E-MIS validity applied to TELMA enhanced learning environment

Enhanced learning environments are arising with great success within the field of cognitive skills training in minimally invasive surgery (MIS) because they provides multiple benefits since they avoid time, spatial and cost constraints. TELMA [1,2] is a new technology enhanced learning platform that promotes collaborative and ubiquitous training of surgeons. This platform is based on four main modules: an authoring tool, a learning content and knowledge management system, an evaluation module and a professional network. TELMA has been designed and developed focused on the user; therefore it is necessary to carry out a user validation as final stage of the development. For this purpose, e-MIS validity [3] has been defined. This validation includes usability, contents and functionality validities both for the development and production stages of any e-Learning web platform. Using e-MIS validity, the e-Learning is fully validated since it includes subjective and objective metrics. The purpose of this study is to specify and apply a set of objective and subjective metrics using e-MIS validity to test usability, contents and functionality of TELMA environment within the development stage.

Semantic Interoperability: Perspectives and Technology Evaluation

Interoperability between semantic technologies is a must because they need to be in communication to interchange ontologies and use them in the distributed and open environment of the SemanticWeb. However, such interoperability is not straightforward due to the high heterogeneity in such technologies. This chapter describes the problem of semantic technology interoperability from two different perspectives. First, from a theoretical perspective by presenting an overview of the different factors that affect interoperability and, second, from a practical perspective by reusing evaluation methods and applying them to six current semantic technologies in order to assess their interoperability.

The Innovation Sources in Software Engineering: A Systematic Literature Review

During the last century many researches on the business, marketing and technology fields have developed the innovation research line and large amount of knowledge can be found in the literature. Currently, the importance of systematic and openness approaches to manage the available innovation sources is well established in many knowledge fields. Also in the software engineering sector, where the organizations need to absorb and to exploit as much innovative ideas as possible to get success in the current competitive environment. This Master Thesis presents an study related with the innovation sources in the software engineering eld. The main research goals of this work are the identication and the relevance assessment of the available innovation sources and the understanding of the trends on the innovation sources usage. Firstly, a general review of the literature have been conducted in order to define the research area and to identify research gaps. Secondly, the Systematic Literature Review (SLR) has been proposed as the research method in this work to report reliable conclusions collecting systematically quality evidences about the innovation sources in software engineering field. This contribution provides resources, built-on empirical studies included in the SLR, to support a systematic identication and an adequate exploitation of the innovation sources most suitable in the software engineering field. Several artefacts such as lists, taxonomies and relevance assessments of the innovation sources most suitable for software engineering have been built, and their usage trends in the last decades and their particularities on some countries and knowledge fields, especially on the software engineering, have been researched. This work can facilitate to researchers, managers and practitioners of innovative software organizations the systematization of critical activities on innovation processes like the identication and exploitation of the most suitable opportunities. Innovation researchers can use the results of this work to conduct research studies involving the innovation sources research area. Whereas, organization managers and software practitioners can use the provided outcomes in a systematic way to improve their innovation capability, increasing consequently the value creation in the processes that they run to provide products and services useful to their environment. In summary, this Master Thesis research the innovation sources in the software engineering field, providing useful resources to support an effective innovation sources management. Moreover, several aspects should be deeply study to increase the accuracy of the presented results and to obtain more resources built-on empirical knowledge. It can be supported by the INno- vation SOurces MAnagement (InSoMa) framework, which is introduced in this work in order to encourage openness and systematic approaches to identify and to exploit the innovation sources in the software engineering field.

Technology of bare tether current collection

The outstanding problem for useful applications of electrodynamic tethers is obtaining sufficient electron current from the ionospheric plasma. Bare tether collectors, in which the conducting tether itself, left uninsulated over kilometers of its length, acts as the collecting anode, promise to attain currents of 10 A or more from reasonably sized systems. Current collection by a bare tether is also relatively insensitive to drops in electron density, which are regularly encountered on each revolution of an orbit. This makes nighttime operation feasible. We show how the bare tether's high efficiency of current collection and ability to adjust to density variations follow from the orbital motion limited collection law of thin cylinders. We consider both upwardly deployed (power generation mode) and downwardly deployed (reboost mode) tethers, and present results that indicate how bare tether systems would perform as their magnetic and plasma environment varies in low earth orbit.

