arXiv subjects

S. Durand

Publications and source records attributed to S. Durand.

3 recordsLinked to original sources

arXiv2016

Robust Downbeat Tracking Using an Ensemble of Convolutional Networks

In this paper, we present a novel state of the art system for automatic downbeat tracking from music signals. The audio signal is first segmented in frames which are synchronized at the tatum level of the music. We then extract different kind of features based on harmony, melody, rhythm and bass content to feed convolutional neural networks that are adapted to take advantage of each feature characteristics. This ensemble of neural networks is combined to obtain one downbeat likelihood per tatum. The downbeat sequence is finally decoded with a flexible and efficient temporal model which takes advantage of the metrical continuity of a song. We then perform an evaluation of our system on a large base of 9 datasets, compare its performance to 4 other published algorithms and obtain a significant increase of 16.8 percent points compared to the second best system, for altogether a moderate cost in test and training. The influence of each step of the method is studied to show its strengths and shortcomings.

cs.SD↗

arXiv2009

The Expanded Very Large Array

In almost 30 years of operation, the Very Large Array (VLA) has proved to be a remarkably flexible and productive radio telescope. However, the basic capabilities of the VLA have changed little since it was designed. A major expansion utilizing modern technology is currently underway to improve the capabilities of the VLA by at least an order of magnitude in both sensitivity and in frequency coverage. The primary elements of the Expanded Very Large Array (EVLA) project include new or upgraded receivers for continuous frequency coverage from 1 to 50 GHz, new local oscillator, intermediate frequency, and wide bandwidth data transmission systems to carry signals with 16 GHz total bandwidth from each antenna, and a new digital correlator with the capability to process this bandwidth with an unprecedented number of frequency channels for an imaging array. Also included are a new monitor and control system and new software that will provide telescope ease of use. Scheduled for completion in 2012, the EVLA will provide the world research community with a flexible, powerful, general-purpose telescope to address current and future astronomical issues.

astro-ph.IM↗

arXiv1995

The dynamics of planetary nebulae in the Galaxy: evidence for a third integral

We present a dynamical analysis of 673 galactic Planetary Nebulae, using a two-integral axisymmetric model with a Kuzmin-Kutuzov Stäckel potential. The method fits the kinematics to the projected moments of a distribution function, by means of Quadratic Programming. The 2.2 $μ$m COBE brightness map has been used after correction for the interstellar extinction as a projected star counts map in the modeling, because it constitutes a galactic distribution view of evolved red populations which are considered to be the progenitors of PNe. The model we have obtained provides a 2-integral distribution function for the COBE 2.2 $μ$m map, and thus {\it a fortiori} a deprojection of it, which allows moreover the identification of all the major Galactic components. We derive the density laws for them. The projected velocity dispersions are not well fitted though, especially in the disk, which points at the likely presence of a third integral. If this result can be confirmed by additional data, this would mean that for the first time the presence and importance of a third integral on a global scale is demonstrated.

astro-ph↗