The present work was performed at HVDC ABB as an initial study on how to adopt probabilistic concepts into the VCSHVDC insulation coordination. Due to large voltage levels in HVDC applications the corresponding insulation need to be properly addressed to ensure a safe, economical and reliable operation. Traditionally, only the maximum overvoltage is considered, where no adoption to the shape of the overvoltage distribution is regarded. Use of probabilistic concepts in the insulation coordination procedure can ideally reduce insulation margins with a maintained low risk of flashover. Analysis and understanding of probabilistic concepts of AC systems is needed in order to implement the concepts into VSC-HVDC. With use of advanced VSC-HVDC models, faults are simulated with varied fault insertion time in PSCAD. The resulting overvoltages from the simulation is gathered using different statistical methods in order to obtain the approximated overvoltage distribution. It was found from the simulation results that use of a Gaussian distribution is inappropriate due to shape variety in the overvoltage distributions. Instead, Kernel Density Estimate can serve as a flexible tool to approximate overvoltage distributions with a variety in number of modes and shape. The retrieved approximated overvoltage distributions are compared with the insulation strength in order to calculate the risk of flashover. The comparison shows that the insulation can be tuned in order to match set requirements. The thesis work should be seen as pilot study, where key problems have been pointed out and recommended further studies are proposed.

Gemeinsamer Workshop von Universitaetsrechenzentrum und Professur Rechnernetze und verteilte Systeme (Fakultaet fuer Informatik) der TU Chemnitz. Workshop-Thema: Infrastruktur der ¨Digitalen Universitaet¨ Dieser Vortrag beschäftigt sich mit KOffice der Officesuite des KDE-Desktop und ihren Komponenten.

Gemeinsamer Workshop von Universitaetsrechenzentrum und Professur "Rechnernetze und verteilte Systeme" der Fakultaet fuer Informatik der TU Chemnitz. Workshop-Thema: Mobilitaet Analyse der Verwendbarkeit der aktuellen Version von KOffice unter Linux/KDE2 zur Gestaltung von Geschäftsdokumenten (Texte, Rechentabellen, Vektorgrafiken, Präsentationen).

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-04-25T19:24:06Z No. of bitstreams: 1 igorabrittacosta.pdf: 36138806 bytes, checksum: 83ce158c21ddf862f92969367375d57e (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-04-26T12:25:25Z (GMT) No. of bitstreams: 1 igorabrittacosta.pdf: 36138806 bytes, checksum: 83ce158c21ddf862f92969367375d57e (MD5) / Made available in DSpace on 2017-04-26T12:25:25Z (GMT). No. of bitstreams: 1 igorabrittacosta.pdf: 36138806 bytes, checksum: 83ce158c21ddf862f92969367375d57e (MD5) Previous issue date: 2016-02-22 / A identificação de elétrons é de fundamental importância para os grupos de física do experimento ATLAS, devido à presença destes no processo final de decaimento de partículas de interesse. Nesse ambiente de física de partículas, a probabilidade de ocorrência de elétrons relevantes aos estudos propostos são baixíssimas em relação às partículas que formam o ruído de fundo, exigindo dos grupos de performance do ATLAS algoritmos com índices de eficiência de detecção dos sinais de interesse e rejeição de ruído de fundo cada vez melhores. Nessa dissertação, os métodos aplicados na identificação de elétrons no experimento ATLAS serão revisados e possíveis otimizações serão avaliadas a partir dos dados produzidos pelo ATLAS. Concentrado no contexto offline, o trabalho reproduz o método baseado em verossimilhança e propõe uma melhoria com o uso da técnica multivariada conhecida como MKDE (do inglês, Multivariate Kernel Density Estimation), capaz de mitigar o erro inserido na consideração de dependência entre as variáveis discriminantes inserida pelo método de Likelihood atualmente em uso pelo ATLAS. Inicialmente, este trabalho se propõe a implementar o método de verossimilhança em uso, que se baseia em densidade univariadas usadas na reconstrução da densidade conjunta das variáveis discriminantes, e a estudar o impacto de possíveis parâmetros relacionados à implementação do algoritmo de estimação de densidades univariadas. Este método será então comparado com o método padrão do ATLAS conhecido como e/γ. Em uma segunda etapa, a implementação do MKDE é inserida através de uma comparação direta com o método univariado. / The electron identification is of fundamental importance for the ATLAS physics groups due to the presence of these in the final process of interest particles decay. In particle physics environment, the occurrence probability of relevant electrons to the proposed studies are very low compared to particles considered background, requiring ATLAS performance groups algorithms with identification efficiency index and background rejection each time better. In this dissertation, the methods applied in the electron identification in ATLAS experiment will be reviewed and possible optimizations will be evaluated from the data produced by the ATLAS experiment. Concentrated in the offline context, the work reproduces the method based on Likelihood and proposes an improvement with the use of multivariate technique known as MKDE (Multivariate Kernel Density Estimation), capable of mitigate the error inserted in consideration of dependence between discriminating variables entered by the method Likelihood currently in use by ATLAS. Initially, this work proposes to implement the method Likelihood in use, which is based on univariate density used in the reconstruction of the joint density of the discriminant variables, and to study the possible impact of parameters related to the implementation of univariate densities estimation algorithm. This method is then compared with the ATLAS standard method known as e/γ. In a second step the implementation of the MKDE is inserted through a direct comparison to the univariate method.

