307,194 research outputs found
Integrated tools for control-system analysis
The basic functions embedded within a user friendly software package (MATRIXx) are used to provide a high level systems approach to the analysis of linear control systems. Various control system analysis configurations are assembled automatically to minimize the amount of work by the user. Interactive decision making is incorporated via menu options and at selected points, such as in the plotting section, by inputting data. There are five evaluations such as the singular value robustness test, singular value loop transfer frequency response, Bode frequency response, steady-state covariance analysis, and closed-loop eigenvalues. Another section describes time response simulations. A time response for random white noise disturbance is available. The configurations and key equations used for each type of analysis, the restrictions that apply, the type of data required, and an example problem are described. One approach for integrating the design and analysis tools is also presented
Operating injection lasers by fast square current pulses of variable amplitude
A simple solid state circuit was used to drive GaAs injection lasers by fast (∼100 nsec) square pulses of variable amplitude (0–25 A). The amplitudes of the current pulses and the corresponding emitted light pulses were measured by a dual peak detector circuit. Using these circuits we were able to plot automatically the current vs light curve and determine the threshold current of the laser diodes
The space physics environment data analysis system (SPEDAS)
With the advent of the Heliophysics/Geospace System Observatory (H/GSO), a complement of multi-spacecraft missions and ground-based observatories to study the space environment, data retrieval, analysis, and visualization of space physics data can be daunting. The Space Physics Environment Data Analysis System (SPEDAS), a grass-roots software development platform (www.spedas.org), is now officially supported by NASA Heliophysics as part of its data environment infrastructure. It serves more than a dozen space missions and ground observatories and can integrate the full complement of past and upcoming space physics missions with minimal resources, following clear, simple, and well-proven guidelines. Free, modular and configurable to the needs of individual missions, it works in both command-line (ideal for experienced users) and Graphical User Interface (GUI) mode (reducing the learning curve for first-time users). Both options have “crib-sheets,” user-command sequences in ASCII format that can facilitate record-and-repeat actions, especially for complex operations and plotting. Crib-sheets enhance scientific interactions, as users can move rapidly and accurately from exchanges of technical information on data processing to efficient discussions regarding data interpretation and science. SPEDAS can readily query and ingest all International Solar Terrestrial Physics (ISTP)-compatible products from the Space Physics Data Facility (SPDF), enabling access to a vast collection of historic and current mission data. The planned incorporation of Heliophysics Application Programmer’s Interface (HAPI) standards will facilitate data ingestion from distributed datasets that adhere to these standards. Although SPEDAS is currently Interactive Data Language (IDL)-based (and interfaces to Java-based tools such as Autoplot), efforts are under-way to expand it further to work with python (first as an interface tool and potentially even receiving an under-the-hood replacement). We review the SPEDAS development history, goals, and current implementation. We explain its “modes of use” with examples geared for users and outline its technical implementation and requirements with software developers in mind. We also describe SPEDAS personnel and software management, interfaces with other organizations, resources and support structure available to the community, and future development plans.Published versio
Level-1 pixel based tracking trigger algorithm for LHC upgrade
The Pixel Detector is the innermost detector of the tracking system of the
Compact Muon Solenoid (CMS) experiment at CERN Large Hadron Collider (LHC). It
precisely determines the interaction point (primary vertex) of the events and
the possible secondary vertexes due to heavy flavours ( and quarks); it
is part of the overall tracking system that allows reconstructing the tracks of
the charged particles in the events and combined with the magnetic field to
measure their impulsion. The pixel detector allows measuring the tracks in the
region closest to the interaction point. The Level-1 (real-time) pixel based
tracking trigger is a novel trigger system that is currently being studied for
the LHC upgrade. An important goal is developing real-time track reconstruction
algorithms able to cope with very high rates and high flux of data in a very
harsh environment. The pixel detector has an especially crucial role in
precisely identifying the primary vertex of the rare physics events from the
large pile-up (PU) of events. The goal of adding the pixel information already
at the real-time level of the selection is to help reducing the total level-1
trigger rate while keeping an high selection capability. This is quite an
innovative and challenging objective for the experiments upgrade for the High
Luminosity LHC (HL-LHC). The special case here addressed is the CMS experiment.
This document describes exercises focusing on the development of a fast pixel
track reconstruction where the pixel track matches with a Level-1 electron
object using a ROOT-based simulation framework.Comment: Submitted to JINST; 12 pages, 10 figures, Contribution to the JINST
proceedings for the INFIERI2014 School in Paris, France, July 14-25, 201
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