TELMA: Technology enhanced learning environment for minimally invasive surgery

Background: Cognitive skills training for minimally invasive surgery has traditionally relied upon diverse tools, such as seminars or lectures. Web technologies for e-learning have been adopted to provide ubiquitous training and serve as structured repositories for the vast amount of laparoscopic video sources available. However, these technologies fail to offer such features as formative and summative evaluation, guided learning, or collaborative interaction between users. Methodology: The "TELMA" environment is presented as a new technology-enhanced learning platform that increases the user's experience using a four-pillared architecture: (1) an authoring tool for the creation of didactic contents; (2) a learning content and knowledge management system that incorporates a modular and scalable system to capture, catalogue, search, and retrieve multimedia content; (3) an evaluation module that provides learning feedback to users; and (4) a professional network for collaborative learning between users. Face validation of the environment and the authoring tool are presented. Results: Face validation of TELMA reveals the positive perception of surgeons regarding the implementation of TELMA and their willingness to use it as a cognitive skills training tool. Preliminary validation data also reflect the importance of providing an easy-to-use, functional authoring tool to create didactic content. Conclusion: The TELMA environment is currently installed and used at the Jesús Usón Minimally Invasive Surgery Centre and several other Spanish hospitals. Face validation results ascertain the acceptance and usefulness of this new minimally invasive surgery training environment.

The seminar of nuclear safety in advanced reactors and the seminar of nuclear fusion: two formative initiatives from Universidad Politécnica de Madrid and spanish young Generation in Nuclear (Jóvenes Nucleares)

panish Young Generation in Nuclear (Jóvenes Nucleares) is a commission of the Spanish Nuclear Society (SNE), whose main goals are to spread knowledge about nuclear energy among the society. Following this motivation, two Seminars have been carried out with the collaboration of the Technical University of Madrid: The Seminar of Nuclear Safety in Advanced Reactors (SRA) and the Seminar of Nuclear Fusion (SFN). The first one, which has been celebrated every year since 2010, aims to show clearly the advances that have been obtained in the section of safety with the new reactors, from a technical but simple point of view and without needing great previous nuclear engineering knowledge. The second one, which first edition was held in 2011, aims to give a general overview of the past, present and future situation of nuclear fusion technology, and was born as a result of the increasing interest of our Spanish Young Generation members in this technology.

All-optical logic gates with 1550nm Fabry-Perot and distributed feedback semiconductor laser amplifiers

The optical bistability occurring in laser diode amplifiers is used to design an all-optical logic gate capable to provide the whole set of logic functions. The structure of the reported logic gate is based on two connected 1550nm laser amplifiers (Fabry-Perot and distributed feedback laser amplifiers).

Instabilities In hybrid optical bistable devices with nonlinear feedback

As we have shown,several output conditions can be obtained from a hybrid optical bistable device when twisted nematic liquid crystal cells are employed as nonlinear elements.

A Web-based Support System for Providing Effective Monitoring, Feedback and Evaluation in Project Management Education

This work introduces a web-based learning environment to facilitate learning in Project Management. The proposed web-based support system integrates methodological procedures and information systems, allowing to promote learning among geographically-dispersed students. Thus, students who are enrolled in different universities at different locations and attend their own project management courses, share a virtual experience in executing and managing projects. Specific support systems were used or developed to automatically collect information about student activities, making it possible to monitor the progress made on learning and assess learning performance as established in the defined rubric.

Dynamic gamma frequency feedback coupling between higher and lower order visual cortices underlies perceptual completion in humans

To perceive a coherent environment, incomplete or overlapping visual forms must be integrated into meaningful coherent percepts, a process referred to as ?Gestalt? formation or perceptual completion. Increasing evidence suggests that this process engages oscillatory neuronal activity in a distributed neuronal assembly. A separate line of evidence suggests that Gestalt formation requires top-down feedback from higher order brain regions to early visual cortex. Here we combine magnetoencephalography (MEG) and effective connectivity analysis in the frequency domain to specifically address the effective coupling between sources of oscillatory brain activity during Gestalt formation. We demonstrate that perceptual completion of two-tone ?Mooney? faces induces increased gamma frequency band power (55?71 Hz) in human early visual, fusiform and parietal cortices. Within this distributed neuronal assembly fusiform and parietal gamma oscillators are coupled by forward and backward connectivity during Mooney face perception, indicating reciprocal influences of gamma activity between these higher order visual brain regions. Critically, gamma band oscillations in early visual cortex are modulated by top-down feedback connectivity from both fusiform and parietal cortices. Thus, we provide a mechanistic account of Gestalt perception in which gamma oscillations in feature sensitive and spatial attention-relevant brain regions reciprocally drive one another and convey global stimulus aspects to local processing units at low levels of the sensory hierarchy by top-down feedback. Our data therefore support the notion of inverse hierarchical processing within the visual system underlying awareness of coherent percepts.

