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

European land-use at 6000 BP: from on-site data to the large-scale view

No abstract available

A wearable wireless sensor network for indoor smart environment monitoring in safety applications

This paper presents the implementation of a wearable wireless sensor network aimed at monitoring harmful gases in industrial environments. The proposed solution is based on a customized wearable sensor node using a low-power low-rate wireless personal area network (LR-WPAN) communications protocol, which as a first approach measures CO2 concentration, and employs different low power strategies for appropriate energy handling which is essential to achieving long battery life. These wearables nodes are connected to a deployed static network and a web-based application allows data storage, remote control and monitoring of the complete network. Therefore, a complete and versatile remote web application with a locally implemented decision-making system is accomplished, which allows early detection of hazardous situations for exposed workers

Comprender y construir la mediación intercultural = Understanding and developing the intercultural mediation

Ante la relativamente nueva introducción de la denominada mediación intercultural en el escenario del trabajo con la inmigración extranjera en España, se han multiplicado los debates y posiciones sobre la figura profesional que ha de ejercer tal actividad de mediación intercultural. Para contribuir a dichos debates aportamos el resumen de los resultados de un estudio que pretende delimitar el perfil del llamado "mediador o mediadora intercultural". El estudio ha consistido básicamente en hacer un recorrido por tres fuentes de información fundamentales: la formación que se ha proporcionado a mediadores y mediadoras interculturales en diferentes contextos europeos, las características y competencias que se les han atribuido y, por último, las funciones que se dice debe cumplir la mediación. Estos tres ámbitos de información deben dar respuesta adecuada al perfil del mediador o mediadora intercultural, destacando en especial su delimitación profesional, las proximidades y relaciones con otras profesiones y, en especial, el tipo de formación necesario para la capacitación profesional.In the face of the relatively new introduction of the named intercultural mediation in the context of work with foreign immigration in Spain, debates and positions on the professional figure that intercultural mediation has to be wielded have multiplied. In order to contribute to such debates, we provide the summary of the results of a study that aims to delimit the profile of the so called ‘’intercultural mediator’’. The study basically consisted of taking a tour for three fundamental sources of information: The training provided to intercultural mediators in different European contexts, the characteristics and competences attributed to them, and lastly, the functions that are said to be fulfilled by the mediator. These three aspects of information must give an adequate answer to the ’intercultural mediator’ profile, highlighting his professional delimitations, the proximities and relations with other professions, and especially, the type of training required for the vocational training

Procesos deposicionales y antrópicos en el registro holoceno de la Cova de Can Sadurní (Begues, Barcelona, España): aportaciones microestratigráficas

El estudio geoarqueológico y microestratigráfico de la secuencia de la Cova de Can Sadurní (Begues, Barcelona) ofrece una variabilidad de procesos deposicionales de tipo detrítico y antrópico que en determinadas etapas se alternan y repercuten en los procesos diagenéticos localizados. La secuencia cultural del yacimiento va desde el Epipaleolítico hasta época Romana bajo imperial con algunas interrupciones cronoculturales. Durante el Epipaleolítico y Mesolítico los aportes solifluidales son los responsables de la sedimentación. A partir del Neolítico, movimientos de masa y procesos coluvionales son los dominantes. Se distinguen flujos densos principalmente durante el Neolítico antiguo cardial y postcardial inicial; también se localizan pero con menor extensión durante el Neolítico medio postcardial, Neolítico final/Calcolítico y en el Bronce inicial. Los aportes coluvionales no laminados aparecen en el resto de la secuencia. Estos episodios se alternan con fases de estabilidad en el medio en el que la tasa de sedimentación detrítica es menor o casi inexistente y es reemplazada por los aportes procedentes de las actividades de estabulación localizados in situ durante el Neolítico epicardial y postcardial inicial; aunque ya se constaten evidencias desde el Neolítico antiguo cardial. Asociados a estos contextos, los procesos hidromórficos se acentúan dando lugar a la formación de vivianita, fosfato de hierro, propia de lugares reductores con un gran contenido orgánico

