La “filosofia architettonica” di Frei Otto: i concetti di forma, estetica ed etica e la loro ricezione

Form(-finding), aesthetics and ethics are key concepts in the philosophy of architect Frei Otto. Several of his ideas currently appear to be experiencing a renaissance. This is especially true for his concept of “form-finding” which frequently features in contemporary architectural discourse – albeit often with one of two common misconceptions: in the first, the term is used, or misused, as a catch-all for every imaginable approach to form, while in the second misconception “form-finding” is often presented simply as the genesis of form in a process of experimentation overlooking its inseparably intertwined theoretical background. For these reasons, this paper comprehensively examines Frei Otto’s own position on the meaning of these key concepts. Two cases demonstrate exemplarily the wider dissemination of his ideas: in the work and writings of Swiss architect Lisbeth Sachs from the 1970s, and, more currently, in the buildings and urban planning of Zaha Hadid with the theoretical underpinning of her professional partner, Patrick Schumacher

Conditioning the information in asset pricing

This thesis analyzes different theoretical and empirical aspects related to the use of the information in asset pricing. As a main innovation I extend the asset pricing literature proposing a new highly flexible technique for the estimation of the markets subjective distribution of future returns. Applying this technique to different problems I answer to some long-lasting puzzles present in literature. The contribution of this project to the literature is two-fold: first, in line with the new findings of Ross (2015) but from a fully different prospective I propose a new technique to estimate the market's subjective distribution of future returns using, jointly, stock and options data. Second, after studying the theoretical reason behind the superiority of the proposed technique, I use it for different empirical applications

Métamorphoses numériques des Bibliobus de Genève: pistes et axes de développement

L’objectif de ce travail est de définir des pistes de développement d’une offre numérique dans les Bibliobus de Genève. Pour ce faire, nous commencerons ce travail par un bref panorama des enjeux liés au numérique en bibliothèque et des diverses formes existantes de bibliobus en Europe et aux Etats-Unis. Nous verrons ensuite quelles offres numériques développer dans les Bibliobus de Genève, que ce soit en termes de collection ou d’accès aux ressources. Une troisième partie sera enfin consacrée aux implications que suscitera cette nouvelle offre, pour notre public et pour nous-même. Il s’agit ici d’un travail théorique, définissant des stratégies de développement possibles pour le Bibliobus, et non pas d’un mode d’emploi destiné à la mise en œuvre de ces stratégies

La médiation culturelle au sein de l’apprentissage :: une exposition, un thème = des apprentissages

Les musées sont des lieux culturels dont un grand nombre d’entrées proviennent du milieu scolaire. Ce public-là est motivé par les enseignants suite à l’intérêt porté aux apprentissages par le biais de la médiation culturelle, en accord avec le plan d’étude romand (PER). La mise à profit d’une telle institution pour favoriser les connaissances scolaires des élèves, l’apport d’un objet muséal dans l’acquisition de ces connaissances, l’intégration d’une visite au sein d’une séquence didactique et la place du médiateur culturel sont ici divers éléments questionnés, constituant la recherche de ce travail. Liant musée et apprentissages, mon cadre théorique comprend des réponses possibles à ces questionnements. Ce mémoire propose, à travers une méthodologie active, une séquence didactique conduisant les élèves à l’acquisition de nouveaux apprentissages dans la thématique donnée. Mes analyses se situent au niveau de ces derniers en proposant des pistes concernant leur influence. Finalement, l’apport d’une telle recherche dans ma future profession est exposé au terme de ce mémoire en proposant également diverses pistes pour la continuité de cette recherche dans l’intention de mettre à profit le musée, la médiation culturelle, comme outils de travail favorisant l’apprentissage

Extreme Value Analysis of Empirical Frame Coefficients and Implications for Denoising by Soft-Thresholding

Denoising by frame thresholding is one of the most basic and efficient methods for recovering a discrete signal or image from data that are corrupted by additive Gaussian white noise. The basic idea is to select a frame of analyzing elements that separates the data in few large coefficients due to the signal and many small coefficients mainly due to the noise \epsilon_n. Removing all data coefficients being in magnitude below a certain threshold yields a reconstruction of the original signal. In order to properly balance the amount of noise to be removed and the relevant signal features to be kept, a precise understanding of the statistical properties of thresholding is important. For that purpose we derive the asymptotic distribution of max_{\omega \in \Omega_n} || for a wide class of redundant frames (\phi_\omega^n: \omega \in \Omega_n}. Based on our theoretical results we give a rationale for universal extreme value thresholding techniques yielding asymptotically sharp confidence regions and smoothness estimates corresponding to prescribed significance levels. The results cover many frames used in imaging and signal recovery applications, such as redundant wavelet systems, curvelet frames, or unions of bases. We show that `generically' a standard Gumbel law results as it is known from the case of orthonormal wavelet bases. However, for specific highly redundant frames other limiting laws may occur. We indeed verify that the translation invariant wavelet transform shows a different asymptotic behaviour.Comment: [Content: 39 pages, 4 figures] Note that in this version 4 we have slightely changed the title of the paper and we have rewritten parts of the introduction. Except for corrected typos the other parts of the paper are the same as the original versions

Tilted black hole accretion disc models of Sagittarius A*: time-variable millimetre to near-infrared emission

High-resolution, multi-wavelength, and time-domain observations of the Galactic centre black hole candidate, Sgr A*, allow for a direct test of contemporary accretion theory. To date, all models have assumed alignment between the accretion disc and black hole angular momentum axes, but this is unjustified for geometrically thick accretion flows like that onto Sgr A*. Instead, we calculate images and spectra from a set of simulations of accretion flows misaligned ('tilted') by 15 degrees from the black hole spin axis and compare them with millimetre (mm) to near-infrared (NIR) observations. Non-axisymmetric standing shocks from eccentric fluid orbits dominate the emission, leading to a wide range of possible image morphologies. These effects invalidate previous parameter estimates from model fitting, including estimates of the dimensionless black hole spin, except possibly at low values of spin or tilt. At 1.3mm, the images have crescent morphologies, and the black hole shadow may still be accessible to future mm-VLBI observations. Shock heating leads to high energy electrons (T > 10^12 K), which can naturally produce the observed NIR flux, spectral index, and rapid variability ('flaring'). This NIR emission is uncorrelated with that in the mm, which also agrees with observations. These are the first models to self-consistently explain the time-variable mm to NIR emission of Sgr A*. Predictions of the model include significant structural changes observable with mm-VLBI on both the dynamical (hour) and Lense-Thirring precession (day-year) timescales; and ~30-50 microarcsecond changes in centroid position from extreme gravitational lensing events during NIR flares, detectable with the future VLT instrument GRAVITY. If the observed NIR emission is caused by shock heating in a tilted accretion disc, then the Galactic centre black hole has a positive, non-zero spin parameter (a > 0).Comment: 17 pages, 18 figures, submitted to MNRAS; for movies and version with high-res figures see http://astro.berkeley.edu/~jdexter/tiltedsgr