9 resultados para recursive detrending
em AMS Tesi di Dottorato - Alm@DL - Università di Bologna
Resumo:
Seyfert galaxies are the closest active galactic nuclei. As such, we can use
them to test the physical properties of the entire class of objects. To investigate
their general properties, I took advantage of different methods of data analysis. In
particular I used three different samples of objects, that, despite frequent overlaps,
have been chosen to best tackle different topics: the heterogeneous BeppoS AX
sample was thought to be optimized to test the average hard X-ray (E above 10 keV)
properties of nearby Seyfert galaxies; the X-CfA was thought the be optimized to
compare the properties of low-luminosity sources to the ones of higher luminosity
and, thus, it was also used to test the emission mechanism models; finally, the
XMM–Newton sample was extracted from the X-CfA sample so as to ensure a
truly unbiased and well defined sample of objects to define the average properties
of Seyfert galaxies.
Taking advantage of the broad-band coverage of the BeppoS AX MECS and
PDS instruments (between ~2-100 keV), I infer the average X-ray spectral propertiesof nearby Seyfert galaxies and in particular the photon index (
Resumo:
The "sustainability" concept relates to the prolonging of human economic systems with as little detrimental impact on ecological systems as possible. Construction that exhibits good environmental stewardship and practices that conserve resources in a manner that allow growth and development to be sustained for the long-term without degrading the environment are indispensable in a developed society. Past, current and future advancements in asphalt as an environmentally sustainable paving material are especially important because the quantities of asphalt used annually in Europe as well as in the U.S. are large. The asphalt industry is still developing technological improvements that will reduce the environmental impact without affecting the final mechanical performance. Warm mix asphalt (WMA) is a type of asphalt mix requiring lower production temperatures compared to hot mix asphalt (HMA), while aiming to maintain the desired post construction properties of traditional HMA. Lowering the production temperature reduce the fuel usage and the production of emissions therefore and that improve conditions for workers and supports the sustainable development. Even the crumb-rubber modifier (CRM), with shredded automobile tires and used in the United States since the mid 1980s, has proven to be an environmentally friendly alternative to conventional asphalt pavement. Furthermore, the use of waste tires is not only relevant in an environmental aspect but also for the engineering properties of asphalt [Pennisi E., 1992]. This research project is aimed to demonstrate the dual value of these Asphalt Mixes in regards to the environmental and mechanical performance and to suggest a low environmental impact design procedure. In fact, the use of eco-friendly materials is the first phase towards an eco-compatible design but it cannot be the only step. The eco-compatible approach should be extended also to the design method and material characterization because only with these phases is it possible to exploit the maximum potential properties of the used materials. Appropriate asphalt concrete characterization is essential and vital for realistic performance prediction of asphalt concrete pavements. Volumetric (Mix design) and mechanical (Permanent deformation and Fatigue performance) properties are important factors to consider. Moreover, an advanced and efficient design method is necessary in order to correctly use the material. A design method such as a Mechanistic-Empirical approach, consisting of a structural model capable of predicting the state of stresses and strains within the pavement structure under the different traffic and environmental conditions, was the application of choice. In particular this study focus on the CalME and its Incremental-Recursive (I-R) procedure, based on damage models for fatigue and permanent shear strain related to the surface cracking and to the rutting respectively. It works in increments of time and, using the output from one increment, recursively, as input to the next increment, predicts the pavement conditions in terms of layer moduli, fatigue cracking, rutting and roughness. This software procedure was adopted in order to verify the mechanical properties of the study mixes and the reciprocal relationship between surface layer and pavement structure in terms of fatigue and permanent deformation with defined traffic and environmental conditions. The asphalt mixes studied were used in a pavement structure as surface layer of 60 mm thickness. The performance of the pavement was compared to the performance of the same pavement structure where different kinds of asphalt concrete were used as surface layer. In comparison to a conventional asphalt concrete, three eco-friendly materials, two warm mix asphalt and a rubberized asphalt concrete, were analyzed. The First Two Chapters summarize the necessary steps aimed to satisfy the sustainable pavement design procedure. In Chapter I the problem of asphalt pavement eco-compatible design was introduced. The low environmental impact materials such as the Warm Mix Asphalt and the Rubberized Asphalt Concrete were described in detail. In addition the value of a rational asphalt pavement design method was discussed. Chapter II underlines the importance of a deep laboratory characterization based on appropriate materials selection and performance evaluation. In Chapter III, CalME is introduced trough a specific explanation of the different equipped design approaches and specifically explaining the I-R procedure. In Chapter IV, the experimental program is presented with a explanation of test laboratory devices adopted. The Fatigue and Rutting performances of the study mixes are shown respectively in Chapter V and VI. Through these laboratory test data the CalME I-R models parameters for Master Curve, fatigue damage and permanent shear strain were evaluated. Lastly, in Chapter VII, the results of the asphalt pavement structures simulations with different surface layers were reported. For each pavement structure, the total surface cracking, the total rutting, the fatigue damage and the rutting depth in each bound layer were analyzed.
