Optimal dyadic decision trees

We introduce a novel algorithm for building an optimal dyadic decision tree (ODT). The method combines guaranteed performance in the learning theoretical sense and optimal search from the algorithmic point of view. Furthermore it inherits the explanatory power of tree approaches, while improving performance over classical approaches such as CART/C4.5, as shown on experiments on artificial and benchmark data

CHAMP+: A powerful submm Heterodyne Array

To make best use of the exceptional good weather conditions at Chajnantor we developed CHAMP+, a two time seven pixel dual-color heterodyne array for operation in the 350 and 450 µm atmospheric windows. CHAMP+ uses state-of-the-art SIS-mixers provided by our collaborators at SRON. To maximize its performance, optical single sideband filter are implemented for each of the two subarrays, and most of the optics is operated cold (20K) to minimize noise contributions. The instrument can be operated remotely, under full computer control of all components. The autocorrelator backend, currently in operation with 2 × 1GHz of bandwidth for each of the 14 heterodyne channels, will be upgraded by a new technologies FFT spectrometer array in mid 2008. CHAMP+ has been commissioned successfully in late 2007. We will review the performance of the instrument "in the field," and present its characteristics as measured on-sky