Time and Frequency Pruning for Speaker Identification

International audienceThis work is an attempt to refine decisions in speaker identification. A test utterance is divided into multiple time-frequency blocks on which a normalized likelihood score is calculated. Instead of averaging the block-likelihoods along the whole test utterance, some of them are rejected (pruning) and the final score is computed with a limited number of time-frequency blocks. The results obtained in the special case of time pruning lead the authors to experiment a joint time and frequency pruning approach. The optimal percentage of blocks pruned is learned on a tuning data set with the minimum identification error criterion. Validation of the time-frequency pruning process on 567 speakers leads to a significant error rate reduction (up to 41% reduction on TIMIT) for short training and test duration. ,QWURGXFWLRQ Mono-gaussian models for speaker recognition have been largely replaced by Gaussian Mixture Models (GMM) which are dedicated to modeling smaller clusters of speech. The Gaussian mixture modeling can be seen as a FRRSHUDWLRQ of models since the gaussian mixture density is a weighted linear combination of uni-modal gaussian densities. The work presented here is rather concerned with FRPSHWLWLRQ of models since different mono-gaussian models (corresponding to different frequency subbands) are applied to the test signal and the decision is made with the best or the N-best model scores. More precisely, a test utterance is divided into time-frequency blocks, each of them corresponding to a particular frequency subband and a particular time segment. During the recognition phase, the block scores are accumulated over the whole test utterance to compute a global score and take a final decision. In this work, we investigate accumulation using a hard threshold approach since some block scores are eliminated (pruning) and the final decision is taken with a subset of these scores. This approach should be robust in the case of a time-frequency localized noise since the least reliable time-frequency blocks can be removed. Even in the case of clean speech, some speaker test utterance blocks can be simply more similar to another speaker model than to the target speaker model itself. Removing these error-prone blocks should lead to a more robust decision. In 6HFWLRQ , a formalism is proposed to describe our block-based speaker recognition system. The potential of this approach is shown with a special case of the formalism: time pruning (6HFWLRQ). Experiments intended to find the optimal percentage of blocks pruned are described in 6HFWLRQ. The optimal parameters (percentage of blocks pruned) are validated on TIMIT and NTIMIT databases (6HFWLRQ). Finally, we summarize our main results and outline the potential advantages of the time-frequency pruning procedure in 6HFWLRQ .)RUPDOLVP 0RQRJDXVVLDQ µVHJPHQWDO ¶ PRGHOLQJ Let { } [ W W 0 1≤ ≤ be a sequence of M vectors resulting from the S-dimensional acoustic analysis of a speech signal uttered by speaker X. These vectors are summarized by the mean vector [ and the covariance matrix X: [ 0 [ ; 0 [ [ [

DISCRIMINANT BINARY DATA REPRESENTATION FOR SPEAKER RECOGNITION

ABSTRACT In supervector UBM/GMM paradigm, each acoustic file is represented by the mean parameters of a GMM model. This supervector space is used as a data representation space, which has a high dimensionality. Moreover, this space is not intrinsically discriminant and a complete speech segment is represented by only one vector, withdrawing mainly the possibility to take into account temporal or sequential information. This work proposes a new approach where each acoustic frame is represented in a discriminant binary space. The proposed approach relies on a UBM to structure the acoustic space in regions. Each region is then populated with a set of Gaussian models, denoted as "specificities", able to emphasize speaker specific information. Each acoustic frame is mapped in the discriminant binary space, turning "on" or "off" all the specificities to create a large binary vector. All the following steps, speaker reference extraction, likelihood estimation or decision take place in this binary space. Even if this work is a first step in this avenue, the experiments based on NIST SRE 2008 framework demonstrate the potential of the proposed approach. Moreover, this approach opens the opportunity to rethink all the classical processes using a discrete, binary view

Electrochemical synthesis of polypyrrole doped with graphene oxide and its electrochemical characterization as membrane material

