Überwachung der Vorspannkraft Externer Spannglieder mit Hilfe der Modalanalyse

Aufgrund ihrer Vorteile hinsichtlich Dauerhaftigkeit und Bauwerkssicherheit ist in Deutschland seit 1998 die externe Vorspannung in Hohlkastenbrücken zur Regelbauweise geworden. Durch Verwendung der austauschbaren externen Vorspannung verspricht man sich im Brückenbau weitere Verbesserungen der Robustheit und damit eine Verlängerung der Lebensdauer. Trotz des besseren Korrosionsschutzes im Vergleich zur internen Vorspannung mit Verbund sind Schäden nicht völlig auszuschließen. Um die Vorteile der externen Vorspannung zu nutzen, ist daher eine periodische Überwachung der Spanngliedkräfte, z. B. während der Hauptprüfung des Bauwerks, durchzuführen. Für die Überwachung der Spanngliedkräfte bei Schrägseilbrücken haben sich die Schwingungsmessmethoden als wirtschaftlich und leistungsfähig erwiesen. Für die Übertragung der Methode auf den Fall der externen Vorspannung, wo kürzere Schwingungslängen vorliegen, waren zusätzliche Untersuchungen hinsichtlich der effektiven Schwingungslänge, der Randbedingungen sowie der effektiven Biegesteifigkeit erforderlich. Im Rahmen der vorliegenden Arbeit wurde das Modellkorrekturverfahren, basierend auf der iterativen Anpassung eines F.E.-Modells an die identifizierten Eigenfrequenzen und Eigenformen des Spanngliedes, für die Bestimmung der Spanngliedkräfte verwendet. Dieses Verfahren ermöglicht die Berücksichtigung der Parameter (Schwingungslänge, Randbedingungen und effektive Biegesteifigkeit) bei der Identifikation der effektiven Spanngliedkräfte. Weiterhin ist eine Modellierung jeder beliebigen Spanngliedausbildung, z. B. bei unterschiedlichen Querschnitten in den Verankerungs- bzw. Umlenkbereichen, gewährleistet. Zur Anwendung bei der Ermittlung der Spanngliedkräfte wurde eine spezielle Methode, basierend auf den besonderen dynamischen Eigenschaften der Spannglieder, entwickelt, bei der die zuvor genannten Parameter innerhalb jedes Iterationsschrittes unabhängig korrigiert werden, was zur Robustheit des Identifikationsverfahrens beiträgt. Das entwickelte Verfahren ist in einem benutzerfreundlichen Programmsystem implementiert worden. Die erzielten Ergebnisse wurden mit dem allgemeinen Identifikationsprogramm UPDATE_g2 verglichen; dabei ist eine sehr gute Übereinstimmung festgestellt worden. Beim selbst entwickelten Verfahren wird die benötigte Rechenzeit auf ca. 30 % reduziert [100 sec à 30 sec]. Es bietet sich daher für die unmittelbare Auswertung vor Ort an. Die Parameteridentifikationsverfahren wurden an den Spanngliedern von insgesamt sechs Brücken (vier unterschiedliche Spannverfahren) angewendet. Die Anzahl der getesteten Spannglieder beträgt insgesamt 340. Die Abweichung zwischen den durch Schwingungs-messungen identifizierten und gemessenen (bei einer Brücke durch eine Abhebekontrolle) bzw. aufgebrachten Spanngliedkräften war kleiner als 3 %. Ferner wurden die Auswirkungen äußerer Einflüsse infolge Temperaturschwankungen und Verkehr bei den durchgeführten Messungen untersucht. Bei der praktischen Anwendung sind Besonderheiten aufgetreten, die durch die Verwendung des Modellkorrekturverfahrens weitgehend erfasst werden konnten. Zusammenfassend lässt sich sagen, dass die Verwendung dieses Verfahrens die Genauigkeit im Vergleich mit den bisherigen Schwingungsmessmethoden beachtlich erhöht. Ferner wird eine Erweiterung des Anwendungsbereiches auch auf Spezialfälle (z. B. bei einem unplanmäßigen Anliegen) gewährleistet.

