Mise en œuvre d’une méthode de Data Mining pour appréhender le comportement d’un sujet en état de tunnélisation attentionnelle

Dans l’aéronautique, on considère que 80% des accidents sont dus à une erreur humaine dans l’aviation civil et militaire (O'Hare, Wiggins, Batt, & Morrison, 1994) (Wiegmann & Shappell, 2003). Ces statistiques ont donc amené nombre de scientifiques à s’intéresser au sujet des facteurs humains. L’idée est d’améliorer la sécurité aérienne en comprenant mieux le comportement humain. On s’aperçoit en effet que certains accidents rejoués en simulateur par d’autres pilotes expérimentés conduisent parfois au même crash (Wanner & Wanner, 1999). C’est parfois l’environnement qui conduit à l’erreur humaine. Ainsi il est intéressant de rechercher des moyens d’aider l’opérateur dans sa tâche. Ce n’est pas chose si aisée. Van Eslande et al (Van Eslande, Erreur de conduite et besoin d’aide : une approche accidentologique, 2001) (Van Eslande, Alberton, Nachtergaële, & Blancher, 1997) postulent que le comportement des automobilistes est essentiellement conditionné par les infrastructures routières. Il a été remarqué que les conflits étaient un précurseur remarquable d’erreurs humaines conduisant à l’accident. Des confits entre l’humain et la machine, ou entre l’opérateur et la tour de contrôle, ou encore entre le pilote et le co-pilote. L’étude des conflits s’avère alors un thème pertinent pour les facteurs humains. C’est dans ce domaine que nous travaillons au CAS au sein de l’ISAE. Le rapport sera constitué de trois grandes sections. Dans un premier temps nous présenterons l’environnement de travail à l’ISAE. Puis dans les parties suivantes nous définirons de manière plus précise ce qu’est la « tunnélisation attentionnelle » et décrirons plus en profondeur l’expérience du robot qui est notre base de travail. Enfin nous présenterons les résultats en termes de diagnostic de l’état d’un opérateur

Formal Detection of Attentional Tunneling in Human Operator-Automation Interactions

The allocation of visual attention is a key factor for the humans when operating complex systems under time pressure with multiple information sources. In some situations, attentional tunneling is likely to appear and leads to excessive focus and poor decision making. In this study, we propose a formal approach to detect the occurrence of such an attentional impairment that is based on machine learning techniques. An experiment was conducted to provoke attentional tunneling during which psycho-physiological and oculomotor data from 23 participants were collected. Data from 18 participants were used to train an adaptive neuro-fuzzy inference system (ANFIS). From a machine learning point of view, the classification performance of the trained ANFIS proved the validity of this approach. Furthermore, the resulting classification rules were consistent with the attentional tunneling literature. Finally, the classifier was robust to detect attentional tunneling when performing over test data from four participants

A search for W bb and W Higgs production in ppbar collisions at sqrt(s)=1.96 TeV

We present a search for W b \bar{b} production in p \bar{p} collisions at sqrt{s}=1.96 TeV in events containing one electron, an imbalance in transverse momentum, and two b-tagged jets. Using 174 pb-1 of integrated luminosity accumulated by the D0 experiment at the Fermilab Tevatron collider, and the standard-model description of such events, we set a 95% C.L. upper limit on W b \bar{b}$production of 6.6 pb for b quarks with transverse momenta p_T^b > 20 GeV and b \bar{b} separation in pseudorapidity-azimuth space Delta R_bb > 0.75. Restricting the search to optimized b \bar{b} mass intervals provides upper limits on$WH$production of 9.0$-$12.2 pb, for Higgs-boson masses of 105$-$135 GeV.Comment: 7 pages, 4 figures, 1 table, submitted to Physical Review Letter

Study of ZγZ\gamma events and limits on anomalous ZZγZZ\gamma and ZγγZ\gamma\gamma couplings in ppbar collisions at sqrt(s)=1.96sqrt(s) = 1.96 TeV

We present a measurement of the Z\gamma production cross section and limits on anomalous ZZ\gamma and Z\gamma\gamma couplings for form-factor scales of Lambda = 750 and 1000 GeV. The measurement is based on 138 (152) candidate events in the ee\gamma (\mu\mu\gamma) final state using 320 (290) pb^{-1} of ppbar collisions at \sqrt{s} = 1.96 TeV. The 95% C.L. limits on real and imaginary parts of individual anomalous couplings are |h_{10,30}^{Z}|<0.23, |h_{20,40}^{Z}|<0.020, |h_{10,30}^{\gamma}|<0.23, and |h_{20,40}^{\gamma}|<0.019 for Lambda = 1000 GeV.Comment: submitted to Phys. Rev. Letter

Measurement of the Ratio of B+ and B0 Meson Lifetimes

The ratio of B+ and B0 meson lifetimes was measured using data collected in 2002-2004 by the D0 experiment in Run II of the Fermilab Tevatron Collider. These mesons were reconstructed in B -> mu+ nu D*- X decays, which are dominated by B0, and B ->mu+ nu D0bar X decays, which are dominated by B+. The ratio of lifetimes is measured to be t+/t0 = 1.080 +- 0.016(stat) +- 0.014(syst).Comment: 7 pages, 2 figures, LaTeX, to be submitted to Physical Review Letter

