Impacto de los medios sociales en la estrategia de las organizaciones

Dado el impacto que las redes sociales tienen en la vida diaria de los países desarrollados o en vías de desarrollo, éstas han pasado a tener un papel clave en dicho desarrollo social. Dicha consideración no sólo debe centrarse en cómo las personas forman las redes, sino las herramientas que emplean y la forma en la que estas deben ser tratadas por las organizaciones para conseguir una posición preferencial con los usuarios que forman las redes (considerando el creciente número de éstos todos los días). El presente trabajo trata de exponer la diferencia entre medios sociales y redes sociales, estableciendo una diferencia clara entre entre ambos, define lo que son los medios sociales (Social Media en Inglés), qué se debe considerar para que el uso de los mismos tenga una carácter exitoso en sus operaciones y cómo las organizaciones perciben la diferencia competitiva que éstos aportan en sus actividades. Una vez definida, destacamos la importancia de la consideración de estos nuevos medios en las estrategias de la compañías. Para ello, debemos ver el ecosistema de los medios sociales de forma general, y focalizarnos en la relación marca-compañía con el usuario/cliente. La inclusión de los medios sociales en las estrategias de las compañías, primero de forma independiente y, posteriormente, de forma integrada, hace que los modelos de negocio de las compañías se vayan adaptando a los tiempos. Se describe el cambio de paradigma de los modelos de negocio afectados por la introducción de los medios sociales, los elementos y tipos de modelos de negocio que se pueden tener, así como la adaptación de los modelos establecidos a los nuevos modelos. Posteriormente se ve cómo las compañías incluyen los medios sociales en su estrategia, a través de una planificación de medios sociales,partiendo de qué es una estrategia y cómo debe evaluarse. Una vez se ha definido el contexto (qué son los medios sociales, redes sociales, modelo de negocio, estrategia; así como sus características), se definen los bloques funcionales de los medios sociales, con su paralelismo en términos de la estrategia de las compañías, así como se indican determinados factores de éxito para su adopción. Hasta ahora, estamos mirando la organización de forma individual pero, dentro del mercado en el que desarrollan sus actividades, éstas deben ser evaluadas sobre el grado de desarrollo de los medios sociales en sus operaciones; y poder establecer así comparativas, con otras organizaciones, en relación a su grado de implantación. Con dicho objetivo, desarrollaremos un modelo de madurez de medios sociales (Social Media Maturity Model, SMMM o SM3), de forma teórica. ¿Cómo considerar dicho modelo de forma realista?. Basándonos en el método del estudio de casos, se realizará una análisis e investigación de diferentes organizaciones que nos indicará el grado de aproximación del modelo de madurez referenciado, con respecto a la realidad. ABSTRACT Considering the impact that social networks have in the daily life in developed or developing countries, they have come to play a key role in this social development. This consideration should not only focus on how people set up networks, but the tools they use and how these ones should be addressed by organizations to achieve a preferential position with users, forming networks (considering the increasing number of them every day). This work tries to explain the difference between social media and social networking, establishing a clear difference between them, defines what is Social Media, which should be considered for its use has a successful character in their operations and how organizations perceive the competitive edge they bring in their activities. Once they are defined, we remark the importance of considering these new media in companies strategies. For this, we see the social media ecosystem in general, and to focus on brandcompany relationship with the user/client. The inclusion of social media strategies in the companies, independently and in a integrated way, makes the business models of companies evolve along the time. It is described the paradigm shift in business models affected by the introduction of social media, elements and types of business models that can be had, and the adaptation of established models to new models. After that, it’s shown how companies include social media strategy through social media planning and building on what is a strategy and how it should be evaluated. Once the context is defined (what is social media, social networking, business model, strategy, and its features), the functional blocks of social media are defined, with its parallelism in terms of the strategy of companies and specific success factors are indicated. So far, we are looking at the organization individually but within the market in which they operate, they must be evaluated on the degree of development of social media in their operations; and to establish and compare with other organizations in relation to their degree of implementation. With this goal, we will develop a maturity model for social media (Social Media Maturity Model, SMMM or SM3), theoretically. How to consider the model realistically?. Based on the case study method, the analysis and research of different organizations that it will indicate the accuracy of the maturity model referenced with respect to the actually performed.

