin asymmetry A_1^d and the spin-dependent structure function g_1^d of the deuteron at low values of x and Q^2

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    We present a precise measurement of the deuteron longitudinal spin asymmetry A_1^d and of the deuteron spin-dependent structure function g_1^d at Q^2 < 1 GeV^2 and 4*10^-5 < x < 2.5*10^-2 based on the data collected by the COMPASS experiment at CERN during the years 2002 and 2003. The statistical precision is tenfold better than that of the previous measurement in this region. The measured A_1^d and g_1^d are found to be consistent with zero in the whole range of x.Comment: 17 pages, 10 figure

    Gluon polarization in the nucleon from quasi-real photoproduction of high-pT hadron pairs

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    We present a determination of the gluon polarization Delta G/G in the nucleon, based on the helicity asymmetry of quasi-real photoproduction events, Q^2<1(GeV/c)^2, with a pair of large transverse-momentum hadrons in the final state. The data were obtained by the COMPASS experiment at CERN using a 160 GeV polarized muon beam scattered on a polarized 6-LiD target. The helicity asymmetry for the selected events is = 0.002 +- 0.019(stat.) +- 0.003(syst.). From this value, we obtain in a leading-order QCD analysis Delta G/G=0.024 +- 0.089(stat.) +- 0.057(syst.) at x_g = 0.095 and mu^2 =~ 3 (GeV}/c)^2.Comment: 10 pages, 3 figure

    The Deuteron Spin-dependent Structure Function g1d and its First Moment

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    We present a measurement of the deuteron spin-dependent structure function g1d based on the data collected by the COMPASS experiment at CERN during the years 2002-2004. The data provide an accurate evaluation for Gamma_1^d, the first moment of g1d(x), and for the matrix element of the singlet axial current, a0. The results of QCD fits in the next to leading order (NLO) on all g1 deep inelastic scattering data are also presented. They provide two solutions with the gluon spin distribution function Delta G positive or negative, which describe the data equally well. In both cases, at Q^2 = 3 (GeV/c)^2 the first moment of Delta G is found to be of the order of 0.2 - 0.3 in absolute value.Comment: fits redone using MRST2004 instead of MRSV1998 for G(x), correlation matrix adde
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