Search results for "Polygon"

Ecological variation between marginal and central populations of Potamogeton polygonifolius, a rare and endangered species in Central Europe

2012

Abstract The present study is focused on Potamogeton polygonifolius – the species considered to be endangered in Germany, the Czech Republic, Poland and Switzerland. Field studies were carried out in Lower Silesia and Lusatia in southwestern Poland in order to verify the present state of the marginal populations of P. polygonifolius, to determine the habitat preferences of the species in the study area, to compare the ecological data between marginal and central populations and finally to recognise the factors constraining the easternmost limit of the P. polygonifolius. In total, 18 populations were examined, and 11 releves were collected. The releves gathered were compared with 95 releves …

ON SOME GENERALIZATION OF SMOOTHING PROBLEMS

2015

The paper deals with the generalized smoothing problem in abstract Hilbert spaces. This generalized problem involves particular cases such as the interpolating problem, the smoothing problem with weights, the smoothing problem with obstacles, the problem on splines in convex sets and others. The theorem on the existence and characterization of a solution of the generalized problem is proved. It is shown how the theorem gives already known theorems in special cases as well as some new results.

FROM SFM TO 3D PRINT: AUTOMATED WORKFLOW ADDRESSED TO PRACTITIONER AIMED AT THE CONSERVATION AND RESTAURATION

2017

Abstract. In In the last years there has been an increasing use of digital techniques for conservation and restoration purposes. Among these, a very dominant rule is played by the use of digital photogrammetry packages (Agisoft Photoscan, 3D Zephir) which allow to obtain in few steps 3D textured models of real objects. Combined with digital documentation technologies digital fabrication technologies can be employed in a variety of ways to assist in heritage documentation, conservation and dissemination. This paper will give to practitioners an overview on the state of the art available technologies and a feasible workflow for optimizing point cloud and polygon mesh datasets for the purpose …

Enhanced chain dynamics in loop-sorting-systems by means of layout optimization and a kinematic model of the polygon action

2012

Published version of an article in the journal: Structural and Multidisciplinary Optimization. Also available from the publisher at: http://dx.doi.org/10.1007/s00158-011-0743-7 Poor dynamics owing to polygon action is a known concern in mechanical applications of closed articulated chains. In this paper a kinematic model of the polygon action in large chains of loop-sorting-systems is proposed. Through optimization techniques the chain dynamics is improved by minimizing the polygon action using a parametric model of the track layout as design variables. Three formulations of the kinematic polygon action are tested on an average sized planer tracks layout to find a superior model. Verificati…

Polygonal mesh segmentation by surface curvature diffusion.

2011

From the fourteenth century to Cabrì: convuleted constructions of star polygons

2014

Shape identification in inverse medium scattering problems with a single far-field pattern

2016

Consider time-harmonic acoustic scattering from a bounded penetrable obstacle $D\subset {\mathbb R}^N$ embedded in a homogeneous background medium. The index of refraction characterizing the material inside $D$ is supposed to be Holder continuous near the corners. If $D\subset {\mathbb R}^2$ is a convex polygon, we prove that its shape and location can be uniquely determined by the far-field pattern incited by a single incident wave at a fixed frequency. In dimensions $N \geq 3$, the uniqueness applies to penetrable scatterers of rectangular type with additional assumptions on the smoothness of the contrast. Our arguments are motivated by recent studies on the absence of nonscattering waven…

Splines in convex sets under constraints of two‐sided inequality type in a hyperplane

2008

The problem of minimization of a smoothing functional under inequality constraints is considered in a hyperplane. The conditions of the existence of a solution are obtained and some properties of this solution are investigated. It is proved that the solution is a spline. The method for its construction is suggested. First Published Online: 14 Oct 2010

I poligoni stellati: origini storiche ed implicazioni didattiche

2019

The genesis of mathematical concepts in the evolutionary line of human thought in the long story and the genesis in individual optics possess evident analogies. Starting from this assumption, we describe an activity presented to 15-year-old students; the aim was to consolidate fundamental concepts of Euclidean geometry related to regular polygons. The experimentation has used a didactic approach based on the historical evolution of the formal definition of regular star polygon through the centuries. The activity and the results obtained in terms of internalization of the concepts in the students are showed.

Parallel Genetic Solution for Multiobjective MDO

1997

Publisher Summary This chapter reviews a multiobjective, multidisciplinary design optimization of two-dimensional airfoil designs. The control points on leading and trailing edges remain fixed, and the y-coordinates of the other control points are allowed to change during the optimization process. The grid for the Euler solver depends continuously and smoothly on the design parameters. The number of nodes and elements in the mesh might vary according to design because the meshes for the Helmholtz solver are done using the local fitting. The computations are made on an IBM SP2 parallel computer using high-performance switch and the MPICH message-passing library. As gradients are not required…