Urban voids, spaces of great expectations

Study and progress of urban voids. opportunities for new urban design.

Riskmática: Una tecnología educativa desarrollada con Unity

Historically, teachers have always searched for a connection with their students to make education interesting and a vital experience. In the 19th century, pedagogue Johann Heinrich Pestalozzi taught children how to sum using wood blocks. His successors have followed his legacy and today they use a wide variety of media, including board games, in order to reach out to their students. These methods are denominated educational technologies, which are defined as the study and ethical practice of facilitating learning and improving performance by creating, using, and managing appropriate technological processes and resources. With the advent of the information technologies, teachers have at their disposal new media with which they can increase the interest of their students. This technologic revolution is changing the present educational model. The objective of this dissertation is to develop an educational videogame in order to help students learn mathematics. To reach this goal, the videogame has been developed with the game engine Unity as the main tool. Additionally, agile software development methodologies as well as other software engineering techniques have also been used. The result is Riskmatica, an educational videogame based on geographical domination in which knowledge is the best weapon. The players must conquer enemy teritories answering correctly a mathecatical question. Moreover the videogame has the functionality required to configure a new game and input new questions. To conclude, this project has created an educational technology which greatly appeals to students and that can be used by the educators to improve their lessons in mathematics.---RESUMEN---A lo largo de la historia, los educadores siempre han buscado conectar con los alumnos para poder captar su interés y hacer que la educación se convierta en una experiencia vital. El pedagogo Johann Heinrich Pestalozzi conseguía esto en el siglo XIX, enseñando a niños a contar con bloques de madera. Sus sucesores han seguido su legado y hoy en día utilizan variedad de medios con los que motivar a sus alumnos, en algunos casos los juegos de mesa. Estos métodos son denominados tecnologías educativas, que se definen como los estudios y prácticas éticas que facilitan y mejoran la enseñanza, mediante la creación, el uso y el empleo de procesos y recursos tecnológicos. Con el advenimiento de las tecnologías de la información, los educadores tienen a su disposición un nuevo medio con el que llegar al alumnado. Esta revolución tecnológica está cambiando el modelo educativo actual. El objetivo de este proyecto es el de crear un videojuego educativo que ayude a los alumnos a estudiar matemáticas. Para lograrlo se ha utilizado el popular motor de videojuego Unity como herramienta principal. También se han empleado metodologías ágiles de desarrollo además de otras técnicas de ingeniería del software. El resultado es Riskmática, un videojuego educativo de dominación geográfica en el que el arma más eficaz es el conocimiento. Los jugadores deberán conquistar territorios a sus adversarios mediante la respuesta de preguntas de carácter matemático. Además el videojuego cuenta con la funcionalidad necesaria para configurar una partida e introducir nuevas preguntas. Como conlusión, este proyecto ha logrado crear una tecnología educativa muy atractiva para los alumnos con la que los profesores pueden mejorar la enseñanza de las matemáticas.

Haus des Rundfunks en Berlin, de Hans Poelzig, 1930

Poelzig affirmed that the technical ideal consisted of using the least amount of shapes and materials possible. He understood architecture as an art, as the expression of form; In contrast to the indifference of the most widely recognized values of modernism: technical innovation in construction along with the functionality of buildings. The Haus des Rundfunks is a powerful hermetic factory in the shape of a triangle and of uniform height. Mass, geometric rigidity and the absence of textures make up a building which relinquishes expressing the new media, with a perimeter ring consisting of offices and larger spaces that are more characteristic towards their inside. Geometry is used as a means to organize and limit the shapes of the buildings. The arrangement and division of different intercommunicating spaces are subjected to the crudeness of their geometric limits. Interior spaces ranging from the most static to the most dynamic are defined through the qualities of materials and geometries. This turns the spaces into geometric grids which decompose the wall, floor and ceiling planes into fragments, regardless of the constructive reality provided by a metallic frame structure. Its polyhedral lamps enclose artificial and emphasize the value of the grid. Poelzig limits himself to dealing with planes within a closed volume of uniform height, and maintains geometric rigidity compatible with a certain degree of figurativeness. This article tries to bring to life this exemplary building, marked by its passivity and hermetism.

