43 research outputs found
Localization of Sound Sources in a Room with One Microphone
Estimation of the location of sound sources is usually done using microphone
arrays. Such settings provide an environment where we know the difference
between the received signals among different microphones in the terms of phase
or attenuation, which enables localization of the sound sources. In our
solution we exploit the properties of the room transfer function in order to
localize a sound source inside a room with only one microphone. The shape of
the room and the position of the microphone are assumed to be known. The design
guidelines and limitations of the sensing matrix are given. Implementation is
based on the sparsity in the terms of voxels in a room that are occupied by a
source. What is especially interesting about our solution is that we provide
localization of the sound sources not only in the horizontal plane, but in the
terms of the 3D coordinates inside the room
Mesoporous Thin-film Materials Studied by Optical Waveguide Spectroscopy
A method was developed to access the interior of light-guiding structures in order to exploit the enhanced sensing potential of the highly confined electromagnetic field distributions, located within the core of a waveguide. The work presented in this thesis explores therefore the possibilities of optical waveguide spectroscopy utilising transparent mesoporous thin-film waveguides deposited on top of athin gold layer. These multi-layer assemblies are employed in a prism-coupling attenuated total internal reflection (ATR) configuration. The angular read-out of the reflected light intensity allows label-free detection schemes with high sensitivity to changes of the dielectric environment in the case of the presence of analyte molecules within the probing region. This optical waveguide spectroscopy technique has been used to study the real-timediffusion of Ruthenium 535-bisTBA (N-719) dye into mesoporous nanocrystalline titaniumdioxide films. The porous films were prepared on top of gold substrates and prism coupling was used to create a guided wave in the nanocrystalline film. Dying was carried out by bring the film into contact with a 3 x 10-4 moldm-3 dye solution and using optical waveguide spectroscopy to monitor the change in both the refractive index and theextinction coefficient of the nanoporous layer as dye diffused into the porous network. Dyeuptake in a 1.27 ÎŒm film was slow with the refractive index of the film still increasing after 22 hours.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
Structures in Tropes Networks: Toward a Formal Story Grammar
International audienceTropes are cultural narrative conventions that shape our expectations of stories. This paper proposes a new approach to examine movie content relying on tropes. It first presents the architecture of tropes ontology extracted from tvtropes.org, then studies the link prediction problem in trope bipartite networks and discusses the next challenges and numerous applications that ensue from this approach. In addition, we propose to assess the potential of tropes to be the lexicon units of a formal story grammar
Responsabilidad de proteger (los intereses): el caso de la intervenciĂłn de la OTAN en Libia
The Libyan regime was intervened in 2011 by NATO, after being accused of preparing a âmassacreâ against its own population. This intervention, led by France and the United States, was made in the name of Responsibility to protect, according to a UN mandate urging its members to use âall necessary meansâ to avoid âwidespread and systematic attacks on the civilian populationâ. Was this intervention, in fact, driven by moral values and the responsibility to protect the Libyan population? The purpose of this article is to demonstrate that NATOÂŽs intervention resembles a classical âregime changeâ operation mediated by âmaterialâ considerations, and that has little to do with humanitarian considerations. The intervention of NATO would also disrupt the proposals to implement a peaceful change, sweeping away hundreds of thousands of people, making Libya a failed state and provoking the emergence of multiple Islamist armed factionsEl rĂ©gimen libio fue intervenido en el 2011 por la OTAN, luego de haber sido acusado de estar preparando una âmasacreâ contra su propia poblaciĂłn. Esa intervenciĂłn, liderada por Francia y Estados Unidos, se hizo en nombre de la responsabilidad de proteger, de acuerdo con un mandato de la ONU que instaba a sus miembros a usar âtodos los medios necesariosâ para evitar âataques generalizados y sistemĂĄticos contra la poblaciĂłn civilâ. ÂżEstuvo en realidad esa intervenciĂłn impulsada por valores morales y la responsabilidad de proteger a la poblaciĂłn libia? El propĂłsito de este artĂculo es demostrar que la intervenciĂłn de la OTAN se asemeja a una clĂĄsica operaciĂłn de âcambio de rĂ©gimenâ mediada por consideraciones âmaterialesâ y que poco tuvo que ver con consideraciones humanitarias. La intervenciĂłn de la OTAN, asimismo, desestructurarĂa las propuestas para implementar un cambio pacĂfico, arrasando consigo a centenares de miles de personas, convirtiendo a Libia en un Estado fallido y provocando la apariciĂłn de mĂșltiples facciones armadas islamista