Polypyrrole (PPy) doped with graphene oxide (GO) has been electrochemically obtained by potentiostatic synthesis and its electrochemical behavior as membrane material has been studied for the first time. Fourier transform infrared spectroscopy with attenuated total reflection showed the formation of the hybrid material due to presence of PPy and GO bands. Field emission scanning electron microscopy micrographs showed the effective incorporation of GO sheets and the formation of a 3-D porous material with high surface area. Scanning electrochemical microscopy of PPy/GO films showed positive feedback close to the ideal conducting behavior, indicating a good electroactivity. Electrochemical impedance spectroscopy (EIS) was employed to measure the electrochemical properties of the coatings by two-, three-, and four-electrode configurations. The electronic conductivity of PPy/GO film, measured between two metallic conductors, was 4.7·10−6 S/cm. Its ionic conductivity was superior (1.6·10−3 S/cm) due to the high porosity of the material as demonstrated by cyclic voltammetry and EIS measurements, where the PPy/GO film was employed as a free-standing membrane. The diffusion-migration rate of tetramethylammonium chloride was very similar to sodium chloride when present in the same concentration, which indicated no influence of the size of the electrolyte conductor due to the high porosity. © 2016 Elsevier B.V. All rights reserved.Authors wish to thank the Spanish Ministerio de Ciencia e Innovacion (contract CTM2011-23583) for the financial support. J. Molina is grateful to the Conselleria d'Educacio, Formacio i Ocupacio (Generalitat Valenciana) for the Programa VALi+D Postdoctoral Fellowship (APOSTD/2013/056). A.I. del Rio is grateful to the Spanish Ministerio de Ciencia y Tecnologia for her FPI fellowship. Electron Microscopy Service of the UPV (Universitat Politecnica de Valencia) is gratefully acknowledged for help with FESEM and EDX characterization.Molina Puerto, J.; Bonastre Cano, JA.; Fernández Sáez, J.; Del Río García, AI.; Cases Iborra, FJ. (2016). Electrochemical synthesis of polypyrrole doped with graphene oxide and its electrochemical characterization as membrane material. Synthetic Metals. 220:300-310. https://doi.org/10.1016/j.synthmet.2016.06.028S30031022

Chemical and electrochemical study of fabrics coated with reduced graphene oxide

Polyester fabrics coated with reduced graphene oxide (RGO) have been obtained and later characterized by means of chemical and electrochemical techniques. X-ray photoelectron spectroscopy showed a decrease of the oxygen content as well as an increase of the sp2 fraction after chemical reduction of graphene oxide (GO). The electrical conductivity was measured by electrochemical impedance spectroscopy (EIS) and showed a decrease of 5 orders of magnitude in the resistance (¿) when GO was reduced to RGO. The phase angle also changed from 90° for PES-GO (capacitative behavior) to 0° for RGO coated fabrics (resistive behavior). In general an increase in the number of RGO layers produced an increase of the conductivity of the fabrics. EIS measurements in metal/sample/electrolyte configuration showed better electrocatalytic properties and faster diffusion rate for RGO specimens. Scanning electrochemical microscopy was employed to test the electroactivity of the different fabrics obtained. The sample coated with GO was not conductive since negative feedback was obtained. When GO was reduced to RGO the sample behaved like a conducting material since positive feedback was obtained. Approach curves indicated that the redox mediator had influence on the electrochemical response. The Fe(CN)63¿/4¿ redox mediator produced a higher electrochemical response than Ru(NH3)63+/2+ one.Authors thank to the Spanish Ministerio de Ciencia e Innovacion (contract CTM2011-23583) and Universitat Politecnica de Valencia (Vicerrectorado de Investigacion PAID-06-10 contract 003-233) for the financial support. J. Molina is grateful to the Conselleria d'Educacio (Generalitat Valenciana) for the FPI fellowship. A.I. del Rio is grateful to the Spanish Ministerio de Ciencia y Tecnologia for the FPI fellowship. J.C. Galvan is gratefully acknowledged for help with EIS measurements and data analysis.Molina Puerto, J.; Fernández Sáez, J.; Del Río García, AI.; Bonastre Cano, JA.; Cases Iborra, FJ. (2013). Chemical and electrochemical study of fabrics coated with reduced graphene oxide. Applied Surface Science. 279:46-54. https://doi.org/10.1016/j.apsusc.2013.04.020S465427

Recommendations for the use of next-generation sequencing (NGS) for patients with metastatic cancers: a report from the ESMO Precision Medicine Working Group

