Fuzzy Logic Control for Multiresolutive Adaptive PN Acquisition Scheme in Time-Varying Multipath Ionospheric Channel

Communication with remote places is a challenge often solved using satellites. However, when trying to reach Antarctic stations, this solution suffers from poor visibility range and high operational costs. In such scenarios, skywave ionospheric communication systems represent a good alternative to satellite communications. The Research Group in Electromagnetism and Communications (GRECO) is designing an HF system for long haul digital communication between the Antarctic Spanish Base in Livingston Island (62.6S, 60.4W) and Observatori de l’Ebre in Spain (40.8N,0.5E) (Vilella et al., 2008). The main interest of Observatori de l’Ebre is the transmission of the data collected from the sensors located at the base, including a geomagnetic sensor, a vertical incidence ionosonde, an oblique incidence ionosonde and a GNSS receiver. The geomagnetic sensor, the vertical incidence ionosonde and the GNSS receiver are commercial solutions from third parties. The oblique incidence ionosonde, used to sound the ionospheric channel between Antarctica and Spain, was developed by the GRECO in the framework of this project. During the last Antarctic campaign, exhaustive measurements of the HF channel characteristics were performed, which allowed us to determine parameters such as availability, SNR, delay and Doppler spread, etc. In addition to the scientific interest of this sounding, a further objective of the project is the establishment of a backup link for data transmission from the remote sensors in the Antarctica. In this scenario, ionospheric communications appear to be an interesting complementary alternative to geostationary satellite communications since the latter are expensive and not always available from high-latitudes. Research work in the field of fuzzy logics applied to the estimation of the above mentioned channel was first applied in (Alsina et al., 2005a) for serial search acquisition systems in AWGN channels, afterwards applied to the same channel but in the multiresolutive structure (Alsina et al., 2009a; Morán et al., 2001) in papers (Alsina et al., 2007b; 2009b) achieving good results. In this chapter the application of fuzzy logic control trained for Rayleigh fading channels (Proakis, 1995) with Direct-Sequence Spread-Spectrum (DS-SS) is presented, specifically suited for the ionospheric channel Antarctica-Spain. Stability and reliability of the reception, which are currently being designed, are key factors for the reception. It is important to note that the fuzzy control design presented in this chapter not only resolves the issue of improving the multiresolutive structure performance presented by (Morán et al., 2001), but also introduces a new option for the control design of many LMS adaptive structures used for PN code acquisition found in the literature. (El-Tarhuni & Sheikh, 1996) presented an LMS-based system to acquire a DS-SS system in Rayleigh channels; years after, (Han et al., 2006) improved the performance of the acquisition system designed by (El-Tarhuni & Sheikh, 1996). And also in other type of channels, LMS filters are used as an acquisition system, even in oceanic transmissions (Stojanovic & Freitag, 2003). Although the fuzzy control system presented in this chapter is compared to the stability control used in (Morán et al., 2001) it also can be used to improve all previous designs performance in terms of stability and robustness. Despite this generalization, the design of every control system should be done according to the requirements of the acquisition system and the specific channel characteristics

Adaptación del CTH-URL para la competición ALBAYZIN 2008

En esta comunicación describimos el sistema de síntesis de voz presentado a la competición Albayzin 2008. Es un sistema que sigue un esquema clásico de concatenación de unidades basado en corpus. Cabe destacar que los costes de selección se han ajustado mediante un método basado en algoritmos genéticos y que no se ha utilizado ningún sistema de predicción prosódica. Se construyeron dos sistemas preliminares que diferían en el algoritmo de generación de forma de onda escogiendo el que se presenta a la competición mediante un test perceptual.Peer ReviewedPostprint (published version

Processament avançat, febrer 2014

Recurs d'aprenentatge de la Universitat Oberta de Catalunya.Recurso de aprendizaje de la "Universitat Oberta de Catalunya".Learning material of the "Universitat Oberta de Catalunya"

Proceso avanzado, febrero 2014

Recurs d'aprenentatge de la Universitat Oberta de Catalunya.Recurso de aprendizaje de la "Universitat Oberta de Catalunya".Learning material of the "Universitat Oberta de Catalunya"

La Conversión de Texto en Habla Multidominio: principios y portabilidad

La conversión de texto en habla (CTH) multidominio per-sigue conseguir una calidad sintética cercana a la de lossistemas de CTH diseñados para un determinado ámbi-to o aplicación, aumentando su flexibilidad al considerardistintos dominios (estilos de locución, emociones, temá-ticas, etc.) para la síntesis. En este trabajo, se presentanlasmotivaciones de esta estrategia desarrollada como evolu-ción paralela a los sistemas orales multidominio, junto adistintas reflexiones sobre su flexibilidad y portabilidadpara el diseño de nuevos sistemas de CTH a partir de lasconclusiones obtenidas hasta el momento

Description of Anomalous Noise Events for Reliable Dynamic Traffic Noise Mapping in Real-Life Urban and Suburban Soundscapes

Traffic noise is one of the main pollutants in urban and suburban areas. European authorities have driven several initiatives to study, prevent and reduce the effects of exposure of population to traffic. Recent technological advances have allowed the dynamic computation of noise levels by means of Wireless Acoustic Sensor Networks (WASN) such as that developed within the European LIFE DYNAMAP project. Those WASN should be capable of detecting and discarding non-desired sound sources from road traffic noise, denoted as anomalous noise events (ANE), in order to generate reliable noise level maps. Due to the local, occasional and diverse nature of ANE, some works have opted to artificially build ANE databases at the cost of misrepresentation. This work presents the production and analysis of a real-life environmental audio database in two urban and suburban areas specifically conceived for anomalous noise events’ collection. A total of 9 h 8 min of labelled audio data is obtained differentiating among road traffic noise, background city noise and ANE. After delimiting their boundaries manually, the acoustic salience of the ANE samples is automatically computed as a contextual signal-to-noise ratio (SNR). The analysis of the real-life environmental database shows high diversity of ANEs in terms of occurrences, durations and SNRs, as well as confirming both the expected differences between the urban and suburban soundscapes in terms of occurrences and SNRs, and the rare nature of AN

Processament avançat, febrer 2014

Recurs d'aprenentatge de la Universitat Oberta de Catalunya.Recurso de aprendizaje de la "Universitat Oberta de Catalunya".Learning material of the "Universitat Oberta de Catalunya"

Proceso avanzado, febrero 2014

Recurs d'aprenentatge de la Universitat Oberta de Catalunya.Recurso de aprendizaje de la "Universitat Oberta de Catalunya".Learning material of the "Universitat Oberta de Catalunya"

Análisis y Síntesis Audiovisual para Interfaces Multimodales Ordenador-Persona

Las técnicas multimodales de procesamiento de señal están llamadas a jugar un papel preponderante en la implementación de interfaces que faciliten la interacción natural entre los ordenadores y los humanos. En particular, el desarrollo de interfaces eficientes que emulen la comunicación entre personas requiere el uso de técnicas capaces de procesar conjuntamente los modos visual y auditivo. Este trabajo introduce el uso de herramientas de análisis audiovisual basadas en el análisis en componentes principales y en descomposiciones que utilizan restricciones de no negatividad sobre secuencias faciales de vídeo con voz. Además, se estudia y compara la aplicabilidad de las bases audiovisuales obtenidas mediante estas técnicas a lo largo de diversos experimentos en los que se evalúa la calidad de la síntesis audiovisual de forma objetiva y subjetiv