988 resultados para Reference frame transformation


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Syfte och utgångspunkt:    Att utifrån fyra organisationer undersöka faktorer som är viktiga för arbete med expatriering och att använda Mendenhall, Dunbar och Oddous modell som inspiration för att skapa en egen modell med faktorer värdefulla för en expatrieringsprocess.   Forskningsresan:                 Utifrån referensram samt ett empiriskt resultat av intervjuer identifieras fyra kategorier, betydelse av att ta med familjen, mentorskap och stöd, anpassning till kultur och karriärplanering. Det empiriska resultatet samt referensramen är sedan grunden till analys och slutsats.   Slutsats:                              I slutsatsen presenteras betydelsefulla faktorer för utgången av studiens syfte.   Dessa faktorer används sedan i den modell författarna skapat. Modellen visar hur behovet av de fyra kategorierna är beroende av den planerade utlandsstationeringens längd.   Metod:                                Författarna av studien utgår från en kvalitativ ansats med djupintervjuer som metod. Det empiriska resultatet baseras på det material som framkommit genom djupintervjuer med  respondenterna från de fyra organisationerna.

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The Sagnac effect is an important phase coherent effect in optical and atom interferometers where rotations of the interferometer with respect to an inertial reference frame result in a shift in the interference pattern proportional to the rotation rate. Here, we analyze the Sagnac effect in a mesoscopic semiconductor electron interferometer. We include in our analysis the Rashba spin-orbit interactions in the ring. Our results indicate that spin-orbit interactions increase the rotation-induced phase shift. We discuss the potential experimental observability of the Sagnac phase shift in such mesoscopic systems.

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This study aims at disclosing the roots of contemporary consumer culture. By emphasizing the relationship between consumption and cultural and political dimensions of social life, this analysis focuses on some processes that took place in Europe since the end of Middle Ages throughout the XVIII century - e.g. the rise of absolutism, the development of royal courts and of a new life-style among them (they are the social group in which the first modern consumption features came to light), the upcoming of present (and no longer past) as the main reference frame for action, a new balance between tradition and novelty, the emergence of individualism - which are crucial to understand the genesis of present consumer standards and values.

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Este é um trabalho teórico que analisa a questão do estudo dos determinantes da Escolha Ocupacional e do Ingresso na Ocupação. Inicialmente realiza uma crítica de algumas formulações teóricas vigentes, apontando o contefido ideológico a elas subjacente, em especial no caso de formulações de natureza psicológica. A seguir propoe alguns pontos de referência para o estabelecimento de uma posição teórica alternativa, que parte da considera. çao do indivíduo numa perspectiva de totalidade, do indi víduo trabalhador na concretude das relações capitalistas de produção e de trabalho. Nessa abordagem recomenda-se aos que se dedicam ao estudo dos aspectos psíquicos que não deixem que a ê~ . fase no psicológico encubra a importância do econômico. Igualmente os que tratam do econômico nao devem descurar o papel dos aspectos psíquicos.

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A presente dissertação de mestrado versa sobre o significado de República no militar do Exército Brasileiro. Tal significado é buscado nas manifestações publicadas, no interior da corporação, nos dias 15 de novembro dos cem anos deste regime vigente no país. Delimita-se qual o objeto da Psicologia Social, e, para fundamentação da escolha do quadro de referência teórico, apresenta-se uma crítica aos modelos fundados no Positivismo e no Materialismo Histórico, para então se optar pela História das Mentalidades e pela Teoria das Representações Sociais. Utiliza-se as "Ordens do Dia" como material. Importa ressaltar que apresentam-se tais documentos num capitulo e não em anexos, para enfatizar que eles são a base desta dissertação. São considerados, não coadjuvantes, mas figuras centrais neste cenário. Faz-se uma análise destas "Ordens do Dia", privilegiando-se as ideias de ordem, progresso, segurança e desenvolvimento. Posteriormente é feita uma sobreposição das ideologias dentro do Exército que dominaram as conjunturas na estrutura republicana, com a representação social de República no Exército Brasileiro. Tal sobreposição corrobora o papel ativo da Representação Social.

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Conventional control strategies used in shunt active power filters (SAPF) employs real-time instantaneous harmonic detection schemes which is usually implements with digital filters. This increase the number of current sensors on the filter structure which results in high costs. Furthermore, these detection schemes introduce time delays which can deteriorate the harmonic compensation performance. Differently from the conventional control schemes, this paper proposes a non-standard control strategy which indirectly regulates the phase currents of the power mains. The reference currents of system are generated by the dc-link voltage controller and is based on the active power balance of SAPF system. The reference currents are aligned to the phase angle of the power mains voltage vector which is obtained by using a dq phase locked loop (PLL) system. The current control strategy is implemented by an adaptive pole placement control strategy integrated to a variable structure control scheme (VS-APPC). In the VS-APPC, the internal model principle (IMP) of reference currents is used for achieving the zero steady state tracking error of the power system currents. This forces the phase current of the system mains to be sinusoidal with low harmonics content. Moreover, the current controllers are implemented on the stationary reference frame to avoid transformations to the mains voltage vector reference coordinates. This proposed current control strategy enhance the performance of SAPF with fast transient response and robustness to parametric uncertainties. Experimental results are showing for determining the effectiveness of SAPF proposed control system

