1,721,028 research outputs found
The curvature of optimal control problems with applications to sub-Riemannian geometry
Full text linkOptimal control theory is an extension of the calculus of variations, and deals with the optimal behaviour of a system under a very general class of constraints. This field has been pioneered by the group of mathematicians led by Lev Pontryagin in the second half of the 50s and nowadays has countless applications to the real worlds (robotics, trains, aerospace, models for human behaviour, human vision, image reconstruction, quantum control, motion of self-propulsed micro-organism).
In this thesis we introduce a novel definition of curvature for an optimal control problem. In particular it works for any sub-Riemannian and sub-Finsler structure. Related problems, such as comparison theorems for sub-Riemannian manifolds, LQ optimal control problem and Popp's volume and are also investigated
Adjoint forms and algebraic families
Full text linkIn this thesis we study in details the theory of adjoint forms which was introduced by Collino and Pirola in the case of smooth curves and then generalized in higher dimension by Pirola and Zucconi. Useful generalizations are given, for example for Gorenstein curves, smooth projective hypersurfaces and fibrations over a smooth curve.
The main applications of this theory concern infinitesimal Torelli problems and criteria which ensure that a family of algebraic varieties of general type and with Albanese morphism of degree has birational fibers
Generalized adjoint forms on algebraic varieties
No full textWe prove a full generalization of the Castelnuovo’s free pencil trick. We show its analogies with Rizzi and Zucconi (Differential forms and quadrics of the canonical image. arXiv:1409.1826, Theorem 2.1.7); see also Pirola and Zucconi (J Algebraic Geom 12(3):535–572, Theorem 1.5.1). Moreover we find a new formulation of the Griffiths’s infinitesimal Torelli Theorem for smooth projective hypersurfaces using meromorphic 1-forms. © 2016 Fondazione Annali di Matematica Pura ed Applicata and Springer-Verlag Berlin Heidelber
Recent results on the essential self-adjointness of sub-Laplacians, with some remarks on the presence of characteristic points
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Italian Validation of the Touch Avoidance Measure and the Touch Avoidance Questionnaire
No full textSocial touch is essential in relationships and well-being, but the unique personal
experience of touch is not assessed and taken into account in health and social care
services. The pleasantness of gentle stroking is influenced by gender, toucher genre,
toucher familiarity, culture, and age. Moreover, pleasantness is influenced by touch
avoidance, the attitude toward interpersonal touch. The aim of this article is to present
the translation, adaptation, and validation in Italian of two scales to measure touch
avoidance. For translation and validation, we selected the most used scale, the Touch
Avoidance Measure (TAM) and a more recent scale, the Touch Avoidance Questionnaire
(TAQ). Confirmatory factor analyses reported good model fit for the TAM [comparative
fit index (CFI) = 0.947, Tucker–Lewis index (TLI) = 0.940, root-mean-square error of
approximation (RMSEA) = 0.065] and excellent model fit for the TAQ (CFI = 0.954,
TLI = 0.950, RMSEA = 0.058). Internal consistency was high for all subscales, except
the TAQ “Stranger” subscale. One-month test–retest reliability ranged from 0.67 to 0.90
for each subscale. Lastly, convergent validity between the TAM and TAQ was also found
to be high. We conclude that the TAM and TAQ can be used to assess touch avoidance
with Italian samples. The instrument can be used to support healthcare professionals
and to assess attitudes toward touch in individuals with interpersonal difficulties
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
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