3,036 research outputs found

    Electrodermal Activity: Simultaneous Recordings

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    Electrodermal activity (EDA) is a sensitive measure of the sympathetic nervous system activity. It is used to describe changes in the skin electrical properties. This chapter aimed to show advantages of simultaneous recordings of EDA parameters at the same skin site over other recordings. The literature databases, Web of Science and Google Scholar, were searched using terms like “electrodermal activity,” “sequential recording,” “simultaneous recording,” “skin conductance,” “skin potential,” and “skin susceptance.” Articles that include sequential and/or simultaneous recording of EDA parameters were analyzed. The chapter presents a description of the oldest and current methods used for recording EDA parameters and an explanation of the newest techniques used in EDA researches. Although sequential recordings are predominant and widely spreading, much effort has been made to simultaneously record skin conductance (SC) and skin potential (SP), and recently researchers realized the capability of simultaneously recording SC, SP, and skin susceptance (SS) at the same skin site. The advantage of simultaneous over the sequence measurements is that the latter must be manually time realigned when measured by different instruments, which means it is time-consuming. Although the simultaneous measurements are used exclusively for research purposes at this stage, this may open horizons in the modern trends of psychophysiology applications in the near future

    Human Emotion Recognition from Motion Using a Radial Basis Function Network Architecture

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    (Also cross-referenced as CAR-TR-721) In this paper a radial basis function network architecture is developed that learns the correlation between facial feature motion patterns and human emotions. We describe a hierarchical approach which at the highest level identifies emotions, at the mid level determines motions of facial features, and at the low level recovers motion directions. Individual emotion networks were trained to recognize the 'smile" and "surprise" emotions. Each network was trained by viewing a set of sequences of one emotion for many subjects. The trained neural network was then tested for retention, extrapolation and rejection ability. Success rates were about 88% for retention, 73Wo for extrapolation, and 79% for rejection

    Optimum Tilt Angle for South Facing Flat Solar Collectors in Duhok City

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    One of the important parameters that affect the performance of a solar collector is its, tilt angle with the horizon. This is because of the variation of tilt angle changes the amount of solar radiation reaching the collector surface. In this paper, the global irradiation observed in Duhok from 1990 to 2007 was used to estimate the optimal tilt angle for solar collectors. The observed data are resolved into diffusion, beam and albedo components. Total solar radiation on the solar collector surface with an optimum tilt angle is computed for specific periods. It is found that the optimum tilt angle changes between 0◩ (June) and 62◩ (December) throughout the year. In winter (December, January, and February) the tilt should be 58◩, in spring (March, April, and May) 20, in summer (June, July, and August) 5◩, and in autumn (September, October, and November) 46.3◩. The yearly average of this value was found to be 32.33◩ and this would be the optimum fixed tilt throughout the year

    Theoretical and Experimental Considerations for Neutrinoless Double Beta Decay

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    In the rst part of this work we show some theoretical aspects of the generation of the neutrino mass by means of a direct extension of the Standard Model of particles, which include the presence of heavy right-handed neutrinos and large Majorana mass terms. From these two new ingredients, it is possible to nd a mass for the light neutrinos which is naturally of the order of 1 eV or less. The idea is to put these theoretical aspects in the context of the search for neutrino mass values by the study of the signal from the Neutrinoless Double Beta Decay Process (0 ). In the second part, a brief summary is given of the experimental considerations required for the measurement of effective Majorana neutrino mass using (0 ). Measurement strategies and background considerations are introduced and an outline of both active and passive methods is given. Finally, current results are discussed with particular emphasis on the HeidelbergMoscow experiment. This note is based on the presentation given at the CERNCLAF 4th Latin American School on High-Energy Physics

    Recognising facial expressions in video sequences

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    We introduce a system that processes a sequence of images of a front-facing human face and recognises a set of facial expressions. We use an efficient appearance-based face tracker to locate the face in the image sequence and estimate the deformation of its non-rigid components. The tracker works in real-time. It is robust to strong illumination changes and factors out changes in appearance caused by illumination from changes due to face deformation. We adopt a model-based approach for facial expression recognition. In our model, an image of a face is represented by a point in a deformation space. The variability of the classes of images associated to facial expressions are represented by a set of samples which model a low-dimensional manifold in the space of deformations. We introduce a probabilistic procedure based on a nearest-neighbour approach to combine the information provided by the incoming image sequence with the prior information stored in the expression manifold in order to compute a posterior probability associated to a facial expression. In the experiments conducted we show that this system is able to work in an unconstrained environment with strong changes in illumination and face location. It achieves an 89\% recognition rate in a set of 333 sequences from the Cohn-Kanade data base

