O desempenho de uma linha de transmissão de energia está diretamente ligado ao número médio anual de descargas que nela incidem, o qual depende da densidade média de descargas ao solo na região e também do grau de exposição da linha. Modelos com diferentes graus de complexidade são encontrados na literatura para a estimativa da área de atração de estruturas a descargas atmosféricas. Entretanto, além das grandes simplificações sobre a física das descargas nas quais a maioria desses modelos se baseia, até recentemente não era possível considerar a configuração tridimensional das estruturas. Essa é uma limitação importante, pois detalhes do objeto afetam o campo elétrico e, consequentemente, o processo de formação do líder ascendente. Nesse contexto, o modelo desenvolvido em 2006 por Becerra e Cooray - SLIM (\"self-consistently interception model\") utiliza os conceitos mais recentes da física das descargas para a análise dos processos de formação e propagação do líder. Ao contrário dos demais modelos, o SLIM possibilita que se leve em conta a geometria tridimensional da estrutura. O modelo foi validado com base em comparações entre valores de campo elétrico para estabilização do líder em função da altura calculados e medidos em experimentos utilizando a técnica de descargas provocadas por foguetes, tendo-se obtido excelente concordância entre os resultados. Este trabalho destaca os aspectos mais importantes do SLIM e apresenta uma análise comparativa do mesmo com outros modelos bastante conhecidos, como o Modelo Eletrogeométrico, o Modelo de Eriksson e o Modelo de Rizk, além do procedimento simplificado recomendado pelo Guia IEEE Std. 1243. A análise é feita em termos da distância e do raio de atração, do número de descargas incidentes em uma linha de transmissão e do desempenho da mesma frente a descargas atmosféricas, discriminando as taxas de falhas causadas por falha de blindagem e por \"backflashover\". / In general, about 20 % to 60 % of the electric power service interruptions of distribution lines are attributed to lightning. For transmission lines, a typical figure is 70 %. The appraisal of the lightning performance of a power line is related to its mean flash collection rate, which depends on the mean ground flash density of the region and on the line exposure to direct lightning strokes. Models of different degrees of complexity are found in the literature for the estimation of lightning striking distances of objects and structures. However, besides the oversimplifications of the physical nature of the lightning discharge on which most of the models are based, till recently the tridimensional structure configuration could not be considered. This is an important limitation, as edges and other details of the object affect the electric field and, consequently, the upward leader initiation. Within this context, the self-consistently interception model (SLIM) proposed in 2006 by Becerra and Cooray is state-of-the-art leader inception and propagation leader model based on the physics of leader discharges which, unlike the other existing models, enables the tridimensional geometry of the structure to be taken into account. For the validation of the model, data obtained in rocket-triggered lightning experiments were used and an excellent agreement was found between measured and calculated leader stabilization electric fields as a function of the height of the rocket. This work describes the most important aspects of the new model and presents a comparative analysis of SLIM and other well-known model such as the Electrogeometric Model (EGM), Erikssons Model, and Rizks Model, as well as the simplified procedure recommended by IEEE Std. 1243. The analysis is done in terms of the striking distance, attractive radius, and the flash collection rate of a transmission line, as well as on its lightning performance, discriminating between the failure rates caused by shielding failure and backflashover.

