Toward Visual Autonomous Ship Board Landing of a VTOL UAV

In this paper we tackle the problem of landing a helicopter autonomously on a ship deck, using as the main sensor, an on-board colour camera. To create a test-bed, we first adequately simulate the movement of a ship landing platform on the Sea, for different Sea States, for different ships, randomly and realistically enough. We use a commercial parallel robot to get this movement. Once we had this, we developed an accurate and robust computer vision system to measure the pose of the helipad with respect to the on-board camera. To deal with the noise and the possible fails of the computer vision, a state estimator was created. With all of this, we are now able to develop and test a controller that closes the loop and finish the autonomous landing task.

New definitions of margin for multi-class Boosting algorithms

La familia de algoritmos de Boosting son un tipo de técnicas de clasificación y regresión que han demostrado ser muy eficaces en problemas de Visión Computacional. Tal es el caso de los problemas de detección, de seguimiento o bien de reconocimiento de caras, personas, objetos deformables y acciones. El primer y más popular algoritmo de Boosting, AdaBoost, fue concebido para problemas binarios. Desde entonces, muchas han sido las propuestas que han aparecido con objeto de trasladarlo a otros dominios más generales: multiclase, multilabel, con costes, etc. Nuestro interés se centra en extender AdaBoost al terreno de la clasificación multiclase, considerándolo como un primer paso para posteriores ampliaciones. En la presente tesis proponemos dos algoritmos de Boosting para problemas multiclase basados en nuevas derivaciones del concepto margen. El primero de ellos, PIBoost, está concebido para abordar el problema descomponiéndolo en subproblemas binarios. Por un lado, usamos una codificación vectorial para representar etiquetas y, por otro, utilizamos la función de pérdida exponencial multiclase para evaluar las respuestas. Esta codificación produce un conjunto de valores margen que conllevan un rango de penalizaciones en caso de fallo y recompensas en caso de acierto. La optimización iterativa del modelo genera un proceso de Boosting asimétrico cuyos costes dependen del número de etiquetas separadas por cada clasificador débil. De este modo nuestro algoritmo de Boosting tiene en cuenta el desbalanceo debido a las clases a la hora de construir el clasificador. El resultado es un método bien fundamentado que extiende de manera canónica al AdaBoost original. El segundo algoritmo propuesto, BAdaCost, está concebido para problemas multiclase dotados de una matriz de costes. Motivados por los escasos trabajos dedicados a generalizar AdaBoost al terreno multiclase con costes, hemos propuesto un nuevo concepto de margen que, a su vez, permite derivar una función de pérdida adecuada para evaluar costes. Consideramos nuestro algoritmo como la extensión más canónica de AdaBoost para este tipo de problemas, ya que generaliza a los algoritmos SAMME, Cost-Sensitive AdaBoost y PIBoost. Por otro lado, sugerimos un simple procedimiento para calcular matrices de coste adecuadas para mejorar el rendimiento de Boosting a la hora de abordar problemas estándar y problemas con datos desbalanceados. Una serie de experimentos nos sirven para demostrar la efectividad de ambos métodos frente a otros conocidos algoritmos de Boosting multiclase en sus respectivas áreas. En dichos experimentos se usan bases de datos de referencia en el área de Machine Learning, en primer lugar para minimizar errores y en segundo lugar para minimizar costes. Además, hemos podido aplicar BAdaCost con éxito a un proceso de segmentación, un caso particular de problema con datos desbalanceados. Concluimos justificando el horizonte de futuro que encierra el marco de trabajo que presentamos, tanto por su aplicabilidad como por su flexibilidad teórica. Abstract The family of Boosting algorithms represents a type of classification and regression approach that has shown to be very effective in Computer Vision problems. Such is the case of detection, tracking and recognition of faces, people, deformable objects and actions. The first and most popular algorithm, AdaBoost, was introduced in the context of binary classification. Since then, many works have been proposed to extend it to the more general multi-class, multi-label, costsensitive, etc... domains. Our interest is centered in extending AdaBoost to two problems in the multi-class field, considering it a first step for upcoming generalizations. In this dissertation we propose two Boosting algorithms for multi-class classification based on new generalizations of the concept of margin. The first of them, PIBoost, is conceived to tackle the multi-class problem by solving many binary sub-problems. We use a vectorial codification to represent class labels and a multi-class exponential loss function to evaluate classifier responses. This representation produces a set of margin values that provide a range of penalties for failures and rewards for successes. The stagewise optimization of this model introduces an asymmetric Boosting procedure whose costs depend on the number of classes separated by each weak-learner. In this way the Boosting procedure takes into account class imbalances when building the ensemble. The resulting algorithm is a well grounded method that canonically extends the original AdaBoost. The second algorithm proposed, BAdaCost, is conceived for multi-class problems endowed with a cost matrix. Motivated by the few cost-sensitive extensions of AdaBoost to the multi-class field, we propose a new margin that, in turn, yields a new loss function appropriate for evaluating costs. Since BAdaCost generalizes SAMME, Cost-Sensitive AdaBoost and PIBoost algorithms, we consider our algorithm as a canonical extension of AdaBoost to this kind of problems. We additionally suggest a simple procedure to compute cost matrices that improve the performance of Boosting in standard and unbalanced problems. A set of experiments is carried out to demonstrate the effectiveness of both methods against other relevant Boosting algorithms in their respective areas. In the experiments we resort to benchmark data sets used in the Machine Learning community, firstly for minimizing classification errors and secondly for minimizing costs. In addition, we successfully applied BAdaCost to a segmentation task, a particular problem in presence of imbalanced data. We conclude the thesis justifying the horizon of future improvements encompassed in our framework, due to its applicability and theoretical flexibility.

