Linear and nonlinear room compensation of audio rendering systems

[EN] Common audio systems are designed with the intent of creating real and immersive scenarios that allow the user to experience a particular acoustic sensation that does not depend on the room he is perceiving the sound. However, acoustic devices and multichannel rendering systems working inside a room, can impair the global audio effect and thus the 3D spatial sound. In order to preserve the spatial sound characteristics of multichannel rendering techniques, adaptive filtering schemes are presented in this dissertation to compensate these electroacoustic effects and to achieve the immersive sensation of the desired acoustic system. Adaptive filtering offers a solution to the room equalization problem that is doubly interesting. First of all, it iteratively solves the room inversion problem, which can become computationally complex to obtain when direct methods are used. Secondly, the use of adaptive filters allows to follow the time-varying room conditions. In this regard, adaptive equalization (AE) filters try to cancel the echoes due to the room effects. In this work, we consider this problem and propose effective and robust linear schemes to solve this equalization problem by using adaptive filters. To do this, different adaptive filtering schemes are introduced in the AE context. These filtering schemes are based on three strategies previously introduced in the literature: the convex combination of filters, the biasing of the filter weights and the block-based filtering. More specifically, and motivated by the sparse nature of the acoustic impulse response and its corresponding optimal inverse filter, we introduce different adaptive equalization algorithms. In addition, since audio immersive systems usually require the use of multiple transducers, the multichannel adaptive equalization problem should be also taken into account when new single-channel approaches are presented, in the sense that they can be straightforwardly extended to the multichannel case. On the other hand, when dealing with audio devices, consideration must be given to the nonlinearities of the system in order to properly equalize the electroacoustic system. For that purpose, we propose a novel nonlinear filtered-x approach to compensate both room reverberation and nonlinear distortion with memory caused by the amplifier and loudspeaker devices. Finally, it is important to validate the algorithms proposed in a real-time implementation. Thus, some initial research results demonstrate that an adaptive equalizer can be used to compensate room distortions.[ES] Los sistemas de audio actuales están diseñados con la idea de crear escenarios reales e inmersivos que permitan al usuario experimentar determinadas sensaciones acústicas que no dependan de la sala o situación donde se esté percibiendo el sonido. Sin embargo, los dispositivos acústicos y los sistemas multicanal funcionando dentro de salas, pueden perjudicar el efecto global sonoro y de esta forma, el sonido espacial 3D. Para poder preservar las características espaciales sonoras de los sistemas de reproducción multicanal, en esta tesis se presentan los esquemas de filtrado adaptativo para compensar dichos efectos electroacústicos y conseguir la sensación inmersiva del sistema sonoro deseado. El filtrado adaptativo ofrece una solución al problema de salas que es interesante por dos motivos. Por un lado, resuelve de forma iterativa el problema de inversión de salas, que puede llegar a ser computacionalmente costoso para los métodos de inversión directos existentes. Por otro lado, el uso de filtros adaptativos permite seguir las variaciones cambiantes de los efectos de la sala de escucha. A este respecto, los filtros de ecualización adaptativa (AE) intentan cancelar los ecos introducidos por la sala de escucha. En esta tesis se considera este problema y se proponen esquemas lineales efectivos y robustos para resolver el problema de ecualización mediante filtros adaptativos. Para conseguirlo, se introducen diferentes esquemas de filtrado adaptativo para AE. Estos esquemas de filtrado se basan en tres estrategias ya usadas en la literatura: la combinación convexa de filtros, el sesgado de los coeficientes del filtro y el filtrado basado en bloques. Más especificamente y motivado por la naturaleza dispersiva de las respuestas al impulso acústicas y de sus correspondientes filtros inversos óptimos, se presentan diversos algoritmos adaptativos de ecualización específicos. Además, ya que los sistemas de audio inmersivos requieren usar normalmente múltiples trasductores, se debe considerar también el problema de ecualización multicanal adaptativa cuando se diseñan nuevas estrategias de filtrado adaptativo para sistemas monocanal, ya que éstas deben ser fácilmente extrapolables al caso multicanal. Por otro lado, cuando se utilizan dispositivos acústicos, se debe considerar la existencia de no linearidades en el sistema elactroacústico, para poder ecualizarlo correctamente. Por este motivo, se propone un nuevo modelo no lineal de filtrado-x que compense a la vez la reverberación introducida por la sala y la distorsión no lineal con memoria provocada por el amplificador y el altavoz. Por último, es importante validar los algoritmos propuestos mediante implementaciones en tiempo real, para asegurarnos que pueden realizarse. Para ello, se presentan algunos resultados experimentales iniciales que muestran la idoneidad de la ecualización adaptativa en problemas de compensación de salas.[CA] Els sistemes d'àudio actuals es dissenyen amb l'objectiu de crear ambients reals i immersius que permeten a l'usuari experimentar una sensació acústica particular que no depèn de la sala on està percebent el so. No obstant això, els dispositius acústics i els sistemes de renderització multicanal treballant dins d'una sala poden arribar a modificar l'efecte global de l'àudio i per tant, l'efecte 3D del so a l'espai. Amb l'objectiu de conservar les característiques espacials del so obtingut amb tècniques de renderització multicanal, aquesta tesi doctoral presenta esquemes de filtrat adaptatiu per a compensar aquests efectes electroacústics i aconseguir una sensació immersiva del sistema acústic desitjat. El filtrat adaptatiu presenta una solució al problema d'equalització de sales que es interessant baix dos punts de vista. Per una banda, el filtrat adaptatiu resol de forma iterativa el problema inversió de sales, que pot arribar a ser molt complexe computacionalment quan s'utilitzen mètodes directes. Per altra banda, l'ús de filtres adaptatius permet fer un seguiment de les condicions canviants de la sala amb el temps. Més concretament, els filtres d'equalització adaptatius (EA) intenten cancel·lar els ecos produïts per la sala. A aquesta tesi, considerem aquest problema i proposem esquemes lineals efectius i robustos per a resoldre aquest problema d'equalització mitjançant filtres adaptatius. Per aconseguir-ho, diferent esquemes de filtrat adaptatiu es presenten dins del context del problema d'EA. Aquests esquemes de filtrat es basen en tres estratègies ja presentades a l'estat de l'art: la combinació convexa de filtres, el sesgat dels pesos del filtre i el filtrat basat en blocs. Més concretament, i motivat per la naturalesa dispersa de la resposta a l'impuls acústica i el corresponent filtre òptim invers, presentem diferents algorismes d'equalització adaptativa. A més a més, com que els sistemes d'àudio immersiu normalment requereixen l'ús de múltiples transductors, cal considerar també el problema d'equalització adaptativa multicanal quan es presenten noves solucions de canal simple, ja que aquestes s'han de poder estendre fàcilment al cas multicanal. Un altre aspecte a considerar quan es treballa amb dispositius d'àudio és el de les no linealitats del sistema a l'hora d'equalitzar correctament el sistema electroacústic. Amb aquest objectiu, a aquesta tesi es proposa una nova tècnica basada en filtrat-x no lineal, per a compensar tant la reverberació de la sala com la distorsió no lineal amb memòria introduïda per l'amplificador i els altaveus. Per últim, és important validar la implementació en temps real dels algorismes proposats. Amb aquest objectiu, alguns resultats inicials demostren la idoneïtat de l'equalització adaptativa en problemes de compensació de sales.Fuster Criado, L. (2015). Linear and nonlinear room compensation of audio rendering systems [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/5945

