3,732 research outputs found
Using Scalp Electrical Biosignals to Control an Object by Concentration and Relaxation Tasks: Design and Evaluation
In this paper we explore the use of electrical biosignals measured on scalp
and corresponding to mental relaxation and concentration tasks in order to
control an object in a video game. To evaluate the requirements of such a
system in terms of sensors and signal processing we compare two designs. The
first one uses only one scalp electroencephalographic (EEG) electrode and the
power in the alpha frequency band. The second one uses sixteen scalp EEG
electrodes and machine learning methods. The role of muscular activity is also
evaluated using five electrodes positioned on the face and the neck. Results
show that the first design enabled 70% of the participants to successfully
control the game, whereas 100% of the participants managed to do it with the
second design based on machine learning. Subjective questionnaires confirm
these results: users globally felt to have control in both designs, with an
increased feeling of control in the second one. Offline analysis of face and
neck muscle activity shows that this activity could also be used to distinguish
between relaxation and concentration tasks. Results suggest that the
combination of muscular and brain activity could improve performance of this
kind of system. They also suggest that muscular activity has probably been
recorded by EEG electrodes.Comment: International Conference of the IEEE EMBS (2011
The conversion of Neutron star to Strange star : A two step process
The conversion of neutron matter to strange matter in a neutron star have
been studied as a two step process. In the first step, the nuclear matter gets
converted to two flavour quark matter. The conversion of two flavour to three
flavour strange matter takes place in the second step. The first process is
analysed with the help of equations of state and hydrodynamical equations,
whereas, in the second process, non-leptonic weak interaction plays the main
role. Velocities and the time of travel through the star of these two
conversion fronts have been analysed and compared.Comment: 18 pages including 9 figure
Sensitivity to alpha-variation in ultracold atomic-scattering experiments
We present numerical calculations for cesium and mercury to estimate the
sensitivity of the scattering length to the variation of the fine structure
constant alpha. The method used follows ideas Chin and Flambaum [Phys. Rev.
Lett. 96, 230801 (2006)], where the sensitivity to the variation of the
electron to proton mass ratio, beta, was considered. We demonstrate that for
heavy systems, the sensitivity to variation of alpha is of the same order of
magnitude as to variation of beta. Near narrow Feshbach resonances the
enhancement of the sensitivity may exceed nine orders of magnitude.Comment: 5 pages, 1 figur
A Model for Configuration Management of Open Software Systems
The article proposes a model for the configuration management of open
systems. The model aims at validation of configurations against given
specifications. An extension of decision graphs is proposed to express
specifications. The proposed model can be used by software developers to
validate their own configurations across different versions of the components,
or to validate configurations that include components by third parties. The
model can also be used by end-users to validate compatibility among different
configurations of the same application. The proposed model is first discussed
in some application scenarios and then formally defined. Moreover, a type
discipline is given to formally define validation of a configuration against a
system specificationComment: 13 page
Near IR luminescent rare earth 3,4,5,6-tetrafluoro-2-nitrophenoxide complexes: Synthesis, X-ray crystallography and spectroscopy
NOTICE: this is the author’s version of a work that was accepted for publication in Near IR luminescent rare earth 3,4,5,6-tetrafluoro-2-nitrophenoxide complexes: Synthesis, X-ray crystallography and spectroscopy. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Near IR luminescent rare earth 3,4,5,6-tetrafluoro-2-nitrophenoxide complexes: Synthesis, X-ray crystallography and spectroscopy, [VOL27, ISSUE5, (2008)] DOI: 10.1016/j.poly.2008.01.02
Possibility to realize spin-orbit-induced correlated physics in iridium fluorides
Recent theoretical predictions of "unprecedented proximity" of the electronic
ground state of iridium fluorides to the SU(2) symmetric
limit, relevant for superconductivity in iridates, motivated us to investigate
their crystal and electronic structure. To this aim, we performed
high-resolution x-ray powder diffraction, Ir L-edge resonant inelastic
x-ray scattering, and quantum chemical calculations on Rb[IrF] and
other iridium fluorides. Our results are consistent with the Mott insulating
scenario predicted by Birol and Haule [Phys. Rev. Lett. 114, 096403 (2015)],
but we observe a sizable deviation of the state from the
SU(2) symmetric limit. Interactions beyond the first coordination shell of
iridium are negligible, hence the iridium fluorides do not show any magnetic
ordering down to at least 20 K. A larger spin-orbit coupling in iridium
fluorides compared to oxides is ascribed to a reduction of the degree of
covalency, with consequences on the possibility to realize spin-orbit-induced
strongly correlated physics in iridium fluorides
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