Modelling a cable structure for a new wind energy production device

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia Mecânica Especialização em Concepção e Produção

Three transducers for one photodetector: essays for optical communications

Dissertation presented to obtain the PhD degree in Electrical and Computer Engineering - Electronics

Understanding the internet banking adoption by Portuguese customers - a unified theory of acceptance and use of technology and perceived risk application.

Trabalho de Projeto apresentado como requisito parcial para obtenção do grau de Mestre em Estatística e Gestão de Informação

Mobilie Banking adoption: a novel in the portuguese context

Dissertação apresentada como requisito parcial para obtenção do grau de Mestre em Estatística e Gestão de Informação

An agent based architecture for material handling systems

Dissertação para obtenção do Grau de Mestre em Engenharia Electrotécnica e de Computadores

The stone and the cross. Indo-Portuguese Jesuit Architecture in Ethiopia. 1603-33

A fundação de uma missão jesuita no Norte da Etiópia em 1603, na província do Tigré, pelo enérgico Pe. Pero Pais, S. J. teólogo, construtor e historiador vindo de Goa, tomou um forte impulso com a aliança pretendida com os Portugueses pelo imperador Susénios (1619-20) para o apoio militar contra os muçulmanos; e, sobretudo, após a sua conversão oficial à Igreja Católica Romana, em 1626. Uma dúzia de inovadores edifícios foram então construídos pelos Jesuítas na região paradisíaca em torno do Lago Tana: basílicas, igrejas, palácios e jardins, complexos palatinos e eclesiásticos, colégios, etc. A tipologia em cruz latina e ornatos incisos é deliberadamente diferente das igrejas ortodoxas etíopes, circulares e em madeira. A técnica de construção em pedra e cal, ignorada na Etiópia, significou uma revolução. No presente texto procura-se determinar a quem deve ser atribuído este inédito surto construtivo, deixando de lado as teorias tradicionais de pedreiros vindos de Portugal ou de construtores locais. Com base na evidência estilística e em referências de textos da época, atribui-se a inovação a padres e “irmãos” jesuitas com experiência de arquitectos na Índia portuguesa e a construtores de Goa e de Diu, definindo a arte portuguesa na Etiópia como uma província da arquitectura indo-portuguesa na Índia, prosseguida após a expulsão dos Jesuítas (1633) com os “castelos portugueses”, ou paços acastelados da nova capital, Gondar.

Bioinspired polyethersulfone-based hollow fiber membranes as the scaffolds in renal assist device for protein-bound toxins removal from blood

Dissertation for obtaining the Master degree in Membrane Engineering

Teleoperation of a service robot using a mobile device

Teleoperation is a concept born with the rapid evolution of technology, with an intuitive meaning "operate at a distance." The first teleoperation system was created in the mid 1950s, which were handled chemicals. Remote controlled systems are present nowadays in various types of applications. This dissertation presents the development of a mobile application to perform the teleoperation of a mobile service robot. The application integrates a distributed surveillance (the result of a research project QREN) and led to the development of a communication interface between the robot (the result of another QREN project) and the vigilance system. It was necessary to specify a communication protocol between the two systems, which was implemented over a communication framework 0MQ (Zero Message Queue). For the testing, three prototype applications were developed before to perform the test on the robot.

Using an LED as a sensor and visible light communication device in a smart illumination system

The need for more efficient illumination systems has led to the proliferation of Solid-State Lighting (SSL) systems, which offer optimized power consumption. SSL systems are comprised of LED devices which are intrinsically fast devices and permit very fast light modulation. This, along with the congestion of the radio frequency spectrum has paved the path for the emergence of Visible Light Communication (VLC) systems. VLC uses free space to convey information by using light modulation. Notwithstanding, as VLC systems proliferate and cost competitiveness ensues, there are two important aspects to be considered. State-of-the-art VLC implementations use power demanding PAs, and thus it is important to investigate if regular, existent Switched-Mode Power Supply (SMPS) circuits can be adapted for VLC use. A 28 W buck regulator was implemented using a off-the-shelf LED Driver integrated circuit, using both series and parallel dimming techniques. Results show that optical clock frequencies up to 500 kHz are achievable without any major modification besides adequate component sizing. The use of an LED as a sensor was investigated, in a short-range, low-data-rate perspective. Results show successful communication in an LED-to-LED configuration, with enhanced range when using LED strings as sensors. Besides, LEDs present spectral selective sensitivity, which makes them good contenders for a multi-colour LED-to-LED system, such as in the use of RGB displays and lamps. Ultimately, the present work shows evidence that LEDs can be used as a dual-purpose device, enabling not only illumination, but also bi-directional data communication.

