1,721,288 research outputs found
UN MODELLO DI CONOSCENZA PER LA RAPPRESENTAZIONE DEL PATRIMONIO COSTRUITO
No full textNell’ambito del processo edilizio dei beni culturali, inteso come un sistema strutturato di attività finalizzate alla ricerca, la conservazione e la gestione dei beni architettonici, tutte le operazioni compiute dai diversi attori coinvolti sono profondamente influenzate dalla conoscenza derivata da una fase complessa di documentazione e l'eventuale mancanza o errata interpretazione dei dati possono portare a decisioni sbagliate e danni anche irreparabili al manufatto. Nella pratica corrente, la rappresentazione e la gestione della conoscenza legata al patrimonio costruito hanno mostrato diverse limitazioni per la difficoltà di trattare grandi quantità di dati estremamente eterogenei.
Su tali basi, la presente ricerca ha come obbiettivo quello di estendere gli approcci e le tecnologie proprie del web semantico alla modellazione della conoscenza relativa al patrimonio architettonico al fine di fornire una rappresentazione integrata e multidisciplinare del manufatto e delle conoscenze necessarie per supportare qualsiasi decisione o qualsiasi attività di indagine, interpretazione, intervento e gestione.
Per questo scopo, è stato sviluppato un sistema basato su ontologie, per rappresentare la conoscenza relativa al manufatto e suoi contesti attraverso la formalizzazione di entità specifiche per il dominio d’interesse e delle relazioni che intercorrono tre di esse. Questo approccio permette di includere in un modello coerente ed omogeneo sia le conoscenze raccolte attraverso campagne d’indagine dirette sia quelle non direttamente deducibili dal manufatto ma riconducibili ad esso (ad es. informazioni storiche o di contesto).
Infine, il modello è stato applicato al processo di ricerca e documentazione del tempio romano di Castore e Polluce a Cori e dell’Oratorio di San Saba a Roma. In questi casi di studio, la conoscenza relativa ai manufatti architettonici è stata formalizzata attraverso l’editor di ontologie Protégé, mentre è stato utilizzato un ambiente BIM per fornire una rappresentazione schematica delle sue caratteristiche fisiche.
L'introduzione di questo ambiente di modellazione vuole migliorare l’attuale rappresentazione e gestione delle informazioni nei processi legati al patrimonio costruito, passando da un approccio document-based a uno model-based. Come risultato, tutti i dati, le informazioni, e le conoscenze relative ad un edificio storico, raccolte e documentate da diverse attività di indagine saranno integrati in un unico modello esaustivo e sempre aggiornato.
Questa esperienza ha illustrato le potenzialità dell'approccio proposto per documentare e analizzare in modo innovativo l'ambiente storico costruito e per sostenere tutte le indagini, le interpretazioni e le attività di intervento ad esso correlate
Effects of anisotropic supports on the stability of parametrically excited slender rotors
No full textThis study is aimed at investigating the effects of anisotropic supports on the stability of slender rotors parametrically excited by external loads. An axisymmetric shaft described by scaling a spinning Timoshenko beam on anisotropic supports is studied, loaded by oscillating axial end thrust and twisting moment, with the possibility of carrying additional inertial elements like discs, which represents a model including all the general features of slender rotors which are relevant for this kind of stability analysis, gyroscopic effects comprised. Stability is studied after discretization of the equations of motion into a set of coupled ordinary differential Mathieu-Hill equations. The influence on stability of angular speed combined with anisotropy in the supports (including principal stiffness, principal damping and cross-elements) is analysed with respect to frequency and amplitude of the external loads on stability charts in the form of Ince-Strutt diagrams. The occurrence of different kinds of critical solutions, simple and combination, is investigated, highlighting their dependency on both the degree of anisotropy in the supports and angular speed
Frequency domain analysis of a fractional derivative SDOF system
No full textThis paper presents a study of the frequency domain
behaviour of a single degree of freedom (SDOF) system with a
fractional derivative model, named Fractional Kelvin-Voigt.
Frequency response functions (FRFs) as receptance and
transmissibility are analytically studied. Then the model is
applied to describe the dynamic behaviour of a magnetomechanic
system in the frequency domain, consisting of a body
of para or dia-magnetic material vibrating in a field created by a
pair of magnets
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Finite element analysis of vibrating linear systems with fractional derivative viscoelastic models
No full textFractional derivative rheological models are known to be very effective in describing the viscoelastic behaviour of materials, especially of polymers, and when applied to dynamic problems the resulting equations of motion, after a fractional state-space expansion, can still be studied in terms of modal analysis. But the growth in matrix dimensions carried by this expansion is in general so fast to make the calculations exceedingly cumbersome. This paper presents a method for reducing the computational effort due to finite element (FE) analysis of vibrating linear systems with a fractional derivative viscoelastic model, namely the Fractional Kelvin-Voigt. The proposed method may be applied also to problems involving other fractional derivative linear models, and it takes under control the computational effort by reducing the main eigenproblem of large dimension to the solution of two standard related eigenproblems of lower size. Numerical examples are provided in order to validate both the accuracy and the efficiency of the proposed methodolog
Variations on the Author
Full text link“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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Algorithm for diagnosis of infective endocarditis after transcatheter aortic valve replacement
No full text- …
