Made available in DSpace on 2014-12-17T14:54:53Z (GMT). No. of bitstreams: 1 MarlosAMSO.pdf: 1784342 bytes, checksum: 36e985b587c52304548da7b98cad94f7 (MD5) Previous issue date: 2010-01-15 / Internet applications such as media streaming, collaborative computing and massive multiplayer are on the rise,. This leads to the need for multicast communication, but unfortunately group communications support based on IP multicast has not been widely adopted due to a combination of technical and non-technical problems. Therefore, a number of different application-layer multicast schemes have been proposed in recent literature to overcome the drawbacks. In addition, these applications often behave as both providers and clients of services, being called peer-topeer applications, and where participants come and go very dynamically. Thus, servercentric architectures for membership management have well-known problems related to scalability and fault-tolerance, and even peer-to-peer traditional solutions need to have some mechanism that takes into account member's volatility. The idea of location awareness distributes the participants in the overlay network according to their proximity in the underlying network allowing a better performance. Given this context, this thesis proposes an application layer multicast protocol, called LAALM, which takes into account the actual network topology in the assembly process of the overlay network. The membership algorithm uses a new metric, IPXY, to provide location awareness through the processing of local information, and it was implemented using a distributed shared and bi-directional tree. The algorithm also has a sub-optimal heuristic to minimize the cost of membership process. The protocol has been evaluated in two ways. First, through an own simulator developed in this work, where we evaluated the quality of distribution tree by metrics such as outdegree and path length. Second, reallife scenarios were built in the ns-3 network simulator where we evaluated the network protocol performance by metrics such as stress, stretch, time to first packet and reconfiguration group time / Atualmente aplica??es em grupo na Internet est?o em ascens?o, como por exemplo transmiss?o de ?udio e v?deo, computa??o colaborativa e jogos com m?ltiplos participantes. Isso leva ? necessidade de comunica??o multicast, mas infelizmente o suporte a este tipo de servi?o n?o est? amplamente dispon?vel pela camada de rede. Por isso, no atual est?gio tecnol?gico surgiram solu??es de protocolos multicast implementados na camada de aplica??o para suprir tal defici?ncia. Al?m disso, estas aplica??es muitas vezes se apresentam simultaneamente como provedores e clientes dos servi?os utilizados, caracterizando-as como aplica??es denominadas peer-to-peer, possuindo caracter?sticas din?micas, onde os participantes podem entrar e sair de um grupo com uma freq??ncia muito alta. Assim, algoritmos centralizados de ger?ncia de grupo n?o apresentam bom desempenho para essa classe de aplica??es, e mesmo as solu??es peer-to-peer tradicionais necessitam ter algum mecanismo que leve em considera??o essa volatilidade. A id?ia de consci?ncia de localiza??o permite distribuir os participantes na rede virtual de acordo com a sua proximidade na rede f?sica, permitindo um bom desempenho nas opera??es de gerenciamento do grupo. Diante deste contexto, nesta tese ? proposto um protocolo de comunica??o multicast na camada de aplica??o, chamado LAALM, que leva em considera??o a topologia da rede real no processo de montagem da rede virtual, utilizando uma nova m?trica denominada IPXY para prover a consci?ncia de localiza??o, atrav?s do processamento de informa??es locais. O LAALM foi implementado utilizando uma ?rvore distribu?da compartilhada e bi-direcional, possuindo uma heur?stica sub-?tima para o processo de inclus?o de novos participantes que visa minimizar o custo de constru??o da ?rvore de distribui??o de dados. A avalia??o do protocolo foi realizada de duas formas distintas: i) atrav?s de um simulador pr?prio onde se procurou avaliar a qualidade de constru??o da ?rvore de distribui??o gerada, avaliando-se m?tricas como o n?mero de filhos por cada n? e a dist?ncia final entre os n?s; ii) atrav?s de cen?rios real?sticos constru?dos no simulador de redes ns-3, onde foi avaliado o desempenho do protocolo atrav?s de m?tricas como stress, stretch e tempos de associa??o e reconfigura??o dos grupos