Resumo:
Visual tracking is the problem of estimating some variables related to a target given a video sequence depicting the target. Visual tracking is key to the automation of many tasks, such as visual surveillance, robot or vehicle autonomous navigation, automatic video indexing in multimedia databases. Despite many years of research, long term tracking in real world scenarios for generic targets is still unaccomplished. The main contribution of this thesis is the definition of effective algorithms that can foster a general solution to visual tracking by letting the tracker adapt to mutating working conditions. In particular, we propose to adapt two crucial components of visual trackers: the transition model and the appearance model. The less general but widespread case of tracking from a static camera is also considered and a novel change detection algorithm robust to sudden illumination changes is proposed. Based on this, a principled adaptive framework to model the interaction between Bayesian change detection and recursive Bayesian trackers is introduced. Finally, the problem of automatic tracker initialization is considered. In particular, a novel solution for categorization of 3D data is presented. The novel category recognition algorithm is based on a novel 3D descriptors that is shown to achieve state of the art performances in several applications of surface matching.
Resumo:
Il saggio, genere di confine (Grenzgänger-Textsorte) per eccellenza, la cui indefinibilità è topos, si profila tuttora come terra incognita nell’àmbito delle scienze della traduzione. La presente ricerca mira a enucleare un modello traduttologico olistico per la traduzione del saggio. In feconda alternativa alla dicotomia approccio ermeneutico-letterario vs. approccio linguistico, la prospettiva teorico-metodologica del lavoro integra linee di ricerca filologico-letterarie e linguistico-testuali. Tale sguardo multiprospettico, l’unico in grado di dar conto della complessità del genere, permette di collocare operativamente il saggio e le sue varianti testuali principali (Textsortenvarianten), dal saggio specialistico (fachlicher Essay) al saggio poetico (poetischer Essay) sul continuum delle forme testuali comprese entro le dimensioni (scientifica, pragmatica, estetica) del Denkhandeln. Dalla produttiva intersezione tra la riflessione dell’Essayforschung classica e contemporanea e le più recenti indagini linguistico-testuali sulle forme del saggismo scientifico, si perviene alla formulazione di una definitio per proprietates del saggio. Segue lo sviluppo di un modello traduttologico olistico, che tesaurizza il proprio paradigma antropologico, la riflessione filosofico-ermeneutica e le acquisizioni della linguistica testuale, articolandosi attraverso le fasi ricorsive e interagenti di ricezione olistica, analisi poetico-ermeneutica e retorico-stilistica, progettazione linguistico-cognitiva, formulazione e revisione. L’approccio olistico così delinatosi viene quindi vagliato nella sua proficuità in sede applicativa. Funge da banco di prova un vero e proprio “caso limite” per complessità e qualità letteraria, ovvero il «poetischer Essay» del poeta, saggista e traduttore Durs Grünbein, una delle voci più acclamate nel panorama contemporaneo. La sezione pratica presenta infine l’inedita traduzione italiana dei saggi grünbeiniani Den Körper zerbrechen e Die Bars von Atlantis.
Resumo:
The aim of the present work is to contribute to a better understanding of the relation between organization theory and management practice. It is organized as a collection of two papers, a theoretical and conceptual contribution and an ethnographic study. The first paper is concerned with systematizing different literatures inside and outside the field of organization studies that deal with the theory-practice relation. After identifying a series of positions to the theory-practice debate and unfolding some of their implicit assumptions and limitations, a new position called entwinement is developed in order to overcome status quo through reconciliation and integration. Accordingly, the paper proposes to reconceptualize theory and practice as a circular iterative process of action and cognition, science and common-sense enacted in the real world both by organization scholars and practitioners according to purposes at hand. The second paper is the ethnographic study of an encounter between two groups of expert academics and practitioners occasioned by a one-year executive business master in an international business school. The research articulates a process view of the knowledge exchange between management academics and practitioners in particular and between individuals belonging to different communities of practice, in general, and emphasizes its dynamic, relational and transformative mechanisms. Findings show that when they are given the chance to interact, academics and practitioners set up local provisional relations that enable them to act as change intermediaries vis-a-vis each other’s worlds, without tying themselves irremediably to each other and to the scenarios they conjointly projected during the master’s experience. Finally, the study shows that provisional relations were accompanied by a recursive shift in knowledge modes. While interacting, academics passed from theory to practical theorizing, practitioners passed from an involved practical mode to a reflexive and quasi-theoretical one, and then, as exchanges proceeded, the other way around.