A Search for the Flavor-Changing Neutral Current Decay B0_s -> mu^+mu^- in pp(bar) Collisions at \sqrt{s} = 1.96 TeV with the D0 Detector

We present the results of a search for the flavor-changing neutral current decay B0_s -> mu+ mu- using a data set with integrated luminosity of 240 pb^{-1} of pp(bar) collisions at sqrt{s}=1.96 TeV collected with the D0 detector in Run II of the Fermilab Tevatron collider. We find the upper limit on the branching fraction to be Br(B0_s -> mu+ mu-) \leq 5.0 x 10^{-7} at the 95% C.L. assuming no contributions from the decay B0_d -> mu+ mu- in the signal region. This limit is the most stringent upper bound on the branching fraction B0_s -> mu+ mu- to date.Comment: 7 pages, 3 figures, LaTeX, to be submitted to Physical Review Letters, minor changes to text, reference adde

Data assimilation in a system with two scales-combining two initialization techniques

11 pages, 11 figures, 1 tableFull-text version available Open Access at: http://clivar.iim.csic.es/?q=es/node/319An ensemble Kalman filter (EnKF) is used to assimilate data onto a non-linear chaotic model, coupling two kinds of variables. The first kind of variables of the system is characterized as large amplitude, slow, large scale, distributed in eight equally spaced locations around a circle. The second kind of variables are small amplitude, fast, and short scale, distributed in 256 equally spaced locations. Synthetic observations are obtained from the model and the observational error is proportional to their respective amplitudes. The performance of the EnKF is affected by differences in the spatial correlation scales of the variables being assimilated. This method allows the simultaneous assimilation of all the variables. The ensemble filter also allows assimilating only the large-scale variables, letting the small-scale variables to freely evolve. Assimilation of the large-scale variables together with a few small-scale variables significantly degrades the filter. These results are explained by the spurious correlations that arise from the sampled ensemble covariances. An alternative approach is to combine two different initialization techniques for the slow and fast variables. Here, the fast variables are initialized by restraining the evolution of the ensemble members, using a Newtonian relaxation toward the observed fast variables. Then, the usual ensemble analysis is used to assimilate the large-scale observationsThis study is supported by the Spanish National Science Program under contracts ESP2005–06823-C05 and ESP2007–65667-C04Peer reviewe

Measurement of the Lambda^0_b lifetime in the decay Lambda^0_b -> J/psi Lambda^0 with the D0 Detector

We present measurements of the Lambda^0_b lifetime in the exclusive decay channel Lambda^0_{b}->J/psi Lambda^0, with J/psi to mu+ mu- and Lambda^0 to p pi-, the B^0 lifetime in the decay B^0 -> J/psi K^0_S with J/psi to mu+ mu- and K^0_S to pi+ pi-, and the ratio of these lifetimes. The analysis is based on approximately 250 pb^{-1} of data recorded with the D0 detector in pp(bar) collisions at sqrt{s}=1.96 TeV. The Lambda^0_b lifetime is determined to be tau(Lambda^0_b) = 1.22 +0.22/-0.18 (stat) +/- 0.04 (syst) ps, the B^0 lifetime tau(B^0) = 1.40 +0.11/-0.10 (stat) +/- 0.03 (syst) ps, and the ratio tau(Lambda^0_b)/tau(B^0) = 0.87 +0.17/-0.14 (stat) +/- 0.03 (syst). In contrast with previous measurements using semileptonic decays, this is the first determination of the Lambda^0_b lifetime based on a fully reconstructed decay channel.Comment: 7 pages, 4 figures, Submitted to Physical Review Letters, v2: Added FNAL Pub-numbe

Measurement of the WW production cross section in p anti-p collisions at s**(1/2) = 1.96 TeV

We present a measurement of the W boson pair-production cross section in p anti-p collisions at a center-of-mass energy of sqrt{s}=1.96 TeV. The data, collected with the Run II DO detector, correspond to an integrated luminosity of 224-252 pb^-1 depending on the final state (ee, emu or mumu). We observe 25 candidates with a background expectation of 8.1+/-0.6(stat)+/-0.6(syst)+/-0.5(lum) events. The probability for an upward fluctuation of the background to produce the observed signal is 2.3x10^-7, equivalent to 5.2 standard deviations.The measurement yields a cross section of 13.8+4.3/-3.8(stat)+1.2/-0.9(syst)+/-0.9(lum) pb, in agreement with predictions from the standard model.Comment: submitted to PR

Erratum to Measurement of σ(ppˉ→Z)⋅Br(Z→ττ)\sigma (p \bar p \to Z) \cdot Br(Z \to \tau\tau) at s=\bm{\sqrt{s}=}1.96 TeV, published in Phys. Rev. D {71}, 072004 (2005)

A change in estimated integrated luminosity (from 226 pb$^{-1} to 257 pb$^{-1}$leads to a corrected value for${\sigma (p \bar p \to Z) \cdot}$Br${(Z \to \tau \tau)}$of$209\pm13(stat.)\pm16(syst.)\pm13(lum) pb