Product extension services deployment platform

Due to the progresses made in the branch of embedded technologies, manufacturers are becoming able to pack their shop floor level manufacturing resources with even more complex functionalities. This technological progression is radically changing the way production systems are designed and deployed, as well as, monitored and controlled. The dissemination of smart devices inside production processes confers new visibility on the production system while enabling for a more efficient and effective management of the operations. By turning the current manufacturing resources functionalities into services based on a Service Oriented Architecture (SOA), in order to expose them as a service to the user, the binomial manufacturing resource/service will push the entire manufacturing enterprise visibility to another level while enabling the global optimization of the operations and processes of a production system while, at the same time, supporting its accommodation to the operational spike easily and with reduced impact on production. The present work implements a Cloud Manufacturing infrastructure for achieving the resource/service value-added i.e. to facilitate the creation of services that are the composition of currently available atomic services. In this context, manufacturing resource virtualization (i.e. formalization of resources capabilities into services accessible inside and outside the enterprise) and semantic representation/description are the pillars for achieving resource service composition. In conclusion, the present work aims to act on the manufacturing resource layer where physical resources and shop floor capabilities are going to be provided to the user as a SaaS (Software as a Service) and/or IaaS (Infrastructure as a Service).

Reconfigurable photonic logic architecture

The amorphous silicon photo-sensor studied in this thesis, is a double pin structure (p(a-SiC:H)-i’(a-SiC:H)-n(a-SiC:H)-p(a-SiC:H)-i(a-Si:H)-n(a-Si:H)) sandwiched between two transparent contacts deposited over transparent glass thus with the possibility of illumination on both sides, responding to wave-lengths from the ultra-violet, visible to the near infrared range. The frontal il-lumination surface, glass side, is used for light signal inputs. Both surfaces are used for optical bias, which changes the dynamic characteristics of the photo-sensor resulting in different outputs for the same input. Experimental studies were made with the photo-sensor to evaluate its applicability in multiplexing and demultiplexing several data communication channels. The digital light sig-nal was defined to implement simple logical operations like the NOT, AND, OR, and complex like the XOR, MAJ, full-adder and memory effect. A pro-grammable pattern emission system was built and also those for the validation and recovery of the obtained signals. This photo-sensor has applications in op-tical communications with several wavelengths, as a wavelength detector and to execute directly logical operations over digital light input signals.

An agent based architecture to support monitoring in plug and produce manufacturing systems using knowledge extraction

In recent years a set of production paradigms were proposed in order to capacitate manufacturers to meet the new market requirements, such as the shift in demand for highly customized products resulting in a shorter product life cycle, rather than the traditional mass production standardized consumables. These new paradigms advocate solutions capable of facing these requirements, empowering manufacturing systems with a high capacity to adapt along with elevated flexibility and robustness in order to deal with disturbances, like unexpected orders or malfunctions. Evolvable Production Systems propose a solution based on the usage of modularity and self-organization with a fine granularity level, supporting pluggability and in this way allowing companies to add and/or remove components during execution without any extra re-programming effort. However, current monitoring software was not designed to fully support these characteristics, being commonly based on centralized SCADA systems, incapable of re-adapting during execution to the unexpected plugging/unplugging of devices nor changes in the entire system’s topology. Considering these aspects, the work developed for this thesis encompasses a fully distributed agent-based architecture, capable of performing knowledge extraction at different levels of abstraction without sacrificing the capacity to add and/or remove monitoring entities, responsible for data extraction and analysis, during runtime.

Architecture and mosaics in recently discovered Palaeochristian basilicas

The excavations of the Dericik Early Christian Basilicas revealed the importance of the surrounding area of Bursa for understanding Early Christianity between the Late Roman and Early Byzantine periods. In the salvage excavations of 2001, the basic plan of the basilica (nave, narthex, presbyterium and apse) was revealed. The most important artefacts uncovered in that year were the mosaic pavements with geometric and plant ornaments and a grave located in the North Eastern corner of the church. The mosaic of the basilica was laid with the opus tessellatum technique on a thick mortar foundation with white, red, yellow, olive green and dark blue tesserae. A refrigerium scene is represented in the middle of the narthex mosaic. The mosaic in the centre of the nave is divided into parts, one of which with figures of birds inside octagons. In the transitional area between the nave and apse, three heavily damaged inscriptions have been conserved each of three or four lines, one of them indicating the wish of Epituchanos, diakôn, a church member.

Portuguese plain architecture: history opening a closed sequence

The paper will address George Kubler’s Portuguese Plain Architecture [PPA] (1972) and its effect in Portuguese architectural practice. Kubler’s philosophy of art history implied that closed sequences of objects could be opened by several reasons. Thus, it will be argued that there is an effect upon Portuguese architecture post 1974, that is apparent by the reemergence of some of the form classes treated by Kubler. This was mostly achieved through the popularity of Kubler’s book within architectural practice, scholarship and moreover by the establishment of the term “Plain Architecture” in portuguese architectural vocabulary. Plain Architecture of the seventeenth and eighteenth centuries shared some qualities with the architecture to be built in post‑revolutionary Portugal, most importantly the effect that could be achieved with low budget buildings that were responding to a situation of crisis, and simultaneously exhaled aristocratic sparsity. The connection of PPA with the ideological attributes of early modernism and the political context of the time catalysed the reemergence of a new order of Portuguese Plain that resonates still in contemporary architecture.