1,721,030 research outputs found
Postfazione
No full textVale la pena di cominciare prima possibile ad appropriarsi di un modo di ragionare solo apparentemente non comune. Cominciare con le fiabe è una ottima partenza. Anche perché l’idea di effettuare conteggi, di costruire dei gruppi che differiscono perché possono essere riassunti da numeri diversi, di dare risalto alla diversità non è per niente stravagante. Se si hanno parecchie informazioni non è stupido perdere qualcosa per riassumerle tramite delle sintesi che in sostanza dicono la stessa cosa. D’altro canto, è positivo riconoscere che la diversità è una ricchezza e che, casomai, andrebbe misurata. Le probabilità non sono una ambiguità da evitare, ma valutazioni utili, alla portata di tutti, da tenere presente quando si può. Anche prendere una decisione qualunque, dalle possibili conseguenze negative che ricadono su chi compie l’azione, è qualcosa che si fa regolarmente, a qualunque età. Riguardo alla decisione, le esperienze precedenti sono davvero importanti, e agire in funzione di quanto si è imparato dal passato piuttosto che ripartire sempre daccapo è molto appropriato.
La forza delle nozioni, davvero di base, che sono illustrate in queste fiabe, è però che il ragionamento nel mondo del variabile e dell’incerto ha delle basi matematiche: a fianco delle nozioni che sono state accennate ci sono dimostrazioni rigorose. Dietro ai metodi che sono accennati c’è ragionamento scientifico: le fiabe non presentano solo conclusioni occasionali e basate principalmente sul buonsenso. Il modo di fornire insegnamento di base nella scuola è cambiato, negli anni più recenti, e tiene conto degli aspetti appena elencati, che sono, usando una parola che può suscitare sospetto e scarsa simpatia, aspetti statistici. Essi forniscono un ottimo collante alla considerazione congiunta delle discipline da più tempo popolari nei processi di apprendimento
Measuring heterogeneity in urban expansion via spatial entropy
Full text linkThe lack of efficiency in urban diffusion is a debated issue, important for biologists,
urban specialists, planners and statisticians, both in developed and new
developing countries. Many approaches have been considered to measure urban
sprawl, roughly identified as chaotic urban expansion; such idea of chaos is
here linked to the concept of entropy. Entropy, firstly introduced in information
theory, has rapidly become a standard tool in ecology, biology, and geography
to measure the degree of heterogeneity among observations; in such contexts,
entropy measures should include spatial information. The aim of this paper is
to employ a rigorous spatial entropy-based approach to measure urban sprawl
associated to the diffusion of metropolitan cities. In order to assess the performance
of the considered measures, a comparative study is run over archetypical
urban scenarios; afterwards, measures are used to quantify the degree of disorder
in the urban expansion of three cities in Europe. Results are easily interpretable
and can be used both as absolute measures of urban sprawl and for comparison
over space and time
SpatEntropy: Spatial Entropy Measures in R
No full textThis article illustrates how to measure the heterogeneity of spatial data
presenting a finite number of categories via computation of spatial entropy.
The R package SpatEntropy contains functions for the computation of entropy and
spatial entropy measures. The extension to spatial entropy measures is a unique
feature of SpatEntropy. In addition to the traditional version of Shannon's
entropy, the package includes Batty's spatial entropy, O'Neill's entropy, Li
and Reynolds' contagion index, Karlstrom and Ceccato's entropy, Leibovici's
entropy, Parresol and Edwards' entropy and Altieri's entropy. The package is
able to work with both areal and point data. This paper is a general
description of SpatEntropy, as well as its necessary theoretical background,
and an introduction for new users
New perspectives in the measurement of biodiversity
No full textEntropy is widely used in biodiversity studies, where data often present complex interactions. Difficulties arise in linking entropy to available covariates or data dependence structures, as all existing entropy estimators assume independence. We take a Bayesian model-based approach and focus on estimating the probabilities which compose an entropy index, accounting for data dependence. This way, the entropy estimate is not a single value, rather it becomes a curve or a two dimensional surface according to the data structure. We obtain an interpretable index of the latent biodiversity of a system
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
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
Stima non parametrica della densita' e regressione non parametrica per dati imprecisi
No full textDottorato di ricerca in metodologia statistica per la ricerca scientifica. 12. ciclo. A.a. 1999-2000. Coordinatore Daniela Cocchi. Tutore Mario Di BaccoConsiglio Nazionale delle Ricerche - Biblioteca Centrale - P.le Aldo Moro, 7 , Rome; Biblioteca Nazionale Centrale - P.za Cavalleggeri, 1, Florence / CNR - Consiglio Nazionale delle RichercheSIGLEITItal
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