Attendance to Massive Open On-line Courses: Towards a Solution to Track on-line Recorded Lectures Viewing

Massive open on-line courses (MOOC) suchas those by edX.org are digital courses where thousands students are dispersed across the Internet. This new variant for distance learning opens many new challenges including the need to verify the real vision of recorded lectures same as we control the physical presence of scholars in a traditional classroom. We review here a precursor study on the effectiveness of the new Pinvox system (i.e., “Personal Identification Number by Voice”), that aims to ensure“on-line attendance”by confirming that a particular student has actually listened to and watched a complete video lecture

Gas Pixel Detectors for X-ray Polarimetry applications

We discuss a new class of Micro Pattern Gas Detectors, the Gas Pixel Detector (GPD), in which a complete integration between the gas amplification structure and the read-out electronics has been reached. An Application-Specific Integrated Circuit (ASIC) built in deep sub-micron technology has been developed to realize a monolithic device that is, at the same time, the pixelized charge collecting electrode and the amplifying, shaping and charge measuring front-end electronics. The CMOS chip has the top metal layer patterned in a matrix of 80 micron pitch hexagonal pixels, each of them directly connected to the underneath electronics chain which has been realized in the remaining five layers of the 0.35 micron VLSI technology. Results from tests of a first prototype of such detector with 2k pixels and a full scale version with 22k pixels are presented. The application of this device for Astronomical X-Ray Polarimetry is discussed. The experimental detector response to polarized and unpolarized X-ray radiation is shown. Results from a full MonteCarlo simulation for two astronomical sources, the Crab Nebula and the Hercules X1, are also reported.Comment: 16 pages, 20 figures, accepted for publication in Nuclear Instruments and Methods in Physics Research Section

The On-orbit Calibrations for the Fermi Large Area Telescope

The Large Area Telescope (LAT) on--board the Fermi Gamma ray Space Telescope began its on--orbit operations on June 23, 2008. Calibrations, defined in a generic sense, correspond to synchronization of trigger signals, optimization of delays for latching data, determination of detector thresholds, gains and responses, evaluation of the perimeter of the South Atlantic Anomaly (SAA), measurements of live time, of absolute time, and internal and spacecraft boresight alignments. Here we describe on orbit calibration results obtained using known astrophysical sources, galactic cosmic rays, and charge injection into the front-end electronics of each detector. Instrument response functions will be described in a separate publication. This paper demonstrates the stability of calibrations and describes minor changes observed since launch. These results have been used to calibrate the LAT datasets to be publicly released in August 2009.Comment: 60 pages, 34 figures, submitted to Astroparticle Physic

Design and implementation of a high-quality, low-power deinterlacer circuit

A novel circuit for a simple non motion-compensated deinterlacer is presented, where a motion detection module effectively computes a weighted mean of a temporal and a spatial interpolator. Both the motion detection module and the two interpolators are innovative, simple and effective, so that they are able to provide very good results, as experimental results show, at a low computational complexity. The final circuit, based on a pipeline architecture, has been designed to work on a real time video digital signal with a low power consumption