Multi-agent location system in wireless networks

In this paper we propose a flexible Multi-Agent Architecture together with a methodology for indoor location which allows us to locate any mobile station (MS) such as a Laptop, Smartphone, Tablet or a robotic system in an indoor environment using wireless technology. Our technology is complementary to the GPS location finder as it allows us to locate a mobile system in a specific room on a specific floor using the Wi-Fi networks. The idea is that any MS will have an agent known at a Fuzzy Location Software Agent (FLSA) with a minimum capacity processing at its disposal which collects the power received at different Access Points distributed around the floor and establish its location on a plan of the floor of the building. In order to do so it will have to communicate with the Fuzzy Location Manager Software Agent (FLMSA). The FLMSAs are local agents that form part of the management infrastructure of the Wi-Fi network of the Organization. The FLMSA implements a location estimation methodology divided into three phases (measurement, calibration and estimation) for locating mobile stations (MS). Our solution is a fingerprint-based positioning system that overcomes the problem of the relative effect of doors and walls on signal strength and is independent of the network device manufacturer. In the measurement phase, our system collects received signal strength indicator (RSSI) measurements from multiple access points. In the calibration phase, our system uses these measurements in a normalization process to create a radio map, a database of RSS patterns. Unlike traditional radio map-based methods, our methodology normalizes RSS measurements collected at different locations on a floor. In the third phase, we use Fuzzy Controllers to locate an MS on the plan of the floor of a building. Experimental results demonstrate the accuracy of the proposed method. From these results it is clear that the system is highly likely to be able to locate an MS in a room or adjacent room.

Monitoring visual attention on a neurorehabilitation environment based on interactive video

The use of new technologies in neurorehabilitation has led to higher intensity rehabilitation processes, extending therapies in an economically sustainable way. Interactive Video (IV) technology allows therapists to work with virtual environments that reproduce real situations. In this way, patients deal with Activities of the Daily Living (ADL) immersed within enhanced environments [1]. These rehabilitation exercises, which focus in re-learning lost functions, will try to modulate the neural plasticity processes [2]. This research presents a system where a neurorehabilitation IV-based environment has been integrated with an eye-tracker device in order to monitor and to interact using visual attention. While patients are interacting with the neurorehabilitation environment, their visual behavior is closely related with their cognitive state, which in turn mirrors the brain damage condition suffered by them [3] [4]. Patients’ gaze data can provide knowledge on their attention focus and their cognitive state, as well as on the validity of the rehabilitation tasks proposed [5].

AMELIE: Authoring Multimedia-Enhanced Learning Interactive Environment for medical contents

This paper presents the AMELIE Authoring Tool for medical e-learning applications. The tool allows for the creation of enhanced-video based didactic contents, and can be adjusted to any number of platforms and applications. Validation provides preliminary good results on its acceptance and usefulness.

Lighting technology

From the economic point of view, additional lighting at night causes enormous costs and is responsible for using up a massive percentage of the worlds energy resources. During recent years, development trends in the field of LED technology have paved the way for novel concepts impacting on the subject oflight. In this way, the abovementioned issues can be greatly reduced resulting in a better balance between the environment and human needs.

