Tendencias de los procesos de evaluación de la calidad de la educación superior en Europa.

Este artículo pretende dar cuenta de las principales tendencias acerca de los procesos de evaluación y acreditación de la calidad de los sistemas de educación superior europeos, a partir del denominado Proceso de Bologna. Concibiendo el tema de la calidad como un concepto clave en tanto se considera un bien público y como un factor determinante de la competitividad de un país, nos proponemos dar cuenta de las tendencias en este campo y plantear algunas conclusiones que contribuyan al análisis y el debate

Encoderless Gimbal Calibration of Dynamic Multi-Camera Clusters

Dynamic Camera Clusters (DCCs) are multi-camera systems where one or more cameras are mounted on actuated mechanisms such as a gimbal. Existing methods for DCC calibration rely on joint angle measurements to resolve the time-varying transformation between the dynamic and static camera. This information is usually provided by motor encoders, however, joint angle measurements are not always readily available on off-the-shelf mechanisms. In this paper, we present an encoderless approach for DCC calibration which simultaneously estimates the kinematic parameters of the transformation chain as well as the unknown joint angles. We also demonstrate the integration of an encoderless gimbal mechanism with a state-of-the art VIO algorithm, and show the extensions required in order to perform simultaneous online estimation of the joint angles and vehicle localization state. The proposed calibration approach is validated both in simulation and on a physical DCC composed of a 2-DOF gimbal mounted on a UAV. Finally, we show the experimental results of the calibrated mechanism integrated into the OKVIS VIO package, and demonstrate successful online joint angle estimation while maintaining localization accuracy that is comparable to a standard static multi-camera configuration.Comment: ICRA 201

Fractal analysis of weld defect patterns obtained by radiographic tests

This paper presents a fractal analysis of radiographic patterns obtained from specimens with three types of inserted welding defects: lack of fusion, lack of penetration, and porosity. The study focused on patterns of carbon steel beads from radiographs of the International Institute of Welding (IIW). The radiographs were scanned using a greyscale with 256 levels, and the fractal features of the surfaces constructed from the radiographic images were characterized by means of Hurst, detrended-fluctuation, and minimal-cover analyses. A Karhunen-Loeve transformation was then used to classify the curves obtained from the fractal analyses of the various images, and a study of the classification errors was performed. The obtained results indicate that fractal analyses can be an effective additional tool for pattern recognition of weld defects in radiographic tests.Comment: 7 pages, 2 figures. To appear AIP Conference Proceedings - QNDE 200

Solving the time-dependent Schr\"odinger equation with absorbing boundary conditions and source terms in Mathematica 6.0

In recent decades a lot of research has been done on the numerical solution of the time-dependent Schr\"odinger equation. On the one hand, some of the proposed numerical methods do not need any kind of matrix inversion, but source terms cannot be easily implemented into this schemes; on the other, some methods involving matrix inversion can implement source terms in a natural way, but are not easy to implement into some computational software programs widely used by non-experts in programming (e.g. Mathematica). We present a simple method to solve the time-dependent Schr\"odinger equation by using a standard Crank-Nicholson method together with a Cayley's form for the finite-difference representation of evolution operator. Here, such standard numerical scheme has been simplified by inverting analytically the matrix of the evolution operator in position representation. The analytical inversion of the N x N matrix let us easily and fully implement the numerical method, with or without source terms, into Mathematica or even into any numerical computing language or computational software used for scientific computing.Comment: 15 pages, 7 figure

Tuning hole mobility in InP nanowires

Transport properties of holes in InP nanowires were calculated considering electron-phonon interaction via deformation potentials, the effect of temperature and strain fields. Using molecular dynamics, we simulate nanowire structures, LO-phonon energy renormalization and lifetime. The valence band ground state changes between light- and heavy-hole character, as the strain fields and the nanowire size are changed. Drastic changes in the mobility arise with the onset of resonance between the LO-phonons and the separation between valence subbands.Comment: 4 pages, 4 figure

Supporting the Development of Science Teacher Leaders - Where Do We Begin?

This conference paper was presented at the annual meeting of the Association for Science Teacher Education in Minneapolis, MN, in January 2011.Teacher leadership has been recognized as a necessary ingredient to support educational reform efforts. Leaders provide the needed expertise to ensure reforms are successful in promoting student learning. The overarching goal of the Leadership in Freshman Physics program is to support a cadre of teachers-leaders who will become advocates for “Physics First” by developing their knowledge of physics content and research-based pedagogy. In order to support teachers in developing the knowledge, skills, and dispositions for effective leadership, it is important to first understand their initial views of teacher leadership and their prior leadership experiences. In this paper we present results from the initial phase of our multi-year research study in which we examine teacher' past leadership experiences, definitions of teacher leadership, and views of themselves as leaders. Participants include a cohort of 36 teachers participating in the program, each of whom has committed to teaching a year‐long freshman physics course at their school. Our findings indicate teachers' definitions of leadership are relatively narrow, and often confined to formal leadership roles. Though teachers participate in numerous leadership activities, they don't explicitly consider these to be leadership. Implications for addressing teachers' conceptions through professional development are shared

Análise microbiológica e estabilidade de farinha de cascas e albedo de maracujá e arroz pelo processo de extrusão termoplástica.

Edição dos Resumos do VI Congresso Latinoamericano e XII Congresso Brasileiro de Higienistas de Alimentos, II Encontro Nacional de Vigilância das Zoonoses, IV Encontro do Sistema Brasileiro de Inspeção de Produtos de Origem Animal, Gramado, abr. 2013

Composição centesimal e minerais de farinha extrudada de cascas e albedo de maracujá e arroz.

Edição dos Resumos do VI Congresso Latinoamericano e XII Congresso Brasileiro de Higienistas de Alimentos, II Encontro Nacional de Vigilância das Zoonoses, IV Encontro do Sistema Brasileiro de Inspeção de Produtos de Origem Animal, Gramado, abr. 2013

Temperature tuning from direct to inverted bistable electroluminescence in resonant tunneling diodes

The authors are grateful for financial support by the BMBF via national project EIPHRIK (FKZ: 13N10710), the European Union (FPVII (2007-2013) under grant agreement no. 318287 LANDAUER), and the Brazilian Agencies CNPq and CAPES. S. H. gratefully acknowledges support by the Royal Society and the Wolfson Foundation.We study the electroluminescence (EL) emission of purely n-doped resonant tunneling diodes in a wide temperature range. The paper demonstrates that the EL originates from impact ionization and radiative recombination in the extended collector region of the tunneling device. Bistable current-voltage response and EL are detected and their respective high and low states are tuned under varying temperature. The inversion bistability of the EL intensity can be switched from direct to inverted with respect to the tunneling current and the optical on/off ratio can be enhanced with increasing temperature. One order of magnitude amplification of the optical on/off ratio can be attained compared to the electrical one. Our observation can be explained by an interplay of moderate peak-to-valley current ratios, large resonance voltages, and electron energy loss mechanisms and thus could be applied as an alternative route towards optoelectronic applications of tunneling devices.PostprintPeer reviewe