Low-Cost Micromechanically Tunable Optical Devices: Strained Resonator Engineering, Technological Implementation and Characterization

The rapid growth of the optical communication branches and the enormous demand for more bandwidth require novel networks such as dense wavelength division multiplexing (DWDM). These networks enable higher bitrate transmission using the existing optical fibers. Micromechanically tunable optical microcavity devices like VCSELs, Fabry-Pérot filters and photodetectors are core components of these novel DWDM systems. Several air-gap based tunable devices were successfully implemented in the last years. Even though these concepts are very promising, two main disadvantages are still remaining. On the one hand, the high fabrication and integration cost and on the other hand the undesired adverse buckling of the suspended membranes. This thesis addresses these two problems and consists of two main parts: • PECVD dielectric material investigation and stress control resulting in membranes shape engineering. • Implementation and characterization of novel tunable optical devices with tailored shapes of the suspended membranes. For this purposes, low-cost PECVD technology is investigated and developed in detail. The macro- and microstress of silicon nitride and silicon dioxide are controlled over a wide range. Furthermore, the effect of stress on the optical and mechanical properties of the suspended membranes and on the microcavities is evaluated. Various membrane shapes (concave, convex and planar) with several radii of curvature are fabricated. Using this resonator shape engineering, microcavity devices such as non tunable and tunable Fabry-Pérot filters, VCSELs and PIN photodetectors are succesfully implemented. The fabricated Fabry-Pérot filters cover a spectral range of over 200nm and show resonance linewidths down to 1.5nm. By varying the stress distribution across the vertical direction within a DBR, the shape and the radius of curvature of the top membrane are explicitely tailored. By adjusting the incoming light beam waist to the curvature, the fundamental resonant mode is supported and the higher order ones are suppressed. For instance, a tunable VCSEL with 26 nm tuning range, 400µW maximal output power, 47nm free spectral range and over 57dB side mode suppresion ratio (SMSR) is demonstrated. Other technologies, such as introducing light emitting organic materials in microcavities are also investigated.

ADAM: A Decentralized Parallel Computer Architecture Featuring Fast Thread and Data Migration and a Uniform Hardware Abstraction

The furious pace of Moore's Law is driving computer architecture into a realm where the the speed of light is the dominant factor in system latencies. The number of clock cycles to span a chip are increasing, while the number of bits that can be accessed within a clock cycle is decreasing. Hence, it is becoming more difficult to hide latency. One alternative solution is to reduce latency by migrating threads and data, but the overhead of existing implementations has previously made migration an unserviceable solution so far. I present an architecture, implementation, and mechanisms that reduces the overhead of migration to the point where migration is a viable supplement to other latency hiding mechanisms, such as multithreading. The architecture is abstract, and presents programmers with a simple, uniform fine-grained multithreaded parallel programming model with implicit memory management. In other words, the spatial nature and implementation details (such as the number of processors) of a parallel machine are entirely hidden from the programmer. Compiler writers are encouraged to devise programming languages for the machine that guide a programmer to express their ideas in terms of objects, since objects exhibit an inherent physical locality of data and code. The machine implementation can then leverage this locality to automatically distribute data and threads across the physical machine by using a set of high performance migration mechanisms. An implementation of this architecture could migrate a null thread in 66 cycles -- over a factor of 1000 improvement over previous work. Performance also scales well; the time required to move a typical thread is only 4 to 5 times that of a null thread. Data migration performance is similar, and scales linearly with data block size. Since the performance of the migration mechanism is on par with that of an L2 cache, the implementation simulated in my work has no data caches and relies instead on multithreading and the migration mechanism to hide and reduce access latencies.

VADS: free art and design images for education

VADS is the online resource for visual arts. It has provided services to the academic community for 12 years and has built up a considerable portfolio of visual art collections comprising over 100,000 images that are freely available and copyright cleared for use in learning, teaching and research in the UK.

Teaching art and design : addressing issues and identifying directions.

