Error Detection and Diagnosis for System-on-Chip in Space Applications

Tesis por compendio de publicacionesLos componentes electrónicos comerciales, comúnmente llamados componentes Commercial-Off-The-Shelf (COTS) están presentes en multitud de dispositivos habituales en nuestro día a día. Particularmente, el uso de microprocesadores y sistemas en chip (SoC) altamente integrados ha favorecido la aparición de dispositivos electrónicos cada vez más inteligentes que sostienen el estilo de vida y el avance de la sociedad moderna. Su uso se ha generalizado incluso en aquellos sistemas que se consideran críticos para la seguridad, como vehículos, aviones, armamento, dispositivos médicos, implantes o centrales eléctricas. En cualquiera de ellos, un fallo podría tener graves consecuencias humanas o económicas. Sin embargo, todos los sistemas electrónicos conviven constantemente con factores internos y externos que pueden provocar fallos en su funcionamiento. La capacidad de un sistema para funcionar correctamente en presencia de fallos se denomina tolerancia a fallos, y es un requisito en el diseño y operación de sistemas críticos. Los vehículos espaciales como satélites o naves espaciales también hacen uso de microprocesadores para operar de forma autónoma o semi autónoma durante su vida útil, con la dificultad añadida de que no pueden ser reparados en órbita, por lo que se consideran sistemas críticos. Además, las duras condiciones existentes en el espacio, y en particular los efectos de la radiación, suponen un gran desafío para el correcto funcionamiento de los dispositivos electrónicos. Concretamente, los fallos transitorios provocados por radiación (conocidos como soft errors) tienen el potencial de ser una de las mayores amenazas para la fiabilidad de un sistema en el espacio. Las misiones espaciales de gran envergadura, típicamente financiadas públicamente como en el caso de la NASA o la Agencia Espacial Europea (ESA), han tenido históricamente como requisito evitar el riesgo a toda costa por encima de cualquier restricción de coste o plazo. Por ello, la selección de componentes resistentes a la radiación (rad-hard) específicamente diseñados para su uso en el espacio ha sido la metodología imperante en el paradigma que hoy podemos denominar industria espacial tradicional, u Old Space. Sin embargo, los componentes rad-hard tienen habitualmente un coste mucho más alto y unas prestaciones mucho menores que otros componentes COTS equivalentes. De hecho, los componentes COTS ya han sido utilizados satisfactoriamente en misiones de la NASA o la ESA cuando las prestaciones requeridas por la misión no podían ser cubiertas por ningún componente rad-hard existente. En los últimos años, el acceso al espacio se está facilitando debido en gran parte a la entrada de empresas privadas en la industria espacial. Estas empresas no siempre buscan evitar el riesgo a toda costa, sino que deben perseguir una rentabilidad económica, por lo que hacen un balance entre riesgo, coste y plazo mediante gestión del riesgo en un paradigma denominado Nuevo Espacio o New Space. Estas empresas a menudo están interesadas en entregar servicios basados en el espacio con las máximas prestaciones y el mayor beneficio posibles, para lo cual los componentes rad-hard son menos atractivos debido a su mayor coste y menores prestaciones que los componentes COTS existentes. Sin embargo, los componentes COTS no han sido específicamente diseñados para su uso en el espacio y típicamente no incluyen técnicas específicas para evitar que los efectos de la radiación afecten su funcionamiento. Los componentes COTS se comercializan tal cual son, y habitualmente no es posible modificarlos para mejorar su resistencia a la radiación. Además, los elevados niveles de integración de los sistemas en chip (SoC) complejos de altas prestaciones dificultan su observación y la aplicación de técnicas de tolerancia a fallos. Este problema es especialmente relevante en el caso de los microprocesadores. Por tanto, existe un gran interés en el desarrollo de técnicas que permitan conocer y mejorar el comportamiento de los microprocesadores COTS bajo radiación sin modificar su arquitectura y sin interferir en su funcionamiento para facilitar su uso en el espacio y con ello maximizar las prestaciones de las misiones espaciales presentes y futuras. En