10,548 research outputs found
Event Recognition Using Signal Spectrograms in Long Pulse Experiments
As discharge duration increases, real-time complex analysis of the signal becomes more important. In this context, data acquisition and processing systems must provide models for designing experiments which use event oriented plasma control. One example of advanced data analysis is signal classification. The off-line statistical analysis of a large number of discharges provides information to develop algorithms for the determination of the plasma parameters from measurements of magnetohydrodinamic waves, for example, to detect density fluctuations induced by the Alfvén cascades using morphological patterns. The need to apply different algorithms to the signals and to address different processing algorithms using the previous results necessitates the use of an event-based experiment. The Intelligent Test and Measurement System platform is an example of architecture designed to implement distributed data acquisition and real-time processing systems. The processing algorithm sequence is modeled using an event-based paradigm. The adaptive capacity of this model is based on the logic defined by the use of state machines in SCXML. The Intelligent Test and Measurement System platform mixes a local multiprocessing model with a distributed deployment of services based on Jini
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
String Driven Cosmology and its Predictions
We present a minimal model for the Universe evolution fully extracted from
effective String Theory. This model is by its construction close to the
standard cosmological evolution, and it is driven selfconsistently by the
evolution of the string equation of state itself. The inflationary String
Driven stage is able to reach enough inflation, describing a Big Bang like
evolution for the metric. By linking this model to a minimal but well
established observational information, (the transition times of the different
cosmological epochs), we prove that it gives realistic predictions on early and
current energy density and its results are compatible with General Relativity.
Interestingly enough, the predicted current energy density is found Omega = 1
and a lower limit Omega \geq 4/9 is also found. The energy density at the exit
of the inflationary stage also gives | Omega |_{inf}=1. This result shows an
agreement with General Relativity (spatially flat metric gives critical energy
density) within an inequivalent Non-Einstenian context (string low energy
effective equations). The order of magnitude of the energy density-dilaton
coupled term at the beginning of the radiation dominated stage agrees with the
GUT scale. The predicted graviton spectrum is computed and analyzed without any
free parameters. Peaks and asymptotic behaviours of the spectrum are a direct
consequence of the dilaton involved and not only of the scale factor evolution.
Drastic changes are found at high frequencies: the dilaton produces an
increasing spectrum (in no string cosmologies the spectrum is decreasing).
Without solving the known problems about higher order corrections and graceful
exit of inflation, we find this model closer to the observational Universe than
the current available string cosmology scenarii.Comment: LaTex, 22 pages, Lectures delivered at the Chalonge School, Nato ASI:
Phase Transitions in the Early Universe: Theory and Observations. To appear
in the Proceedings, Editors H. J. de Vega, I. Khalatnikov, N. Sanchez.
(Kluwer Pub
Highlights and Conclusions of the Chalonge 14th Paris Cosmology Colloquium 2010: `The Standard Model of the Universe: Theory and Observations'
The Chalonge 14th Paris Cosmology Colloquium was held on 22-24 July 2010 in
Paris Observatory on the Standard Model of the Universe: News from WMAP7,
BICEP, QUAD, SPT, AMI, ACT, Planck, QUIJOTE and Herschel; dark matter (DM)
searches and galactic observations; related theory and simulations. %aiming
synthesis, progress and clarification. P Biermann, D Boyanovsky, A Cooray, C
Destri, H de Vega, G Gilmore, S Gottlober, E Komatsu, S McGaugh, A Lasenby, R
Rebolo, P Salucci, N Sanchez and A Tikhonov present here their highlights of
the Colloquium. Inflection points emerged: LambdaWDM (Warm DM) emerges
impressively over LambdaCDM whose galactic scale problems are ever-increasing.
Summary and conclusions by H. J. de Vega, M. C. Falvella and N. G. Sanchez
stress among other points: (i) Primordial CMB gaussianity is confirmed.