Optimal Piecewise Linear Function Approximation for GPU-based Applications

Many computer vision and human-computer interaction applications developed in recent years need evaluating complex and continuous mathematical functions as an essential step toward proper operation. However, rigorous evaluation of this kind of functions often implies a very high computational cost, unacceptable in real-time applications. To alleviate this problem, functions are commonly approximated by simpler piecewise-polynomial representations. Following this idea, we propose a novel, efficient, and practical technique to evaluate complex and continuous functions using a nearly optimal design of two types of piecewise linear approximations in the case of a large budget of evaluation subintervals. To this end, we develop a thorough error analysis that yields asymptotically tight bounds to accurately quantify the approximation performance of both representations. It provides an improvement upon previous error estimates and allows the user to control the trade-off between the approximation error and the number of evaluation subintervals. To guarantee real-time operation, the method is suitable for, but not limited to, an efficient implementation in modern Graphics Processing Units (GPUs), where it outperforms previous alternative approaches by exploiting the fixed-function interpolation routines present in their texture units. The proposed technique is a perfect match for any application requiring the evaluation of continuous functions, we have measured in detail its quality and efficiency on several functions, and, in particular, the Gaussian function because it is extensively used in many areas of computer vision and cybernetics, and it is expensive to evaluate.

Cognitive Surveillance Architecture for Scenario Understanding

Uno de los mayores retos para la comunidad científica es conseguir que las máquinas posean en un futuro la capacidad del sistema visual y cognitivo humanos, de forma que, por ejemplo, en entornos de video vigilancia, puedan llegar a proporcionar de manera automática una descripción fiable de lo que está ocurriendo en la escena. En la presente tesis, mediante la propuesta de un marco de trabajo de referencia, se discuten y plantean los pasos necesarios para el desarrollo de sistemas más inteligentes capaces de extraer y analizar, a diferentes niveles de abstracción y mediante distintos módulos de procesamiento independientes, la información necesaria para comprender qué está sucediendo en un conjunto amplio de escenarios de distinta naturaleza. Se parte de un análisis de requisitos y se identifican los retos para este tipo de sistemas en la actualidad, lo que constituye en sí mismo los objetivos de esta tesis, contribuyendo así a un modelo de datos basado en el conocimiento que permitirá analizar distintas situaciones en las que personas y vehículos son los actores principales, dejando no obstante la puerta abierta a la adaptación a otros dominios. Así mismo, se estudian los distintos procesos que se pueden lanzar a nivel interno así como la necesidad de integrar mecanismos de realimentación a distintos niveles que permitan al sistema adaptarse mejor a cambios en el entorno. Como resultado, se propone un marco de referencia jerárquico que integra las capacidades de percepción, interpretación y aprendizaje para superar los retos identificados en este ámbito; y así poder desarrollar sistemas de vigilancia más robustos, flexibles e inteligentes, capaces de operar en una variedad de entornos. Resultados experimentales ejecutados sobre distintas muestras de datos (secuencias de vídeo principalmente) demuestran la efectividad del marco de trabajo propuesto respecto a otros propuestos en el pasado. Un primer caso de estudio, permite demostrar la creación de un sistema de monitorización de entornos de parking en exteriores para la detección de vehículos y el análisis de plazas libres de aparcamiento. Un segundo caso de estudio, permite demostrar la flexibilidad del marco de referencia propuesto para adaptarse a los requisitos de un entorno de vigilancia completamente distinto, como es un hogar inteligente donde el análisis automático de actividades de la vida cotidiana centra la atención del estudio. ABSTRACT One of the most ambitious objectives for the Computer Vision and Pattern Recognition research community is that machines can achieve similar capacities to the human's visual and cognitive system, and thus provide a trustworthy description of what is happening in the scene under surveillance. Thus, a number of well-established scenario understanding architectural frameworks to develop applications working on a variety of environments can be found in the literature. In this Thesis, a highly descriptive methodology for the development of scene understanding applications is presented. It consists of a set of formal guidelines to let machines extract and analyse, at different levels of abstraction and by means of independent processing modules that interact with each other, the necessary information to understand a broad set of different real World surveillance scenarios. Taking into account the challenges that working at both low and high levels offer, we contribute with a highly descriptive knowledge-based data model for the analysis of different situations in which people and vehicles are the main actors, leaving the door open for the development of interesting applications in diverse smart domains. Recommendations to let systems achieve high-level behaviour understanding will be also provided. Furthermore, feedback mechanisms are proposed to be integrated in order to let any system to understand better the environment and the logical context around, reducing thus the uncertainty and noise, and increasing its robustness and precision in front of low-level or high-level errors. As a result, a hierarchical cognitive architecture of reference which integrates the necessary perception, interpretation, attention and learning capabilities to overcome main challenges identified in this area of research is proposed; thus allowing to develop more robust, flexible and smart surveillance systems to cope with the different requirements of a variety of environments. Once crucial issues that should be treated explicitly in the design of this kind of systems have been formulated and discussed, experimental results shows the effectiveness of the proposed framework compared with other proposed in the past. Two case studies were implemented to test the capabilities of the framework. The first case study presents how the proposed framework can be used to create intelligent parking monitoring systems. The second case study demonstrates the flexibility of the system to cope with the requirements of a completely different environment, a smart home where activities of daily living are performed. Finally, general conclusions and future work lines to further enhancing the capabilities of the proposed framework are presented.

Sistema colaborativo de detección y seguimiento de anomalías mediante visión por computador

En este proyecto se realiza el diseño e implementación de un sistema que detecta anomalías en las entradas de entornos controlados. Para ello, se hace uso de las últimas técnicas en visión por computador y se avisa visual y auditivamente, mediante un sistema hardware que recibe señales del ordenador al que está conectado. Se marca y fotografía, a una o varias personas, que cometen una infracción en las entradas de un establecimiento, vigilado con sistemas de vídeo. Las imágenes se almacenan en las carpetas correspondientes. El sistema diseñado es colaborativo, por lo tanto, las cámaras que intervienen, se comunican entre ellas a través de estructuras de datos con el objetivo de intercambiar información. Además, se utiliza conexión inalámbrica desde un dispositivo móvil para obtener una visión global del entorno desde cualquier lugar del mundo. La aplicación se desarrolla en el entorno MATLAB, que permite un tratamiento de la señal de imagen apropiado para el presente proyecto. Asimismo, se proporciona al usuario una interfaz gráfica con la que interactuar de manera sencilla, evitando así, el cambio de parámetros en la estructura interna del programa cuando se quiere variar el entorno o el tipo de adquisición de datos. El lenguaje que se escoge facilita la ejecución en distintos sistemas operativos, incluyendo Windows o iOS y, de esta manera, se proporciona flexibilidad. ABSTRACT. This project studies the design and implementation of a system that detects any anomalies on the entrances to controlled environments. To this end, it is necessary the use of last techniques in computer vision in order to notify visually and aurally, by a hardware system which receives signs from the computer it is connected to. One or more people that commit an infringement while entering into a secured environment, with video systems, are marked and photographed and those images are stored in their belonging file folder. This is a collaborative design system, therefore, every involved camera communicates among themselves through data structures with the purpose of exchanging information. Furthermore, to obtain a global environment vision from any place in the world it uses a mobile wireless connection. The application is developed in MATLAB environment because it allows an appropriate treatment of the image signal for this project. In addition, the user is given a graphical interface to easily interact, avoiding with this, changing any parameters on the program’s intern structure, when it requires modifying the environment or the data type acquisition. The chosen language eases its execution in different operating systems, including Windows or iOS, providing flexibility.

