800 resultados para performance index


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A eficiência e a racionalidade energética da iluminação pública têm relevante importância no sistema elétrico, porque contribui para diminuir a necessidade de investimentos na construção de novas fontes geradoras de energia elétrica e nos desperdícios energéticos. Apresenta-se como objetivo deste trabalho de pesquisa o desenvolvimento e aplicação do IDE (índice de desempenho energético), fundamentado no sistema de inferência nebulosa e indicadores de eficiência e racionalidade de uso da energia elétrica. A opção em utilizar a inferência nebulosa deve-se aos fatos de sua capacidade de reproduzir parte do raciocínio humano, e estabelecer relação entre a diversidade de indicadores envolvidos. Para a consecução do sistema de inferência nebulosa, foram definidas como variáveis de entrada: os indicadores de eficiência e racionalidade; o método de inferência foi baseado em regras produzidas por especialista em iluminação pública, e como saída um número real que caracteriza o IDE. Os indicadores de eficiência e racionalidade são divididos em duas classes: globais e específicos. Os indicadores globais são: FP (fator de potência), FC (fator de carga) e FD (fator de demanda). Os indicadores específicos são: FU (fator de utilização), ICA (consumo de energia por área iluminada), IE (intensidade energética) e IL (intensidade de iluminação natural). Para a aplicação deste trabalho, foi selecionada e caracterizada a iluminação pública da Cidade Universitária \"Armando de Salles Oliveira\" da Universidade de São Paulo. Sendo assim, o gestor do sistema de iluminação, a partir do índice desenvolvido neste trabalho, dispõe de condições para avaliar o uso da energia elétrica e, desta forma, elaborar e simular estratégias com o objetivo de economizá-la.

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We evaluated the hydrodynamic performance of kangaroo aortic valve matrices (KMs) (19, 21, and 23 mm), as potential scaffolds in tissue valve engineering using a pulsatile left heart model at low and high cardiac outputs (COs) and heart rates (HRs) of 60 and 90 beats/min. Data were measured in two samples of each type, pooled in two CO levels (2.1 +/- 0.7 and 4.2 +/- 0.6 L/min; mean +/- standard errors on the mean), and analyzed using analysis of variance with CO level, HR, and valve type as fixed factors and compared to similar porcine matrices (PMs). Transvalvular pressure gradient (Delta P) was a function of HR (P < 0.001) and CO (P < 0.001) but not of valve type (P = 0.39). Delta P was consistently lower in KMs but not significantly different from PMs. The effective orifice area and performance index of kangaroo matrices was statistically larger for all sizes at both COs and HRs.

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This thesis is concerned with the measurement of the characteristics of nonlinear systems by crosscorrelation, using pseudorandom input signals based on m sequences. The systems are characterised by Volterra series, and analytical expressions relating the rth order Volterra kernel to r-dimensional crosscorrelation measurements are derived. It is shown that the two-dimensional crosscorrelation measurements are related to the corresponding second order kernel values by a set of equations which may be structured into a number of independent subsets. The m sequence properties determine how the maximum order of the subsets for off-diagonal values is related to the upper bound of the arguments for nonzero kernel values. The upper bound of the arguments is used as a performance index, and the performance of antisymmetric pseudorandom binary, ternary and quinary signals is investigated. The performance indices obtained above are small in relation to the periods of the corresponding signals. To achieve higher performance with ternary signals, a method is proposed for combining the estimates of the second order kernel values so that the effects of some of the undesirable nonzero values in the fourth order autocorrelation function of the input signal are removed. The identification of the dynamics of two-input, single-output systems with multiplicative nonlinearity is investigated. It is shown that the characteristics of such a system may be determined by crosscorrelation experiments using phase-shifted versions of a common signal as inputs. The effects of nonlinearities on the estimates of system weighting functions obtained by crosscorrelation are also investigated. Results obtained by correlation testing of an industrial process are presented, and the differences between theoretical and experimental results discussed for this case;

