2,638 research outputs found
Time-Contrastive Learning Based Deep Bottleneck Features for Text-Dependent Speaker Verification
There are a number of studies about extraction of bottleneck (BN) features
from deep neural networks (DNNs)trained to discriminate speakers, pass-phrases
and triphone states for improving the performance of text-dependent speaker
verification (TD-SV). However, a moderate success has been achieved. A recent
study [1] presented a time contrastive learning (TCL) concept to explore the
non-stationarity of brain signals for classification of brain states. Speech
signals have similar non-stationarity property, and TCL further has the
advantage of having no need for labeled data. We therefore present a TCL based
BN feature extraction method. The method uniformly partitions each speech
utterance in a training dataset into a predefined number of multi-frame
segments. Each segment in an utterance corresponds to one class, and class
labels are shared across utterances. DNNs are then trained to discriminate all
speech frames among the classes to exploit the temporal structure of speech. In
addition, we propose a segment-based unsupervised clustering algorithm to
re-assign class labels to the segments. TD-SV experiments were conducted on the
RedDots challenge database. The TCL-DNNs were trained using speech data of
fixed pass-phrases that were excluded from the TD-SV evaluation set, so the
learned features can be considered phrase-independent. We compare the
performance of the proposed TCL bottleneck (BN) feature with those of
short-time cepstral features and BN features extracted from DNNs discriminating
speakers, pass-phrases, speaker+pass-phrase, as well as monophones whose labels
and boundaries are generated by three different automatic speech recognition
(ASR) systems. Experimental results show that the proposed TCL-BN outperforms
cepstral features and speaker+pass-phrase discriminant BN features, and its
performance is on par with those of ASR derived BN features. Moreover,....Comment: Copyright (c) 2019 IEEE. Personal use of this material is permitted.
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Vocal Tract Length Perturbation for Text-Dependent Speaker Verification with Autoregressive Prediction Coding
In this letter, we propose a vocal tract length (VTL) perturbation method for
text-dependent speaker verification (TD-SV), in which a set of TD-SV systems
are trained, one for each VTL factor, and score-level fusion is applied to make
a final decision. Next, we explore the bottleneck (BN) feature extracted by
training deep neural networks with a self-supervised objective, autoregressive
predictive coding (APC), for TD-SV and compare it with the well-studied
speaker-discriminant BN feature. The proposed VTL method is then applied to APC
and speaker-discriminant BN features. In the end, we combine the VTL
perturbation systems trained on MFCC and the two BN features in the score
domain. Experiments are performed on the RedDots challenge 2016 database of
TD-SV using short utterances with Gaussian mixture model-universal background
model and i-vector techniques. Results show the proposed methods significantly
outperform the baselines.Comment: Copyright (c) 2021 IEEE. Personal use of this material is permitted.
Permission from IEEE must be obtained for all other uses, in any current or
future media, including reprinting/republishing this material for advertising
or promotional purposes, creating new collective works, for resale or
redistribution to servers or lists, or reuse of any copyrighted component of
this work in other work
Identifying Improved Sites for Heterologous Gene Integration Using ATAC-seq
Constructing efficient cellular factories often requires integration of heterologous pathways for synthesis of novel compounds and improved cellular productivity. Few genomic sites are routinely used, however, for efficient integration and expression of heterologous genes, especially in nonmodel hosts. Here, a data-guided framework for informing suitable integration sites for heterologous genes based on ATAC-seq was developed in the nonmodel yeast Komagataella phaffii. Single-copy GFP constructs were integrated using CRISPR/Cas9 into 38 intergenic regions (IGRs) to evaluate the effects of IGR size, intensity of ATAC-seq peaks, and orientation and expression of adjacent genes. Only the intensity of accessibility peaks was observed to have a significant effect, with higher expression observed from IGRs with low- to moderate-intensity peaks than from high-intensity peaks. This effect diminished for tandem, multicopy integrations, suggesting that the additional copies of exogenous sequence buffered the transcriptional unit of the transgene against effects from endogenous sequence context. The approach developed from these results should provide a basis for nominating suitable IGRs in other eukaryotic hosts from an annotated genome and ATAC-seq data
Agave: A promising feedstock for biofuels in the water-energy-food-environment (WEFE) nexus
