New generation wireless communication systems should support the increasing demand for efficient utilization of the electromagnetic spectrum. The Cognitive Radio (CR) paradigm is envisioned as a new technique to realize this goal. Nowadays, Software Defined Radios (SDRs) are the foundations on which the CR will be achieved. In this thesis we implemented an SDR network testbed based on a GNU radio platform. The test network was used to evaluate the actual performance of two methods that attempt to contribute as constituents of a Radio Environment Map (REM). REMs are a new approach to provide situation awareness for CRs. The first technique under analysis was a colouring-based frequency allocation mechanism that optimizes the assignment of frequency channels in the 2.4 GHz band. Its effectiveness was demonstrated using several performance tests in different scenarios and conditions. This study also explores the viability of using our SDR testbed to execute real-time power measurements to estimate the dynamics of indoor radio propagation. This is a preliminary step to obtain complete radio environment awareness, and thus contribute towards realizing the REM and CR approaches. 

This thesis investigates the turbine performance of a particular tidal energy conversion device analysing the hydrodynamic variables based on computational fluid dynamics simulations. Renewable tidal energy technology is undergoing a rapid development due to its advantages and new and creative designs of marine current turbines which are constantly being studied and improved. As a result, incorporating diffusers to accelerate the flow is a method used to increase the efficiency of the turbines. However, this practice has to be evaluated and parameterised to ensure its viability. Therefore, an experimental test of a ducted turbine, carried out in 2010, was selected for analysis with the aim of improving diffuser efficiency without studying the diffuser design but other variables in the system. The advantage of this strategy applied to a particular case is that the knowledge achieved can be used to benefit any diffuser design on many tidal turbines. The diffuser that was used in the 2010 experiment exhibited a low increment in power extracted and the main objective of this thesis arises from the question of how it could be possible to extract much more power using such ducted turbine with the same rotor and diffuser because the interaction of device components and characteristics of water flow causes an impact on the flow field, and therefore in extraction of energy. A methodology based on two hypotheses was developed to understand the influence of diffuser over the flow. The hypotheses addressed two areas: effects produced by a strut characteristic of turbine design and influence of the free surface.

The transport for disabled people at the Rône-Alpes Region constitutes a complex and multi-dimensional system. Numerous actors interact constantly, most of them with conflicting objectives. In this sector, the economic efficiency cannot determine the system performance. As a matter of fact, aspects such us quality of service and human side effects, say pathological or emotional incompatibilities, might play a critical role. In this master thesis we will examine the daily transport of children with disabilities at Lyon urban center in two main phases: 1) a qualitative analysis of the stakeholders, their motivations and interactions 2) a quantitative study to determine the benefit of optimizing the transport system considering passengers constraints with heterogeneous and reconfigurable vehicles. The proposed optimization problem is not yet covered in the scientific literature.

Desde una perspectiva psicosocial, el concepto sobre el cual se han soportado los estudios sobre burnout, en cuerpos de policía, corresponde a la definición establecida por Maslach, entendiendo el síndrome como una respuesta al estrés laboral crónico que se caracteriza porque el individuo desarrolla una idea de fracaso profesional (en especial en relación a las personas hacia las que trabaja), la vivencia de encontrarse emocionalmente agotado y actitudes negativas hacia las personas con las que trabaja (Maslach y Jackson, 1981,1986). Tomado de Gil-Monte y Peiró (1999). La mayor incidencia del síndrome de quemarse por el trabajo se da en profesionales de servicios que prestan una función asistencial o social, generando deterioro en su calidad de vida laboral y con repercusiones sobre la sociedad en general, especialmente en profesionales sanitarios, profesionales de la educación, trabajadores sociales, funcionarios de prisiones o policías (Gil-Monte, Peiró, 1997), como resultado de algunos factores en el trabajo: alto número de usuarios, prevalencia de respuestas negativas por parte de los usuarios y falta de recursos (Maslach, Schaufeli & Leiter, 2001).  Los resultados de las investigaciones adelantadas hasta la fecha, no permiten generalizar características particulares de los componentes de burnout en cuerpos de policía, lo cual ha llevado a que en el desarrollo del presente trabajo se realice un análisis causa-efecto, de los factores situacionales e individuales que han sido estudiados, con el fin de dar elementos de juicio que permitan entender el desarrollo del síndrome en este colectivo. Finalmente, se presentan las conclusiones a las que se ha podido llegar como resultado del aprendizaje en la profundización de este, junto con una propuesta de una agenda futura sobre el estudio del burnout, tanto a nivel teórico como aplicado, con el fin de servir de referente en las organizaciones policiales, que incentive el desarrollo de políticas y programas en la gestión de los recursos humanos dirigidos a ofrecer a los trabajadores recursos efectivos buscando mejorar las condiciones de bienestar individual, grupal y organizacional en este grupo poblacional.

