Articles
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10/02/2021--
01/25/2021
Design and Fabrication of Metamaterial Anti-Reflection Coatings for the Simons Observatory
The Simons Observatory (SO) will be a cosmic microwave background (CMB)
survey experiment with three small-aperture telescopes and one large-aperture
telescope, which will observe from the Atacama Desert in Chile. In total, SO
will field over 60,000 transition-edge sensor (TES) bolometers in six spectral
bands centered between 27 and 280 GHz in order to achieve the sensitivity
necessary to measure or constrain numerous cosmological quantities, as outlined
in The Simons Observatory Collaboration et al. (2019). These telescopes require
33 highly transparent, large aperture, refracting optics. To this end, we
developed mechanically robust, highly efficient, metamaterial anti-reflection
(AR) coatings with octave bandwidth coverage for silicon optics up to 46 cm in
diameter for the 22-55, 75-165, and 190-310 GHz bands. We detail the design,
the manufacturing approach to fabricate the SO lenses, their performance, and
possible extensions of metamaterial AR coatings to optical elements made of
harder materials such as alumina.
Joseph E. Golec
Jeffrey J. McMahon
Aamir M. Ali
Grace E. Chesmore
Leah Cooperrider
Simon Dicker
Nicholas Galitzki
Kathleen Harrington
Rebecca Jackson
Benjamin Westbrook
Edward J. Wollack
Zhilei Xu
Ningfeng Zhu
12/09/1998--
12/09/1998
Revisting Lepton Pairs at the SPS
We confirm the importance of standard medium effects (hadronic rescattering)
in heavy-ion collisions by using a pQCD-based model to investigate the dilepton
spectra from Pb+Au collisions at 158 GeV/nucleon.
J. Murray
W. Bauer
K. Haglin
06/29/2010--
06/29/2010
Working Document on Gloss Ontology
This document describes the Gloss Ontology. The ontology and associated class
model are organised into several packages. Section 2 describes each package in
detail, while Section 3 contains a summary of the whole ontology.
Joelle Coutaz
Alan Dearle
Sophie Dupuy-Chessa
Graham Kirby
Christophe Lachenal
Ron Morrison
Gaetan Rey
Evangelos Zirintsis
10/16/2004--
10/16/2004
Modeling of a chlorine high-density plasma submitted to a static magnetic field
This paper extends the results of a recently developed one-dimensional model
aiming to describe the characteristics of a magnetized chlorine high-density
plasma. In this work, the dependence of the plasma characteristics on the
magnetic field intensity is investigated. It is shown that the dissociation
degree and the relative weight of the various charged species is strongly
influenced by the magnetic field when the gas pressure is low enough. In
contrast, at higher pressure, the plasma is essentially composed of negative
ions, and molecular neutrals and ions, independently of the field intensity. It
is further demonstrated that diffusion needs to be considered in order to
correctly predict the plasma behavior.
Jean-Sebastien Poirier
Luc Stafford
Joelle Margot
Francois Vidal
Karl Giroux
Antoine Quintal-Leonard
Mohamed Chaker
10/18/2004--
10/18/2004
Influence of dissociative recombination on the LTE of argon high-frequency plasmas at atmospheric pressure
This work presents a few preliminary results from a collisional-radiative
(CR) model intended to describe an argon microwave (2.45 GHz) plasma at
atmospheric pressure. This model aims to investigate the influence of
dissociative recombination products on the Saha-Boltzmann plasma equilibrium.
The model is tested through comparison with experimental results obtained in an
argon plasma column generated by a traveling electromagnetic surface-wave,
which is suitable to perform a parametric investigation of the plasma. It is
shown that dissociative recombination predominantly populates the 4s levels and
the ground state. It is further observed that it strongly influences the
population of the levels, specially those of lower energy. However, the higher
levels (close to the ionization limit) appear to be in equilibrium whatever the
plasma density. This allows assuming that the excitation temperature Texc
determined from the upper levels in the atomic system in the Boltzmann-plot is
equal to Te.
Abel Sainz
Joelle Margot
Maria Carmen Garcia
Maria Dolores Calzada
04/22/2014--
04/22/2014
A Logical Framework for Systems Biology
We propose a novel approach for the formal verification of biological systems
based on the use of a modal linear logic. We show how such a logic can be used,
with worlds as instants of time, as an unified framework to encode both
biological systems and temporal properties of their dynamic behaviour. To
illustrate our methodology, we consider a model of the P53/Mdm2 DNA-damage
repair mechanism. We prove several properties that are important for such a
model to satisfy and serve to illustrate the promise of our approach. We
formalize the proofs of these properties in the Coq Proof Assistant, with the
help of a Lambda Prolog prover for partial automation of the proofs.
