22,524 research outputs found
A Monte Carlo Template based analysis for Air-Cherenkov Arrays
We present a high-performance event reconstruction algorithm: an Image
Pixel-wise fit for Atmospheric Cherenkov Telescopes (ImPACT). The
reconstruction algorithm is based around the likelihood fitting of camera pixel
amplitudes to an expected image template. A maximum likelihood fit is performed
to find the best-fit shower parameters. A related reconstruction algorithm has
already been shown to provide significant improvements over traditional
reconstruction for both the CAT and H.E.S.S. experiments. We demonstrate a
significant improvement to the template generation step of the procedure, by
the use of a full Monte Carlo air shower simulation in combination with a
ray-tracing optics simulation to more accurately model the expected camera
images. This reconstruction step is combined with an MVA-based background
rejection.
Examples are shown of the performance of the ImPACT analysis on both
simulated and measured (from a strong VHE source) gamma-ray data from the
H.E.S.S. array, demonstrating an improvement in sensitivity of more than a
factor two in observation time over traditional image moments-fitting methods,
with comparable performance to previous likelihood fitting analyses. ImPACT is
a particularly promising approach for future large arrays such as the Cherenkov
Telescope Array (CTA) due to its improved high-energy performance and
suitability for arrays of mixed telescope types.Comment: 13 pages, 10 figure
Aircraft digital control design methods
Variations in design methods for aircraft digital flight control are evaluated and compared. The methods fall into two categories; those where the design is done in the continuous domain (or s plane) and those where the design is done in the discrete domain (or z plane). Design method fidelity is evaluated by examining closed loop root movement and the frequency response of the discretely controlled continuous aircraft. It was found that all methods provided acceptable performance for sample rates greater than 10 cps except the uncompensated s plane design method which was acceptable above 20 cps. A design procedure based on optimal control methods was proposed that provided the best fidelity at very slow sample rates and required no design iterations for changing sample rates
Learning policies through argumentation-derived evidence (extended abstract)
(c) IFAAMASPublisher PD
Control system designs for the shuttle infrared telescope facility
The Shuttle Infrared Telescope Facility (SIRTF) image motion compensation system is described in detail and performance is analyzed with respect to system noise inputs, environmental disturbances, and error sources such as bending and feedforward scale factor. It is concluded that the SIRTF accuracy and stability requirements can be met with this design
Self-reported pain severity is associated with a history of coronary heart disease
This study was funded by Arthritis Research UK (grant number: 17292).Peer reviewedPublisher PD
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