Varying numbers and positions of carboxylate groups on Ru dyes for dye-sensitized solar cells:Uptake on TiO<sub>2</sub>, cell performance and cell stability
Psychosis Endophenotypes: A Gene-Set-Specific Polygenic Risk Score Analysis
BACKGROUND AND HYPOTHESIS: Endophenotypes can help to bridge the gap between psychosis and its genetic predispositions, but their underlying mechanisms remain largely unknown. This study aims to identify biological mechanisms that are relevant to the endophenotypes for psychosis, by partitioning polygenic risk scores into specific gene sets and testing their associations with endophenotypes. STUDY DESIGN: We computed polygenic risk scores for schizophrenia and bipolar disorder restricted to brain-related gene sets retrieved from public databases and previous publications. Three hundred and seventy-eight gene-set-specific polygenic risk scores were generated for 4506 participants. Seven endophenotypes were also measured in the sample. Linear mixed-effects models were fitted to test associations between each endophenotype and each gene-set-specific polygenic risk score. STUDY RESULTS: After correction for multiple testing, we found that a reduced P300 amplitude was associated with a higher schizophrenia polygenic risk score of the forebrain regionalization gene set (mean difference per SD increase in the polygenic risk score: -1.15 ”V; 95% CI: -1.70 to -0.59 ”V; P = 6 à 10-5). The schizophrenia polygenic risk score of forebrain regionalization also explained more variance of the P300 amplitude (R2 = 0.032) than other polygenic risk scores, including the genome-wide polygenic risk scores. CONCLUSIONS: Our finding on reduced P300 amplitudes suggests that certain genetic variants alter early brain development thereby increasing schizophrenia risk years later. Gene-set-specific polygenic risk scores are a useful tool to elucidate biological mechanisms of psychosis and endophenotypes, offering leads for experimental validation in cellular and animal models
Time-Resolved Indirect Nanoplasmonic Sensing Spectroscopy of Dye Molecule Interactions with Dense and Mesoporous TiO 2
Sparse and Parametric Modeling with Applications to Acoustics and Audio
Recent advances in signal processing, machine learning and deep learning with sparse intrinsic structure of data have paved the path for solving inverse problems in acoustics and audio. The main task of this thesis was to bridge the gap between the powerful mathematical tools and challenging problems in acoustics and audio. This thesis consists out of two main parts.
The first part of the thesis focuses on the questions related to acoustic simulations that comply with the "real world" constraints and the acoustic data acquisition inside of closed spaces. The simulated and measured data is used to solve various types of inverse problems with underlying sparsity. By using the technique of compressed sensing, we estimate the room modes, localize sound sources in a room and also estimate room's geometry. The Finite Rate of Innovation technique is coupled with non-convex optimization for the task of blind deconvolution in the context of echo retrieval. We also invent a new statistical measure for the echo density for the purpose of detecting the type of acoustic environment from its acoustic impulse response, even beyond fully closed spaces. These types solutions can have an application in the blooming domain of virtual, augmented and mixed reality for sound compression and rendering.
The second part of the thesis focuses on the recent trends in machine learning that are centered around deep learning. Large scale data acquisition of acoustic impulse responses is still a challenging and very expensive task. Also, the existing databases tend to be too heterogeneous to be merged, due to the lack of the standardization of the acquisition procedure, and also the available metadata tends to be incomplete. In order to keep up with the recent trends and avoid the difficulties that come from the lack of large scale acoustical data, the last part of research in this thesis has diverged from the rest and is devoted to deep learning applied to classification problems in audio with the focus on speech and environmental sounds. The learning procedure is parametrized, which results in an off-grid learning procedure for audio classification. Learned trends align with perceptual trends, which helps the interpretation of the achieved results