1,721,664 research outputs found
Visione delle macchine: Una sfida anche per i matematici
No full textLa visione delle macchine, o visione artificiale, richiede l'ausilio di strumenti matematici già esistenti o ancora da inventare. Sono esaminati diversi aspetti di questa interazione fra discipline
Crystallisations of 2-fold branched coverings of 𝑆³
No full textWe describe the construction of a crystallisation of a 2-fold cyclic covering space of
S
3
{S^3}
branched over a link, from a bridge-presentation of the branch set.</p
Size functions for the morphological analysis of melanocytic lesions
No full textSize Functions and Support Vector Machines are used to implement a new automatic classifier of melanocytic lesions. This is mainly based on a qualitative assessment of asymmetry, performed by halving images by several lines through the center of mass, and comparing the two halves in terms of color, mass distribution, and boundary. The program is used, at clinical level, with two thresholds, so that comparison of the two outputs produces a report of low-middle-high risk. Experimental results on 977 images, with cross-validation, are reported. © 2010 M. Ferri and I. Stanganelli
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
Crystallisation moves
No full textA crystallisation of a closed PL-manifold is an edgecoloured graph, which represents it via a contracted triangulation. Any two crystallisations of the same manifoldare proved to be joined by a finite sequence of moves, two alternative sets of which are defined. A further move for dimension 3 is introduced. © 1982, University of California, Berkeley. All Rights Reserved
On the genus of 4-dimensional products of manifolds
No full textWe determine bounds for the regular genus of any 4-manifold, which is a product of {Mathematical expression} by a closed 3-manifold, or a product of two closed surfaces. This is done by an explicit construction of a graph representing the manifold, and by finding a minimal regular imbedding of it. © 1982 D. Reidel Publishing Company
The only genus zero n-manifold is sn
No full textAll n-manifolds of regular genus zero, i.e. admitting a crystallization which regularly imbeds into S2, are proved to be homeomorphic to Sn. A conjecture implying the Poincaré Conjecture in dimension four is also formulated. Sunto. Si dimostra che tutte le n-varietà di genere regolare zero, cioè aventi una cristallizzazione che si immerge regolarmente in S2, sono omeomorfe a Sn. Si formula anche una congettura che implica quella di Poincaré in dimensione quattro. © 1982 American Mathematical Society
Multiple residues in dimension three
No full textEdge-coloured graphs can be seen as schemes of pseudosimplicial complexes. Standard manipulation of such graphs may introduce unwanted singularities in the represented complexes. Here, a technique of elimination for a large class of singularities in four-colored graphs (hence in 3-dimensional complexes) is presented. © 1988
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