Noise-induced attractor annihilation in the delayed feedback logistic map

We study dynamics of the bistable logistic map with delayed feedback, under the influence of white Gaussian noise and periodic modulation applied to the variable. This system may serve as a model to describe population dynamics under finite resources in noisy environment with seasonal fluctuations. While a very small amount of noise has no effect on the global structure of the coexisting attractors in phase space, an intermediate noise totally eliminates one of the attractors. Slow periodic modulation enhances the attractor annihilation.

Aprendizaje colaborativo en enseñanza a distancia: entorno genérico para configurar, realizar y analizar actividades en grupo

En esta tesis se ha profundizado en el estudio y desarrollo de modelos de soporte para el aprendizaje colaborativo a distancia, que ha permitido proponer una arquitectura fundamentada en los principios del paradigma CSCL (Computer Supported Collaborative Learning). La arquitectura propuesta aborda un tipo de problema concreto que requiere el uso de técnicas derivadas del Trabajo Colaborativo, la Inteligencia Artificial, Interfaces de Usuario así como ideas tomadas de la Pedagogía y la Psicología. Se ha diseñado una solución completa, abierta y genérica. La arquitectura aprovecha las nuevas tecnologías para lograr un sistema efectivo de apoyo a la educación a distancia. Está organizada en cuatro niveles: el de Configuración, el de Experiencia, el de Organización y el de Análisis. A partir de ella se ha implementado un sistema llamado DEGREE. En DEGREE, cada uno de los niveles de la arquitectura da lugar a un subsistema independiente pero relacionado con los otros. La aplicación saca partido del uso de espacios de trabajo estructurados. El subsistema Configurador de Experiencias permite definir los elementos de un espacio de trabajo y una experiencia y adaptarlos a cada tipo de usuario. El subsistema Manejador de Experiencias recoge las contribuciones de los usuarios para construir una solución conjunta de un problema. Las intervenciones de los alumnos se estructuran basándose en un grafo conversacional genérico. Además, se registran todas las acciones de los usuarios para representar explícitamente el proceso completo que lleva a la solución. Estos datos también se almacenan en una memoria común que constituye el subsistema llamado Memoria Organizativa de Experiencias. El subsistema Analizador estudia las intervenciones de los usuarios. Este análisis permite inferir conclusiones sobre la forma en que trabajan los grupos y sus actitudes frente a la colaboración, teniendo en cuenta además el conocimiento subjetivo del observador. El proceso de desarrollo en paralelo de la arquitectura y el sistema ha seguido un ciclo de refinamiento en cinco fases con sucesivas etapas de prototipado y evaluación formativa. Cada fase de este proceso se ha realizado con usuarios reales y se han considerado las opiniones de los usuarios para mejorar las funcionalidades de la arquitectura así como la interfaz del sistema. Esta aproximación ha permitido, además, comprobar la utilidad práctica y la validez de las propuestas que sustentan este trabajo.---ABSTRACT---In this thesis, we have studied in depth the development of support models for distance collaborative learning and subsequently devised an architecture based on the Computer Supported Collaborative Learning paradigm principles. The proposed architecture addresses a specific problem: coordinating groups of students to perform collaborative distance learning activities. Our approach uses Cooperative Work, Artificial Intelligence and Human-Computer Interaction techniques as well as some ideas from the fields of Pedagogy and Psychology. We have designed a complete, open and generic solution. Our architecture exploits the new information technologies to achieve an effective system for education purposes. It is organised into four levels: Configuration, Experience, Organisation and Reflection. This model has been implemented into a system called DEGREE. In DEGREE, each level of the architecture gives rise to an independent subsystem related to the other ones. The application benefits from the use of shared structured workspaces. The configuration subsystem allows customising the elements that define an experience and a workspace. The experience subsystem gathers the users' contributions to build joint solutions to a given problem. The students' interventions build up a structure based on a generic conversation graph. Moreover, all user actions are registered in order to represent explicitly the complete process for reaching the group solution. Those data are also stored into a common memory, which constitutes the organisation subsystem. The user interventions are studied by the reflection subsystem. This analysis allows us inferring conclusions about the way in which the group works and its attitudes towards collaboration. The inference process takes into account the observer's subjective knowledge. The process of developing both the architecture and the system in parallel has run through a five-pass cycle involving successive stages of prototyping and formative evaluation. At each stage of that process, we have considered the users' feedback for improving the architecture's functionalities as well as the system interface. This approach has allowed us to prove the usability and validity of our proposal.