La transformación de las grandes estaciones europeas con la llegada de la Alta Velocidad. El caso de Atocha

La aparición del tren de alta velocidad en Europa en las últimas décadas del siglo XX supuso el resurgir de un medio de transporte en progresivo declive desde la popularización del automóvil y del avión. La decadencia del ferrocarril había supuesto en muchos casos el abandono, o incluso la demolición, de estaciones históricas y el deterioro de su entorno urbano. Como reacción a esa desatención surgió, también en el último cuarto de siglo, una mayor conciencia social preocupada por la conservación del patrimonio construido del ferrocarril. La necesidad de adaptación de las grandes estaciones de ferrocarril para dar servicio al nuevo sistema de transporte, junto con el interés por poner en valor sus construcciones históricas y su céntrico entorno, ha dado como resultado la realización de importantes transformaciones. El objeto de la presente investigación es el estudio de las transformaciones que han sufrido las grandes estaciones europeas del siglo XIX con la llegada del tren de alta velocidad, profundizando de manera especial en el caso más significativo que tenemos en nuestro país: la estación de Atocha. En el ámbito europeo es donde se localizan los ejemplos más relevantes de estaciones que tuvieron gran trascendencia en el siglo XIX y que ahora, con la llegada de la Alta Velocidad, vuelven a recuperar su grandeza. En España, el crecimiento de la Alta Velocidad en los últimos años ha sido extraordinario, hasta situarse como el segundo país del mundo con más kilómetros de líneas de alta velocidad en operación y, en consecuencia, se ha construido un gran número de estaciones adaptadas a este servicio. El caso más notable es el de la estación de Atocha, que desde la llegada del AVE en 1992 hasta el día de hoy, se ha convertido en uno de los complejos ferroviarios más importantes del mundo. El trabajo parte del estudio de otros referentes europeos, como las Gares de París, la estación de St Pancras en Londres y de otras cinco estaciones del centro de Europa –Amsterdam Centraal, Antwerpen Centraal, Köln Hauptbahnhof, Frankfurt (Main) Hauptbahnhof y la Gare de Strasbourg–, para establecer el marco analítico sobre el que se profundiza con la estación de Atocha. El proceso de transformación de la estación de Atocha se ha gestado a través de una serie de proyectos que han ido configurando la estación hasta el momento actual y planteando la previsión de futuro: el proyecto del Plan General de Madrid, el concurso de ideas para el diseño de la estación, la estación de Cercanías, la estación de Alta Velocidad y Largo Recorrido, la ampliación de esta para separar los flujos por niveles, los Estudios Informativos del Nuevo Complejo Ferroviario de la Estación de Atocha y su primera fase de construcción. Estos siete proyectos son objeto de un análisis en tres niveles: análisis cronológico, análisis funcional y análisis formal. La estación de Atocha fue la primera estación histórica europea en sufrir una gran transformación vinculada a la llegada de la Alta Velocidad. Aporta el entendimiento de la estación como un todo y la intermodalidad como sus principales valores, además de la gran mejora urbana que supuso la «operación Atocha», y adolece de ciertas carencias en su desarrollo comercial, vinculadas en parte a la presencia del jardín tropical, y de un pobre espacio en las salas de embarque para los pasajeros de salidas. La estación de Atocha completa su transformación a partir de su renovación funcional, manteniendo la carga simbólica de su historia. De la confrontación del caso de Atocha con otras importantes estaciones europeas resulta la definición de las principales consecuencias de la llegada de la Alta Velocidad a las grandes terminales europeas y la identificación de los elementos clave en su transformación. Las consecuencias principales son: la potenciación de la intermodalidad con otros medios de transporte, el desarrollo comercial no necesariamente destinado a los usuarios de los servicios ferroviarios, y la puesta en valor de la antigua estación y de su entorno urbano. Por su parte, los elementos clave en la transformación de las grandes estaciones tienen que ver directamente con la separación de flujos, el entendimiento de la estación por niveles, la dotación de nuevos accesos laterales y la construcción de una nueva gran cubierta para los nuevos andenes. La preeminencia de unos elementos sobre otros depende del carácter propio de cada estación y de cada país, de la magnitud de la intervención y, también, de la estructura y composición de los equipos encargados del diseño de la nueva estación. En la actualidad, nos encontramos en un momento interesante respecto a las estaciones de Alta Velocidad. Tras el reciente atentado frustrado en el Thalys que viajaba de Ámsterdam a París, se ha acordado establecer controles de identidad y equipajes en todas las estaciones de la red europea de alta velocidad, lo que implicará modificaciones importantes en las grandes estaciones que, probablemente, tomarán el modelo de la estación de Atocha como referencia. ABSTRACT The emergence of the high speed train in Europe in the last few decades of the 20th century represented the resurgence of a means of transport in progressive decline since the popularization of the car and the airplane. The railway decay brought in many cases the abandonment, or even the demolition, of historical stations and the deterioration of its urban environment. In response to that neglect, a greater social awareness towards the preservation of the railway built heritage raised up, also in the last quarter-century. The need for adaptation of the great railway stations to serve the new transport system, along with the interest in enhancing the historical buildings and its central locations, had resulted in important transformations. The subject of current investigation is the study of the transformations that the great 19th century European stations have experienced with the arrival of the high speed rail, deepening in particular in the most significant case we have in Spain: Atocha railway station. At European level is where the most relevant examples of stations which have had a great significance in the 19th century and now, with the arrival of the high speed train, have regain their greatness, are located. In Spain, the growth of the high speed rail over the past few years has been outstanding. Today is the second country in the world with the longest high speed rail network in operation and, therefore, with a great number of new stations adapted to this service. The most remarkable case is Atocha station. Since the arrival of the AVE in 1992, the station has become one of the world's most important railway hub. The research starts with the study of other European reference points, as the Gares of Paris, St Pancras station in London and five other stations of Central Europe –Amsterdam Centraal, Antwerpen Centraal, Köln Hauptbahnhof, Frankfurt (Main) Hauptbahnhof y la Gare de Strasbourg–, to establish the analytical framework that will be deepen with Atocha station. The transformation process of Atocha station has been created through a number of projects that have forged the station to date and have raised the sights in the future: the project of the General Urban Development Plan, the ideas competition for the station design, the Suburban train station, the High Speed and Long Distance station, its enlargement in order to separate passenger flows in different levels, the 'Masterplans' for the new Atocha transport hub and its first phase of construction. These seven projects are under scrutiny at three levels: chronological analysis, functional analysis and formal analysis. Atocha station was the first European historical station to undergo a great transformation tied to the arrival of the high speed rail. It brings the understanding of the station as a whole and the intermodality as its greatest values, besides the great urban improvement of the 'Atocha operation', and suffers from certain shortcomings in its commercial development, partly linked to the presence of the tropical garden, and from a poor space in the departure lounges. Atocha station completes its transformation on the basis of its functional renewal, keeping the symbolic charge of its history. The confrontation of Atocha case with the great European stations results in the definition of the principal consequences of the high speed rail arrival to the great European terminals and the identification of the key elements in its transformation. The principal consequences are: the empowering of the intermodality with other means of transport, of the commercial development, not necessarily intended for railway services users, and the enhancement of the old station and its urban environment. On the other hand, the key elements in the transformation of the great stations are directly related with the separation of passenger flows, the understanding of the station in different levels, the placement of new lateral accesses and the construction of a new deck over the new platforms. The pre-eminence of some elements over the others depends on the particular nature of each station and each country, on the scale of the intervention and also in the structure and composition of the teams in charge of the new station design. Nowadays, this is an interesting time concerning the high speed rail stations. After the recent foiled terrorist attempt in the Thalys train travelling from Amsterdam to Paris, it was agreed to establish passenger and luggage controls in every European high speed rail station. This will mean important changes in these great stations, which probably will take Atocha station's model as a reference.

