1,657,664 research outputs found
DEPASCALISATION OF SMARANDACHE PASCAL DERIVED SEQUENCES AND BACKWARD EXTENDED FIBONACCI SEQUENCE
We call the process of extracting the base sequence from the Pascal derived sequence as Depascalisation. The interesting observation is that this again involves the Pascal's triangle though with a difference
Reconciling Mass Functions with the Star-Forming Main Sequence Via Mergers
We combine star formation along the `main sequence', quiescence, and
clustering and merging to produce an empirical model for the evolution of
individual galaxies. Main sequence star formation alone would significantly
steepen the stellar mass function towards low redshift, in sharp conflict with
observation. However, a combination of star formation and merging produces a
consistent result for correct choice of the merger rate function. As a result,
we are motivated to propose a model in which hierarchical merging is
disconnected from environmentally-independent star formation. This model can be
tested via correlation functions and would produce new constraints on
clustering and merging.Comment: MNRAS, in pres
Photon locking
A novel observation of photon locking—the optical analog of spin locking—is reported, demonstrating the applicability of phase-coherent pulse sequences. The experiments are reported for the optical transition of iodine gas at 589.7 nm using the pulse sequence XYX-XYX̄. Locking decay rates are presented as a function of pressure and compared with optical dephasing (echo-decay) rates
The lower main sequence of stars in the solar neighborhood: Model predictions versus observation
We have used the Simbad database and VizieR catalogue access tools to
construct the observational color-absolute magnitude diagrams of nearby K-M
dwarfs with precise Hipparcos parallaxes (\sigma_\pi/\pi < 0.05). Particular
attention has been paid to removing unresolved double/multiple and variable
stars. In addition to archival data, we have made use of nearly 2000 new
radial-velocity measurements of K-M dwarfs to identify spectroscopic binary
candidates. The main sequences, cleaned from unresolved binaries, variable
stars, and old population stars which can also widen the sequence due to their
presumably lower metallicity, were compared to available solar-metallicity
models. Significant ofsets of most of the model main-sequence lines are seen
with respect to observational data, especially for the lower-mass stars. Only
the location and slope of the Victoria-Regina and, partly, BaSTI isochrones
match the data quite well.Comment: Submitted to JENAM-2011 SpS3 (Saint Petersburg, July 4-8, 2011)
Proceeding
Sequential joint signal detection and signal-to-noise ratio estimation
The sequential analysis of the problem of joint signal detection and
signal-to-noise ratio (SNR) estimation for a linear Gaussian observation model
is considered. The problem is posed as an optimization setup where the goal is
to minimize the number of samples required to achieve the desired (i) type I
and type II error probabilities and (ii) mean squared error performance. This
optimization problem is reduced to a more tractable formulation by transforming
the observed signal and noise sequences to a single sequence of Bernoulli
random variables; joint detection and estimation is then performed on the
Bernoulli sequence. This transformation renders the problem easily solvable,
and results in a computationally simpler sufficient statistic compared to the
one based on the (untransformed) observation sequences. Experimental results
demonstrate the advantages of the proposed method, making it feasible for
applications having strict constraints on data storage and computation.Comment: 5 pages, Proceedings of IEEE International Conference on Acoustics,
Speech, and Signal Processing (ICASSP), 201
An Improved Observation Model for Super-Resolution under Affine Motion
Super-resolution (SR) techniques make use of subpixel shifts between frames
in an image sequence to yield higher-resolution images. We propose an original
observation model devoted to the case of non isometric inter-frame motion as
required, for instance, in the context of airborne imaging sensors. First, we
describe how the main observation models used in the SR literature deal with
motion, and we explain why they are not suited for non isometric motion. Then,
we propose an extension of the observation model by Elad and Feuer adapted to
affine motion. This model is based on a decomposition of affine transforms into
successive shear transforms, each one efficiently implemented by row-by-row or
column-by-column 1-D affine transforms.
We demonstrate on synthetic and real sequences that our observation model
incorporated in a SR reconstruction technique leads to better results in the
case of variable scale motions and it provides equivalent results in the case
of isometric motions
- …
