Estudos sobre proteção contra os surtos chamados de transitórios rápidos, principalmente os que afetam os sistemas elétricos de potência, exigem que o comportamento dos sistemas de aterramento quando submetidos a esses eventos seja meticulosamente estimado. Isto se deve ao fato de o chamado comportamento dinâmico associado aos sistemas de aterramento, muitas vezes, produzir resultados diferentes do chamado comportamento estático. Em face disso é consenso que, para a realização de tais estudos, é necessário obter um modelo acurado seja do sistema de aterramento como um todo ou dos elementos que o compõe para conseguir uma boa representação nas simulações digitais. Durante as últimas duas décadas muitas tentativas vêem sendo feitas nessa direção. Essas tentativas são baseadas ora em modelos computacionais, os quais são resolvidos numericamente, ora sobre expressões analíticas para as distribuições de tensão e corrente sob simplificações ou condições iniciais especiais. Diversas soluções lidam com as equações de propagação, considerando os parâmetros dos componentes do sistema de aterramento dependentes da freqüência. Outro grupo de métodos baseia-se nos princípios do eletromagnetismo. Neste contexto, este trabalho propõe uma modelagem, usando um bipolo elétrico equivalente, para representar um sistema de aterramento em simulações digitais, por meio de programas baseados no SPICE - simulation program with integrated circuits emphasis. Diferente de modelos anteriores, que usaram o bipolo elétrico para simular apenas o comportamento dinâmico de determinadas partes de um sistema de aterramento, nesta modelagem utiliza-se apenas um bipolo elétrico para simular tanto o comportamento dinâmico quanto o estático. Essa modelagem foi desenvolvida ao longo de um estudo teórico-experimental realizado sobre o tema. / Fast transients protection studies, mainly with regard to electric power systems, require accurate estimation of grounding systems behavior under such phenomena. Therefore, the called dynamic behavior of grounding systems leads those studies, most of cases, to different results from the other called static behavior. For this reason, either the whole grounding system or each one of its components need to be accurately modeled to offer a good representation in digital simulations. Researchers have been made many attempts to this direction, during the last two decades. These attempts are based sometimes on computer models, which are solved numerically, sometimes on analytical expressions for voltage and current distributions under simplifications or special initial conditions. Several solutions deal with the propagation equations, considering the parameters frequency dependence of the grounding system elements. Another class of solution methods is based on the electromagnetism principles. Inserted in this context, the present work proposes a model to represent grounding systems as a whole in digital simulations carried out by computer programs based on SPICE - simulation program with integrated circuits emphasis. This task was performed by using only one experiment-based two-port electric circuit model. Unlike previous works, that explored the two-port electric circuit model to simulate only the dynamic behavior of grounding systems, this work shows the possibility to incorporate both dynamic and static behavior to the two-port electric circuit model. This procedure relies on a methodology developed from a theoretic-experimental study.

