Analyzing interference between RGB-D cameras for human motion tracking

Multi-camera RGB-D systems are becoming popular as sensor setups in Computer Vision applications but they are prone to cause interference between them, compromising their accuracy. This paper extends previous works on the analysis of the noise introduced by interference with new and more realistic camera configurations and different brands of devices. As expected, the detected noise increases as distance and angle grows, becoming worse when interference is present. Finally, we evaluate the effectiveness of the proposed solutions of using DC vibration motors to mitigate them. The results of this study are being used to assess the effect of interference when applying these setups to human motion tracking.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Plan Propio de Investigación de la UMA. Junta de Andalucía, proyecto TEP2012-53

Design and Implementation of a HardwareModule for MIMO Decoding in a 4G Wireless Receiver

Future 4th Generation (4G) wireless multiuser communication systems will have to provide advanced multimedia services to an increasing number of users, making good use of the scarce spectrum resources. Thus, 4G systemdesign should pursue both highertransmission bit rates and higher spectral efficiencies. To achieve this goal,multiple antenna systems are called to play a crucial role. In this contribution we address the implementation in FPGAs of a multiple-input multiple-output (MIMO) decoder embedded in a prototype of a 4G mobile receiver. This MIMO decoder is part of a multicarrier code-division multiple-access (MC-CDMA) radio system, equipped with multiple antennas at both ends of the link, that is able to handle up to 32 users and provides raw transmission bit-rates up to 125 Mbps. The task of the MIMO decoder is to appropriately combine the signals simultaneously received on all antennas to construct an improved signal, free of interference, from which to estimate the transmitted symbols. A comprehensive explanation of the complete design process is provided, including architectural decisions, floating-point to fixedpoint translation, and description of the validation procedure. We also report implementation results using FPGA devices of the Xilinx Virtex-4 family

ED-BioRob: A Neuromorphic Robotic Arm With FPGA-Based Infrastructure for Bio-Inspired Spiking Motor Controllers

Compared to classic robotics, biological nervous systems respond to stimuli in a fast and efficient way regarding the body motor actions. Decision making, once the sensory information arrives to the brain, is in the order of ms, while the whole process from sensing to movement requires tens of ms. Classic robotic systems usually require complex computational abilities. Key differences between biological systems and robotic machines lie in the way information is coded and transmitted. A neuron is the "basic" element that constitutes biological nervous systems. Neurons communicate in an event-driven way through small currents or ionic pulses (spikes). When neurons are arranged in networks, they allow not only for the processing of sensory information, but also for the actuation over the muscles in the same spiking manner. This paper presents the application of a classic motor control model (proportional-integral-derivative) developed with the biological spike processing principle, including the motor actuation with time enlarged spikes instead of the classic pulse-width-modulation. This closed-loop control model, called spike-based PID controller (sPID), was improved and adapted for a dual FPGA-based system to control the four joints of a bioinspired light robot (BioRob X5), called event-driven BioRob (ED-BioRob). The use of spiking signals allowed the system to achieve a current consumption bellow 1A for the entire 4 DoF working at the same time. Furthermore, the robot joints commands can be received from a population of silicon-neurons running on the Dynap-SE platform. Thus, our proposal aims to bridge the gap between a general purpose processing analog neuromorphic hardware and the spiking actuation of a robotic platform

New cementitious materials based on alkali-activated fly ash: performance at high temperatures

This paper reports on a comparative study of the mechanical performance at different temperatures of a commercial Portland cement, used as a control, and a new cementitious material made from an 8M-NaOH activated fly ash and containing no OPC. Two types of mechanical tests were conducted: (i) high temperature mechanical tests, to determine the strength and fracture toughness of the two materials between 251 and 6001C, and (ii) post-thermal treatment tests, to evaluate the residual strength after 1 h of exposure to different temperatures (2001, 4001, 6001, 8001, and 10001C). In both cases, the results showed that the new cementitious material performed significantly better at high temperatures than the Portland cement control. Differential thermogravimetry (DTG)/TG, Fourier transform infrared (FTIR), and X-ray diffraction analyses were also conducted to analyze the mineralogical and microstructural variations taking place in the material as a result of high temperature exposure. The results of these tests were correlated with the mechanical behaviour observed

Bio-inspired computational memory model of the Hippocampus: an approach to a neuromorphic spike-based Content-Addressable Memory

The brain has computational capabilities that surpass those of modern systems, being able to solve complex problems efficiently in a simple way. Neuromorphic engineering aims to mimic biology in order to develop new systems capable of incorporating such capabilities. Bio-inspired learning systems continue to be a challenge that must be solved, and much work needs to be done in this regard. Among all brain regions, the hippocampus stands out as an autoassociative short-term memory with the capacity to learn and recall memories from any fragment of them. These characteristics make the hippocampus an ideal candidate for developing bio-inspired learning systems that, in addition, resemble content-addressable memories. Therefore, in this work we propose a bio-inspired spiking content-addressable memory model based on the CA3 region of the hippocampus with the ability to learn, forget and recall memories, both orthogonal and non-orthogonal, from any fragment of them. The model was implemented on the SpiNNaker hardware platform using Spiking Neural Networks. A set of experiments based on functional, stress and applicability tests were performed to demonstrate its correct functioning. This work presents the first hardware implementation of a fully-functional bio-inspired spiking hippocampal content-addressable memory model, paving the way for the development of future more complex neuromorphic systems.Comment: 15 pages, 5 figures, journal, Spiking Neural Networ