Peer Assessment and Self-assessment: Effective Learning Tools in Higher Education.

When used appropriately, self- and peer-assessment are very effective learning tools. In the present work, instructor formative assessment and feedback, self-assessment (SA), and peer-assessment (PA) have been compared. During the first part of a semester, the students followed a continuous formative assessment. Subsequently, they were divided into two subgroups based on similar performances. One subgroup performed SAs, and the other followedPAduring the last part of the course. The performances of the two groups in solving problems were compared. Results suggest that PA is a more effective learning tool than SA, and both are more effective than instructor formative assessment. However, a survey that was conducted at the end of the experiment showed higher student confidence in instructor assessment than in PA. The students recognized the usefulness of acting as peer assessors, but believed that SA helped them more than PA.

Emission regimes in a distributed feedback tapered master-oscillator power-amplifier at 1.5 µm

Integrated master-oscillator power amplifiers driven under steady-state injection conditions are known to show a complex dynamics resulting in a variety of emission regimes. We present experimental results on the emission characteristics of a 1.5 µm distributed feedback tapered master-oscillator power-amplifier in a wide range of steady-state injection conditions, showing different dynamic behaviors. The study combines the optical and radio-frequency spectra recorded under different levels of injected current into the master oscillator and the power amplifier sections. Under low injection current of the master oscillator the correlation between the optical and radio-frequency spectral maps allows to identify operation regimes in which the device emission arises from either the master oscillator mode or from the compound cavity modes allowed by the residual reflectance of the amplifier front facet. The quasi-periodic occurrence of these emission regimes as a function of the amplifier current is interpreted in terms of a thermally tuned competition between the modes of the master oscillator and the compound cavity modes. Under high injection current of the masteroscillator, two different regimes alternate quasi-periodically as a function of the injected current in the power amplifier: a stable regime with a single mode emission at the master oscillator frequency, and an unstable and complex self-pulsating regime showing strong peaks in the radio-frequency spectra as well as multiple frequencies in the optical spectra.

Securing implementations of feedback-shift-register-based ciphers using compiler optimizations and co-processors