Interpretação semântica de imagens tem se mostrado uma das fronteiras mais promissoras da área de Visão Computacional, especificamente aplicada a interpretação imagens. Nas abordagens que estão sendo propostas atualmente, conhecimento visual explicitamente modelado é utilizado com algoritmos de raciocínio simbólico combinados a algoritmos de processamento de imagem a fim de se extrair o conteúdo de imagens e associá-lo a modelos semanticamente ricos. Este trabalho apresenta uma abordagem de interpretação semântica de imagens especificamente voltada para interpretação de gráficos de linhas, chamada S-Chart. Ela consiste um conjunto de modelos de conhecimento e algoritmos que podem ser instanciados para interpretação de gráficos em diversos domínios. Os modelos são representados em três níveis semânticos e aplicam o conceito de ancoramento simbólico (symbol grounding) para mapear as primitivas entre os níveis. Os algoritmos de interpretação propostos fazem a interação entre o raciocínio simbólico de alto nível e os algoritmos de processamento de sinal para os dados brutos dos gráficos analisados. Para demonstrar a aplicabilidade do framework S-Chart, foi desenvolvido o sistema InteliStrata, uma aplicação no domínio da Geologia, voltada para interpretação semântica de gráficos de perfis de poço. Utilizando a aplicação, foram interpretados dois perfis de raios gama capturados em poços de exploração, de modo que o sistema identificasse a presença de Sequências Estratigráficas e superfícies de inundação máximas. Os resultados foram comparados com a interpretação de um geólogo especialista sobre os mesmos dados. O sistema aponta as mesmas sequências já identificadas e oferece outras opções de interpretação compatíveis com as do geólogo utilizando os mesmos dados. O framework S-Chart tem seus pontos fortes nos seus modelos representação de conhecimento visual independentes de domínio, que permitem a utilização do mesmo arcabouço em diferentes aplicações e, em especial, no seu modelo de ancoramento simbólico entre primitivas de representação. / Semantic image interpretation is one of the most promising frontiers in the Computer Vision area, specifically when applied to Image Interpretation. To reach semantic interpretation, visual knowledge explicitly represented is applied by symbolic reasoning algorithms combined with image processing algorithms in order to extract the content of the images and associate it with semantically rich models. This work describes the S-Chart approach, a semantic image interpretation approach designed for interpretation of line charts. It is structured as a set of knowledge models and algorithms that can be instantiated to accomplish chart interpretation in other domains. The models are represented in three semantic levels and apply the concept of symbol grounding in order to map the primitives between the levels. The interpretation algorithms carry out the interaction between the symbolic reasoning in the high level, and the signal processing algorithms in the low level data. In order to demonstrate the applicability of the S-Chart framework, we developed the InteliStrata system, an application in Geology for the semantic interpretation of well log profiles. Using the application, we have interpreted the graphs of two gamma-ray profiles captured in exploration wells, to indicate the position of Stratigraphic Sequences and the maximum flooding surfaces. The results were compared with the interpretation of an experienced geologist using the same data input. The system was able to point the same identified sequences and offered alternative interpretation that were compatible with the geologist interpretation over the data. The S-Chart framework demonstrates its effectiveness on interpretation of pictorial information in knowledge intensive domains. The stronger points of the approach are its domain independent models for visual knowledge representation and, specially, the application of a symbol grounding model to provide a correlation between representation primitives.

Octocorals are important components of many reef benthic communities, and efforts to restore populations following damage events and relocating colonies preceding permitted activities is becoming part of regulatory processes. Because many octocorals have regenerative capabilities ideal for removing branch clippings (fragments), they may make excellent donors, sources of transplants, for restoration efforts. This study examined the effect of fragment size, fragmentation timing, and transplantation on the survivorship, growth, and fecundity of Eunicea flexuosa clippings and donor colonies. Eunicea flexuosa clippings 20 cm in height were transplanted to a ship grounding site offshore southeast Florida in April 2010 and November 2010. Data collected during the June through September spawning months in 2010 and 2011 revealed high survivorship among all transplants (85%), however partial mortality from encrustation by bio-fouling organisms ensued. Growth rates among donor colonies was high. The fecundity of fragments transplanted in May was not negatively affected in 2010; however the fecundity of all transplants was lower than that of donor colonies in 2011, with oocytes failing to reach reproductive size. Re-allocation of energy resources towards tissue repair may account for the low growth and loss in fecundity. This study highlights the importance of evaluating fragment size and collection time in promoting growth and propagation of transplanted octocorals following damage and prior to marine construction events.

