Search results for "DIMENSION"

Classification of cat ganglion retinal cells and implications for shape-function relationship

2002

This article presents a quantitative approach to ganglion cell classification by considering combinations of several geometrical features including fractal dimension, symmetry, diameter, eccentricity and convex hull. Special attention is given to moment and symmetry-based features. Several combinations of such features are fed to two clustering methods (Ward's hierarchical scheme and K-Means) and the respectively obtained classifications are compared. The results indicate the superiority of some features, also suggesting possible biological implications.

The project scheduling polyhedron: Dimension, facets and lifting theorems

1993

Abstract The Project scheduling with resource constraints can be formulated as follows: given a graph G with node set N, a set H of directed arcs corresponding to precedence relations, and a set H′ of disjunctive arcs reflecting the resource incompatibilities, find among the subsets of H′ satisfying the resource constraints the set S that minimizes the longest path in graph (N, H ∪ S). We define the project scheduling polyhedron Qs as the convex hull of the feasible solutions. We investigate several classes of inequalities with respect to their facet-defining properties for the associated polyhedron. The dimension of Qs is calculated and several inequalities are shown to define facets. For …

Graph cut-based method for segmenting the left ventricle from MRI or echocardiographic images

2017

International audience; In this paper, we present a fast and interactive graph cut method for 3D segmentation of the endocardial wall of the left ventricle (LV) adapted to work on two of the most widely used modalities: magnetic resonance imaging (MRI) and echocardiography. Our method accounts for the fundamentally different nature of both modalities: 3D echocardiographic images have a low contrast, a poor signal-to-noise ratio and frequent signal drop, while MR images are more detailed but also cluttered and contain highly anisotropic voxels. The main characteristic of our method is to work in a 3D Bezier coordinate system instead of the original Euclidean space. This comes with several ad…

Shape-Based Features for Cat Ganglion Retinal Cells Classification

2002

This article presents a quantitative and objective approach to cat ganglion cell characterization and classification. The combination of several biologically relevant features such as diameter, eccentricity, fractal dimension, influence histogram, influence area, convex hull area, and convex hull diameter are derived from geometrical transforms and then processed by three different clustering methods (Ward’s hierarchical scheme, K-means and genetic algorithm), whose results are then combined by a voting strategy. These experiments indicate the superiority of some features and also suggest some possible biological implications.

Convexities and optimal transport problems on the Wiener space

2013

The aim of this PhD is to study the optimal transportation theory in some abstract Wiener space. You can find the results in four main parts and they are aboutThe convexity of the relative entropy. We will extend the well known results in finite dimension to the Wiener space, endowed with the uniform norm. To be precise the relative entropy is (at least weakly) geodesically 1-convex in the sense of the optimal transportation in the Wiener space.The measures with logarithmic concave density. The first important result consists in showing that the Harnack inequality holds for the semi-group induced by such a measure in the Wiener space. The second one provides us a finite dimensional and dime…

The implications of the local context in global virtual education

2012

<input id="gwProxy" type="hidden" /><input id="jsProxy" onclick="if(typeof(jsCall)=='function'){jsCall();}else{setTimeout('jsCall()',500);}" type="hidden" /><p>This paper investigates how features in students’ everyday life influence their participation in online global collaboration, and it suggests that students’ local context should be recognised as a significant part of their educational space. In this exploratory case study of students engaged in a global online master’s programme, the discussion is organised under three main headings: the social, material, and cultural dimensions of students’ daily life. The paper shows how the influence of the students’ local contex…

C−C Cross-Couplings from a Cyclometalated Au(III) C∧ N Complex: Mechanistic Insights and Synthetic Developments

2021

Abstract In recent years, the reactivity of gold complexes was shown to extend well beyond π‐activation and to hold promises to achieve selective cross‐couplings in several C−C and C−E (E=heteroatom) bond forming reactions. Here, with the aim of exploiting new organometallic species for cross‐coupling reactions, we report on the Au(III)‐mediated C(sp2)−C(sp) occurring upon reaction of the cyclometalated complex [Au(CCH2N)Cl2] (1, CCH2N=2‐benzylpyridine) with AgPhCC. The reaction progress has been monitored by NMR spectroscopy, demonstrating the involvement of a number of key intermediates, whose structures have been unambiguously ascertained through 1D and 2D NMR analyses (1H, 13C, 1H‐1H CO…

Cor triatriatum dexter assessed by three-dimensional echocardiography reconstruction in a female adult patient.

2009

Steroidal saponins from the aerial parts of Cordyline fruticosa L. var. strawberries.

2019

A new sulfated steroidal derivative (fruticogenin A: 1-sulfo-australigenin-3-sodium sulphate, 1) and three new steroidal saponins named fruticoside K (3-sulfo-spirostan-25(27)-ene-1β,3β-diol-1-O-[α-L-rhamnopyranosyl-(1 → 4)-β-D-fucopyranoside], 2), fruticoside L (3-sulfo-spirostan-25(27)-ene-1β,3β,6α-triol-1-O-[α-L-rhamnopyranosyl-(1 → 4)-β-D-fucopyranoside], 3) and fruticoside M (spirostan-25(27)-ene-1β,3α-diol-1-O-[α-L-rhamnopyranosyl-(1 → 2)-α-L-rhamnopyranoside], 4) were isolated from the aerial parts of Cordyline fruticosa L. var. strawberries. Their structures were established on the basis of 1D and 2D NMR data, mass spectrometry and chemical methods. Compounds 2 and 4 exhibited weak …

Anatomical variants and anomalies of the coronary tree studied with MDCT coronary angiography

2010

Le anomalie delle arterie coronariche sono presenti alla nascita nella maggior parte dei casi asintomatiche ma possono manifestarsi con sintomatologia severa quale angina pectoris o addirittura l’arresto cardiaco. L’angiografia coronarica mediante tomografia computerizzata multistrato (TCMS) permette, tramite ricostruzioni multiplanari secondo piani curvilinei e riformattazioni 3D, la visualizzazione dell’albero coronarico e delle sue varianti ed anomalie in maniera non invasiva, fornendo migliore e più accurata alternativa alla angiografia coronarica (AC). Lo scopo di questo pictorial consiste nella descrizione mediante immagini TCMS con ricostruzioni multiplanari e 3D delle principali var…