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Accommodating Intraocular Lenses (IOLs), multifocal IOLs (MIOLs) and toric IOLs are designed to provide a greater level of spectacle independency post cataract surgery. All of these IOLs are reliant on the accurate calculation of intraocular lens power determined through reliable ocular biometry. A standardised defocus area metric and reading performance index metric were devised for the evaluation of the range of focus and the reading ability of subjects implanted with presbyopic correcting IOLs. The range of clear vision after implantation of an MIOL is extended by a second focal point; however, this results in the prevalence of dysphotopsia. A bespoke halometer was designed and validated to assess this photopic phenomenon. There is a lack of standardisation in the methods used for determining IOL orientation and thus rotation. A repeatable, objective method was developed to allow the accurate assessment of IOL rotation, which was used to determine the rotational and positional stability of a closed loop haptic IOL. A new commercially available biometry device was validated for use with subjects prior to cataract surgery. The optical low coherence reflectometry instrument proved to be a valid method for assessing ocular biometry and covered a wider range of ocular parameters in comparison with previous instruments. The advantages of MIOLs were shown to include an extended range of clear vision translating into greater reading ability. However, an increased prevalence of dysphotopsia was shown with a bespoke halometer, which was dependent on the MIOL optic design. Implantation of a single optic accommodating IOL did not improve reading ability but achieved high subjective ratings of near vision. The closed-loop haptic IOL displayed excellent rotational stability in the late period but relatively poor rotational stability in the early period post implantation. The orientation error was compounded by the high frequency of positional misalignment leading to an extensive overall misalignment of the IOL. This thesis demonstrates the functionality of new IOL lens designs and the importance of standardised testing methods, thus providing a greater understanding of the consequences of implanting these IOLs. Consequently, the findings of the thesis will influence future designs of IOLs and testing methods.

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Objective - The purpose of this study was to assess cardiac function and cell damage in intrauterine growth-restricted (IUGR) fetuses across clinical Doppler stages of deterioration. Study Design - One hundred twenty appropriate-for-gestational-age and 81 IUGR fetuses were classified in stages 1/2/3 according umbilical artery present/absent/reversed end-diastolic blood flow, respectively. Cardiac function was assessed by modified-myocardial performance index, early-to-late diastolic filling ratios, cardiac output, and cord blood B-type natriuretic peptide; myocardial cell damage was assessed by heart fatty acid–binding protein, troponin-I, and high-sensitivity C-reactive protein. Results - Modified-myocardial performance index, blood B-type natriuretic peptide, and early-to-late diastolic filling ratios were increased in a stage-dependent manner in IUGR fetuses, compared with appropriate-for-gestational-age fetuses. Heart fatty acid–binding protein levels were higher in IUGR fetuses at stage 3, compared with control fetuses. Cardiac output, troponin-I, and high-sensitivity C-reactive protein did not increase in IUGR fetuses at any stage. Conclusion - IUGR fetuses showed signs of cardiac dysfunction from early stages. Cardiac dysfunction deteriorates further with the progression of fetal compromise, together with the appearance of biochemical signs of cell damage.

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The introduction of phase change material fluid and nanofluid in micro-channel heat sink design can significantly increase the cooling capacity of the heat sink because of the unique features of these two kinds of fluids. To better assist the design of a high performance micro-channel heat sink using phase change fluid and nanofluid, the heat transfer enhancement mechanism behind the flow with such fluids must be completely understood. ^ A detailed parametric study is conducted to further investigate the heat transfer enhancement of the phase change material particle suspension flow, by using the two-phase non-thermal-equilibrium model developed by Hao and Tao (2004). The parametric study is conducted under normal conditions with Reynolds numbers of Re = 90–600 and phase change material particle concentrations of ϵp ≤ 0.25, as well as extreme conditions of very low Reynolds numbers (Re < 50) and high phase change material particle concentration (ϵp = 50%–70%) slurry flow. By using the two newly-defined parameters, named effectiveness factor ϵeff and performance index PI, respectively, it is found that there exists an optimal relation between the channel design parameters L and D, particle volume fraction ϵp, Reynolds number Re, and the wall heat flux qw. The influence of the particle volume fraction ϵp, particle size dp, and the particle viscosity μ p, to the phase change material suspension flow, are investigated and discussed. The model was validated by available experimental data. The conclusions will assist designers in making their decisions that relate to the design or selection of a micro-pump suitable for micro or mini scale heat transfer devices. ^ To understand the heat transfer enhancement mechanism of the nanofluid flow from the particle level, the lattice Boltzmann method is used because of its mesoscopic feature and its many numerical advantages. By using a two-component lattice Boltzmann model, the heat transfer enhancement of the nanofluid is analyzed, through incorporating the different forces acting on the nanoparticles to the two-component lattice Boltzmann model. It is found that the nanofluid has better heat transfer enhancement at low Reynolds numbers, and the Brownian motion effect of the nanoparticles will be weakened by the increase of flow speed. ^

