7,094 research outputs found
GRB/GW association: Long-short GRB candidates, time-lag, measuring gravitational wave velocity and testing Einstein's equivalence principle
Short-duration gamma-ray bursts (SGRBs) are widely believed to be powered by
the mergers of compact binaries, such as binary neutron stars or possibly
neutron star-black hole binaries. Though the prospect of detecting SGRBs with
gravitational wave (GW) signals by the advanced Laser Interferometer
Gravitational-Wave Observatory (LIGO)/VIRGO network is promising, no known SGRB
has been found within the expected advanced LIGO/VIRGO sensitivity range for
binary neutron star systems. We find, however, that the two long-short GRBs
(GRB 060505 and GRB 060614) may be within the horizon of advanced GW detectors.
In the upcoming era of GW astronomy, the merger origin of some long-short GRBs,
as favored by the macronova signature displayed in GRB 060614, can be
unambiguously tested. The model-dependent time lags between the merger and the
onset of the prompt emission of the GRB are estimated. The comparison of such
time lags between model predictions and the real data expected in the era of
the GW astronomy would be helpful in revealing the physical processes taking
place at the central engine (including the launch of the relativistic outflow,
the emergence of the outflow from the dense material ejected during the merger,
and the radiation of gamma rays). We also show that the speed of GWs, with or
without a simultaneous test of Einstein's equivalence principle, can be
directly measured to an accuracy of or
even better in the advanced LIGO/VIRGO era. The Astrophysical Journal, VolumeComment: 12 pages, 3 figures, published in The Astrophysical Journa
Sketch-based Video Object Segmentation: Benchmark and Analysis
Reference-based video object segmentation is an emerging topic which aims to
segment the corresponding target object in each video frame referred by a given
reference, such as a language expression or a photo mask. However, language
expressions can sometimes be vague in conveying an intended concept and
ambiguous when similar objects in one frame are hard to distinguish by
language. Meanwhile, photo masks are costly to annotate and less practical to
provide in a real application. This paper introduces a new task of sketch-based
video object segmentation, an associated benchmark, and a strong baseline. Our
benchmark includes three datasets, Sketch-DAVIS16, Sketch-DAVIS17 and
Sketch-YouTube-VOS, which exploit human-drawn sketches as an informative yet
low-cost reference for video object segmentation. We take advantage of STCN, a
popular baseline of semi-supervised VOS task, and evaluate what the most
effective design for incorporating a sketch reference is. Experimental results
show sketch is more effective yet annotation-efficient than other references,
such as photo masks, language and scribble.Comment: BMVC 202
The Electromechanical Behavior of a Micro-Ring Driven by Traveling Electrostatic Force
There is no literature mentioning the electromechanical behavior of micro structures driven by traveling electrostatic forces. This article is thus the first to present the dynamics and stabilities of a micro-ring subjected to a traveling electrostatic force. The traveling electrostatic force may be induced by sequentially actuated electrodes which are arranged around the flexible micro-ring. The analysis is based on a linearized distributed model considering the electromechanical coupling effects between electrostatic force and structure. The micro-ring will resonate when the traveling speeds of the electrostatic force approach some critical speeds. The critical speeds are equal to the ratio of the natural frequencies to the wave number of the correlative natural mode of the ring. Apart from resonance, the ring may be unstable at some unstable traveling speeds. The unstable regions appear not only near the critical speeds, but also near some fractions of some critical speeds differences. Furthermore the unstable regions expand with increasing driving voltage. This article may lead to a new research branch on electrostatic-driven micro devices
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