Network convergence and QoS for future multimedia services in the VISION project

The emerging use of real-time 3D-based multimedia applications imposes strict quality of service (QoS) requirements on both access and core networks. These requirements and their impact to provide end-to-end 3D videoconferencing services have been studied within the Spanish-funded VISION project, where different scenarios were implemented showing an agile stereoscopic video call that might be offered to the general public in the near future. In view of the requirements, we designed an integrated access and core converged network architecture which provides the requested QoS to end-to-end IP sessions. Novel functional blocks are proposed to control core optical networks, the functionality of the standard ones is redefined, and the signaling improved to better meet the requirements of future multimedia services. An experimental test-bed to assess the feasibility of the solution was also deployed. In such test-bed, set-up and release of end-to-end sessions meeting specific QoS requirements are shown and the impact of QoS degradation in terms of the user perceived quality degradation is quantified. In addition, scalability results show that the proposed signaling architecture is able to cope with large number of requests introducing almost negligible delay.

Remarks on Compositionality (with reference to Gennadij Zeldoviè's article “On Russian Dative Reflexive Constructions: Accidental or Compositional”)

Zeldovič’s article “On Russian Dative Reflexive Constructions: Accidental or Compositional” is very interesting. It contains a good deal of insightful observations and is painstakingly argued. Its research object is the Russian dative reflexive construction (DRC) like Ивану не работается ‘Ivan does not feel like reading’. The aim of the article is to show that the DRC is fully compositional. Like many other works by Zeldovič, the article is written from the radical-pragmatic perspective and constitutes a very good illustration of this trend in linguistic research. The language material that it analyzes has often been investigated within more traditional frameworks, especially in Russian linguistics, which makes Zeldovič’s novel approach to the old problem particularly interesting. In this short note I would like (by way of discussion) to address two problems connected not so much with the DRC itself as with methodological issues concerning compositionality. I will dwell on two aspects: on the question of how we understand the very concept of compositionality, and what instruments we employ to demonstrate it.

Near infrared high efficiency InAs/GaAsSb QDLEDs: band alignment and carrier recombination mechanisms

The development of high efficiency laser diodes (LD) and light emitting diodes (LED) covering the 1.0 to 1.55 μm region of the spectra using GaAs heteroepitaxy has been long pursued. Due to the lack of materials that can be grown lattice-macthed to GaAs with bandgaps in the 1.0 to 1.55 μm region, quantum wells (QW) or quantum dots (QD) need be used. The most successful approach with QWs has been to use InGaAs, but one needs to add another element, such as N, to be able to reach 1.3/1.5μm. Even though LDs have been successfully demonstrated with the QW approach, using N leads to problems with compositional homogeneity across the wafer, and limited efficiency due to strong non-radiative recombination. The alternative approach of using InAs QDs is an attractive option, but once again, to reach the longest wavelengths one needs very large QDs and control over the size distribution and band alignment. In this work we demonstrate InAs/GaAsSb QDLEDs with high efficiencies, emitting from 1.1 to 1.52 μm, and we analyze the band alignment and carrier loss mechanisms that result from the presence of Sb in the capping layer.

