962 resultados para educational content


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This paper presents a novel approach using combined features to retrieve images containing specific objects, scenes or buildings. The content of an image is characterized by two kinds of features: Harris-Laplace interest points described by the SIFT descriptor and edges described by the edge color histogram. Edges and corners contain the maximal amount of information necessary for image retrieval. The feature detection in this work is an integrated process: edges are detected directly based on the Harris function; Harris interest points are detected at several scales and Harris-Laplace interest points are found using the Laplace function. The combination of edges and interest points brings efficient feature detection and high recognition ratio to the image retrieval system. Experimental results show this system has good performance. © 2005 IEEE.

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Using spcctroscopic ellipsometry (SE), we have measured the optical properties and optical gaps of a series of amorphous carbon (a-C) films ∼ 100-300 Å thick, prepared using a filtered beam of C+ ions from a cathodic arc. Such films exhibit a wide range of sp3-bonded carbon contents from 20 to 76 at.%, as measured by electron energy loss spectroscopy (EELS). The Taue optical gaps of the a-C films increase monotonically from 0.65 eV for 20 at.% sp3 C to 2.25 eV for 76 at.% sp3 C. Spectra in the ellipsometric angles (1.5-5 eV) have been analyzed using different effective medium theories (EMTs) applying a simplified optical model for the dielectric function of a-C, assuming a composite material with sp2 C and sp3 C components. The most widely used EMT, namely that of Bruggeman (with three-dimensionally isotropic screening), yields atomic fractions of sp3 C that correlate monotonically with those obtained from EELS. The results of the SE analysis, however, range from 10 to 25 at.% higher than those from EELS. In fact, we have found that the volume percent sp3 C from SE using the Bruggeman EMT shows good numerical agreement with the atomic percent sp3 C from EELS. The SE-EELS discrepancy has been reduced by using an optical model in which the dielectric function of the a-C is determined as a volume-fraction-weighted average of the dielectric functions of the sp2 C and sp3 C components. © 1998 Elsevier Science S.A.

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The dependence of microstructure and thermal stability on Fe content of bulk Nd60Al10Ni10Cu20-xFex (0 less than or equal to x less than or equal to 20) metallic glasses is investigated by means of differential scanning calorimetry (DSC), X-ray diffraction (XRD) and high-resolution transmission electron micrograph (HRTEM). All samples exhibit typical amorphous feature under the detect limit of XRD, however, HRTEM results show that the microstructure of Nd60Al10Ni10Cu20-xFex alloys changes from a homogeneous amorphous phase to a composite structure consisting of clusters dispersed in amorphous matrix by increasing Fe content. Dynamic mechanical properties of these alloys with controllable microstructure are studied, expressed via storage modulus, the loss modulus and the mechanical damping. The results reveal that the storage modulus of the alloy without Fe added shows a distinct decrease due to the main a relaxation. This decrease weakens and begins at a higher temperature with increasing Fe content. The mechanism of the effect of Fe addition on the microstructure and thermal stability in this system is discussed in terms of thermodynamics viewpoints. (C) 2004 Elsevier B.V. All rights reserved.

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[Es]Desde este artículo se revisan diversos estudios de investigación relativos a la sublínea de formación del profesorado de educación física y deportiva, así como a la intervención docente en esta área de conocimientos. Esta sublínea se enmarca en la línea de Actividad Física y Deportes en el área de Didáctica de la Expresión Corporal. En este caso, se incluyen estudios de carácter naturalista e interpretativo, con la intención de que las personas que investigan y sus protagonistas formen parte activa en el propio proceso investigador (Bodgan y Biklen, 1982; Colás y Buendía, 1992; Goetz y Lecompte, 1988; Vázquez y Angulo, 2003). La formación del profesorado de educación física y la actividad didáctica de dicha materia, se convierten en los contenidos que concretan el proceso de la investigación. Para ello, es preciso revisar las temáticas relacionadas con: la formación inicial y permanente, planes y programas de estudio, contenidos que se enseñan y aprenden en la actividad física escolar (dentro y fuera del horario lectivo), la presencia de los valores, los diferentes elementos que constituyen los diseños curriculares, así como todo, aquello que convierte a esta disciplina en una destacada propuesta formativa y de socialización.

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[EN]This paper proposes an approach to the concept of ICT-based innovation in schools, from the perspective of the factors that facilitate the innovative use of ICT. To this end, a scale has been developed and validated to identify these factors through the participation of 195 teachers from 16 schools considered by the Basque educational authorities as innovators in ICT. The results obtained attest to the validity and reliability of both the scale and the 5 key factors that influence innovation in technology-based teaching. This factor-based structure enables a holistic view of ICT innovation in schools across 3 key areas: school context, teachers and the education authorities.

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In December 1956 the U. S. Geological Survey, in cooperation with the Florida Geological Survey and the Board of County Commissioners of Pinellas County, collected waterlevel and chloride content of water in 94 wells in Pinellas County. First sampled in 1947, resampling and reanalyzing the water from these wells was used to determine the change in the chloride content of the ground water from 1947 to 1956. The chloride content of ground water is generally a reliable indication of the contamination of ground water by sea water, as 90 percent of the dissolved solids of sea water are chloride salts. (PDF contains 15 pages.)