La quête de performance a été une constante à travers l’histoire des systèmes informatiques. Il y a plus d’une décennie maintenant, le modèle de traitement séquentiel montrait ses premiers signes d’épuisement pour satisfaire les exigences de performance. Les barrières du calcul séquentiel ont poussé à un changement de paradigme et ont établi le traitement parallèle comme standard dans les systèmes informatiques modernes. Avec l’adoption généralisée d’ordinateurs parallèles, de nombreux algorithmes et applications ont été développés pour s’adapter à ces nouvelles architectures. Cependant, dans des applications non conventionnelles, avec des exigences d’interactivité et de temps réel, la parallélisation efficace est encore un défi majeur. L’exigence de performance en temps réel apparaît, par exemple, dans les simulations interactives où le système doit prendre en compte l’entrée de l’utilisateur dans une itération de calcul de la boucle de simulation. Le même type de contrainte apparaît dans les applications d’analyse de données en continu. Par exemple, lorsque des donnes issues de capteurs de trafic ou de messages de réseaux sociaux sont produites en flux continu, le système d’analyse doit être capable de traiter ces données à la volée rapidement sur ce flux tout en conservant un budget de mémoire contrôlé La caractéristique dynamique des données soulève plusieurs problèmes de performance tel que la décomposition du problème pour le traitement en parallèle et la maintenance de la localité mémoire pour une utilisation efficace du cache. Les optimisations classiques qui reposent sur des modèles pré-calculés ou sur l’indexation statique des données ne conduisent pas aux performances souhaitées. Dans cette thèse, nous abordons les problèmes dépendants de données sur deux applications différentes : la première dans le domaine de la simulation physique interactive et la seconde sur l’analyse des données en continu. Pour le problème de simulation, nous présentons un algorithme GPU parallèle pour calculer les multiples plus courts chemins et des diagrammes de Voronoi sur un graphe en forme de grille. Pour le problème d’analyse de données en continu, nous présentons une structure de données parallélisable, basée sur des Packed Memory Arrays, pour indexer des données dynamiques géo-référencées tout en conservant une bonne localité de mémoire. / A busca por desempenho tem sido uma constante na história dos sistemas computacionais. Ha mais de uma década, o modelo de processamento sequencial já mostrava seus primeiro sinais de exaustão pare suprir a crescente exigência por performance. Houveram "barreiras"para a computação sequencial que levaram a uma mudança de paradigma e estabeleceram o processamento paralelo como padrão nos sistemas computacionais modernos. Com a adoção generalizada de computadores paralelos, novos algoritmos foram desenvolvidos e aplicações reprojetadas para se adequar às características dessas novas arquiteturas. No entanto, em aplicações menos convencionais, com características de interatividade e tempo real, alcançar paralelizações eficientes ainda representa um grande desafio. O requisito por desempenho de tempo real apresenta-se, por exemplo, em simulações interativas onde o sistema deve ser capaz de reagir às entradas do usuário dentro do tempo de uma iteração da simulação. O mesmo tipo de exigência aparece em aplicações de monitoramento de fluxos contínuos de dados (streams). Por exemplo, quando dados provenientes de sensores de tráfego ou postagens em redes sociais são produzidos em fluxo contínuo, o sistema de análise on-line deve ser capaz de processar essas informações em tempo real e ao mesmo tempo manter um consumo de memória controlada A natureza dinâmica desses dados traz diversos problemas de performance, tais como a decomposição do problema para processamento em paralelo e a manutenção da localidade de dados para uma utilização eficiente da memória cache. As estratégias de otimização tradicionais, que dependem de modelos pré-computados ou de índices estáticos sobre os dados, não atendem às exigências de performance necessárias nesses cenários. Nesta tese, abordamos os problemas dependentes de dados em dois contextos diferentes: um na área de simulações baseada em física e outro em análise de dados em fluxo contínuo. Para o problema de simulação, apresentamos um algoritmo paralelo, em GPU, para computar múltiplos caminhos mínimos e diagramas de Voronoi em um grafo com topologia de grade. Para o problema de análise de fluxos de dados, apresentamos uma estrutura de dados paralelizável, baseada em Packed Memory Arrays, para indexar dados dinâmicos geo-localizados ao passo que mantém uma boa localidade de memória. / The quest for performance has been a constant through the history of computing systems. It has been more than a decade now since the sequential processing model had shown its first signs of exhaustion to keep performance improvements. Walls to the sequential computation pushed a paradigm shift and established the parallel processing as the standard in modern computing systems. With the widespread adoption of parallel computers, many algorithms and applications have been ported to fit these new architectures. However, in unconventional applications, with interactivity and real-time requirements, achieving efficient parallelizations is still a major challenge. Real-time performance requirement shows up, for instance, in user-interactive simulations where the system must be able to react to the user’s input within a computation time-step of the simulation loop. The same kind of constraint appears in streaming data monitoring applications. For instance, when an external source of data, such as traffic sensors or social media posts, provides a continuous flow of information to be consumed by an online analysis system. The consumer system has to keep a controlled memory budget and deliver a fast processed information about the stream Common optimizations relying on pre-computed models or static index of data are not possible in these highly dynamic scenarios. The dynamic nature of the data brings up several performance issues originated from the problem decomposition for parallel processing and from the data locality maintenance for efficient cache utilization. In this thesis we address data-dependent problems on two different applications: one on physically based simulations and another on streaming data analysis. To deal with the simulation problem, we present a parallel GPU algorithm for computing multiple shortest paths and Voronoi diagrams on a grid-like graph. Our contribution to the streaming data analysis problem is a parallelizable data structure, based on packed memory arrays, for indexing dynamic geo-located data while keeping good memory locality.

