2017
Authors
Lopez, RG; Perraut, K; Garatti, ACO; Lazareff, B; Sanchez Bermudez, J; Benisty, M; Dougados, C; Labadie, L; Brandner, W; Garcia, PJV; Henning, T; Ray, TP; Abuter, R; Amorim, A; Anugu, N; Berger, JP; Bonnet, H; Buron, A; Caselli, P; Clenet, Y; du Foresto, VC; de Wit, W; Deen, C; Delplancke Stroebele, F; Dexter, J; Eckart, A; Eisenhauer, F; Dabo, CEG; Gendron, E; Genzel, R; Gillessen, S; Haubois, X; Haug, M; Haussmann, F; Hippler, S; Hubert, Z; Hummel, CA; Horrobin, M; Jocou, L; Kellner, S; Kervella, P; Kulas, M; Kolb, J; Lacour, S; Le Bouquin, JB; Lena, P; Lippa, M; Merand, A; Mueller, E; Ott, T; Panduro, J; Paumard, T; Perrin, G; Pfuhl, O; Ramirez, A; Rau, C; Rohloff, RR; Rousset, G; Scheithauer, S; Schoeller, M; Straubmeier, C; Sturm, E; Thi, WF; van Dishoeck, E; Vincent, F; Waisberg, I; Wank, I; Wieprecht, E; Wiest, M; Wiezorrek, E; Woillez, J; Yazici, S; Zins, G;
Publication
ASTRONOMY & ASTROPHYSICS
Abstract
Aims. To investigate the inner regions of protoplanetary discs, we performed near-infrared interferometric observations of the classical T Tauri binary system S CrA. Methods. We present the first VLTI-GRAVITY high spectral resolution (R similar to 4000) observations of a classical T Tauri binary, S CrA (composed of S CrAN and S CrA S and separated by similar to 1".4), combining the four 8m telescopes in dual-field mode. Results. Our observations in the near-infrared K-band continuum reveal a disc around each binary component, with similar halfflux radii of about 0.1 au at d similar to 130 pc, inclinations (i = 28 +/- 3 degrees and i = 22 +/- 6 degrees), and position angles (PA = 0 degrees +/- 6 degrees and PA = -2 degrees +/- 12 degrees), suggesting that they formed from the fragmentation of a common disc. The S CrAN spectrum shows bright He i and Br gamma line emission exhibiting inverse PCygni profiles, typically associated with infalling gas. The continuum-compensated Br gamma line visibilities of S CrAN show the presence of a compact Br gamma emitting region whose radius is about similar to 0.06 au, which is twice as big as the truncation radius. This component is mostly tracing a wind. Moreover, a slight radius change between the blue-and red-shifted Br gamma line components is marginally detected. Conclusions. The presence of an inverse PCygni profile in the He i and Br gamma lines, along with the tentative detection of a slightly larger size of the blue-shifted Br gamma line component, hint at the simultaneous presence of a wind and magnetospheric accretion in S CrA N.
2017
Authors
Renna, F; Oliveira, J; Coimbra, MT;
Publication
2017 COMPUTING IN CARDIOLOGY (CINC)
Abstract
In this work, we present a method to extract features from heart sound signals in order to enhance segmentation performance. The approach is data-driven, since the way features are extracted from the recorded signals is adapted to the data itself. The proposed method is based on the extraction of delay vectors, which are modeled with Gaussian mixture model priors, and an information-theoretic dimensionality reduction step which aims to maximize discrimination between delay vectors in different segments of the heart sound signal. We test our approach with heart sounds from the publicly available PhysioNet dataset showing an average F-1 score of 92.6% in detecting S-1 and S-2 sounds.
2017
Authors
Amaral, G; Silva, H; Lopes, F; Ribeiro, JP; Freitas, S; Almeida, C; Martins, A; Almeida, J; Silva, E;
Publication
OCEANS 2017 - ABERDEEN
Abstract
This paper addresses the topic of target detection and tracking using a team of UAVs for maritime border surveillance. We present a novel method on how to integrate the perception into the control loop using two distinct teams of UAVs that are cooperatively tracking the same target. We demonstrate and evaluate the effectiveness of our approach in a simulation environment.
2017
Authors
Waisberg, I; Dexter, J; Pfuhl, O; Abuter, R; Amorim, A; Anugu, N; Berger, JP; Blind, N; Bonnet, H; Brandner, W; Buron, A; Clenet, Y; de Wit, W; Deen, C; Delplancke Strobele, F; Dembet, R; Duvert, G; Eckart, A; Eisenhauer, F; Fedou, P; Finger, G; Garcia, P; Lopez, RG; Gendron, E; Genzel, R; Gillessen, S; Haubois, X; Haug, M; Haussmann, F; Henning, T; Hippler, S; Horrobin, M; Hubert, Z; Jochum, L; Jocou, L; Kervella, P; Kok, Y; Kulas, M; Lacour, S; Lapeyrere, V; Le Bouquin, JB; Lena, P; Lippa, M; Merand, A; Muller, E; Ott, T; Pallanca, L; Panduro, J; Paumard, T; Perraut, K; Perrin, G; Rabien, S; Ramirez, A; Ramos, J; Rau, C; Rohloff, RR; Rousset, G; Sanchez Bermudez, J; Scheithauer, S; Scholler, M; Straubmeier, C; Sturm, E; Vincent, F; Wank, I; Wieprecht, E; Wiest, M; Wiezorrek, E; Wittkowski, M; Woillez, J; Yazici, S;
Publication
ASTROPHYSICAL JOURNAL
Abstract
We observe the high-mass X-ray binary (HMXB) BP Cru using interferometry in the near-infrared K band with VLTI/GRAVITY. Continuum visibilities are at most partially resolved, consistent with the predicted size of the hypergiant. Differential visibility amplitude (Delta|V| similar to 5%) and phase (Delta phi similar to 2 degrees) signatures are observed across the He I 2.059 mu m and Br gamma lines, the latter seen strongly in emission, unusual for the donor star's spectral type. For a baseline B similar to 100 m, the differential phase rms similar to 0 degrees 2 corresponds to an astrometric precision of similar to 2 mu as. We generalize expressions for image centroid displacements and variances in the marginally resolved limit of interferometry to spectrally resolved data, and use them to derive model-independent properties of the emission such as its asymmetry, extension, and strong wavelength dependence. We propose geometric models based on an extended and distorted wind and/or a high-density gas stream, which has long been predicted to be present in this system. The observations show that optical interferometry is now able to resolve HMXBs at the spatial scale where accretion takes place, and therefore to probe the effects of the gravitational and radiation fields of the compact object on its environment.
2017
Authors
Pinto, AA; Zilberman, D;
Publication
Springer Proceedings in Mathematics and Statistics
Abstract
2017
Authors
Melo, VFMB; Jacobina, CB; de Freitas, NB;
Publication
IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS
Abstract
This paper proposes four open-end nine-phase conversion systems with a reduced number of controlled switches. For this to be achieved, a converter is shared among the three three-phase groups that compose the machine. In addition, in order to reduce the number of controlled switches even more, three of the studied topologies with a shared converter make use of diodes replacing some of the switches. Because of the shared converter, the configurations that make use of diodes are only applied for machines with no spatial shift between the machine three three-phase groups. Analysis of harmonic distortion for equal and unequal dc-link voltages is presented. It is shown that the harmonic distortion for configurations with diodes are higher when unequal dc-link voltages are used. Besides, study of machine torque ripple is performed and a pulse-width modulation strategy modification is made aiming torque ripple reduction for two of the proposed conversion systems. Simulation and experimental results are presented to validate the theoretical approach.
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