7,302 research outputs found
Novel insights into the transition form factor
BaBar's observation of significant deviations of the pion transition form
factor (TFF) from the asymptotic expectation with GeV has brought a
serious crisis to a fundamental picture established for such a simplest
system by perturbative QCD, i.e. the dominance of collinear
factorization at high momentum transfers for the pion TFF. We show that
non-factorizable contributions due to open flavors in
could be an important source that contaminates the pQCD asymptotic limit and
causes such deviations with GeV. Within an effective Lagrangian
approach, the non-factorizable amplitudes can be related to intermediate hadron
loops, i.e. and etc, and their corrections to the
and TFFs can be estimated.Comment: Revtex, 6 pages and 4 eps figures; Extended version accepted by Eur.
Phys. J.
Learning to Estimate Driver Drowsiness from Car Acceleration Sensors using Weakly Labeled Data
This paper addresses the learning task of estimating driver drowsiness from
the signals of car acceleration sensors. Since even drivers themselves cannot
perceive their own drowsiness in a timely manner unless they use burdensome
invasive sensors, obtaining labeled training data for each timestamp is not a
realistic goal. To deal with this difficulty, we formulate the task as a weakly
supervised learning. We only need to add labels for each complete trip, not for
every timestamp independently. By assuming that some aspects of driver
drowsiness increase over time due to tiredness, we formulate an algorithm that
can learn from such weakly labeled data. We derive a scalable stochastic
optimization method as a way of implementing the algorithm. Numerical
experiments on real driving datasets demonstrate the advantages of our
algorithm against baseline methods.Comment: Accepted by ICASSP202
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