991 research outputs found
Brain-computer interface technology for speech recognition: A review
This paper presents an overview of the studies that have been conducted with the purpose of understanding the use of brain signals as input to a speech recogniser. The studies have been categorised based on the type of the technology used with a summary of the methodologies used and achieved results. In addition, the paper gives an insight into some studies that examined the effect of the chosen stimuli on brain activities as an important factor in the recognition process. The remaining part of this paper lists the limitations of the available studies and the challenges for future work in this area
Propagators and WKB-exactness in the plane wave limit of AdSxS
Green functions for the scalar, spinor and vector fields in a plane wave
geometry arising as a Penrose limit of are obtained. The
Schwinger-DeWitt technique directly gives the results in the plane wave
background, which turns out to be WKB-exact. Therefore the structural
similarity with flat space results is unveiled. In addition, based on the local
character of the Penrose limit, it is claimed that for getting the correct
propagators in the limit one can rely on the first terms of the direct geodesic
contribution in the Schwinger-DeWitt expansion of the original propagators .
This is explicitly shown for the Einstein Static Universe, which has the same
Penrose limit as with equal radii, and for a number of other
illustrative cases.Comment: 18 pages, late
Tunable variation of optical properties of polymer capped gold nanoparticles
Optical properties of polymer capped gold nanoparticles of various sizes
(diameter 3-6 nm) have been studied. We present a new scheme to extract size
dependent variation of total dielectric function of gold nanoparticles from
measured UV-Vis absorption data. The new scheme can also be used, in principle,
for other related systems as well. We show how quantum effect, surface atomic
co - ordination and polymer - nanoparticle interface morphology leads to a
systematic variation in inter band part of the dielectric function of gold
nanoparticles, obtained from the analysis using our new scheme. Careful
analysis enables identification of the possible changes to the electronic band
structure in such nanoparticles.Comment: 13 pages,7 figures, 1 tabl
Quantum Interference: From Kaons to Neutrinos (with Quantum Beats in between)
Using the vehicle of resolving an apparent paradox, a discussion of quantum
interference is presented. The understanding of a number of different physical
phenomena can be unified, in this context. These range from the neutral kaon
system to massive neutrinos, not to mention quantum beats, Rydberg wave
packets, and neutron gravity.Comment: 12 pages, LaTeX, 3 figure
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The energy spectrometer for particles (ESP): Instrument description and orbital performance
The ESP detector is functionally described, along with the pertinent orbital and spin properties of the spacecraft that supports it. The phoswiched plastic/BGO scintillators sensor design, electronic implementation, and resulting data types are recounted, and the ground calibration procedures are reported. Several illustrative examples of data are given, including the solar proton event of 29 September 1989, and the nearly periodic episodes of high relativistic electron flux that are associated with solar coronal holes which have been a dominant feature of the space weather over the past few years. 2 refs., 10 figs., 1 tab
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