The Czech Republic has a very dense network of waterways and a lot of lakes and small ponds. Floods belong to the most frequent natural disasters in the CR. Small water reservoirs in the flood protection system are of great importance. The retention capacity of those water reservoirs and feasibility to control water outflow are used. The aim of this study is to determine the state of preparedness to manage consequences of a possible failure and an accident on one of such water-works of category II, the pond Hvězda. Vulnerability of the area is assessed in terms of preparedness of state and local government authorities responsible for special flood consequences management. Meeting this objective is possible through compliance with the methodological procedure. The procedure implies studying legislation and normatives applied to the area, flood protection, population protection and crisis management. And it also involves evaluation of responsible institutions and the status of their documents concerning planning, and making comparisons with legislation requirements. Another objective is a proposal of my own solutions to the identified failures management. This is a project of planning documents completion, to be specific, a plan for the area below the water-works protection. The plan is a general conception and allows itself to be used for any water-work. The thesis also includes a brief elaboration of educational material in the form of a presentation, designed for involved authorities that are supposed to compile the plan, or to participate in its compilation. The objective, content and the method of the plan preparation are outlined. It is useful to inform the entities involved in the special flood management such as the Fire Prevention Unit, the Integrated Rescue System components about this issue. This thesis offers a solution to a specific problem, which is protection of inhabitants and areas located below water-works against a special flood impact. It also suggests the future view of an area vulnerability assessment, which consists in a comprehensive hazard mapping and its evaluation according to a unified methodology in the CR territory and assuring its compatibility within the EU.

The work is concerned with mercury appearance in forest and agricultural soils. There is description of process of specimens collection and treatment. The soil specimens were picked up in the selected habitats in South Bohemia. Among studied areas belongs: Lenora near Prachatice, Břehov near České Budějovice, Lužice near Netolice and Velký Chuchelec near Kaplice. There were collected specimens of forest soils, arable land soils, meadows and pastures. Total content of mercury in soils was determined out by the help of atomic absorbtion spectrometric method (CV-AAS) with technique generating cold vapor and gold trap preconcentration. Outcomes were compared with each other in terms of the farming way, locality and vegetation. The data were treated with statistical method ANOVA in programme STATISTICA CZ6. In forest soils there was found the most total content of mercury in the humic horizons in Lenora area on the Chlustov hill - east 0,574 {$\pm$} 0,042 mg.kg-1 dry matter. The least of all of the total content of mercury in forest soils was measured in the second mineral A2 horizon in Břehov area 0,017 {$\pm$} 0,001 mg.kg -1 dry matter. In the agricultural soils there was found the most total quantity of mercury in Lužice area in meadow soil in taking depth into 15 cm 0,088 {$\pm$} 0,007 mg.kg -1 dry matter. On the contrary for at least of total content of mercury was measured out in locality Lužice in arable land in taking depth into 40 cm 0,012 {$\pm$} 0,0001 mg.kg -1 of dry matter. Submission working hypothesis about the influence of land management have the best statistically significantly proved in locality Lužice and Velky Chuchelec. From the results is evident that the way of the use has affect on content of the total content mercury in soil. But there are some other factors which have influence on the mercury content. In the forest soils there was proved statistically relevant effect of sort and age vegetation on the mercury total contant in soils.

We present new approaches to define and analyze geometric graphs. <p><p>The region-counting distances, introduced by Demaine, Iacono and Langerman, associate to any pair of points (p,q) the number of items of a dataset S contained in a region R(p,q) surrounding (p,q). We define region-counting disks and circles, and study the complexity of these objects. Algorithms to compute epsilon-approximations of region-counting distances and approximations of region-counting circles are presented.<p><p>We propose a definition of the locality for properties of geometric graphs. We measure the local density of graphs using the region-counting distances between pairs of vertices, and we use this density to define local properties of classes of graphs.<p>We illustrate the locality by introducing the local diameter of geometric graphs: we define it as the upper bound on the size of the shortest path between any pair of vertices, expressed as a function of the density of the graph around those vertices. We determine the local diameter of several well-studied graphs such as the Theta-graph, the Ordered Theta-graph and the Skip List Spanner. We also show that various operations, such as path and point queries using geometric graphs as data structures, have complexities which can be expressed as local properties.<p><p>A family of proximity graphs, called Empty Region Graphs (ERG) is presented. The vertices of an ERG are points in the plane, and two points are connected if their neighborhood, defined by a region, does not contain any other point. The region defining the neighborhood of two points is a parameter of the graph. This family of graphs includes several known proximity graphs such as Nearest Neighbor Graphs, Beta-Skeletons or Theta-Graphs. We concentrate on ERGs that are invariant under translations, rotations and uniform scaling of the vertices. We give conditions on the region defining an ERG to ensure a number of properties that might be desirable in applications, such as planarity, connectivity, triangle-freeness, cycle-freeness, bipartiteness and bounded degree. These conditions take the form of what we call tight regions: maximal or minimal regions that a region must contain or be contained in to make the graph satisfy a given property. We show that every monotone property has at least one corresponding tight region; we discuss possibilities and limitations of this general model for constructing a graph from a point set.<p><p>We introduce and analyze sigma-local graphs, based on a definition of locality by Erickson, to illustrate efficient construction algorithm on a subclass of ERGs. / Doctorat en sciences, Spécialisation Informatique / info:eu-repo/semantics/nonPublished