Unterlagen zu einem Vortrag im Rahmen des 4. Chemnitzer Linux-Tages. Neben einem Überblick über Struktur und Eigenschaften wird vor allem auf die Konzepte eingegangen. Den Abschluß bildet die Darstellung von Eigenschaften und Prinzipien grafischer Oberflächen. Zielgruppe dieses Vortrags sind Neueinsteiger und Umsteiger.

Unterlagen zu einem Vortrag im Rahmen des 5. Chemnitzer Linux-Tages. Neben einem Überblick über Struktur und Eigenschaften wird vor allem auf die Konzepte eingegangen. Den Abschluß bildet die Darstellung von Eigenschaften und Prinzipien grafischer Oberflächen. Zielgruppe dieses Vortrags sind Neueinsteiger und Umsteiger.

Context Crime rates are increasing more and more, especially residential burglaries. This thesis includes a study of the Kernel Density Estimation algorithm, and how to use this algorithm for mapping crime patterns based on geographical data. By visualizing patterns as spatial hotspots, law-enforcements can get a better understanding of how criminals think and act.  Objectives The thesis focuses on two experiments, including measuring the accuracy and performance of the KDE algorithm, as well as the analysis of the amount of crime data needed to compute accurate and reliable results.  Methods A Prediction Accuracy Index is used to effectively measure the accuracy of the algorithm. The development of a Python test program, which is used for extracting and evaluating the results is also included in the study.   Results The data from three geographical areas in Sweden, including Stockholm, Gothenburg and Malmoe are analyzed and evaluated over a time period of one year.  Conclusions The study conclude that the usage of the KDE algorithm to map residential burglaries performs well overall when having access to enough crimes. The minimum number of crimes for creating a trustworthy hotspot are presented in the result and conclusion chapters. The results further shows that KDE performs well in terms of execution time and scalability. Finally the study concludes that the amount of data that was available for the study was not enough for producing highly reliable hotspots.

