Applying Hypervisor-Based Fault Tolerance Techniques to Safety-Critical Embedded Systems

This document details the work conducted through the development of this thesis, and it is structured as follows: • Chapter 1, Introduction, has briefly presented the motivation, objectives, and contributions of this thesis. • Chapter 2, Fundamentals, exposes a series of concepts that are necessary to correctly understand the information presented in the rest of the thesis, such as the concepts of virtualization, hypervisors, or software-based fault tolerance. In addition, this chapter includes an exhaustive review and comparison between the different hypervisors used in scientific studies dealing with safety-critical systems, and a brief review of some works that try to improve fault tolerance in the hypervisor itself, an area of research that is outside the scope of this work, but that complements the mechanism presented and could be established as a line of future work. • Chapter 3, Problem Statement and Related Work, explains the main reasons why the concept of Hypervisor-Based Fault Tolerance was born and reviews the main articles and research papers on the subject. This review includes both papers related to safety-critical embedded systems (such as the research carried out in this thesis) and papers related to cloud servers and cluster computing that, although not directly applicable to embedded systems, may raise useful concepts that make our solution more complete or allow us to establish future lines of work. • Chapter 4, Proposed Solution, begins with a brief comparison of the work presented in Chapter 3 to establish the requirements that our solution must meet in order to be as complete and innovative as possible. It then sets out the architecture of the proposed solution and explains in detail the two main elements of the solution: the Voter and the Health Monitoring partition. • Chapter 5, Prototype, explains in detail the prototyping of the proposed solution, including the choice of the hypervisor, the processing board, and the critical functionality to be redundant. With respect to the voter, it includes prototypes for both the software version (the voter is implemented in a virtual machine) and the hardware version (the voter is implemented as IP cores on the FPGA). • Chapter 6, Evaluation, includes the evaluation of the prototype developed in Chapter 5. As a preliminary step and given that there is no evidence in this regard, an exercise is carried out to measure the overhead involved in using the XtratuM hypervisor versus not using it. Subsequently, qualitative tests are carried out to check that Health Monitoring is working as expected and a fault injection campaign is carried out to check the error detection and correction rate of our solution. Finally, a comparison is made between the performance of the hardware and software versions of Voter. • Chapter 7, Conclusions and Future Work, is dedicated to collect the conclusions obtained and the contributions made during the research (in the form of articles in journals, conferences and contributions to projects and proposals in the industry). In addition, it establishes some lines of future work that could complete and extend the research carried out during this doctoral thesis.Programa de Doctorado en Ciencia y Tecnología Informática por la Universidad Carlos III de MadridPresidente: Katzalin Olcoz Herrero.- Secretario: Félix García Carballeira.- Vocal: Santiago Rodríguez de la Fuent

Aporte de la cibernética de segundo orden como estrategia pedagógica en la educación universitaria

El principal objetivo de este ensayo es revisar desde la teoría sistémica si la cibernética de segundo orden proporciona algún aporte pedagógico en la educación universitaria formativa y formadora. Teniendo en cuenta que los principales elementos de la cibernética de segundo orden son la regulación y la información, intenta abordar la educación universitaria desde estos conceptos, traducidos a enfoques pedagógicos y métodos evaluativos y didácticos que facilitan al docente su acción formadora y al estudiante la acción formativa, generando así una corresponsabilidad en el proceso de aprendizaje.The main objective of this essay is to review from the systemic theory if the second-order cybernetics provides a pedagogical contribution in the university formative and forming education. Bearing in mind that the main elements of second-order cybernetics are regulation and information, is intended to address university education from these concepts, translated into teaching approaches, assessment methods and didactical methods that will facilitate the training activity to teachers and the action trainer to students, routing them to generate a shared responsibility in learning process

Análisis de la sentencia n.º 001-10-SIN-CC. Casos n.º 0008-09-IN y 0011-09-IN sobre acción de inconstitucionalidad en contra de la Ley de Minería y efectos posteriores (Jurisprudencia)

