Soporte de tiempo real en redes inalámbricas de sensores

Esta Tesis Doctoral pretende proporcionar un mecanismo que permita crear un esquema de sincronización en Redes Inalámbricas de Sensores. El mecanismo desarrollado permitirá sincronizar una red de nodos teniendo en cuenta los gradientes de temperatura existentes en el entorno de trabajo. Con esta motivación, se ha desarrollado este trabajo, el cual presenta dos aportaciones científicas principales: La primera de ellas es la creación de un modelo matemático dependiente de la temperatura, el cual permita ajustar los diferentes desfases producidos en el oscilador del sistemas como consecuencia de las variaciones de temperatura. La segunda aportación consiste en la creación de cuatro protocolos de sincronización basados en el modelo matemático previamente citado. Los citados protocolos no sólo son capaces de mejorar el comportamiento del error de sincronización frente a cambios de temperatura, sino que además, mejoran el error de sincronización con respecto al protocolo de sincronización FTSPThis Ph. Thesis aims to provide a mechanism for synchronizing Wireless Sensor Networks. It allows the synchronization of a network under changing temperature conditions minimizing the average synchronization error. This work provides two main scientific contributions: The first one is the development of a new mathematical model based on temperature changes. Using this model, the impact of the oscillator drifts in synchronization protocols is reduced. The second contribution is the proposal of four new synchronization protocols based on the above mentioned mathematical model. Compared to FTSP, these protocols reduce the average synchronization error in all situations, especially, under temperature variations. i

Homomorphic Filtering for Improving Time Synchronization in Wireless Networks

Wireless sensor networks are used to sample the environment in a distributed way. Therefore, it is mandatory for all of the measurements to be tightly synchronized in order to guarantee that every sensor is sampling the environment at the exact same instant of time. The synchronization drift gets bigger in environments suffering from temperature variations. Thus, this work is focused on improving time synchronization under deployments with temperature variations. The working hypothesis demonstrated in this work is that the clock skew of two nodes (the ratio of the real frequencies of the oscillators) is composed of a multiplicative combination of two main components: the clock skew due to the variations between the cut of the crystal of each oscillator and the clock skew due to the different temperatures affecting the nodes. By applying a nonlinear filtering, the homomorphic filtering, both components are separated in an effective way. A correction factor based on temperature, which can be applied to any synchronization protocol, is proposed. For testing it, an improvement of the FTSP synchronization protocol has been developed and physically tested under temperature variation scenarios using TelosB motes flashed with the IEEE 802.15.4 implementation supplied by TinyOS

mDARAL: A Multi-Radio Version for the DARAL Routing Algorithm

Smart Cities are called to change the daily life of human beings. This concept permits improving the efficiency of our cities in several areas such as the use of water, energy consumption, waste treatment, and mobility both for people as well as vehicles throughout the city. This represents an interconnected scenario in which thousands of embedded devices need to work in a collaborative way both for sensing and modifying the environment properly. Under this scenario, the majority of devices will use wireless protocols for communicating among them, representing a challenge for optimizing the use of the electromagnetic spectrum. When the density of deployed nodes increases, the competition for using the physical medium becomes harder and, in consequence, traffic collisions will be higher, affecting data-rates in the communication process. This work presents mDARAL, a multi-radio routing algorithm based on the Dynamic and Adaptive Radio Algorithm (DARAL), which has the capability of isolating groups of nodes into sub-networks. The nodes of each sub-network will communicate among them using a dedicated radio frequency, thus isolating the use of the radio channel to a reduced number of nodes. Each sub-network will have a master node with two physical radios, one for communicating with its neighbours and the other for being the contact point among its group and other sub-networks. The communication among sub-networks is done through master nodes in a dedicated radio frequency. The algorithm works to maximize the overall performance of the network through the distribution of the traffic messages into unoccupied frequencies. The obtained results show that mDARAL achieves great improvement in terms of the number of control messages necessary to connect a node to the network, convergence time and energy consumption during the connection phase compared to DARAL

Desarrollo de un sistema de toma de decisiones autónomo y ejemplo de aplicación a servicios de seguridad bajo demanda

Existen multitud de sistemas de adquisición de datos autónomos basados en diferentes metodologías, muchos de ellos se imparten en la educación universitaria y otros por el contrario surgen de un exhaustivo trabajo de investigación científica. Estos sistemas se aplican hoy en día en un gran número de áreas, siendo todas ellas muy diversas aunque con importantes nexos comunes. En el presente artículo se propone, a partir de un proyecto fin de carrera, un sistema autónomo de adquisición de datos y reconocimiento del entorno, con un alto índice de escalabilidad e integración a nuevos espacios. Para probar su eficacia se propone también una aplicación robotizada que utiliza estas características en el área de la seguridad, un campo en el que resultan especialmente claras las propiedades diferenciadoras del método propuesto

