972 resultados para Delphi Method
Resumo:
We present an analytical procedure to perform the local noise analysis of a semiconductor junction when both the drift and diffusive parts of the current are important. The method takes into account space-inhomogeneous and hot-carriers conditions in the framework of the drift-diffusion model, and it can be effectively applied to the local noise analysis of different devices: n+nn+ diodes, Schottky barrier diodes, field-effect transistors, etc., operating under strongly inhomogeneous distributions of the electric field and charge concentration
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A simple and rapid precipitation titration method was developed and validated to determine sulfate ion content in indinavir sulfate raw material. 0.1 mol L-1 lead nitrate volumetric solution was used as titrant employing potentiometric endpoint determination using a lead-specific electrode. The United States Pharmacopoeia Forum indicates a potentiometric method for sulfate ion quantitation using 0.1 mol L-1 lead perchlorate as titrant. Both methods were validated concerning linearity, precision and accuracy, yielding good results. The sulfate ion content found by the two validated methods was compared by the statistical t-student test, indicating that there was no statistically significant difference between the methods.
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The spectrophotometric determination of Cd(II) using a flow injection system provided with a solid-phase reactor for cadmium preconcentration and on-line reagent preparation, is described. It is based on the formation of a dithizone-Cd complex in basic medium. The calibration curve is linear between 6 and 300 µg L-1 Cd(II), with a detection limit of 5.4 µg L-1, an RSD of 3.7% (10 replicates in duplicate) and a sample frequency of 11.4 h-1. The proposed method was satisfactorily applied to the determination of Cd(II) in surface, well and drinking waters.
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Este estudio aborda un doble objetivo: a) conocer si existe progresión signi+cativa entre tres valores correspondientes al índice de Borg elicitados por jóvenes deportistas con relación a tres actividades de intensidad creciente; b) analizar la relación existente entre el índice de masa corporal (IMC) de los participantes con los valores de frecuencia cardíaca (FC) y la percepción de intensidad del esfuerzo (RPE). Método: Treinta y cinco deportistas jóvenes con una edad media de 18 y 28 años (21±0,5), realizaron 3 actividades que exigían una intensidad creciente de ejercicio: leve, moderada y vigorosa (ACSM, 2011). Se controló la frecuencia cardíaca mediante el dispositivo telemétrico Polar Team 2 y al +nalizar las tres actividades se administró tres veces la escala de Borg para obtener la RPE para cada actividad. Se ha complementado la metodología observacional indirecta (índices de Borg) con la metodología cuasiexperimental para obtener inferencias causales mediante un diseño sincrónico de variable de asignación conocida y grupo único. Se ha realizado un análisis de regresión múltiple, considerando la FC y la RPE como variables predictoras del IMC. Resultados: la RPE es creciente, acorde a las actividades, en todos los participantes, aunque en ningún caso la tendencia es estadísticamente signi+cativa. Prácticamente la cuarta parte del IMC se puede explicar por la FC y la RPE puesto que los participantes que tienen valores más altos de FC y de índice de Borg tienen también mayores valores de IMC. Este estudio puede proporcionar una visión de evaluación integrada entre los factores IMC, FC y la RPE, que suelen investigarse de modo aislado.
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Desde el ámbito académico el auge de la Gestión de la Calidad (GC) ha sido analizadoextensamente a través de numerosos estudios de carácter empírico. Una parte importante de estos estudios han tratado de analizar cuáles han sido los principales efectos de laimplantación de estos modelos sobre los resultados o el desempeño (performance) empresarial. Hay que señalar que la mayor parte de dichos estudios son de tipo cuantitativo, basados en la utilización de encuestas dirigidas a los directivos de las empresas que han participado en el proceso de implantación. Ahora bien, el análisis de los efectos de la GC realizado de esta forma, cuenta, a nuestro entender, con una posible debilidad y distorsión metodológica al tomar sólo como base las opiniones de los directivos de las empresas involucradas en el proceso de implantación sobre los efectos del propio proceso y los resultados pueden tener cierto sesgo, tal y como ha sido subrayado por diversos investigadores (ver, por ejemplo, Wayhan et al, 2002 y Heras et al, 2002). Por estos motivos, en el estudio que aquí presentamos hemos considerado necesario utilizar una metodología que tenga en cuenta la opinión de expertos de diversa índole que tienen distintas funciones en la implantación de modelos de GC, de forma que se pueda obtener una información de interés para contrastarla y triangularizarla con la obtenida en estudios empíricos previos llevados a cabo con la metodología tradicional
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This paper describes the basis of citation auctions as a new approach to selecting scientific papers for publication. Our main idea is to use an auction for selecting papers for publication through - differently from the state of the art - bids that consist of the number of citations that a scientist expects to receive if the paper is published. Hence, a citation auction is the selection process itself, and no reviewers are involved. The benefits of the proposed approach are two-fold. First, the cost of refereeing will be either totally eliminated or significantly reduced, because the process of citation auction does not need prior understanding of the paper's content to judge the quality of its contribution. Additionally, the method will not prejudge the content of the paper, so it will increase the openness of publications to new ideas. Second, scientists will be much more committed to the quality of their papers, paying close attention to distributing and explaining their papers in detail to maximize the number of citations that the paper receives. Sample analyses of the number of citations collected in papers published in years 1999-2004 for one journal, and in years 2003-2005 for a series of conferences (in a totally different discipline), via Google scholar, are provided. Finally, a simple simulation of an auction is given to outline the behaviour of the citation auction approach
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A method is proposed for the determination of the moisture content of aromatic plants. This method is based on the co-distillation of the starting material in a modified Clevenger apparatus with four organic solvents (toluene, cyclohexane, dichloromethane and carbon tetrachloride). The results were compared with those obtained by oven drying at 105 ºC and steam distillation of the essential oil. The efficiencies of the methods were shown to be equivalent. The solvent distillation method was more practical, especially with respect to operating time (2 h).