This paper aims to analyze the decision issued by the Constitutional Court for Transition within the unconstitutionality presented against the Mining Act. Proponents, in the main, formal allege unconstitutional by the Mining Law have been issued by the Committee on Legislation and Oversight (National Assembly during the Transitional Period after the adoption of the 2008 Constitution) without the prior execution of a legislative pre query, this query being a collective right of national, indigenous peoples and communities recognized in Article 57 paragraph 17 of the Constitution of the Republic. The Constitutional Court ruled Transition to reject the unconstitutionality confirming the constitutionality of the regulatory body and the substantial and non-formal pre-legislative consultation.El presente trabajo tiene por objeto analizar la sentencia emitida por la Corte Constitucional para el Período de Transición dentro de la acción de inconstitucionalidad que se presenta en contra de la Ley de Minería. Los proponentes, en lo principal, alegan la inconstitucionalidad formal de la Ley de Minería por haber sido expedida por la Comisión de Legislación y Fiscalización (Asamblea Nacional durante el Período de Transición luego de la aprobación de la Constitución del 2008) sin la realización previa de una consulta prelegislativa, siendo esta consulta un derecho colectivo de nacionales, pueblos y comunidades indígenas reconocido en el art. 57 numeral 17 de la Constitución de la República. La Corte Constitucional para el Período de Transición resolvió rechazar la acción de inconstitucionalidad ratificando la constitucionalidad de dicho cuerpo normativo y el carácter sustancial y no formal de la consulta prelegislativa

Comparación de resultados arrojados por un modelo simplificado a partir de información de corrientes poco complejas simuladas en Qual2kw

La modelación de la calidad de agua como herramienta de planificación del recurso hídrico se hace cada vez más necesaria para minimizar los conflictos que surgen en torno al mismo, incluyendo las corrientes poco complejas afectadas por pequeños vertimientos; sin embargo, no se realiza la respectiva modelación bajo los lineamientos de la normatividad colombiana, esto ocasiona que queden en la ilegalidad. En este sentido, se presenta en este trabajo, una comparación entre un modelo complejo y un modelo simplificado aplicados al río Quinchía y a la quebrada Dosquebradas, y se constituye como alternativa viable de evaluación ambiental de vertimientos en corrientes poco intervenidas, mas no como instrumento de planificación y ordenamiento del recurso hídrico

Motivations to consume ecological foods in alternative food networks (AFNs) in southern Spain

Purpose The purpose of this paper is to identify the motivations to consume ecological foods in alternative food networks (AFNs). Design/methodology/approach In total, 150 questionnaires were applied; the questionnaire was adapted from Food Choice Questionnaire (Steptoe et al., 1995). Data were analyzed by means of multivariate statistics with factor and cluster analysis. In order to identify statistical differences (p<0.05), Kruskal–Wallis and Mann–Whitney nonparametric tests were performed. Findings Ten factors or motivations were found: social ecological concern, nutritional content, sensory aspects, certifications, naturalness, specialized consumption, trust in the seller, economic aspects, health and availability. Four groups were obtained and called: citizen consumers, in-process citizen consumers, conscious social consumers with no interest in certifications and conscious pragmatic consumers. It is concluded that differentiated consumers visit these establishments and their motivations are diverse, albeit they concur, to a varying extent, with the objectives of AFNs, finding a mixture of hedonic and ethical motivations. Practical implications This sort of works about specific places of consumption as well as specific consumers, in this case ecological, contributes to the development of future social research on other contexts, different consumers and products. Originality/value This sort of research has been carried out in various European cities, with a number of foods and over various sales channels; however, at present there is a debate around AFNs and the veracity of their goals. This way, the present work can contribute with an answer to whether the goals match the motivations of consumers

Minimax Forward and Backward Learning of Evolving Tasks with Performance Guarantees

For a sequence of classification tasks that arrive over time, it is common that tasks are evolving in the sense that consecutive tasks often have a higher similarity. The incremental learning of a growing sequence of tasks holds promise to enable accurate classification even with few samples per task by leveraging information from all the tasks in the sequence (forward and backward learning). However, existing techniques developed for continual learning and concept drift adaptation are either designed for tasks with time-independent similarities or only aim to learn the last task in the sequence. This paper presents incremental minimax risk classifiers (IMRCs) that effectively exploit forward and backward learning and account for evolving tasks. In addition, we analytically characterize the performance improvement provided by forward and backward learning in terms of the tasks' expected quadratic change and the number of tasks. The experimental evaluation shows that IMRCs can result in a significant performance improvement, especially for reduced sample sizes