Marco de Gobernanza de TI para empresas PyMEs – SMEsITGF

La tecnología de la información y su utilización en las empresas ha sido y es un elemento de debate ya que las organizaciones cuentan con grandes éxitos y grandes fracasos. Gran parte de estos últimos asociados a una falta de visión estratégica integral en relación a la utilización de TI en la organización lo que ha dado lugar al área del conocimiento llamada Gobernanza de TI y a la publicación de numerosos marcos y estándares. Un campo sensible y económicamente muy importante tanto para Uruguay como a nivel mundial son las empresas medianas y pequeñas (PyMEs), las que no logran aplicar de manera efectiva los marcos y estándares, es por esta razón que el objetivo final de esta tesis es el de construir un marco que permita a las PyMEs incorporar un marco efectivo para gobernar y gestionar TI adecuadamente obteniendo el valor esperado de las inversiones realizadas. Para alcanzar este objetivo general se ha realizado un estudio de campo que permita conocer la situación de la gobernanza y la gestión de TI en PyMEs del Uruguay; a partir de este estudio se pudo analizar cuáles son los factores más significativos que no permiten la correcta aplicación de buenas prácticas de gobernanza de TI en éstas empresas. Los resultados encontrados llevaron a la construcción de un marco de gobernanza de TI con foco en PyMEs, a la definición de un modelo de madurez asociado al marco y a una guía de implantación. En el marco de gobernanza propuesto, compatible con el estándar ISO/IEC 38500:2008, se han fortalecido los procesos que, por las características propias de las PyMEs presentan debilidades estructurales y se han reducido o eliminado aquellos que por las mismas razones no son aplicables a este tipo de organización. Finalmente se validaron los resultados en un entorno empresarial definiendo un estudio de caso. Los resultados obtenidos con una mejora porcentual consolidada del 46% en el conjunto de indicadores definidos llevan a considerar que la aplicación del marco fue exitosa. Por ser un estudio de caso único, los resultados no deben ser generalizados y una oportunidad de trabajo futuro es replicar el mismo estudio en otras empresas. ABSTRACT Information technology (IT) and its use in the enterprise context is a discussion element because organizations have numerous successes and failures using it. Most of the IT failed projects have a lack of integral strategic vision in relation with IT use in the organization. This fact has resulted in the IT Governance (ITG) area of knowledge. A large number of standards and frameworks have been published in relation with it. Small and medium enterprises (SMEs) are an important and sensible field in all economies around the world, particularly in Uruguay, an underdeveloped country of South America. Commonly, SMEs cannot apply successfully ITG frameworks because of the intrinsic complexity or because a lack of knowledge and culture respect this field, so the objective of this thesis is build a framework that allows SMEs to incorporate an effective framework to govern and manage IT properly, helping enterprises get the expected value of its IT investments. In a first place, has been conducted a field study to know the quality of actual practices relatively to the ITG and IG management in Uruguayan SMEs. With the obtained results in the study we can make a diagnostic of the most significant factors that prevent the proper application of good IT governance practices in these companies. The obtained results were the inputs to the definition of a IT governance framework with focus in SMEs, a maturity model associated with it and a implementation guide. The proposed framework is ISO/IEC 38500 standard compatible always with an SME vision so, sensible and weak processes have been strengthened and other ones have been eliminated because have no application in these type of organization. Finally the results were validated in a business environment by defining a case study. The results obtained with a consolidated percentage improvement of 46% in the defined set of indicators suggest that the implementation of the framework was successful. As a single case study, the results should not be generalized and an opportunity for future work is to replicate the same study in other companies.

Urban agriculture in the new framework of green cities.

Urban Agriculture was a common practice in the old times. However after a period of low interest by urban population there is a movement of renaissance of urban agriculture especially in the new megalopolis. It is important to understand the role of UA in the new framework, and the interface of urban and rural agricultures, with their comparative advantages. Thus, we describe the impact of UA in several scenarios: political, socioeconomic and environmental. As a consequence several actions should be developed for improving the situation, with the stimulus to UA: urban planning, food value chain, appropriate technology, education and extension services, entertainment and leisure, selection of botanic varieties and agrochemical inputs, design and landscape and good farming practices. As a complement, there is an analysis of the Urban Greening Value Organization in our society. In the paper there is a description of the situation of urban agriculture in Spain (located mainly in roofs, walls, indoor and ground places) the existence of local regulations, barriers and opportunities in the new situation. Due to the social dimension of urban agriculture there are some comments about the role of the more significant stakeholders, and the goals and the structure of the neighbor communities.

AMELIE: Authoring Multimedia-Enhanced Learning Interactive Environment for medical contents

This paper presents the AMELIE Authoring Tool for medical e-learning applications. The tool allows for the creation of enhanced-video based didactic contents, and can be adjusted to any number of platforms and applications. Validation provides preliminary good results on its acceptance and usefulness.

Implementación de un cambio de estrategia en un banco español para su optimización y ventaja competitiva