A Virtual Machine for a Type-omega Denotational Proof Language

In this thesis, I designed and implemented a virtual machine (VM) for a monomorphic variant of Athena, a type-omega denotational proof language (DPL). This machine attempts to maintain the minimum state required to evaluate Athena phrases. This thesis also includes the design and implementation of a compiler for monomorphic Athena that compiles to the VM. Finally, it includes details on my implementation of a read-eval-print loop that glues together the VM core and the compiler to provide a full, user-accessible interface to monomorphic Athena. The Athena VM provides the same basis for DPLs that the SECD machine does for pure, functional programming and the Warren Abstract Machine does for Prolog.

Curriculum sequencing for an e-learning system based on learning styles

This work shows the use of adaptation techniques involved in an e-learning system that considers students' learning styles and students' knowledge states. The mentioned e-learning system is built on a multiagent framework designed to examine opportunities to improve the teaching and to motivate the students to learn what they want in a user-friendly and assisted environment

Productividad, innovación y uso de tecnologías de información y las comunicaciones (tic) como factores de desarrollo de la micro, pequeña y mediana empresa (mipyme) en Bogotá.

Las TIC han impactado en el funcionamiento de las organizaciones y han aportado a su proceso evolutivo, generando diversos efectos de acuerdo a la función que estas cumplen dentro de la organización. Las TIC como consecuencia se convierten en una estrategia de gestión en un entorno complejo donde permiten alcanzar mejoras en la organización social, la actividad económica, el bienestar y el acceso a la información y el conocimiento. (Cáceres Carrasco & Aceytuno Pérez, 2008)Con el fin de entender los beneficios de las TIC, se deben brindar a los directores herramientas que permitan formular modelos de negocios efectivos de cara a los mercados y enfocadas a la satisfacción de los clientes. Adicionalmente, para las organizaciones el añadir valor, no sólo hace referencia al servicio que están prestando; hay otros factores diferentes al uso de herramientas TIC y la innovación que también son igual de importantes como: los procesos de apoyo, de gestión que se encuentran de fondo y que hacen posible brindar un servicio al mercado, en estos procesos se encuentran aplicaciones de procedimientos amigables y fáciles de articular, temas como la responsabilidad empresarial, relación y comunicación con competidores dentro del mismo sector, es justamente en las relaciones con los clientes, que las TIC y el uso de Internet puede tener incidencia en los modelos de negocios a través de actividades como el comercio electrónico, el mercadeo electrónico, el mercadeo en línea entre otros. Existen investigaciones acerca de estos temas: innovación, TI, pero no se han establecido relaciones entre ellos, debido a su novedad. Diferentes experiencias laborales de los investigadores en el uso de las TIC como herramienta en la organización de información permiten que surja la idea de llevar a cabo este proyecto abarcando la realidad bogotana de las MiPyme. La presente investigación con un enfoque cualitativo hace una revisión bibliográfica, y bajo la mirada teórica se analiza la relación que tienen los factores de desarrollo que se evidenciaron como son la innovación y el uso de herramientas TIC, como variables dependientes de la productividad de las MiPyme en Bogotá, Colombia, involucrando temas que se relacionan con distintos campos como la tecnología, políticas gubernamentales, y economía.

Projecto e parametrização: uma torre evolutiva

A exposição directa de programas com ambientes user friendly, de fácil utilização e adaptação (não sendo necessário conhecimentos complementares de informática por parte da maioria dos seus utilizadores) resultou na inclusão das linguagens destes sistemas digitais na prática de arquitectura, gerando novas tendências e novos princípios no método de concepção individual. Esta implementação de novas técnicas de desenvolvimento revelam uma mudança de paradigma na arquitectura cuja introdução de desenhos assistidos por computador (CAD) no decorrer das fases de concepção de projecto, adoptam grande destaque, não só devido à facilidade de visualização de imagens, mas também à simplificação da modelação através de algoritmos e operações matemáticas complexas. Na actualidade, a crescente necessidade de independência destas aplicações restritiva, obriga o utilizador a procurar instrumentos mais flexíveis e personalizáveis . A presente dissertação desenvolve-se segundo a descrição do desenvolvimento de uma proposta de intervenção, cujo método procura explorar as potencialidades da parametrização através de manipuladores. Com a programação das variáveis e de constantes , o decorrer de processos como tentativa e erro, transmitem resultados não expectáveis, que através da selecção, podem justificar as decisões conceptuais.