Diseño y fabricación de dispositivos basados en cristal líquido polimérico

Esta tesis se centra en el estudio y desarrollo de dispositivos de aplicación basados en cristal líquido polimérico. Las propiedades de los cristales líquidos los hacen interesantes para su uso en el desarrollo de dispositivos de seguridad para autenticación de productos y marcas, y detección y prevención de falsificaciones. Asimismo, pueden ser muy útiles para fabricar dispositivos basados en CLs dispersos en polímero, los cuales tienen a su vez múltiples aplicaciones. La orientación de las moléculas de cristal líquido y la birrefringencia son las dos características principales que afectan a las propiedades de estos dispositivos. Un dispositivo de cristal líquido estándar consiste en un sándwich formado por dos sustratos de vidrio transparente, dotados con electrodo de ITO (Indium Tin Oxide) en su superficie interna, que confinan el cristal líquido en su interior. En la primera parte de esta tesis se describen las características más importantes que describen una célula de cristal líquido. Esta introducción básica en necesaria para la correcta comprensión de los capítulos posteriores en los que se detalla el desarrollo concreto de los dispositivos desarrollados en la investigación llevada a cabo. Por ejemplo, en el caso de los dispositivos de seguridad se han eliminado los sustratos de vidrio (en la última fase de su desarrollo) para conseguir dispositivos flexibles. En la segunda parte de la tesis se incluye la descripción completa de los dispositivos fabricados, así como de los protocolos de fabricación seguidos y diseñados específicamente para ello. También se detallan en esta parte los resultados obtenidos, así como las propiedades ópticas y electroópticas en cada caso, y el/los equipos de caracterización utilizados. Utilizando cristal líquido nemático y colorante dicroico, se han desarrollado dispositivos que contienen múltiples imágenes latentes en cada cara del mismo. Utilizando distintas técnicas de alineamiento se consigue crear cualquier tipo de motivo latente, ya sean símbolos sencillos, figuras, logotipos o incluso imágenes con escala de gris. Cuanto más complejo es el dispositivo, mayor es la dificultad para reproducirlo en una eventual falsificación. Para visualizar e identificar los motivos es necesario emplear luz polarizada, por ejemplo, con la ayuda de un sencillo polarizador lineal. Dependiendo de si el polarizador está colocado delante del dispositivo o detrás del él, se mostrarán las imágenes generadas en una u otra cara. Este efecto es posible gracias al colorante dicroico añadido al CL, a la orientación inducida sobre las moléculas, y a la estructura de twist utilizada en los dispositivos. En realidad, para ver el efecto de los dispositivos no es necesario el uso de un polarizador, basta con el reflejo de una superficie dielétrica (percialmente polarizado), o la luz emitida por la pantalla de dispositivos de consumo comunes como un televisor LCD, un monitor de ordenador o un “smartphone”. Por otro lado, utilizando una mezcla entre un CL nemático polimérico y un CL nemático no polimérico es posible fabricar dispositivos LCPC (Liquid Crystal Polymer Composite) con propiedades electroópticas muy interesantes, que funcionan a tensiones de conmutación bajas. El CL polimérico conforma una estructura de red en el interior del sándwich que mantiene confinado al CL nemático en pequeños microdominios. Se han fabricado dispositivos LCPC con conmutación inversa utilizando tanto alineamiento homogéneo como homeotrópico. Debido a que tanto la estructura de CL polimérico como el CL nemático que rellena los microdominios están orientados en una misma dirección de alineamiento preinducida, la luz dispersada por el dispositivo se encuentra polarizada. La dirección de polarización coincide con la dirección de alineamiento. La innovación aportada por esta investigación: un nuevo dispositivo LCPC inverso de respuesta ultrarápida y polarizada basado en la mezcla de dos CL nemáticos y, un dispositivo de seguridad y autenticación, patentado internacionalmente, basado en CL nemáticos dopados con colorante dicroico. Abstract This thesis is centered on the availability to use polymerizable liquid crystals to develop non-display application LC devices. Liquid crystal properties make them useful for the development of security devices in applications of authentication and detection of fakes, and also to achieve polymer dispersed LC devices to be used for different applications that will be studied here. Induced orientation of liquid crystal molecules and birefringence are the two main properties used in these devices. A standard liquid crystal device is a sandwich consisting of two parallel glass substrates carrying a thin transparent ITO (Indium‐Tin‐Oxide) electrode on their inner surfaces with the liquid crystal in the middle. The first part of this thesis will describe the most important parameters describing a liquid crystal cell. This basis is necessary for the understanding of later chapters where models of the liquid crystal devices will be discussed and developed. In the case of security devices the standard structure of an LC device has been modified by eliminating the glass substrates in order to achieve plastic and flexible devices. The second part of the thesis includes a detailed description of the devices achieved and the manufacturing protocols that have been developed ad-hoc. The optical and electrooptical properties and the characterization equipment are described here as well. Employing nematic liquid crystal and dichroic colorants, we have developed devices that show, with the aid of a polarizer, multiple images on each side of the device. By different alignment techniques it is possible to create any kind of symbols, drawings or motifs with a grayscale; the more complex the created device is, the more difficult is to fake it. To identify the motifs it is necessary to use polarized light. Depending on whether the polarizer is located in front of the LC cell or behind it, different motifs from one or the other substrate are shown. The effect arises from the dopant color dye added to the liquid crystal, the induced orientation and the twist structure. In practice, a grazing reflection on a dielectric surface is polarized enough to see the effect. Any LC flat panel display (LCD TV, computer, mobile phone) can obviously be used as backlight as well. On the other hand, by using a mixture of polymerizable and non-polymerizable nematics liquid crystals it is also possible to achieve LCPC (Liquid Crystal Polymer Composite) devices that show really interesting electrooptical characteristics using low switching voltages. Polymerizable LC creates a hollow structure inside the sandwich glass cell that keep nematics liquid crystal confined creating microdomains. Homogeneous and homeotropic alignments have been used to develop inverse switching mode LCPCs. Due to the double LC oriented structure, the outgoing scattered light from these devices is already polarized. The polarization axis coincides with LC molecules director, the alignment direction promoted. The novelties derived from the investigation presented here, new ultrafast inverse LCPC with polarized outgoing scattered light based on oriented nematic LC mixture, and an internationally patented security and authentication device based on nematics (doped with dichroic dye) oriented polymerizable LC.

Proyectando entre ruinas : lógicas de intervención continua en la arquitectura contemporánea