Los algoritmos basados en registros de desplazamiento con realimentación (en inglés FSR) se han utilizado como generadores de flujos pseudoaleatorios en aplicaciones con recursos limitados como los sistemas de apertura sin llave. Se considera canal primario a aquel que se utiliza para realizar una transmisión de información. La aparición de los ataques de canal auxiliar (en inglés SCA), que explotan información filtrada inintencionadamente a través de canales laterales como el consumo, las emisiones electromagnéticas o el tiempo empleado, supone una grave amenaza para estas aplicaciones, dado que los dispositivos son accesibles por un atacante. El objetivo de esta tesis es proporcionar un conjunto de protecciones que se puedan aplicar de forma automática y que utilicen recursos ya disponibles, evitando un incremento sustancial en los costes y alargando la vida útil de aplicaciones que puedan estar desplegadas. Explotamos el paralelismo existente en algoritmos FSR, ya que sólo hay 1 bit de diferencia entre estados de rondas consecutivas. Realizamos aportaciones en tres niveles: a nivel de sistema, utilizando un coprocesador reconfigurable, a través del compilador y a nivel de bit, aprovechando los recursos disponibles en el procesador. Proponemos un marco de trabajo que nos permite evaluar implementaciones de un algoritmo incluyendo los efectos introducidos por el compilador considerando que el atacante es experto. En el campo de los ataques, hemos propuesto un nuevo ataque diferencial que se adapta mejor a las condiciones de las implementaciones software de FSR, en las que el consumo entre rondas es muy similar. SORU2 es un co-procesador vectorial reconfigurable propuesto para reducir el consumo energético en aplicaciones con paralelismo y basadas en el uso de bucles. Proponemos el uso de SORU2, además, para ejecutar algoritmos basados en FSR de forma segura. Al ser reconfigurable, no supone un sobrecoste en recursos, ya que no está dedicado en exclusiva al algoritmo de cifrado. Proponemos una configuración que ejecuta múltiples algoritmos de cifrado similares de forma simultánea, con distintas implementaciones y claves. A partir de una implementación sin protecciones, que demostramos que es completamente vulnerable ante SCA, obtenemos una implementación segura a los ataques que hemos realizado. A nivel de compilador, proponemos un mecanismo para evaluar los efectos de las secuencias de optimización del compilador sobre una implementación. El número de posibles secuencias de optimizaciones de compilador es extremadamente alto. El marco de trabajo propuesto incluye un algoritmo para la selección de las secuencias de optimización a considerar. Debido a que las optimizaciones del compilador transforman las implementaciones, se pueden generar automáticamente implementaciones diferentes combinamos para incrementar la seguridad ante SCA. Proponemos 2 mecanismos de aplicación de estas contramedidas, que aumentan la seguridad de la implementación original sin poder considerarse seguras. Finalmente hemos propuesto la ejecución paralela a nivel de bit del algoritmo en un procesador. Utilizamos la forma algebraica normal del algoritmo, que automáticamente se paraleliza. La implementación sobre el algoritmo evaluado mejora en rendimiento y evita que se filtre información por una ejecución dependiente de datos. Sin embargo, es más vulnerable ante ataques diferenciales que la implementación original. Proponemos una modificación del algoritmo para obtener una implementación segura, descartando parcialmente ejecuciones del algoritmo, de forma aleatoria. Esta implementación no introduce una sobrecarga en rendimiento comparada con las implementaciones originales. En definitiva, hemos propuesto varios mecanismos originales a distintos niveles para introducir aleatoridad en implementaciones de algoritmos FSR sin incrementar sustancialmente los recursos necesarios. ABSTRACT Feedback Shift Registers (FSR) have been traditionally used to implement pseudorandom sequence generators. These generators are used in Stream ciphers in systems with tight resource constraints, such as Remote Keyless Entry. When communicating electronic devices, the primary channel is the one used to transmit the information. Side-Channel Attack (SCA) use additional information leaking from the actual implementation, including power consumption, electromagnetic emissions or timing information. Side-Channel Attacks (SCA) are a serious threat to FSR-based applications, as an attacker usually has physical access to the devices. The main objective of this Ph.D. thesis is to provide a set of countermeasures that can be applied automatically using the available resources, avoiding a significant cost overhead and extending the useful life of deployed systems. If possible, we propose to take advantage of the inherent parallelism of FSR-based algorithms, as the state of a FSR differs from previous values only in 1-bit. We have contributed in three different levels: architecture (using a reconfigurable co-processor), using compiler optimizations, and at bit level, making the most of the resources available at the processor. We have developed a framework to evaluate implementations of an algorithm including the effects introduced by the compiler. We consider the presence of an expert attacker with great knowledge on the application and the device. Regarding SCA, we have presented a new differential SCA that performs better than traditional SCA on software FSR-based algorithms, where the leaked values are similar between rounds. SORU2 is a reconfigurable vector co-processor. It has been developed to reduce energy consumption in loop-based applications with parallelism. In addition, we propose its use for secure implementations of FSR-based algorithms. The cost overhead is discarded as the co-processor is not exclusively dedicated to the encryption algorithm. We present a co-processor configuration that executes multiple simultaneous encryptions, using different implementations and keys. From a basic implementation, which is proved to be vulnerable to SCA, we obtain an implementation where the SCA applied were unsuccessful. At compiler level, we use the framework to evaluate the effect of sequences of compiler optimization passes on a software implementation. There are many optimization passes available. The optimization sequences are combinations of the available passes. The amount of sequences is extremely high. The framework includes an algorithm for the selection of interesting sequences that require detailed evaluation. As existing compiler optimizations transform the software implementation, using different optimization sequences we can automatically generate different implementations. We propose to randomly switch between the generated implementations to increase the resistance against SCA.We propose two countermeasures. The results show that, although they increase the resistance against SCA, the resulting implementations are not secure. At bit level, we propose to exploit bit level parallelism of FSR-based implementations using pseudo bitslice implementation in a wireless node processor. The bitslice implementation is automatically obtained from the Algebraic Normal Form of the algorithm. The results show a performance improvement, avoiding timing information leakage, but increasing the vulnerability against differential SCA.We provide a secure version of the algorithm by randomly discarding part of the data obtained. The overhead in performance is negligible when compared to the original implementations. To summarize, we have proposed a set of original countermeasures at different levels that introduce randomness in FSR-based algorithms avoiding a heavy overhead on the resources required.

