3,401 research outputs found
Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Variable order smoothness priors for ill-posed inverse problems
No full textIn this article we discuss ill-posed inverse problems, with an emphasis on hierarchical variable order regularization. Traditionally, smoothness penalties in Tikhonov regularization assume a fixed degree of regularity of the unknown over the whole domain. Using a Bayesian framework with hierarchical priors, we derive a prior model, formally represented as a convex combination of autoregressive (AR) models, in which the parameter controlling the mixture of the AR models can dynamically change over the domain of the signal. Moreover, the mixture parameter itself is an unknown and is to be estimated using the data. Also, the variance of the innovation processes in the AR model is a free parameter, which leads to conditionally Gaussian priors that have been previously shown to be much more flexible than the traditional Gaussian priors, capable, e.g., to deal with sparsity type prior information. The suggested method, the Weighted Variable Order Autoregressive model (WVO-AR) is tested with a computed example.Fil: Calvetti, Daniela. Case Western Reserve University; Estados UnidosFil: Somersalo, Erkki. Case Western Reserve University; Estados UnidosFil: Spies, Ruben Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Matemática Aplicada "Litoral"; Argentin
Brain Activity Mapping from MEG Data via a Hierarchical Bayesian Algorithm with Automatic Depth Weighting
No full textA recently proposed iterated alternating sequential (IAS) MEG inverse solver algorithm, based on the coupling of a hierarchical Bayesian model with computationally efficient Krylov subspace linear solver, has been shown to perform well for both superficial and deep brain sources. However, a systematic study of its ability to correctly identify active brain regions is still missing. We propose novel statistical protocols to quantify the performance of MEG inverse solvers, focusing in particular on how their accuracy and precision at identifying active brain regions. We use these protocols for a systematic study of the performance of the IAS MEG inverse solver, comparing it with three standard inversion methods, wMNE, dSPM, and sLORETA. To avoid the bias of anecdotal tests towards a particular algorithm, the proposed protocols are Monte Carlo sampling based, generating an ensemble of activity patches in each brain region identified in a given atlas. The performance in correctly identifying the active areas is measured by how much, on average, the reconstructed activity is concentrated in the brain region of the simulated active patch. The analysis is based on Bayes factors, interpreting the estimated current activity as data for testing the hypothesis that the active brain region is correctly identified, versus the hypothesis of any erroneous attribution. The methodology allows the presence of a single or several simultaneous activity regions, without assuming that the number of active regions is known. The testing protocols suggest that the IAS solver performs well with both with cortical and subcortical activity estimation
Sparse reconstructions from few noisy data: analysis of hierarchical Bayesian models with generalized gamma hyperpriors
No full textSolving inverse problems with sparsity promoting regularizing penalties can be recast in the Bayesian framework as finding a maximum a posteriori (MAP) estimate with sparsity promoting priors. In the latter context, a computationally convenient choice of prior is the family of conditionally Gaussian hierarchical models for which the prior variances of the components of the unknown are independent and follow a hyperprior from a generalized gamma family. In this paper, we analyze the optimization problem behind the MAP estimation and identify hyperparameter combinations that lead to a globally or locally convex optimization problem. The MAP estimation problem is solved using a computationally efficient alternating iterative algorithm. Its properties in the context of the generalized gamma hypermodel and its connections with some known sparsity promoting penalty methods are analyzed. Computed examples elucidate the convergence and sparsity promoting properties of the algorithm
Imparare le lingue per abbracciare il mondo
No full textL’autrice che si colloca, come Daniela Zorzi, tra i fautori di una linguistica “impegnata”, propone in ricordo della studiosa amica, una riflessione sul ruolo cruciale del multilinguismo e delle lingue- culture, per il successo professionale e il benessere sociale, nella società contemporanea. Il multilinguismo appare come un’urgenza educativa che interpella studiosi e formatori a tutti i livelli al fine di promuovere nei giovani un apprendimento consapevole efficace ed autonomo.Multilingualism constitutes an urgent objective for education, which needs to involve teachers and researchers at all levels if we are to promote effective and autonomous learning in the young. Like Daniela Zorzi, the author considers herself a socially engaged linguist, and in memory of her friend’s work, offers a reflection on the key roles of languages and cultures and of multilingualism for professional success and social welfare today
Reclamações ambientais em Aveiro, Portugal: atores, preocupações, padrão territorial e resoluções
No full textThis paper presents an environmental diagnosis based on public complaints on environmental
issues submitted to the Environmental Department of the Aveiro City Council, Portugal, between
2000 and 2005. It discusses the potential influences of these in local environmental planning
and governance. The paper has been organised into five sections. The first of these introduces
the study. The second section focuses on the conceptual approaches relating to environmental
grassroots movements, the main actors involved in these movements and the role played by
local government. It also contains a brief review of the most recent urban environmental
quality challenges in the European context together with a description of the main features of
the associated political and legal framework in Portugal. The third section describes the case
study and the methodology used. The results of the empirical study are detailed in the fourth
section. The final section critically analyses these results with emphases on the temporal
evolution of the submission of complaints, the actors involved, the local environmental problems
and their associated spatial pattern as well as the responses given by the City Council. This
information may then be used to provide a useful indicator for the perception of environmental
quality as well as a credible instrument for the visualisation and evaluation of local performance
in terms of environmental planning and management.AlBan Programme - n. E05M053040B
Jak rozumieć „historyczność” biblijnego Daniela? Różne kierunki wyjaśniania orędzia Księgi Daniela
No full textThe subject of this article is the issue of the historicity of the figure of Daniel, who is the main character of the biblical book bearing his name. The question of whether Daniel is a historical or just a literary figure is important because it influences the exegesis of the text of the Book of Daniel. First, the author will indicate the reasons for questioning the historicity of Daniel, and then he will present different approaches to interpreting the content of the Book of Daniel.Przedmiotem artykułu jest kwestia historyczności postaci Daniela, który jest głównym bohaterem księgi biblijnej noszącej jego imię. Pytanie o to, czy Daniel jest postacią historyczną, czy tylko literacką, jest ważne z tego powodu, że ma wpływ na egzegezę tekstu Księgi Daniela. Najpierw autor wskaże powody, na podstawie których podważa się historyczność Daniela, a następnie przedstawi różne podejścia w interpretacji treści Księgi Daniela
Computational issues in linear multistep method particle filtering
No full textThe LMM PF is a methodology for solving the state and parameter estimation problem for ODEs system, rooted into a Bayesian framework and for it we consider a test problem with known solution to investigate in depth the error sources and how they depend on the choice of LMM used for the numerical integration. We conclude by looking at the effect on the error of replacing LMM with Runge-Kutta (RK) class integration methods
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