Detección y localización de superficies en un ambiente 3D a través de un solo sensor y casquetes esféricos ultrasónicosFabio T Moreno-Ortiz 1 , Eduardo Castillo-Castañeda 2 , and Antonio Hernández-Zavala 3 ABSTRACTIn this paper, an ultrasonic arc map method for flat mapping is extended to three-dimensional space replacing the circumference arcs by spherical caps. An enclosed environment is scanned by employing a single ultrasonic device. The range, position, and orientation of the transducer are used to digitize the uncertainty caps and place them in a three-dimensional map. Through the spatial voting method, the generated voxels are elected in order to distinguish those which mark the true position of an obstacle and discard those that are produced by cross talk, noise, fake ranges, and angular resolution. The results show that it is possible to obtain sufficient information to build a three-dimensional map for navigation by employing inexpensive sensors and a low power data processing.Keywords: Ultrasonic arc map, sonar resolution, SLAM, Bresenham algorithm, voxelized spherical cap, beam pattern, spatial voting. RESUMENEn este artículo, un método de mapa de arcos ultrasónicos para mapeo plano es extendido al espacio tridimensional, remplazando los arcos de circunferencia por casquetes esféricos. Un ambiente cerrado es explorado empleando solo un dispositivo ultrasónico. La distancia, posición y orientación del transductor son utilizadas para digitalizar casquetes de incertidumbre y colocarlos en un mapa tridimensional. A través del método de votación espacial, los voxeles generados son elegidos con el propósito de distinguir aquellos que marcan la posición real de un obstáculo y descartar aquellos producidos por diafonía, ruido, lecturas falsas y la resolución angular. Los resultados muestran que es posible obtener suficiente información para construir un mapa tridimensional para navegación mediante el empleo de sensores de bajo costo y un procesamiento de datos de baja potencia.Palabras clave: Mapa de arco ultrasónico, resolución del sonar, SLAM, algoritmo de Bresenham, casquete esférico voxelizado, patrón de dispersión, votación espacial.

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Mexico is adopting the competence-based model for education improvement. One of the major problems is to quantify the results of assessment to provide a grade considering subjective data. It commonly results in the assignation of an arbitrary grade which is estimated by the experience of the teacher using the evidence from the students. This paper presents a fuzzy system for calculating the grade assignment at undergraduate courses considering the student competences. The obtained results are compared against the grades that are calculated with the traditional average method and those obtained with the pass-fail checklists method.