Resumo:
Il presente lavoro si rivolge all’analisi del ruolo delle forme metaforiche nella divulgazione della fisica contemporanea. Il focus è sugli aspetti cognitivi: come possiamo spiegare concetti fisici formalmente complessi ad un audience di non-esperti senza ‘snaturarne’ i significati disciplinari (comunicazione di ‘buona fisica’)? L’attenzione è sulla natura stessa della spiegazione e il problema riguarda la valutazione dell’efficacia della spiegazione scientifica a non-professionisti. Per affrontare tale questione, ci siamo orientati alla ricerca di strumenti formali che potessero supportarci nell’analisi linguistica dei testi. La nostra attenzione si è rivolta al possibile ruolo svolto dalle forme metaforiche nella costruzione di significati disciplinarmente validi. Si fa in particolare riferimento al ruolo svolto dalla metafora nella comprensione di nuovi significati a partire da quelli noti, aspetto fondamentale nel caso dei fenomeni di fisica contemporanea che sono lontani dalla sfera percettiva ordinaria. In particolare, è apparsa particolarmente promettente come strumento di analisi la prospettiva della teoria della metafora concettuale. Abbiamo allora affrontato il problema di ricerca analizzando diverse forme metaforiche di particolare rilievo prese da testi di divulgazione di fisica contemporanea. Nella tesi viene in particolare discussa l’analisi di un case-study dal punto di vista della metafora concettuale: una analogia di Schrödinger per la particella elementare. I risultati dell’analisi suggeriscono che la metafora concettuale possa rappresentare uno strumento promettente sia per la valutazione della qualità delle forme analogiche e metaforiche utilizzate nella spiegazione di argomenti di fisica contemporanea che per la creazione di nuove e più efficaci metafore. Inoltre questa prospettiva di analisi sembra fornirci uno strumento per caratterizzare il concetto stesso di ‘buona fisica’. Riteniamo infine che possano emergere altri risultati di ricerca interessanti approfondendo l’approccio interdisciplinare tra la linguistica e la fisica.
Resumo:
This doctoral thesis is devoted to the study of the causal effects of the maternal smoking on the delivery cost. The interest of economic consequences of smoking in pregnancy have been studied fairly extensively in the USA, and very little is known in European context. To identify the causal relation between different maternal smoking status and the delivery cost in the Emilia-Romagna region two distinct methods were used. The first - geometric multidimensional - is mainly based on the multivariate approach and involves computing and testing the global imbalance, classifying cases in order to generate well-matched comparison groups, and then computing treatment effects. The second - structural modelling - refers to a general methodological account of model-building and model-testing. The main idea of this approach is to decompose the global mechanism into sub-mechanisms though a recursive decomposition of a multivariate distribution.
Resumo:
La ricerca sviluppa le più recenti proposte teoriche dell'antropologia interpretativa, applicandole alla teoria della letteratura. Si concentra sull'ipotesto antropologico attivo nell'opera di Elsa Morante, con particolare riferimento alla produzione successiva agli anni Sessanta (Il mondo salvato dai ragazzini, 1968; La Storia, 1974; Aracoeli, 1982), in cui si verifica la concentrazione del materiale etno-antropologico di derivazione demartiniana. La tesi si propone di sondare la prolificità del rapporto intertestuale Morante-De Martino, soprattutto mediante la ricorrenza di alcuni luoghi significanti che accomunano la ricerca poetica e quella scientifica degli autori, uniti da una fondamentale rielaborazione del concetto di "umanesimo". Centrale, a questo proposito, diviene la nozione di "crisi" della persona, direttamente collegata al vissuto da "fine del mondo" e alla percezione apocalittica post-atomica. Alla crisi del soggetto contemporaneo si guarda nei termini di una risoluzione culturale, che chiama direttamente in causa il rapporto tra letteratura e ritualità. Secondo la prospettiva sociologica durkheimiana, si indagano i momenti della piacularità e della festa, ricorsivi nella scrittura morantiana, come fondanti il discorso (la narrazione mitografica) della comunità. Di qui, la riflessione si attesta sulle strategie della comunicazione finzionale in ambito etno-antropologico, con attenzione all'autorialità dello stesso antropologo sul campo. Non mancano raffronti con le esperienze letterarie più significative nell'orizzonte culturale delineato: in particolar modo, si tiene in considerazione il fondamentale rapporto Morante-Pasolini.
Resumo:
In this thesis we provide a characterization of probabilistic computation in itself, from a recursion-theoretical perspective, without reducing it to deterministic computation. More specifically, we show that probabilistic computable functions, i.e., those functions which are computed by Probabilistic Turing Machines (PTM), can be characterized by a natural generalization of Kleene's partial recursive functions which includes, among initial functions, one that returns identity or successor with probability 1/2. We then prove the equi-expressivity of the obtained algebra and the class of functions computed by PTMs. In the the second part of the thesis we investigate the relations existing between our recursion-theoretical framework and sub-recursive classes, in the spirit of Implicit Computational Complexity. More precisely, endowing predicative recurrence with a random base function is proved to lead to a characterization of polynomial-time computable probabilistic functions.