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The objective in this work is to build a rapid and automated numerical design method that makes optimal design of robots possible. In this work, two classes of optimal robot design problems were specifically addressed: (1) When the objective is to optimize a pre-designed robot, and (2) when the goal is to design an optimal robot from scratch. In the first case, to reach the optimum design some of the critical dimensions or specific measures to optimize (design parameters) are varied within an established range. Then the stress is calculated as a function of the design parameter(s), the design parameter(s) that optimizes a pre-determined performance index provides the optimum design. In the second case, this work focuses on the development of an automated procedure for the optimal design of robotic systems. For this purpose, Pro/Engineer© and MatLab© software packages are integrated to draw the robot parts, optimize them, and then re-draw the optimal system parts.

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The introduction of phase change material fluid and nanofluid in micro-channel heat sink design can significantly increase the cooling capacity of the heat sink because of the unique features of these two kinds of fluids. To better assist the design of a high performance micro-channel heat sink using phase change fluid and nanofluid, the heat transfer enhancement mechanism behind the flow with such fluids must be completely understood. A detailed parametric study is conducted to further investigate the heat transfer enhancement of the phase change material particle suspension flow, by using the two-phase non-thermal-equilibrium model developed by Hao and Tao (2004). The parametric study is conducted under normal conditions with Reynolds numbers of Re=600-900 and phase change material particle concentrations ¡Ü0.25 , as well as extreme conditions of very low Reynolds numbers (Re < 50) and high phase change material particle concentration (0.5-0.7) slurry flow. By using the two newly-defined parameters, named effectiveness factor and performance index, respectively, it is found that there exists an optimal relation between the channel design parameters, particle volume fraction, Reynolds number, and the wall heat flux. The influence of the particle volume fraction, particle size, and the particle viscosity, to the phase change material suspension flow, are investigated and discussed. The model was validated by available experimental data. The conclusions will assist designers in making their decisions that relate to the design or selection of a micro-pump suitable for micro or mini scale heat transfer devices. To understand the heat transfer enhancement mechanism of the nanofluid flow from the particle level, the lattice Boltzmann method is used because of its mesoscopic feature and its many numerical advantages. By using a two-component lattice Boltzmann model, the heat transfer enhancement of the nanofluid is analyzed, through incorporating the different forces acting on the nanoparticles to the two-component lattice Boltzmann model. It is found that the nanofluid has better heat transfer enhancement at low Reynolds numbers, and the Brownian motion effect of the nanoparticles will be weakened by the increase of flow speed.

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Questa tesi si propone di illustrare il lavoro da me svolto presso l’azienda Ocem Airfield Technology all’interno del magazzino componentistica mirato alla riorganizzazione del supermarket delle linee di assemblaggio nell’ottica della minimizzazione dei tempi di prelievo. La continua ricerca di flessibilità sulla base delle esigenza della clientela ha un drastico effetto sul magazzino e sulla sua gestione. Il magazzino rappresenta un elemento estremamente oneroso nel bilancio aziendale e contribuisce per il 20% ai costi interni dell’impresa. Hanno un ruolo cruciale nel funzionamento aziendale: i magazzini sono il luogo di attesa per i prodotti dal punto di origine a quello di consumo, garantiscono l’immagazzinamento e lo stoccaggio della merce ed infine sono un driver fondamentale per ridurre l’incertezza. Tra le attività più costose si colloca il prelievo frazionato della merce o order picking, responsabile del 55% dei costi operativi logistici. Nell'ambito Ocem è stato implementato un progetto per la riduzione dei tempi di prelievo ispirandosi a modelli nati in letteratura. Il progetto inizialmente è stato testato su una linea pilota a bassi volumi per monitorare i possibili vantaggi. Una volta confermata la riduzione effettiva dei tempi di prelievo, il progetto è stato replicato con le opportune modifiche sulle restanti linee di assemblaggio raggiungendo incrementi di efficienza significativi. Il parametro adottato come performance index è stata la riduzione percentuale del tempo di prelievo dall’as-is al to-be.