Next-generation sequencing (NGS) allows sequencing of a high number of nucleotides in a short time frame at an affordable cost. While this technology has been widely implemented, there are no recommendations from scientific societies about its use in oncology practice. The European Society for Medical Oncology (ESMO) is proposing three levels of recommendations for the use of NGS. Based on the current evidence, ESMO recommends routine use of NGS on tumour samples in advanced non-squamous non-small-cell lung cancer (NSCLC), prostate cancers, ovarian cancers and cholangiocarcinoma. In these tumours, large multigene panels could be used if they add acceptable extra cost compared with small panels. In colon cancers, NGS could be an alternative to PCR. In addition, based on the KN158 trial and considering that patients with endometrial and small-cell lung cancers should have broad access to anti-programmed cell death 1 (anti-PD1) antibodies, it is recommended to test tumour mutational burden (TMB) in cervical cancers, well- and moderately-differentiated neuroendocrine tumours, salivary cancers, thyroid cancers and vulvar cancers, as TMB-high predicted response to pembrolizumab in these cancers. Outside the indications of multigene panels, and considering that the use of large panels of genes could lead to few clinically meaningful responders, ESMO acknowledges that a patient and a doctor could decide together to order a large panel of genes, pending no extra cost for the public health care system and if the patient is informed about the low likelihood of benefit. ESMO recommends that the use of off-label drugs matched to genomics is done only if an access programme and a procedure of decision has been developed at the national or regional level. Finally, ESMO recommends that clinical research centres develop multigene sequencing as a tool to screen patients eligible for clinical trials and to accelerate drug development, and prospectively capture the data that could further inform how to optimise the use of this technology

Conducting fabrics of polyester coated with polypyrrole and doped with graphene oxide

Polyester (PES) has been coated with polypyrrole (PPy) to produce conducting fabrics. Graphene oxide (GO) has been used in different concentrations (10, 20 and 30% weight) as counter ion to neutralize the positive charges of the PPy structure. Fourier transform infrared spectroscopy with attenuated total reflection (FTIR-ATR), energy dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS) of the PPy/GO powders corroborated the incorporation of GO as counter ion due to the presence of O in the EDX spectrum, as well as an excess of C, arising from GO contribution. The doping level (N+/N) decreased with the GO content. Field emission scanning electron microscopy (FESEM) showed the formation of the PPy/GO coating and the incorporation of GO in the composite. Electrochemical impedance spectroscopy (EIS) in solid state and solution, cyclic voltammetry (CV) and scanning electrochemical microscopy (SECM) were used to test the electrical properties and electroactivity of the fabrics. There was a decrease in the electrical properties and electroactivity as the GO content increased. The conductivity of the fabrics could be tuned by varying the GO content.Spanish Ministerio de Ciencia e Innovación (contract CTM2011-23583) for the financial support. Conselleria d'Educació, Formació i Ocupació (Generalitat Valenciana) for the Programa VALi+D Postdoctoral Fellowship. C2011-UMINHO-2C2T-01 FCT funding from Programa Compromisso para a Ciência 2008, Portugal. XPS studies were performed at CEMUP (University of Porto, Portugal) facilities. Electron Microscopy Service of the UPV (Universitat Politècnica de València) is gratefully acknowledged for help with FESEM and EDX characterization

Modified carbon fabric electrodes: preparation and electrochemical behavior toward amaranth electrolysis

