156 research outputs found
Detection of speech signal in strong ship-radiated noise based on spectrum entropy
Comparing the frequency spectrum distributions calculated from several successive frames, the change of the frequency spectrum of speech frames between successive frames is larger than that of the ship-radiated noise. The aim of this work is to propose a novel speech detection algorithm in strong ship-radiated noise. As inaccurate sentence boundaries are a major cause in automatic speech recognition in strong noise background. Hence, based on that characteristic, a new feature repeating pattern of frequency spectrum trend (RPFST) was calculated based on spectrum entropy. Firstly, the speech is detected roughly with the precision of 1Â s by calculating the feature RPFST. Then, the detection precision is up to 20Â ms, the length of frames, by method of frame shifting. Finally, benchmarked on a large measured data set, the detection accuracy (92Â %) is achieved. The experimental results show the feasibility of the algorithm to all kinds of speech and ship-radiated noise
Detection of speech signal in strong ship-radiated noise based on spectrum entropy
Comparing the frequency spectrum distributions calculated from several successive frames, the change of the frequency spectrum of speech frames between successive frames is larger than that of the ship-radiated noise. The aim of this work is to propose a novel speech detection algorithm in strong ship-radiated noise. As inaccurate sentence boundaries are a major cause in automatic speech recognition in strong noise background. Hence, based on that characteristic, a new feature repeating pattern of frequency spectrum trend (RPFST) was calculated based on spectrum entropy. Firstly, the speech is detected roughly with the precision of 1Â s by calculating the feature RPFST. Then, the detection precision is up to 20Â ms, the length of frames, by method of frame shifting. Finally, benchmarked on a large measured data set, the detection accuracy (92Â %) is achieved. The experimental results show the feasibility of the algorithm to all kinds of speech and ship-radiated noise
Optimization of phenoxazinone synthase production by response surface methodology and its application in Congo red decolourization
Background: Enzymatic decolourization has been recently proposed as a
promising and eco-friendly method for treatment of synthetic
dye-contaminated wastewaters. However, the processes require large
quantities of enzymes, attracting significant attention in developing
efficient methods for mass production of multifunctional enzymes.
Several methods such as response surface methodology (RSM) and
orthogonal experiment have been applied to optimize the parameters in
bioprocesses for enzyme production. Results: In the present study, a
laccase-like enzyme, phenoxazinone synthase (PHS) originated from
Streptomyces antibioticus was recombinantly expressed in Escherichia
coli BL21 (DE3). The production of PHS in E. coli BL21 was optimized
by response surface methodology based on Box-Behnken design. A full
third-order polynomial model was generated by data analysis with
Statistica 8.0 in which the optimal conditions for PHS production were
calculated to be 1.525 mM CuSO4 and 16.096 hrs induction at temperature
of 29.88oC. The highest PHS production under optimal conditions was
calculated to be 4098.51 U/l using the established model. Average PHS
production obtained from actual production processes carried out under
the calculated optimal conditions was 4052.00 U/l, very close to the
value predicted by the model. Crude PHS was subsequently tested in
Congo red decolourization which exhibited a low decolourization rate of
27% without mediator. Several mediators were found to improve
PHS-catalyzed Congo red decolourization, with the highest rate of
73.89% obtained with
2,2\u81f-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) as
mediator under optimized conditions of 4000 U/l PHS activity, 10
\u3bcM ABTS, 100 \u3bcM Congo red, and 8 hrs reaction time.
Conclusion: Our results indicated that PHS recombinantly produced in E.
coli BL21 was a prospective enzyme for decolorizing reactive dye Congo
red
Optimized properties of innovative ElectroChromic Device using ITO / Ag / ITO electrodes
The âDielectric/Metal/Dielectricâ (DMD) stacked films being used as transparent and conductive (TC) electrodes, have demonstrated excellent application in the ElectroChromic (EC) process and devices. In this work, multilayers (IAI) made of 50âŻnm of Indium Tin Oxide (ITO)/5âŻnm of metallic silver (Ag)/30âŻnm of ITO that exhibit band-gap, low resistance of 7.4âŻÎ© and the high figure of merit of 9.9âŻĂâŻ10â3âŻÎ©â1 were introduced in a complete five-layer Glass/IAI/NiOx/LiClO4-PC-PMMA/WO3/IAI/Glass ElectroChromic Device (ECD). The single IAI electrode as well as the two actives EC layers Glass/IAI/NiOx and Glass/IAI/WO3 were firstly characterized for their TC and EC properties respectively. Then, the EC properties of the complete five-layer ECD were analyzed. Fast response time (2.02âŻs for the bleaching and 2.25âŻs for complete coloration), wide optical modulation in the visible light region (âŒ55% at 550âŻnm), long lifetime (more than 6000âŻs), large capacity and good stability as well as high coloration efficiency (31.7âŻcm2âŻCâ1) were obtained. The improved EC performance of ECD were related to the good electrical and optical properties of IAI electrode
Direct Measurements of the Branching Fractions for and and Determinations of the Form Factors and
The absolute branching fractions for the decays and
are determined using singly
tagged sample from the data collected around 3.773 GeV with the
BES-II detector at the BEPC. In the system recoiling against the singly tagged
meson, events for and events for decays are observed. Those yield
the absolute branching fractions to be and . The
vector form factors are determined to be
and . The ratio of the two form
factors is measured to be .Comment: 6 pages, 5 figure
Measurements of J/psi Decays into 2(pi+pi-)eta and 3(pi+pi-)eta
Based on a sample of 5.8X 10^7 J/psi events taken with the BESII detector,
the branching fractions of J/psi--> 2(pi+pi-)eta and J/psi-->3(pi+pi-)eta are
measured for the first time to be (2.26+-0.08+-0.27)X10^{-3} and
(7.24+-0.96+-1.11)X10^{-4}, respectively.Comment: 11 pages, 6 figure
BESII Detector Simulation
A Monte Carlo program based on Geant3 has been developed for BESII detector
simulation. The organization of the program is outlined, and the digitization
procedure for simulating the response of various sub-detectors is described.
Comparisons with data show that the performance of the program is generally
satisfactory.Comment: 17 pages, 14 figures, uses elsart.cls, to be submitted to NIM
Measurement of branching fractions for the inclusive Cabibbo-favored ~K*0(892) and Cabibbo-suppressed K*0(892) decays of neutral and charged D mesons
The branching fractions for the inclusive Cabibbo-favored ~K*0 and
Cabibbo-suppressed K*0 decays of D mesons are measured based on a data sample
of 33 pb-1 collected at and around the center-of-mass energy of 3.773 GeV with
the BES-II detector at the BEPC collider. The branching fractions for the
decays D+(0) -> ~K*0(892)X and D0 -> K*0(892)X are determined to be BF(D0 ->
\~K*0X) = (8.7 +/- 4.0 +/- 1.2)%, BF(D+ -> ~K*0X) = (23.2 +/- 4.5 +/- 3.0)% and
BF(D0 -> K*0X) = (2.8 +/- 1.2 +/- 0.4)%. An upper limit on the branching
fraction at 90% C.L. for the decay D+ -> K*0(892)X is set to be BF(D+ -> K*0X)
< 6.6%
Measurements of the Mass and Full-Width of the Meson
In a sample of 58 million events collected with the BES II detector,
the process J/ is observed in five different decay
channels: , , (with ), (with
) and . From a combined fit of all five
channels, we determine the mass and full-width of to be
MeV/ and
MeV/.Comment: 9 pages, 2 figures and 4 table. Submitted to Phys. Lett.
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