952 resultados para direct current (dc) model
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A redução dos efetivos permanentes das Forças Armadas reforça a necessidade de mecanismos que garantam o seu crescimento. Desses mecanismos, a Convocação e a Mobilização no Exército Português constituiu-se como o objeto de estudo do presente trabalho. Com o objetivo da investigação de identificar contributos para adequar o modelo de Convocação e Mobilização aos desafios futuros, as análises ao atual modelo nacional, espanhol, britânico e francês, permitem identificar procedimentos de melhoria. A metodologia utilizada, baseada na análise documental complementada por entrevistas e inquéritos, permite determinar comportamentos das dimensões Qualidade e Oportunidade do modelo nacional. A análise aos ambientes interno e externo, assim como aos seus intervenientes, contribuem para a identificação de potencialidades, vulnerabilidades, oportunidades e desafios futuros a enfrentar. A existência de contributos, tendo em vista a melhoria das dimensões Qualidade e Oportunidade do modelo de Convocação e Mobilização do Exército, constituem-se como resultado principal da investigação. Concluiu-se que a Convocação para treino e o recrutamento seletivo, aceites pela maioria dos militares não permanentes inquiridos, depende de bases de dados adequadas. Simultaneamente, a dispersão territorial e o recrutamento regional, a par de uma estratégia de comunicação específica, permitem o incremento do voluntariado e uma adequada resposta a situações de calamidade. Abstract: The reduction of the permanent Armed Forces troops reinforces the need for mechanisms to ensure their growth. With these mechanisms, the Convocation and the Mobilization in the Portuguese Army was established as the present object of study work. With the aim of the investigation to identify contributions to bring the Convocation and Mobilization model to future challenges, the analyses of the current national model, Spanish, British and French, allow us to identify improvement procedures. The methodology, based on document analysis, complemented by interviews and surveys, allows us to determine behaviour of the Quality and Opportunity dimensions of the national model. The analysis of the internal and external environments, as well as their stakeholders, contribute for the identification of strength, weakness, opportunities and challenges to be faced in the future. The existence of contributions, in order to improve the Quality and Opportunity dimensions of the Army Convocation and Mobilization model, constitute themselves as the main outcome of this investigation. We concluded that the Convocation for training and selective recruitment, accepted by the majority of non-permanent personnel questioned, depends on appropriate databases. Simultaneously, the territorial dispersion and regional recruitment, along with a dedicated strategic communication, allow the growth of volunteerism and an appropriate response to calamity situations.
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Nos últimos anos, a Gestão de Informação e do Conhecimento (GIC) tem despertado um interesse cada vez maior por parte da comunidade científica e de prestigiadas organizações empresariais e governamentais. A incorporação organizacional desta disciplina possibilitou a correção de lacunas de informação e de conhecimento, contribuindo eficazmente para a superioridade de informação. Desta maneira, este estudo tem por objetivo determinar as opções que permitirão ao Exército Português maximizar a sua eficácia no âmbito da GIC. Posto isto, analisar-se-á primeiramente o impacto da “era da informação” na atual gestão organizacional. Em seguida, proceder-se-á à avaliação do modelo de GIC que melhor servirá uma organização tipo Exército Português, verificando-se, numa fase final, quais os aspetos que caracterizam o atual modelo em vigor no Exército e qual o seu impacto na sua gestão estratégica. Por último, conclui-se com o presente estudo que se encontra em curso uma transformação ao nível de toda a cultura organizacional do Exército, uma vez que a mesma passa a centralizar o seu processo de decisão em rede. Para isso, torna-se essencial a implementação eficaz da GIC, o que é apenas é praticável com a definição de uma estratégia e de um plano de ação para a sua eficaz materialização. Abstract: The Information and Knowledge Management (IKM) is beginning to awaken a growing interest in the academic world as well as in large organizations globally. The implementation of this type of capability allows bridging the information and knowledge gaps contributing to achieve in organizational terms the information superiority. This study focuses on determining the options that will allow the Portuguese Army in order to maximize its effectiveness within the IKM. To achieve this purpose, it begins by analyzing how the "information age" influences the management of organizations. Next, we evaluate which model of IKM that could best serve an organization like the Portuguese Army and finally we analyze which aspects characterizing the current IKM model in the Army and its impact on its Strategic Management. We conclude that the Army is crossing a transformation of the whole organizational culture passing this to centralize its decision process through the network changing the whole paradigm of sharing and obligation to share. For this, it is essential to the implementation of the IKM capacity and this is only possible with the definition of a strategy and action plan for the implementation of this strategy.
