Search results for " Geometry."
showing 10 items of 2189 documents
Sparse relative risk survival modelling
2016
Cancer survival is thought to closed linked to the genimic constitution of the tumour. Discovering such signatures will be useful in the diagnosis of the patient and may be used for treatment decisions and perhaps even the development of new treatments. However, genomic data are typically noisy and high-dimensional, often outstripping the number included in the study. Regularized survival models have been proposed to deal with such scenary. These methods typically induce sparsity by means of a coincidental match of the geometry of the convex likelihood and (near) non-convex regularizer.
Digital and Interactive Learning and Teaching Methods in Descriptive Geometry
2013
Abstract During the course of “Fundamentals and applications of Science of Representation - Geometric drawing” (held at the Faculty of Engineering at the University of Palermo) we successfully tested the adoption of informatics tools to enhance the comprehension and the critical analysis of complex figures in the geometrical space. The peculiarity in the teaching methodology was the adoption of interactive software products (Cabri Geometre and GeoGebra concerning dynamic and geometrical constructions; the well-known Rhinoceros plug-in, Grasshopper, about generating algorithms; Linceo regarding implementing the graphic display of complex solids in augmented reality). According to our experie…
An unbounded family of log Calabi–Yau pairs
2016
We give an explicit example of log Calabi-Yau pairs that are log canonical and have a linearly decreasing Euler characteristic. This is constructed in terms of a degree two covering of a sequence of blow ups of three dimensional projective bundles over the Segre-Hirzebruch surfaces ${\mathbb F}_n$ for every positive integer $n$ big enough.
Some Considerations on 3-D and 2-D Numerical Models for the Assessment of the Stability of Underground Caves
2014
The application of numerical modeling to the analysis of the stability of both natural and man-made underground caves is rapidly increasing due to the availability of powerful numerical codes, that can account for either continuum or discontinuum behavior of the rock masses. Numerical methods allow to overcome traditional methods for cave stability analysis that assume too simplified geometrical, geological and geomechanical conditions. Further, they are also able to assess the potential failure mechanisms of underground systems. On the other hand, the application of numerical methods requires availability of a detailed geo-structural survey of the cave, as well as a proper geomechanical ch…
Geometric and morphologic evolution of normal fault planes and traces from 2D to 4D data
2003
Abstract The detailed 3D geometry of normal fault planes is described and analysed using datasets from outcrop studies (2D), seismic surveys (3D) and analogue models (4D). Different geometric configurations of simple isolated normal faults are studied by reference to processes of normal fault propagation. When a normal fault propagates without interacting with other fault zones, the entire border of the principal plane displays characteristic connected secondary structures. These secondary structures cause bifurcations of the principal fault terminations. The along-strike terminations of the principal plane display typical bifurcation configurations (‘ear geometry‘). The orientation of the …
From Dupin cyclides to scaled cyclides
2003
Dupin cyclides are algebraic surfaces introduced for the first time in 1822 by the French mathematician Pierre-Charles Dupin. They have a low algebraic degree and have been proposed as a solution to a variety of geometric modeling problems. The circular curvature line’s property facilitates the construction of the cyclide (or the portion of a cyclide) that blends two circular quadric primitives. In this context of blending, the only drawback of cyclides is that they are not suitable for the blending of elliptic quadric primitives. This problem requires the use of non circular curvature blending surfaces. In this paper, we present another formulation of cyclides: Scaled cyclides. A scaled cy…
THE GEOMETRY THROUGH THE BODY: DOING, ACTING, THINKING
2016
The geometry has been for more than two millennia one of the most important fields of knowledge of mathematics, identifying with it for a long time. In education, the relationship between the geometry and the physical world has always been considered one of the main elements for the acquisition of specific skills and competences. In the teaching-learning processes the thinking and the interconnection between doing, acting, thinking is therefore crucial. Teaching through the body may prove effective for teaching mathematics which, very often, is hard to be learned because of difficulties that the child encounters in assimilating mathematical symbolism and, after, applying it to real life and…
Diorganotin(IV) complexes ofD-galacturonic acid: solid-state and solution-phase structural study
2003
Three diorganotin(IV) complexes of D-galacturonic acid (H2GalA; R = Me, n-Bu, Ph), two of which are new derivatives (R = Me, Ph), have been synthesized and their solid-state and solution-phase investigated by IR, Mossbauer, 1H, 13C and 119Sn NMR spectroscopy. The FTIR data suggest that H2GalA, in the dialkyltin derivatives, behaves as a dianionic ligand, coordinating the tin(IV) atom through an ester-type carboxylate and deprotonated alcoholic hydroxo groups, whereas a bridging carboxylate occurs in the diphenyltin(IV) complex. Octahedral and trigonal bipyramidal local geometries on tin(IV) atoms are proposed for dialkyltin(IV)GalA and diphenyltin(IV)GalA complexes respectively on the basis…
El teorema de Pitàgores en segon d’ESO
2012
El teorema de Pitàgores és un contingut fonamental en l’assignatura de matemàtiques en el currículum d’Educació Secundària. Per tal de conèixer els continguts concrets que pertoquen a este curs, analitzem el que s’establix per Reial Decret al currículum oficial de l’Estat i al de la Comunitat Valenciana. Tindrem també en compte els continguts dels cursos anteriors i posteriors per tal d’evitar repeticions o insuficiències en la matèria. En el primer curs d’ESO s’estudia la fórmula i s’utilitza per a calcular el valor d’un costat d’un triangle rectangle coneguts els altres dos. En segon es demostra esta fórmula i s’utilitza per a determinar l’àrea de polígons; determinar si un triangle és re…
Reasons of irregularity of seed's distribution in the divider heads of air-seeders
2017
ISBN : 978-3-18-092300-0; International audience; Modern seeding equipment must allow to cultivate sizeable areas efficiently and finalize the seeding in a short amount of time. Air-seeder is a solution for a fast seeding: seeds are conveyed from the high-capacity seed hopper to the coulter-bar by an air-stream. Taking into account the complexity of this type of seed drills, they stay little-studied. Few developments have been done on divider headers responsible of distribution accuracy. This paper deals with a study on the influence of divider head geometry and functioning conditions on the seed's distribution accuracy. Moreover, observation of the seed's behaviour is done using a high-spe…