La regularidad de intervalos entre buses ha demostrado mejorar el nivel de servicio de sistemas de transporte público, reduciendo tiempos de espera de pasajeros, balanceando la carga de los buses y logrando ahorros en costos operacionales. Este trabajo evalúa el modelo de optimización desarrollado por Delgado et al. (2012), que controla los intervalos entre buses, a través de su implementación en EMBARQ BRT Simulator, usando datos reales y teniendo en cuenta consideraciones prácticas de implementación. Se adaptó EMBARQ BRT Silmulator para incluir las estrategias de control en la simulación y permitir su interacción con el modelo de optimización que fue modificado para permitir la solución de problemas de gran tamaño. Para estudiar los beneficios de las estrategias de control se usan datos reales de la única línea que opera en el corredor BRT Insurgentes de Ciudad de México D.F.Se definen y evalúan escenarios donde se establecen los beneficios de implementar diferentes esquemas de control en el corredor. Los parámetros estudiados incluyen: (i) intervalo de tiempo entre optimizaciones; (ii) número de paraderos incluidos en la optimización; y (iii) combinación de acciones de control como retención (holding), delimitación de pasajeros a abordar el bus (boarding limits) y la posibilidad de no permitir subidas en determinadas paradas. Para el caso de estudio, la estrategia de sólo holding, optimizando cada 2 minutos y considerando 12 de los 72 paraderos, redujo en 21% los tiempos de espera total percibidos, la variabilidad en 39% y mostró ahorros para el operador del 5% de la flota. Las estrategias que consideran limitaciones prácticas, mostraron beneficios similares a los casos sin ellas, demostrando su factibilidad de implementación en casos reales. Finalmente, se recomienda implementar el modelo en un corredor real, donde se podría usar EMBARQ BRT Simulator para la evaluación de estrategias de control.

Recent technological developments in mechanical investigation techniques and nondestructive monitoring of masonry buildings provide today an amount of information, unthinkable up until yesterday. Likewise the techniques of automated laser survey allow a rapid and precise definition of the geometry of a building, with a level of detail never previously reached. On the other hand, the applications to the modeling of complex masonry historical structures are not as widespread, and constitute an interesting subject of research. Despite the fact that numerical modeling techniques based on the finite element method have progressed considerably, and the computing power available is constantly growing. The difficulties that are encountered are manifold, and reside especially on the absence of well consolidated procedures for the definition of the model and for the management of uncertainties. The Asinelli Tower in Bologna is taken as a case study to define a general methodology for the analysis of historical masonry towers. Using the finite element code DIANA (TNO Diana, Netherlands) the difficulties that are typically encountered in building models of increasing complexity are addressed, proposing a general procedure. The study of the tower, although not directed to the formulation of an explicit judgment on the structural stability, has led to the formulation of an anisotropic cracked masonry model, capable of representing the dynamic behavior of the tower with greater efficiency compared to what is available in the scientific literature.

Usually, an actuary would begin by trying to study a particular consumer insurance pool. In this work, I am working on Colombia and soon, I struggled in having complete and precise information. Indeed, it is a recurrent issue for actuaries studying most emerging countries. The next step would be to estimate the risks an insurance company will have to face in order to create profitable products. I was interested in studying Climatic risks and, since Colombia's weather is interesting. I decided to study the floods in Colombia. Colombian weather is ruled by still unpredictable and random events: El Niño and La Niña that bring droughts and floods. Once again, I quite struggled in having reliable insurance information about the floods since this risk has never been surveyed separately from the overall house damages before 2010. From 2010 to 2012, because of the frequency and the importance of the floods, insurance companies have been trying to study the cost of climatic catastrophes but it was not profitable enough for them to keep on. Indeed, there are not enough people subscribing to house insurances for it to be profitable. Hence, I did not work only on 2010-2012 data because it does not allow me to stand back enough. I worked with the overall house damages data. Finally, from the two previous analysis, an actuary have to adapt his product to the consumer market.

The focus of this study is to build, from the “bottom-up”, a market with artificially intelligent adaptative agents based on the institutional arrangement –monetary policy, regulations, trading conventions– of the Colombian Foreign Exchange Market prevailing between December 1994 and September 1999 in order to determine simple agents´ design, rules and interactions that are sufficient to create interesting behaviours at the macroscopic level – emerging patterns that replicate the properties of the time series from the case study. Tomado del resumen de este documento

