Current literature on information technology points to a scenario where resistance to change must be considered in all IT implementation processes. However, there is no consistency in the extant literature about the interplay among the... more
Current literature on information technology points to a scenario where resistance to change must be considered in all IT implementation processes. However, there is no consistency in the extant literature about the interplay among the several triggers to resistance to change in IT. This paper aims at surveying the literature and investigating their roles in IT change management. Fuzzy AHP (Analytical Hierarchical Process) is used to provide greater flexibility in understanding the answers. The results point to two main sets of behaviours (intrinsic and extrinsic), which find support from other management fields. This paper contributes to the literature by showing that contrary to what was formerly believed, resistance to change in IT is not as much linked to technical aspects but to personal and team-level causes.
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Research Interests: Engineering, Supply Chain, Sugar cane, Exportation, Sugar, and 3 morePurchasing, Cane, and Material Flow
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Different laser designs may require high-concentration erbium lasers. The laser efficiency can be measured by the small signal gain (SSG) of the laser media. In this paper an investigation of the SSG for a Er:YLF with 40 mol % of erbium... more
Different laser designs may require high-concentration erbium lasers. The laser efficiency can be measured by the small signal gain (SSG) of the laser media. In this paper an investigation of the SSG for a Er:YLF with 40 mol % of erbium concentration were carried out by means of computational simulation considering several pumping rates and different pulse duration . Results showed that the maximum SSG values for 40% Er concentration are reached for lower pulse durations and high pumping rates. In addition, results suggest that the performance of such lasers can be significantly enhanced by the adjustment of pulse duration and the interval between two consecutive pulses.
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The mechanism involved in the Tm3+(3F4)→Tb3+(7F0,1,2) energy transfer as a function of the Tb concentration was investigated in Tm:Tb-doped germanate (GLKZ) glass. The experimental transfer rate was determined from the best fit of the 3F4... more
The mechanism involved in the Tm3+(3F4)→Tb3+(7F0,1,2) energy transfer as a function of the Tb concentration was investigated in Tm:Tb-doped germanate (GLKZ) glass. The experimental transfer rate was determined from the best fit of the 3F4 luminescence decay due to the Tm→Tb energy transfer using the Burshtein model. The result showed that the 1700nm emission from 3F4 can be completely quenched
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In this work we present the spectroscopic properties of KY3F10 (KY3F) single crystals activated with thulium and co-doped with ytterbium and neodymium ions. The most important processes that lead to the thulium up-conversion emissions in... more
In this work we present the spectroscopic properties of KY3F10 (KY3F) single crystals activated with thulium and co-doped with ytterbium and neodymium ions. The most important processes that lead to the thulium up-conversion emissions in the blue and ultraviolet regions were identified. A time-resolved luminescence spectroscopy technique was employed to measure the luminescence decays and to determine the most important mechanisms involved in the up-conversion process that populates 1G4 and 1D2 (Tm3+) excited states. Analysis of the energy-transfer processes dynamics using selective pulsed-laser excitations in Yb:Tm:Nd, Tm:Nd, and Tm:Yb KY3F crystals show that the energy transfer from Nd3+ to Yb3+ ions is the mechanism responsible for the enhancement of the blue up-conversion efficiency in the Yb:Tm:Nd:KY3F when compared with the Yb:Tm system. A study of the energy transfer processes in Yb:Tm:Nd:KY3F crystal showed that the 1G4 excited level is mainly populated by a sequence of two nonradiative energy transfers that starts well after the Nd3+ and Tm3+ excitation at 797 nm according to: Nd3+ (4F3/2) → Yb3+ (2F7/2) followed by Yb3+ (2F5/2) → Tm (3H4) → Tm3+ (1G4). Results of numerical simulation of the rate equations system showed that a population inversion for 483.1 nm laser emission line is attained for a pumping rate threshold of 98 s−1, which is equivalent to an intensity of 3.3 KW cm−2 for a continuous laser pumping at 797 nm for Yb(30 mol%):Tm(0.5 mol%):Nd(1 mol%):KY3F. Nevertheless, best Yb3+ concentration for the laser emission near 483.1 nm was estimated to be within 40 and 50 mol%. On the other hand, a population inversion was not observed for the case of 960 nm (Yb3+) pumping.
