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

Gas-liquid interfacial area in oxygen absorption into oil-in-water emulsions

Present work includes an exhaustive study about gas-liquid interfacial area between gas phase and liquid heterogeneous medium generated in an airlift bioreactor. The model system studied is composed by water, methyl ricinoleate and Tween 80, since it is the base of the medium used for the production of γ-decalactone through the biotransformation of ricinoleic acid, by the yeast Yarrowia lipolytica. Experimental results allow describing the hydrodynamic behavior of the gas phase into the biphasic medium. In the oil-in-water system used, a decrease of the gas-liquid interfacial area with the oil concentration increase was found, due to the redistribution of surfactant between interface and bulk phases

Permeabilidad de gases en membranas de zeolita ZSM-5

El trabajo incluido en el presente articulo tiene como objetivo analizar la influencia de la deposición de zeolita ZSM-5 en un tubo de alumina sobre la velocidad de transferencia de materia de distintos gases con el fin de analizar la capacidad de separación. Se ha evaluado la influencia de la presencia de zeolita, así como del caudal de gas alimentado y la temperatura a la que se desarrolla el proceso deseparación

Gases Separation by ZSM-5 based Membranes

AbstractPresent work analyses the effect produced by the presence of ZSM-5 zeolite in an alumina tube upon the permeation rate of different gases (nitrogen, oxygen, carbon dioxide and normal-butane). A comparison between experimental data of permeation through the membrane with and without ZSM-5 zeolite was performed with an increase in the resistance to transport more evident for n-butane. Also the influence of temperature upon permeation has been analyzed

Homogenization of Variational Inequalities for the p-Laplace Operator in Perforated Media Along Manifolds

We address homogenization problems of variational inequalities for the p-Laplace operator in a domain of Rn (n ? 3, p ? [2, n)) periodically perforated by balls of radius O(??) where ? > 1 and ? is the size of the period. The perforations are distributed along a (n ? 1)-dimensional manifold ? , and we impose constraints for solutions and their fluxes (associated with the p-Laplacian) on the boundary of the perforations. These constraints imply that the solution is positive and that the flux is bounded from above by a negative, nonlinear monotonic function of the solution multiplied by a parameter ? ?? , ? ? R and ? is a small parameter that we shall make to go to zero. We analyze different relations between the parameters p, n, ?, ? and ?, and obtain homogenized problems which are completely new in the literature even for the case p = 2.This work has been partially supported by the Spanish grant MINECO:MTM2013-44883-P

Cartografía visual : creación de narrativas visuales colaborativas a partir de conexiones acerca del barrio Nou Llevant-Soledat Sud de Palma

Este estudio busca concienciar al profesorado, que desarrolla su labor docente en un contexto social y cultural desfavorecido, sobre las posibilidades que ofrece la construcción de un mapa visual de su entorno. A fin de establecer conexiones de una manera expresiva y colaborativa, se llevó a cabo un taller en una escuela de primaria con alumnado de quinto curso perteneciente al barrio Nou Llevant-Soledat Sud de Palma (Islas Baleares, España). A través del mapeo narrativo como técnica analítica, los y las escolares construyeron un nuevo lenguaje, una red (su red) analógica de información. La creación de mapas ha reforzado el mensaje de intersección y fomentado nuevos comportamientos. La aproximación de diferentes universos a través de dibujos llevados a cabo por el alumnado nos ha permitido la creación de narrativas y consecuentes mapas mentales. Los resultados informan sobre la importancia que tiene la representación cartografía como herramienta de aprendizaje y sensibilización educativa. Asimismo, permite un proceso creativo en un intento de aliviar la carga cognitiva de la realidad del barrio y hace de la información resultante un “filtrado” más amable.info:eu-repo/semantics/publishedVersio

Consideraciones para una adecuada descripción de perfiles de suelos

The existing soil profile description systems were done systematicaly based on land capability, keeping out genetic criteria, for instance. So that, the application of these systems for soil genesis studies will be problematic. In the other hand, the terminology to use is showed as a complex one and could drive us to make mistakes when we can see the same adjetive califing different things on different systems.Los sistemas para descripción de perfiles de suelos existentes, se han hecho sistemáticamente, en base a capacidades de uso de la tierra, dejando aparte criterios genéticos, por ejemplo. Así, la aplicación de estos sistemas a estudios de génesis de suelos resulta problemática. Por otra parte, la terminología a usar puede resultar compleja y llevar a errores, cuando vemos que el mismo adjetivo califica cosas distintas en diferentes sistemas

Niche Partitioning of Feather Mites within a Seabird Host, Calonectris borealis

According to classic niche theory, species can coexist in heterogeneous environments by reducing interspecific competition via niche partitioning, e.g. trophic or spatial partitioning. However, support for the role of competition on niche partitioning remains controversial. Here, we tested for spatial and trophic partitioning in feather mites, a diverse and abundant group of arthropods. We focused on the two dominant mite species, Microspalax brevipes and Zachvatkinia ovata, inhabiting flight feathers of the Cory's shearwater, Calonectris borealis. We performed mite counts across and within primary and tail feathers on free-living shearwaters breeding on an oceanic island (Gran Canaria, Canary Islands). We then investigated trophic relationships between the two mite species and the host using stable isotope analyses of carbon and nitrogen on mite tissues and potential host food sources. The distribution of the two mite species showed clear spatial segregation among feathers; M. brevipes showed high preference for the central wing primary feathers, whereas Z. ovata was restricted to the two outermost primaries. Morphological differences between M. brevipes and Z. ovata support an adaptive basis for the spatial segregation of the two mite species. However, the two mites overlap in some central primaries and statistical modeling showed that Z. ovata tends to outcompete M. brevipes. Isotopic analyses indicated similar isotopic values for the two mite species and a strong correlation in carbon signatures between mites inhabiting the same individual host suggesting that diet is mainly based on shared host-associated resources. Among the four candidate tissues examined (blood, feather remains, skin remains and preen gland oil), we conclude that the diet is most likely dominated by preen gland oil, while the contribution of exogenous material to mite diets is less marked. Our results indicate that ongoing competition for space and resources plays a central role in structuring feather mite communities. They also illustrate that symbiotic infracommunities are excellent model systems to study trophic ecology, and can improve our understanding of mechanisms of niche differentiation and species coexistence

Monolithic stirrer reactors for the sustainable production of dihydroxybenzenes over 3D printed Fe/γ-Al2O3 monoliths: kinetic modeling and CFD simulation

The aim of this work is to evaluate the performance of the stirring 3D Fe/Al2O3 monolithic reactor in batch operation applied to the liquid-phase hydroxylation of phenol by hydrogen peroxide (H2O2 ). An experimental and numerical investigation was carried out at the following operating conditions: CPHENOL,0 = 0.33 M, CH2O2,0 = 0.33 M, T = 75–95◦C, P = 1 atm, ω = 200–500 rpm and WCAT ~ 1.1 g. The kinetic model described the consumption of the H2O2 by a zero-order power-law equation, while the phenol hydroxylation and catechol and hydroquinone production by Eley–Rideal model; the rate determining step was the reaction between the adsorbed H2O2, phenol in solution with two active sites involved. The 3D CFD model, coupling the conservation of mass, momentum and species together with the reaction kinetic equations, was experimentally validated. It demonstrated a laminar flow characterized by the presence of an annular zone located inside and surrounding the monoliths (u = 40–80 mm s−1 ) and a central vortex with very low velocities (u = 3.5–8 mm s−1 ). The simulation study showed the increasing phenol selectivity to dihydroxybenzenes by the reaction temperature, while the initial H2O2 concentration mainly affects the phenol conversio