    Precise measurement of the top quark mass in the dilepton channel at D0

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    We measure the top quark mass (mt) in ppbar collisions at a center of mass energy of 1.96 TeV using dilepton ttbar->W+bW-bbar->l+nubl-nubarbbar events, where l denotes an electron, a muon, or a tau that decays leptonically. The data correspond to an integrated luminosity of 5.4 fb-1 collected with the D0 detector at the Fermilab Tevatron Collider. We obtain mt = 174.0 +- 1.8(stat) +- 2.4(syst) GeV, which is in agreement with the current world average mt = 173.3 +- 1.1 GeV. This is currently the most precise measurement of mt in the dilepton channel.Comment: 7 pages, 4 figure

    Search for right-handed W bosons in top quark decay

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    We present a measurement of the fraction f+ of right-handed W bosons produced in top quark decays, based on a candidate sample of ttˉt\bar{t} events in the lepton+jets decay mode. These data correspond to an integrated luminosity of 230pb^-1, collected by the DO detector at the Fermilab Tevatron ppˉp\bar{p} Collider at sqrt(s)=1.96 TeV. We use a constrained fit to reconstruct the kinematics of the ttˉt\bar{t} and decay products, which allows for the measurement of the leptonic decay angle ξ∗\theta^* for each event. By comparing the cos⁡ξ∗\cos\theta^* distribution from the data with those for the expected background and signal for various values of f+, we find f+=0.00+-0.13(stat)+-0.07(syst). This measurement is consistent with the standard model prediction of f+=3.6x10^-4.Comment: Submitted to Physical Review D Rapid Communications 7 pages, 3 figure

    Measurement of the Lifetime Difference in the B_s^0 System

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    We present a study of the decay B_s^0 -> J/psi phi We obtain the CP-odd fraction in the final state at time zero, R_perp = 0.16 +/- 0.10 (stat) +/- 0.02 (syst), the average lifetime of the (B_s, B_sbar) system, tau (B_s^0) =1.39^{+0.13}_{-0.16} (stat) ^{+0.01}_{-0.02} (syst) ps, and the relative width difference between the heavy and light mass eigenstates, Delta Gamma/Gamma = (Gamma_L - Gamma_H)/Gamma =0.24^{+0.28}_{-0.38} (stat) ^{+0.03}_{-0.04} (syst). With the additional constraint from the world average of the B_s^0$lifetime measurements using semileptonic decays, we find tau (B_s^0)= 1.39 +/- 0.06 ~ps and Delta Gamma/\Gamma = 0.25^{+0.14}_{-0.15}. For the ratio of the B_s^0 and B^0 lifetimes we obtain tau(B_s^0)/tau(B^0)} = 0.91 +/- 0.09 (stat) +/- 0.003 (syst).Comment: submitted to Phys. Rev. Lett. FERMILAB-PUB-05-324-

    Measurement of Semileptonic Branching Fractions of B Mesons to Narrow D** States

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    Using the data accumulated in 2002-2004 with the DO detector in proton-antiproton collisions at the Fermilab Tevatron collider with centre-of-mass energy 1.96 TeV, the branching fractions of the decays B -> \bar{D}_1^0(2420) \mu^+ \nu_\mu X and B -> \bar{D}_2^{*0}(2460) \mu^+ \nu_\mu X and their ratio have been measured: BR(\bar{b}->B) \cdot BR(B-> \bar{D}_1^0 \mu^+ \nu_\mu X) \cdot BR(\bar{D}_1^0 -> D*- pi+) = (0.087+-0.007(stat)+-0.014(syst))%; BR(\bar{b}->B)\cdot BR(B->D_2^{*0} \mu^+ \nu_\mu X) \cdot BR(\bar{D}_2^{*0} -> D*- \pi^+) = (0.035+-0.007(stat)+-0.008(syst))%; and (BR(B -> \bar{D}_2^{*0} \mu^+ \nu_\mu X)BR(D2*0->D*- pi+)) / (BR(B -> \bar{D}_1^{0} \mu^+ \nu_\mu X)\cdot BR(\bar{D}_1^{0}->D*- \pi^+)) = 0.39+-0.09(stat)+-0.12(syst), where the charge conjugated states are always implied.Comment: submitted to Phys. Rev. Let

    Measurement of the B0_s semileptonic branching ratio to an orbitally excited D_s** state, Br(B0_s -> Ds1(2536) mu nu)

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    In a data sample of approximately 1.3 fb-1 collected with the D0 detector between 2002 and 2006, the orbitally excited charm state D_s1(2536) has been observed with a measured mass of 2535.7 +/- 0.6 (stat) +/- 0.5 (syst) MeV via the decay mode B0_s -> D_s1(2536) mu nu X. A first measurement is made of the branching ratio product Br(b(bar) -> D_s1(2536) mu nu X).Br(D_s1(2536)->D* K0_S). Assuming that D_s1(2536) production in semileptonic decay is entirely from B0_s, an extraction of the semileptonic branching ratio Br(B0_s -> D_s1(2536) mu nu X) is made.Comment: 7 pages, 2 figures, LaTeX, version with minor changes as accepted by Phys. Rev. Let
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