Barriers to Learning and Participation in School of Students with Dyslexia: Family Voices

Alcanzar una educación de calidad, nos remite a la educación que debe ser inclusiva y equitativa, poniendo énfasis en el valor de las diferencias para mejorar la enseñanza y las experiencias de aprendizaje. Pero, todavía son muchos los que sufren procesos de exclusión en la escuela; los que tienen un diagnóstico de dislexia conforman un grupo dañado por prácticas y culturas de centro escasamente acogedoras. El presente estudio se orienta a analizar las barreras que frenan su aprendizaje y las secuelas que producen. Desde un enfoque metodológico de corte biográfico-narrativo, las voces de familias, a través de la entrevista, revelan que son múltiples los obstáculos que, más allá de problematizar el progreso de sus hijos e hijas, perjudican su autoconcepto y autoestima. Los resultados muestran como principales barreras aquellas que están relacionadas con la falta de comunicación eficiente escuela-familia, metodologías de aula que por su naturaleza magnifican las dificultades en la lectura y la escritura repercutiendo en el aprendizaje, y el impacto emocional producido por la ausencia de respuestas a las necesidades del alumnado con dislexia. Visibilizar estas barreras es un compromiso con el derecho a una educación de calidad para y con todos en la educación obligatoriaAchieving quality education refers us to education that must be inclusive and equitable, emphasizing the value of differences in order to improve teaching and learning experiences. But, there are still many who suffer processes of exclusion in school; those who have dyslexia make up a group damaged by poorly welcoming practices and center cultures. The present study is oriented to analyze the barriers that hinder their learning and the sequels that produce. From a biographicalnarrative methodological approach, the voices of families, through the interview, reveal that there are multiple obstacles that, beyond problematizing the progress of their sons and daughters, harm their self-concept and self-esteem. The results show as main barriers those related to the lack of efficient school-family communication, classroom methodologies that by their nature magnify the difficulties in reading and writing impacting on learning, and the emotional impact produced by the absence of responses to the needs of students with dyslexia. Making these barriers visible is a commitment to the right to quality education for and with all in compulsory educatio