Los cambios percibidos hacia finales del siglo XX y a principios del nuevo milenio, nos ha mostrado que la crisis cultural de la que somos participes refleja también una crisis de los modelos universales. Nuestra situación contemporánea, parece indicar que ya no es posible formular un sistema estético para atribuirle una vigencia universal e intemporal más allá de su estricta eficacia puntual. La referencia organizada, delimitada, invariable y específica que ofrecía cualquier emplazamiento, en tanto preexistencia, reflejaba una jerarquía del sistema formal basado en lo extensivo: la medida, las normas, el movimiento, el tiempo, la modulación, los códigos y las reglas. Sin embargo, actualmente, algunos aspectos que permanecían latentes sobre lo construido, emergen bajo connotaciones intensivas, transgrediendo la simple manifestación visual y expresiva, para centrase en las propiedades del comportamiento de la materia y la energía como determinantes de un proceso de adaptación en el entorno. A lo largo del todo el siglo XX, el desarrollo de la relación del proyecto sobre lo construido ha sido abordado, casi en exclusiva, entre acciones de preservación o intervención. Ambas perspectivas, manifestaban esfuerzos por articular un pensamiento que diera una consistencia teórica, como soporte para la producción de la acción aditiva. No obstante, en las últimas décadas de finales de siglo, la teoría arquitectónica terminó por incluir pensamientos de otros campos que parecen contaminar la visión sesgada que nos refería lo construido. Todo este entramado conceptual previo, aglomeraba valiosos intentos por dar contenido a una teoría que pudiese ser entendida desde una sola posición argumental. Es así, que en 1979 Ignasi Solá-Morales integró todas las imprecisiones que referían una actuación sobre una arquitectura existente, bajo el termino de “intervención”, el cual fue argumentado en dos sentidos: El primero referido a cualquier tipo de actuación que se puede hacer en un edificio, desde la defensa, preservación, conservación, reutilización, y demás acciones. Se trata de un ámbito donde permanece latente el sentido de intensidad, como factor común de entendimiento de una misma acción. En segundo lugar, más restringido, la idea de intervención se erige como el acto crítico a las ideas anteriores. Ambos representan en definitiva, formas de interpretación de un nuevo discurso. “Una intervención, es tanto como intentar que el edificio vuelva a decir algo o lo diga en una determinada dirección”. A mediados de 1985, motivado por la corriente de revisión historiográfica y la preocupación del deterioro de los centros históricos que recorría toda Europa, Solá-Morales se propone reflexionar sobre “la relación” entre una intervención de nueva arquitectura y la arquitectura previamente existente. Relación condicionada estrictamente bajo consideraciones lingüísticas, a su entender, en sintonía con toda la producción arquitectónica de todo el siglo XX. Del Contraste a la Analogía, resumirá las transformaciones en la concepción discursiva de la intervención arquitectónica, como un fenómeno cambiante en función de los valores culturales, pero a su vez, mostrando una clara tendencia dialógica entres dos categorías formales: El Contraste, enfatizando las posibilidades de la novedad y la diferencia; y por otro lado la emergente Analogía, como una nueva sensibilidad de interpretación del edificio antiguo, donde la semejanza y la diversidad se manifiestan simultáneamente. El aporte reflexivo de los escritos de Solá-Morales podría ser definitivo, si en las últimas décadas antes del fin de siglo, no se hubiesen percibido ciertos cambios sobre la continuidad de la expresión lingüística que fomentaba la arquitectura, hacia una especie de hipertrofia figurativa. Entre muchos argumentos: La disolución de la consistencia compositiva y el estilo unitario, la incorporación volumétrica del proyecto como dispositivo reactivo, y el cambio de visión desde lo retrospectivo hacia lo prospectivo que sugiere la nueva conservación. En este contexto de desintegración, el proyecto, en tanto incorporación o añadido sobre un edificio construido, deja de ser considerado como un apéndice volumétrico subordinado por la reglas compositivas y formales de lo antiguo, para ser considerado como un organismo de orden reactivo, que produce en el soporte existente una alteración en su conformación estructural y sistémica. La extensión, antes espacial, se considera ahora una extensión sensorial y morfológica con la implementación de la tecnología y la hiper-información, pero a su vez, marcados por una fuerte tendencia de optimización energética en su rol operativo, ante el surgimiento del factor ecológico en la producción contemporánea. En una sociedad, como la nuestra, que se está modernizando intensamente, es difícil compartir una adecuada sintonía con las formas del pasado. Desde 1790, fecha de la primera convención francesa para la conservación de monumentos, la escala de lo que se pretende preservar es cada vez más ambiciosa, tanto es así, que al día de hoy el repertorio de lo que se conserva incluye prácticamente todas las tipologías del entorno construido. Para Koolhaas, el intervalo entre el objeto y el momento en el cual se decide su conservación se ha reducido, desde dos milenios en 1882 a unas décadas hoy en día. En breve este lapso desaparecerá, demostrando un cambio radical desde lo retrospectivo hacia lo prospectivo, es decir, que dentro de poco habrá que decidir que es lo que se conserva antes de construir. Solá-Morales, en su momento, distinguió la relación entre lo nuevo y lo antiguo, entre el contraste y la analogía. Hoy casi tres décadas después, el objetivo consiste en evaluar si el modelo de intervención arquitectónica sobre lo construido se ha mantenido desde entonces o si han aparecido nuevas formas de posicionamiento del proyecto sobre lo construido. Nuestro trabajo pretende demostrar el cambio de enfoque proyectual con la preexistencia y que éste tiene estrecha relación con la incorporación de nuevos conceptos, técnicas, herramientas y necesidades que imprimen el contexto cultural, producido por el cambio de siglo. Esta suposición nos orienta a establecer un paralelismo arquitectónico entre los modos de relación en que se manifiesta lo nuevo, entre una posición comúnmente asumida (Tópica), genérica y ortodoxa, fundamentada en lo visual y expresivo de las últimas décadas del siglo XX, y una realidad emergente (Heterotópica), extraordinaria y heterodoxa que estimula lo inmaterial y que parece emerger con creciente intensidad en el siglo XXI. Si a lo largo de todo el siglo XX, el proyecto de intervención arquitectónico, se debatía entre la continuidad y discontinuidad de las categorías formales marcadas por la expresión del edificio preexistente, la nueva intervención contemporánea, como dispositivo reactivo en el paisaje y en el territorio, demanda una absoluta continuidad, ya no visual, expresiva, ni funcional, sino una continuidad fisiológica de adaptación y cambio con la propia dinámica del territorio, bajo nuevas reglas de juego y desplegando planes y estrategias operativas (proyectivas) desde su propia lógica y contingencia. El objeto de esta investigación es determinar los nuevos modos de continuidad y las posibles lógicas de producción que se manifiestan dentro de la Intervención Arquitectónica, intentando superar lo aparente de su relación física y visual, como resultado de la incorporación del factor operativo desplegado por el nuevo dispositivo contemporáneo. Creemos que es acertado mantener la senda connotativa que marca la denominación intervención arquitectónica, por aglutinar conceptos y acercamientos teóricos previos que han ido evolucionando en el tiempo. Si bien el término adolece de mayor alcance operativo desde su formulación, una cualidad que infieren nuestras lógicas contemporáneas, podría ser la reformulación y consolidación de un concepto de intervención más idóneo con nuestros tiempos, anteponiendo un procedimiento lógico desde su propia necesidad y contingencia. Finalmente, nuestro planteamiento inicial aspira a constituir un nueva forma de reflexión que nos permita comprender las complejas implicaciones que infiere la nueva arquitectura sobre la preexistencia, motivada por las incorporación de factores externos al simple juicio formal y expresivo preponderante a finales del siglo XX. Del mismo modo, nuestro camino propuesto, como alternativa, permite proyectar posibles sendas de prospección, al considerar lo preexistente como un ámbito que abarca la totalidad del territorio con dinámicas emergentes de cambio, y con ellas, sus lógicas de intervención.Abstract The perceived changes towards the end of the XXth century and at the beginning of the new milennium have shown us that the cultural crisis in which we participate also reflects a crisis of the universal models. The difference between our contemporary situation and the typical situations of modern orthodoxy and post-modernistic fragmentation, seems to indicate that it is no longer possible to formulate a valid esthetic system, to assign a universal and eternal validity to it beyond its strictly punctual effectiveness; which is even subject to questioning because of the continuous transformations that take place in time and in the sensibility of the subject itself every time it takes over the place. The organised reference that any location offered, limited, invariable and specific, while pre-existing, reflected a hierarchy of the formal system based on the applicable: measure, standards, movement, time, modulation, codes and rules. Authors like Marshall Mc Luhan, Paul Virilio, or Marc Augé anticipated a reality where the conventional system already did not seem to respond to the new architectural requests in which information, speed, disappearance and the virtual had blurred the traditional limits of place; pre-existence did no longer possess a specific delimitation and, on the contrary, they expect to reach a global scale. Currently, some aspects that stayed latent relating to the constructed, surface from intensive connotations, transgressing the simple visual and expressive manifestation in order to focus on the traits of the behaviour of material and energy as determinants of a process of adaptation to the surroundings. Throughout the entire Century, the development of the relation of the project relating to the constructed has been addressed, almost exclusively, in preservational or interventianal actions. Both perspectives