Determinantes de acceso al segundo mercado para las Pymes del subsector de confección de prendas de vestir excepto prendas de piel en Bogotá

Las Pymes en Colombia concentran sus fuentes de financiamiento en el mercado intermediado o mercado bancario, desaprovechando los beneficios que brindan los instrumentos del mercado de valores a través del segundo mercado (un espacio ajustado a las necesidades de financiación de las Pymes). Por tal motivo, el presente trabajo pretende identificar los factores que determinan el acceso al segundo mercado de las Pymes del subsector de prendas de vestir excepto prendas de piel en Bogotá, a través de una metodología basada en un enfoque mixto puro, en donde tanto el método cuantitativo como cualitativo cuentan con el mismo peso y se desarrollan de manera simultánea. El enfoque cualitativo es realizado a partir de revisión documental de fuentes secundarias y la aplicación de una encuesta de opinión, mientras que el enfoque cuantitativo se desarrolla a partir de un modelo de regresión con datos panel. El hallazgo más importante del documento se centra en afirmar que el acceso a información, el desarrollo del mercado, la educación, el gobierno corporativo, la coyuntura; así como el tamaño, la rentabilidad, la tangibilidad, el endeudamiento a corto plazo, el costo de la deuda y la antigüedad, influyen para que las Pymes accedan al segundo mercad

Procesado en tiempo real de rutas e incidencias aéreas para la gestión de drones comerciales

Currently, we all know the concept of Unmanned Aerial Vehicles (UAV), although we refer to them colloquially as drones. See one of these small aircraft, which need no pilot on board, spraying a plantation, recording the traffic situation, flying over the scene of a concert or delivering a package are situations that, although recently seemed science fiction, start to assumme a strong note of reality. The advancement of technology allows these devices, historically linked to military operations, reach millions of homes and businesses around the world, helping people to perform tasks that were not possible before, or had a very high risk to be. As it has happened with other technologies at this times that we live in, what began as an eccentricity has become an advantageous option and, soon, will be an irreplaceable necessity. Drones begin to be everywhere and, of course, begin to create problems. Among its infinite virtues are some capabilities that, for misconduct or sheer recklessness, can cause serious problems in airspace or threaten physical integrity and privacy of people. Are we prepared to meet these challenges? Will we be prepared when drones that fly through the skies every day will be counted by millions? In this project these questions are addressed, posing the problem and trying to design a valid solution utilizing new Big Data analysis tools. In addition, a prototype showing a first implementation of this design it is presented and tested.Actualmente, todos conocemos el concepto de los vehículos aéreos no tripulados, aunque nos refiramos a ellos coloquialmente como drones. Ver a una de estas pequeñas aeronaves, que no necesitan de piloto a bordo, fumigando una plantación, grabando la situación del tráfico, sobrevolando el escenario de un concierto o repartiendo un paquete son situaciones que, aunque hace poco parecían de ciencia ficción, comienzan a coger claros tintes de realidad. El avance de la tecnología permite que estos aparatos, históricamente ligados a operaciones militares, lleguen a millones de hogares y empresas de todo el mundo, ayudando al ser humano a realizar tareas que antes no eran posibles, o tenían un riesgo muy elevado. Como ha ocurrido con otras tecnologías en este tiempo que nos ha tocado vivir, lo que comenzó siendo una excentricidad se ha convertido en una opción ventajosa y, dentro de poco, será una necesidad irremplazable. Los drones comienzan a estar en todas partes y, evidentemente, comienzan a crear problemas. Entre sus infinitas virtudes se encuentran algunas capacidades que, por mala intención o por pura imprudencia, pueden provocar graves accidentes en el espacio aéreo o atentar contra la integridad física y la privacidad de las personas. ¿Estamos preparados para hacer frente a estos desafíos? ¿Lo estaremos cuando se cuenten por millones los drones que surquen los cielos cada día? En este proyecto se abordan estas preguntas, planteando el problema y tratando de diseñar una solución válida que utilice las tecnologías de análisis de Big Data existentes hoy en día. Además, se presenta y se pone a prueba un prototipo que muestra una primera implementación de este diseño.Ingeniería en Tecnologías de Telecomunicació