Design of improved rail-to-rail low-distortion and low-stress switches in advanced CMOS technologies

This paper describes the efficient design of an improved and dedicated switched-capacitor (SC) circuit capable of linearizing CMOS switches to allow SC circuits to reach low distortion levels. The described circuit (SC linearization control circuit, SLC) has the advantage over conventional clock-bootstrapping circuits of exhibiting low-stress, since large gate voltages are avoided. This paper presents exhaustive corner simulation results of a SC sample-and-hold (S/H) circuit which employs the proposed and optimized circuits, together with the experimental evaluation of a complete 10-bit ADC utilizing the referred S/H circuit. These results show that the SLC circuits can reduce distortion and increase dynamic linearity above 12 bits for wide input signal bandwidths.

Sistema de visão para percepção e navegação de um UAV Quadrotor

Mestrado em Engenharia Electrotécnica e de Computadores

Melhoria do planeamento programação e controlo de produção (ppcp) de uma empresa de calçado

Atualmente o sistema produtivo do tipo job shop é muito comum nas PMEs (Pequenas e Médias Empresas). Estas empresas trabalham por encomenda. Produzem grande variedade de modelos, e em pequenas quantidades. Os prazos de entrega são um fator de elevada importância, pois os clientes exigem um produto de qualidade no tempo certo. O presente trabalho, pretende criar uma ferramenta de programação da produção para a secção da costura, usando dados reais da empresa, que tem uma implantação do tipo job shop com máquinas multi-operação (Multi-Purpose -Machines Job Shop). No final, são reunidas as principais conclusões e perspetivados futuros desenvolvimentos. Os resultados obtidos comprovam que o algoritmo desenvolvido, com base no algoritmo de Giffler & Thompson, consegue obter com grande precisão e de forma rápida o escalonamento / balanceamento da secção da costura. Com a ferramenta criada, a empresa otimiza a programação da secção da costura e fornece informação importante á gestão da produção, possibilitando uma melhoria do planeamento da empresa.

Diagnóstico ambiental de duas empresas

Mestrado em Engenharia Química - Ramo Tecnologias de Protecção Ambiental

CrimsonHex: a service oriented repository of specialised learning objects

The corner stone of the interoperability of eLearning systems is the standard definition of learning objects. Nevertheless, for some domains this standard is insufficient to fully describe all the assets, especially when they are used as input for other eLearning services. On the other hand, a standard definition of learning objects in not enough to ensure interoperability among eLearning systems; they must also use a standard API to exchange learning objects. This paper presents the design and implementation of a service oriented repository of learning objects called crimsonHex. This repository is fully compliant with the existing interoperability standards and supports new definitions of learning objects for specialized domains. We illustrate this feature with the definition of programming problems as learning objects and its validation by the repository. This repository is also prepared to store usage data on learning objects to tailor the presentation order and adapt it to learner profiles.

Balancing and lot-sizing mixed-model lines in the footwear industry

This report describes the full research proposal for the project \Balancing and lot-sizing mixed-model lines in the footwear industry", to be developed as part of the master program in Engenharia Electrotécnica e de Computadores - Sistemas de Planeamento Industrial of the Instituto Superior de Engenharia do Porto. The Portuguese footwear industry is undergoing a period of great development and innovation. The numbers speak for themselves, Portugal footwear exported 71 million pairs of shoes to over 130 countries in 2012. It is a diverse sector, which covers different categories of women, men and children shoes, each of them with various models. New and technologically advanced mixed-model assembly lines are being projected and installed to replace traditional mass assembly lines. Obviously there is a need to manage them conveniently and to improve their operations. This work focuses on balancing and lot-sizing stitching mixed-model lines in a real world environment. For that purpose it will be fundamental to develop and evaluate adequate effective solution methods. Different objectives may be considered, which are relevant for the companies, such as minimizing the number of workstations, and minimizing the makespan, while taking into account a lot of practical restrictions. The solution approaches will be based on approximate methods, namely by resorting to metaheuristics. To show the impact of having different lots in production the initial maximum amount for each lot is changed and a Tabu Search based procedure is used to improve the solutions. The developed approaches will be evaluated and tested. A special attention will be given to the solution of real applied problems. Future work may include the study of other neighbourhood structures related to Tabu Search and the development of ways to speed up the evaluation of neighbours, as well as improving the balancing solution method.

Navegação web anónima e segura

A Web aproximou a humanidade dos seus pares a um nível nunca antes visto. Com esta facilidade veio também o cibercrime, o terrorismo e outros fenómenos característicos de uma sociedade tecnológica, plenamente informatizada e onde as fronteiras terrestres pouco importam na limitação dos agentes ativos, nocivos ou não, deste sistema. Recentemente descobriu-se que as grandes nações “vigiam” atentamente os seus cidadãos, desrespeitando qualquer limite moral e tecnológico, podendo escutar conversas telefónicas, monitorizar o envio e receção de e-mails, monitorizar o tráfego Web do cidadão através de poderosíssimos programas de monitorização e vigilância. Noutros cantos do globo, nações em tumulto ou envoltas num manto da censura perseguem os cidadãos negando-lhes o acesso à Web. Mais mundanamente, há pessoas que coagem e invadem a privacidade de conhecidos e familiares, vasculhando todos os cantos dos seus computadores e hábitos de navegação. Neste sentido, após o estudo das tecnologias que permitem a vigilância constante dos utilizadores da Web, foram analisadas soluções que permitem conceder algum anónimato e segurança no tráfego Web. Para suportar o presente estudo, foi efetuada uma análise das plataformas que permitem uma navegação anónima e segura e um estudo das tecnologias e programas com potencial de violação de privacidade e intrusão informática usados por nações de grande notoriedade. Este trabalho teve como objetivo principal analisar as tecnologias de monitorização e de vigilância informática identificando as tecnologias disponíveis, procurando encontrar potenciais soluções no sentido de investigar a possibilidade de desenvolver e disponibilizar uma ferramenta multimédia alicerçada em Linux e em LiveDVD (Sistema Operativo Linux que corre a partir do DVD sem necessidade de instalação). Foram integrados recursos no protótipo com o intuito de proporcionar ao utilizador uma forma ágil e leiga para navegar na Web de forma segura e anónima, a partir de um sistema operativo (SO) virtualizado e previamente ajustado para o âmbito anteriormente descrito. O protótipo foi testado e avaliado por um conjunto de cidadãos no sentido de aferir o seu potencial. Termina-se o documento com as conclusões e o trabalho a desenvolver futuramente.

