5 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
JEM-X: The X-ray monitor aboard INTEGRAL
The JEM–X monitor provides X-ray spectra and imaging with
arcminute angular resolution in the 3 to 35 keV band. The good
angular resolution and the low energy response of JEM–X plays an
important role in the identification of gamma ray sources and
in the analysis and scientific interpretation of the combined
X-ray and gamma ray data.
JEM–X is a coded aperture instrument consisting of two identical,
coaligned telescopes. Each of the detectors has a sensitive area
of 500Â cm2, and views the sky through its own coded aperture
mask. The two coded masks are inverted with respect to each other and
provides an angular resolution of 3'Â across an effective
field of view of about 10° diameter