Editorial

Fuster-López, L.; Murray, A.; Jiménez Garnica, R. (2021). Editorial. SN Applied Sciences (Online). 3(9):1-3. https://doi.org/10.1007/s42452-021-04772-5133

UV-Vis Luminescence imaging techniques/ Técnicas de imagen de luminiscencia UV-Vis

Ever since its first introduction in the field of conservation, the role of UV-VIS luminescence/fluores-cence (UVL and UVf, respectively) imaging has been expanding.The unique and significant contribution of this technique for investigation of cultural heritage has led to the development of new methodol-ogies and applications. Each chapter in this volume can be read independently. While this means that some repetition may occur between the individual chapters, in particular regarding the explanation of terminology and methodology, such overlap provides interesting op-portunities for cross-comparison of both terminol-ogy and methodology. In addition, it highlights similarities and differences between different situations in the practical applicationFuster López, L.; Stols-Witlox, M.; Picollo, M. (2020). UV-Vis Luminescence imaging techniques/ Técnicas de imagen de luminiscencia UV-Vis. Editorial Universitat Politècnica de València. http://hdl.handle.net/10251/138517EDITORIA

El perfil del psicopedagogo

Vuitenes Jornades de Foment de la Investigació de la FCHS (Any 2002-2003

A simplified algorithm for inverting higher order diffusion tensors

In Riemannian geometry, a distance function is determined by an inner product on the tangent space. In Riemann-Finsler geometry, this distance function can be determined by a norm. This gives more freedom on the form of the so-called indicatrix or the set of unit vectors. This has some interesting applications, e.g., in medical image analysis, especially in diffusion weighted imaging (DWI). An important application of DWI is in the inference of the local architecture of the tissue, typically consisting of thin elongated structures, such as axons or muscle fibers, by measuring the constrained diffusion of water within the tissue. From high angular resolution diffusion imaging (HARDI) data, one can estimate the diffusion orientation distribution function (dODF), which indicates the relative diffusivity in all directions and can be represented by a spherical polynomial. We express this dODF as an equivalent spherical monomial (higher order tensor) to directly generalize the (second order) diffusion tensor approach. To enable efficient computation of Riemann-Finslerian quantities on diffusion weighted (DW)-images, such as the metric/norm tensor, we present a simple and efficient algorithm to invert even order spherical monomials, which extends the familiar inversion of diffusion tensors, i.e., symmetric matrices.</p

Adaptive Filtered-x Algorithms for Room Equalization Based on Block-Based Combination Schemes

(c) 2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.[EN] Room equalization has become essential for sound reproduction systems to provide the listener with the desired acoustical sensation. Recently, adaptive filters have been proposed as an effective tool in the core of these systems. In this context, this paper introduces different novel schemes based on the combination of adaptive filters idea: a versatile and flexible approach that permits obtaining adaptive schemes combining the capabilities of several independent adaptive filters. In this way, we have investigated the advantages of a scheme called combination of block-based adaptive filters which allows a blockwise combination splitting the adaptive filters into nonoverlapping blocks. This idea was previously applied to the plant identification problem, but has to be properly modified to obtain a suitable behavior in the equalization application. Moreover, we propose a scheme with the aim of further improving the equalization performance using the a priori knowledge of the energy distribution of the optimal inverse filter, where the block filters are chosen to fit with the coefficients energy distribution. Furthermore, the biased block-based filter is also introduced as a particular case of the combination scheme, especially suited for low signal-to-noise ratios (SNRs) or sparse scenarios. Although the combined schemes can be employed with any kind of adaptive filter, we employ the filtered-x improved proportionate normalized least mean square algorithm as basis of the proposed algorithms, allowing to introduce a novel combination scheme based on partitioned block schemes where different blocks of the adaptive filter use different parameter settings. Several experiments are included to evaluate the proposed algorithms in terms of convergence speed and steady-state behavior for different degrees of sparseness and SNRs.The work of L. A. Azpicueta-Ruiz was supported in part by the Comtmidad de Madrid through CASI-CAM-CM under Grant S2013/ICE-2845, in part by the Spanish Ministry of Economy and Competitiveness through DAMA under Grant TIN2015-70308-REDT, and Grant TEC2014-52289-R, and in part by the European Union. The work of L. Fuster, M. Ferrer, and M. de Diego was supported in part by EU together with the Spanish Government under Grant TEC2015-67387-C4-1-R (MINECO/FEDER), and in part by the Cieneralitat Valenciana under Grant PROMETEOII/2014/003. The associate editor coordinating the review of this manuscript and approving it for publication was Prof. Simon Dodo.Fuster Criado, L.; Diego Antón, MD.; Azpicueta-Ruiz, LA.; Ferrer Contreras, M. (2016). Adaptive Filtered-x Algorithms for Room Equalization Based on Block-Based Combination Schemes. IEEE/ACM Transactions on Audio, Speech and Language Processing. 24(10):1732-1745. https://doi.org/10.1109/TASLP.2016.2583065S17321745241

