ALO: Sistemas de localización y orientación por ángulos basados en recepción diferencial

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Escuela Politécnica Superior. Fecha de lectura : 20-07-2016La presente tesis doctoral presenta un algoritmo diseñado para proporcionar la localización y orientación a un nodo, necesitando para ello la existencia de una serie de balizas cuyas posiciones deben ser conocidas. El algoritmo propuesto se ha implementado utilizando señales de ultrasonidos como medio de comunicación entre balizas y nodos, obteniendo un sistema en el que los nodos son capaces de localizarse y orientarse en el interior de viviendas o naves de forma precisa (el sistema alcanza precisiones de unos pocos centímetros en la localización y de unos pocos grados en la orientación) acarreando un reducido coste adicional para cada nodo. El algoritmo se basa en que cada uno de los nodos mide el retardo con el que se recibe la señal generada por cada baliza mediante el uso de varios receptores desplegados en el propio nodo. Posteriormente, el nodo utiliza esta información para determina el ángulo con el que se recibe la señal y, combinando los ángulos percibidos por el nodo respecto a varias balizas, determinar su posición y orientación en todo momento. El algoritmo demanda un reducido coste computacional, lo que permite implementarlo en los microcontroladores o FPGAs de que ya disponen los nodos para realizar las tareas de navegación y sensado, por lo que no se incurre en un coste adicional en este sentido. Además, como el algoritmo se ejecuta en cada uno de los nodos de forma autónoma, el sistema resultante es altamente escalable, permitiendo desplegar cualquier número de nodos en un determinado espacio. En esta tesis se presentan cuatro variantes del algoritmo, las cuales se analizan en detalle tanto analítica como experimentalmente. Cada una de estas variantes permite elegir entre diferentes prestaciones, permitiendo el desarrollo de sistemas en donde cada nodo sólo necesita de un receptor, pero demanda recibir la señal de al menos 4 balizas para poder conocer su posición, hasta dispositivos con cuatro receptores que sólo necesitan de 2 balizas para conocer su posición y orientación y, además, pueden funcionar incluso con la pérdida de uno de sus receptores (a costa de una menor precisión). La decisión entre una u otra variante del algoritmo depende de las necesidades del sistema, siendo posible combinarlas. Adicionalmente, en la presente tesis se recogen los resultados obtenidos al cambiar la tecnología de ultrasonidos por una basada en sonido en el rango audible por el ser humano. Se demuestra que dicha tecnología no es adecuada al obtener mucha menor precisión debido, principalmente, al uso de una menor frecuencia en la señal de referencia y a la interferencia generada por los rebotes en las paredes, techo y objetos situados en el entorno de aplicación.This doctoral thesis presents an algorithm designed to provide the localization and orientation information to a node, requesting the deployment of multiple beacons whose positions shall be known. The performance of the algorithm has been tested using ultrasounds as the reference signals between the beacons and the nodes, obtaining a system where the nodes can locate and orientate themselves precisely in an indoor environment (with an error of a few centimeters in their position and an error of a few degrees in their orientation), demanding a low cost increase to each node. This algorithm is based on measuring the propagation delay of the signal generated at the beacons in multiple receivers deployed in each node. With this information, the node is able to know the reception angle of the signal and, combining the angles received with respect to different beacons, determines its position and orientation. The computational cost of the algorithm is so low that it can be implemented in the microcontrollers or FPGAs already used in the node for the navigation and sensing tasks, so it does not incur in any additional cost for computational purposes. Additionally, as the algorithm is executed autonomously in each node, the system supports any number of nodes deployed in a defined region, resulting in a high scalable system. Four versions of the algorithm are presented, analyzed and experimentally tested. These alternatives allow choosing a different algorithm in function on the performance demanded by the system: from systems where the node only needs one receiver, but demands staying in an area covered by four beacons to know the position of the node, up to systems where the node demands four receivers, but only needs two beacon signals to know its position and orientation. These alternatives can be combined, increasing the performance of the system. Additionally, this document shows the results obtained when the algorithm is implemented with sound signals, concluding that this technology is not a good choice as it obtains lower performance than the same algorithm implemented with ultrasonic technology. This lower performance is caused due to the lower frequency of sound signals and due to the interferences of the rebounds on the ceiling, walls and objects deployed in the environment

