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Publicações

Publicações por CTM

2020

Photoplethysmography based atrial fibrillation detection: a review

Autores
Pereira, T; Tran, N; Gadhoumi, K; Pelter, MM; Do, DH; Lee, RJ; Colorado, R; Meisel, K; Hu, X;

Publicação
NPJ DIGITAL MEDICINE

Abstract
AbstractAtrial fibrillation (AF) is a cardiac rhythm disorder associated with increased morbidity and mortality. It is the leading risk factor for cardioembolic stroke and its early detection is crucial in both primary and secondary stroke prevention. Continuous monitoring of cardiac rhythm is today possible thanks to consumer-grade wearable devices, enabling transformative diagnostic and patient management tools. Such monitoring is possible using low-cost easy-to-implement optical sensors that today equip the majority of wearables. These sensors record blood volume variations—a technology known as photoplethysmography (PPG)—from which the heart rate and other physiological parameters can be extracted to inform about user activity, fitness, sleep, and health. Recently, new wearable devices were introduced as being capable of AF detection, evidenced by large prospective trials in some cases. Such devices would allow for early screening of AF and initiation of therapy to prevent stroke. This review is a summary of a body of work on AF detection using PPG. A thorough account of the signal processing, machine learning, and deep learning approaches used in these studies is presented, followed by a discussion of their limitations and challenges towards clinical applications.

2020

A Supervised Approach to Robust Photoplethysmography Quality Assessment

Autores
Pereira, T; Gadhoumi, K; Ma, MH; Liu, XY; Xiao, R; Colorado, RA; Keenan, KJ; Meisel, K; Hu, X;

Publicação
IEEE JOURNAL OF BIOMEDICAL AND HEALTH INFORMATICS

Abstract

2020

Keck all sky precision adaptive optics

Autores
Wizinowich P.; Chin J.; Correia C.; Lu J.; Brown T.; Casey K.; Cetre S.; Delorme J.R.; Gers L.; Hunter L.; Lilley S.; Ragland S.; Surendran A.; Wetherell E.; Ghez A.; Do T.; Jones T.; Liu M.; Mawet D.; Max C.; Morris M.; Treu T.; Wright S.;

Publicação
Proceedings of SPIE - The International Society for Optical Engineering

Abstract
We present the status and plans for the Keck All sky Precision Adaptive optics (KAPA) program. KAPA includes four key science programs, an upgrade to the Keck I laser guide star (LGS) adaptive optics (AO) facility to improve image quality and sky coverage, AO telemetry based point spread function (PSF) estimates for all science exposures, and an educational component focused on broadening the participation of women and underrepresented groups in instrumentation. For the purpose of this conference we will focus on the AO facility upgrade which includes implementation of a new laser, wavefront sensor and real-time controller to support laser tomography, the laser tomography system itself, and modifications to an existing near-infrared tip-tilt sensor to support multiple natural guide star (NGS) and focus measurements.

2020

The multi-object adaptive optics system for the Gemini infra-red multi-object spectrograph

Autores
Chapman S.C.; Conod U.; Turri P.; Jackson K.; Lardiere O.; Sivanandam S.; Andersen D.; Correia C.; Lamb M.; Ross C.; Sivo G.; Veran J.P.;

Publicação
Proceedings of SPIE - The International Society for Optical Engineering

Abstract
The Gemini Infra-Red Multi-Object Spectrograph (GIRMOS) is a four-arm, Multi-Object Adaptive Optics (MOAO) IFU spectrograph being built for Gemini (commissioning in 2024). GIRMOS is being planned to interface with the new Gemini-North Adaptive Optics (GNAO) system, and is base lined with a requirement of 50% EE within a 0.100 spaxel at H-band. We present a design and forecast the error budget and performance of GIRMOS-MOAO working behind GNAO. The MOAO system will patrol the 20 field of regard of GNAO, utilizing closed loop GLAO or MCAO for lower order correction. GIRMOS MOAA will perform tomographic reconstruction of the turbulence using the GNAO WFS, and utilize order 16x16 actuator DMs operating in open loop to perform an additional correction from the Pseudo Open Loop (POL) slopes, achieving close to diffraction limited performance from the combined GNAO+MOAO correction. This high performance AO spectrograph will have the broadest impact in the study of the formation and evolution of galaxies, but will also have broad reach in fields such as star and planet formation within our Milky Way and supermassive black holes in nearby galaxies.