Simulation model for the study of overhead rail current collector systems dynamics, focused on the design of a new conductor rail

Overhead rigid conductor arrangements for current collection for railway traction have some advantages compared to other, more conventional, energy supply systems. They are simple, robust and easily maintained, not to mention their flexibility as to the required height for installation, which makes them particularly suitable for use in subway infrastructures. Nevertheless, due to the increasing speeds of new vehicles running on modern subway lines, a more efficient design is required for this kind of system. In this paper, the authors present a dynamic analysis of overhead conductor rail systems focused on the design of a new conductor profile with a dynamic behaviour superior to that of the system currently in use. This means that either an increase in running speed can be attained, which at present does not exceed 110 km/h, or an increase in the distance between the rigid catenary supports with the ensuing saving in installation costs. This study has been carried out using simulation techniques. The ANSYS programme has been used for the finite element modelling and the SIMPACK programme for the elastic multibody systems analysis.

New Considerations in the Input Filter Design of a Three-Phase Buck-Type PWM Rectifier for Aircraft Applications

An EMI filter for a three-phase buck-type medium power pulse-width modulation rectifier is designed. This filter considers differential mode noise and complies with MIL-STD-461E for the frequency range of 10kHz to 10MHz. In industrial applications, the frequency range of the standard starts at 150kHz and the designer typically uses a switching frequency of 28kHz because the fifth harmonic is out of the range. This approach is not valid for aircraft applications. In order to design the switching frequency in aircraft applications, the power losses in the semiconductors and the weight of the reactive components should be considered. The proposed design is based on a harmonic analysis of the rectifier input current and an analytical study of the input filter. The classical industrial design does not consider the inductive effect in the filter design because the grid frequency is 50/60Hz. However, in the aircraft applications, the grid frequency is 400Hz and the inductance cannot be neglected. The proposed design considers the inductance and the capacitance effect of the filter in order to obtain unitary power factor at full power. In the optimization process, several filters are designed for different switching frequencies of the converter. In addition, designs from single to five stages are considered. The power losses of the converter plus the EMI filter are estimated at these switching frequencies. Considering overall losses and minimal filter volume, the optimal switching frequency is selected.

Conceptual framework for the design, implementation and validation of psychomotor skills’ assessment systems in minimally invasive surgery