This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordThe aim of this study was to conduct the first comprehensive life cycle assessment and economic analysis on ethanol produced from agave. Compositional and field data from a field experiment in Queensland, Australia was used. Our study shows that ethanol yields from agave (7414 L/ha/year) are comparable to Brazilian sugarcane (9900/L/ha/year) and higher than US corn ethanol (3800/L/ha/year). Furthermore, agave outperforms current first generation biofuel crops in water-related impacts, including Freshwater Eutrophication (96% lower than corn and 88% lower than sugarcane), Marine Ecotoxicity (59% lower than corn and 53% lower than sugarcane) and Water Consumption (46% lower than corn and 69% lower than sugarcane). The life cycle fossil energy use (Fossil Resource Scarcity) for agave is 58% lower than corn and 6% higher than sugarcane. The Global Warming impact for agave is also 62% and 30% lower than that of corn and sugarcane, respectively. Although its Land Use impact, measured by land occupied per unit ethanol output, is 98% higher than corn and 2% higher than sugarcane, agave can be grown on arid land that is not suitable for food crops. The economic analysis suggests that first generation ethanol production from agave is not commercially viable without government support. Overall, the results show that agave is promising for biofuel production in the water-energy-food-environment context.Engineering and Physical Sciences Research Council (EPSRC)Natural Environment Research Council (NERC
Easy on that trigger dad: a study of long term family photo retrieval
We examine the effects of new technologies for digital photography on people's longer term storage and access to collections of personal photos. We report an empirical study of parents' ability to retrieve photos related to salient family events from more than a year ago. Performance was relatively poor with people failing to find almost 40% of pictures. We analyze participants' organizational and access strategies to identify reasons for this poor performance. Possible reasons for retrieval failure include: storing too many pictures, rudimentary organization, use of multiple storage systems, failure to maintain collections and participants' false beliefs about their ability to access photos. We conclude by exploring the technical and theoretical implications of these findings
Differentiating Non-Motor Symptoms in Parkinson's Disease from Controls and Hemifacial Spasm
10.1371/journal.pone.0049596PLoS ONE82
How selection and weighting of astrometric observations influence the impact probability. Asteroid (99942) Apophis case
The aim is to show that in case of low probability of asteroid collision with
Earth, the appropriate selection and weighing of the data are crucial for the
impact investigation, and to analyze the impact possibilities using extensive
numerical simulations. By means of the Monte Carlo special method a large
number of ``clone'' orbits have been generated. A full range of orbital
elements in the 6-dimensional parameter space, e.g. in the entire confidence
region allowed by the observational material has been examined. On the basis of
1000 astrometric observations of (99942) Apophis, the best solution for the
geocentric encounter distance of 6.065\pm 0.081 R_{Earth} were derived for the
close encounter with the Earth on April 13, 2029. The present uncertainties
allow for the special configurations (``keyholes'') during these encounter
which may lead to the very close encounters in the future approaches of
Apophis. Two groups of keyholes are connected with the close encounter with the
Earth in 2036 (within the minimal distance of 5.7736-5.7763 R_{Earth} on April
13, 2029) and 2037 (within the minimal distance of 6.3359-6.3488 R_{Earth}).
The nominal orbits for our most accurate models run almost exactly in the
middle between these two impact keyhole groups. A very small keyhole for the
impact in 2076 has been found between these groups at the minimal distance of
5.97347 R_{Earth} (close to the nominal orbit)
Exogenous WNT5A and WNT11 proteins rescue CITED2 dysfunction in mouse embryonic stem cells and zebrafish morphants
Mutations and inadequate methylation profiles of CITED2 are associated with human congenital heart disease (CHD). In mouse, Cited2 is necessary for embryogenesis, particularly for heart development, and its depletion in embryonic stem cells (ESC) impairs cardiac differentiation. We have now determined that Cited2 depletion in ESC affects the expression of transcription factors and cardiopoietic genes involved in early mesoderm and cardiac specification. Interestingly, the supplementation of the secretome prepared from ESC overexpressing CITED2, during the onset of differentiation, rescued the cardiogenic defects of Cited2-depleted ESC. In addition, we demonstrate that the proteins WNT5A and WNT11 held the potential for rescue. We also validated the zebrafish as a model to investigate cited2 function during development. Indeed, the microinjection of morpholinos targeting cited2 transcripts caused developmental defects recapitulating those of mice knockout models, including the increased propensity for cardiac defects and severe death rate. Importantly, the co-injection of anti-cited2 morpholinos with either CITED2 or WNT5A and WNT11 recombinant proteins corrected the developmental defects of Cited2-morphants. This study argues that defects caused by the dysfunction of Cited2 at early stages of development, including heart anomalies, may be remediable by supplementation of exogenous molecules, offering the opportunity to develop novel therapeutic strategies aiming to prevent CHD.AgĆŖncia financiadora:
FundaĆ§Ć£o para a CiĆŖncia e a Tecnologia (FCT)
ComissĆ£o de CoordenaĆ§Ć£o e Desenvolvimento Regional do Algarve (CCDR Algarve)
ALG-01-0145-FEDER-28044; DFG 568/17-2 Algarve Biomedical Center (ABC)
Municipio de LoulƩinfo:eu-repo/semantics/publishedVersio
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