Elementos-Chave para a Gestão Eficaz da Emergência num Complexo Educativo

Planos de emergência bem sucedidos devem ser funcionais, realistas, amigos do utilizador e inteligíveis. Este estudo descritivo tem como objetivo analisar a implementação de Medidas de Autoproteção (que passou a ser obrigatória, em Portugal, desde 2009) durante um período de cinco anos, num grande complexo escolar ocupado por 500 funcionários e 3000 crianças/alunos. Este estabelecimento de ensino consiste em vários edifícios desde a creche ao ensino secundário e está classificado numa categoria de risco de incêndio muito elevada. Desde 2009 até 2012 foram realizadas sessões de formação destinadas aos alunos e funcionários, bem como ações de formação sobre combate a incêndios e evacuação para as equipas de segurança. Como os exercícios de evacuação são cruciais para testar o plano de emergência e familiarizar o pessoal com as tarefas, todos os anos são realizados Simulacros de Incêndio. A fim de avaliar a sua eficácia foram recolhidos dados através de observação não participante, fotos e vídeos. A gestão de emergência neste estabelecimento escolar evidenciou ir para além das exigências legais e, ao dar um bom exemplo, tanto na escola como na comunidade, contribuiu para aumentar a segurança dos alunos e das suas famílias. / Successful emergency plans must be functional, realistic, user-friendly and understandable. This descriptive study aims to analyse the implementation of Fire Self-Protection Measures (which became mandatory, in Portugal, since 2009) during a five-year period in a large school compound occupied by 500 employees and 3000 children/students. This educational facility consists of several buildings from nursery school to high school and it’s classified in a very high fire risk category. Since 2009 until 2012 we carried out training sessions for students and school staff, as well as training courses about fire fighting and evacuation, for safety teams. Because evacuation drills are crucial for testing the emergency plan and to familiarize personnel with tasks, each year we do properly conducted fire drills. In order to evaluate it’s effectiveness, we collected data through non-participant observation, photos and videos. The school emergency management has proven to go beyond the legal requirements and by setting a good example both in school and community, it enhances the safety of students and their families.

Exploiting CAFS-ISP

In the summer of 1982, the ICLCUA CAFS Special Interest Group defined three subject areas for working party activity. These were: 1) interfaces with compilers and databases, 2) end-user language facilities and display methods, and 3) text-handling and office automation. The CAFS SIG convened one working party to address the first subject with the following terms of reference: 1) review facilities and map requirements onto them, 2) "Database or CAFS" or "Database on CAFS", 3) training needs for users to bridge to new techniques, and 4) repair specifications to cover gaps in software. The working party interpreted the topic broadly as the data processing professional's, rather than the end-user's, view of and relationship with CAFS. This report is the result of the working party's activities. The report content for good reasons exceeds the terms of reference in their strictest sense. For example, we examine QUERYMASTER, which is deemed to be an end-user tool by ICL, from both the DP and end-user perspectives. First, this is the only interface to CAFS in the current SV201. Secondly, it is necessary for the DP department to understand the end-user's interface to CAFS. Thirdly, the other subjects have not yet been addressed by other active working parties.

Solving surface structures from normal incidence X-ray standing wave data

A program is provided to determine structural parameters of atoms in or adsorbed on surfaces by refinement of atomistic models towards experimentally determined data generated by the normal incidence X-ray standing wave (NIXSW) technique. The method employs a combination of Differential Evolution Genetic Algorithms and Steepest Descent Line Minimisations to provide a fast, reliable and user friendly tool for experimentalists to interpret complex multidimensional NIXSW data sets.