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The present research aims to analyse the impact of corporate governance and cultural dimensions in dividend policy. The corporate governance and dividend policy have a close relationship, in that both are evidenced in literature to mitigate agency problems. Cultural factors are also related to agency problems. The existence of agency problems and their solutions differs across countries and it is related to the implementation of the mechanisms of governance. So, cultural factors may have influence on corporate governance and dividend policy. Our sample consists in 1 232 companies belonging to the main indices of 38 countries classified as emerging or developed. To measure the quality of firm level corporate governance, we use the ASSET4 Corporate Governance Performance Index, developed by Thomson Reuters, and as proxy of culture we use three cultural dimensions developed by Geert Hofstede, namely uncertainty avoidance, masculinity and indulgence. We obtained significant empirical evidence that firms with high quality of corporate governance pay higher dividends. With regard to cultural factors, we confirm that in countries with high levels of masculinity and uncertainty avoidance, the dividend payout ratio is lower. On the other hand, countries with high level of indulgence have higher dividend payout ratio. However, we verify that the impact of cultural effects is minimized when the firms have a high quality level of corporate governance. Additionally, we found that the impact of corporate governance and cultural factors in dividend policy differs when dealing with emerging or developed countries.

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Load frequency Control (LFC) is used for many years as part of Automatic Generation Control (AGC) in power system around the world. In a mixed power system, it is usual to find an area regulated by hydro generation interconnected to another area regulated by thermal generation or in combination of both. In the following study, performance of AGC for Thermal, Hydro and Thermal turbine based power system is examined, including how frequency bias setting influences AGC responseand inadvertent interchange. Control performance analysis of three area interconnected systems is simulated and studied through Matlab Simulink software. Integral square error and Integral time absolute error has been used as performance criterion. It is shown that integral timeabsolute error (ITAE) as performance index leads to faster optimization of controller gain.

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El objetivo de esta investigación se centra en el análisis de los factores que inciden con mayor frecuencia en el fracaso de los emprendimientos en Colombia, y considerar su proximidad con el concepto de logística como actividad elemental para el desarrollo de los emprendimientos en el país. La finalidad de esta investigación es mostrar que los patrones que conducen al fracaso, los cuales están catalogados dentro de las categorías financiera, organizacional, operativa, de entorno, de mercadeo o de recursos humanos, tienen un nivel de incidencia dentro del fracaso, por lo cual, se puede ejecutar un análisis que permita demostrar el orden de las seis categorías mencionadas según su impacto dentro del fracaso y a su vez, brindar estrategias que permitan reducir las posibilidades de fracasar en los emprendimientos.

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The trend of diminished funding, demands for greater efficiency and higher public accountability have led to a rapid expansion of interest in the bibliometric assessment of research performance of universities. A pilot research is conducted to provide a preliminary overview of the research performance of the building and construction schools or departments through the analysis of bibliometric indicators including the journal impact factor (JIF) published by Institute for Scientific Information (ISI). The suitability of bibliometric evaluation approaches as a measure of research quality in building and construction management research field is discussed.

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Abstract Purpose – The purpose of this paper is to identify stakeholders’ expectations of information to be conveyed in local authorities’ annual reports and to develop an index of best practice performance reporting. Design/methodology/approach – The paper describes the development of a disclosure index emphasizing the public interest aspect of reporting and the need to provide relevant and meaningful information to stakeholders. The index was crafted from a public accountability perspective and based on the expectations of stakeholders as reconciled and validated by a Delphi panel of experts. Findings – The wide scope of information that was dentified as being important for disclosure by local authorities is consistent with the public accountability paradigm which requires the reporting of comprehensive information (both financial and non financial), about the condition, performance, activities and progress of the entity. Originality/value – The research posits a model of best practice performance reporting for Malaysian, and other, local authorities to meet the need for greater accountability by these entities.