Las técnicas de cirugía de mínima invasión (CMI) se están consolidando hoy en día como alternativa a la cirugía tradicional, debido a sus numerosos beneficios para los pacientes. Este cambio de paradigma implica que los cirujanos deben aprender una serie de habilidades distintas de aquellas requeridas en cirugía abierta. El entrenamiento y evaluación de estas habilidades se ha convertido en una de las mayores preocupaciones en los programas de formación de cirujanos, debido en gran parte a la presión de una sociedad que exige cirujanos bien preparados y una reducción en el número de errores médicos. Por tanto, se está prestando especial atención a la definición de nuevos programas que permitan el entrenamiento y la evaluación de las habilidades psicomotoras en entornos seguros antes de que los nuevos cirujanos puedan operar sobre pacientes reales. Para tal fin, hospitales y centros de formación están gradualmente incorporando instalaciones de entrenamiento donde los residentes puedan practicar y aprender sin riesgos. Es cada vez más común que estos laboratorios dispongan de simuladores virtuales o simuladores físicos capaces de registrar los movimientos del instrumental de cada residente. Estos simuladores ofrecen una gran variedad de tareas de entrenamiento y evaluación, así como la posibilidad de obtener información objetiva de los ejercicios. Los diferentes estudios de validación llevados a cabo dan muestra de su utilidad; pese a todo, los niveles de evidencia presentados son en muchas ocasiones insuficientes. Lo que es más importante, no existe un consenso claro a la hora de definir qué métricas son más útiles para caracterizar la pericia quirúrgica. El objetivo de esta tesis doctoral es diseñar y validar un marco de trabajo conceptual para la definición y validación de entornos para la evaluación de habilidades en CMI, en base a un modelo en tres fases: pedagógica (tareas y métricas a emplear), tecnológica (tecnologías de adquisición de métricas) y analítica (interpretación de la competencia en base a las métricas). Para tal fin, se describe la implementación práctica de un entorno basado en (1) un sistema de seguimiento de instrumental fundamentado en el análisis del vídeo laparoscópico; y (2) la determinación de la pericia en base a métricas de movimiento del instrumental. Para la fase pedagógica se diseñó e implementó un conjunto de tareas para la evaluación de habilidades psicomotoras básicas, así como una serie de métricas de movimiento. La validación de construcción llevada a cabo sobre ellas mostró buenos resultados para tiempo, camino recorrido, profundidad, velocidad media, aceleración media, economía de área y economía de volumen. Adicionalmente, los resultados obtenidos en la validación de apariencia fueron en general positivos en todos los grupos considerados (noveles, residentes, expertos). Para la fase tecnológica, se introdujo el EVA Tracking System, una solución para el seguimiento del instrumental quirúrgico basado en el análisis del vídeo endoscópico. La precisión del sistema se evaluó a 16,33ppRMS para el seguimiento 2D de la herramienta en la imagen; y a 13mmRMS para el seguimiento espacial de la misma. La validación de construcción con una de las tareas de evaluación mostró buenos resultados para tiempo, camino recorrido, profundidad, velocidad media, aceleración media, economía de área y economía de volumen. La validación concurrente con el TrEndo® Tracking System por su parte presentó valores altos de correlación para 8 de las 9 métricas analizadas. Finalmente, para la fase analítica se comparó el comportamiento de tres clasificadores supervisados a la hora de determinar automáticamente la pericia quirúrgica en base a la información de movimiento del instrumental, basados en aproximaciones lineales (análisis lineal discriminante, LDA), no lineales (máquinas de soporte vectorial, SVM) y difusas (sistemas adaptativos de inferencia neurodifusa, ANFIS). Los resultados muestran que en media SVM presenta un comportamiento ligeramente superior: 78,2% frente a los 71% y 71,7% obtenidos por ANFIS y LDA respectivamente. Sin embargo las diferencias estadísticas medidas entre los tres no fueron demostradas significativas. En general, esta tesis doctoral corrobora las hipótesis de investigación postuladas relativas a la definición de sistemas de evaluación de habilidades para cirugía de mínima invasión, a la utilidad del análisis de vídeo como fuente de información y a la importancia de la información de movimiento de instrumental a la hora de caracterizar la pericia quirúrgica. Basándose en estos cimientos, se han de abrir nuevos campos de investigación que contribuyan a la definición de programas de formación estructurados y objetivos, que puedan garantizar la acreditación de cirujanos sobradamente preparados y promocionen la seguridad del