The final publication is available at Springer via http://dx.doi.org/10.1007/s10800-014-0769-9The electrochemical behavior of non-modified, Pt-modified, and Pt/polyaniline-modified carbon fiber textile electrodes was studied through a series of electrolyses, under potentiostatic conditions, on an amaranth/sulfuric solution in the presence or absence of chloride ion. The morphology of the dispersed Pt, PANI, and PANI/Pt coatings was analyzed by scanning electron microscopy. Scanning electrochemical microscopy confirmed that the textile surface was effectively modified by the electrocatalytic material. Color removal reached values above 90 % in both electroreduction and electrooxidation processes. The amaranth electroreductions carried out with the non-modified electrode showed better charge efficiency than those with the Pt-modified textile electrode. The electrooxidations with Pt-modified textile electrodes showed a significant reduction in electrolysis time. Ultraviolet-visible and Fourier transform infrared with attenuated total reflection spectra enabled the electrochemical behavior of the non-modified and Pt/PANI-modified electrodes to be distinguished.The authors wish to acknowledge to the Spanish Ministerio de Ciencia e Innovacion (contract CTM2011-23583) and Universitat Politecnica de Valencia (Vicerrectorado de Investigacion PAID-06-10 contract 003-233) for the financial support; and as well as Carbongen S. A. (Cocentaina, Spain), who kindly donated the activated carbon fabric. J. Molina is grateful to the Conselleria d'Educacio, Formacio i Ocupacio (Generalitat Valenciana) for the Programa VALi+D Postdoctoral Fellowship. A.I. del Rio is grateful to the Spanish Ministerio de Ciencia y Tecnologia for the FPI fellowship.Fernández Sáez, J.; Del Río García, AI.; Molina Puerto, J.; Bonastre Cano, JA.; Cases Iborra, FJ. (2015). Modified carbon fabric electrodes: preparation and electrochemical behavior toward amaranth electrolysis. Journal of Applied Electrochemistry. 45(3):263-272. https://doi.org/10.1007/s10800-014-0769-9S263272453Marsh H, Reinoso FR (2000) Sciences of carbon materials. Universidad de Alicante, AlicanteKinoshita K (1998) Carbon: electrochemical and physicochemical properties. Wiley, New York, pp 293–387Burchell TD (1999) Carbon materials for advances technologies. Pergamon, AmsterdamDomínguez SD, Pardilla JA, Murcia AB, Morallón E, Amorós DC (2008) Electrochemical deposition of Pt nanoparticles on different carbon supports and conducting polymers. J Appl Electrochem 38:259–268Kezhong W, Xu M, Xindong W, Jingling L (2005) Pt–Polyaniline-modified carbon fiber electrode for the electrooxidation of methanol. Rare Met 24:33–36Wu G, Li L, Li JH, Xu BQ (2006) Methanol electrooxidation on Pt particles dispersed into PANI/SWNT composite films. J Power Sources 155:118–127Singh RN, Awasthi R, Tiwari SK (2010) Electro-catalytic activities of binary nano-composites of Pt and nano-carbon/multiwall carbon nanotube for methanol electro-electrooxidation. Open Catal J 3:50–57Zhiani M, Rezaei B, Jalili J (2010) Methanol electro-electrooxidation on Pt/C modified by polyaniline nanofibers for DMFC applications. Int J Hydrogen Energ 35:9298–9305Laborde H, Léger J-M, Lamy C (1994) Electrocatalytic electrooxidation of methanol and C1 molecules on highly dispersed electrodes. Part 1: Pt in polyaniline. J Appl Electrochem 24:219–226Niu L, Li Q, Wei F, Wu S, Liu P, Cao X (2005) Electrocatalytic behaviour of Pt-modified polyaniline electrode for methanol electrooxidation: effect of Pt deposition modes. J Electroanal Chem 578:331–337Huang LM, Tang WR, Wen TCh (2007) Spatially electrodeposited Pt in polyaniline doped with poly(styrene sulfonic acid) for methanol electrooxidation. J Power Sources 164:519–526Fernández J, Molina J, del Río AI, Bonastre J, Cases FJ (2012) Synthesis and characterization of electrochemically platinum–polyaniline modified carbon textile electrodes. Int J Electrochem Sci 7:10175–10189Snehalatha M, Ravikumar C, Sekar N, Jayakumar SV, Joe H (2008) FT–Raman, IR and UV–visible spectral investigations and ab initio computations of a nonlinear food dye amaranth. J Raman Spectrosc 39:928–936Rajendran L, Ananthi SP (2004) Analysis of positive feedback currents at the scanning electrochemical microscope. J Electroanal Chem 561:113–118Niu L, Li Q, Wei F, Chen X, Wang W (2003) Formation optimization of Pt-modified polyaniline films for the electrocatalytic electrooxidation of methanol. Synthetic Met 139:271–276Sala M, del Río AI, Molina J, Cases F, Gutierrez-Bouzán MC (2012) Influence of cell design and electrode materials on the decoloration of dyeing effluents. Int J Electrochem Sc 7:12470–12488Priyantha N, Malavipathirana S (1996) Effect of chloride ions on the electrochemical behavior of platinum surfaces. J Natn Sci Coun Sri Lanka 24:237–246Rajeev J, Nidhi Sh, Keisham R (2009) Electrochemical treatment of pharmaceutical azo dye amaranth from waste water. J Appl Electochem 39:577–582Nadupalli S, Koorbanally N, Jonnalagadda SB (2011) Kinetics and mechanism of the oxidation of amaranth with hypochlorite. J Phys Chem A 115:7948–795