Object-based three-dimensional X-ray imaging

A form of three-dimensional X-ray imaging, called Object 3-D, is introduced, where the relevant subject material is represented as discrete ‘objects’. The surface of each such object is derived accurately from the projections of its outline, and of its other discontinuities, in about ten conventional X-ray views, distributed in solid angle. This technique is suitable for many applications, and permits dramatic savings in radiation exposure and in data acquisition and manipulation. It is well matched to user-friendly interactive displays.

Suitability of pesticide risk indicators for less developed countries: a comparison

Pesticide risk indicators provide simple support in the assessment of environmental and health risks from pesticide use, and can therefore inform policies to foster a sustainable interaction of agriculture with the environment. For their relative simplicity, indicators may be particularly useful under conditions of limited data availability and resources, such as in Less Developed Countries (LDCs). However, indicator complexity can vary significantly, in particular between those that rely on an exposure–toxicity ratio (ETR) and those that do not. In addition, pesticide risk indicators are usually developed for Western contexts, which might cause incorrect estimation in LDCs. This study investigated the appropriateness of seven pesticide risk indicators for use in LDCs, with reference to smallholding agriculture in Colombia. Seven farm-level indicators, among which 3 relied on an ETR (POCER, EPRIP, PIRI) and 4 on a non-ETR approach (EIQ, PestScreen, OHRI, Dosemeci et al., 2002), were calculated and then compared by means of the Spearman rank correlation test. Indicators were also compared with respect to key indicator characteristics, i.e. user friendliness and ability to represent the system under study. The comparison of the indicators in terms of the total environmental risk suggests that the indicators not relying on an ETR approach cannot be used as a reliable proxy for more complex, i.e. ETR, indicators. ETR indicators, when user-friendly, show a comparative advantage over non-ETR in best combining the need for a relatively simple tool to be used in contexts of limited data availability and resources, and for a reliable estimation of environmental risk. Non-ETR indicators remain useful and accessible tools to discriminate between different pesticides prior to application. Concerning the human health risk, simple algorithms seem more appropriate for assessing human health risk in LDCs. However, further research on health risk indicators and their validation under LDC conditions is needed.

Non-visual and multisensory BCI systems: present and future

During the past decade, brain–computer interfaces (BCIs) have rapidly developed, both in technological and application domains. However, most of these interfaces rely on the visual modality. Only some research groups have been studying non-visual BCIs, primarily based on auditory and, sometimes, on somatosensory signals. These non-visual BCI approaches are especially useful for severely disabled patients with poor vision. From a broader perspective, multisensory BCIs may offer more versatile and user-friendly paradigms for control and feedback. This chapter describes current systems that are used within auditory and somatosensory BCI research. Four categories of noninvasive BCI paradigms are employed: (1) P300 evoked potentials, (2) steady-state evoked potentials, (3) slow cortical potentials, and (4) mental tasks. Comparing visual and non-visual BCIs, we propose and discuss different possible multisensory combinations, as well as their pros and cons. We conclude by discussing potential future research directions of multisensory BCIs and related research questions

A GUI for online presentation of steel and steelmaking ladle temperature data and simulation.

Continuous casting is a casting process that produces steel slabs in a continuous manner with steel being poured at the top of the caster and a steel strand emerging from the mould below. Molten steel is transferred from the AOD converter to the caster using a ladle. The ladle is designed to be strong and insulated. Complete insulation is never achieved. Some of the heat is lost to the refractories by convection and conduction. Heat losses by radiation also occur. It is important to know the temperature of the melt during the process. For this reason, an online model was previously developed to simulate the steel and ladle wall temperatures during the ladle cycle. The model was developed as an ODE based model using grey box modeling technique. The model’s performance was acceptable and needed to be presented in a user friendly way. The aim of this thesis work was basically to design a GUI that presents steel and ladle wall temperatures calculated by the model and also allow the user to make adjustments to the model. This thesis work also discusses the sensitivity analysis of different parameters involved and their effects on different temperature estimations.

