10,539 research outputs found
Compressive Pattern Matching on Multispectral Data
We introduce a new constrained minimization problem that performs template
and pattern detection on a multispectral image in a compressive sensing
context. We use an original minimization problem from Guo and Osher that uses
minimization techniques to perform template detection in a multispectral
image. We first adapt this minimization problem to work with compressive
sensing data. Then we extend it to perform pattern detection using a formal
transform called the spectralization along a pattern. That extension brings out
the problem of measurement reconstruction. We introduce shifted measurements
that allow us to reconstruct all the measurement with a small overhead and we
give an optimality constraint for simple patterns. We present numerical results
showing the performances of the original minimization problem and the
compressed ones with different measurement rates and applied on remotely sensed
data.Comment: Published in IEEE Transactions on Geoscience and Remote Sensin
Propositions pour la masterisation
Sans porter de jugement sur la réforme de masterisation de la formation des maîtres en cours, cette libre opinion, s\u27appuyant sur des enquêtes menées à l\u27échelle locale et nationale, propose des outils de travail collaboratif pour rompre avec la taylorisation des tâches entre les différents acteurs de la formation des maîtres (universités, IUFM, rectorat, établissements du secondaire) et tendre vers une logique de réseau de contribution
Polaron relaxation in ferroelectric thin films
We report a dielectric relaxation in ferroelectric thin films of the ABO3
family. We have compared films of different compositions with several growth
modes: sputtering (with and without magnetron) and sol-gel. The relaxation was
observed at cryogenic temperature (T<100K) for frequencies from 100Hz up to
10MHz. This relaxation activation energy is always lower than 200meV. It is
very similar to the polaron relaxation that we reported in the parent bulk
perovskites. Being independent of the materials size, morphology and texture,
this relaxation can be a useful probe of defects in actual integrated
capacitors with no need for specific shapin
Optimized Confinement of Fermions in Two Dimensions
One of the challenging features of studying model Hamiltonians with cold
atoms in optical lattices is the presence of spatial inhomogeneities induced by
the confining potential, which results in the coexistence of different phases.
This paper presents Quantum Monte Carlo results comparing meth- ods for
confining fermions in two dimensions, including conventional diagonal
confinement (DC), a recently proposed 'off-diagonal confinement' (ODC), as well
as a trap which produces uniform den- sity in the lattice. At constant entropy
and for currently accessible temperatures, we show that the current DC method
results in the strongest magnetic signature, primarily because of its judicious
use of entropy sinks at the lattice edge. For d-wave pairing, we show that a
constant density trap has the more robust signal and that ODC can implement a
constant density profile. This feature is important to any prospective search
for superconductivity in optical lattices
The population of deformed bands in Cr by emission of Be from the S + Mg reaction
Using particle- coincidences we have studied the population of final
states after the emission of 2 -particles and of Be in nuclei
formed in S+Mg reactions at an energy of . The data were obtained in a setup
consisting of the GASP -ray detection array and the multidetector array
ISIS. Particle identification is obtained from the E and E signals of
the ISIS silicon detector telescopes, the Be being identified by the
instantaneous pile up of the E and E pulses. -ray decays of the
Cr nucleus are identified with coincidences set on 2 -particles
and on Be. Some transitions of the side-band with show
stronger population for Be emission relative to that of 2
-particles (by a factor ). This observation is interpreted as
due to an enhanced emission of Be into a more deformed nucleus.
Calculations based on the extended Hauser-Feshbach compound decay formalism
confirm this observation quantitatively.Comment: 17 pages, 9 figures accepted for publication in J. Phys.
Data augmentation from RGB to chlorophyll fluorescence imaging Application to leaf segmentation of Arabidopsis thaliana from top view images
Résumé en françai
Harold Jeffreys's Theory of Probability Revisited
Published exactly seventy years ago, Jeffreys's Theory of Probability (1939)
has had a unique impact on the Bayesian community and is now considered to be
one of the main classics in Bayesian Statistics as well as the initiator of the
objective Bayes school. In particular, its advances on the derivation of
noninformative priors as well as on the scaling of Bayes factors have had a
lasting impact on the field. However, the book reflects the characteristics of
the time, especially in terms of mathematical rigor. In this paper we point out
the fundamental aspects of this reference work, especially the thorough
coverage of testing problems and the construction of both estimation and
testing noninformative priors based on functional divergences. Our major aim
here is to help modern readers in navigating in this difficult text and in
concentrating on passages that are still relevant today.Comment: This paper commented in: [arXiv:1001.2967], [arXiv:1001.2968],
[arXiv:1001.2970], [arXiv:1001.2975], [arXiv:1001.2985], [arXiv:1001.3073].