En la situación actual, en la que la inestabilidad económica es un hecho, se plantea analizar y estudiar el estado de las entidades financieras. El estudio a realizar se circunscribe únicamente al ámbito nacional, debido a la idiosincrasia de los bancos. Para conocer el entorno en el que se mueven los bancos nacionales, se analiza en primer lugar el estado financiero de los países más relevantes a nivel internacional, para posteriormente estudiar la situación económica de España, especialmente en el sector bancario. Se pretende establecer el marco en el que se mueve dicho sector, para poder tener toda la información necesaria para entender no sólo los problemas que afectan a estas entidades, sino también para ver que es necesario un cambio para que estas organizaciones puedan evolucionar y desarrollarse. Una vez detallado el entorno en el que se tienen que mover los bancos, se detallan los principales motivos por los que han perdido credibilidad de cara a los clientes y a los organismos internacionales responsables de velar por la correcta ejecución de las operaciones bancarias, conforme a unas normativas ya establecidas. Se han mencionado algunos ejemplos significativos y con gran repercusión social. No se entra a detallar cada uno de los casos, el objetivo es mostrar que este tipo de actuaciones no sólo perjudican a la propia entidad sino que repercuten en todo el ámbito financiero nacional. Al profundizar en los motivos que han llevado a los bancos a la situación que sufren actualmente, se ve que mantener el mismo método de trabajo no es sostenible a largo plazo; por ello, se plantea un cambio en su estrategia, en concreto un cambio en el modelo de cultura organizacional. Se toma como modelo el empleado en otras empresas, principalmente orientales, por su carácter innovador y por estar más alineadas con las nuevas necesidades y requerimientos de los clientes actualmente. La evolución de las tecnologías ha supuesto un cambio disruptivo en la forma de hacer negocios: algo que debe adoptar la banca para poder, no sólo competir, sino sobrevivir. El cambio de modelo estratégico ha de iniciarse en la Alta Dirección, para propagarse posteriormente al resto de la organización. Al tratarse de un cambio de gran envergadura, su completa implantación llevará años, por lo que es imprescindible realizar un seguimiento y una revisión continua del mismo. Finalmente se comentan las ventajas que el banco conseguirá con este cambio. Éstas abarcan la recuperación de la confianza de los clientes, pasando por una modernización (necesaria en cualquier caso), para completarse con un incremento de los beneficios económicos, que no deja de ser uno de los motores de los bancos. ---ABSTRACT---Nowadays, the economic instability is a fact, so in this project we have studied and analysed the status of financial institutions. This study is limited to the national environment, due to the idiosyncrasy of the banks. In order to understand the environment in which national banks moved, firstly it has been analysed the financial status of the most relevant countries internationally, to study later the economic status of Spain, especially in the banking sector. The aim is to establish a framework in which the sector moves, to have at the end all the necessary information to understand, not only the issues that are affecting to this entities, but also to realize that a change is necessary for their progress and develop. Once detailed the environment in which the banks have to move, it is detailed the main reasons that have lead them to lose credibility with customers, and with international agencies responsible for ensuring the correct execution of banking operations. These operations must be done under established regulations. It has been mentioned some significant examples of mistakes that have had a social impact. It has not been detailed each outrageous, the objective is to show that this kind of actions not only hurt the institution itself, but also affect the entire national financial sector. Into the reasons that have led banks to the actual situation, it can be seen that keeping the same method of working is not sustainable in the long term; therefore, a change of strategy is proposed, more specifically a change in the model of organizational culture. The reference model has been one used by other companies, mainly eastern companies, due to its innovation and its capability to be aligned with the changing needs and requirements of customers nowadays. The evolution of technology has been a disruptive change in the way of doing business: something to be taken by the bank, not only to compete but also to survive. The strategic model change must start with the compromise of CEO’s, and later must be spread to the rest of the organization. It is a major change, so its full implementation will take years, so, it is basic to carry out continuous reviews. Finally, the advantages that the bank will get with this change are discussed. These advantages include recovery of customer confidence, through modernization (something needed anyway), to be enriched by an increase in economic benefits, the engine of the banks.

Survey on student motivation and approval of educational environment at Universidad Politécnica de Madrid within the European Higher Education area implementation

A recent study elaborated by Vicerrectorado de Ordenación Académica y Planificación Estratégica of Technical University of Madrid (UPM) defines the satisfaction of the university student body as "the response that the University offers to the expectations and demands of service of the students, considered in a general way ". Besides an indicator of academic and institutional insertion of the student, the assessment of student engagement allows us to adapt the academic offer and the extension services of the University to the real needs of the students. The process of convergence towards the European Higher Education Area (EHEA) raises the need to form in competitions, that is to say, of developing in our students capacities and knowledge beyond the purely theoretical-practical thing. Therefore, the perception and experience of the educational process and environment by the students is an important issue to be addressed to accomplish their expectations and achieve a curriculum accordingly to EHEA expectations. The present study aims to explore the student motivation and approval of the educational environment at the UPM. To this end a total of 97 students enrolled in the undergraduate program of Civil Engineering, Computer Engineering and Agronomic Engineering at UPM were surveyed. The survey consisted of 40 questions divided in three blocks. The first one of 20 questions of personal character in that they were gathering, besides the sex and the age, the degree of fulfilment, implication and dedication with the institution and the academic tasks. In the second block we identify 10 questions related to the perception of the student on the teaching quality, and finally a block of 10 questions regarding the Bologna Process. The students personal motivation was moderately high, with a score of 3.6 (all scores are provided on a 5-point scale), being the most valuable items obtaining a university degree (4,3) and the friendship between students (4,2). Any significant difference was shown between sexes (P=0.23) since the averages for this block of questions were of 3.7±0.3 and 3.5±0.4 for women and men respectively. The students are moderately satisfied with their graduate studies with an average score of 3,2, being the questions that reflect a minor satisfaction the research profile of the teachers (2,8) and the organization of the Schools (2,9). The best valued questions are related to the usefulness and quality of the degrees, with 3,5 and 3,4 respectively, and to the interest of the courses within the degree (3,4). For sexes, the results of this block of questions are similar (3.1±0.3 and 3.2±0.3 for men and women respectively=0.79). Also, there were no differences (P=0.39) between the students who arrange work and studies or do not work (3.1±0.2 and 3.2±0.3 respectively). In conclusion, students at UPM present an acceptable degree of motivation and satisfaction with regard to the studies and services that offer their respective Schools. Both characteristics receive the same value both for men and for women and so much for students who arrange work and studies as for those who devote themselves only to studying. In a significant way, students who are more engaged and are in-class attendants present the major degree of satisfaction.Overall, there is a great lack of information regarding the Bologna Process. In fact to the majority, they would like to know more on what it is, what it means and what changes will involve its implementation.