This thesis deals with technologies of SELinux security policy writing. Furthermore the thesis analyzes userspace of GNU/Linux operating system with special focus on KDE desktop environment. On the basis of this analysis a bottom-up methodics to create a security policy is devised. Acquired knowledge is then used in practice when realizing the main goal of the thesis, which is to create example security policies for chosen KDE applications. When describing technologies of security policy writing the thesis draws information from available sources of information. Input for userspace analysis are available electronic sources of information and author's own experience with analyzed applications. This is used with common philosophic principles to devise bottom-up methodics of policy writting. Following act of policy building draws from defined security goals, acquired knowledge, created methodics and defined usecases. Theoretical contribution of the thesis is devised methodics of userspace policy building. Main practical contribution are then created example SELinux policies for chosen KDE applications. The structure of the thesis follows its goals. For them three parts are created: background research of available resources, author's own theoretical contemplations and practical output of the thesis. Those parts are then devided into sections according to needs of each topic.

Heaps of fire-cracked stone is an archaeological site category frequently found in Sweden. The heaps were constructed by piling a massive amount of deposited fire-cracked stones and occasionally they contain artefacts, for example, grindstones, ceramics or bones from both humans and animals. The heaps are sometimes also constructed with complex inner stone patterns in forms of e.g. circles and spirals. The heaps have been found all over Sweden, but the largest concentration is associated with the county of Uppland, north of Stockholm in eastern Sweden. In general, the structures have been linked chronologically to the Bronze Age (1800 B.C.–500 B.C.), although the heaps might be one of the least understood features of Scandinavian prehistory, as a result of their complex and varying content and spatial location. The remains are thoroughly debated, and the interpretation of them varies, ranging from graves to household indications, from sacral to profane, from piles of waste to markers of claimed land. The interpretations of the fire cracked stone heaps have mainly been made by comparing the contents of the heaps with finds from the surrounding archaeological landscape.                  In this study, the heaps will be analysed by using a landscape perspective by which they will be examined in relation to dynamic high-resolution shoreline reconstructions, vegetation and local topography. By examining the heaps by applying a high-resolution landscape model, suggests that their placement patterns are strongly connected to past shorelines. The analysis has in turn resulted in a non-prejudicial dating method for the heaps. The shoreline model was in the next step tested by a comparison to 118 published 14C-dates associated with fire-cracked stone heaps by using Kernel Density Estimations (KDE). The main result of the study is that the high-resolution shoreline model, in combination with KDE, provides an effective dating method for heaps of fire-cracked stone, which in the extension suggests an alternative motive for the construction of the heaps.

Depleted water supplies, along with industrial and human waste, are driving a world water crisis that poses a growing risk to food markets, energy production, political stability, and human health (Global Water Security 2012). One obvious example of the this crisis is the more than 1 billion people who obtain their drinking water from contaminated sources (WHO/UNICEF 2006; Clasen et al. 2008). With a projected increase of 1.3 billion people between now and 2050, Africa will add more to the global population than any other world region (Haub and Kaneda 2013). For this research, visual learning design factors were incorporated into water literacy materials in order to study ways in which cultural and societal barriers can be overcome through culture- and gender-appropriate graphics designed to foster visual storytelling in the West African country of Niger. Women were targeted as the study population since they are the primary water fetchers and handlers in sub-Saharan Africa. Eye-tracking technology and GIS tools were used for quantification of the visual design characteristics. Research was conducted in 23 villages along the Niger River, and included 510 interviews, 693 focus group participants, 9 different cultural groups, over 30 hours of audio interviews, and 464 eye-tracking trials. Tobii X2-60 eye-tracking equipment was used in bush maternity wards, medicinal depositories, and mud-brick homes. Eye-tracking data were imported into an ArcGIS platform, where kernel density estimation (KDE) analyses were performed in an effort to compare and contrast the KDE of varying education levels, age groups, ethnic groups, and village types. Spatial autocorrelation analyses were used to evaluate whether the spatial pattern of attribute values (fixation time) was clustered, dispersed, or random. Results from this research suggest that visual communication can be used to overcome low education and cultural barriers for waterborne disease prevention. Using an adaptive visual-learning approach for the research method provided a creative alternative to conventional water-education materials, as most do not consider mother tongue and low literacy. Through visual communication, a novel way has been developed to understand how disadvantaged populations in sub-Saharan Africa visually process water literacy materials.