Recognizing Voice Over IP: A Robust Front-End for Speech Recognition on the World Wide Web

The Internet Protocol (IP) environment poses two relevant sources of distortion to the speech recognition problem: lossy speech coding and packet loss. In this paper, we propose a new front-end for speech recognition over IP networks. Specifically, we suggest extracting the recognition feature vectors directly from the encoded speech (i.e., the bit stream) instead of decoding it and subsequently extracting the feature vectors. This approach offers two significant benefits. First, the recognition system is only affected by the quantization distortion of the spectral envelope. Thus, we are avoiding the influence of other sources of distortion due to the encoding-decoding process. Second, when packet loss occurs, our front-end becomes more effective since it is not constrained to the error handling mechanism of the codec. We have considered the ITU G.723.1 standard codec, which is one of the most preponderant coding algorithms in voice over IP (VoIP) and compared the proposed front-end with the conventional approach in two automatic speech recognition (ASR) tasks, namely, speaker-independent isolated digit recognition and speaker-independent continuous speech recognition. In general, our approach outperforms the conventional procedure, for a variety of simulated packet loss rates. Furthermore, the improvement is higher as network conditions worsen.Publicad

Family education and support for families at psychosocial risk in Europe: Evidence from a survey of international experts

First published online: 11 October 2018There is overwhelming consensus among policy makers, academics, and professionals about the need to support families in their childrearing tasks. Consequently, European countries have been encouraged to develop family support interventions aimed at guaranteeing children's rights, targeting particularly those children in situations of psychosocial risk. While a certain amount of evidence exists regarding how family support is generally delivered in certain European countries, with a particular focus on parenting initiatives, this paper aims to take existing evidence one step further by providing an updated review focusing on two core components of the Council of Europe's Recommendation on Positive Parenting: families at psychosocial risk as the target population, and family education and support initiatives as the delivery format. The scope of the study was therefore broad, in both geographical and conceptual terms. An online survey was conducted with experts from 19 European countries to gather information regarding how they perceive family education and support initiatives for families at psychosocial risk. Both quantitative and qualitative data were analysed by computing frequencies/percentages and by following a thematic synthesis method, respectively. The results revealed both similarities and disparities as regards provider profiles, intervention characteristics, and quality standards. Practical implications are discussed, such as the need to diversify initiatives for at‐risk families in accordance with the tenets of progressive universalism, the ongoing need for an evidence‐based, pluralistic approach to programmes, and the skills and qualifications required in the family support workforce. This study constitutes a first step towards building a common family support framework at a European level, which would encompass family support and parenting policies aimed at families at psychosocial risk.Ministerio de Economía y Competitividad de España EDU2013‐41441‐

A Comparison of Front-Ends for Bitstream-Based ASR over IP

Automatic speech recognition (ASR) is called to play a relevant role in the provision of spoken interfaces for IP-based applications. However, as a consequence of the transit of the speech signal over these particular networks, ASR systems need to face two new challenges: the impoverishment of the speech quality due to the compression needed to fit the channel capacity and the inevitable occurrence of packet losses. In this framework, bitstream-based approaches that obtain the ASR feature vectors directly from the coded bitstream, avoiding the speech decoding process, have been proposed ([S.H. Choi, H.K. Kim, H.S. Lee, Speech recognition using quantized LSP parameters and their transformations in digital communications, Speech Commun. 30 (4) (2000) 223–233. A. Gallardo-Antolín, C. Pelàez-Moreno, F. Díaz-de-María, Recognizing GSM digital speech, IEEE Trans. Speech Audio Process., to appear. H.K. Kim, R.V. Cox, R.C. Rose, Performance improvement of a bitstream-based front-end for wireless speech recognition in adverse environments, IEEE Trans. Speech Audio Process. 10 (8) (2002) 591–604. C. Peláez-Moreno, A. Gallardo-Antolín, F. Díaz-de-María, Recognizing voice over IP networks: a robust front-end for speech recognition on the WWW, IEEE Trans. Multimedia 3(2) (2001) 209–218], among others) to improve the robustness of ASR systems. LSP (Line Spectral Pairs) are the preferred set of parameters for the description of the speech spectral envelope in most of the modern speech coders. Nevertheless, LSP have proved to be unsuitable for ASR, and they must be transformed into cepstrum-type parameters. In this paper we comparatively evaluate the robustness of the most significant LSP to cepstrum transformations in a simulated VoIP (voice over IP) environment which includes two of the most popular codecs used in that network (G.723.1 and G.729) and several network conditions. In particular, we compare ‘pseudocepstrum’ [H.K. Kim, S.H. Choi, H.S. Lee, On approximating Line Spectral Frequencies to LPC cepstral coefficients, IEEE Trans. Speech Audio Process. 8 (2) (2000) 195–199], an approximated but straightforward transformation of LSP into LP cepstral coefficients, with a more computationally demanding but exact one. Our results show that pseudocepstrum is preferable when network conditions are good or computational resources low, while the exact procedure is recommended when network conditions become more adverse.Publicad

Band-pass filtering of the time sequences of spectral parameters for robust wireless speech recognition

In this paper we address the problem of automatic speech recognition when wireless speech communication systems are involved. In this context, three main sources of distortion should be considered: acoustic environment, speech coding and transmission errors. Whilst the first one has already received a lot of attention, the last two deserve further investigation in our opinion. We have found out that band-pass filtering of the recognition features improves ASR performance when distortions due to these particular communication systems are present. Furthermore, we have evaluated two alternative configurations at different bit error rates (BER) typical of these channels: band-pass filtering the LP-MFCC parameters or a modification of the RASTA-PLP using a sharper low-pass section perform consistently better than LP-MFCC and RASTA-PLP, respectively.Publicad

