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.

User Profile Management and Selection in Context-Aware Service Platforms for Networks Beyond 3G

In recent years, progress in the area of mobile telecommunications has changed our way of life, in the private as well as the business domain. Mobile and wireless networks have ever increasing bit rates, mobile network operators provide more and more services, and at the same time costs for the usage of mobile services and bit rates are decreasing. However, mobile services today still lack functions that seamlessly integrate into users’ everyday life. That is, service attributes such as context-awareness and personalisation are often either proprietary, limited or not available at all. In order to overcome this deficiency, telecommunications companies are heavily engaged in the research and development of service platforms for networks beyond 3G for the provisioning of innovative mobile services. These service platforms are to support such service attributes. Service platforms are to provide basic service-independent functions such as billing, identity management, context management, user profile management, etc. Instead of developing own solutions, developers of end-user services such as innovative messaging services or location-based services can utilise the platform-side functions for their own purposes. In doing so, the platform-side support for such functions takes away complexity, development time and development costs from service developers. Context-awareness and personalisation are two of the most important aspects of service platforms in telecommunications environments. The combination of context-awareness and personalisation features can also be described as situation-dependent personalisation of services. The support for this feature requires several processing steps. The focus of this doctoral thesis is on the processing step, in which the user’s current context is matched against situation-dependent user preferences to find the matching user preferences for the current user’s situation. However, to achieve this, a user profile management system and corresponding functionality is required. These parts are also covered by this thesis. Altogether, this thesis provides the following contributions: The first part of the contribution is mainly architecture-oriented. First and foremost, we provide a user profile management system that addresses the specific requirements of service platforms in telecommunications environments. In particular, the user profile management system has to deal with situation-specific user preferences and with user information for various services. In order to structure the user information, we also propose a user profile structure and the corresponding user profile ontology as part of an ontology infrastructure in a service platform. The second part of the contribution is the selection mechanism for finding matching situation-dependent user preferences for the personalisation of services. This functionality is provided as a sub-module of the user profile management system. Contrary to existing solutions, our selection mechanism is based on ontology reasoning. This mechanism is evaluated in terms of runtime performance and in terms of supported functionality compared to other approaches. The results of the evaluation show the benefits and the drawbacks of ontology modelling and ontology reasoning in practical applications.

Posicionando Digital.CSIC como un elemento clave en el Sistema de Gestión de la Información Científica del CSIC

Primera conferencia. Bibliotecas y Repositorios Digitales: Gestión del Conocimiento, Acceso Abierto y Visibilidad Latinoamericana. (BIREDIAL) Mayo 9 al 11 de 2011. Bogotá, Colombia.

Voices for writing essays, reports, web pages, blogs etc.

Looks at the different ways we write for different audiences.

Mapoteca colombiana: colección de los títulos de todos los mapas, planos, vistas, etc., relativos a la América española, Brasil e islas adyacentes, arreglada cronológicamente y precedida de una introducción sobre la Historia cartográfica de América

Obra que compila el listado de los materiales cartográficos de América, identificados por Ezequiel Uricoechea durante su estadía en Europa, particularmente en la mapoteca de la Biblioteca Real de Bruselas. Esta obra se constituyó en el principal catálogo de mapas impresos sobre la Nueva Granada del siglo XIX.

Chucherías de maíz, caramelos, chicles, etc.

Es suplemento de la revista Padres y Maestros núm. 276.- Por un error de impresión falta la mitad de este suplemento

La opinión del profesorado de las titulaciones de magisterio : ventajas y dificultades en el proceso de diseño de los etc's.

Resumen basado en el de la publicación

ETC : English Through Contents.

Resumen tomado de la web del Departamento de Educación

??Hay que efectuar retenciones a cuenta sobre el IRPF a los profesores, ponentes, conferenciantes, etc. que colaboran con nuestras asociaciones?

El reciente Real Decreto 113/1998 de 30 de enero especifica que se considerar??n comprendidas entre las actividades a retener las de los profesores, conferencias, seminarios y cursillos que no se presenten como consecuencia de una relaci??n laboral.

