Search results for "Geometric"
showing 10 items of 652 documents
Optimal Control of the Controlled Lotka-Volterra Equations with Applications - The Permanent Case
2022
In this article motivated by the control of complex microbiota in view to reduce the infection by a pathogenic agent, we introduce the theoretical frame from optimal control to analyze the problem. Two complementary approaches can be applied in the analysis: one is the so-called permanent case, where no digital constraints are concerning the control (taken as a measurable mapping) versus the sampled-data control case taking into account the logistic constraints, e.g. frequency of the medical interventions. The model is the n-dimensional Lotka-Volterra equation controlled using either probiotics or antibiotic agents or transplantation and bactericides. In the permanent case the Maximum princ…
COVARIANCE AND CORRELATION ESTIMATORS IN BIPARTITE SYSTEMS
2017
We present a weighted estimator of the covariance and correlation in bipartite complex systems with a double layer of heterogeneity. The advantage provided by the weighted estimators lies in the fact that the unweighted sample covariance and correlation can be shown to possess a bias. Indeed, such a bias affects real bipartite systems, and, for example, we report its effects on two empirical systems, one social and the other biological. On the contrary, our newly proposed weighted estimators remove the bias and are better suited to describe such systems.
On hyperbolic type involutions
2001
We give a bound on the number of hyperbolic knots which are double covered by a fixed (non hyperbolic) manifold in terms of the number of tori and of the invariants of the Seifert fibred pieces of its Jaco-Shalen-Johannson decomposition. We also investigate the problem of finding the non hyperbolic knots with the same double cover of a hyperbolic one and give several examples to illustrate the results.
A method to reduce the FP/imm number through CC and MLO views comparison in mammographic images
2008
In this paper we propose a method to reduce the FP/imm number through CC and MLO mammographic views comparison of the same patient. The proposed solution uses the symmetry properties of the breast to compute a geometric transformation that permits to represent the two images in comparable coordinates systems. Through this method, potential pathological ROIs of one of the projections are correlated with the ROIs in the second view. To show the effectiveness of the result we apply the method on a dataset composed of 112 couples of pathological images. Experiments shows that method enables a reduction by up to 700/0 of the FP/imm number detected after the classification step
Conversion d'un carreau de Bézier rationnel biquadratique en un carreau de cyclide de Dupin quartique
2006
Dupin cyclides were introduced in 1822 by the French mathematician C-P. Dupin. They are algebraic surfaces of degree 3 or 4. The set of geometric properties of these surfaces has encouraged an increasing interest in using them for geometric modeling. A couple of algorithmes is already developed to convert a Dupin cyclide patch into a rational biquadratic Bezier patch. In this paper, we consider the inverse problem: we investigate the conditions of convertibility of a Bezier patch into a Dupin cyclide one, and we present a conversion algorithm to compute the parameters of a Dupin cyclide with the boundary of the patch that corresponds to the given Bezier patch.
ANALISI ARCHEOMETRICHE DELLA CERAMICA A DECORAZIONE GEOMETRICA DIPINTA E A VERNICE NERA
2018
Di seguito vengono esposti i risultati derivanti dalla caratterizzazione petrografica e chimica di 20 reperti ceramici costituiti da scodelle, bacini, tazze, coppe, brocche a decorazione geometrica dipinta datati dalla fine del VII sec. alla metà del V sec. a.C. (campioni siglati da ER-1 a ER-10) e da coppe/skiphoi decorati a vernice nera (campioni siglati da ER-11 a ER-20), datati dalla fine del VI al V sec. a.C.. Tutti i campioni analizzati provengono dal contesto di fondazione delle mura arcaiche di Erice (TP). L’approccio metodologico ha previsto la caratterizzazione degli impasti ceramici in termini tessiturali (addensamento e distribuzione dimensionale degli inclusi, natura ed omogene…
Quantitative trait loci affecting the 3D skull shape and size in mouse and prioritization of candidate genes in-silico.
2015
13 pages; International audience; We describe the first application of high-resolution 3D micro-computed tomography, together with 3D landmarks and geometric morphometrics, to map QTL responsible for variation in skull shape and size using a backcross between C57BL/6J and A/J inbred strains. Using 433 animals, 53 3D landmarks, and 882 SNPs from autosomes, we identified seven QTL responsible for the skull size (SCS.qtl) and 30 QTL responsible for the skull shape (SSH.qtl). Size, sex, and direction-of-cross were all significant factors and included in the analysis as covariates. All autosomes harbored at least one SSH.qtl, sometimes up to three. Effect sizes of SSH.qtl appeared to be small, r…
Fourier series for elliptic integrals and some generalizations via hypergeometric series
2008
Fourier series are derived for generalizations of the three canonical Legendre incomplete elliptic integrals using a hypergeometric series approach. The Fourier series for the incomplete Epstein–Hubbell integrals are obtained as special cases of the generalization of the Legendre integrals of the first and second kinds. The Fourier series for the integrals of the first and second kinds, and those for the Epstein–Hubbell integrals, were obtained recently using a different approach, but the series obtained for the generalization of the incomplete integral of the third kind is new. All cases of the integral of the third kind are given, with the modulus and the parameter being complex variables…
Indefinite integrals of incomplete elliptic integrals from Jacobi elliptic functions
2017
Integration formulas are derived for the three canonical Legendre elliptic integrals. These formulas are obtained from the differential equations satified by these elliptic integrals when the indep...
Il portico meridionale della Cattedrale di Palermo : corrispondenze geometriche tra decorazione e architettura
2020
Negli ultimi venti anni si sono diffusi, prima nei centri di ricerca e poi in modo più capillare, scanner tridimensionali e procedure fotogrammetriche capaci di generare simulacri digitali tridimensionali di manufatti. L’uso di strumenti digitali per il rilievo e la rappresentazione di opere d’arte e di architettura ha profondamente trasformato procedure e metodi storicamente consolidati e al contempo ha offerto nuove possibilità di indagine. La possibilità di misurare e sezionare, nello spazio virtuale dei software di rappresentazione, avatar digitali che documentano in modo dettagliato la morfologia e le qualità cromatiche di un artefatto, ha aperto nuove prospettive alle indagini sulle m…