210 research outputs found
Advances in Feature Selection with Mutual Information
The selection of features that are relevant for a prediction or
classification problem is an important problem in many domains involving
high-dimensional data. Selecting features helps fighting the curse of
dimensionality, improving the performances of prediction or classification
methods, and interpreting the application. In a nonlinear context, the mutual
information is widely used as relevance criterion for features and sets of
features. Nevertheless, it suffers from at least three major limitations:
mutual information estimators depend on smoothing parameters, there is no
theoretically justified stopping criterion in the feature selection greedy
procedure, and the estimation itself suffers from the curse of dimensionality.
This chapter shows how to deal with these problems. The two first ones are
addressed by using resampling techniques that provide a statistical basis to
select the estimator parameters and to stop the search procedure. The third one
is addressed by modifying the mutual information criterion into a measure of
how features are complementary (and not only informative) for the problem at
hand
Tuberculosis in roe deer from Spain and Italy
TUBERCULOSIS (TB) is a chronic infectious disease caused by bacteria
of the genus Mycobacterium (Grange and others 1990). The detection
of wildlife reservoirs of disease is important, particularly in areas where
there is a relatively low incidence of the disease in domestic animals.
Tuberculosis cases in roe deer (Capreolus capreolus) are reported only
sporadically, despite the wide distribution and the abundance of this cervid.
Roe deer with TB have been reported in Germany (Schmidt 1938),
Switzerland (Bouvier 1963), France (Zanella and others 2008) and the
UK (Gunning 1985, Delahay and others 2007). This short communication
is the first report of TB in roe deer in Spain and Italy, and discusses
the implications of these findings for wildlife and livestock disease control.
The prevalence of mycobacterial infections, such as TB and paratuberculosis,
seems to be increasing in Spain. Wildlife species may act as disease
reservoirs, so this short communication also elucidates the epidemiology
of mycobacterial infections in species such as roe deer
Semantic-Functional Communications in Cyber-Physical Systems
This paper explores the use of semantic knowledge inherent in the
cyber-physical system (CPS) under study in order to minimize the use of
explicit communication, which refers to the use of physical radio resources to
transmit potentially informative data. It is assumed that the acquired data
have a function in the system, usually related to its state estimation, which
may trigger control actions. We propose that a semantic-functional approach can
leverage the semantic-enabled implicit communication while guaranteeing that
the system maintains functionality under the required performance. We
illustrate the potential of this proposal through simulations of a swarm of
drones jointly performing remote sensing in a given area. Our numerical results
demonstrate that the proposed method offers the best design option regarding
the ability to accomplish a previously established task -- remote sensing in
the addressed case -- while minimising the use of radio resources by
controlling the trade-offs that jointly determine the CPS performance and its
effectiveness in the use of resources. In this sense, we establish a
fundamental relationship between energy, communication, and functionality
considering a given end application
Higgs Interference Effects in \Pg \Pg \to \PZ\PZ and their Uncertainty
Interference between the Standard Model Higgs boson and continuum
contributions is considered in the heavy-mass scenario. Results are available
at leading order for the background. It is discussed how to combine the result
with the next-to-next-to-leading order Higgs production cross-section and a
proposal for estimating the associated theoretical uncertainty is presented.Comment: 25 pages, 10 figures; improved numerical accuracy, Numerics updated,
conclusions unchanged, references added. v
Inadequacy of zero-width approximation for a light Higgs boson signal
In the Higgs search at the LHC, a light Higgs boson (115 GeV <~ M_H <~ 130
GeV) is not excluded by experimental data. In this mass range, the width of the
Standard Model Higgs boson is more than four orders of magnitude smaller than
its mass. The zero-width approximation is hence expected to be an excellent
approximation. We show that this is not always the case. The inclusion of
off-shell contributions is essential to obtain an accurate Higgs signal
normalisation at the 1% precision level. For gg (-> H) -> VV, V= W,Z, O(10%)
corrections occur due to an enhanced Higgs signal in the region M_VV > 2 M_V,
where also sizable Higgs-continuum interference occurs. We discuss how
experimental selection cuts can be used to exclude this region in search
channels where the Higgs invariant mass cannot be reconstructed. We note that
the H -> VV decay modes in weak boson fusion are similarly affected.Comment: 26 pages, 18 figures, 6 tables; added references, expanded
introduction, version to appear in JHE
Epidémie d'hépatite A aiguë parmi des hommes ayant des rapports sexuels avec des hommes (HSH) Caractéristiques cliniques et épidémiologiques des cas diagnostiqués au CHU de Rouen
International audienc
Heavy Higgs signal-background interference in gg → VV in the Standard Model plus real singlet
For the Standard Model extended with a real scalar singlet field, the
modification of the heavy Higgs signal due to interference with the continuum
background and the off-shell light Higgs contribution is studied for gg --> ZZ,
WW --> 4 lepton processes at the Large Hadron Collider. Interference effects
can range from O(10%) to O(1) effects for integrated cross sections. Despite a
strong cancellation between the heavy Higgs-continuum and the heavy Higgs-light
Higgs interference, the full interference is clearly non-negligible and
modifies the heavy Higgs line shape. A |M_VV - M_h2| < Gamma_h2 cut mitigates
interference effects to O(10%) or less. A public program that allows to
simulate the full interference is presented.Comment: 22 pages, 15 figures, 9 tables; added results and references,
improved discussion, corrected v2 results (heavy top approximation was
inadvertently active, results deviate by less than 5%), conclusions
unchanged, updated gg2VV code, version to appear in EPJ
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