Estudio anatómico y planimétrico de los aneurismas de aorta abdominal

El aneurisma de aorta abdominal es una patología cuya incidencia está en aumento. Su principal complicación es la ruptura, que puede ocasionar la muerte del paciente. Por ello, cuando alcanzan un determinado tamaño (5 cm.), el paciente debe recibir tratamiento quirúrgico. Actualmente el tratamiento endovascular se ha consolidado frente a la cirugía abierta convencional. Para llevar a cabo la implantación de endoprótesis es fundamental conocer la morfología del aneurisma que se va a tratar. Este estudio lleva a cabo un estudio morfológico y planimétrico de dichos aneurismas con el fin de optimizar el tratamiento protésico endovascular.OtroGrado en Medicin

Evaluación de las políticas de atracción de IED : el caso del sector eléctrico centroamericano

Las políticas de atracción de Inversión Extranjera Directa experimentaron un cambio significativo durante la década de los ochenta. Este cambio ha tenido como objetivo fundamental crear las condiciones más favorables posibles a la llegada de estas inversiones. Si la deslocalización de la producción industrial ya venía siendo un fenómeno significativo desde prácticamente el final de la Segunda Guerra Mundial, no ocurría lo mismo en el caso del sector servicios. Por ello, uno de los aspectos más novedosos de estas nuevas políticas de atracción ha sido la liberalización y privatización de estos sectores, hechos que han favorecido la expansión internacional de algunas empresas, particularmente europeas y estadounidenses. El objetivo de esta investigación es analizar los resultados que esto ha tenido para los países receptores de estas inversiones, particularmente países en desarrollo. Para estos últimos, dichas políticas se consideraban especialmente necesarias para contribuir a la recuperación económica tras la crisis de la deuda. ____________________________________________Policies to attract FDI have changed significantly during the 80’s. The primary objective of this change was developing in the countries the most favourable conditions to attract FDI. For this reason, one of the most innovative feature of these new policies is the liberalization and privatization of the services. This is especially important because while offshoring processes were present in industrial activities since the end of the Second World War, it was not the case of the services sector. Therefore, policies to attract FDI led to the international expansion of a few firms, particularly from America and Europe.The objective of this paper is to analyze the results of these policies in the countries receiving the FDI, especially in the case of developing countries, because FDI was considered to play an important role in their development strategy

Individual creativity performance and the quality of interpersonal relationships

[EN] Purpose: The purpose of this paper is to analyze how the exchanges that employees maintain with their immediate superior and with their work group influence the creativity that they manifest. Design/methodology/approach: A study was carried out among employees of a firm from the automotive sector. On the basis of previous works, the authors first built reliable multi‐item scales for each variable included in the model; then, a multiple regression analysis was conducted to ascertain the causal effect of those exchanges upon creativity. Findings: The findings reveal that high‐quality exchanges between the employee and their work group and, to a lesser extent, their immediate superior, have a significant positive influence on their creative behavior. Practical implications: All this underlines the importance of the composition of work groups for achieving the team environment necessary for creative production. Originality/value: This paper provides new evidence about a still unexplored topic, trying to bridge the existing gap in the literature about the influence of leadership and group behavior on creativitySIMinisterio de Ciencia e Innovació

Network position, export patterns and competitiveness: evidence from the European automotive industry

The organizational characteristics of production in the European automotive industry have favoured a high degree of fragmentation and productive mobility. This article analyses the differing national positions of automotive producing countries and their export patterns – particularly their export reorientation to extra-European Union markets following the collapse of regional demand in the European automotive industry. Based on the methodologies of Mahutga and Piana, our position analysis arrives at two main conclusions: (i) the countries best positioned in the European regional automotive production network are precisely those that have experienced a greater increase in extra-European Union exports, thus reducing their dependence on regional European demand; (ii) the increase in extra-European Union exports (mainly of final goods) is linked to increased regional fragmentation of production in the automotive industry. We conclude that the governance of this fragmentation process is a key determinant of extra-European Union export competitiveness

A Speech Recognizer based on Multiclass SVMs with HMM-Guided Segmentation

Automatic Speech Recognition (ASR) is essentially a problem of pattern classification, however, the time dimension of the speech signal has prevented to pose ASR as a simple static classification problem. Support Vector Machine (SVM) classifiers could provide an appropriate solution, since they are very well adapted to high-dimensional classification problems. Nevertheless, the use of SVMs for ASR is by no means straightforward, mainly because SVM classifiers require an input of fixed-dimension. In this paper we study the use of a HMM-based segmentation as a mean to get the fixed-dimension input vectors required by SVMs, in a problem of isolated-digit recognition. Different configurations for all the parameters involved have been tested. Also, we deal with the problem of multi-class classification (as SVMs are initially binary classifers), studying two of the most popular approaches: 1-vs-all and 1-vs-1

An Application of SVM to Lost Packets Reconstruction in Voice-Enabled Services

Voice over IP (VoIP) is becoming very popular due to the huge range of services that can be implemented by integrating different media (voice, audio, data, etc.). Besides, voice-enabled interfaces for those services are being very actively researched. Nevertheless the impoverishment of voice quality due to packet losses severely affects the speech recognizers supporting those interfaces ([8]). In this paper, we have compared the usual lost packets reconstruction method with an SVM-based one that outperforms previous results