Elisabetta De Maria
Joelle Despeyroux
Amy Felty
01/18/2017--
01/18/2017
(Mathematical) Logic for Systems Biology (Invited Paper)
We advocates here the use of (mathematical) logic for systems biology, as a
unified framework well suited for both modeling the dynamic behaviour of
biological systems, expressing properties of them, and verifying these
properties. The potential candidate logics should have a traditional proof
theoretic pedigree (including a sequent calculus presentation enjoying
cut-elimination and focusing), and should come with (certified) proof tools.
Beyond providing a reliable framework, this allows the adequate encodings of
our biological systems. We present two candidate logics (two modal extensions
of linear logic, called HyLL and SELL), along with biological examples. The
examples we have considered so far are very simple ones-coming with completely
formal (interactive) proofs in Coq. Future works includes using automatic
provers, which would extend existing automatic provers for linear logic. This
should enable us to specify and study more realistic examples in systems
biology, biomedicine (diagnosis and prognosis), and eventually neuroscience.
Joëlle Despeyroux
02/07/2015--
02/07/2015
Coupled effects of applied load and surface structure on the viscous forces during peeling
Tree frogs are able take advantage of an interconnected network of epithelial
cells in their toe pads to modulate their adhesion to surfaces under dry, wet,
and flooded environments. It has been hypothesized that these interconnected
drainage channels reduce the hydrodynamic repulsion to facilitate contact under
a completely submerged environment (flooded conditions). Using a custom-built
apparatus we investigate the interplay between surface structure and loading
conditions on the peeling force. By combining a normal approach and detachment
by peeling we can isolate the effects of surface structure from the loading
conditions. We investigate three surfaces: two rigid structured surfaces that
consist of arrays of cylindrical posts and a flat surface as a control. We
observe three regimes in the work required to separate the structured surface
that depend on the fluid film thickness prior to pull out. These three regimes
are based on hydrodynamics and our experimental results agree with a simple
scaling argument that relates the surface features to the different regimes
observed. Overall we find that the work of separation of a structured surface
is always less than or equal to the one for a smooth surface when considering
purely viscous contributions.
Charles Dhong
Joelle Frechette
08/01/2023--
08/01/2023
Exploiting the dynamics of commodity futures curves
The Nelson-Siegel framework is employed to model the term structure of
commodity futures prices. Exploiting the information embedded in the level,
slope and curvature parameters, we develop novel investment strategies that
assume short-term continuation of recent parallel, slope or butterfly movements
of futures curves. Systematic strategies based on the change in the slope
generate significant profits that are unrelated to previously documented risk
factors and can survive reasonable transaction costs. Further analysis
demonstrates that the profitability of the slope strategy increases with
investor sentiment and is in part a compensation for the drawdowns incurred
during economic slowdowns. The profitability can also be magnified through
timing and persists under alternative specifications of the Nelson-Siegel
model.
Robert J Bianchi
John Hua Fan
Joelle Miffre
Tingxi Zhang
04/15/2025--
04/15/2025
SAR-to-RGB Translation with Latent Diffusion for Earth Observation
Earth observation satellites like Sentinel-1 (S1) and Sentinel-2 (S2) provide
complementary remote sensing (RS) data, but S2 images are often unavailable due
to cloud cover or data gaps. To address this, we propose a diffusion model
(DM)-based approach for SAR-to-RGB translation, generating synthetic optical
images from SAR inputs. We explore three different setups: two using Standard
Diffusion, which reconstruct S2 images by adding and removing noise (one
without and one with class conditioning), and one using Cold Diffusion, which
blends S2 with S1 before removing the SAR signal. We evaluate the generated
images in downstream tasks, including land cover classification and cloud
removal. While generated images may not perfectly replicate real S2 data, they
still provide valuable information. Our results show that class conditioning
improves classification accuracy, while cloud removal performance remains
competitive despite our approach not being optimized for it. Interestingly,
despite exhibiting lower perceptual quality, the Cold Diffusion setup performs
well in land cover classification, suggesting that traditional quantitative
evaluation metrics may not fully reflect the practical utility of generated
images. Our findings highlight the potential of DMs for SAR-to-RGB translation
in RS applications where RGB images are missing.
Kaan Aydin
Joelle Hanna
Damian Borth
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