80,071 research outputs found
Smart enterprise for pulp & paper mills: Data processing and reconciliation
An ad-hoc data reconciliation procedure developed for the recausticizing section of a new pulp and paper industry is presented in this work. A comprehensive model was formulated to take into account different unit operation modes. It was also extended to incorporate specific knowledge of some pieces of equipment to increase redundancy, and consequently enhance estimate precision and gross error detectability. © 2002 Elsevier B.V. All rights reserved.Fil: Sanchez, Mabel Cristina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Planta Piloto de IngenierĂa QuĂmica. Universidad Nacional del Sur. Planta Piloto de IngenierĂa QuĂmica; ArgentinaFil: Leung David. Visy Pulp And Paper Pty Ltd; AustraliaFil: Konecsny Helmut. Visy Pulp And Paper Pty Ltd; AustraliaFil: Bigaran Carlo. Visy Pulp And Paper Pty Ltd; AustraliaFil: Romagnoli JosĂ©. University Of Sydney; Australi
Sparse Representation of Astronomical Images
Sparse representation of astronomical images is discussed. It is shown that a
significant gain in sparsity is achieved when particular mixed dictionaries are
used for approximating these types of images with greedy selection strategies.
Experiments are conducted to confirm: i)Effectiveness at producing sparse
representations. ii)Competitiveness, with respect to the time required to
process large images.The latter is a consequence of the suitability of the
proposed dictionaries for approximating images in partitions of small
blocks.This feature makes it possible to apply the effective greedy selection
technique Orthogonal Matching Pursuit, up to some block size. For blocks
exceeding that size a refinement of the original Matching Pursuit approach is
considered. The resulting method is termed Self Projected Matching Pursuit,
because is shown to be effective for implementing, via Matching Pursuit itself,
the optional back-projection intermediate steps in that approach.Comment: Software to implement the approach is available on
http://www.nonlinear-approx.info/examples/node1.htm
Pupil remapping for high contrast astronomy: results from an optical testbed
The direct imaging and characterization of Earth-like planets is among the
most sought-after prizes in contemporary astrophysics, however current optical
instrumentation delivers insufficient dynamic range to overcome the vast
contrast differential between the planet and its host star. New opportunities
are offered by coherent single mode fibers, whose technological development has
been motivated by the needs of the telecom industry in the near infrared. This
paper presents a new vision for an instrument using coherent waveguides to
remap the pupil geometry of the telescope. It would (i) inject the full pupil
of the telescope into an array of single mode fibers, (ii) rearrange the pupil
so fringes can be accurately measured, and (iii) permit image reconstruction so
that atmospheric blurring can be totally removed. Here we present a laboratory
experiment whose goal was to validate the theoretical concepts underpinning our
proposed method. We successfully confirmed that we can retrieve the image of a
simulated astrophysical object (in this case a binary star) though a pupil
remapping instrument using single mode fibers.Comment: Accepted in Optics Expres
MYSTIC: Michigan Young STar Imager at CHARA
We present the design for MYSTIC, the Michigan Young STar Imager at CHARA.
MYSTIC will be a K-band, cryogenic, 6-beam combiner for the Georgia State
University CHARA telescope array. The design follows the image-plane
combination scheme of the MIRC instrument where single-mode fibers bring
starlight into a non-redundant fringe pattern to feed a spectrograph. Beams
will be injected in polarization-maintaining fibers outside the cryogenic dewar
and then be transported through a vacuum feedthrough into the ~220K cold volume
where combination is achieved and the light is dispersed. We will use a C-RED
One camera (First Light Imaging) based on the eAPD SAPHIRA detector to allow
for near-photon-counting performance. We also intend to support a 4-telescope
mode using a leftover integrated optics component designed for the VLTI-GRAVITY
experiment, allowing better sensitivity for the faintest targets. Our primary
science driver motivation is to image disks around young stars in order to
better understand planet formation and how forming planets might influence disk
structures.Comment: Presented at the 2018 SPIE Astronomical Telescopes + Instrumentation,
Austin, Texas, US
Dimensionality Reduction and Classification feature using Mutual Information applied to Hyperspectral Images : A Filter strategy based algorithm
Hyperspectral images (HIS) classification is a high technical remote sensing
tool. The goal is to reproduce a thematic map that will be compared with a
reference ground truth map (GT), constructed by expecting the region. The HIS
contains more than a hundred bidirectional measures, called bands (or simply
images), of the same region. They are taken at juxtaposed frequencies.
Unfortunately, some bands contain redundant information, others are affected by
the noise, and the high dimensionality of features made the accuracy of
classification lower. The problematic is how to find the good bands to classify
the pixels of regions. Some methods use Mutual Information (MI) and threshold,
to select relevant bands, without treatment of redundancy. Others control and
eliminate redundancy by selecting the band top ranking the MI, and if its
neighbors have sensibly the same MI with the GT, they will be considered
redundant and so discarded. This is the most inconvenient of this method,
because this avoids the advantage of hyperspectral images: some precious
information can be discarded. In this paper we'll accept the useful redundancy.
A band contains useful redundancy if it contributes to produce an estimated
reference map that has higher MI with the GT.nTo control redundancy, we
introduce a complementary threshold added to last value of MI. This process is
a Filter strategy; it gets a better performance of classification accuracy and
not expensive, but less preferment than Wrapper strategy.Comment: 11 pages, 5 figures, journal pape
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