esta Tesis se han desarrollado técnicas novedosas para detectar, diagnosticar y mitigar los errores producidos por radiación en microprocesadores y sistemas en chip (SoC) comerciales, utilizando la interfaz de traza como punto de observación. La interfaz de traza es un recurso habitual en los microprocesadores modernos, principalmente enfocado a soportar las tareas de desarrollo y depuración del software durante la fase de diseño. Sin embargo, una vez el desarrollo ha concluido, la interfaz de traza típicamente no se utiliza durante la fase operativa del sistema, por lo que puede ser reutilizada sin coste. La interfaz de traza constituye un punto de conexión viable para observar el comportamiento de un microprocesador de forma no intrusiva y sin interferir en su funcionamiento. Como resultado de esta Tesis se ha desarrollado un módulo IP capaz de recabar y decodificar la información de traza de un microprocesador COTS moderno de altas prestaciones. El IP es altamente configurable y personalizable para adaptarse a diferentes aplicaciones y tipos de procesadores. Ha sido diseñado y validado utilizando el dispositivo Zynq-7000 de Xilinx como plataforma de desarrollo, que constituye un dispositivo COTS de interés en la industria espacial. Este dispositivo incluye un procesador ARM Cortex-A9 de doble núcleo, que es representativo del conjunto de microprocesadores hard-core modernos de altas prestaciones. El IP resultante es compatible con la tecnología ARM CoreSight, que proporciona acceso a información de traza en los microprocesadores ARM. El IP incorpora técnicas para detectar errores en el flujo de ejecución y en los datos de la aplicación ejecutada utilizando la información de traza, en tiempo real y con muy baja latencia. El IP se ha validado en campañas de inyección de fallos y también en radiación con protones y neutrones en instalaciones especializadas. También se ha combinado con otras técnicas de tolerancia a fallos para construir técnicas híbridas de mitigación de errores. Los resultados experimentales obtenidos demuestran su alta capacidad de detección y potencialidad en el diagnóstico de errores producidos por radiación. El resultado de esta Tesis, desarrollada en el marco de un Doctorado Industrial entre la Universidad Carlos III de Madrid (UC3M) y la empresa Arquimea, se ha transferido satisfactoriamente al entorno empresarial en forma de un proyecto financiado por la Agencia Espacial Europea para continuar su desarrollo y posterior explotación.Commercial electronic components, also known as Commercial-Off-The-Shelf (COTS), are present in a wide variety of devices commonly used in our daily life. Particularly, the use of microprocessors and highly integrated System-on-Chip (SoC) devices has fostered the advent of increasingly intelligent electronic devices which sustain the lifestyles and the progress of modern society. Microprocessors are present even in safety-critical systems, such as vehicles, planes, weapons, medical devices, implants, or power plants. In any of these cases, a fault could involve severe human or economic consequences. However, every electronic system deals continuously with internal and external factors that could provoke faults in its operation. The capacity of a system to operate correctly in presence of faults is known as fault-tolerance, and it becomes a requirement in the design and operation of critical systems. Space vehicles such as satellites or spacecraft also incorporate microprocessors to operate autonomously or semi-autonomously during their service life, with the additional difficulty that they cannot be repaired once in-orbit, so they are considered critical systems. In addition, the harsh conditions in space, and specifically radiation effects, involve a big challenge for the correct operation of electronic devices. In particular, radiation-induced soft errors have the potential to become one of the major risks for the reliability of systems in space. Large space missions, typically publicly funded as in the case of NASA or European Space Agency (ESA), have followed historically the requirement to avoid the risk at any expense, regardless of any cost or schedule restriction. Because of that, the selection of radiation-resistant components (known as rad-hard) specifically designed to be used in space has been the dominant methodology