Sendo as interrupções, os afundamentos de tensão e as sobretensões distúrbios de Qualidade de Energia Elétrica (QEE) com potencial de grande impacto econômico, estudos que procuram alternativas de mitigação de seus efeitos ou prevenção de sua ocorrência têm sido amplamente realizados nas últimas décadas. Uma das metodologias de avaliação de sua ocorrência é realizada pela predição, que geralmente se concentra em simulações de faltas em parcelas de sistemas elétricos de potência. Nos Procedimentos de Distribuição de Energia Elétrica no Sistema Elétrico Nacional (PRODIST), encontra-se a denominação geral de Variações de Tensão de Curta Duração (VTCD) para estes três tipos de distúrbios, os quais podem ser classificados tanto por sua magnitude quanto por sua duração. Nesse contexto, este trabalho avalia pela predição a influência exercida pela conexão e o aterramento do neutro de transformadores trifásicos nas quantidades de VTCD, especialmente de afundamentos de tensão, e no valor do índice Fator de Impacto (FI) do PRODIST, que são observados em um nó com conexão a um consumidor industrial Realizam-se estudos de caso sobre um sistema de potência simulado no software Alternative Transients Program (ATP), o qual possui dois transformadores em sua rede: um transformador da subestação e outro na entrada do nó do consumidor industrial. Consideram-se duas conexões possíveis para o transformador de entrada, e aplica-se uma resistência de aterramento para o neutro de ambos os transformadores em cada caso, alteram-se o seu valor. Verificam-se as tensões no nó do consumidor industrial de duas formas diferentes: tensões fase-terra e tensões fase-fase. Observa-se, assim, que há diferenças para estas quantidades e para o valor do FI devidas à forma de conexão do transformador de entrada, valor da resistência de aterramento de neutro de ambos os transformadores e formas de verificação das tensões. / Since interruptions, voltage sags and overvoltages are Power Quality (PQ) disturbances with great economic impact potential, studies that seek alternatives to mitigate its effects or to prevent its occurrence have been done widely in the last decades. One of the methodologies to assess its occurrence is performed by prediction, which usually focuses on power systems fault simulations. In the Brazilian norm of PQ, there is the general designation short duration voltage variation (VTCD) for these three types of disturbances, which are classified both in terms of magnitude and duration. In this context, this work assess by the prediction the influence of three-phase transformers winding connection and neutral grounding in the quantities of VTCD, especially voltage sags, and in the index value Impact Factor (FI) of the Brazilian regulation standard, which are observed in a node with connection to an industrial consumer. The case studies are performed on a simulated power system in the Alternative Transients Program (ATP), which has two transformers in its network: one substation transformer and another at entrance of the industrial consumer node. Two possible winding connections are considered for the entrance transformer, and a ground resistance is applied to the neutral of both transformers in each case, being changed their value. Voltages in the industrial consumer node are verified by two different ways: phase-to-ground voltages and phase-to-phase voltages. It is observed that there are differences for these quantities and for the value of the FI due to the winding connection of the entrance transformer, the value of the neutral ground resistance of both transformers and the ways of voltage verification.

Diploma thesis is oriented on measuring and evaluation of grounding conditions of HV pylons. In theoretical part is described theory of grounding including related legislation, impact of electric current on human body, methods of measuring earth resistance, soil resitivity and description of available measurers. Practical part is focused on measuring earth resistance of selected pylons and measuring procedures followed by evaluation of measurements according to person's safety from dangerous touch voltage and impact of lightings. For evauluation of measured data is created supporting tool in MS Excel. In the last part of thesis are described recommendations for cutting-down touch voltages.

My master's thesis is focused on grounding of HV switchgear. The aim of this work is to create a computer program intended for dimensioning of earthing networks. The earthing networks are the most convenient alternative in term of effective grounding and distribution of ponential. They are based on latiny a flat conductor network cables and connection of appliance parts to network. Introduction of the thesis is dedicated to explanation of grounding theory and to description of requirements essential for properly designed earthing system (dimensioning of earthing system). Following chapter brings description of computer program algorithm testing propriety of an assigned earthing network for a particular switchgear. The chapter also contains description of an user interface and explanation of all features, included in the program. Last part provides presentation of program utilization to particular numerical assignment.

This study explored the experiences of prominent jazz vocalists regarding the collaboration between the vocalist and pianist during duo performances. The work relationship between a jazz vocalist and accompanist is a unique phenomenon due to the improvisatory and collaborative nature of jazz. Effective co-performer interaction and communication are two essential components within an improvisational music setting. A spirit of spontaneity ir required in order for improvisation and interpretation to take place in real-time and on stage; aspects which cannot be duplicated or replicated during rehearsals. A qualitative research approach was employed by means of a collective case study, exploring the views and experiences of three prominent South African and three international jazz vocalists. Data was gathered through semi-structured interviews. Furthermore, artefacts including audio and audio-visual recordings of each of these performers were studied to ascertain aspects of the vocal-piano collaboration. Thematic data analysis presented four main themes: (1) individuality; (2) interactive relationships; (3) musicianship; and (4) the present moment. The findings revealed that the roles of both partners within the vocal-piano duo collaboration are evenly distributed, yet have distinctive functions. Each new performance between the same vocal-piano duo is an innovative execution, a skilful and artistic equilibrium. It embodies a companionship playing out on stage in view of an audience, yet with the subtle sharing of musical messages. / Mini Dissertation (MMus)--University of Pretoria, 2017. / UP Postgraduate fund / Music / MMus / Unrestricted

