Una aportación a los sistemas de procesamiento de la información basados en modelos neuronales pulsantes

En este trabajo se propone e implementa un nuevo sistema de reconocimiento de sonidos basado en una cóclea artificial pulsante innovadora. Inicialmente se estudian los mecanismos clásicos de procesamiento de audio para el reconocimiento de sonidos; así como el funcionamiento del sistema auditivo humano en conjunción con los procesos neuronales del cerebro. A partir de dichos estudios, es como se proponen nuevos sistemas en lo que respecta al procesamiento de audio y reconocimiento de sonidos automático. En trabajos de investigación recientes se han desarrollado una serie de elementos neuromórficos hardware pulsantes basados en codificación AER (Address Event Representation), en esta tesis estos bloques sirven de punto de partida para la implementación de nuestro sistema de reconocimiento de sonidos. Se proponen e implementan dos sistemas: por una parte, una cóclea artificial para la obtención de las componentes de frecuencia del sonido, imitando el funcionamiento del aparato auditivo. Y por otra, un sistema de reconocimiento de patrones sonoros, obtenidos a partir de la salida generada por la cóclea artificial, inspirado en el comportamiento de las neuronas y las conexiones entre ellas. Por último, en este trabajo, se realiza un estudio exhaustivo para evaluar la eficiencia de los sistemas implementados y compararlos con los desarrollos previos

Análisis de usabilidad y utilidad de las herramientas GDUS+ y LAMS para el diseño pedagógico en un entorno de enseñanza semipresencial universitario

IMS Learning Design is a pedagogically neutral specification that allows the creation of environments and educational contents and that promotes the reusability. Furthermore, this specification allows a large range of didactic approaches. IMS Learning is particularly suitable for distance learning through electronic platforms. In addition, there is great interest in using these types of standards in face-to-face and blended learning at universities. However, there are some difficulties that must be overcome when considering these solutions in universities, for example, those related to the computing skills of potential uses, those associated to the usability of editing tools for Learning Units creation, or those linked to human resource costs… This article deals with these issues by analysing the usefulness and usability of two tools based on Learning Design, GDUS + and LAMS, to create virtual Learning Units according to specific pedagogical design approaches.IMS-Learning Design es una especificación pedagógicamente neutral que permite la creación de escenarios y contenidos educativos promoviendo la reusabilidad y permitiendo un amplio abanico de enfoques didácticos. No obstante, aún siendo especialmente adecuada para el ámbito de la educación a distancia mediante plataforma electrónica, existe también gran interés en emplear este tipo de estándares en entornos universitarios de enseñanza presencial y semi-presencial. Sin embargo, existen una serie de dificultades que deben ser superadas a la hora de plantear este tipo de soluciones en dichos entornos, entre otras de tipo cultural, asociadas con la usabilidad de herramientas de edición de Unidades de Aprendizaje, de coste en recursos humanos... En el presente artículo se van a abordar estas cuestiones mediante el análisis de la utilidad y usabilidad de dos herramientas basadas en Learning Desing, GDUS+ y LAMS, para la creación de Unidades de Aprendizaje virtuales según determinados enfoques de diseño pedagógico

Live Demonstration: Real-time neuro-inspired sound source localization and tracking architecture applied to a robotic platform

This live demonstration presents a sound source localization and tracking system implemented with Spike Signal Processing (SSP) building blocks on FPGA devices. The system architecture is based on the ability of the mammalian auditory system to locate the direction of a sound in the horizontal plane using the interaural intensity difference. We used a binaural Neuromorphic Auditory Sensor to obtain spike rates similar to those generated by the inner hair cells of the human auditory system and the component that obtains the interaural intensity difference is inspired by the lateral superior olive. The spike stream that represents the interaural intensity difference is used to turn a robotic platform towards the sound source direction. The system was tested with pure tones (1-kHz, 2.5-kHz and 5- kHz sounds) with an average error of 2.32 degrees.Ministerio de Economía y Competitividad TEC2016-77785-

Spikes Monitors for FPGAs, an Experimental Comparative Study

In this paper we present and analyze two VHDL components for monitoring internal activity of spikes fired by silicon neurons inside FPGAs. These spikes monitors encode each spike according to the Address-Event Representation, sending them through a time multiplexed digital bus as discrete events, using different strategies. In order to study and analyze their behavior we have designed an experimental scenario, where diverse AER systems have been used to stimulate the spikes monitors and collect the output AER events, for later analysis. We have applied a battery of tests on both monitors in order to measure diverse features such as maximum spike load and AER event loss due to collisions.Ministerio de Ciencia e Innovación TEC2009-10639-C04-02Ministerio de Economía y Competitividad TEC2012-37868-C04-0

On the Designing of Spikes Band-Pass Filters for FPGA

In this paper we present two implementations of spike-based bandpass filters, which are able to reject out-of-band frequency components in the spike domain. First one is based on the use of previously designed spike-based low-pass filters. With this architecture the quality factor, Q, is lower than 0.5. The second implementation is inspired in the analog multi-feedback filters (MFB) topology, it provides a higher than 1 Q factor, and ideally tends to infinite. These filters have been written in VHLD, and synthesized for FPGA. Two spike-based band-pass filters presented take advantages of the spike rate coded representation to perform a massively parallel processing without complex hardware units, like floating point arithmetic units, or a large memory. These low requirements of hardware allow the integration of a high number of filters inside a FPGA, allowing to process several spike coded signals fully in parallel.Ministerio de Ciencia e Innovación TEC2009-10639-C04-0