in the paradigm of traditional space industry, also known as “Old Space”. However, rad-hard components have commonly a much higher associated cost and much lower performance that other equivalent COTS devices. In fact, COTS components have already been used successfully by NASA and ESA in missions that requested such high performance that could not be satisfied by any available rad-hard component. In the recent years, the access to space is being facilitated in part due to the irruption of private companies in the space industry. Such companies do not always seek to avoid the risk at any cost, but they must pursue profitability, so they perform a trade-off between risk, cost, and schedule through risk management in a paradigm known as “New Space”. Private companies are often interested in deliver space-based services with the maximum performance and maximum benefit as possible. With such objective, rad-hard components are less attractive than COTS due to their higher cost and lower performance. However, COTS components have not been specifically designed to be used in space and typically they do not include specific techniques to avoid or mitigate the radiation effects in their operation. COTS components are commercialized “as is”, so it is not possible to modify them to improve their susceptibility to radiation effects. Moreover, the high levels of integration of complex, high-performance SoC devices hinder their observability and the application of fault-tolerance techniques. This problem is especially relevant in the case of microprocessors. Thus, there is a growing interest in the development of techniques allowing to understand and improve the behavior of COTS microprocessors under radiation without modifying their architecture and without interfering with their operation. Such techniques may facilitate the use of COTS components in space and maximize the performance of present and future space missions. In this Thesis, novel techniques have been developed to detect, diagnose, and mitigate radiation-induced errors in COTS microprocessors and SoCs using the trace interface as an observation point. The trace interface is a resource commonly found in modern microprocessors, mainly intended to support software development and debugging activities during the design phase. However, it is commonly left unused during the operational phase of the system, so it can be reused with no cost. The trace interface constitutes a feasible connection point to observe microprocessor behavior in a non-intrusive manner and without disturbing processor operation. As a result of this Thesis, an IP module has been developed capable to gather and decode the trace information of a modern, high-end, COTS microprocessor. The IP is highly configurable and customizable to support different applications and processor types. The IP has been designed and validated using the Xilinx Zynq-7000 device as a development platform, which is an interesting COTS device for the space industry. This device features a dual-core ARM Cortex-A9 processor, which is a good representative of modern, high-end, hard-core microprocessors. The resulting IP is compatible with the ARM CoreSight technology, which enables access to trace information in ARM microprocessors. The IP is able to detect errors in the execution flow of the microprocessor and in the application data using trace information, in real time and with very low latency. The IP has been validated in fault injection campaigns and also under proton and neutron irradiation campaigns in specialized facilities. It has also been combined with other fault-tolerance techniques to build hybrid error mitigation approaches. Experimental results demonstrate its high detection capabilities and high potential for the diagnosis of radiation-induced errors. The result of this Thesis, developed in the framework of an Industrial Ph.D. between the University Carlos III of Madrid (UC3M) and the company Arquimea, has been successfully transferred to the company business as a project sponsored by European Space Agency to continue its development and subsequent commercialization.Programa de Doctorado en Ingeniería Eléctrica, Electrónica y Automática por la Universidad Carlos III de MadridPresidenta: María Luisa López Vallejo.- Secretario: Enrique San Millán Heredia.- Vocal: Luigi Di Lill

