5,494 research outputs found
StreamLearner: Distributed Incremental Machine Learning on Event Streams: Grand Challenge
Today, massive amounts of streaming data from smart devices need to be
analyzed automatically to realize the Internet of Things. The Complex Event
Processing (CEP) paradigm promises low-latency pattern detection on event
streams. However, CEP systems need to be extended with Machine Learning (ML)
capabilities such as online training and inference in order to be able to
detect fuzzy patterns (e.g., outliers) and to improve pattern recognition
accuracy during runtime using incremental model training. In this paper, we
propose a distributed CEP system denoted as StreamLearner for ML-enabled
complex event detection. The proposed programming model and data-parallel
system architecture enable a wide range of real-world applications and allow
for dynamically scaling up and out system resources for low-latency,
high-throughput event processing. We show that the DEBS Grand Challenge 2017
case study (i.e., anomaly detection in smart factories) integrates seamlessly
into the StreamLearner API. Our experiments verify scalability and high event
throughput of StreamLearner.Comment: Christian Mayer, Ruben Mayer, and Majd Abdo. 2017. StreamLearner:
Distributed Incremental Machine Learning on Event Streams: Grand Challenge.
In Proceedings of the 11th ACM International Conference on Distributed and
Event-based Systems (DEBS '17), 298-30
Eclipsing Binary Stars from Space
We have begun a programme to obtain high-precision photometry of bright
detached eclipsing binary (dEB) stars with the Wide field InfraRed Explorer
(WIRE) satellite. Due to the small aperture of WIRE only stars brighter than
V=6 can be observed. We are collecting data for about a dozen dEB targets and
here we present preliminary results for three of them. We have chosen dEBs with
primary components of B and early A type. One of our aims is to combine the
information from the light curve analyses of the eclipses with asteroseismic
information from the analysis of the pulsation of the primary component.Comment: 4 pages, 3 figures. To appear in conference proceedings for IAU
Symposium No. 240: Binary Stars as Critical Tools & Tests in Contemporary
Astrophysics, eds. W. Hartkopf, E. Guinan & P. Harmane
The Interior Structure Constants as an Age Diagnostic for Low-Mass, Pre-Main Sequence Detached Eclipsing Binary Stars
We propose a novel method for determining the ages of low-mass, pre-main
sequence stellar systems using the apsidal motion of low-mass detached
eclipsing binaries. The apsidal motion of a binary system with an eccentric
orbit provides information regarding the interior structure constants of the
individual stars. These constants are related to the normalized stellar
interior density distribution and can be extracted from the predictions of
stellar evolution models. We demonstrate that low-mass, pre-main sequence stars
undergoing radiative core contraction display rapidly changing interior
structure constants (greater than 5% per 10 Myr) that, when combined with
observational determinations of the interior structure constants (with 5 -- 10%
precision), allow for a robust age estimate. This age estimate, unlike those
based on surface quantities, is largely insensitive to the surface layer where
effects of magnetic activity are likely to be most pronounced. On the main
sequence, where age sensitivity is minimal, the interior structure constants
provide a valuable test of the physics used in stellar structure models of
low-mass stars. There are currently no known systems where this technique is
applicable. Nevertheless, the emphasis on time domain astronomy with current
missions, such as Kepler, and future missions, such as LSST, has the potential
to discover systems where the proposed method will be observationally feasible.Comment: Accepted for publication in ApJ, 8 pages, 3 figure
Eclipsing Binary Stars: the Royal Road to Stellar Astrophysics
Russell (1948) famously described eclipses as the "royal road" to stellar
astrophysics. From photometric and spectroscopic observations it is possible to
measure the masses and radii (to 1% or better!), and thus surface gravities and
mean densities, of stars in eclipsing binary systems using nothing more than
geometry. Adding an effective temperature subsequently yields luminosity and
then distance (or vice versa) to high precision. This wealth of directly
measurable quantities makes eclipsing binaries the primary source of empirical
information on the properties of stars, and therefore a cornerstone of stellar
astrophysics. In this review paper I summarise the current standing of
eclipsing binary research, present an overview of useful analysis techniques,
and conclude with a glance to the future.Comment: 8 pages, 3 figures. Invited review for the Pas De Deux conference,
Paris, October 201
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