HALO4: Horizontal Angle Localization and Orientation System with 4 Receivers and Based on Ultrasounds

The final publication is available at Springer via http://dx.doi.org/10.1007/s10846-015-0283-2This paper presents a low cost ultrasonic localization and orientation system based on the DTOA (Differential Time Of Arrival) technique. The proposed system consists in deploying any number of autonomous nodes at the floor of a room and place some transmitters at the ceiling. Each node shall have four ultrasonic receivers to obtain the basic measures for the localization and orientation systems, and the coverage area of the system is defined by any region covered by at least three transmitters. The localization system is based on an estimation process of the horizontal angle of the node with respect to the transmitters. This implementation allows deploying the transmitters at different heights and ignores the error introduced by an incorrect estimation of the ultrasonic signal speed. The computational effort of the proposed system is greater than other ALO (Angle Localization and Orientation) systems, needing a minimization process to obtain the localization results, but it is smaller than in other typical techniques, like those based on the intersection of hyperboloids.This work has been supported by the Spanish Ministerio de Ciencia e Innovación under project TEC2009-09871

ALO: An ultrasound system for localization and orientation based on angles

This is the author’s version of a work that was accepted for publication in Microelectronics Journal. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Microelectronics Journal, Vol 44, Issue 10, (October 2013). http://dx.doi.org/10.1016/j.mejo.2013.01.001This paper presents a low cost system based on ultrasound transducers to obtain the localization and orientation information of a mobile node, such as a robot, in a 2D indoor space. The system applies a new differential time of arrival (DTOA) technique with reduced computational cost, which is called ALO (angle localization and orientation). Instead of directly calculating its position, the system calculates the direction of arrival of the received ultrasonic signal and, through it, its position and orientation. A prototype of a robot has been built in order to show the validity of the method through experimental results

ALO4: Angle localization and orientation system with four receivers

This paper presents a 2D indoor localization and orientation system based on a TDOA (Time Difference of Arrival) technique. It uses an array of receivers (four low-cost ultrasonic resonant devices in a square distribution) to implement low-computational-effort DOA (Direction of Arrival) algorithms, based on assumed plane-wave reception. The system only demands two transmitters at well-known positions on the ceiling of the room for obtaining the node position and orientation when it is deployed on the floor of the room. This system has been tested using a Xilinx Spartan-3A FPGA that implements a 52 MHz MicroBlaze. The experimental results include a total of 1,440 points, obtaining a mean localization error of 5.17 cm and a mean orientation error of 3.34 degrees. For this system, the localization and orientation processes are executed in less than 50 us.This work has been supported by the Spanish Ministerio de Ciencia e Innovacion under project TEC2009-0987

Autonomous indoor ultrasonic positioning system based on a low-cost conditioning circuit

This is the author’s version of a work that was accepted for publication in Measurement. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Measurement, Vol. 45, Issue 3, (2012) DOI: http://dx.doi.org/10.1016/j.measurement.2011.12.002This work presents a low cost 3-D location system based on ultrasonics and implemented with low-cost FPGAs. The mobile nodes of the system use distance estimation to several anchor points in order to trilaterate their positions with an accuracy of few centimeters. The ultrasonic transducers are handled with an ad hoc conditioning circuit based on instrumental amplifiers which provides high amplification keeping low noise. The proposed system is autonomous so there is no need of an external PC or other devices. A prototype of the system has been attached to a mobile robot to check the viability of the location system in a real scenario.This work has been partially supported by the TEC2009-09871 project of the Ministerio de Ciencia e Innovacion, Spain

