22,196 research outputs found
Robust Speech Detection for Noisy Environments
This paper presents a robust voice activity detector (VAD) based on hidden Markov models (HMM) to improve speech recognition systems in stationary and non-stationary noise environments: inside motor vehicles (like cars or planes) or inside buildings close to high traffic places (like in a control tower for air traffic control (ATC)). In these environments, there is a high stationary noise level caused by vehicle motors and additionally, there could be people speaking at certain distance from the main speaker producing non-stationary noise. The VAD presented in this paper is characterized by a new front-end and a noise level adaptation process that increases significantly the VAD robustness for different signal to noise ratios (SNRs). The feature vector used by the VAD includes the most relevant Mel Frequency Cepstral Coefficients (MFCC), normalized log energy and delta log energy. The proposed VAD has been evaluated and compared to other well-known VADs using three databases containing different noise conditions: speech in clean environments (SNRs mayor que 20 dB), speech recorded in stationary noise environments (inside or close to motor vehicles), and finally, speech in non stationary environments (including noise from bars, television and far-field speakers). In the three cases, the detection error obtained with the proposed VAD is the lowest for all SNRs compared to Acero¿s VAD (reference of this work) and other well-known VADs like AMR, AURORA or G729 annex b
A dichotomy property for locally compact groups
We extend to metrizable locally compact groups Rosenthal's theorem describing
those Banach spaces containing no copy of . For that purpose, we transfer
to general locally compact groups the notion of interpolation () set,
which was defined by Hartman and Ryll-Nardzewsky [25] for locally compact
abelian groups. Thus we prove that for every sequence in a locally compact group , then either has a weak Cauchy subsequence or contains a subsequence
that is an set. This result is subsequently applied to obtain sufficient
conditions for the existence of Sidon sets in a locally compact group , an
old question that remains open since 1974 (see [32] and [20]). Finally, we show
that every locally compact group strongly respects compactness extending
thereby a result by Comfort, Trigos-Arrieta, and Wu [13], who established this
property for abelian locally compact groups.Comment: To appear in J. of Functional Analysi
Report on identifying a protocol to elicit flowering in Brachiaria humidicola with photoperiod management
Two Genotypes of Brachiaria humidicola (A and B) were planted on the grounds of CIAT headquarters in Palmira during 2018 – 2019, 10 lamps were placed in the lot to evaluate 6 different photoperiods (1 - 6) with Light in 2 different wavelength range (W.R.) α and β, for this, 17 samples were carried out on the variables height, vigor, chlorophyll content and number of inflorescences; a total of 93 field work were carried out to support the trial, finding that the photoperiod 5 in the W.R. β and 3 photoperiod in the W.R. α for the B genotype show significant differences (p <0.05, Tukey) with respect to the other treatments for height and number of inflorescences, performing the statistical analysis in the SAS software. As to the seed production, it was found that any light stimulus generates greater seed production, despite the conditions under which the crops were made and the method of harvest used. I order to refine the protocol and validate the results in bigger genotype sample another trial with the 2 most efficient treatments was proposed for 2020, focusing on number of inflorescences and seed production
Interpolation sets in spaces of continuous metric-valued functions
Let and be a topological space and metric space, respectively. If
denotes the set of all continuous functions from X to M, we say that a
subset of is an \emph{-interpolation set} if given any function
with relatively compact range in , there exists a map such that . In this paper, motivated by a result of Bourgain
in \cite{Bourgain1977}, we introduce a property, stronger than the mere
\emph{non equicontinuity} of a family of continuous functions, that isolates a
crucial fact for the existence of interpolation sets in fairly general
settings. As a consequence, we establish the existence of sets in every
nonprecompact subset of a abelian locally -groups. This implies
that abelian locally -groups strongly respects compactness
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