paciente en el quirófano. Abstract Minimally invasive surgery (MIS) techniques have become a standard in many surgical sub-specialties, due to their many benefits for patients. However, this shift in paradigm implies that surgeons must acquire a complete different set of skills than those normally attributed to open surgery. Training and assessment of these skills has become a major concern in surgical learning programmes, especially considering the social demand for better-prepared professionals and for the decrease of medical errors. Therefore, much effort is being put in the definition of structured MIS learning programmes, where practice with real patients in the operating room (OR) can be delayed until the resident can attest for a minimum level of psychomotor competence. To this end, skills’ laboratory settings are being introduced in hospitals and training centres where residents may practice and be assessed on their psychomotor skills. Technological advances in the field of tracking technologies and virtual reality (VR) have enabled the creation of new learning systems such as VR simulators or enhanced box trainers. These systems offer a wide range of tasks, as well as the capability of registering objective data on the trainees’ performance. Validation studies give proof of their usefulness; however, levels of evidence reported are in many cases low. More importantly, there is still no clear consensus on topics such as the optimal metrics that must be used to assess competence, the validity of VR simulation, the portability of tracking technologies into real surgeries (for advanced assessment) or the degree to which the skills measured and obtained in laboratory environments transfer to the OR. The purpose of this PhD is to design and validate a conceptual framework for the definition and validation of MIS assessment environments based on a three-pillared model defining three main stages: pedagogical (tasks and metrics to employ), technological (metric acquisition technologies) and analytical (interpretation of competence based on metrics). To this end, a practical implementation of the framework is presented, focused on (1) a video-based tracking system and (2) the determination of surgical competence based on the laparoscopic instruments’ motionrelated data. The pedagogical stage’s results led to the design and implementation of a set of basic tasks for MIS psychomotor skills’ assessment, as well as the definition of motion analysis parameters (MAPs) to measure performance on said tasks. Validation yielded good construct results for parameters such as time, path length, depth, average speed, average acceleration, economy of area and economy of volume. Additionally, face validation results showed positive acceptance on behalf of the experts, residents and novices. For the technological stage the EVA Tracking System is introduced. EVA provides a solution for tracking laparoscopic instruments from the analysis of the monoscopic video image. Accuracy tests for the system are presented, which yielded an average RMSE of 16.33pp for 2D tracking of the instrument on the image and of 13mm for 3D spatial tracking. A validation experiment was conducted using one of the tasks and the most relevant MAPs. Construct validation showed significant differences for time, path length, depth, average speed, average acceleration, economy of area and economy of volume; especially between novices and residents/experts. More importantly, concurrent validation with the TrEndo® Tracking System presented high correlation values (>0.7) for 8 of the 9 MAPs proposed. Finally, the analytical stage allowed comparing the performance of three different supervised classification strategies in the determination of surgical competence based on motion-related information. The three classifiers were based on linear (linear discriminant analysis, LDA), non-linear (support vector machines, SVM) and fuzzy (adaptive neuro fuzzy inference systems, ANFIS) approaches. Results for SVM show slightly better performance than the other two classifiers: on average, accuracy for LDA, SVM and ANFIS was of 71.7%, 78.2% and 71% respectively. However, when confronted, no statistical significance was found between any of the three. Overall, this PhD corroborates the investigated research hypotheses regarding the definition of MIS assessment systems, the use of endoscopic video analysis as the main source of information and the relevance of motion analysis in the determination of surgical competence. New research fields in the training and assessment of MIS surgeons can be proposed based on these foundations, in order to contribute to the definition of structured and objective learning programmes that guarantee the accreditation of well-prepared professionals and the promotion of patient safety in the OR.