Low cost indoor ultrasonic positioning implemented in FPGA

Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. A. Sánchez, S. Elvira, Á. de Castro, G. Gonzalez-de-Rivera, R. Ribalda, J. Garrido, "Low cost indoor ultrasonic positioning implemented in FPGA", 35th Annual Conference of IEEEIndustrial Electronics, 2009. IECON '09, Porto (Portugal), 2009, pp. 2709 - 2714This paper presents a low cost indoor ultrasonic-based positioning system. This system allows the mobile nodes of a Wireless Sensor Network to know their location using radiofrequency and ultrasonics. To achieve this goal, a matrix of transmitting anchor points is installed whereas the mobile nodes receive these transmitted signals and estimate the time-of-flight of the ultrasonic signals. Using two time-of-flight measurements and trilateration equations, the location of the mobile nodes can be inferred in a 2-D space.This work has been partially supported by the CCG08-UAM/TIC-4258 project of the Comunidad de Madrid and UAM

Sexually transmitted pathogens, coinfections and risk factors in patients attending obstetrics and gynecology clinics in Jalisco, Mexico

Objetivo. Determinar la frecuencia de nueve patógenos de transmisión sexual, coinfecciones y factores de riesgo en pacientes que acudieron a una consulta de ginecología y obstetricia en Jalisco, México. Material y métodos. Se analizaron muestras de 662 pacientes que asistieron a la consulta de ginecología y obstetricia. Se detectaron Treponema pallidum, VIH y VHC mediante serología. Se detectó VPH por Reacción de Cadena de Polimerasa (PCR) y sus genotipos se detectaron por Polimorfismos de Longitud de Fragmentos de Restricción (RFLP). Se detectaron Trichomonas vaginalis, VHS-1, VHS-2, Mycoplasma genitalium, Neisseria gonorrhoeae y T. pallidum por PCR múltiple. Resultados. Por serología, la frecuencia de VIH fue 6.8%, de T. pallidum fue 2.26% y de VHC fue 0.15%. Por PCR, la frecuencia más alta fue de VPH (13.9%, el genotipo más frecuente fue el 16, 33.7%), seguida de T. vaginalis (14.2%), VHS-1 (8.5%), M. genitalium (2.41%), N. gonorrhoeae (2.11%), VHS-2 (1.8%) y T. pallidum (1.05%). Los pacientes infectados con T. vaginalis presentaron más probabilidades de tener múltiples coinfecciones (p = 0.01). Conclusiones. La frecuencia de infección por VPH, VHS-1, VHS-2, M. genitalium y T. vaginalis fue menor a lo reportado. Sin embargo, se detectó una alta frecuencia de VIH, T. pallidum, y N. gonorrhoeae. ABSTRACT Objective. To determine the frequency of nine sexually transmitted pathogens, coinfections and risk factors in patients attending obstetrics and gynecology clinics in Jalisco, Mexico. Materials and methods. Samples from 662 patients attending obstetrics and gynecology clinics were analyzed. Treponema pallidum, HIV, and HCV were detected by serology. HPV was detected by Polimerase Chain Reac- tion (PCR), and its genotype was determined by Restriction Fragment Length Polymorphism (RFLP). Trichomonas vaginalis, HSV-1, HSV-2, Mycoplasma genitalium, Neisseria gonorrhoeae and T. pallidum were detected by multiplex PCR. Results. By serology, HIV frequency was 6.8%, T. pallidum was 2.26%, and HCV was 0.15%. By PCR, HPV frequency was 13.9%, (more frequent genotype was 16, 33.7%), followed by T. vaginalis (14.2%), HSV-1 (8.5%), M. genitalium (2,41%), N. gonorrhoeae (2.11%), HSV-2 (1.8%), and T. pallidum (1.05%). Patients infected with T. vaginalis were more likely to have multiple coinfections (p = 0.01). Conclusion. The frequency of HPV, HVS-1, HSV-2, M. genitalium and T. vaginalis was lower than that reported. However, a high frequency of HIV, T. pallidum, and N. gonorrhoeae was detected

Saúde ambiental de parques espanhóis: Abordagem ao potencial alergénico dos espaços verdes urbanos

