431 research outputs found
Computational Analyses of Arabic Morphology
This paper demonstrates how a (multi-tape) two-level formalism can be used to
write two-level grammars for Arabic non-linear morphology using a high level,
but computationally tractable, notation. Three illustrative grammars are
provided based on CV-, moraic- and affixational analyses. These are
complemented by a proposal for handling the hitherto computationally untreated
problem of the broken plural. It will be shown that the best grammars for
describing Arabic non-linear morphology are moraic in the case of templatic
stems, and affixational in the case of a-templatic stems. The paper will
demonstrate how the broken plural can be derived under two-level theory via the
`implicit' derivation of the singular.Comment: to appear in Narayanan A., Ditters E. (eds). The Linguistic
Computation of Arabic. uuencoded, compressed .ps file, 27 page
Lasing from single, stationary, dye-doped glycerol/water microdroplets located on a superhydrophobic surface
We report laser emission from single, stationary, Rhodamine B-doped
glycerol/water microdroplets located on a superhydrophobic surface. In the
experiments, a pulsed, frequency-doubled Nd:YAG laser operating at 532 nm was
used as the excitation source. The microdroplets ranged in diameter from a few
to 20 um. Lasing was achieved in the red-shifted portion of the dye emission
spectrum with threshold fluences as low as 750 J/cm2. Photobleaching was
observed when the microdroplets were pumped above threshold. In certain cases,
multimode lasing was also observed and attributed to the simultaneous lasing of
two modes belonging to different sets of whispering gallery modes.Comment: to appear in Optics Communication
A method for volume stabilization of single, dye-doped water microdroplets with femtoliter resolution
A self-control mechanism that stabilizes the size of Rhodamine B-doped water
microdroplets standing on a superhydrophobic surface is demonstrated. The
mechanism relies on the interplay between the condensation rate that was kept
constant and evaporation rate induced by laser excitation which critically
depends on the size of the microdroplets. The radii of individual water
microdroplets (>5 um) stayed within a few nanometers during long time periods
(up to 455 seconds). By blocking the laser excitation for 500 msec, the stable
volume of individual microdroplets was shown to change stepwise.Comment: to appear in the J. Op. Soc. Am.
Dye lasing in optically manipulated liquid aerosols
We report lasing in airborne, rhodamine B-doped glycerol-water droplets with diameters ranging between 7.7 and 11.0 mu m, which were localized using optical tweezers. While being trapped near the focal point of an infrared laser, the droplets were pumped with a Q-switched green laser. Our experiments revealed nonlinear dependence of the intensity of the droplet whispering gallery modes (WGMs) on the pump laser fluence, indicating dye lasing. The average wavelength of the lasing WGMs could be tuned between 600 and 630 nm by changing the droplet size. These results may lead to new ways of probing airborne particles, exploiting the high sensitivity of stimulated emission to small perturbations in the droplet laser cavity and the gain medium
Indistinguishable Photons from a Single Molecule
We report the results of coincidence counting experiments at the output of a
Michelson interferometer using the zero-phonon-line emission of a single
molecule at . Under continuous wave excitation, we observe the absence
of coincidence counts as an indication of two-photon interference. This
corresponds to the observation of Hong-Ou-Mandel correlations and proves the
suitability of the zero-phonon-line emission of single molecules for
applications in linear optics quantum computation.Comment: To appear in Phys. Rev. Let
An Efficient 2-Party Private Function Evaluation Protocol Based on Half Gates
The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Private function evaluation (PFE) is a special case of secure multi-party computation (MPC), where the function to be computed is known by only one party. PFE is useful in several real-life applications where an algorithm or a function itself needs to remain secret for reasons such as protecting intellectual property or security classification level. In this
paper, we focus on improving 2-party PFE based on symmetric cryptographic primitives. In this respect, we look back at the seminal PFE
framework presented by Mohassel and Sadeghian at Eurocrypt’13. We show how to adapt and utilize the well-known half gates garbling technique (Zahur et al., Eurocrypt’15) to their constant-round 2-party PFE scheme. Compared to their scheme, our resulting optimization significantly improves the efficiency of both the underlying Oblivious Evaluation of Extended Permutation (OEP) and secure 2-party computation (2PC) protocols, and yields a more than 40% reduction in overall communication cost (the computation time is also slightly decreased and the number of rounds remains unchanged)
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