Promueve el desarrollo profesional de los profesores especialistas en arte y diseño, tanto de los que se preparan para enseñar, como de los recién titulados o los más experimentados. Así, este recurso surge como respuesta a los debates sobre dos iniciativas de gran alcance promovidas por el gobierno: la introducción del National Currículo y la reforma de la educación y formación del profesorado. Estas medidas llevaron a los profesores de arte y diseño a aplicar, de forma rápida, el plan de estudios para Arte y a prepararse para su nuevo papel en la escuela, a través de cursos iniciales de formación. También, aborda el libro los problemas actuales en la enseñanza del arte y el diseño, e identifica las direcciones que han de seguir el desarrollo de sus futuros programas de estudios, con especial referencia a la fase de secundaria.

Complete Technology and Design.

Proporciona a los alumnos del último ciclo de secundaria, es decir, de la etapa 4 (key stage 4)los conocimientos requeridos en esta asignatura: diseño, comunicación y proyectos de diseño, materiales y sistemas electrónicos, sistemas mecánicos, ordenadores, microprocesadores y sistemas neumáticos. También, introduce a los alumnos en programas de diseño asistido por ordenador y en las técnicas de representación gráfica.

Teaching primary art and design.

Esta guía ayuda a los profesores en período de formación inicial a superar el Qualified Teacher Status (QTS), aunque también abarca áreas clave del currículo de arte y diseño para las etapas de infantil y primaria. Para ello, utiliza estudios de casos como ejemplos para el desarrollo práctico de los marcos curriculares en el aula. Asimismo, ofrece consejos prácticos sobre identificación de temas, preparación de recursos en aprendizaje, planificación y evaluación.

AQA GCSE Art and Design : student handbook.

Manual diseñado para ayudar al alumno a obtener el máximo provecho y garantizar que se cumplan los objetivos necesarios de AQA General Certificate of Secondary Education (GCSE) de Arte y Diseño, tanto en la unidad de evaluación controlada (portafolio) como en el examen. Cubre muestras de trabajos procedentes de todas las menciones para ejemplificar diferentes modos de trabajo: arte y diseño (curso completo o corto); aplicado; bellas artes; comunicación gráfica; diseño textil; diseño tridimensional; fotografía basada en la lente y en la luz. En el portafolio se incluyen proyectos y colección de trabajos que se desarrollan a lo largo del curso, necesarios para mostrar que se han cubierto todos los objetivos de evaluación. Tiene estudios de casos y otras actividades para reforzar el aprendizaje y alentar a los estudiantes a desarrollar sus habilidades creativas.

Learning to teach art and design in the secondary school : a companion to school experience.

Este texto ayuda tanto a los estudiantes que se están formando a enseñar arte y diseño como a los profesores con experiencia que han optado por asumir la responsabilidad de impartir esta materia en la etapa 3 (KS3) del programa de estudios inglés, a alumnos de catorce a diecinueve años. Ofrece un marco conceptual y práctico para la comprensión de la naturaleza diversa del arte y el diseño y proporciona apoyo y orientación para su aprendizaje y enseñanza al plantear cuestiones, preguntas ortodoxas pero también para identificar nuevas direcciones.

Art and design. Level 2. BTEC First.

El programa BTEC es un programa de estudios que permite obtener una cualificación profesional o laboral. Este recurso está preparado para ayudar al alumno en el curso BTEC First, nivel 2, sector profesional arte y diseño y se divide en dos secciones: conocimientos y destrezas; la primera sección comprende cinco unidades y la segunda sección, tres unidades. Incluye actividades de evaluación en cada unidad que cubren todos los criterios de ésta para ofrecer a los estudiantes la oportunidad de practicar sus tareas y profundizar en el conocimiento y la comprensión de la materia.

Computer-Assisted Language Learning (CALL) and trilingualism in the Basque Country. 'Aprendizaje de lenguas asistido por ordenador (CALL) y triling????smo en el Pa??s Vasco'

Resumen basado en el de la publicaci??n

Approaches for quality in pedagogical and design fundamentals in MOOCS

Resumen tomado de la publicaci??n

Modelling: promoting creativity whilst forging links between science education and design and technology education

Educational reforms in many countries currently call for the development of knowledge-based societies. In particular, emphasis is placed on the promotion of creativity, especially in the areas of science education and of design and technology education. In this paper, perceptions of the nature of creativity and of the conditions for its realization are discussed. The notion of modelling as a creative act is outlined and the scope for using modelling as a bridge between science education and design and technology education explored. A model for the creative act of modelling is proposed and its major aspects elaborated upon. Finally, strategies for forging links between the two subjects are outlined.