45,930 research outputs found
Gravitational waves: search results, data analysis and parameter estimation
The Amaldi 10 Parallel Session C2 on gravitational wave (GW) search results, data analysis and parameter estimation included three lively sessions of lectures by 13 presenters, and 34 posters. The talks and posters covered a huge range of material, including results and analysis techniques for ground-based GW detectors, targeting anticipated signals from different astrophysical sources: compact binary inspiral, merger and ringdown; GW bursts from intermediate mass binary black hole mergers, cosmic string cusps, core-collapse supernovae, and other unmodeled sources; continuous waves from spinning neutron stars; and a stochastic GW background. There was considerable emphasis on Bayesian techniques for estimating the parameters of coalescing compact binary systems from the gravitational waveforms extracted from the data from the advanced detector network. This included methods to distinguish deviations of the signals from what is expected in the context of General Relativity
A Hierarchical Recurrent Encoder-Decoder For Generative Context-Aware Query Suggestion
Users may strive to formulate an adequate textual query for their information
need. Search engines assist the users by presenting query suggestions. To
preserve the original search intent, suggestions should be context-aware and
account for the previous queries issued by the user. Achieving context
awareness is challenging due to data sparsity. We present a probabilistic
suggestion model that is able to account for sequences of previous queries of
arbitrary lengths. Our novel hierarchical recurrent encoder-decoder
architecture allows the model to be sensitive to the order of queries in the
context while avoiding data sparsity. Additionally, our model can suggest for
rare, or long-tail, queries. The produced suggestions are synthetic and are
sampled one word at a time, using computationally cheap decoding techniques.
This is in contrast to current synthetic suggestion models relying upon machine
learning pipelines and hand-engineered feature sets. Results show that it
outperforms existing context-aware approaches in a next query prediction
setting. In addition to query suggestion, our model is general enough to be
used in a variety of other applications.Comment: To appear in Conference of Information Knowledge and Management
(CIKM) 201
Solar Flare Measurements with STIX and MiSolFA
Solar flares are the most powerful events in the solar system and the
brightest sources of X-rays, often associated with emission of particles
reaching the Earth and causing geomagnetic storms, giving problems to
communication, airplanes and even black-outs. X-rays emitted by accelerated
electrons are the most direct probe of solar flare phenomena. The Micro
Solar-Flare Apparatus (MiSolFA) is a proposed compact X-ray detector which will
address the two biggest issues in solar flare modeling. Dynamic range
limitations prevent simultaneous spectroscopy with a single instrument of all
X-ray emitting regions of a flare. In addition, most X-ray observations so far
are inconsistent with the high anisotropy predicted by the models usually
adopted for solar flares. Operated at the same time as the STIX instrument of
the ESA Solar Orbiter mission, at the next solar maximum (2020), they will have
the unique opportunity to look at the same flare from two different directions:
Solar Orbiter gets very close to the Sun with significant orbital inclination;
MiSolFA is in a near-Earth orbit. To solve the cross-calibration problems
affecting all previous attempts to combine data from different satellites,
MiSolFA will adopt the same photon detectors as STIX, precisely quantifying the
anisotropy of the X-ray emission for the first time. By selecting flares whose
footpoints (the brightest X-ray sources, at the chromosphere) are occulted by
the solar limb for one of the two detectors, the other will be able to study
the much fainter coronal emission, obtaining for the first time simultaneous
observations of all interesting regions. MiSolFA shall operate on board of a
very small satellite, with several launch opportunities, and will rely on
moir\'e imaging techniques.Comment: Invited talk, N30-8, Astrophysics and Space Instrumentation session,
2014 Nuclear Science Symposium and Medical Imaging Conference, 11 Nov 201
Constraining strangeness in dense matter with GW170817
Particles with strangeness content are predicted to populate dense matter,
modifying the equation of state of matter inside neutron stars as well as their
structure and evolution. In this work, we show how the modeling of strangeness
content in dense matter affects the properties of isolated neutrons stars and
the tidal deformation in binary systems. For describing nucleonic and hyperonic
stars we use the many-body forces model (MBF) at zero temperature, including
the mesons for the description of repulsive hyperon-hyperon
interactions. Hybrid stars are modeled using the MIT Bag Model with vector
interaction (vMIT) in both Gibbs and Maxwell constructions, for different
values of bag constant and vector interaction couplings. A parametrization with
a Maxwell construction, which gives rise to third family of compact stars (twin
stars), is also investigated. We calculate the tidal contribution that adds to
the post-Newtonian point-particle corrections, the associated love number for
sequences of stars of different composition (nucleonic, hyperonic, hybrid and
twin stars), and determine signatures of the phase transition on the
gravitational waves in the accumulated phase correction during the inspirals
among different scenarios for binary systems. On the light of the recent
results from GW170817 and the implications for the radius of
stars, our results show that hybrid stars can
only exist if a phase transition takes place at low densities close to
saturation
Determining DfT Hardware by VHDL-AMS Fault Simulation for Biological Micro-Electronic Fluidic Arrays
The interest of microelectronic fluidic arrays for biomedical applications, like DNA determination, is rapidly increasing. In order to evaluate these systems in terms of required Design-for-Test structures, fault simulations in both fluidic and electronic domains are necessary. VHDL-AMS can be used successfully in this case. This paper shows a highly testable architecture of a DNA Bio-Sensing array, its basic sensing concept, fluidic modeling and sensitivity analysis. The overall VHDL-AMS fault simulation of the system is shown
Extreme Starbursts in the Local Universe
The "Extreme starbursts in the local universe" workshop was held at the
Insituto de Astrofisica de Andalucia in Granada, Spain on 21-25 June 2010.
Bearing in mind the advent of a new generation of facilities such as JWST,
Herschel, ALMA, eVLA and eMerlin, the aim of the workshop was to bring together
observers and theorists to review the latest results. The purpose of the
workshop was to address the following issues: what are the main modes of
triggering extreme starbursts in the local Universe? How efficiently are stars
formed in extreme starbursts? What are the star formation histories of local
starburst galaxies? How well do the theoretical simulations model the
observations? What can we learn about starbursts in the distant Universe
through studies of their local counterparts? How important is the role of
extreme starbursts in the hierarchical assembly of galaxies? How are extreme
starbursts related to the triggering of AGN in the nuclei of galaxies? Overall,
41 talks and 4 posters with their corresponding 10 minutes short talks were
presented during the workshop. In addition, the workshop was designed with
emphasis on discussions, and therefore, there were 6 discussion sessions of up
to one hour during the workshop. Here is presented a summary of the purposes of
the workshop as well as a compilation of the abstracts corresponding to each of
the presentations. The summary and conclusions of the workshop along with a
description of the future prospects by Sylvain Veilleux can be found in the
last section of this document. A photo of the assistants is included.Comment: worksho
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