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Dissertação para obtenção do grau de Mestre em Arquitectura com Especialização em Gestão Urbanística, apresentada na Universidade de Lisboa - Faculdade de Arquitectura.
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O Policiamento de Proximidade é o modelo de policiamento atual em Portugal, privilegiando uma postura preventiva e dando relevo à pró-atividade das forças policiais. À Guarda Nacional Republicana, enquanto força policial, cabe-lhe zelar pelos direitos, liberdades e garantias dos cidadãos, constitucionalmente protegidos, através dessa atuação preventiva, procurando intensificar pró-ativamente a sua presença no seio da sociedade. Contudo, por vezes é necessário recorrer a uma intervenção de caráter repressivo, a fim de repor a ordem e visando uma prevenção futura, evitando os comportamentos antissociais. Torna-se assim pertinente estudar de que forma se articulam a atuação preventiva e repressiva da GNR, de modo a perceber se é possível existir um equilíbrio entre elas, ou se, por alguma razão, existem limitações no seu emprego. O Destacamento Territorial de Coimbra constitui o estudo de caso. Esta investigação para além de descrever a articulação entre ambas as formas de atuação, pretende ainda identificar aquilo que as caracteriza bem como as suas potencialidades e vulnerabilidades. De forma a recolher a informação pretendida, foram privilegiadas a análise documental, entrevistas ao Comandante de Destacamento Territorial de Coimbra e aos respetivos Comandantes dos Postos Territoriais, bem como questionários aos militares do destacamento responsáveis por exercerem o patrulhamento. Seguidamente procedeu-se à análise de conteúdo dos dados recolhidos. Das conclusões retiradas, salienta-se que a falta de recursos principalmente humanos, corresponde a um problema do destacamento, que dificulta uma ação de patrulhamento contínuo junto do cidadão e que contribui para o Policiamento de Proximidade. Denota-se também a intensa fiscalização rodoviária que, apesar de ter uma natureza preventiva, é interpretada pela população com uma imagem de repressão.
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The low-frequency electromagnetic compatibility (EMC) is an increasingly important aspect in the design of practical systems to ensure the functional safety and reliability of complex products. The opportunities for using numerical techniques to predict and analyze system’s EMC are therefore of considerable interest in many industries. As the first phase of study, a proper model, including all the details of the component, was required. Therefore, the advances in EMC modeling were studied with classifying analytical and numerical models. The selected model was finite element (FE) modeling, coupled with the distributed network method, to generate the model of the converter’s components and obtain the frequency behavioral model of the converter. The method has the ability to reveal the behavior of parasitic elements and higher resonances, which have critical impacts in studying EMI problems. For the EMC and signature studies of the machine drives, the equivalent source modeling was studied. Considering the details of the multi-machine environment, including actual models, some innovation in equivalent source modeling was performed to decrease the simulation time dramatically. Several models were designed in this study and the voltage current cube model and wire model have the best result. The GA-based PSO method is used as the optimization process. Superposition and suppression of the fields in coupling the components were also studied and verified. The simulation time of the equivalent model is 80-100 times lower than the detailed model. All tests were verified experimentally. As the application of EMC and signature study, the fault diagnosis and condition monitoring of an induction motor drive was developed using radiated fields. In addition to experimental tests, the 3DFE analysis was coupled with circuit-based software to implement the incipient fault cases. The identification was implemented using ANN for seventy various faulty cases. The simulation results were verified experimentally. Finally, the identification of the types of power components were implemented. The results show that it is possible to identify the type of components, as well as the faulty components, by comparing the amplitudes of their stray field harmonics. The identification using the stray fields is nondestructive and can be used for the setups that cannot go offline and be dismantled
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Transcranial direct current stimulation (tDCS) is a method of non-invasive brain stimulation widely used to modulate cognitive functions. Recent studies, however, suggests that effects are unreliable, small and often non-significant at least when stimulation is applied in a single session to healthy individuals. We examined the effects of frontal and temporal lobe anodal tDCS on naming and reading tasks and considered possible interactions with linguistic activation and selection mechanisms as well possible interactions with item difficulty and participant individual variability. Across four separate experiments (N, Exp 1A = 18; 1B = 20; 1C = 18; 2 = 17), we failed to find any difference between real and sham stimulation. Moreover, we found no evidence of significant effects limited to particular conditions (i.e., those requiring suppression of semantic interference), to a subset of participants or to longer RTs. Our findings sound a cautionary note on using tDCS as a means to modulate cognitive performance. Consistent effects of tDCS may be difficult to demonstrate in healthy participants in reading and naming tasks, and be limited to cases of pathological neurophysiology and/or to the use of learning paradigms.
