4,244 research outputs found
Statistical performance analysis of a fast super-resolution technique using noisy translations
It is well known that the registration process is a key step for
super-resolution reconstruction. In this work, we propose to use a
piezoelectric system that is easily adaptable on all microscopes and telescopes
for controlling accurately their motion (down to nanometers) and therefore
acquiring multiple images of the same scene at different controlled positions.
Then a fast super-resolution algorithm \cite{eh01} can be used for efficient
super-resolution reconstruction. In this case, the optimal use of images
for a resolution enhancement factor is generally not enough to obtain
satisfying results due to the random inaccuracy of the positioning system. Thus
we propose to take several images around each reference position. We study the
error produced by the super-resolution algorithm due to spatial uncertainty as
a function of the number of images per position. We obtain a lower bound on the
number of images that is necessary to ensure a given error upper bound with
probability higher than some desired confidence level.Comment: 15 pages, submitte
Almost sure existence of global weak solutions for super-critical Navier-Stokes equations
In this paper we show that after suitable data randomization there exists a
large set of super-critical periodic initial data, in for some , for both 2d and 3d Navier-Stokes equations for
which global energy bounds are proved. As a consequence, we obtain almost sure
super-critical global weak solutions. We also show that in 2d these global weak
solutions are unique.Comment: 22 pages, a revised argument in Section 5, the cas
Existence of Weak Solutions for the Incompressible Euler Equations
Using a recent result of C. De Lellis and L. Sz\'{e}kelyhidi Jr. we show
that, in the case of periodic boundary conditions and for dimension greater or
equal 2, there exist infinitely many global weak solutions to the
incompressible Euler equations with initial data , where may be any
solenoidal -vectorfield. In addition, the energy of these solutions is
bounded in time.Comment: 5 page
Probabilistic Relational Model Benchmark Generation
The validation of any database mining methodology goes through an evaluation
process where benchmarks availability is essential. In this paper, we aim to
randomly generate relational database benchmarks that allow to check
probabilistic dependencies among the attributes. We are particularly interested
in Probabilistic Relational Models (PRMs), which extend Bayesian Networks (BNs)
to a relational data mining context and enable effective and robust reasoning
over relational data. Even though a panoply of works have focused, separately ,
on the generation of random Bayesian networks and relational databases, no work
has been identified for PRMs on that track. This paper provides an algorithmic
approach for generating random PRMs from scratch to fill this gap. The proposed
method allows to generate PRMs as well as synthetic relational data from a
randomly generated relational schema and a random set of probabilistic
dependencies. This can be of interest not only for machine learning researchers
to evaluate their proposals in a common framework, but also for databases
designers to evaluate the effectiveness of the components of a database
management system
A comparison of the predictions of a finite element model and multiscale model for a rough MEMS electrical contact
Rough surface contact is difficult to model effectively due to multiple scales of detail that need to be considered. This work presents the results of a multiscale rough surface contact model in comparison to a finite element based deterministic model for the electrical contact of a MEMS microswitch. The real area of contact and electrical contact resistance are predicted and compared as a function of normal load. The results show good quantitative and qualitative correlation between the two methods. As expected, the contact area increases nominally linearly with load, while the contact resistance decreases with load. It is notable though that the contact pressure is up to 16% higher than the hardness (2.8 times yield strength), and could be even higher for other surfaces
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