A tool for standardized collector performance calculations including PVT

A tool for standardized calculation of solar collector performance has been developed in cooperation between SP Technical Research Institute of Sweden, DTU Denmark and SERC Dalarna University. The tool is designed to calculate the annual performance of solar collectors at representative locations in Europe. The collector parameters used as input in the tool are compiled from tests according to EN12975, without any intermediate conversions. The main target group for this tool is test institutes and certification bodies that are intended to use it for conversion of collector model parameters (derived from performance tests) into a more user friendly quantity: the annual energy output. The energy output presented in the tool is expressed as kWh per collector module. A simplified treatment of performance for PVT collectors is added based on the assumption that the thermal part of the PVT collector can be tested and modeled as a thermal collector, when the PV electric part is active with an MPP tracker in operation. The thermal collector parameters from this operation mode are used for the PVT calculations. © 2012 The Authors.

Development Of Water Pollution Early Warning System For Oyster Harvesting Areas

The objective of this study is to develop a Pollution Early Warning System (PEWS) for efficient management of water quality in oyster harvesting areas. To that end, this paper presents a web-enabled, user-friendly PEWS for managing water quality in oyster harvesting areas along Louisiana Gulf Coast, USA. The PEWS consists of (1) an Integrated Space-Ground Sensing System (ISGSS) gathering data for environmental factors influencing water quality, (2) an Artificial Neural Network (ANN) model for predicting the level of fecal coliform bacteria, and (3) a web-enabled, user-friendly Geographic Information System (GIS) platform for issuing water pollution advisories and managing oyster harvesting waters. The ISGSS (data acquisition system) collects near real-time environmental data from various sources, including NASA MODIS Terra and Aqua satellites and in-situ sensing stations managed by the USGS and the NOAA. The ANN model is developed using the ANN program in MATLAB Toolbox. The ANN model involves a total of 6 independent environmental variables, including rainfall, tide, wind, salinity, temperature, and weather type along with 8 different combinations of the independent variables. The ANN model is constructed and tested using environmental and bacteriological data collected monthly from 2001 – 2011 by Louisiana Molluscan Shellfish Program at seven oyster harvesting areas in Louisiana Coast, USA. The ANN model is capable of explaining about 76% of variation in fecal coliform levels for model training data and 44% for independent data. The web-based GIS platform is developed using ArcView GIS and ArcIMS. The web-based GIS system can be employed for mapping fecal coliform levels, predicted by the ANN model, and potential risks of norovirus outbreaks in oyster harvesting waters. The PEWS is able to inform decision-makers of potential risks of fecal pollution and virus outbreak on a daily basis, greatly reducing the risk of contaminated oysters to human health.

Equity and Efficiency in Education: motivations and targets

The recently released "Educational PAC" attempts to place basic education at the center of the social debate. We have subsidized this debate, offering a diagnosis of how different education levels can impact individuals' lives through broad and easily interpreted indicators. Initially, we analyze how much each educational level reaches the poorest population. For example, how are those in the bottom strata of income distribution benefited by childcare centers, private secondary education, public university or adult education. The next step is to quantify the return of educational actions, such as their effects on employability and an individual's wages, and even health as perceived by the individual, be that individual poor, middle class or elite. The next part of the research presents evidence of how the main characters in education, aka mothers, fathers and children, regard education. The site available with the research presents a broad, user-friendly database, which will allow interested parties to answer their own questions relative to why people do not attend school, the time spent in the educational system and returns to education, which can all be cross-sectioned with a wide array of socio-demographic attributes (gender, income, etc.) and school characteristics (is it public, are school meals offered, etc.) to find answers to: why do young adults of a certain age not attend school? Why do they miss classes? How long is the school day? Aside from the whys and hows of teaching, the research calculates the amount of time spent in school, resulting from a combination between absence rates, evasion raters and length of the school day. The study presents ranks of indicators referring to objective and subjective aspects of education, such as the discussion of the advantages and care in establishing performance based incentives that aim at guiding the states in the race for better educational indicators.