Study of the chemical composition and the mechanical behaviour of 20th century commercial artists' oil paints containing manganese-based pigments

[EN] The present study deals with 20th century manufactured artists' oil paints containing raw and burnt umber pigments, this is, natural earth pigments resulting from the combination of iron and manganese oxides. Manganese, in particular, is known to be a primary drier and to have a siccative effect on oil paint films. This research aims to show the diversity of formulations behind apparently same commercial names as well as to understand how the content of manganese, the presence of modern lipidic media and the hydrolysis mechanisms can promote significant differences in the expected mechanical properties of oil paint films, thus conditioning their long-term performance. Several manufactured artists' oil paint films containing manganese were selected. Dried films from raw and burnt umber oil paints by Winsor & (UK), Grumbacher (R) (USA), Gamblin (R) (USA) and Speedball (R) (USA) were studied and information about their chemical composition and mechanical behaviour is here presented. In addition-to the identification and the study of the inorganic and organic components present in each formulation through LM, SEM-EDX, FTIR-ATR, XRD, GC-MS analysis, tensile tests were run and stress strain curves were obtained. Together with evident hue differences, the obtained results showed significant differences in the chemical composition and the mechanical behaviour of the oil paint films. (C) 2015 Elsevier B.V. All rights reserved.The authors are deeply indebted to Dr. M.F. Mecklenburg (Museum Conservation Institute-Smithsonian Institution, USA) for providing the samples tested in this study and for the equipment donated. Gamblin Artists Colors and Kremer Pigmente GmbH & Co. KG are equally acknowledged for assisting with technical information regarding the materials tested. The authors also want to thank M. Planes and Dr. Moya (Microscopy Service, UPV) as well as Dra. Mestre (XRD Service at S.C.S.I.E, Universidad de Valencia-UV) for their technical assistance. This research was also possible thanks to the financial support from Ca' Foscari University of Venice (IRIDE departmental fund) and UPV Programa de Incentivo a la Investigacion (PAID-UPV-06-10-2429).Fuster-López, L.; Izzo, F.; Piovesan, M.; Yusa Marco, DJ.; Sperni, L.; Zendri, E. (2016). Study of the chemical composition and the mechanical behaviour of 20th century commercial artists' oil paints containing manganese-based pigments. Microchemical Journal. 124:962-973. https://doi.org/10.1016/j.microc.2015.08.02396297312

The Narrative Decorative Surfaces at the Spanish Colonial Mission Church of Santa María de Cuevas in Nueva Vizcaya: Where Religion, Art & Science Meet

[EN] This paper presents the conservation research project that has being carried out in the last 10 years to preserve the building and the artworks of Santa Maria Cuevas, a Spanish colonial mission founded by the Jesuits missionaries in 1678 at Nueva Vizcaya (Mexico). Located at the Mexican state of Chihuahua, this church continues to be the center of the cultural and religious traditions f its community. Of Particular interest is the complex polychrome technique and wooden ceiling structure. The original paintings narrate the Assumption of the Virgin Mary. In this paper, special attention is given to the studies that are currently being undertaken to interpret the narrative iconography that the Sicilian missionary Luis Mancuso together with the painter Domingo Guerra designed and painted in 1700.Muñoz-Alcocer, KM.; Fuster-López, L.; Ruiz Checa, JR.; Vázquez De Ágredos Pascual, ML. (2017). The Narrative Decorative Surfaces at the Spanish Colonial Mission Church of Santa María de Cuevas in Nueva Vizcaya: Where Religion, Art & Science Meet. European Journal of Science and Theology. 13(2):135-146. http://hdl.handle.net/10251/115248S13514613