Adjusting the Labor Supply to Mitigate Violent Shocks: Evidence from Rural Colombia

This paper studies the use of labor markets to mitigate the impact of violent shocks on households in rural areas in Colombia. It examines changes in the labor supply from on-farm to off-farm labor as a means of coping with the violent shock and the ensuing redistribution of time within households. It identifies the heterogeneous response by gender. Because the incidence of violent shocks is not exogenous, the analysis uses instrumental variables that capture several dimensions of the cost of exercising terror. As a response to the violent shocks, households decrease the time spent on on-farm work and increase their supply of labor to off-farm activities (non-agricultural ones). Men carry the bulk of the adjustment in the use of time inasmuch as they supply the most hours to off-farm non-agricultural work and formal labor markets. Labor markets do not fully absorb the additional labor supply. Women in particular are unable to find jobs in formal labor markets and men have increased time dedicated to leisure and household chores. Additional off-farm supply does not fully cover the decrease in consumption. The results suggest that in rural Colombia, labor markets are a limited alternative for coping with violent shocks. Thus, policies in conflict-affected countries should go beyond short-term relief and aim at preventing labor markets from collapsing and at supporting the recovery of agricultural production.Conflict, labor markets, developing economies, instrumental variables

Diseño de un módulo observador para un microprocesador ARM9 en un SOPC

En este Trabajo de Fin de Grado se aborda el diseño de un módulo hardware capaz de observar el flujo de ejecución de un microprocesador ARM Cortex-A9, con el que poder detectar errores en su funcionamiento. Para ello ha sido necesario un profundo estudio y comprensión del subsistema ARM CoreSight donde se integra la interfaz de traza utilizada en la observación, así como su posterior configuración y pruebas de funcionamiento. La necesidad de este desarrollo se enmarca en el creciente problema que suponen los errores transitorios (en inglés soft errors) para el funcionamiento de los circuitos digitales. Es un problema tan antiguo como la electrónica, ya que tiene su principal causa en las interferencias producidas por radiación cósmica y electromagnética, y existen técnicas (denominadas “hardening” o endurecimiento) para aumentar su tolerancia a fallos desde la época de la carrera espacial. De un tiempo a esta parte, los grandes avances realizados en las tecnologías de silicio han propiciado notables incrementos tanto en sus prestaciones como en la eficiencia energética asociada, ampliando los sectores de aplicación de los microprocesadores. Sin embargo, la gran complejidad y densidad de integración asociadas, hace a las nuevas generaciones de microprocesadores cada vez más vulnerables a estos errores ya no solamente a nivel aeroespacial, sino también en aplicaciones terrestres. En cualquier sistema electrónico la fiabilidad es fundamental, y más si se utiliza en una aplicación crítica para la seguridad. Aparece, por tanto, la necesidad de renovar las técnicas de endurecimiento y adaptarlas a las nuevas necesidades, distinguiéndose tres categorías: técnicas hardware, software e híbridas. De ellas, las más efectivas son las técnicas hardware, sin embargo requieren un exhaustivo conocimiento del circuito a robustecer, información que no siempre se encuentra disponible en el ámbito del mercado de la electrónica de consumo; en el que ARM tiene una posición dominante.In this Bachelor Thesis, the design of a hardware module capable of observe the execution of an ARM Cortex-A9 is addressed, with the aim of detecting operation errors. A deep study and comprehension of ARM CoreSight subsystem has been needed, that integrates the trace interface used in observations. Also, operation tests and configurations have been done. This work is related with the rising problem involving soft errors in the digital circuits’ normal behavior. This problem is as old as electronics, and has its main cause in cosmic and electromagnetic radiation interferences. Hardening techniques have been developed in order to increase the associated fault-tolerance since the space race. In the past few years, great advances made in silicon technologies have promoted big growth both in performance as in energy efficiency. Thus, application sectors for microprocessors have been expanded. However, the big complexity and integration density reached make new processor’s generations even more vulnerable to soft errors, not only in space but also at ground level. Reliability is a must in every electronic system, more if it’s used for safety-critical applications. Therefore, the need to renew or adapt hardening techniques to new needs, appear. Three different categories can be applied: hardware techniques, software and hybrid ones. Among them, the most effective ones are hardware ones, but they require a deep knowledge about the hardened circuit. This information is not always available in consumer electronics market, in which ARM has a privileged position.Ingeniería Electrónica Industrial y Automátic

SVITE: A Spike-Based VITE Neuro-Inspired Robot Controller

This paper presents an implementation of a neuro-inspired algorithm called VITE (Vector Integration To End Point) in FPGA in the spikes domain. VITE aims to generate a non-planned trajectory for reaching tasks in robots. The algorithm has been adapted to work completely in the spike domain under Simulink simulations. The FPGA implementation consists in 4 VITE in parallel for controlling a 4-degree-of-freedom stereo-vision robot. This work represents the main layer of a complex spike-based architecture for robot neuro-inspired reaching tasks in FPGAs. It has been implemented in two Xilinx FPGA families: Virtex-5 and Spartan-6. Resources consumption comparative between both devices is presented. Results obtained for Spartan device could allow controlling complex robotic structures with up to 96 degrees of freedom per FPGA, providing, in parallel, high speed connectivity with other neuromorphic systems sending movement references. An exponential and gamma distribution test over the inter spike interval has been performed to proof the approach to the neural code proposed.Ministerio de Economía y Competitividad TEC2012-37868-C04-0

