1,720,969 research outputs found
Lezioni di meccanica elementare e oltre
No full textIl libro espone le idee fondanti della Meccanica Classica da un punto di vista elementare adatto agli studenti del primo anno del corso di Laurea in Matematica. Partendo dalle nozioni di spazio, tempo, massa e le loro misure, si introducono i concetti di lavoro e di flusso su tre esempi di forze elementari: quella costante, quella elastica e quella newtoniana che decresce con l'inverso del quadrato della distanza. Su di esse viene costruita la nozione di conservatività e per la forza newtoniana viene dimostrato il celebre teorema sul campo gravitazionale della sfera piena e omogenea. I concetti di teoria scientifica, modello matematico e realtà fenomenologica e le loro reciproche relazioni emergono progressivamente e in modo naturale. Gli strumenti matematici elementari in grado di trattare questa parte della fisica matematica vengono anche utilizzati per introdurre le basi del calcolo delle variazioni attraverso il principio di Fermat, di teoria della relatività ristretta di Einstein, e di calcolo delle probabilità per la passeggiata aleatoria browniana. Il manuale che ne emerge è quindi un corso introduttivo alla teoria del moto secondo la meccanica classica, relativistica e statistica. Il volume è suddiviso in capitoli ciascuno dei quali occupa mediamente una settimana di lezioni ed esercitazioni con esempi e problemi risolti
An inference problem in a mismatched setting: a spin-glass model with Mattis interaction
Full text linkThe Wigner spiked model in a mismatched setting is studied with the finite temperature Statistical Mechanics approach through its representation as a Sherrington-Kirkpatrick model with added Mattis interaction. The exact solution of the model with Ising spins is rigorously proved to be given by a variational principle on two order parameters, the Parisi overlap distribution and the Mattis magnetization. The latter is identified by an ordinary variational principle and turns out to concentrate in the thermodynamic limit. The solution leads to the computation of the Mean Square Error of the mismatched reconstruction. The Gaussian signal distribution case is investigated and the corresponding phase diagram is identified
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
Mathematical Methods and Models in Machine Learning
No full textArtificial Intelligence is profoundly and quickly changing the technological profile of our society and yet machine learning, its disruptive spearhead, although filled with brilliant heuristic solutions has almost no theoretical basis from a strictly scientific point of view.
The gap between the increasing performance of deep learning and its understanding is therefore a very relevant scientific theme that calls for a strong participation in research efforts from the fields of Mathematics and Mathematical Physics.
The identification of the correct mathematical models and their analysis is of fundamental importance toward the discovery of a theory that could allow to exploit at best the potential and understand the limits of this technology.
The purpose of the conference is to present recent results on mathematical methods and models related to machine learning and link researchers coming from different areas
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
- …