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In this work, the variable structure adaptive pole placement controller (VS-APPC) robustness and performance are evaluated and this algorithm is applied in a motor control system. The controller robustness evaluation will be done through simulations, where will be introduced in the system the following adversities: time delay, actuator response boundeds, disturbances, parametric variation and unmodeled dynamics. The VS-APPC will be compared with PI control, pole placement control (PPC) and adaptive pole placement controller (APPC). The VS-APPC will be simulated to track a step and a sine reference. It will be applied in a three-phase induction motor control system to track a sine signal in the stator reference frame. Simulation and experimental results will prove the efficiency and robustness of this control strategy

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Conventional control strategies used in shunt active power filters (SAPF) employs real-time instantaneous harmonic detection schemes which is usually implements with digital filters. This increase the number of current sensors on the filter structure which results in high costs. Furthermore, these detection schemes introduce time delays which can deteriorate the harmonic compensation performance. Differently from the conventional control schemes, this paper proposes a non-standard control strategy which indirectly regulates the phase currents of the power mains. The reference currents of system are generated by the dc-link voltage controller and is based on the active power balance of SAPF system. The reference currents are aligned to the phase angle of the power mains voltage vector which is obtained by using a dq phase locked loop (PLL) system. The current control strategy is implemented by an adaptive pole placement control strategy integrated to a variable structure control scheme (VS¡APPC). In the VS¡APPC, the internal model principle (IMP) of reference currents is used for achieving the zero steady state tracking error of the power system currents. This forces the phase current of the system mains to be sinusoidal with low harmonics content. Moreover, the current controllers are implemented on the stationary reference frame to avoid transformations to the mains voltage vector reference coordinates. This proposed current control strategy enhance the performance of SAPF with fast transient response and robustness to parametric uncertainties. Experimental results are showing for determining the effectiveness of SAPF proposed control system

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A precise fomulation of the strong Equivalence Principle is essential to the understanding of the relationship between gravitation and quantum mechanics. The relevant aspects are reviewed in a context including General Relativity but allowing for the presence of torsion. For the sake of brevity, a concise statement is proposed for the Principle: An ideal observer immersed in a gravitational field can choose a reference frame in which gravitation goes unnoticed. This statement is given a clear mathematical meaning through an accurate discussion of its terms. It holds for ideal observers (time-like smooth non-intersecting curves), but not for real, spatially extended observers. Analogous results hold for gauge fields. The difference between gravitation and the other fundamental interactions comes from their distinct roles in the equation of force.

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Here, a simplified dynamical model of a magnetically levitated body is considered. The origin of an inertial Cartesian reference frame is set at the pivot point of the pendulum on the levitated body in its static equilibrium state (ie, the gap between the magnet on the base and the magnet on the body, in this state). The governing equations of motion has been derived and the characteristic feature of the strategy is the exploitation of the nonlinear effect of the inertial force associated, with the motion of a pendulum-type vibration absorber driven, by an appropriate control torque [4]. In the present paper, we analyzed the nonlinear dynamics of problem, discussed the energy transfer between the main system and the pendulum in time, and developed State Dependent Riccati Equation (SDRE) control design to reducing the unstable oscillatory movement of the magnetically levitated body to a stable fixed point. The simulations results showed the effectiveness of the (SDRE) control design. Copyright © 2011 by ASME.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Ciência da Informação - FFC

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A measurement of differential cross sections for the production of a pair of isolated photons in proton-proton collisions at root s = 7 TeV is presented. The data sample corresponds to an integrated luminosity of 5.0 fb(-1) collected with the CMS detector. A data-driven isolation template method is used to extract the prompt diphoton yield. The measured cross section for two isolated photons, with transverse energy above 40 and 25 GeV respectively, in the pseudorapidity range vertical bar eta vertical bar < 2.5, vertical bar eta vertical bar (sic) [1.44, 1.57] and with an angular separation Delta R > 0.45, is 17.2 +/-0.2 (stat) +/-1.9 (syst) +/- 0.4 (lumi) pb. Differential cross sections are measured as a function of the diphoton invariant mass, the diphoton transverse momentum, the azimuthal angle difference between the two photons, and the cosine of the polar angle in the Collins-Soper reference frame of the diphoton system. The results are compared to theoretical predictions at leading, next-to-leading, and next-to-next-to-leading order in quantum chromodynamics.