The Dynamics of High-Speed Railway Bridges: A Review of Design Issues and New Research for Lateral Dynamics

The dynamic effects of high-speed trains on viaducts are important issues for the design of the structures, as well as for the consideration of safe running conditions for the trains. In this work we start by reviewing the relevance of some basic design aspects. The significance of impact factor envelopes for moving loads is considered first. Resonance which may be achieved for high-speed trains requires dynamic analysis, for which some key aspects are discussed. The relevance of performing a longitudinal distribution of axle loads, the number of modes taken in analysis, and the consideration of vehicle-structure interaction are discussed with representative examples. The lateral dynamic effects of running trains on bridges is of importance for laterally compliant viaducts, such as some very tall structures erected in new high-speed lines. The relevance of this study is mainly for the safety of the traffic, considering both internal actions such as the hunting motion as well as external actions such as wind or earthquakes [1]. These studies require three-dimensional dynamic coupled vehicle-bridge models, and consideration of wheel to rail contact, a phenomenon which is complex and costly to model in detail. We describe here a fully nonlinear coupled model, described in absolute coordinates and incorporated into a commercial finite element framework [2]. The wheel-rail contact has been considered using a FastSim algorithm which provides a compromise between accuracy and computational cost, and captures the main nonlinear response of the contact interface. Two applications are presented, firstly to a vehicle subject to a strong wind gust traversing a bridge, showing the relevance of the nonlinear wheel-rail contact model as well as the dynamic interaction between bridge and vehicle. The second application is to a real HS viaduct with a long continuous deck and tall piers and high lateral compliance [3]. The results show the safety of the traffic as well as the importance of considering features such as track alignment irregularities.