showed efforts in order to express a thought that would give a theoretical consistency as a base for the production of the additive action. Nevertheless, the last decades of the Century, architectural theory ended up including thoughts from other fields that seem to contaminate the biased vision 15 which the constructed related us. Ecology, planning, philosophy, global economy, etc, suggest new approaches to the construction of the contemporary city; but this time with a determined idea of change and continuous transformation, that enriches the panorama of thought and architectural practice, at the same time, according to some, it puts disciplinary specification at risk, given that there is no architecture without destruction, the constructed organism requires mutation in order to adjust to the change of shape. All of this previous conceptual framework gathered valuable intents to give importance to a theory that could be understood solely from an argumental position. Thusly, in 1979 Ignasi Solá-Morales integrated all of the imprecisions that referred to an action in existing architecture under the term of “Intervention”, which was explained in two ways: The first referring to any type of intervention that can be carried out in a building, regarding protection, conservation, reuse, etc. It is about a scope where the meaning of intensity stays latent as a common factor of the understanding of a single action. Secondly, more limitedly, the idea of intervention is established as the critical act to the other previous ideas such as restauration, conservation, reuse, etc. Both ultimately represent ways of interpretation of a new speech. “An intervention, is as much as trying to make the building say something again or that it be said in a certain direction”. Mid 1985, motivated by the current of historiographical revision and the concerns regarding the deterioration of historical centres that traversed Europe, Solá-Morales decides to reflect on “the relationship” between an intervention of the new architecture and the previously existing architecture. A relationship determined strictly by linguistic considerations, to his understanding, in harmony with all of the architectural production of the XXth century. From Contrast to Analogy would summarise transformations in the discursive perception of architectural intervention, as a changing phenomenon depending on cultural values, but at the same time, showing a clear dialogical tendency between two formal categories: Contrast, emphasising the possibilities of novelty and difference; and on the other hand the emerging Analogy, as a new awareness of interpretation of the ancient building, where the similarity and diversity are manifested simultaneously. For Solá-Morales the analogical procedure is not based on the visible simultaneity of formal orders, but on associations that the subject establishes throughout time. Through analogy it is tried to overcome the simple visual relationship with the antique, to focus on its spacial, physical and geographical nature. If the analogical attempt guides an opening towards a new continuity; it still persists in the connection of dimensional, typological and figurative factors, subordinate to the formal hierarchy of the preexisting subjects. 16 The reflexive contribution of Solá-Morales’ works could be final, if in the last decades before the end of the century there had not been certain changes regarding linguistic expression, encouraged by architecture, towards a kind of figurative hypertrophy, amongst many arguments we are in this case interested in three moments: The dissolution of the compositional consistency and the united style, the volumetric incorporation of the project as a reactive mechanism, and the change of the vision from retrospective towards prospective that the new conservation suggests. The recurrence to the history of architecture and its recognisable forms, as a way of perpetuating memory and establishing a reference, dissolved any instinct of compositive unity and style, provoking permanent relationships to tend to disappear. The composition and coherence lead to suppose a type of discontinuity of isolated objects in which only possible relationships could appear; no longer as an order of certain formal and compositive rules, but as a special way of setting elements in a specific work. The new globalised field required new forms of consistency between the project and the pre-existent subject, motivated amongst others by the higher pace of market evolution, increase of consumer tax and the level of information and competence between different locations; aspects which finally made stylistic consistence inefficient. In this context of disintegration, the project, in incorporation as well as added to a constructed building, stops being considered as a volumetric appendix subordinate to compositive and formal rules of old, to be considered as an organism of reactive order, that causes a change in the structural and systematic configuration of the existing foundation. The extension, previsouly spatial, is now considered a sensorial and morphological extension, with the implementation of technology and hyper-information, but at the same time, marked by a strong tendency of energetic optimization in its operational role, facing the emergence of the ecological factor in contemporary production. The technological world turns into a new nature, a nature that should be analysed from ecological terms; in other words, as an event of transition in the continuous redistribution of energy. In this area, effectiveness is not only determined by the capacity of adaptation to changing conditions, but also by its transforming capacity “expressly” in order to change an environment. In a society, like ours, that is modernising intensively, it is difficult to share an adecuate agreement with the forms of the past. From 1790, the date of the first French convention for the conservation of monuments, the scale of what is expexted to be preserved is more and more ambitious, so much so that nowadays the repertoire of that what is conserved includes practically all typologies of the constructed surroundings. For Koolhaas, the ínterval between the object and the moment when its conservation is decided has been reduced, from two 17 milennia in 1882 to a few decades nowadays. Shortly this lapse will disappear, showing a radical change of retrospective towards prospective, that is to say, that soon it will be necessary to decide what to conserve before constructing. The shapes of cities are the result of the continuous incorporation of architecture, and perhaps that only through architecture the response to the universe can be understood, the continuity of what has already been constructed. Our work is understood also within that system, modifying the field of action and leaving the road ready for the next movement of those that will follow after us. Continuity does not mean conservatism, continuity means being conscient of the transitory value of our answers to specific needs, accepting the change that we have received. That what has been constructed to remain and last, should cause future interventions to be integrated in it. It is necessary to accept continuity as a rule. Solá-Morales, in his time, distinguished between the relationship with new and old, between contrast and analogy. Today, almost three decades later, the objective consists of evaluating whether the model of architectural intervention in the constructed has been maintained since then or if new ways of positioning the project regarding the constructed have appeared. Our work claims to show the change of the approach of projects with pre-existing subjects and that this has got a close relation to the incorporation of new concepts, techniques, tools and necessities that impress the cultural context, caused by the change of centuries. This assumption guides us to establish a parallelism between the forms of connection where that what is new is manifested between a commonly assumed (topical), generic and orthodox position, based on that what is visual and expressive in the last decades of the XXth century, and an emerging (heterotopical), extraordinary and heterodox reality that stimulates the immaterial and that seems to emerge with growing intensity in the XXIst century. If throughout the XXth century the project of architectural intervention was considered from the continuity and discontinuity of formal categories, marked by the expression of the pre-existing building, the new contemporary intervention, as a reactive device in the landscape and territory, demands an absolute continuity. No longer a visual, expressive or functional one but a morphological continuity of adaptation and change with its own territorial dynamics, under new game rules and unfolding new operative (projective) strategies from its own logic and contingency. 18 The aim of this research is to determine new forms of continuity and the possible logic of production that are expressed in the Architectural Intervention, trying to overcome the obviousness of its physical and visual relationship, at the beginning of this new century, as a result of the incorporation of the operative factor that the new architectural device unfolds. We think it is correct to maintain the connotative path that marks the name architectural intervention by bringing previous concepts and theorical approaches that have been evolving through time together. If the name suffers from a wider operational range because of its formulation, a quality that our contemporary logic provokes, the reformulation and consolidation of an interventional concept could be more suitable for our times, giving preference to a logical method from its own necessity and contingency. It seems that now time shapes the topics, it is no longer about materialising a certain time but about expressing the changes that its new temporality generates. Finally, our initial approach aspires to form a new way of reflection that permits us to understand the complex implications that the new architecture submits the pre-existing subject to, motivated by the incorporation of factors external to simple formal and expressive judgement, prevailing at the end of the XXth century. In the same way, our set road, as an alternative, permits the contemplation of possible research paths, considering that what is pre-existing as an area that spans the whole territory with emerging changing dynamics and, with them, their interventional logics.