ZigBee Pulse Oximeter

This work presents a prototype to adapt a standard pulse oximeter by turning it into a wireless device using ZigBee. Patient’s data are extracted and transmitted to the server in real time through a Wireless Sensor Network. This Wireless Sensor Network is deployed using the mesh topology in order to reach the maximum reliability in the communications. The pulse oximeter is based on a Nellcor DS-100a probe and is controlled by an Arduino FIO with a XBee wireless modem. The amplifier circuit which is designed to extract the information of the pulse oximeter probe is included in this work

Supervisión del alumnado mediante diario de clase y herramientas web

[SPA]En el presente trabajo se expone una experiencia docente dentro de la adaptación al EEES. Lleva a cabo el uso de herramientas web para la implantación de planificaciones y diarios de clase que permiten un mejor seguimiento y supervisión de la asignatura. Finalmente se presenta un análisis, así como conclusiones y trabajos futuros. [ENG]The present work describes a teaching experience in adapting to the EEES. Concretely, carried out using web tools for implementing daily class schedules and allowing better monitoring and supervision of the subject. Finally, we present an analysis and conclusions and future work.Campus Mare Nostrum, Universidad Politécnica de Cartagena, Universidad de Murcia, Región de Murci

Experiencia docente en el desarrollo de competencias transversales como metodología de aprendizaje y evaluación

[SPA]En este trabajo se presenta una experiencia docente enfocada desde la óptica del EEES y conducente a la obtención de competencias transversales. La experiencia docente resume el desarrollo y evaluación de varias competencias transversales en el ámbito de la asignatura Interfaces y Periféricos de la Universidad de Córdoba. La metodología se centra en la construcción de una tarjeta de sonido USB y la programación del funcionamiento de ésta, sirviendo como base para desarrollar/evaluar varias competencias transversales. La evaluación de las competencias se realizará mediante una ficha que contempla distintos indicadores para cada competencia. Finalmente se analizarán los resultados y se proyectarán varias conclusiones de esta experiencia. [ENG]This paper presents an educational experience focused on the perspective of the EEES and conducive to the achievement of transversal competences. Teaching experience summarizes the development and evaluation of several transversal competences in the Interfaces and Peripherals subject, field of University of Córdoba. The methodology focuses on building a USB sound card and its programming operation, serving as a basis for developing / evaluating several transversal competences. The competence assessment will be made by a worksheet that provides different indicators for each competence. Finally we analyze the results and show some conclusions from this experience.Campus Mare Nostrum, Universidad Politécnica de Cartagena, Universidad de Murcia, Región de Murci

A Review of the Bayesian Occupancy Filter

Autonomous vehicle systems are currently the object of intense research within scientific and industrial communities; however, many problems remain to be solved. One of the most critical aspects addressed in both autonomous driving and robotics is environment perception, since it consists of the ability to understand the surroundings of the vehicle to estimate risks and make decisions on future movements. In recent years, the Bayesian Occupancy Filter (BOF) method has been developed to evaluate occupancy by tessellation of the environment. A review of the BOF and its variants is presented in this paper. Moreover, we propose a detailed taxonomy where the BOF is decomposed into five progressive layers, from the level closest to the sensor to the highest abstract level of risk assessment. In addition, we present a study of implemented use cases to provide a practical understanding on the main uses of the BOF and its taxonomy.This work has been founded by the Spanish Ministry of Economy and Competitiveness along with the European Structural and Investment Funds in the National Project TCAP-AUTO (RTC-2015-3942-4) in the program of “Retos Colaboración 2014”

Autofocus method for automated microscopy using embedded GPUs

In this paper we present a method for autofocusing images of sputum smears taken from a microscope which combines the finding of the optimal focus distance with an algorithm for extending the depth of field (EDoF). Our multifocus fusion method produces an unique image where all the relevant objects of the analyzed scene are well focused, independently to their distance to the sensor. This process is computationally expensive which makes unfeasible its automation using traditional embedded processors. For this purpose a low-cost optimized implementation is proposed using limited resources embedded GPU integrated on cutting-edge NVIDIA system on chip. The extensive tests performed on different sputum smear image sets show the real-time capabilities of our implementation maintaining the quality of the output image.This work has been partly supported by the Spanish grant CTM2014-51907