Internationalization of Papo D’anjo to Mexico

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics

Geospatial assessment of pest-induced forest damage through the use of UAV-bases NIR imaging and Gi-technology

Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.

Haida Totem Poles: Reflections of a Society

The Haida were a First Nations group located on the Northwest Coast of Canada. They were exceptional wood carvers that produced various types of works, the most monumental of which were their totem poles. This dissertation analyses 26 of these open architectural structures, each of which belonged to one of the following five types: frontal, mortuary, memorial, house post, or corner post. Of the representations found on poles, 28 different figures were identified. However, individual poles were found to contain between one and fourteen different figures with frontal poles generally featuring the most. The predominant figures on the inventoried poles proved to be birds, humans, and bears. An iconographic structure of a tripartite character was detected that reflects the religious ideology of the Haida population with birds being featured at the top of the poles, humans in the middle, and bears at the lowest point. It also suggests the possible transition from a hunter-gatherer economy to a food producing economy.***********************************************************************************Os Haida foram um grupo das Primeiras Nações que habitaram a costa Noroeste do Canadá. Eram excepcionais escultores de madeira, tendo produzido variados tipos de artefactos, dos quais os totem poles eram os mais monumentais. Na presente dissertação são analisadas 26 dessas estruturas arquitectónicas de exterior, sendo que cada uma delas pertenceria a um dos seguintes cinco tipos: frontal, funerário, memorial, travemestra, ou postes de esquina. Das representações encontradas nos postes, foram individualizadas 28 figuras. No entanto, em postes isolados foi possível identificar entre uma e catorze figuras distintas, sendo os postes frontais os que apresentavam, geralmente, o maior número. A análise destes postes permitiu detectar uma estrutura iconográfica tripartida que reflectia a ideologia religiosa das populações Haida, representando-se as aves no topo, os humanos a meio, e os ursos na base dos postes. Por outro lado, foi possível sugerir, para estas populações, a transição de uma economia baseada na caça-recolecção para uma economia de produção alimentar.

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.

Hand gesture recognition for human computer interaction : a comparative study of different image features

Hand gesture recognition for human computer interaction, being a natural way of human computer interaction, is an area of active research in computer vision and machine learning. This is an area with many different possible applications, giving users a simpler and more natural way to communicate with robots/systems interfaces, without the need for extra devices. So, the primary goal of gesture recognition research is to create systems, which can identify specific human gestures and use them to convey information or for device control. For that, vision-based hand gesture interfaces require fast and extremely robust hand detection, and gesture recognition in real time. In this study we try to identify hand features that, isolated, respond better in various situations in human-computer interaction. The extracted features are used to train a set of classifiers with the help of RapidMiner in order to find the best learner. A dataset with our own gesture vocabulary consisted of 10 gestures, recorded from 20 users was created for later processing. Experimental results show that the radial signature and the centroid distance are the features that when used separately obtain better results, with an accuracy of 91% and 90,1% respectively obtained with a Neural Network classifier. These to methods have also the advantage of being simple in terms of computational complexity, which make them good candidates for real-time hand gesture recognition.

Slip flows of Newtonian and viscoelastic fluids in a 4:1 contraction

This work presents a numerical study of the 4:1 planar contraction flow of a viscoelastic fluid described by the simplified Phan-Thien–Tanner model under the influence of slip boundary conditions at the channel walls. The linear Navier slip law was considered with the dimensionless slip coefficient varying in the range ½0; 4500. The simulations were carried out for a small constant Reynolds number of 0.04 and Deborah numbers (De) varying between 0 and 5. Convergence could not be achieved for higher values of the Deborah number, especially for large values of the slip coefficient, due to the large stress gradients near the singularity of the reentrant corner. Increasing the slip coefficient leads to the formation of two vortices, a corner and a lip vortex. The lip vortex grows with increasing slip until it absorbs the corner vortex, creating a single large vortex that continues to increase in size and intensity. In the range De = 3–5 no lip vortex was formed. The flow is characterized in detail for De ¼ 1 as function of the slip coefficient, while for the remaining De only the main features are shown for specific values of the slip coefficient.

Sistema inteligente para análise do posicionamento de árbitros de futebol

Dissertação de mestrado em Sistemas de Informação

vertex effect in polycrystalline materials : simulation, a macroscopic model, and structural application

Polycrystal Plasticity, Yield-Vertex, Corner, Vertex-Effect, Microscale, Macroscale, Multiaxial, Torsional Buckling, Cruciform Column