O desempenho de uma linha de transmissão de energia está diretamente ligado ao número médio anual de descargas que nela incidem, o qual depende da densidade média de descargas ao solo na região e também do grau de exposição da linha. Modelos com diferentes graus de complexidade são encontrados na literatura para a estimativa da área de atração de estruturas a descargas atmosféricas. Entretanto, além das grandes simplificações sobre a física das descargas nas quais a maioria desses modelos se baseia, até recentemente não era possível considerar a configuração tridimensional das estruturas. Essa é uma limitação importante, pois detalhes do objeto afetam o campo elétrico e, consequentemente, o processo de formação do líder ascendente. Nesse contexto, o modelo desenvolvido em 2006 por Becerra e Cooray - SLIM (\"self-consistently interception model\") utiliza os conceitos mais recentes da física das descargas para a análise dos processos de formação e propagação do líder. Ao contrário dos demais modelos, o SLIM possibilita que se leve em conta a geometria tridimensional da estrutura. O modelo foi validado com base em comparações entre valores de campo elétrico para estabilização do líder em função da altura calculados e medidos em experimentos utilizando a técnica de descargas provocadas por foguetes, tendo-se obtido excelente concordância entre os resultados. Este trabalho destaca os aspectos mais importantes do SLIM e apresenta uma análise comparativa do mesmo com outros modelos bastante conhecidos, como o Modelo Eletrogeométrico, o Modelo de Eriksson e o Modelo de Rizk, além do procedimento simplificado recomendado pelo Guia IEEE Std. 1243. A análise é feita em termos da distância e do raio de atração, do número de descargas incidentes em uma linha de transmissão e do desempenho da mesma frente a descargas atmosféricas, discriminando as taxas de falhas causadas por falha de blindagem e por \"backflashover\". / In general, about 20 % to 60 % of the electric power service interruptions of distribution lines are attributed to lightning. For transmission lines, a typical figure is 70 %. The appraisal of the lightning performance of a power line is related to its mean flash collection rate, which depends on the mean ground flash density of the region and on the line exposure to direct lightning strokes. Models of different degrees of complexity are found in the literature for the estimation of lightning striking distances of objects and structures. However, besides the oversimplifications of the physical nature of the lightning discharge on which most of the models are based, till recently the tridimensional structure configuration could not be considered. This is an important limitation, as edges and other details of the object affect the electric field and, consequently, the upward leader initiation. Within this context, the self-consistently interception model (SLIM) proposed in 2006 by Becerra and Cooray is state-of-the-art leader inception and propagation leader model based on the physics of leader discharges which, unlike the other existing models, enables the tridimensional geometry of the structure to be taken into account. For the validation of the model, data obtained in rocket-triggered lightning experiments were used and an excellent agreement was found between measured and calculated leader stabilization electric fields as a function of the height of the rocket. This work describes the most important aspects of the new model and presents a comparative analysis of SLIM and other well-known model such as the Electrogeometric Model (EGM), Erikssons Model, and Rizks Model, as well as the simplified procedure recommended by IEEE Std. 1243. The analysis is done in terms of the striking distance, attractive radius, and the flash collection rate of a transmission line, as well as on its lightning performance, discriminating between the failure rates caused by shielding failure and backflashover.

Research suggests that interruptions are ubiquitous in healthcare settings and have a negative impact on patient safety. However, there is a lack of solutions to reduce harm arising from interruptions. Therefore, this research aimed to design and test the effectiveness of interventions to mitigate the effects of interruptions during medication administration. A three-phased study was conducted. First, direct observation was conducted to quantify the state of interruptions in an ambulatory unit where nurses routinely administered high-risk medications. Secondly, a user-centred approach was used to design interventions targeting errors arising from these interruptions. Finally, the effectiveness of these interventions was evaluated through a high-fidelity simulation experiment. Results showed that medication administration error rates decreased significantly on 4 of 7 measures with the use of interventions, compared to the control condition. Results of this work will help guide the implementation of interventions in nursing environments to reduce medication errors caused by interruptions.

Research suggests that interruptions are ubiquitous in healthcare settings and have a negative impact on patient safety. However, there is a lack of solutions to reduce harm arising from interruptions. Therefore, this research aimed to design and test the effectiveness of interventions to mitigate the effects of interruptions during medication administration. A three-phased study was conducted. First, direct observation was conducted to quantify the state of interruptions in an ambulatory unit where nurses routinely administered high-risk medications. Secondly, a user-centred approach was used to design interventions targeting errors arising from these interruptions. Finally, the effectiveness of these interventions was evaluated through a high-fidelity simulation experiment. Results showed that medication administration error rates decreased significantly on 4 of 7 measures with the use of interventions, compared to the control condition. Results of this work will help guide the implementation of interventions in nursing environments to reduce medication errors caused by interruptions.