Kollisioner, grundstötningar och andra haverier till sjöss har förekommit lika länge som det funnits fartyg. Dessa olyckor är vanligt förekommande och utgör fara för människor, fartyg, miljö, last och ekonomi. Med dagens utvecklade teknologi finns det bra metoder och utrustning för att undkomma grundstötningar och kollisioner, dock är det fortfarande vanligt förekommande händelser. För att kunna minska denna typ av sjöolyckor är det viktigt att undersöka orsaken till varför de inträffar. Syftet med studien är att undersöka och få en djupare förståelse om varför passagerarfartyg går på grund eller kolliderar i svenska havsområden. För att få fram vilka bidragande faktorer som orsakar dessa typer av sjöolyckor granskas och analyseras 29 haverirapporter från Statens haverikommission (SHK) och Transportstyrelsen. Resultat visar att majoriteten av olyckorna sker i farleder runt om i Sverige. Faktorer som bidrar till olyckorna är bland annat brist på rutiner, accepterat möten i för liten marginal, utkik används på fel sätt och brist på framförhållning. Därmed är det betydelsefullt att fartygen ser över sina rutiner och bryggbemanning. / Collisions, groundings and other accidents have been occuring for as long as ships have existed. These accidents are common and pose a danger to people, ships, the environment, cargo and the economy. With today's developed technology there are good methods and equipment to avoid groundings and collisions, although they are still common. To be able to reduce these types of accidents it is important to investigate the reasons behind them. The purpose of this study is to investigate and develop a deeper understanding as to why passenger ships ground or collide within Swedish waters. To obtain the contributing factors behind these types of sea accidents 29 accident reports from The Swedish Accident Investigation Authority (Statens haverikommission - SHK) and the Swedish Transport Agency (Transportstyrelsen) have been reviewed and analyzed. The results show that the majority of accidents happen in fairways around Sweden. Contributing factors to the accidents include a lack of routines, two ships passing with too small of a margin, lookout used incorrectly and a lack of forward planning. It is therefore of importance that ships review their routines and bridge manning.

Modern broiler houses are expensive to build, maintain, and insure. Protecting them from extreme weather events is a major concern to producers, integrators, and insurance companies. Lightning strikes can cause catastrophic fires and electrical damage and can lead to costly bird losses. A greater understanding of the impact of lightning on the commercial broiler industries of MS and AL is needed. The objectives of this research were collection of baseline resistance data for broiler houses and equipment in both states, and mapping lightning strike densities across MS and AL, evaluating annual, monthly, seasonal, and diurnal patterns. 63.5% of surveyed broiler houses were at or below the recommended 25 Ω (ohms). Ufer grounding resulted in lower resistance ratings than grounding rods. Lightning strike density was elevated in counties near the Gulf Coast, highest during the summer months. Producers should inspect their grounding systems annually to mitigate lightning-induced damage.

Humeans say that laws depend on their instances. Another way of saying this is that the instances explain the laws. However, laws are often used in science to help explain these same instances. If this is true it appears as though the instances help explain themselves, which would be a serious problem for the Humeans (Miller, 2015, pp. 1314-1317). In this essay I expand on a solution proposed by Miller (2015, pp. 1328-1331) that the laws are not explained by their instances but rather grounded by a set of global facts. I develop this into a new framework in which it would be expected for the laws to not be grounded by their instances. I call this framework conjunction monism since the core idea is a that conjunctions ground their conjuncts. I finish with a discussion about the compatibility of conjunction monism and Humeanism.