Lo sabe ETC, yo lo sabré : educación vial : educación primaria segundo y tercer ciclo.

Unidad didáctica sobre el tema transversal la educación vial dirigido al alumnado del segundo y tercer ciclo de la educación primaria. El objetivo es que el alumnado adquiera hábitos de comportamiento de educación vial para disfrutar mejor de la ciudad. Contiene el manual y la guía didáctica. Los contenidos que se desarrollan son: reconocimiento de las señales de tráfico, comprensión y respeto de las normas de circulación, adquisición de hábitos de no competitividad en la circulación, circulación con vehículos de dos ruedas, reconocimiento de las limitaciones de la bicicleta, normas de utilización de los servicios de transporte público y reconocimiento de las normas de utilización de vehículos particulares.

Tercer coloquio sobre Geografía en Salamanca : se estudiaron interesantes temas del paisaje rural, cultivos, etc. Asistieron numerosos Catedráticos de Universidades y de Institutos, Inspectores y Profesores de diversas enseñanzas.

Se exponen los resultados de la celebración del tercer coloquio sobre Geografía, que tuvo lugar los 25, 26 y 27 de octubre de 1985, en Salamanca. Estuvo organizado por la Asociación Española para el Progreso de las Ciencias. Se recogen resúmenes de las ponencias de dicho coloquio. Destacan la de Antonio López Gómez, Catedrático de Geografía de la Universidad de Valencia, titulada La Geografía Agraria en la Enseñanza Media: el ejemplo de las huertas levantinas, la de Pedro Plana, Profesor de Geografía, que versa sobre el método comparativo en la enseñanza de la geografía a los alumnos del bachillerato y la presentada conjuntamente por José Manuel Casas Torrea y Salvador Mensua Fernández, bajo el título Un método de investigación en el estudio de la utilización del suelo. Por último se señala que fuera de programa, el bibliotecario de la Institución para Formación del Profesorado de Enseñanza Laboral, José Sanz García, presentó a los congresistas una valorada relación de trabajos monográficos sobre Geografía Comarcal, existente en la citada Institución, cuya relación se incluye.

Violência na escola : implicações na prática docente

Este estudo aborda fatos veiculados a violência na escola mostrando situações em que docentes e estudantes são ameaçados e agredidos por outros sujeitos vinculados a escola ou a comunidade. Tendo como questão norteadora a violência na escola e suas implicações na prática docente. Nesse sentido procurou-se abordar as mais recentes literaturas acerca do tema em destaque a fim de compreendermos a realidade da qual nos propomos estudar. A finalidade dessa pesquisa é compreender de que maneira esse tipo de violência afeta a vida dos sujeitos em uma escola da Rede Pública Municipal de Olinda-PE, através do levantamento de informações acerca do tipo de violência praticada no contexto escolar; identificando os fatos que levam a prática dessa modalidade de violência por parte dos sujeitos da escola e analisar os fatores que contribuem para ocorrência desse fenômeno no ambiente escolar. Metodologicamente optamos pela abordagem qualitativa descritiva e quantitativa objetivando o aprofundamento da temática proposta, utilizando-se como técnica de coleta de dados o questionário e o inquérito por entrevista. A análise dos dados partiu dos discursos de Bardin (2002), através do método análise de conteúdo. Os autores que subsidiaram o estudo foram: Adorno (1971); Bourdieu (2001); Peralva (2000), Abramovay (2002); Debarbieux (2002); Fante (2005) dentre outros que tratam da violência na escola numa perspectiva histórico-social. Assim, pudemos constatar que essa modalidade de violência origina-se na sociedade e se dissemina através de danos físicos ou simbólicos, que são aplicados de modo individual ou grupos. E que num plano maior muitas vezes é associada à pobreza, a desigualdade social, desemprego e falhas de comunicação. É também oposta a utilização da razão, aceitação e diálogo, estando relacionados a diversos tipos de poderes em todos os tipos de relações entre os seres humanos. Contudo, concluiu-se que os sujeitos não estão preparados para lidar com o fenômeno da violência escolar e que é preciso abrir espaços para que todos participem da busca de soluções para evitar e combater o problema.