The aim of this paper is to show how the spine of a PDE surface can be generated and how it can be used to efficiently parameterise a PDE surface. For the purpose of the work presented here an approximate analytic solution form for the chosen PDE is utilised. It is shown that the spine of the PDE surface is then computed as a by-product of this analytic solution. Furthermore, it is shown that a parameterisation can be introduced on the spine enabling intuitive manipulation of PDE surfaces.

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No / This report is concerned with fragmented skeletal remains dating to the Middle Bronze Age that were excavated in the 2001 campaign at Sidon, Lebanon. From 19 discrete burial units a total of 31 individuals were identifiedand assessed as to their biological characteristics. The majority of adults who could be sexed were male, many of them strongly built. The overall age distribution in this sample is characterised by a pattern commonly found in prehistoric assemblages, with high mortality during infancy and early childhood and a peak in adult mortality during early adulthood. There is a conspicuous occurrence of unusual dental traits. Jar burials, all found with remains of sub-adult individuals, represent a burial practice applied to children of a wide age range. Many burials are associated with faunal remains, mostly of sheep or goats, but also of large ungulates.

The aim of this study was to assess sensitivity of early life stage zebrafish to cadmium (Cd). Embryos and larva were exposed to Cd before the formation of skeletal elements. Exposure times were selected to determine whether Cd perturbed developmental processes that lead to skeletal deformities, and to characterize the types of skeletal deformities that occurred. Embryo/larva were exposed to 3μM, 10μM, 30μM, 100μM, 300μM, and 1000μM Cd at 12-36 hours post fertilization (hpf), 36-60hpf, 60-84hpf, and 144-168hpf in one series of experiments. This experiment was conducted at circumneutral pH. A second series of experiments with these same Cd concentrations were also conducted at pH 6 with embryo/larva exposed at 12-36hpf, 36-60hpf, and 60-84hpf. The fish that survived the exposures were raised for 40-60 days whereupon the surviving fish were overdosed with MS222, and X-rayed. The later early life stage fish were more sensitive to Cd toxicity; the chorion appeared to protect the earlier exposed embryos (zebrafish hatch 48-72hpf). Embryo/larva were more resistant to toxicity from dissolved Cd (pH 6) than particulate Cd (circumneutral pH); absence of functional gills during early life stages perhaps explained resistance to dissolved Cd. Notochord lesions (typically lethal within two weeks) occurred when embryos were exposed 12-36hpf. There was no evidence for sensitivity of early life stage zebrafish to Cd induced skeletal deformities that occurred within 40-60 days of Cd exposures. / Graduation date: 2004

SkePU (Skeleton Programming Framework for Multi-core CPU and Multi-GPU Systems) is a parallel computing framework developed by Johan Enmyren and Christoph Kessler at Linköpings Universitet. This C++ template library provides a simple and unified interface for specifying data-parallel computations with the help of skeletons and is targeted to multiple backends e.g. for a sequential CPU, parallel CPUs using MPI and OpenMP or GPUs using CUDA and OpenCL. SkePU is comprised of seven data-parallel skeletons and one task-parallel skeleton and these skeletons use two types of containers: vector and matrix to model real-life parallel applications. In this thesis, we address the extension of the SkePU framework by extending the matrix container (which stores 2-D data values) that can efficiently use the existing skeletons to develop parallel scientific applications on large-scale clusters using MPI. This piece of work focuses on the distribution of the matrix among the participating processes which after receiving their share of data can execute the application in parallel. This work covers all of the seven data-parallel skeletons. Each skeleton has been tested with a small application program. In addition to measurement of performance improvement from the application program’s execution time, we have also done a communication cost analysis for all skeletons with MPI using the LogGP model. In order to evaluate and test the operational efficiency of the extension, we have considered a PDE solver application. Through this application, we have demonstrated the performance gain and scalability of the extended framework. The performance improvement was more when computational load dominates the memory I/O operations. The results show that using the extension can serve as a viable approach while implementing real-life parallel applications on large-scale clusters.