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Healthy young adults demonstrate a group-level, systematic preference for stimuli presented in the left side of space relative to the right (‘pseudoneglect’) (Bowers & Heilman, 1980). This results in an overestimation of features such as size, brightness, numerosity and spatial frequency in the left hemispace, probably as a result of right cerebral hemisphere dominance for visuospatial attention. This spatial attention asymmetry is reduced in the healthy older population, and can be shifted entirely into right hemispace under certain conditions. Although this rightward shift has been consistently documented in behavioural experiments, there is very little neuroimaging evidence to explain this effect at a neuroanatomical level. In this thesis, I used behavioural methodology and electroencephalography (EEG) to map spatial attention asymmetries in young and older adults. I then use transcranial direct current stimulation (tDCS) to modulate these spatial biases, with the aim of assessing age-related differences in response to tDCS. In the first of three experiments presented in this thesis, I report in Chapter Two that five different spatial attention tasks provide consistent intra-task measures of spatial bias in young adults across two testing days. There were, however, no inter-task correlations between the five tasks, indicating that pseudoneglect is at least partially driven by task-dependent patterns of neural activity. In Chapter Three, anodal tDCS was applied separately to the left (P5) and right (P6) posterior parietal cortex (PPC) in young and older adults, with an aim to improve the detection of stimuli appearing in the contralateral visual field. There were no age differences in response to tDCS, but there were significant differences depending on baseline performance. Relative to a sham tDCS protocol, tDCS applied to the right PPC resulted in maintained visual detection across both visual fields in adults who were good at the task at baseline. In contrast, left PPC tDCS resulted in reduced detection sensitivity across both visual fields in poor performers. Finally, in Chapter Four, I report a right-hemisphere lateralisation of EEG activity in young adults that was present for long (but not short) landmark task lines. In contrast, older adults demonstrated no lateralised activity for either line length, thus providing novel evidence of an age-related reduction of hemispheric asymmetry in older adults. The results of this thesis provide evidence of a highly complex set of factors that underlie spatial attention asymmetries in healthy young and older adults.
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In the current context of education, parents, students, teachers, media and other sectors of Costa Rican society, express concern about the problem of school violence, a social phenomenon that has been increasing in recent years. Its manifestations are perceived by means of abuse behavior, intimidation, verbal or physical abuse among youth, which are constructed through cultural practices. Therefore, to understand this problem, reflection about possible causes is in order, taking into account the context in which social interaction is developed in each school. Some of the manifestations of violence are rooted in the family, the community, the imitation of the behavioral patterns, and the influence of mass media. Moreover, these behaviors are reinforced by the current curriculum model, generating resistance to institutional rules.
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A new study on suspension bridges has been prompted by the big disaster of the Tacoma Narrow Bridge at half its design speed. The aerodynamic instability of long-span bridges has been studied using wind tunnel tests. As a result of improved aerodynamic performance from the geometrical configuration of the bridge deck, the aerodynamic criteria for suspension and cable-stayed bridges have become well established in recent years, thereby allowing longer bridge spans to be developed. Although the Messina Strait Bridge has yet to be constructed, we are looking forward to evaluating the impact of different deck cross-sections on both aerodynamic stability and cost reduction. To further improve the aerodynamic characteristics of long-span suspension bridges, an optimized multi-box bridge deck model with two side decks for traffic lanes, two middle railway decks, and three gaps separating them has been proposed aerodynamic performance has been experimentally verified. 1:80 scale wind tunnel tests have been conducted. According to the current MIDAS Model, the first torsional and the first vertical frequency ratios are 1.27787 and 1.36[1] respectively. It is the torsional/vertical frequency ratio, combined with the deck aerodynamic properties, that determines the wind response properties of the bridge for the most dangerous possible form of aeroelastic instability. The classic flutter is caused by the coupling of torsional and vertical modes. Stabilizing cables to the deck could be a solution to this classic flutter by reducing lateral displacement of the deck and increasing frequency ratios. Stabilizing cables will be installed on the deck in three different orientations: vertical, inclined, and horizontal, with diameters of 80 cm, 60 cm, and 40 cm in each orientation respectively. An overview of the research undertaken on this topic will be presented, as well as the most important findings.
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"October 1971."
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Includes index.
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"March 1971."
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"September 1970."
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"November 1971."
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Includes index.