A guided heuristic approach to the MEG inverse problem.

There is general agreement within the scientific community in considering Biology as the science with more potential to develop in the XXI century. This is due to several reasons, but probably the most important one is the state of development of the rest of experimental and technological sciences. In this context, there are a very rich variety of mathematical tools, physical techniques and computer resources that permit to do biological experiments that were unbelievable only a few years ago. Biology is nowadays taking advantage of all these newly developed technologies, which are been applied to life sciences opening new research fields and helping to give new insights in many biological problems. Consequently, biologists have improved a lot their knowledge in many key areas as human function and human diseases. However there is one human organ that is still barely understood compared with the rest: The human brain. The understanding of the human brain is one of the main challenges of the XXI century. In this regard, it is considered a strategic research field for the European Union and the USA. Thus, there is a big interest in applying new experimental techniques for the study of brain function. Magnetoencephalography (MEG) is one of these novel techniques that are currently applied for mapping the brain activity1. This technique has important advantages compared to the metabolic-based brain imagining techniques like Functional Magneto Resonance Imaging2 (fMRI). The main advantage is that MEG has a higher time resolution than fMRI. Another benefit of MEG is that it is a patient friendly clinical technique. The measure is performed with a wireless set up and the patient is not exposed to any radiation. Although MEG is widely applied in clinical studies, there are still open issues regarding data analysis. The present work deals with the solution of the inverse problem in MEG, which is the most controversial and uncertain part of the analysis process3. This question is addressed using several variations of a new solving algorithm based in a heuristic method. The performance of those methods is analyzed by applying them to several test cases with known solutions and comparing those solutions with the ones provided by our methods.

Generación de Casos de Prueba en Programación Orientada a Objetos = Test Case Generation in Object-Oriented Programming