EFFECTS OF LOUVERS SHADING DEVICES ON VISUAL COMFORT AND ENERGY DEMAND OF AN OFFICE BUILDING. A CASE OF STUDY

This paper evaluates the building energy demand and visual comfort of a real case with a glazed façade office building placed in Málaga (Mediterranean city in the south of Spain). South oriented facades receive such a high solar gain that cooling demand cannot be handled by the current HVAC system. As an environmental friendly solution, a shading control strategy based on vertical and horizontal louvers is proposed. The study consists of a comparison between the actual and the refurbished building with shading devices. Daylighting simulation is done with Daysim (Daysim, 2016). A group of offices with south, east and north oriented facades is chosen for the study. Horizontal louvers in the south façade and vertical louvers in the east facade are modelled and simulated. The simulation changes the angle of the louver: 0º (perpendicular to the glazing), -30º, 30º, -60º, 60º. Visual comfort parameters analyzed are: illuminance, daylight autonomy (DA) and useful daylight index (UDI). With respect to the thermal comfort, not only louvers orientation try to provide solar protection for glazed areas in cooling period but also maximize solar gains in heating period. However, an excessive daylight could affect discomfort glare. Shading control strategy must provide the equilibrium between both aspects. Thermal demand is calculated with Trnsys (TRNSYS, 2016).Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Gaussian Markov Random fields and totally positive matrices

The present paper focuses on the study of the conditions under which the covariance matrix of a multivariate Gaussian distribution is totally positive, paying particular attention to multivariate Gaussian distributions that are Gaussian Markov Random Fields. More specifically, it is proven that, if the graph over which the Gaussian Markov Random Field is defined consists of path graphs and the covariances between adjacent variables on the graph are non-negative, then there always exists a reordering of the variables that renders the resulting covariance matrix totally positive. Moreover, this reordering is identified and some cases for which the conditions for the covariance matrix of a multivariate Gaussian distribution to be totally positive are necessary and sufficient are provided

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

Development of amino-functionalized membranes for removal of microorganism

[EN] Treatments to ensure water supply of an acceptable hygienic-sanitary quality is of vast importance. Among unconventional treatments, membrane technologies have recently stood out. Immobilization of antimicrobial compounds onto membranes can prevent fouling and lead to self-cleaning matrices. In this study, cellulose membranes functionalized with amines were developed to assess their capability to remove microbial contamination. Water samples with several levels of Escherichia coli inoculum were filtered through membranes, and different trials were run to check the system's effectiveness. The amino-functionalized membranes were able to filter water samples in a few seconds, and partially or completely remove the inoculated microorganism depending on the inoculum level. The amine-functionalized membranes displayed significant retention capacity in samples with high bacterial concentrations and were able to decontaminate water with low microbial load. Membranes can be reused with no apparent loss of efficiency. Hence, this study demonstrates the high potential of amine-functionalized membranes in drinking water treatments.Authors gratefully acknowledge the financial support from the Ministerio de Economia y Competitividad and FEDER-EU (Project AGL2015-70235-C2-1-R). N.P.G. is grateful to Generalitat Valencia for her grant. The authors also thank the Electron Microscopy Service at the UPV for support.Peña-Gomez, N.; Ruiz Rico, M.; Fernández Segovia, I.; Barat Baviera, JM. (2018). Development of amino-functionalized membranes for removal of microorganism. Innovative Food Science & Emerging Technologies. 48:75-82. https://doi.org/10.1016/j.ifset.2018.05.023S75824

Energyplus simulation model of a zoning regulation system intgegrated with an unitary ducted air-to-air heat pump

En los edificios se pueden distinguir una variedad de zonas con diferentes patrones de utilización y perfiles de cargas térmicas. Los sistemas de climatización zonificados permiten adaptarse a las diferentes demandas térmicas de cada espacio y no climatizar aquellos que no estén siendo utilizados. Recientemente, con el aumento de la disponibilidad de velocidades de ventilador de los principales fabricantes de unidades de expansión directa de pequeña y mediana potencia para conductos, se han desarrollado sistemas que se basan en lo que se denomina una “pasarela de comunicación”, que permite una mayor integración del sistema de zonas con el equipo de climatización, controlando aspectos tales como el encendido y apagado, modo de funcionamiento, velocidad del ventilador, temperatura de consigna del equipo, etc. Este trabajo presenta el desarrollo de un nuevo modelo computacional que integra estos sistemas en el programa de simulación energética EnergyPlusUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tec