1,721,004 research outputs found
Arcs and blocking sets in symmetric designs
No full textThe notion of ovals, blocking sets and their connections have been of interest in the study of finite projective planes. The aim of this paper is to generalize these notions and the most considerable theorems in the case of symmetric designs
Esploriamo la geometria combinatoria
No full textSome of the fundamental ideas about combinatorial geometry are presented. We start with the study of some affine, finite planes, to then come to that of the Graeco-Latin squares. Some very interesting problems are here emphasized, like Euler's one of the 36 officers or, in more recent times, Kirkman's one (19th century) of the 15 schoolgirls. We end the paper with the analysis of some aspect of cryptography
DTM to NURBS-A parametric approach to landscape modeling
No full textThe aim of this research work is the automated generation of a three-dimensional Nurbs model from a series of data on a territorial scale. The difficulty of working with this type of procedure is the sectorialisation of technical skills among the technicians who deal with design at the architectural scale and those who works at territorial scale. The undertaken methodology is to establish a workflow that can export data from a GIS tool and import it into a three-dimensional modeler. To do this you need an intermediate tool, a parametric software. The explained procedure aims to have maximum freedom of processing of model geometries; therefore, the geometry has been based on Nurbs mathematical models. The case study where the methodology of this research has been applied is the territory of Ortona, Italy, the Adriatic coast. Starting from the cartographic data of the Abruzzo Region, the three-dimensional model has been realized as in the forecast. This working methodology ensures efficient results with a low amount of human iteration to generate the final model. Some of the limitations of the procedure have been explained in detail, mainly due to the structure of the used components
On sets of fixed parity in Steiner systems
No full textA set H of points in a Steiner system S(t,k,v) is called of even (odd) type if the intersection size is even (odd) with any block. In this paper we give conditions for the non-existence of such sets and examples
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