Inflation effective theory predicts a tensor to scalar ratio 0.05-0.04 at
reach/border line of next CMB observations, early fast-roll inflation provides
lowest multipoles depression. SZ amplitudes are smaller than expected: CMB and
X-ray data agree but intracluster models need revision and relaxed/non-relaxed
clusters distinction. (ii) cosmic ray positron excess is explained naturally by
astrophysical processes, annihilating/decaying dark matter needs growing
tailoring. (iii) Cored (non cusped) DM halos and warm (keV scale mass) DM are
increasingly favored from theory and observations, naturally producing observed
small scale structures, wimps turn strongly disfavoured. LambdaWDM 1 keV
simulations well reproduce observations. Evidence that LambdaCDM does not work
at small scales is staggering. P Biermann presents his live minutes of the
Colloquium and concludes that a keV sterile neutrino is the most interesting DM
candidate. Photos of the Colloquium are included.Comment: 58 pages, 20 figures. Three contributions added: G. Gilmore, S.
Gottlober and E. Komats
Strings in Cosmological and Black Hole Backgrounds: Ring Solutions
The string equations of motion and constraints are solved for a ring shaped
Ansatz in cosmological and black hole spacetimes. In FRW universes with
arbitrary power behavior [R(X^0) = a\;|X^0|^{\a}\, ], the asymptotic form of
the solution is found for both and and we plot the
numerical solution for all times. Right after the big bang (), the
string energy decreasess as and the string size grows as for . Very
soon [ ] , the ring reaches its oscillatory regime with frequency
equal to the winding and constant size and energy. This picture holds for all
values of \a including string vacua (for which, asymptotically, \a = 1).
In addition, an exact non-oscillatory ring solution is found. For black hole
spacetimes (Schwarzschild, Reissner-Nordstr\oo m and stringy), we solve for
ring strings moving towards the center. Depending on their initial conditions
(essentially the oscillation phase), they are are absorbed or not by
Schwarzschild black holes. The phenomenon of particle transmutation is
explicitly observed (for rings not swallowed by the hole). An effective horizon
is noticed for the rings. Exact and explicit ring solutions inside the
horizon(s) are found. They may be interpreted as strings propagating between
the different universes described by the full black hole manifold.Comment: Paris preprint PAR-LPTHE-93/43. Uses phyzzx. Includes figures. Text
and figures compressed using uufile
Towards the Chalonge 17th Paris Cosmology Colloquium 2013: highlights and conclusions of the Chalonge 16th Paris Cosmology Colloquium 2012
LWDM (Warm Dark Matter) is progressing impressively.The galactic scale crisis
and decline of LCDM+baryons are staggering. The 16th Paris Chalonge Colloquium
2012 combined real cosmological/astrophysical data and hard theory predictive
approach in the LWDM Standard Model. News and reviews from
ACT,WMAP,SPT,QUIET,Planck,Herschel,JWST,UFFO,KATRIN and MARE experiments;
astrophysics, particle and nuclear physics WDM searches, galactic observations,
related theory and simulations, with the aim of synthesis and clarification.
Here highlights by P Biermann, C Burigana, C Conselice, A Cooray, H de Vega, C
Giunti & M Laveder, J Kormendi & K Freeman, E Ma, J Mather, L Page, G Smoot, N
Sanchez. Summary and conclusions by de Vega, Falvella and Sanchez. Data confirm
primordial CMB gaussianity. Effective (Ginsburg-Landau) Inflation theory
predicts r about 0.04-0.05, negligeable running of ns, the inflation energy
scale (GUT scale) and the set of CMB observables in agreement with the data.
WMAP9 and Planck measurements are compatible with one or two Majorana sterile
neutrinos in the eV mass scale. Cored (non cusped) DM halos and keV WDM are
strongly favored by theory and observations, Wimps are strongly disfavoured.
LambdaCDM with baryons do not work at small scales. Inside galaxy cores,
quantum WDM effects are important. Quantum WDM calculations (Thomas-Fermi)
provide galaxy masses, velocity dispersions and cored profiles and their sizes
in agreement with observations. A WDM fermion of about 2 keV naturally
reproduces galaxy, large scale and cosmological observations. WDM keV particles
deserve dedicated astronomical and laboratory searches, theoretical work and
numerical simulations. KATRIN can be adapted to look to keV scale sterile
neutrinos. It will be a fantastic discovery to detect dark matter in beta
decay. Photos of the Colloquium are includedComment: 58 pages, 15 figures. arXiv admin note: substantial text overlap with
arXiv:1203.3562, arXiv:1305.7452, arXiv:1009.3494, arXiv:1304.075
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