This dissertation examines the effects of career interruptions on workers’ wages. In chapter four I examine whether controlling for the type of interruption differently affects men’s and women’s wages and therefore can be used to explain the remaining gender wage differences. The increased participation of married women in the labor force has increased their wages from just 30% of men’s wages in 1890 to nearly 80% as of 2001. Thus, although the gender wage gap has narrowed over time, it has yet to be eliminated. One argument for the persistence of the gender wage gap is that previously researchers have used poor measures of experience to estimate men’s and women’s wages. Although previous studies have made strides in measuring experience, including controls for the timing of work experience, the gender wage gap persists. I extend the wage-gap literature by including controls for the types of interruptions men and women encounter. Because they typically experience different types of interruptions, I examine whether the varying types affect wages differently. I control for the types of interruptions and find similar effects for men’s and women’s wages. My study shows that types of job interruptions do not explain the remaining wage differentials. The fifth chapter extends from the fourth chapter by including controls for all periods of unpaid leave from work. I examine whether wage differences exist between workers who return to their current employer post-interruption versus those who change employers post-interruption. I find differences in the wage effects from different types of unpaid leave for men and women. Chapter six extends from previous chapters by including controls for all periods of paid leave from work in addition to unpaid leaves from work. I examine whether depreciation effects occur when women spend time out of work but receive compensation through paid maternity leaves. I find no evidence that time out of work because of paid maternity leaves depreciates skills.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / As interrupÃÃes no fornecimento de energia elÃtrica provocam diversos prejuÃzos econÃmicos Ãs concessionÃrias e aos seus clientes cuja extensÃo està associada, principalmente, à freqÃÃncia e duraÃÃo do evento e ao tipo de consumidor. Para as concessionÃrias de distribuiÃÃo de energia elÃtrica, que sÃo fiscalizadas pelos ÃrgÃos reguladores e pela sociedade, o grande desafio à a diminuiÃÃo do tempo das interrupÃÃes e, conseqÃentemente, das perdas econÃmicas por elas ocasionadas. Este trabalho apresenta a concepÃÃo e aplicaÃÃo de uma metodologia de anÃlise de desempenho econÃmico dos serviÃos de atendimento emergencial ao consumidor de energia elÃtrica, considerando os impactos econÃmico-financeiros para a distribuidora e para os consumidores de se utilizar um sistema de gestÃo operacional que otimize os parÃmetros que medem este desempenho. No estudo de caso, efetuado sobre o sistema de atendimento emergencial (SAE) da Companhia de Eletricidade do Cearà â COELCE, tem-se como parÃmetro principal de desempenho a duraÃÃo equivalente da interrupÃÃo (DEC), definida pela AgÃncia Nacional de Energia ElÃtrica - ANEEL. Partindo-se do uso de um sistema computacional de gestÃo otimizadora, desenvolvido na Universidade Federal do Cearà (Sistema SAEDE), o qual otimiza o despacho e a alocaÃÃo das equipes de campo responsÃveis pelos serviÃos de reparo na rede elÃtrica, aplicou-se a metodologia proposta no intuito de verificar se haveria benefÃcios justificÃveis para investimentos em sistemas de gestÃo operacional do SAE tanto para a distribuidora quanto para os consumidores. Os principais resultados obtidos atravÃs da aplicaÃÃo da metodologia ao SAE da COELCE apontou que a utilizaÃÃo do Sistema SAEDE contribui para reduzir custos aos usuÃrios devidos Ãs falhas na entrega de energia pela Companhia e, tambÃm, diminui custos a ela imputados quando ocorrem distÃrbios na rede elÃtrica. / Interruptions in electrical supply system normally cause several economic damages both to supplier companies and to their customers which are hard to be estimated. The extension of these damages is a function of the frequency and duration of the blackout and it varies according to the consumerâs characteristics. In Brazil, electrical supplier companies are regulated by federal and state agencies on behalf of the consumers and their major challenge is to reduce breakdown time and consequent economic losses. This work presents the conception and application of a methodology to make the economic performance assessment of customerâs emergency attendance services, according to the parameters and standards set by the Federal Regulatory Agency (ANEEL) and focusing both the supplier and consumers costs related to system breakdown. The proposed methodology was applied to the case of a electrical distribution company in Ceara State, in the northeastern Brazil, to which an optimized operational management system (SAEDE System) was built. SAEDE System is a computational tool that was developed to optimize the dispatch and the staffing of the emergency attendance teams who are employed to repair electrical fails in the regional system. The proposed methodology was applied to search the benefits of investments derived from using SAEDE System in customerâs emergency attendance services of electrical supply Company in Ceara State. Main results of the study point out that the application of SAEDE System contributes to reduce both customerâs costs as well as company costs related to electrical system breakdown in the study area.

As workplaces have become more digitalized and improvements constantly being made in order to optimize performance, it becomes pivotal for managers to understand how stress within organizations can be linked to the information- and communication technology within them. This thesis addresses the research gap of several studies existing regarding technology-related stress, but where a majority of them are quantitative in nature and overlooking the important aspect of organizational culture. The purpose of this thesis is to create an understanding regarding how managers perceive technostress in their organization, and how counterstrategies, if any, are applied. The added value of this research is that it highlights how poorly understood the problem of information overload is amongst certain managers, while highlighting the cultural aspects within organizations and their contributions to the problem. The results show that while many aspects related to information overload are noticed by managers and employees alike, very few – if any – counterstrategies exists in order to highlight and combat the problems that information overload entails. While individual practices existed, few could be realized at an organizational level without first addressing company culture.