Musical notes classification with Neuromorphic Auditory System using FPGA and a Convolutional Spiking Network

In this paper, we explore the capabilities of a sound classification system that combines both a novel FPGA cochlear model implementation and a bio-inspired technique based on a trained convolutional spiking network. The neuromorphic auditory system that is used in this work produces a form of representation that is analogous to the spike outputs of the biological cochlea. The auditory system has been developed using a set of spike-based processing building blocks in the frequency domain. They form a set of band pass filters in the spike-domain that splits the audio information in 128 frequency channels, 64 for each of two audio sources. Address Event Representation (AER) is used to communicate the auditory system with the convolutional spiking network. A layer of convolutional spiking network is developed and trained on a computer with the ability to detect two kinds of sound: artificial pure tones in the presence of white noise and electronic musical notes. After the training process, the presented system is able to distinguish the different sounds in real-time, even in the presence of white noise.Ministerio de Economía y Competitividad TEC2012-37868-C04-0

On the AER Stereo-Vision Processing: A Spike Approach to Epipolar Matching

Image processing in digital computer systems usually considers visual information as a sequence of frames. These frames are from cameras that capture reality for a short period of time. They are renewed and transmitted at a rate of 25-30 fps (typical real-time scenario). Digital video processing has to process each frame in order to detect a feature on the input. In stereo vision, existing algorithms use frames from two digital cameras and process them pixel by pixel until it finds a pattern match in a section of both stereo frames. To process stereo vision information, an image matching process is essential, but it needs very high computational cost. Moreover, as more information is processed, the more time spent by the matching algorithm, the more inefficient it is. Spike-based processing is a relatively new approach that implements processing by manipulating spikes one by one at the time they are transmitted, like a human brain. The mammal nervous system is able to solve much more complex problems, such as visual recognition by manipulating neuron’s spikes. The spike-based philosophy for visual information processing based on the neuro-inspired Address-Event- Representation (AER) is achieving nowadays very high performances. The aim of this work is to study the viability of a matching mechanism in a stereo-vision system, using AER codification. This kind of mechanism has not been done before to an AER system. To do that, epipolar geometry basis applied to AER system are studied, and several tests are run, using recorded data and a computer. The results and an average error are shown (error less than 2 pixels per point); and the viability is proved

Simulating Building Blocks for Spikes Signals Processing

In this paper we will explain in depth how we have used Simulink with the addition of Xilinx System Generation to design a simulation framework for testing and analyzing neuro-inspired elements for spikes rate coded signals processing. Those elements have been designed as building blocks, which represent spikes processing primitives, combining them we have designed more complex blocks, which behaves like analog frequency filter using digital circuits. This kind of computation performs a massively parallel processing without complex hardware units. Spikes processing building blocks have been written in VHDL to be implemented for FPGA. Xilinx System Generator allows co-simulating VHDL entities together with Simulink components, providing an easy interface for presented building block simulations and analysis.Ministerio de Ciencia e Innovación TEC2009-10639-C04-0

Real-time motor rotation frequency detection with event-based visual and spike-based auditory AER sensory integration for FPGA

Multisensory integration is commonly used in various robotic areas to collect more environmental information using different and complementary types of sensors. Neuromorphic engineers mimics biological systems behavior to improve systems performance in solving engineering problems with low power consumption. This work presents a neuromorphic sensory integration scenario for measuring the rotation frequency of a motor using an AER DVS128 retina chip (Dynamic Vision Sensor) and a stereo auditory system on a FPGA completely event-based. Both of them transmit information with Address-Event-Representation (AER). This integration system uses a new AER monitor hardware interface, based on a Spartan-6 FPGA that allows two operational modes: real-time (up to 5 Mevps through USB2.0) and data logger mode (up to 20Mevps for 33.5Mev stored in onboard DDR RAM). The sensory integration allows reducing prediction error of the rotation speed of the motor since audio processing offers a concrete range of rpm, while DVS can be much more accurate.Ministerio de Economía y Competitividad TEC2012-37868-C04-02/0

Live Demonstration: Real-time motor rotation frequency detection by spike-based visual and auditory AER sensory integration for FPGA

Multisensory integration is commonly used in various robotic areas to collect much more information from an environment using different and complementary types of sensors. This demonstration presents a scenario where the motor rotation frequency is obtained using an AER DVS128 retina chip (Dynamic Vision Sensor) and a frequency decomposer auditory system on a FPGA that mimics a biological cochlea. Both of them are spike-based sensors with Address-Event-Representation (AER) outputs. A new AER monitor hardware interface, based on a Spartan-6 FPGA, allows two operational modes: real-time (up to 5 Mevps through USB2.0) and off-line mode (up to 20Mevps and 33.5Mev stored in DDR RAM). The sensory integration allows the bio-inspired cochlea limit to provide a concrete range of rpm approaches, which are obtained by the silicon retina.Ministerio de Economía y Competitividad TEC2012-37868-C04-02/0