Rejoinder in [arXiv:0909.1008]. Published in at
http://dx.doi.org/10.1214/09-STS284 the Statistical Science
(http://www.imstat.org/sts/) by the Institute of Mathematical Statistics
(http://www.imstat.org
LANDSAT-D investigations in snow hydrology
Work undertaken during the contract and its results are described. Many of the results from this investigation are available in journal or conference proceedings literature - published, accepted for publication, or submitted for publication. For these the reference and the abstract are given. Those results that have not yet been submitted separately for publication are described in detail. Accomplishments during the contract period are summarized as follows: (1) analysis of the snow reflectance characteristics of the LANDSAT Thematic Mapper, including spectral suitability, dynamic range, and spectral resolution; (2) development of a variety of atmospheric models for use with LANDSAT Thematic Mapper data. These include a simple but fast two-stream approximation for inhomogeneous atmospheres over irregular surfaces, and a doubling model for calculation of the angular distribution of spectral radiance at any level in an plane-parallel atmosphere; (3) incorporation of digital elevation data into the atmospheric models and into the analysis of the satellite data; and (4) textural analysis of the spatial distribution of snow cover
Low-cost image annotation for supervised machine learning. Application to the detection of weeds in dense culture
An open problem in robotized agriculture is to detect weeds in dense culture. This problem can be addressed with computer vision and machine learning. The bottleneck of supervised approaches lay in the manual annotation of training images. We propose two different approaches for detecting weeds position to speed up this process. The first approach is using synthetic images and eye-tracking to annotated images [4] which is at least 30 times faster than manual annotation by an expert, the second approach is based on real RGB and depth images collected via Kinect v2 sensor.
We generated a data set of 150 synthetic images which weeds were randomly positioned on it. Images were gazed by two observers. Eye tracker sampled eye position during the execution of this task [5, 6]. Area of interest was recorded as rectangular patches. A patch is considered as including weeds if the average fixation time in this patch exceeds 1.04 seconds. The quality of visual annotation by eye-tracking is assessed by two ways. First, direct comparison of visual annotation with ground-truth which is shown an average 94.7% of all fixations on an image which fell within ground-truth bounding-boxes. Second, as shown in fig.1 eye-tracked annotated data is used as a training data set in four machine learning approaches and compare the recognition rate with the ground-truth.
These four machine learning methods are tested in order to assess the quality of the visual annotation. These methods correspond to handcrafted features adapted to texture characterization. They are followed by a linear support vector machine binary classifier. The table 1 gives the average accuracy and standard deviation. Experimental results prove that visual eye-tracked annotated data are almost the same as in-silico ground-truth and performances of supervised machine learning on eye-tracked annotated data are very close to the one obtained with ground-truth
Information search and media usage amongst adolescent Sowetons
This study investigates the buying behaviour of black adolescents in Soweto, with the aim of uncovering underlying trends which may be characteristic of other urban black teenagers. Specific objectives included investigating information search and media usage for confectionery products amongst black adolescents in Soweto. Data were gathered from a sample of 641 school children by means of administered questionnaires. Results indicate that urban black adolescents are relatively sophisticated consumers giving preference to consumer-dominated information sources (friends) though market-dominated sources (T.V. advertising) were also regarded as important. The findings also highlight the potential power of the influence of opinion leaders on adolescent buying behaviour as well as the importance of reaching them in advertising campaigns.
Opsomming
Hierdie studie ondersoek die koopgedrag van Swart adolessente in Soweto ten einde onderliggende tendense wat verteenwoordigend van ander Swart stedelike tieners mag wees, te identifiseer. Spesifieke doelstellings sluit in die ondersoek van inligtinginwinningsaktiwiteite en mediagebruik by lekkergoedaankope onder Swart adolessente in Soweto. Data is ingewin van 'n steekproef van 641 skoliere met behulp van vraelyste. Bevindinge toon dat stedelike Swart adolessente relatief gesofistikeerde verbruikers is wat voorkeur verleen aan verbruikersdominante inligtingsbronne (vriende) hoewel markdominante bronne (T.V. advertensies) ook ‘n belangrike rol speel. Die bevindinge beklemtoon ook die potensiële invloedsmag van opinieleiers in adolessente koopgedrag en die noodsaaklikheid om hulle in reklameveldtogte te bereik
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