The work dedicates the region of Podblanicko as an outdoor acivity of didactic territory. The description of five concrete excursions follows with a universal characterization of the region. The didactic part is worked by the author theoreticaly of the view of the General Educational Programme and extra concrete School Educational Programme. In the work, there is dedicated a special consideration to the concrete special didactics of individual excursions including author's writing of the working folio for the geological excursion. Powered by TCPDF (www.tcpdf.org)

Excursions are an organizational form of teaching that is relatively often neglected in today's schools. Excursions are very important in education of pupils on grammer and secondary schools, because it allows to combine the knowledge of pupils gained during theoretical lessons in school with practical demonstrations of items, processes and relationships among objects in the terrain. Pupils are better acquainted with the required curriculum and more effectively fulfill the predetermined educational target. This diploma thesis introduces an example of such an excursion into the Krčský les area. In the theoretical part of this diploma thesis are summarized basic didactic aspects related to organizational forms of teaching, excursions, teaching methods and Framework Education Programmes. There are also chracteristics of the Krčský les area focused mainly on the natural conditions, specifically on geological, hydrological, botanical and zoological aspects. The last chapter of the theoretical part is devoted to the protection of the nature the into Krčský les area. The practical part of the diploma thesis is focused on the preparation of specific excursion into Krčský les area and the creation of worksheets for the excursion. The excursion was realized and subsequently evaluated in the last chapter of...

Recent advances in technology have increased awareness of the necessity for automated systems in people’s everyday lives. Artificial systems are more frequently being introduced into environments previously thought to be too perilous for humans to operate in. Some robots can be used to extract potentially hazardous materials from sites inaccessible to humans, while others are being developed to aid humans with laborious tasks. A crucial aspect of all artificial systems is the manner in which they interact with their immediate surroundings. Developing such a deceivingly simply aspect has proven to be significantly challenging, as it not only entails the methods through which the system perceives its environment, but also its ability to perform critical tasks. These undertakings often involve the coordination of numerous subsystems, each performing its own complex duty. To complicate matters further, it is nowadays becoming increasingly important for these artificial systems to be able to perform their tasks in real-time. The task of object recognition is typically described as the process of retrieving the object in a database that is most similar to an unknown, or query, object. Pose estimation, on the other hand, involves estimating the position and orientation of an object in three-dimensional space, as seen from an observer’s viewpoint. These two tasks are regarded as vital to many computer vision techniques and and regularly serve as input to more complex perception algorithms. An approach is presented which regards the object recognition and pose estimation procedures as mutually dependent. The core idea is that dissimilar objects might appear similar when observed from certain viewpoints. A feature-based conceptualisation, which makes use of a database, is implemented and used to perform simultaneous object recognition and pose estimation. The design incorporates data compression techniques, originally suggested by the image-processing community, to facilitate fast processing of large databases. System performance is quantified primarily on object recognition, pose estimation and execution time characteristics. These aspects are investigated under ideal conditions by exploiting three-dimensional models of relevant objects. The performance of the system is also analysed for practical scenarios by acquiring input data from a structured light implementation, which resembles that obtained from many commercial range scanners. Practical experiments indicate that the system was capable of performing simultaneous object recognition and pose estimation in approximately 230 ms once a novel object has been sensed. An average object recognition accuracy of approximately 73% was achieved. The pose estimation results were reasonable but prompted further research. The results are comparable to what has been achieved using other suggested approaches such as Viewpoint Feature Histograms and Spin Images. / Dissertation (MEng)--University of Pretoria, 2013. / gm2014 / Electrical, Electronic and Computer Engineering / unrestricted

The study describes tax competition among cantons within Swiss Confederation. In the introductory chapter the reader gets familiarized with regional division of the country. There are three levels -- Federation, cantons and municipalities. Determination of tax competence is very important - for this study especially the limitation of the tax competition space is relevant. There are the most important legislative sources mentioned. In next chapter there is balancing mechanism described which eliminates the tax load diference among swiss cantons. In the last chapter the current situation in Switzerland is confronted with tax competition theory. There is focus on five cantons in central Switzerland - the most outstanding practises of canton Obwalden are closely described.

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