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Chromium(III) at the ng L-1 level was extracted using partially silylated MCM-41 modified by a tetraazamacrocyclic compound (TAMC) and determined by inductively coupled plasma optical emision spectrometry (ICP OES). The extraction time and efficiency, pH and flow rate, type and minimum amount of stripping acid, and break- through volume were investigated. The method's enrichment factor and detection limit are 300 and 45.5 pg mL-1, respectively. The maximum capacity of the 10 mg of modified silylated MCM-41 was found to be 400.5±4.7 µg for Cr(III). The method was applied to the determination of Cr(III) and Cr(VI) in the wastewater of the chromium electroplating industry and in environmental and biological samples (black tea, hot and black pepper).
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In image processing, segmentation algorithms constitute one of the main focuses of research. In this paper, new image segmentation algorithms based on a hard version of the information bottleneck method are presented. The objective of this method is to extract a compact representation of a variable, considered the input, with minimal loss of mutual information with respect to another variable, considered the output. First, we introduce a split-and-merge algorithm based on the definition of an information channel between a set of regions (input) of the image and the intensity histogram bins (output). From this channel, the maximization of the mutual information gain is used to optimize the image partitioning. Then, the merging process of the regions obtained in the previous phase is carried out by minimizing the loss of mutual information. From the inversion of the above channel, we also present a new histogram clustering algorithm based on the minimization of the mutual information loss, where now the input variable represents the histogram bins and the output is given by the set of regions obtained from the above split-and-merge algorithm. Finally, we introduce two new clustering algorithms which show how the information bottleneck method can be applied to the registration channel obtained when two multimodal images are correctly aligned. Different experiments on 2-D and 3-D images show the behavior of the proposed algorithms
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This thesis was produced for the Technology Marketing unit at the Nokia Research Center. Technology marketing was a new function at Nokia Research Center, and needed an established framework with the capacity to take into account multiple aspects for measuring the team performance. Technology marketing functions had existed in other parts of Nokia, yet no single method had been agreed upon for measuring their performance. The purpose of this study was to develop a performance measurement system for Nokia Research Center Technology Marketing. The target was that Nokia Research Center Technology Marketing had a framework for separate metrics; including benchmarking for starting level and target values in the future planning (numeric values were kept confidential within the company). As a result of this research, the Balanced Scorecard model of Kaplan and Norton, was chosen for the performance measurement system for Nokia Research Center Technology Marketing. This research selected the indicators, which were utilized in the chosen performance measurement system. Furthermore, performance measurement system was defined to guide the Head of Marketing in managing Nokia Research Center Technology Marketing team. During the research process the team mission, vision, strategy and critical success factors were outlined.
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Quickremovalofbiosolidsinaquaculturefacilities,andspeciallyinrecirculatingaquaculturesystems(RAS),isoneofthemostimportantstepinwastemanagement.Sedimentationdynamicsofbiosolidsinanaquaculturetankwilldeterminetheiraccumulationatthebottomofthetank.
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Identification of clouds from satellite images is now a routine task. Observation of clouds from the ground, however, is still needed to acquire a complete description of cloud conditions. Among the standard meteorologicalvariables, solar radiation is the most affected by cloud cover. In this note, a method for using global and diffuse solar radiation data to classify sky conditions into several classes is suggested. A classical maximum-likelihood method is applied for clustering data. The method is applied to a series of four years of solar radiation data and human cloud observations at a site in Catalonia, Spain. With these data, the accuracy of the solar radiation method as compared with human observations is 45% when nine classes of sky conditions are to be distinguished, and it grows significantly to almost 60% when samples are classified in only five different classes. Most errors are explained by limitations in the database; therefore, further work is under way with a more suitable database