22,234 research outputs found
Web based system architecture for long pulse remote experimentation
Remote experimentation (RE) methods will be essential in next generation fusion devices. Requirements for long pulse RE will be: on-line data visualization, on-line data acquisition processes monitoring and on-line data acquisition systems interactions (start, stop or set-up modifications). Note that these methods are not oriented to real-time control of fusion plant devices.
INDRA Sistemas S.A., CIEMAT (Centro de Investigaciones Energéticas Medioambientales y Tecnológicas) and UPM (Universidad Politécnica de Madrid) have designed a specific software architecture for these purposes. The architecture can be supported on the BeansNet platform, whose integration with an application server provides an adequate solution to the requirements. BeansNet is a JINI based framework developed by INDRA, which makes easy the implementation of a remote experimentation model based on a Service Oriented Architecture. The new software architecture has been designed on the basis of the experience acquired in the development of an upgrade of the TJ-II remote experimentation system
Fuzzy Inference System for VOLT/VAR control in distribution substations in isolated power systems
This paper presents a fuzzy inference system for voltage/reactive power
control in distribution substations. The purpose is go forward to automation
distribution and its implementation in isolated power systems where control
capabilities are limited and it is common using the same applications as in
continental power systems. This means that lot of functionalities do not apply
and computational burden generates high response times. A fuzzy controller,
with logic guidelines embedded based upon heuristic rules resulting from
operators at dispatch control center past experience, has been designed.
Working as an on-line tool, it has been tested under real conditions and it has
managed the operation during a whole day in a distribution substation. Within
the limits of control capabilities of the system, the controller maintained
successfully an acceptable voltage profile, power factor values over 0,98 and
it has ostensibly improved the performance given by an optimal power flow based
automation system
Nuclear physics in soft-wall AdS/QCD: Deuteron electromagnetic form factors
We present a high-quality description of the deuteron electromagnetic form
factors in a soft-wall AdS/QCD approach. We first propose an effective action
describing the dynamics of the deuteron in the presence of an external vector
field. Based on this action the deuteron electromagnetic form factors are
calculated, displaying the correct 1/Q^10 power scaling for large Q^2 values.
This finding is consistent with quark counting rules and the earlier
observation that this result holds in confining gauge/gravity duals. The Q^2
dependence of the deuteron form factors is defined by a single and universal
scale parameter kappa, which is fixed from data.Comment: 6 page
Nucleon resonances in AdS/QCD
We describe the electroproduction of the N(1440) Roper resonance in soft-wall
AdS/QCD. The Roper resonance is identified as the first radially excited state
of the nucleon, where higher-Fock states in addition to the three-quark
component are included. The main conclusion is that the leading 3q component
plays the dominant role in the description of electroproduction properties of
this resonance: form factors, helicity amplitudes and charge densities. The
obtained results are in good agreement with the recent results of the CLAS
Collaboration at JLab.Comment: 20 pages. arXiv admin note: text overlap with arXiv:1204.661
Data reduction in the ITMS system through a data acquisition model with self-adaptive sampling rate
Long pulse or steady state operation of fusion experiments require data acquisition and processing systems that reduce the volume of data involved. The availability of self-adaptive sampling rate systems and the use of real-time lossless data compression techniques can help solve these problems. The former is important for continuous adaptation of sampling frequency for experimental requirements. The latter allows the maintenance of continuous digitization under limited memory conditions. This can be achieved by permanent transmission of compressed data to other systems. The compacted transfer ensures the use of minimum bandwidth. This paper presents an implementation based on intelligent test and measurement system (ITMS), a data acquisition system architecture with multiprocessing capabilities that permits it to adapt the system’s sampling frequency throughout the experiment. The sampling rate can be controlled depending on the experiment’s specific requirements by using an external dc voltage signal or by defining user events through software. The system takes advantage of the high processing capabilities of the ITMS platform to implement a data reduction mechanism based in lossless data compression algorithms which are themselves based in periodic deltas
Mapping the galaxy NGC 4486 (M87) through its Globular Cluster System
As shown in previous works, globular clusters can be used to trace the
overall structure of the diffuse stellar populations in early type galaxies if
the number of clusters per unit stellar mass depends on metallicity. In this
paper we further test this assumption in the galaxy NGC 4486 (M 87), by
combining several data sources. The results show that globular clusters allow
the mapping of the galaxy in terms of the surface brightness profile,
integrated colour gradient, chemical abundance, and mass to luminosity ratios
up to 1000 arcsec (or 80.4 kpc) from its centre (i.e. some 10 effective radii).
The analysis indicates the presence of a dominant high metallicity bulge
associated with the red globulars, whose ellipticity increases outwards, and of
a more flattened low metallicity halo connected with the blue globulars. The
chemical abundance gradient of the composite stellar population is remarkably
similar to that inferred from X ray observations of hot gas. The
mass-metallicity spectrum of the stellar population can, in principle, be
understood in terms of inhomogeneous enrichment models. In turn, the
distribution of the bluest GCs, and lowest metallicity halo stars, has an
intriguing similarity with that of dark matter, a feature shared with NGC 1399.
Also, in these two galaxies, the number of blue GCs per dark mass unit is
identical within the errors, \approx 1.0(\pm0.3) \times 10^{-9} . The total
stellar mass derived for NGC 4486 is 6.8(\pm1.1) \times 10^{11} M\odot with a
baryonic mass fraction fb = 0.08(\pm 0.01).Comment: 18 pages, 23 figure
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