Las pruebas de software (Testing) son en la actualidad la técnica más utilizada para la validación y la evaluación de la calidad de un programa. El testing está integrado en todas las metodologías prácticas de desarrollo de software y juega un papel crucial en el éxito de cualquier proyecto de software. Desde las unidades de código más pequeñas a los componentes más complejos, su integración en un sistema de software y su despliegue a producción, todas las piezas de un producto de software deben ser probadas a fondo antes de que el producto de software pueda ser liberado a un entorno de producción. La mayor limitación del testing de software es que continúa siendo un conjunto de tareas manuales, representando una buena parte del coste total de desarrollo. En este escenario, la automatización resulta fundamental para aliviar estos altos costes. La generación automática de casos de pruebas (TCG, del inglés test case generation) es el proceso de generar automáticamente casos de prueba que logren un alto recubrimiento del programa. Entre la gran variedad de enfoques hacia la TCG, esta tesis se centra en un enfoque estructural de caja blanca, y más concretamente en una de las técnicas más utilizadas actualmente, la ejecución simbólica. En ejecución simbólica, el programa bajo pruebas es ejecutado con expresiones simbólicas como argumentos de entrada en lugar de valores concretos. Esta tesis se basa en un marco general para la generación automática de casos de prueba dirigido a programas imperativos orientados a objetos (Java, por ejemplo) y basado en programación lógica con restricciones (CLP, del inglés constraint logic programming). En este marco general, el programa imperativo bajo pruebas es primeramente traducido a un programa CLP equivalente, y luego dicho programa CLP es ejecutado simbólicamente utilizando los mecanismos de evaluación estándar de CLP, extendidos con operaciones especiales para el tratamiento de estructuras de datos dinámicas. Mejorar la escalabilidad y la eficiencia de la ejecución simbólica constituye un reto muy importante. Es bien sabido que la ejecución simbólica resulta impracticable debido al gran número de caminos de ejecución que deben ser explorados y a tamaño de las restricciones que se deben manipular. Además, la generación de casos de prueba mediante ejecución simbólica tiende a producir un número innecesariamente grande de casos de prueba cuando es aplicada a programas de tamaño medio o grande. Las contribuciones de esta tesis pueden ser resumidas como sigue. (1) Se desarrolla un enfoque composicional basado en CLP para la generación de casos de prueba, el cual busca aliviar el problema de la explosión de caminos interprocedimiento analizando de forma separada cada componente (p.ej. método) del programa bajo pruebas, almacenando los resultados y reutilizándolos incrementalmente hasta obtener resultados para el programa completo. También se ha desarrollado un enfoque composicional basado en especialización de programas (evaluación parcial) para la herramienta de ejecución simbólica Symbolic PathFinder (SPF). (2) Se propone una metodología para usar información del consumo de recursos del programa bajo pruebas para guiar la ejecución simbólica hacia aquellas partes del programa que satisfacen una determinada política de recursos, evitando la exploración de aquellas partes del programa que violan dicha política. (3) Se propone una metodología genérica para guiar la ejecución simbólica hacia las partes más interesantes del programa, la cual utiliza abstracciones como generadores de trazas para guiar la ejecución de acuerdo a criterios de selección estructurales. (4) Se propone un nuevo resolutor de restricciones, el cual maneja eficientemente restricciones sobre el uso de la memoria dinámica global (heap) durante ejecución simbólica, el cual mejora considerablemente el rendimiento de la técnica estándar utilizada para este propósito, la \lazy initialization". (5) Todas las técnicas propuestas han sido implementadas en el sistema PET (el enfoque composicional ha sido también implementado en la herramienta SPF). Mediante evaluación experimental se ha confirmado que todas ellas mejoran considerablemente la escalabilidad y eficiencia de la ejecución simbólica y la generación de casos de prueba. ABSTRACT Testing is nowadays the most used technique to validate software and assess its quality. It is integrated into all practical software development methodologies and plays a crucial role towards the success of any software project. From the smallest units of code to the most complex components and their integration into a software system and later deployment; all pieces of a software product must be tested thoroughly before a software product can be released. The main limitation of software testing is that it remains a mostly manual task, representing a large fraction of the total development cost. In this scenario, test automation is paramount to alleviate such high costs. Test case generation (TCG) is the process of automatically generating test inputs that achieve high coverage of the system under test. Among a wide variety of approaches to TCG, this thesis focuses on structural (white-box) TCG, where one of the most successful enabling techniques is symbolic execution. In symbolic execution, the program under test is executed with its input arguments being symbolic expressions rather than concrete values. This thesis relies on a previously developed constraint-based TCG framework for imperative object-oriented programs (e.g., Java), in which the imperative program under test is first translated into an equivalent constraint logic program, and then such translated program is symbolically executed by relying on standard evaluation mechanisms of Constraint Logic Programming (CLP), extended with special treatment for dynamically allocated data structures. Improving the scalability and efficiency of symbolic execution constitutes a major challenge. It is well known that symbolic execution quickly becomes impractical due to the large number of paths that must be explored and the size of the constraints that must be handled. Moreover, symbolic execution-based TCG tends to produce an unnecessarily large number of test cases when applied to medium or large programs. The contributions of this dissertation can be summarized as follows. (1) A compositional approach to CLP-based TCG is developed which overcomes the inter-procedural path explosion by separately analyzing each component (method) in a program under test, stowing the results as method summaries and incrementally reusing them to obtain whole-program results. A similar compositional strategy that relies on program specialization is also developed for the state-of-the-art symbolic execution tool Symbolic PathFinder (SPF). (2) Resource-driven TCG is proposed as a methodology to use resource consumption information to drive symbolic execution towards those parts of the program under test that comply with a user-provided resource policy, avoiding the exploration of those parts of the program that violate such policy. (3) A generic methodology to guide symbolic execution towards the most interesting parts of a program is proposed, which uses abstractions as oracles to steer symbolic execution through those parts of the program under test that interest the programmer/tester most. (4) A new heap-constraint solver is proposed, which efficiently handles heap-related constraints and aliasing of references during symbolic execution and greatly outperforms the state-of-the-art standard technique known as lazy initialization. (5) All techniques above have been implemented in the PET system (and some of them in the SPF tool). Experimental evaluation has confirmed that they considerably help towards a more scalable and efficient symbolic execution and TCG.

An approach to a model of the visual cortex: disorders of vision

One of the most challenging problems that must be solved by any theoretical model purporting to explain the competence of the human brain for relational tasks is the one related with the analysis and representation of the internal structure in an extended spatial layout of múltiple objects. In this way, some of the problems are related with specific aims as how can we extract and represent spatial relationships among objects, how can we represent the movement of a selected object and so on. The main objective of this paper is the study of some plausible brain structures that can provide answers in these problems. Moreover, in order to achieve a more concrete knowledge, our study will be focused on the response of the retinal layers for optical information processing and how this information can be processed in the first cortex layers. The model to be reported is just a first trial and some major additions are needed to complete the whole vision process.

MMonCa: An Object Kinetic Monte Carlo simulator for damage irradiation evolution and defect diffusion

In this work, we introduce the Object Kinetic Monte Carlo (OKMC) simulator MMonCa and simulate the defect evolution in three different materials. We start by explaining the theory of OKMC and showing some details of how such theory is implemented by creating generic structures and algorithms in the objects that we want to simulate. Then we successfully reproduce simulated results for defect evolution in iron, silicon and tungsten using our simulator and compare with available experimental data and similar simulations. The comparisons validate MMonCa showing that it is powerful and flexible enough to be customized and used to study the damage evolution of defects in a wide range of solid materials.