Phase-space analysis of wavefront coding imaging systems

We explore the use of the Radon-Wigner transform, which is associated with the fractional Fourier transform of the pupil function, for determining the point spread function (PSF) of an incoherant defocused optical system. Then we introduce these phase-space tools to analyse the wavefront coding imaging system. It is shown that the shape of the PSF for such a system is highly invarient to the defocous-related aberrations except for a lateral shift. The optical transfer function of this system is also investigated briefly from a new understanding of ambiguity function.

Prediction- and simulation-error based perceptron training: Solution space analysis and a novel combined training scheme

Previous papers have noted the difficulty in obtaining neural models which are stable under simulation when trained using prediction-error-based methods. Here the differences between series-parallel and parallel identification structures for training neural models are investigated. The effect of the error surface shape on training convergence and simulation performance is analysed using a standard algorithm operating in both training modes. A combined series-parallel/parallel training scheme is proposed, aiming to provide a more effective means of obtaining accurate neural simulation models. Simulation examples show the combined scheme is advantageous in circumstances where the solution space is known or suspected to be complex. (c) 2006 Elsevier B.V. All rights reserved.

Fractional State Space Analysis of Economy Systems

This paper examines modern economic growth according to the multidimensional scaling (MDS) method and state space portrait (SSP) analysis. Electing GDP per capita as the main indicator for economic growth and prosperity, the long-run perspective from 1870 to 2010 identifies the main similarities among 34 world partners’ modern economic growth and exemplifies the historical waving mechanics of the largest world economy, the USA. MDS reveals two main clusters among the European countries and their old offshore territories, and SSP identifies the Great Depression as a mild challenge to the American global performance, when compared to the Second World War and the 2008 crisis.

Comparison of space analysis performed on plaster vs. digital dental casts applying Tanaka and Johnston's equation

OBJETIVO: comparar medidas de tamanhos dentários, suas reprodutibilidades e a aplicação da equação de regressão de Tanaka e Johnston na predição do tamanho dos caninos e pré-molares em modelos de gesso e digital. MÉTODOS: trinta modelos de gesso foram escaneados para obtenção dos modelos digitais. As medidas do comprimento mesiodistal dos dentes foram obtidas com paquímetro digital nos modelos de gesso e nos modelos digitais utilizando o software O3d (Widialabs). A somatória do tamanho dos incisivos inferiores foi utilizada para obter os valores de predição do tamanho dos pré-molares e caninos utilizando equação de regressão, e esses valores foram comparados ao tamanho real dos dentes. Os dados foram analisados estatisticamente, aplicando-se aos resultados o teste de correlação de Pearson, a fórmula de Dahlberg, o teste t pareado e a análise de variância (p < 0,05). RESULTADOS: excelente concordância intraexaminador foi observada nas medidas realizadas em ambos os modelos. O erro aleatório não esteve presente nas medidas obtidas com paquímetro, e o erro sistemático foi mais frequente no modelo digital. A previsão de espaço obtida pela aplicação da equação de regressão foi maior que a somatória dos pré-molares e caninos presentes nos modelos de gesso e nos modelos digitais. CONCLUSÃO: apesar da boa reprodutibilidade das medidas realizadas em ambos os modelos, a maioria das medidas dos modelos digitais foram superiores às do modelos de gesso. O espaço previsto foi superestimado em ambos os modelos e significativamente maior nos modelos digitais.

Space analysis of water erosion in the red-yellow latosol under conilon coffee cultivation

This work aimed to study the space behavior of the water erosion in a red-yellow latosol. Then a study was developed in an area with colinon coffee cultivation in an Experimental Farm of Bananal do Norte of INCAPER in Cachoeiro de Itapemirim - ES. Soil samples were obtained from 0,0 to 0,20 m depth in an irregular grid with 109 samples. The analyzed variables were granulometric fractions, erodibility (K), natural erosion potential (PNE), soil loss (A) and erosion risk (RE). All the variables showed space dependency with moderate index of space dependency and similar standard of space distribution. The soil loss is related with the space distribution of the granulometric fractions.

Composition Space Analysis in the Development of Copper Molybdate Hybrids Decorated by a Bifunctional Pyrazolyl/1,2,4-Triazole Ligand