Colombia is not a Member State of the Maritime Carriage Conventions currently in force (Hague-Visby Rules and Hamburg Rules) and it is uncertain whether it will ratify the Rotterdam Rules in the upcoming future. Pursuant to the foregoing, the regulation of the contracts of carriage of goods by sea is governed by the Colombian Code of Commerce. Accordingly, the Colombian Code of Commerce provides certain provisions which particularly regulate the carriage of goods by sea under bill of lading. Amongst those provisions, Article 1644 is of paramount significance for the liability of the carrier, considering that it allows in situations where there is no declaration of the value of the goods in the bill of lading, the possibility to apply the limitation of liability agreed by the parties in the carriage contract. However, the case law in Colombia has never concerned the limitation of the carrier’s liability in the context of an international multimodal carriage contract that includes a sea leg. In that respect, Article 16 of Decision 331 of 1993 of the Andean Community sets forth that when a damage or loss to the goods carried occurs in a stage of an international multimodal carriage contract where an international convention applicable or a mandatory national law provides a higher limit of liability for the carrier that the one agreed by the parties in the carriage contract, the limit of liability sets forth either by the international conventions or mandatory national law shall prevail upon the one agreed in the contract. According to the foregoing legal framework, the aim of this master thesis is to determine whether in accordance with Article 16 of Decision 331 of 1993 of the Andean Community and Article 1644 of the Colombian Code of Commerce the limitation of liability provided either in the Hague-Visby Rules or the Hamburg Rules shall apply compulsory in the Colombian jurisdiction in a situation of localized loss or damage to the goods sustained during the sea leg of an international multimodal carriage contract, in order to adjust Colombian jurisdiction with international standards on this subject matter.

Abstract: Many materials of scientific interest show a disordered phase, with their molecules presenting positional disorder, orientational disorder or both. Processes of interest to life also occur in these kind of phases as it is the case of liquid water present in many biochemical problems of interest such as protein folding. The study of these disordered phases is inherently difficult due to their lack of periodicity as in ordered crystals. In this work, molecular dynamics simulations (MD) are used to study two disordered phases: the liquid and the plastic crystal. The configurations obtained by MD are analyzed using different methodologies to obtain insights into the local ordering of the molecules and into their dynamics. The local ordering of the systems is studied using the Euler angles method considering the molecules as rigid bodies. Probability distributions describing the positional and orientational molecular ordering are obtained. These probability distributions are analysed using information theory concepts that provide a deeper understanding of the results. Two systems of interest are studied: hexachloroethane and water. The structure of the liquid and plastic crystal phases of hexacloroethane are investigated and the results from MD and the local ordering analyses are compared to previous works using simulations and neutron diffraction experiments. A Bayesian approach is used in order to obtain the intra-molecular structure of the molecule from the neutron diffraction experimental data, a set of parameters in better agreement with the plastic phase is obtained compared to previous electron diffraction experiments. Liquid water at room conditions is studied on the short range order, presenting a contribution to the ongoing topic of its local structure. The ordering of water at distances beyond the first hydration shell is also studied using the information theory approach. Findings of this work support recent experimental and simulation data showing the existance of long range correlations in water. Finally, plastic crystals phases of water found at high pressures by MD are studied and compared to a high pressure liquid and the ice vii form by comparing their local ordering and dynamics. The methodologies used in this work provide a powerful technique to analyse disordered phases and the results obtained will contribute to the understanding on the structure of such phases. Resumen: Muchos materiales de interés científico se presentan en fases desordenadas, donde las moléculas se encuentran desordenadas posicionalmente, orientacionalmente o ambas. Así mismo, procesos que son importantes para la vida se desarrollan en este tipo de fases. Un ejemplo de ello es el caso del agua líquida que está presente en muchos de los problemas importantes en bioquímica, como el plegamiento de proteínas. El estudio de estas fases desordenadas es inherentemente complejo debido a que no presentan periodicidad en la estructura como en el caso de sólidos cristalinos. En este trabajo se usa la simulación mediante dinámica molecular (MD) para estudiar dos fases desordenadas: el líquido y el cristal plástico. Las configuraciones obtenidas por MD son analizadas usando diferentes metodologías para entender el ordenamiento local y la dinámica de estas fases. El ordenamiento local de los sistemas se estudia usando el método de ángulos de Euler considerando las moléculas como cuerpos rígidos. Se obtienen distribuciones de probabilidad que describen el ordenamiento molecular posicional y orientacional. Estas distribuciones de probabilidad se analizan usando conceptos de teoría de la información que permiten entender mejor los resultados obtenidos. Se estudian dos sistemas de interés: hexacloroetano y agua. La estructura de las fases líquida y de cristal plástico en el hexacloroetano son investigadas y los resultados de MD y de los análisis de ordenamiento local son comparados con resultados previos de simulación y de difracción de neutrones. La estructura intra molecular del hexacloroetano se estudia usando análisis bayesiano haciendo un fit de los datos de difracción de neutrones, el conjunto de parámetros obtenidos mejoran resultados previos de experimentos de difracción por electrones respecto a la fase plástica. Se investiga el orden de corto alcance del agua a temperatura ambiente, contribuyendo al debate sobre su estructura local que es un tema aún abierto. El órden del agua para distancias más allá de los primeros vecinos también se estudia usando el enfoque de la teoría de la información. Los resultados encontrados dan soporte a experimentos y simulaciones recientes que muestran correlaciones de largo alcance en el agua. FInalmente, se estudian las fases plásticas del agua halladas recientemente por MD a altas presiones. Estas fases se comparan con una fase líquida a alta presión y con el hielo vii tanto en su ordenamiento local, como su dinámica. Las metodologías usadas en este trabajo constituyen una herramienta clave para el análisis de fases desordenadas y los resultados obtenidos contribuirán al entendimiento de la estructura de tales fases.