Les voitures électriques ont peu d’énergie embarquée pour se mouvoir comparativement aux véhicules thermiques. Il est donc important d’optimiser l’efficacité de la chaîne de traction pour maximiser la distance parcourue entre les recharges. Ces voitures utilisent un ratio simple pour coupler le moteur aux roues de la voiture. Le remplacement du ratio simple par une transmission à plusieurs vitesses dans une voiture électrique améliore l’efficacité du système de propulsion. Cependant, l’introduction d’une transmission à plusieurs ratios ne doit pas seulement améliorer l’efficacité énergétique pour recevoir l’acceptabilité du marché. Elle doit aussi offrir un confort de conduite similaire au ratio simple. L’ajout d’un embrayage de déviation du couple à la transmission manuelle permet de réduire ou d’éliminer les interruptions de celui-ci lors du passage des ratios. Cependant, les technologies d’embrayages à friction secs et humides ne sont pas bien adaptées à cette tâche de déviation du couple cependant. D’abord, l’embrayage est ouvert la majeure partie du temps ce qui fait en sorte qu’un embrayage humide aurait de grandes pertes visqueuses. Ensuite, les moteurs électriques tournent rapidement (11 000 révolutions par minute). Cela fait en sorte que l’embrayage dissipe de grandes quantités de chaleur pour ralentir le moteur avant l’engagement du prochain ratio. Un embrayage sec ne contient pas d’huile pour aider à l’extraction de la chaleur et ses bandes de friction s’usent rapidement sous ces conditions. Ce travail de maîtrise propose d’utiliser un embrayage électromagnétique plutôt qu’un embrayage à friction pour dévier le couple moteur. La démarche de conception d’un tel embrayage est présentée. Premièrement, un modèle analytique simple sert à déterminer les dimensions physiques de l’embrayage pour qu’il développe un certain couple électromagnétique. Ce requis provient des spécifications techniques d’une plateforme véhiculaire électrique disponible à l’Université de Sherbrooke (Projet Phoebus). Deuxièmement, des études par éléments finis des champs magnétiques de l’embrayage servent à valider que l’embrayage produit le niveau de couple désiré. L’embrayage est finalement testé dans une transmission manuelle automatisée installée sur un banc de test dynamométrique. Des changements de ratios sans interruption de couple démontrent la viabilité de l’embrayage à courants de Foucault en tant qu’embrayage de déviation du couple.

The cost of resolving user requests for IT assistance rises annually. Researchers have demonstrated that data warehouse analytic techniques can improve service, but they have not established the benefit of using global organizational data to reduce reported IT incidents. The purpose of this quantitative, quasi-experimental study was to examine the extent to which IT staff use of organizational knowledge generated from data warehouse analytical measures reduces the number of IT incidents over a 30-day period, as reported by global users of IT within an international pharmaceutical company headquartered in Germany. Organizational learning theory was used to approach the theorized relationship between organizational knowledge and user calls received. Archival data from an internal help desk ticketing system was the source of data, with access provided by the organization under study. The population for this study was all calls logged and linked to application systems registered in a configuration database, and the sample was the top 14 application systems with the highest call volume that were under the control of infrastructure management. Based on an analysis of the data using a split-plot ANOVA (SPANOVA) of Time 1, Time 2, treatment, and nontreatment data, there was a small reduction in calls in the number of reported IT incidents in the treatment group, though the reduction was not statistically significant. Implications for positive social change include reassigning employees to other tasks, rather than continuing efforts in this area, enabling employees to support alternative initiatives to drive the development of innovative therapies benefiting patients and improving employee satisfaction.

The introduction of calculation methods for motion induced interruptions (MII) in 1984 introduced a new way to quantify human factors in addition to the motion sickness index (MSI). The 1990 Graham method for calculating MII uses a combination of a vessel's acceleration and roll to determine a "tipping" factor to calculate MII per minute. The Applebee-Baitis (AB) method considered that the motions are implicitly considered in accelerations, and therefore did not require roll to calculate MII. This thesis examines and analyzes the differences between the AB and Graham methods and compares their results for a unique hull form shape, a cylindrical capsule, in rough seas to determine which method is preferred. Two tests were performed by the Naval Surface Warfare Center, Carderock Division (NSWCCD) for the National Aeronautics and Space Administration (NASA) on the Orion Crew Exploration Vehicle (CEV) in post-splashdown conditions. A one-quarter scale model of the CEV was tested at the Aberdeen Test Center in Aberdeen, Maryland. Direct comparison of the analyzed data, MII sensitivity to location, and scaling analyses are examined and future work to further the application of MII calculation methods are proposed. The symmetry of the capsule leads to the assumption that roll and pitch-dominant MII calculations should be on the same order of magnitude. They are not because both MII methods only take roll-motions into account. The inclusion of both pitch and roll motions for the MII calculations is proposed as future work. The Graham method was found to be the more appropriate calculation because it is more conservative, and therefore preferred in the context of crew safety. / Master of Science