A bitopic ligand, 4-(3,5-dimethylpyrazol-4-yl)-1,2,4-triazole (Hpz-tr) (1), containing two different heterocyclic moieties was employed for the design of copper(II)–molybdate solids under hydrothermal conditions. In the multicomponent CuII/Hpz-tr/MoVI system, a diverse set of coordination hybrids, [Cu(Hpz-tr)2SO4]·3H2O (2), [Cu(Hpz-tr)Mo3O10] (3), [Cu4(OH)4(Hpz-tr)4Mo8O26]·6H2O (4), [Cu(Hpz-tr)2Mo4O13] (5), and [Mo2O6(Hpz-tr)]·H2O (6), was prepared and characterized. A systematic investigation of these systems in the form of a ternary crystallization diagram approach was utilized to show the influence of the molar ratios of starting reagents, the metal (CuII and MoVI) sources, the temperature, etc., on the reaction products outcome. Complexes 2–4 dominate throughout a wide crystallization range of the composition triangle, while the other two compounds 5 and 6 crystallize as minor phases in a narrow concentration range. In the crystal structures of 2–6, the organic ligand behaves as a short [N–N]-triazole linker between metal centers Cu···Cu in 2–4, Cu···Mo in 5, and Mo···Mo in 6, while the pyrazolyl function remains uncoordinated. This is the reason for the exceptional formation of low-dimensional coordination motifs: 1D for 2, 4, and 6 and 2D for 3 and 5. In all cases, the pyrazolyl group is involved in H bonding (H-donor/H-acceptor) and is responsible for π–π stacking, thus connecting the chain and layer structures in more complicated H-bonding architectures. These compounds possess moderate thermal stability up to 250–300 °C. The magnetic measurements were performed for 2–4, revealing in all three cases antiferromagnetic exchange interactions between neighboring CuII centers and long-range order with a net moment below Tc of 13 K for compound 4.

Phase-space analysis of bosonic spontaneous emission

We present phase-space techniques for the modelling of spontaneous emission in two-level bosonic atoms. The positive-P representation is shown to give a full and complete description within the limits of our model. The Wigner representation, even when truncated at second order, is shown to need a doubling of the phase-space to allow for a positive-definite diffusion matrix in the appropriate Fokker-Planck equation and still fails to agree with the full quantum results of the positive-P representation. We show that quantum statistics and correlations between the ground and excited states affect the dynamics of the emission process, so that it is in general non-exponential. (c) 2005 Elsevier B.V. All rights reserved.

From filters to features:Scale-space analysis of edge and blur coding in human vision

To make vision possible, the visual nervous system must represent the most informative features in the light pattern captured by the eye. Here we use Gaussian scale-space theory to derive a multiscale model for edge analysis and we test it in perceptual experiments. At all scales there are two stages of spatial filtering. An odd-symmetric, Gaussian first derivative filter provides the input to a Gaussian second derivative filter. Crucially, the output at each stage is half-wave rectified before feeding forward to the next. This creates nonlinear channels selectively responsive to one edge polarity while suppressing spurious or "phantom" edges. The two stages have properties analogous to simple and complex cells in the visual cortex. Edges are found as peaks in a scale-space response map that is the output of the second stage. The position and scale of the peak response identify the location and blur of the edge. The model predicts remarkably accurately our results on human perception of edge location and blur for a wide range of luminance profiles, including the surprising finding that blurred edges look sharper when their length is made shorter. The model enhances our understanding of early vision by integrating computational, physiological, and psychophysical approaches. © ARVO.

El cambio de valores para la mejora de las estrategias de aprendizaje y el rendimiento académico.

Analizar la relación entre los valores personales del alumnado de BUP y sus concepciones referidas al aprendizaje, sus conductas de estudio y su rendimiento académico. Aplicar el método de Autoconfrontación de valores para mejorar los hábitos y estrategias de aprendizaje del alumnado de BUP. Estudio 1: 325 alumnos-as, 179 de primero de BUP y 146 de segundo, pertenecientes a institutos de Bachillerato de la zona norte, centro y sus de Madrid. Estudio 2: 301 alomnos-as de segfundo de BUP, 157 del grupo experimental y 144 del de control, pertenecientes a centros de Bachillerato de la zona norte, centro y sur de Madrid. Estudio 1: se realiza un estudio correlacional en el que se analiza la relación entre los valores personales del alumnado y los determinantes del rendimiento académico. Se procede a la aplicación del Cuestionario de Valores de Schwartz (CVS), analizando los datos obtenidos según el procedimiento de análisis multidimensional SSA (Smallest Space Analysis). Se aplica el Cuestionario de Estrategias de Aprendizaje, Hábitos de Estudio y Satisfacción Académica (CEAYS), reduciendo los datos obtenidos, mediante análisis factorial con rotación varimax y un índice de fiabilidad, a un conjunto de variables compuestas. Estudio 2: se aplica un cuestionario inicial a la muestra y se procede a la puesta en práctica, con el grupo experimental, de la intervención educativa Autoconfrontación de valores. Tras dicha aplicación, se realiza un cuestionario al grupo experimental. Cuestionario de Valores de Schwartz (CVS), Cuestionario de Estrategias de Aprendizaje, Hábitos de Estudio y Satisfacción Académica (CEAYS). Porcentajes, rotación varimax, análisis multidimensional SSA. El rendimiento académico se relaciona con las actitudes hacia uno mismo y hacia el aprendizaje, así como con las conductas de uso de materiales y las de estudio. El autoconcepto y la autoestima académica general correlacionan con la frecuencia de las conductas de estudio y con el rendimiento académico. Las conductas concretas de estudio no se relacionan significativamente de manera directa con el rendimiento académico. De acuerdo con la teoría motivacional de Schwartz, se observa que el alumnado organiza sus valores en 10 tipos: Universalismo, Benevolencia, Conformidad, Seguridad, Poder, Logro, Hedonismo, Estimulación y Autodirección. Se observa que el estudio parece ser percibido por el alumnado de BUP como una actividad social normativamente impuesta. Tras la intervención educativa se observa una mejora moderada en el rendimiento académico y el efecto de la Autoconfrontación no depende del rendimiento académico previo, lo que significa que la intervención contribuye de igual forma a los diferentes colectivos estudiantiles. Considerando la eficacia de la intervención de la Autoconfrontación en relación a su coste y al esfuerzo invertido, esta intervención se revela como altamente eficaz para la mejora del rendimiento académico del alumnado.