Research Interests: Engineering, Materials Science, Laser Spectroscopy, Applied Physics, Numerical Simulation, and 15 moreMathematical Sciences, Applied, Physical sciences, Erbium, Luminescence, Infrared, Ion, Excited states, Infrared spectra, Materials Processing, Energy Transfer, Optical Pumping, Numerical Solution, Continuous Wave, and Rate Constant
Ultraviolet fluorescence of Nd3+ ions induced by triphotonic excitation process was studied in Nd-doped LiYF4, LiLuF4 and BaY2F8 crystals using a technique of time-resolved spectroscopy. The observed ultraviolet luminescence was due to... more
Ultraviolet fluorescence of Nd3+ ions induced by triphotonic excitation process was studied in Nd-doped LiYF4, LiLuF4 and BaY2F8 crystals using a technique of time-resolved spectroscopy. The observed ultraviolet luminescence was due to transitions between the bottom of 4f25d configuration and 4f3 states of Nd3+ ions. Narrow emission lines superposed to the broadband emissions were observed. A detailed analysis of luminescence
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Research Interests: Engineering, Materials Science, Chemistry, Fluorescence Spectroscopy, Applied Physics, and 14 moreDoping, Numerical Simulation, Mathematical Sciences, Physical sciences, Erbium, Zinc, Time Resolved, Optical physics, Fourier transform, Excited states, Infrared spectra, Energy Transfer, Energy Levels, and Excited State Absorption (ESA)
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Este estudo teve por objetivo mapear o emprego do metodo Analytic Hierarchy Process (AHP) como estrategia ou objeto de pesquisa nos programas brasileiros de pos-graduacao stricto sensu indexados no acervo da Biblioteca Digital Brasileira... more
Este estudo teve por objetivo mapear o emprego do metodo Analytic Hierarchy Process (AHP) como estrategia ou objeto de pesquisa nos programas brasileiros de pos-graduacao stricto sensu indexados no acervo da Biblioteca Digital Brasileira de Teses e Dissertacoes ate o ano de 2016, alem de estabelecer comparacoes e apontar as principais tendencias. Os procedimentos tecnicos consistiram em pesquisa bibliografica para a coleta e tecnicas de estatistica descritiva e analise de redes sociais para tratamento e analise dos dados. Foram identificados 383 documentos, o que significa que o metodo AHP foi empregado em, aproximadamente, 0,734% do total de pesquisas. As areas de Engenharias e Ciencias Sociais Aplicadas concentraram mais de 85% dos estudos, que, em sua maioria, estiveram voltados aos problemas de decisao no setor de infraestrutura, que abrange as atividades de planejamento territorial e urbano, construcao civil, energia, telecomunicacoes e transportes. Constatou-se que o metodo AH...
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A implantação da tecnologia da Internet das Coisas (IoT) traz benefícios à vida, como controle remoto de pragas na agricultura, monitoramento da cadeia de suprimentos, melhoria na educação e monitoramento de pacientes. No entanto, apesar... more
A implantação da tecnologia da Internet das Coisas (IoT) traz benefícios à vida, como controle remoto de pragas na agricultura, monitoramento da cadeia de suprimentos, melhoria na educação e monitoramento de pacientes. No entanto, apesar dos benefícios, existem desafios embutidos na implementação desta tecnologia. Um dos maiores desafios da área é a violação de privacidade e segurança de dados. Portanto, é necessário avaliar a probabilidade de falha dos elementos e, consequentemente, a causa desse problema. Assim, é neste contexto que este trabalho se propõe a identificar, modelar e calcular a probabilidade de falha através de uma análise sistemática, utilizando Redes Bayesianas. Os resultados mostraram que através do uso do modelo proposto foi possível avaliar diferentes cenários para o uso de redes de Internet das Coisas, bem como simular o efeito da probabilidade de falha nos elementos críticos do sistema.
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