Metamorfosis en Augusta Treverorum

Trier Stadtbibliothek owns five unpublished Ovidian fragments, one from Amores and four from Metamorphoses. This paper offers a first-time collation of the latter.No disponible

Improvement of Impact Toughness and Abrasion Resistance of a 3C-25Cr-0.5Mo Alloy Using a Design of Experiment Statistical Technique: Microstructural Correlations after Heat Treatments

[Abstract] Hypoeutectic high chromium white cast irons are commonly used in the mining and cement industries, where high resistance to abrasive wear is demanded. Through the application of a Design of Experiment technique (DoE), different factors related to thermal industrial treatments are analysed with regard to resistance to abrasive wear and impact response. Abrasion tests were carried out in accordance with the ASTM G065-16 standard. The provisional results show that to increase wear resistance, high destabilisation temperatures (1050 ◦C) followed by slow cooling to room temperature (RT) and subsequent tempering at 400 ◦C are most favourable. This is because these conditions are favourable to maintaining a certain tetragonality of the martensite after tempering and also, because of the presence of a high density of mixed carbides M7C3, through a secondary precipitation during cooling. Oil quenching and a high tempering temperature (550 ◦C) with long dwell times of 6 h were found to increase impact toughness. These conditions favour a lack of retained austenite. The presence of retained austenite was found unfavourable for both wear resistance and toughness, whereas tempering at 400 ◦C has been shown to be insufficient to transform martensite on tempering, which in turn seemed to increase the hardness of the matrix constituent

Evaluation of Hardness, Sliding Wear and Strength of a Hypoeutectic White Iron with 25%Cr after Heat Treatments

[Abstract] Hypoeutectic white cast irons with a high chrome content are commonly used in the industrial mining sector where there is a demand for both high resistance to adhesive wear and an acceptable toughness for the absorption of impacts and falls of diverse materials. Through the application of a design of experiment (DoE) technique, factors related to thermal treatment are analyzed with respect to resistance to sliding wear, maximum rupture stress and toughness. The results show that, in order to increase resistance to adhesive wear, it is convenient to use destabilization temperatures of 1050 ◦C and tempering of two hours at 400 ◦C. This foments a very hard martensite and a high proportion of highly alloyed retained austenite, which, with low tempering, achieves a precipitation of carbides from this austenite with hardly any loss of hardness of the martensite. In order to increase the energy which this material is capable of absorbing until breakage, furnace cooling set at 150 ◦C followed by tempering at 550 ◦C would be favorable. Slower cooling implies a greater quantity of conditioned retained austenite, so that, following this, it may be transformed into lower bainite with a high density of finely dispersed precipitated carbides. Furthermore, this tempering also allows the transformation of martensite into ferrite with finely dispersed carbides

Middle Neolithic farming of open-air sites in SE France: new insights from archaeobotanical investigations of three wells found at Les Bagnoles (L'Isle-sur-la-Sorgue, Dépt. Vaucluse, France)

Previous reviews of Middle Neolithic agricultural practice (4400–3500 cal bc) in southern France have highlighted a change in crop assemblages after 4000 cal bc, with a reduction of naked wheat and an increase of emmer and partly of einkorn. The recent investigation of three wells from the site of Les Bagnoles (4250–3800 cal bc) in the periphery of the southern Rhône valley yielded an unprecedented amount of waterlogged uncharred and charred plant macro remains that offer new insights into crop diversity and its changes over time. The results from the wells at Les Bagnoles were compared with other dated sunken features from open-air sites (in contrast to caves and rock shelters), with the aim of identifying patterns sug-gesting changes in the crop spectra between the early (MN1) and late (MN2) Middle Neolithic phases from taphonomically comparable contexts. The results from Les Bagnoles demonstrate that oil crops and pulses are underrepresented in dry sites and that they were a significant part of Middle Neolithic agriculture. They also indicate an increase in the representation of einkorn (instead of emmer) during MN2 that is also visible in other open-air sites. The comparison of the archaeobotani-cal results with silo storage capacity values as a proxy for average production capacity per household leads us to propose a possible drop in naked wheat productivity and opens new questions in factors affecting crop choice at the beginning of the 4th millennium cal bc