Duotone Surfaces: Division of a Closed Surface into Exactly Two Regions

In this thesis work, our main motivation is to create computer aided art work which can eventually transform into a sculpting tool. The work was inspired after Taubin’s work on constructing Hamiltonian triangle strips on quadrilateral meshes. We present an algorithm that can divide a closed 2-manifold surface into exactly two regions, bounded from each other by a single continuous curve. We show that this kind of surface division is possible only if the mesh approximation of a given object is a two colorable quadrilateral mesh. For such a quadrilateral mesh, appropriate texturing of the faces of the mesh using a pair of Truchet tiles will give us a Duotone Surface. Catmull-Clark subdivision can convert any given mesh with arbitrary sided polygons into a two colorable quadrilateral mesh. Using such vertex insertion schemes, we modify the mesh and classify the vertices of the new mesh into two sets. By appropriately texturing each face of the mesh such that the color of the vertices of the face match with the colored regions of the corresponding Truchet tile, we can get a continuous curve that splits the surface of the mesh into two regions. Now, coloring the thus obtained two regions with two different colors gives us a Duotone Surface

TECNICHE DI AGGREGAZIONE IN SISTEMI P2P: WAVELET E BLOOM FILTERS

La tesi presenta l'analisi di due tecniche di aggregazione utilizzate per la rappresentazione e la ricerca di risorse in sistemi P2P. Il candidato ha realizzato i moduli che implementano Bloom Filters e Wavelet integrandoli in un framework che supporta range query multidimensionali. La tesi presenta un insieme di risultati sperimentali che presentano la validità dell'approccio

Analisi e sperimentazione di curve space-filling per range query multiattributo in sistemi P2P

La tesi presenta una vasta rassegna delle principali proposte per il supporto di range query multiattributo in sistemi P2P, con particolare attenzione alle proposte basate sull'uso di curve space-filling. La tesi propone inoltre un supporto che utilizza la Z-Order curve per linearizzare lo spazio di una query n-dimensionale e ne valuta le prestazioni

Murray polygons as a tool in image processing

This thesis reports on some applications of murray polygons, which are a generalization of space filling curves and of Peano polygons in particular, to process digital image data. Murray techniques have been used on 2-dimensional and 3-dimensional images, which are in cartesian/polar co-ordinates. Attempts have been made to resolve many associated aspects of image processing, such as connected components labelling, hidden surface removal, scaling, shading, set operations, smoothing, superimposition of images, and scan conversion. Initially different techniques which involve quadtree, octree, and linear run length encoding, for processing images are reviewed. Several image processing problems which are solved using different techniques are described in detail. The steps of the development from Peano polygons via multiple radix arithmetic to murray polygons is described. The outline of a software implementation of the basic and fast algorithms are given and some hints for a hardware implementation are described The application of murray polygons to scan arbitrary images is explained. The use of murray run length encodings to resolve some image processing problems is described. The problem of finding connected components, scaling an image, hidden surface removal, shading, set operations, superimposition of images, and scan conversion are discussed. Most of the operations described in this work are on murray run lengths. Some operations on the images themselves are explained. The results obtained by using murray scan techniques are compared with those obtained by using standard methods such as linear scans, quadtrees, and octrees. All the algorithms obtained using murray scan techniques are finally presented in a menu format work bench. Algorithms are coded in PS-algol and the C language

Studies related to the process of program development

The submitted work consists of a collection of publications arising from research carried out at Rhodes University (1970-1980) and at Heriot-Watt University (1980-1992). The theme of this research is the process of program development, i.e. the process of creating a computer program to solve some particular problem. The papers presented cover a number of different topics which relate to this process, viz. (a) Programming methodology programming. (b) Properties of programming languages. aspects of structured. (c) Formal specification of programming languages. (d) Compiler techniques. (e) Declarative programming languages. (f) Program development aids. (g) Automatic program generation. (h) Databases. (i) Algorithms and applications

On the generation and use of space-filling curves

A recent note describes elegant algorithms for drawing certain space-filling curves. These seem to be an improvement upon recursive algorithms described earlier, which are in turn a very considerable improvement on non-recursive algorithms for the same problem. This note points out that such elegant algorithms have been known for some time; indeed they form the basis of a series of experimental graphics languages which have been designed expressly to permit artists to create beautiful and intricate pictures without resorting to tedious specification of each individual picture element. Moreover, contrary to popular belief, recursive space-filling curves have applications apart from producing pretty pictures: we briefly describe one of these and point out an intriguing similarity between the two-dimensional fast Fourier transform decomposition of a plane and the order of points visited by a Peano curve.We are currently acquiring citations for the work deposited into this collection. We recognize the distribution rights of this item may have been assigned to another entity, other than the author(s) of the work.If you can provide the citation for this work or you think you own the distribution rights to this work please contact the Institutional Repository Administrator at [email protected]

ON THE GENERATION AND USE OF SPACE-FILLING CURVES

A recent note describes elegant algorithms for drawing certain space-filling curves. These seem to be an improvement upon recursive algorithms described earlier, which are in turn a very considerable improvement on non-recursive algorithms for the same problem. This note points out that such elegant algorithms have been known for some time; indeed they form the basis of a series of experimental graphics languages which have been designed expressly to permit artists to create beautiful and intricate pictures without resorting to tedious specification of each individual picture element. Moreover, contrary to popular belief, recursive space-filling curves have applications apart from producing pretty pictures: we briefly describe one of these and point out an intriguing similarity between the two-dimensional fast Fourier transform decomposition of a plane and the order of points visited by a Peano curve.We are currently acquiring citations for the work deposited into this collection. We recognize the distribution rights of this item may have been assigned to another entity, other than the author(s) of the work.If you can provide the citation for this work or you think you own the distribution rights to this work please contact the Institutional Repository Administrator at [email protected]