Optimal Control Using Feedback Linearization for a Generalized T-S Model

In this paper, a fuzzy feedback linearization is used to control nonlinear systems described by Takagi-Suengo (T-S) fuzzy systems. In this work, an optimal controller is designed using the linear quadratic regulator (LQR). The well known weighting parameters approach is applied to optimize local and global approximation and modelling capability of T-S fuzzy model to improve the choice of the performance index and minimize it. The approach used here can be considered as a generalized version of T-S method. Simulation results indicate the potential, simplicity and generality of the estimation method and the robustness of the proposed optimal LQR algorithm.

Concepções e práticas de avaliação de professores de ciências físico-químicas do ensino básico

Este estudo teve como objetivo caracterizar as concepções e práticas de avaliação de professores portugueses de Ciências Físico-Químicas do ensino básico e conhecer como estes integram a avaliação nas suas aulas no contexto de uma reorganização curricular. Realizaram-se três estudos de caso, em que participaram professores com menos de três anos de serviço. A recolha de dados consistiu na observação naturalista de aulas, entrevistas semiestruturadas e documentos fornecidos pelos participantes. Os resultados evidenciam duas concepções de avaliação das aprendizagens: avaliação da aprendizagem e avaliação para a aprendizagem. Um dos participantes evidencia uma concepção de avaliação da aprendizagem, valorizando uma avaliação de natureza sumativa. Os professores com uma concepção sobre avaliação para a aprendizagem promovem uma avaliação orientada para a melhoria das aprendizagens, valorizando o carácter formativo da avaliação. Relativamente às práticas avaliativas dos três participantes, verificou-se que os critérios de avaliação não são explicitados aos alunos, o feedback é pouco frequente e os alunos têm um papel reduzido no processo de avaliação. Todos os professores demonstram dificuldades na avaliação das competências atitudinais e processuais, sendo que, apenas um dos participantes elabora registos de observação para avaliar estas competências. Os testes constituem o principal instrumento de avaliação nas aulas dos professores participantes neste estudo, o que é coerente com uma concepção de ensino e aprendizagem ainda, marcadamente tradicional.

AtGRP7, a nuclear RNA-binding protein as a component of a circadian-regulated negative feedback loop in Arabidopsis thaliana

The endogenous clock that drives circadian rhythms is thought to communicate temporal information within the cell via cycling downstream transcripts. A transcript encoding a glycine-rich RNA-binding protein, Atgrp7, in Arabidopsis thaliana undergoes circadian oscillations with peak levels in the evening. The AtGRP7 protein also cycles with a time delay so that Atgrp7 transcript levels decline when the AtGRP7 protein accumulates to high levels. After AtGRP7 protein concentration has fallen to trough levels, Atgrp7 transcript starts to reaccumulate. Overexpression of AtGRP7 in transgenic Arabidopsis plants severely depresses cycling of the endogenous Atgrp7 transcript. These data establish both transcript and protein as components of a negative feedback circuit capable of generating a stable oscillation. AtGRP7 overexpression also depresses the oscillation of the circadian-regulated transcript encoding the related RNA-binding protein AtGRP8 but does not affect the oscillation of transcripts such as cab or catalase mRNAs. We propose that the AtGRP7 autoregulatory loop represents a “slave” oscillator in Arabidopsis that receives temporal information from a central “master” oscillator, conserves the rhythmicity by negative feedback, and transduces it to the output pathway by regulating a subset of clock-controlled transcripts.

Translational coupling by modulation of feedback repression in the IF3 operon of Escherichia coli

A pseudoknot formed by a long-range interaction in the mRNA of the initiation factor 3 (IF3) operon is involved in the translational repression of the gene encoding ribosomal protein L35 by another ribosomal protein, L20. The nucleotides forming the 5′ strand of the key stem of the pseudoknot are located within the gene for IF3, whereas those forming the 3′ strand are located 280 nt downstream, immediately upstream of the Shine–Dalgarno sequence of the gene for L35. Here we show that premature termination of IF3 translation at a nonsense codon introduced upstream of the pseudoknot results in a substantial enhancement of L20-mediated repression of L35 expression. Conversely, an increase of IF3 translation decreases repression. These results, in addition to an analysis of the effect of mutations in sequences forming the pseudoknot, indicate that IF3 translation decreases L20-mediated repression of L35 expression. We propose that ribosomes translating IF3 disrupt the pseudoknot and thereby attenuate repression. The result is a novel type of translational coupling, where unfolding of the pseudoknot by ribosomes translating IF3 does not increase expression of L35 directly, but alleviates its repression by L20.