2020

HARMONI - First light spectrograph for the ELT: Instrument final design and quantitative performance predictions

Autores
Thatte N.A.; Bryson I.; Clarke F.; Ferraro-Wood V.; Fusco T.; Le Mignant D.; Melotte D.; Neichel B.; Schnetler H.; Tecza M.; Arribas S.; Crespo A.; Piqueras A.E.; García M.G.; Santaella M.P.; Lopez J.P.; Blaizot J.; Bouché N.; Boudon D.; Chapuis D.; Daguise E.; Disseau K.; Guibert M.; Jarno A.; Jeanneau A.; Laurent F.; Loupias M.; Migniau J.E.; Piqueras L.; Remillieux A.; Richard J.; Pecontal A.; Bardou L.; Close M.; Deshmukh R.; Dimoudi S.; Dubbledam M.; King D.; Morris S.; Morris T.; O'Brien K.; Staykov L.; Swinbank M.; Townson M.; Younger E.; Accardo M.; Mendez D.A.; Conzelmann R.; Egner S.; George E.; Gonté F.; Hopgood J.; Ives D.; Mehrgan L.; Mueller E.; Peroux C.; Vernet J.; Sanchez A.A.; Battaglia G.; Cagigas M.; Delgado J.M.; Izquierdo P.F.; López A.B.F.; Garcia-Lorenzo B.; Suarez E.H.; Herreros J.M.; Joven E.; López R.; Hernando Y.M.; Mediavilla E.; Monreal A.; Castro J.P.; Rasilla J.L.; Rebolo R.; Ramos L.F.R.; Moreno A.V.; Viera T.; Carlotti A.; Correia J.J.; Delboulbe A.; Guieu S.; Hours A.; Hubert Z.; Jocou L.; Magnard Y.; Moulin T.; Pancher F.; Rabou P.; Stadler E.; Contini T.; Larrieu M.; Fantei-Caujolle Y.; Lecron D.; Rousseau S.; Beltramo-Martin O.; Bon W.; Bonnefoi A.; Ceria W.; Choquet E.; Correia C.;

Publicação
Proceedings of SPIE - The International Society for Optical Engineering

Abstract
HARMONI is the adaptive optics assisted, near-infrared and visible light integral field spectrograph for the Extremely Large Telescope (ELT). A first light instrument, it provides the work-horse spectroscopic capability for the ELT. As the project approaches its Final Design Review milestone, the design of the instrument is being finalized, and the plans for assembly, integration and testing are being detailed. We present an overview of the instrument's capabilities from a user perspective, provide a summary of the instrument's design, including plans for operations and calibrations, and provide a brief glimpse of the predicted performance for a specific observing scenario. The paper also provides some details of the consortium composition and its evolution since the project commenced in 2015.

2020

Wind-driven halo in high-contrast images: I. Analysis of the focal-plane images of SPHERE

Autores
Cantalloube, F; Farley, OJD; Milli, J; Bharmal, N; Brandner, W; Correia, C; Dohlen, K; Henning, T; Osborn, J; Por, E; Valles, MS; Vigan, A;

Publicação
ASTRONOMY & ASTROPHYSICS

Abstract
Context. The wind-driven halo is a feature that is observed in images that were delivered by the latest generation of ground-based instruments that are equipped with an extreme adaptive optics system and a coronagraphic device, such as SPHERE at the Very Large Telescope (VLT). This signature appears when the atmospheric turbulence conditions vary faster than the adaptive optics loop can correct for. The wind-driven halo is observed as a radial extension of the point spread function along a distinct direction (this is sometimes referred to as the butterfly pattern). When this is present, it significantly limits the contrast capabilities of the instrument and prevents the extraction of signals at close separation or extended signals such as circumstellar disks. This limitation is consequential because it contaminates the data for a substantial fraction of the time: about 30% of the data produced by the VLT/SPHERE instrument are affected by the wind-driven halo. Aims. This paper reviews the causes of the wind-driven halo and presents a method for analyzing its contribution directly from the scientific images. Its effect on the raw contrast and on the final contrast after post-processing is demonstrated. Methods. We used simulations and on-sky SPHERE data to verify that the parameters extracted with our method can describe the wind-driven halo in the images. We studied the temporal, spatial, and spectral variation of these parameters to point out its deleterious effect on the final contrast. Results. The data-driven analysis we propose provides information to accurately describe the wind-driven halo contribution in the images. This analysis confirms that this is a fundamental limitation of the finally reached contrast performance. Conclusions. With the established procedure, we will analyze a large sample of data delivered by SPHERE in order to propose post-processing techniques that are tailored to removing the wind-driven halo.

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