2,924 research outputs found
Entropic measure of directional emissions in microcavity lasers
We propose a noble notion of the directional emission in microcavity lasers.
First, Shannon entropy of the far-field profiles in the polar coordinate can
quantify the degree of unidirectionality of the emission, while previous
notions about the unidirectionality can not efficiently measure in the robust
range against a variation of the deformation parameter. Second, a divergence
angle of the directional emission is defined phenomenologically in terms of
full width at half maximum, and it is barely applicable to a complicated peak
structure. However, Shannon entropy of semi-marginal probability of the
far-field profiles in the cartesian coordinate can present equivalent results,
and moreover it is applicable to even the cases with a complicated peak
structure of the emission
Interactive media server with media synchronized raid storage system
We propose an efficient placement algorithm and per-disk prefetching method to effectively support interactive operations in the media server. Our placement policy is incorporated with an encoder having a special bitcount control scheme that repeatedly tunes quantization parameters to adjust the bitcounts of video frames. This encoder can generate coded frames whose sizes are synchronized with the RAID stripe size, so that when various fast-forward levels are accessed we can reduce the seek and rotational latency and enhance the disk throughput of each disk in the RAID system. In the experimental results, the proposed placement policy and bitrate control scheme can significantly improve the average service time, which can enlarge the capacity of the interactive media server
Isolation of p-hydroxycinnamaldehyde as an antibacterial substance from the saw fly, Acantholyda parki S.
AbstractWe purified an antibacterial substance from larvae of the saw fly, Acantholyda parki S., and identified its molecular structure as p-hydroxycinnamaldehyde. We then synthesized it by reduction of p-hydroxycinnamic acid. The antibacterial activity of the synthetic p-hydroxycinnamaldehyde was equal to that of the authentic substance. This molecule was found to have a broad antibacterial spectrum against not only Gram-negative, but also Gram-positive bacteria. Furthermore, it showed antifungal activity against Candida albicans. We suggest that this substance may play a role in the defense system of this insect. This is the first report of p-hydroxycinnamaldehyde of animal origin
Decomposed entropy and estimation of output power in deformed microcavity lasers
Park et al. [Phys. Rev. A 106, L031504 (2022)] showed that the Shannon
entropy of the probability distribution of a single random variable for
far-field profiles (FFPs) in deformed microcavity lasers can efficiently
measure the directionality of deformed microcavity lasers. In this study, we
instead consider two random variables of FFPs with joint probability
distributions and introduce the decomposed (Shannon) entropy for the peak
intensity of directional emissions. This provides a new foundation such that
the decomposed entropy can estimate the degree of the output power at given
FFPs without any further information.Comment: 7 pages, 5 figure
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