Wireless communication enhancement methods for mobile robots in radiation environments

En entornos hostiles tales como aquellas instalaciones científicas donde la radiación ionizante es el principal peligro, el hecho de reducir las intervenciones humanas mediante el incremento de las operaciones robotizadas está siendo cada vez más de especial interés. CERN, la Organización Europea para la Investigación Nuclear, tiene alrededor de unos 50 km de superficie subterránea donde robots móviles controlador de forma remota podrían ayudar en su funcionamiento, por ejemplo, a la hora de llevar a cabo inspecciones remotas sobre radiación en los diferentes áreas destinados al efecto. No solo es preciso considerar que los robots deben ser capaces de recorrer largas distancias y operar durante largos periodos de tiempo, sino que deben saber desenvolverse en los correspondientes túneles subterráneos, tener en cuenta la presencia de campos electromagnéticos, radiación ionizante, etc. y finalmente, el hecho de que los robots no deben interrumpir el funcionamiento de los aceleradores. El hecho de disponer de un sistema de comunicaciones inalámbrico fiable y robusto es esencial para la correcta ejecución de las misiones que los robots deben afrontar y por supuesto, para evitar tales situaciones en las que es necesario la recuperación manual de los robots al agotarse su energía o al perder el enlace de comunicaciones. El objetivo de esta Tesis es proveer de las directrices y los medios necesarios para reducir el riesgo de fallo en la misión y maximizar las capacidades de los robots móviles inalámbricos los cuales disponen de almacenamiento finito de energía al trabajar en entornos peligrosos donde no se dispone de línea de vista directa. Para ello se proponen y muestran diferentes estrategias y métodos de comunicación inalámbrica. Teniendo esto en cuenta, se presentan a continuación los objetivos de investigación a seguir a lo largo de la Tesis: predecir la cobertura de comunicaciones antes y durante las misiones robotizadas; optimizar la capacidad de red inalámbrica de los robots móviles con respecto a su posición; y mejorar el rango operacional de esta clase de robots. Por su parte, las contribuciones a la Tesis se citan más abajo. El primer conjunto de contribuciones son métodos novedosos para predecir el consumo de energía y la autonomía en la comunicación antes y después de disponer de los robots en el entorno seleccionado. Esto es importante para proporcionar conciencia de la situación del robot y evitar fallos en la misión. El consumo de energía se predice usando una estrategia propuesta la cual usa modelos de consumo provenientes de diferentes componentes en un robot. La predicción para la cobertura de comunicaciones se desarrolla usando un nuevo filtro de RSS (Radio Signal Strength) y técnicas de estimación con la ayuda de Filtros de Kalman. El segundo conjunto de contribuciones son métodos para optimizar el rango de comunicaciones usando novedosas técnicas basadas en muestreo espacial que son robustas frente a ruidos de campos de detección y radio y que proporcionan redundancia. Se emplean métodos de diferencia central finitos para determinar los gradientes 2D RSS y se usa la movilidad del robot para optimizar el rango de comunicaciones y la capacidad de red. Este método también se valida con un caso de estudio centrado en la teleoperación háptica de robots móviles inalámbricos. La tercera contribución es un algoritmo robusto y estocástico descentralizado para la optimización de la posición al considerar múltiples robots autónomos usados principalmente para extender el rango de comunicaciones desde la estación de control al robot que está desarrollando la tarea. Todos los métodos y algoritmos propuestos se verifican y validan usando simulaciones y experimentos de campo con variedad de robots móviles disponibles en CERN. En resumen, esta Tesis ofrece métodos novedosos y demuestra su uso para: predecir RSS; optimizar la posición del robot; extender el rango de las comunicaciones inalámbricas; y mejorar las capacidades de red de los robots móviles inalámbricos para su uso en aplicaciones dentro de entornos peligrosos, que como ya se mencionó anteriormente, se destacan las instalaciones científicas con emisión de radiación ionizante. En otros términos, se ha desarrollado un conjunto de herramientas para mejorar, facilitar y hacer más seguras las misiones de los robots en entornos hostiles. Esta Tesis demuestra tanto en teoría como en práctica que los robots móviles pueden mejorar la calidad de las comunicaciones inalámbricas mediante la profundización en el estudio de su movilidad para optimizar dinámicamente sus posiciones y mantener conectividad incluso cuando no existe línea de vista. Los métodos desarrollados en la Tesis son especialmente adecuados para su fácil integración en robots móviles y pueden ser aplicados directamente en la capa de aplicación de la red inalámbrica. ABSTRACT In hostile environments such as in scientific facilities where ionising radiation is a dominant hazard, reducing human interventions by increasing robotic operations are desirable. CERN, the European Organization for Nuclear Research, has around 50 km of underground scientific facilities, where wireless mobile robots could help in the operation of the accelerator complex, e.g. in