Representação social do ensinar: a dimensão pedagógica do habitus professoral

Teaching is an activity inherent to the human condition. Historically, from the institutionalization of education, the key role to pursue that activity has been attributed to the teacher, who is required to adapt to the demands of each historical conjuncture. Currently, according to the new paradigmatic requirements, the teacher must possess various skills in order to handle the complex and challenging act of teaching. Assuming the existence of a gap between what the State and the scientific discourse recommend the teacher act upon in the classroom, a decision was made to identify the configuration and structure of social representation in the act of teaching, put forth by elementary school teachers in the public schools of Natal, RN, Brazil. Therefore, the research relied on the theoretical model developed by Domingos Sobrinho (1998, 2000, 2003), which articulates the praxeology of Pierre Bourdieu with the theory of social representations of Serge Moscovici (1978). It was intended to demonstrate how teachers habitus, in its due historical context, directs the construction of social representations in the act of teaching which guides the actions of the teacher, particularly in the classroom context. At the methodological level, the following methods and techniques were used: bibliographic and documentary review in order to identify the scientific discourse on the subject matter and the official parameters of educational regulation and the act of teaching; the Procedure of Multiple Classifications PMC in order to capture the configuration and structure of the representational content in focus, the direct observation of the classroom to identify in actual terms the social representation as "guide to action" as the theory preaches. From the standpoint of the analysis, quantitative data were analysed through Multidimensional Scaling MDS, covering in this study the Multidimensional Scale Analysis MSA and Smallest Space Analysis SSA; and non-parametric statiscal techniques. Additional data of qualitative value had to undergo categorical content analysis. It was then concluded that the teachers investigated guided themselves by social representation, the product of collectively constructed and shared assumptions about the act of teaching, forming a synthesis of different sources of information and knowledge acquirement, involving elements of common sense, religious habitus, pedagogic models considered outdated, the agencies responsible for teacher training and the hegemonic discourse about education today

O fazer docente: representações sociais de alunos de curso de pedagogia da UFRN

Cuando consideramos los procesos de formación del profesorado pensamos en los nuevos conocimientos que podrían ser aprendidos por los estudiantes involucrados, centrándose en el debate de cuales contenidos y conocimientos deben estar presentes en la formación que se desea para estos profesionales. El propósito de esta investigación es analizar el tema desde un ángulo diferente, invertido, desde la perspectiva de los estudiantes de pedagogía en la formación inicial, mirando cómo utilizan los conocimientos adquiridos durante la licenciatura, en un proceso de construcción y reconstrucción de los conocimientos que empiezan a permear a sus prácticas pedagógicas. Dado este marco, nuestro propósito ha sido estudiar los elementos de construcción de la identidad de los futuros licenciados en Pedagogía por la UFRN, intentando caracterizar las representaciones sociales expresadas por estos estudiantes acerca del trabajo del maestro, a través de la identificación de los elementos definidores de las dichas representaciones (conocimiento del contenido de estas) y la comprensión de la forma dinámica de organización de tales elementos. Tomamos como referencia la teoría de las representaciones sociales (MOSCOVICI, 1978), que proporciona una idea de cómo los futuros docentes construyen sus representaciones acerca de los objetos de conocimiento que rodean la formación docente. Participaron del estudio 120 estudiantes de la graduación en Pedagogía, cuándo nos acercamos a los contenidos simbólicos traídos por ellos utilizando el Procedimiento de Múltiples Clasificaciones (PMC) como el enfoque metodológico. El material incautado por tal procedimiento se sometió a análisis multidimensional (Smallest Space Analysis (SSA) y Multidimensional Scalogram Analysis (MAS)) y de contenido, con la intención de un entendimiento más amplio de las dimensiones simbólicas. Los resultados de la investigación mostraron las siguientes dimensiones: la afectiva, con el nombramiento de las características necesarias a construcción simbólica del maestro; la formativa, que resalta los elementos necesarios para una enseñanza profesional; el aspecto ético y profesional, que aborda los elementos necesarios para el desempeño docente, en la perspectiva de transformación social mediante la educación; y la dimensión conflictiva, poniendo de relieve las dificultades del trabajo docente. Por lo tanto, estos aspectos muestran que la representación de ser maestro, construida por los estudiantes en la formación, parece constar de diferentes matices, articuladas y complementares, que dan sentido a la profesión, lo que justificará la práctica diaria de los futuros profesionales