Urban parks are green infrastructure elements that should contribute to improving the quality of life and well-being of citizens. In this work there are presented the results of applying a new index to estimate the potential allergenicity of parks located in 20 Spanish cities. This index, which considers intrinsic biological and biometric parameters of existing plant species in parks, allows the allergenic risk thereof to be calculated on a scale ranging from 0 to 1, depending on whether to the park’s allergenicity is zero or has a high risk for the population. The parks selected for this study have different typologies, sizes, species richness and biodiversities, which has yielded highly variable index values. Almost half of the analysed parks have an index value higher than 0.30, a threshold considered having a moderate to high risk, and therefore, enough to cause allergy symptoms in the population. Conversely, most of the parks had an index value below this threshold, so that the risk of suffering allergies is low or very low. The formula also allows the species that most contribute to the resulting value for allergenicity to be known, which are those having an anemophilous strategy of pollination, extended periods of flowering, and a referenced high allergenicity. These requirements are met by all species of the Betulaceae, Cupressaceae and Moraceae families, and to a lesser extent by Oleaceae and Platanaceae. It can be concluded that the development of an index to estimate the allergenicity of urban green spaces constitutes a useful tool to minimize the impact of pollen allergy on the population.Los parques urbanos son elementos de la infraestructura verde que deben contribuir a mejorar la calidad de vida y el bienestar ciudadano. En este trabajo se presentan los resultados de la aplicación de un novedoso índice que estima la alergenicidad potencial de las zonas verdes urbanas. Este índice, que contempla parámetros biológicos y biométricos intrínsecos a las especies arbóreas existentes en los parques, genera un resultado cuyo valor está comprendido entre 0 y 1 según el potencial alergénico del parque sea nulo o de riesgo alto para la población. En una primera fase el índice se ha aplicado a parques de diferente tipología, diseño, tamaño, riqueza específica y biodiversidad ubicados en 20 ciudades españolas. Los resultados han mostrado que algunos de los parques estudiados registran un valor de índice superior a 0.30, umbral suficiente para causar síntomas de alergia a la población expuesta, y por tanto, de riesgo moderado o alto. Por el contrario, en la mayoría de los parques se obtuvo un valor inferior a este umbral. También es posible conocer cuáles son las especies que más contribuyen al valor resultante, que son aquellas con estrategia de polinización anemófila, periodos de oración extensos y alta alergenicidad referenciada. Estos requisitos los cumplen todas las especies de las familias Betuláceas, Cupresáceas y Moráceas, y en menor extensión, Oleáceas y Platanáceas. Puede concluirse que el desarrollo de un índice de estimación de alergenicidad de espacios verdes urbanos constituye una herramienta de utilidad para minimizar el impacto de la alergia polínica en la población.Os parques urbanos são elementos da infraestrutura verde que devem contribuir para a melhoria da qualidade de vida dos cidadãos. Neste trabalho apresentam-se os resultados da aplicação de um índice inovador, que permite estimar a alergenicidade potencial dos espaços verdes urbanos. Este índice, que inclui parâmetros biológicos e biométricos, intrínsecos às próprias espécies existentes nos parques, tem como resultado um valor numa escala entre 0 e 1, de acordo com o potencial alergénico do parque, caso este seja, respetivamente e nos seus extremos, nulo ou de máximo risco para as populações. O índice foi aplicado em parques de diferentes tipologias, desenho, tamanho, riqueza específica e biodiversidade, situados em 20 cidades espanholas. Os resultados demonstram que alguns dos parques estudados registam um valor de índice superior a 0.30, limite su ciente para causar sintomas de alergia na população exposta, e por tanto, risco moderado a alto. No entanto, a maioria dos parques apresenta um valor inferior a este limite. Também é possível conhecer quais as espécies que mais contribuem para o valor do índice, que correspondem aquelas com a estratégia de polinização anemófila, períodos de oração extensos e potencial alergénico referenciado. Estes requisitos são aplicáveis a todas as espécies das famílias Betuláceas, Cupressáceas e Moráceas, e em menor medida, Oleáceas e Platanáceas. Pode assim concluir-se que a aplicação de um índice de previsão dos níveis de alergenicidade dos espaços verdes urbanos constitui uma ferramenta útil para minimizar o impacto da alergia polínica sobre a população