conducting remote inspections and radiation surveys in different areas. The main challenges to be considered here are not only that the robots should be able to go over long distances and operate for relatively long periods, but also the underground tunnel environment, the possible presence of electromagnetic fields, radiation effects, and the fact that the robots shall in no way interrupt the operation of the accelerators. Having a reliable and robust wireless communication system is essential for successful execution of such robotic missions and to avoid situations of manual recovery of the robots in the event that the robot runs out of energy or when the robot loses its communication link. The goal of this thesis is to provide means to reduce risk of mission failure and maximise mission capabilities of wireless mobile robots with finite energy storage capacity working in a radiation environment with non-line-of-sight (NLOS) communications by employing enhanced wireless communication methods. Towards this goal, the following research objectives are addressed in this thesis: predict the communication range before and during robotic missions; optimise and enhance wireless communication qualities of mobile robots by using robot mobility and employing multi-robot network. This thesis provides introductory information on the infrastructures where mobile robots will need to operate, the tasks to be carried out by mobile robots and the problems encountered in these environments. The reporting of research work carried out to improve wireless communication comprises an introduction to the relevant radio signal propagation theory and technology followed by explanation of the research in the following stages: An analysis of the wireless communication requirements for mobile robot for different tasks in a selection of CERN facilities; predictions of energy and communication autonomies (in terms of distance and time) to reduce risk of energy and communication related failures during missions; autonomous navigation of a mobile robot to find zone(s) of maximum radio signal strength to improve communication coverage area; and autonomous navigation of one or more mobile robots acting as mobile wireless relay (repeater) points in order to provide a tethered wireless connection to a teleoperated mobile robot carrying out inspection or radiation monitoring activities in a challenging radio environment. The specific contributions of this thesis are outlined below. The first sets of contributions are novel methods for predicting the energy autonomy and communication range(s) before and after deployment of the mobile robots in the intended environments. This is important in order to provide situational awareness and avoid mission failures. The energy consumption is predicted by using power consumption models of different components in a mobile robot. This energy prediction model will pave the way for choosing energy-efficient wireless communication strategies. The communication range prediction is performed using radio signal propagation models and applies radio signal strength (RSS) filtering and estimation techniques with the help of Kalman filters and Gaussian process models. The second set of contributions are methods to optimise the wireless communication qualities by using novel spatial sampling based techniques that are robust to sensing and radio field noises and provide redundancy features. Central finite difference (CFD) methods are employed to determine the 2-D RSS gradients and use robot mobility to optimise the communication quality and the network throughput. This method is also validated with a case study application involving superior haptic teleoperation of wireless mobile robots where an operator from a remote location can smoothly navigate a mobile robot in an environment with low-wireless signals. The third contribution is a robust stochastic position optimisation algorithm for multiple autonomous relay robots which are used for wireless tethering of radio signals and thereby to enhance the wireless communication qualities. All the proposed methods and algorithms are verified and validated using simulations and field experiments with a variety of mobile robots available at CERN. In summary, this thesis offers novel methods and demonstrates their use to predict energy autonomy and wireless communication range, optimise robots position to improve communication quality and enhance communication range and wireless network qualities of mobile robots for use in applications in hostile environmental characteristics such as scientific facilities emitting ionising radiations. In simpler terms, a set of tools are developed in this thesis for improving, easing and making safer robotic missions in hostile environments. This thesis validates both in theory and experiments that mobile robots can improve wireless communication quality by exploiting robots mobility to dynamically optimise their positions and maintain connectivity even when the (radio signal) environment possess non-line-of-sight characteristics. The methods developed in this thesis are well-suited for easier integration in mobile robots and can be applied directly at the application layer of the wireless network. The results of the proposed methods have outperformed other comparable state-of-the-art methods.