The trend in computer architectures has for several years been heterogeneous systems consisting of a regular CPU and at least one additional, specialized processing unit, such as a GPU.The different characteristics of the processing units and the requirement of multiple tools and programming languages makes programming of such systems a challenging task. Although there exist tools for programming each processing unit, utilizing the full potential of a heterogeneous computer still requires specialized implementations involving multiple frameworks and hand-tuning of parameters.To fully exploit the performance of heterogeneous systems for a single computation, hybrid execution is needed, i.e. execution where the workload is distributed between multiple, heterogeneous processing units, working simultaneously on the computation. This thesis presents the implementation of a new hybrid execution backend in the algorithmic skeleton framework SkePU. The skeleton framework already gives programmers a user-friendly interface to algorithmic templates, executable on different hardware using OpenMP, CUDA and OpenCL. With this extension it is now also possible to divide the computational work of the skeletons between multiple processing units, such as between a CPU and a GPU. The results show an improvement in execution time with the hybrid execution implementation for all skeletons in SkePU. It is also shown that the new implementation results in a lower and more predictable execution time compared to a dynamic scheduling approach based on an earlier implementation of hybrid execution in SkePU.

L'analyse d'images est devenue ces dernières années une discipline de plus en plus riche de l'informatique. La topologie discrète propose un panel d'outils incontournables dans le traitement d'images, notamment grâce à l'outil du squelette, qui permet de simplifier des objets tout en conservant certaines informations intactes. Cette thèse étudie comment certains outils de la topologie discrète, notamment les squelettes, peuvent être utilisés pour le traitement d'images de matériaux.Le squelette d'un objet peut être vu comme une simplification d'un objet, possédant certaines caractéristiques identiques à celles de l'objet original. Il est alors possible d'étudier un squelette et de généraliser certains résultats à l'objet entier. Dans une première partie, nous proposons une nouvelle méthode pour conserver, dans un squelette, certaines caractéristiques géométriques de l'objet original (méthode nécessitant un paramètre de filtrage de la part de l'utilisateur) et obtenir ainsi un squelette possédant la même apparence que l'objet original. La seconde partie propose de ne plus travailler avec des objets constitués de voxels, mais avec des objets constitués de complexes cubiques. Dans ce nouveau cadre, nous proposons de nouveaux algorithmes de squelettisation, dont certains permettent de conserver certaines caractéristiques géométriques de l'objet de départ dans le squelette, de façon automatique (aucun paramètre de filtrage ne doit être donné par l'utilisateur). Nous montrerons ensuite comment un squelette, dans le cadre des complexes cubiques, peut être décomposé en différentes parties. Enfin, nous montrerons nos résultats sur différentes applications, allant de l'étude des matériaux à l'imagerie médicale / These last years, the domain of image analysis has drastically evolved. Digital topology offer a set of tools adapted to image analysis, especially the skeletonization process (also called homotopic thinning) which can simplify input data while keeping specific information untouched. In this thesis, we focus on how digital topology, especially skeletons, can help material image analysis.The goal of a skeletonization process is to remove unnecessary information from an input, and provide a simplified object, called the skeleton, having the same characteristics than the original data. It is then possible to perform some computations on the skeleton and generalise their results to the original data. In the first part of this thesis, we propose some new tools for preserving, during skeletonization, important geometrical features of the original data, and obtain a skeleton with the same visual appearance than the input.In the second part, we present the cubical complex framework, where objects are no more made only of voxels. We propose in this framework new skeletonization algorithms, some of them preserving automatically the visual aspect of the input during the thinning process (no filtering parameter from the user is required). We then show how a skeleton, in the cubical complexes framework, can be decomposed into basic parts, and we show some applications of these algorithms to material image analysis and medical image analysis

The aim of this thesis is to design main parts of the construction for concrete sports hall made from prefabricated elements. Designed elements are T-shaped prestressed roof truss, columns, slabs and continuous girders. This thesis contains engineering report, calculations and drawings of the designed parts.