Comportamiento mecánico a altas temperaturas de cementos de ceniza volante activados alcalinamente

En este trabajo se realiza un estudio comparativo del comportamiento mecánico, en función de la temperatura, entre un cemento Portland comercial, utilizado de referencia y dos nuevos materiales cementantes. Los ensayos realizados se han centrado en muestras de cemento portland , muestras de cenizas volantes activadas con un 100% de silicato sódico y muestras con un 70% de ceniza y un 30% de cemento activadas con un activador en estado sólido.Se realizaron dos tipos de ensayos: 1) post tratamiento térmico, donde se evaluó la resistencia mecánica residual tras una hora de exposición térmica a diferentes temperaturas, y 2) ensayos mecánicos a altas temperaturas , donde se determino el comportamiento mecánico y la tenacidad a la fractura a distintas temperaturas. Técnicas de Rayos X y microscopía electrónica de barrido han sido utilizadas para analizar las variaciones microestructurales en los materiales, como consecuencia de la exposición a altas temperaturas

Development of a computing application for the dimensioning of deployment mechanisms in artificial satellites - Desarrollo de una Aplicación Informática para el Dimensionado de Mecanismos de Despliegue en Satélites Artificiales

Los satélites artificiales a menudo deben desplegar instrumentos una vez puestos en órbita. El diseño de los mecanismos encargados de llevar a cabo este cometido es crítico, ya que un despliegue incorrecto implicaría en muchos casos la pérdida del satélite. En el caso de las antenas, un despliegue incorrecto o descontrolado podría tener como consecuencia impactos excesivamente altos que podrían producir daños estructurales, cambios de actitud del satélite, des alineamiento de las mismas, etc. Los mecanismos encargados de desplegar las antenas usualmente están compuestos por un muelle pretensado que aporta el par necesario para desplegar la misma y un sistema de amortiguación encargado de evitar que desarrolle velocidades excesivamente altas. Basándose en este contexto, se han desarrollado dos aplicaciones informáticas que, partiendo de las características de un despliegue definido por el usuario, son capaces de realizar simulaciones del mismo utilizando distintos mecanismos de despliegue, obtenidos al variar las características del muelle o el sistema de amortiguación, aportando información del comportamiento cinemático y dinámico del elemento a desplegar en cada caso, y clasificando cada uno de los posibles mecanismos de acuerdo con los requisitos de diseño impuestos por las normas ECSS, que son de obligado cumplimiento para la Agencia Espacial Europea

The dilemmas of educational services to newly arrived immigrant students. A comparative study of Andalusia (ATAL) and Madrid (bridge classrooms) models

ArtículoEn este trabajo comparamos las Aulas Temporales de Adaptación Lingüística (ATAL) andaluzas y las Aulas de Enlace (AE) madrileñas. Ambas medidas se han puesto en marcha para dar respuesta a las necesidades de los alumnos extranjeros recién llegados que no tienen un suficiente dominio del español. No obstante la coincidencia de sus objetivos, las diferencias organizativas y de funcionamiento suscitan el análisis que presentamos, basando nuestras reflexiones en los resultados arrojados por las investigaciones que los autores hemos llevado a cabo en ambas comunidades autónomas. En concreto, centramos nuestro análisis en cuatro puntos que a nuestro parecer constituyen los dilemas básicos en el planteamiento de este tipo de aulas, con el objetivo de contribuir a la mejora de las medidas de apoyo lingüístico a los alumnos extranjeros recién llegados: a) El número de horas que los alumnos extranjeros asisten al aula lingüística, es decir, cuánto tiempo están separados del resto de alumnos de su curso.a) El tipo de apoyo que reciben, dentro o fuera del aula ordinaria. b) El currículum propio de estas aulas. En qué medida se centra sólo en lo lingüístico o se trabajan también contenidos de las asignaturas ordinarias. c) El papel que ocupan las culturas y lenguas de origen del alumnado, si se tienen en cuenta y se toman como soporte y apoyo o se obvian

Mechanical behavior of alkali-cement as function of the temperature.

This investigation reports on a comparative study of the mechanical behavior at different temperatures of three different alkali-activated fly ash pastes chemically activated using sodium silicate. A control Portland cement (OPC) was used as a reference. In an attempt to simulate the conditions prevailing in the event of accidental fire, post-thermal mechanical tests were performed to determine the residual strength. It has therefore been established that FA based cements can be fabricated for construction purposes and these materials have great potential for fire resistance applications