Polyaniline coated conducting fabrics : chemical and electrochemical characterization

Polyaniline coated conducting fabrics have been obtained by chemical oxidation of aniline by potassium peroxydisulfate on polyester fabrics. Two different acids have been employed to carry out the synthesis (HCl and H2SO4), obtaining the best results of conductivity with the latter one. The conducting fabrics have been characterized chemically by means of Fourier transform infrared spectroscopy with attenuated total reflection (FTIR-ATR), energy dispersive X-Ray (EDX) and X-ray photoelectron spectroscopy (XPS). The morphology of the coatings has been observed by means of scanning electron microscopy (SEM). The conducting properties of the fabrics have been measured by means of electrochemical impedance spectroscopy (EIS). The electrochemical characterization has been carried out by means of cyclic voltammetry (CV) and scanning electrochemical microscopy (SECM). The conducting fabrics have also shown electrochromic properties, changing its color from green yellowish at −1 V to dark green at +2 V. The durability of the coating has been evaluated by means of washing and rubbing fastness tests.Authors thank to the Spanish Ministerio de Ciencia e Innovacion and European Union Funds (FEDER) (contract CTM2010-18842-C02-02) and Universitat Politecnica de Valencia (Primeros Proyectos de Investigacion (PAID-06-10)) for the financial support. J. Molina is grateful to the Conselleria d'Educacio (Generalitat Valenciana) for the FPI fellowship

Efficacy and safety of trimodulin, a novel polyclonal antibody preparation, in patients with severe community-acquired pneumonia: a randomized, placebo-controlled, double-blind, multicenter, phase II trial (CIGMA study)

Purpose The CIGMA study investigated a novel human polyclonal antibody preparation (trimodulin) containing ~ 23% immunoglobulin (Ig) M, ~ 21% IgA, and ~ 56% IgG as add-on therapy for patients with severe community-acquired pneumonia (sCAP). Methods In this double-blind, phase II study (NCT01420744), 160 patients with sCAP requiring invasive mechanical ventilation were randomized (1:1) to trimodulin (42 mg IgM/kg/day) or placebo for five consecutive days. Primary endpoint was ventilator-free days (VFDs). Secondary endpoints included 28-day all-cause and pneumonia-related mortality. Safety and tolerability were monitored. Exploratory post hoc analyses were performed in subsets stratified by baseline C-reactive protein (CRP; ≥ 70 mg/L) and/or IgM (≤ 0.8 g/L). Results Overall, there was no statistically significant difference in VFDs between trimodulin (mean 11.0, median 11 [n = 81]) and placebo (mean 9.6; median 8 [n = 79]; p = 0.173). Twenty-eight-day all-cause mortality was 22.2% vs. 27.8%, respectively (p = 0.465). Time to discharge from intensive care unit and mean duration of hospitalization were comparable between groups. Adverse-event incidences were comparable. Post hoc subset analyses, which included the majority of patients (58–78%), showed significant reductions in all-cause mortality (trimodulin vs. placebo) in patients with high CRP, low IgM, and high CRP/low IgM at baseline. Conclusions No significant differences were found in VFDs and mortality between trimodulin and placebo groups. Post hoc analyses supported improved outcome regarding mortality with trimodulin in subsets of patients with elevated CRP, reduced IgM, or both. These findings warrant further investigation

The I4U Mega Fusion and Collaboration for NIST Speaker Recognition Evaluation 2016

The 2016 speaker recognition evaluation (SRE'16) is the latest edition in the series of benchmarking events conducted by the National Institute of Standards and Technology (NIST). I4U is a joint entry to SRE'16 as the result from the collaboration and active exchange of information among researchers from sixteen Institutes and Universities across 4 continents. The joint submission and several of its 32 sub-systems were among top-performing systems. A lot of efforts have been devoted to two major challenges, namely, unlabeled training data and dataset shift from Switchboard-Mixer to the new Call My Net dataset. This paper summarizes the lessons learned, presents our shared view from the sixteen research groups on recent advances, major paradigm shift, and common tool chain used in speaker recognition as we have witnessed in SRE'16. More importantly, we look into the intriguing question of fusing a large ensemble of sub-systems and the potential benefit of large-scale collaboration.Peer reviewe