Bare-tape scaling laws for de-orbit missions in a space debris environment

El entorno espacial actual hay un gran numero de micro-meteoritos y basura espacial generada por el hombre, lo cual plantea un riesgo para la seguridad de las operaciones en el espacio. La situación se agrava continuamente a causa de las colisiones de basura espacial en órbita, y los nuevos lanzamientos de satélites. Una parte significativa de esta basura son satélites muertos, y fragmentos de satélites resultantes de explosiones y colisiones de objetos en órbita. La mitigación de este problema se ha convertido en un tema de preocupación prioritario para todas las instituciones que participan en operaciones espaciales. Entre las soluciones existentes, las amarras electrodinámicas (EDT) proporcionan un eficiente dispositivo para el rápido de-orbitado de los satélites en órbita terrestre baja (LEO), al final de su vida útil. El campo de investigación de las amarras electrodinámicas (EDT) ha sido muy fructífero desde los años 70. Gracias a estudios teóricos, y a misiones para la demostración del funcionamiento de las amarras en órbita, esta tecnología se ha desarrollado muy rápidamente en las últimas décadas. Durante este período de investigación, se han identificado y superado múltiples problemas técnicos de diversa índole. Gran parte del funcionamiento básico del sistema EDT depende de su capacidad de supervivencia ante los micro-meteoritos y la basura espacial. Una amarra puede ser cortada completamente por una partícula cuando ésta tiene un diámetro mínimo. En caso de corte debido al impacto de partículas, una amarra en sí misma, podría ser un riesgo para otros satélites en funcionamiento. Por desgracia, tras varias demostraciones en órbita, no se ha podido concluir que este problema sea importante para el funcionamiento del sistema. En esta tesis, se presenta un análisis teórico de la capacidad de supervivencia de las amarras en el espacio. Este estudio demuestra las ventajas de las amarras de sección rectangular (cinta), en cuanto a la probabilidad de supervivencia durante la misión, frente a las amarras convencionales (cables de sección circular). Debido a su particular geometría (longitud mucho mayor que la sección transversal), una amarra puede tener un riesgo relativamente alto de ser cortado por un único impacto con una partícula de pequeñas dimensiones. Un cálculo analítico de la tasa de impactos fatales para una amarra cilindrica y de tipo cinta de igual longitud y masa, considerando el flujo de partículas de basura espacial del modelo ORDEM2000 de la NASA, muestra mayor probabilidad de supervivencia para las cintas. Dicho análisis ha sido comparado con un cálculo numérico empleando los modelos de flujo el ORDEM2000 y el MASTER2005 de ESA. Además se muestra que, para igual tiempo en órbita, una cinta tiene una probabilidad de supervivencia un orden y medio de magnitud mayor que una amarra cilindrica con igual masa y longitud. Por otra parte, de-orbitar una cinta desde una cierta altitud, es mucho más rápido, debido a su mayor perímetro que le permite capturar más corriente. Este es un factor adicional que incrementa la probabilidad de supervivencia de la cinta, al estar menos tiempo expuesta a los posibles impactos de basura espacial. Por este motivo, se puede afirmar finalmente y en sentido práctico, que la capacidad de supervivencia de la cinta es bastante alta, en comparación con la de la amarra cilindrica. El segundo objetivo de este trabajo, consiste en la elaboración de un modelo analítico, mejorando la aproximación del flujo de ORDEM2000 y MASTER2009, que permite calcular con precisión, la tasa de impacto fatal al año para una cinta en un rango de altitudes e inclinaciones, en lugar de unas condiciones particulares. Se obtiene el numero de corte por un cierto tiempo en función de la geometría de la cinta y propiedades de la órbita. Para las mismas condiciones, el modelo analítico, se compara con los resultados obtenidos del análisis numérico. Este modelo escalable ha sido esencial para la optimización del diseño de la amarra para las misiones de de-orbitado de los satélites, variando la masa del satélite y la altitud inicial de la órbita. El modelo de supervivencia se ha utilizado para construir una función objetivo con el fin de optimizar el diseño de amarras. La función objectivo es el producto del cociente entre la masa de la amarra y la del satélite y el numero de corte por un cierto tiempo. Combinando el modelo de supervivencia con una ecuación dinámica de la amarra donde aparece la fuerza de Lorentz, se elimina el tiempo y se escribe la función objetivo como función de la geometría de la cinta y las propietades de la órbita. Este modelo de optimización, condujo al desarrollo de un software, que esta en proceso de registro por parte de la UPM. La etapa final de este estudio, consiste en la estimación del número de impactos fatales, en una cinta, utilizando por primera vez una ecuación de límite balístico experimental. Esta ecuación ha sido desarollada para cintas, y permite representar los