Comments and remarks over classic linear loop-gain method for oscillator design and analysis. New proposed method based on NDF/RRT

Abstract. This paper describes a new and original method for designing oscillators based on the Normalized Determinant Function (NDF) and Return Relations (RRT)- Firstly, a review of the loop-gain method will be performed. The loop-gain method pros, cons and some examples for exploring wrong solutions provided by this method will be shown. This method produces in some cases wrong solutions because some necessary conditions have not been fulfilled. The required necessary conditions to assure a right solution will be described. The necessity of using the NDF or the Transpose Return Relations (RRT), which are related with the True Loop-Gain, to test the additional conditions will be demonstrated. To conclude this paper, the steps for oscillator design and analysis, using the proposed NDF/RRj method, will be presented. The loop-gain wrong solutions will be compared with the NDF/RRj and the accuracy of this method to estimate the oscillation frequency and QL will be demonstrated. Some additional examples of plane reference oscillators (Z/Y/T), will be added and they will be analyzed with the new NDF/RRj proposed method, even these oscillators cannot be analyzed using the classic loop gain method.

Foundations of a New Interaction Paradigm for Immersive 3D Multimedia

Immersion and interaction have been identified as key factors influencing the quality of experience in stereoscopic video systems. The work presented here aims to create a new paradigm for 3D Multimedia consumption exploiting these factors in order to increase user involvement. We use a 5-sided CAVETM environment to support 3D panoramic video reproduction, real-time insertion of synthetic objects into the three-dimensional scene and real-time user interaction with the inserted elements. In this paper we describe our system requirements, functionalities, conceptual design and preliminary implementation results emphasizing the most relevant challenges accomplished. The focus is on three main issues: the generation of stereoscopic video panoramas; the synchronous reproduction of immersive 3D video across multiple screens; and, the real-time insertion algorithm implemented for the integration of synthetic objects into the stereoscopic video. These results have been successfully integrated into the graphic engine managing the operation of the CAVETM infrastructure.

Dynamics of high-speed railway bridges: review of design issues and new research for lateral dynamics

Revisión y puesta al día de la publicaciones relacionadas con el diseño de puentes de ferrocarril de alta velocidad y nuevas investigaciones sobre dinámica lateral.

New Fresnel Köhler optical design: 9-fold photovoltaic concentrator

Non-uniform irradiance patterns created by Concentrated Photovoltaics (CPV) concentrators over Multi-Junction Cells (MJC) can originate significant power losses, especially when there are different spectral irradiance distributions over the different MJC junctions. This fact has an increased importance considering the recent advances in 4 and 5 junction cells. This work presents a new CPV optical design, the 9-fold Fresnel Köhler concentrator, prepared to overcome these effects at high concentrations while maintaining a large acceptance angle, paving the way for a future generation of high efficiency CPV systems of 4 and 5 junction cells.

New Fresnel Köhler Optical Design: 9-Fold Photovoltaic concentrator

Non-uniform irradiance patterns created by Concentrated Photovoltaics (CPV) concentrators over Multi-Junction Cells (MJC) can originate significant power losses, especially when there are different spectral irradiance distributions over the different MJC junctions. This fact has an increased importance considering the recent advances in 4 and 5 junction cells. This work presents a new CPV optical design, the 9-fold Fresnel Köhler concentrator, prepared to overcome these effects at high concentrations while maintaining a large acceptance angle, paving the way for a future generation of high efficiency CPV systems of 4 and 5 junction cells.

A system of systems engineering approach to design new smarter and energy efficient products

The concept of smartness of energy efficient products and systems from a business perspective has been investigated by several authors. The problem of understanding, designing, engineering and governing these technologies requires new concepts. The emergence of these modern technologies causes a myriad of interconnected systems, which are working together to satisfy the necessities of modern life. The problem of understanding, designing, engineering, and governing these technologies requires new concepts. Development of System of System Engineering (SoSE) is an attempt by the systems engineering and science community to fulfill this requirement.