efectos tanto de la velocidad de impacto como el ángulo de impacto. Los resultados obtenidos demuestran que la cinta es altamente resistente a los impactos de basura espacial, y para una cinta con una sección transversal definida, el número de impactos críticos debidos a partículas no rastreables es significativamente menor. ABSTRACT The current space environment, consisting of man-made debris and tiny meteoroids, poses a risk to safe operations in space, and the situation is continuously deteriorating due to in-orbit debris collisions and to new satellite launches. Among these debris a significant portion is due to dead satellites and fragments of satellites resulted from explosions and in-orbit collisions. Mitigation of space debris has become an issue of first concern for all the institutions involved in space operations. Bare electrodynamic tethers (EDT) can provide an efficient mechanism for rapid de-orbiting of defunct satellites from low Earth orbit (LEO) at end of life. The research on EDT has been a fruitful field since the 70’s. Thanks to both theoretical studies and in orbit demonstration missions, this technology has been developed very fast in the following decades. During this period, several technical issues were identified and overcome. The core functionality of EDT system greatly depends on their survivability to the micrometeoroids and orbital debris, and a tether can become itself a kind of debris for other operating satellites in case of cutoff due to particle impact; however, this very issue is still inconclusive and conflicting after having a number of space demonstrations. A tether can be completely cut by debris having some minimal diameter. This thesis presents a theoretical analysis of the survivability of tethers in space. The study demonstrates the advantages of tape tethers over conventional round wires particularly on the survivability during the mission. Because of its particular geometry (length very much larger than cross-sectional dimensions), a tether may have a relatively high risk of being severed by the single impact of small debris. As a first approach to the problem, survival probability has been compared for a round and a tape tether of equal mass and length. The rates of fatal impact of orbital debris on round and tape tether, evaluated with an analytical approximation to debris flux modeled by NASA’s ORDEM2000, shows much higher survival probability for tapes. A comparative numerical analysis using debris flux model ORDEM2000 and ESA’s MASTER2005 shows good agreement with the analytical result. It also shows that, for a given time in orbit, a tape has a probability of survival of about one and a half orders of magnitude higher than a round tether of equal mass and length. Because de-orbiting from a given altitude is much faster for the tape due to its larger perimeter, its probability of survival in a practical sense is quite high. As the next step, an analytical model derived in this work allows to calculate accurately the fatal impact rate per year for a tape tether. The model uses power laws for debris-size ranges, in both ORDEM2000 and MASTER2009 debris flux models, to calculate tape tether survivability at different LEO altitudes. The analytical model, which depends on tape dimensions (width, thickness) and orbital parameters (inclinations, altitudes) is then compared with fully numerical results for different orbit inclinations, altitudes and tape width for both ORDEM2000 and MASTER2009 flux data. This scalable model not only estimates the fatal impact count but has proved essential in optimizing tether design for satellite de-orbit missions varying satellite mass and initial orbital altitude and inclination. Within the frame of this dissertation, a simple analysis has been finally presented, showing the scalable property of tape tether, thanks to the survivability model developed, that allows analyze and compare de-orbit performance for a large range of satellite mass and orbit properties. The work explicitly shows the product of tether-to-satellite mass-ratio and fatal impact count as a function of tether geometry and orbital parameters. Combining the tether dynamic equation involving Lorentz drag with space debris impact survivability model, eliminates time from the expression. Hence the product, is independent of tether de-orbit history and just depends on mission constraints and tether length, width and thickness. This optimization model finally led to the development of a friendly software tool named BETsMA, currently in process of registration by UPM. For the final step, an estimation of fatal impact rate on a tape tether has been done, using for the first time an experimental ballistic limit equation that was derived for tapes and accounts for the effects of both the impact velocity and impact angle. It is shown that tape tethers are highly resistant to space debris impacts and considering a tape tether with a defined cross section, the number of critical events due to impact with non-trackable debris is always significantly low.