Browsing by Issue Date, starting with "2015-06"
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- Curvas geodésicas : um exemplo com resolução analíticaPublication . Fatelo, J. P.; Martins-Ferreira, N.Apresentamos um exemplo de uma superfície não trivial em R3 na qual as curvas geodésicas são encontradas analiticamente.
- Assistive Mobile Applications for DyslexiaPublication . Madeira, Jorge; Silva, Catarina; Ferreira, Paula Cristina; Marcelino, LuísThe ability to read is one of the main skills of a human being. However, some of us have reading difficulties, regardless of social status, level of intelligence or education. This disorder is the main characteristic of dyslexia and is maintained throughout life,requiring early and specialized intervention. Dyslexia is defined as a learning disturbance in the area of reading, writing and spelling. Although the numbers of prevalence rely heavily on the type of investigation conducted, several studies indicate that up to 17% of the world population is dyslexic, and that men have greater prevalence. In this work we will address the use of assistive mobile applications for dyslexia by analyzing possible solutions and proposing a prototype of a mobile application that can be used by dyslexic and whilst giving feedback both to the dyslexic him/herself and to the assisting technician or teacher. The implemented prototype focuses the Portuguese language and was tested with Portuguese students with ages between 10 and 12 years old. Preliminary results show that the proposed gamified set of activities, allow dyslexics to improve multisensory perception, constituting an added value facilitator of adaptiveness and learning.
- Accuracy versus complexity of MARG-based filters for remote control pointing devicesPublication . Rasteiro, Miguel ; Costelha, Hugo; Conde Bento, Luis; Assunção, PedroAlthough most current pointing devices rely on relative rotation increments, absolute orientation allows for a more intuitive interaction. However, this is difficult to implement in low-energy consumption devices since accurate fusion filters are computationally intensive. This work presents a comparative study of low-complexity filters and state-of-the-art orientation tracking systems, enabling to access complexity versus portability. A relevant set of different MARG units currently available on the market were studied under systematic tests and human subjective user analysis. Experimental results show that it is possible to obtain similar accuracy using low-complexity filters to the ones observed with state-of-the-art orientation tracking systems. © 2015 IEEE.
- Computer construction of platonic solidsPublication . Gaspar, M.; Leita, M.; Martins-Ferreira, N.; Panda, B. N.In this paper we develop a novel method to generate a 3D geometrical model from 2D planer images. As an example of application, we construct 3D models of each one of the five platonic solids from their platonic graphs.
- Computer tool for maximizing the placement of congruent polyhedraPublication . Gaspar, M.; Alves, N.; Mateus, A.; Martins-Ferreira, N.Given multiple identical polyhedral objects and a parallelepiped container, how should one place the objects so that the largest number fits inside the container? This simple question is important in many applications, yet the answer is elusive. In fact, we know of no published solution for this very general formulation. Still, in many circumstances, further restrictions apply, resulting in a large number of variations requiring different algorithmic strategies. This paper is the continuation of [12] and focus on the fundamental concepts and tools that are used for this kind of problem, such as the no-fit polygon. We also present some of its many variations, giving in particular one that applies to the stereolithographic rapid prototyping technology.
- Modelação do pêndulo caótico : parte 1Publication . Baptista, Diogo Nascimento; Baptista, Alexandra Nascimento; Costelha, HugoUm pêndulo físico, sujeito a um amortecimento e a uma força externa que atua sobre o eixo de rotação deste, reproduz vários tipo de movimentos, que poderão ser periódicos ou não. Controlando a amplitude e a frequência da força externa, o objetivo é prever e caracterizar o tipo de movimentos descritos pelo pêndulo. Neste primeiro trabalho sobre o tema, serão introduzidas as equações necessárias para a modulação do movimento e analizados os dados experimentais resultantes das leituras efetuadas num pêndulo cujo eixo de rotação está sujeito a um movimento horizontal periódico.
- OER, Open Access and Scholarship in Portuguese Higher EducationPublication . Cardoso, Paula; Morgado, Lina; Teixeira, AntónioThe present paper is part of a PhD research, which is being developed in the scope of the Doctoral Programme in Education, specialisation in Distance Education and eLearning at Universidade Aberta, the Portuguese Open University. The theoretical framework for the research is Open Education, particularly the specific fields of Open Educational Resources (OER) and Open Access (OA). The main objective of the research is to identify and understand the awareness, knowledge and attitudes of scholars in Portuguese public Higher Education Institutions (HEI), regarding OER and OA and, in particular, to compare scholars’ awareness, attitudes and perceptions towards OER and OA in the context of their teaching and research practices. This will also allow us to represent the Portuguese reality and, consequently, position the Portuguese public higher education practices within the global panorama and also may be able to inform future decisions, whether institutionally, governmentally or even within a broader perspective. The current paper intends to present the research project and also to reflect the literature review carried out so far, in order to contextualise the research problem and also to describe the methodological procedures defined for the study.
- Sistema de aquisição e registo de sinais biomédicos baseado numa plataforma de desenvolvimento open-source de baixo custoPublication . Jardan, Daniel; Gil, João; Martins, Fernando; Ferreira, Lino; Fonseca-Pinto, RuiEste artigo apresenta um sistema de aquisição e registo de sinais biomédicos baseado na plataforma desenvolvimento open-source Arduino. O sistema tem associado um cartão de memória para registo de dados, bem como um acelerómetro que indica a atividade/postura do paciente. É utilizado um módulo de comunicação Blue- tooth para ligação a um dispositivo móvel (smartphone e tablet) de forma a permitir a parametrização, o comando do sistema de aquisição e a monitorização em tempo real dos dados adquiridos. Estes dados foram usados para calcular o balanço vago-simpático associado a tarefas específicas do dia-a-dia.
- ETL^2 - Educational tool for learning ETLPublication . Oliveira, Rui; Ramos, JoseIn Data Warehouse environments, the core Extract-Transform-Load (ETL) process is the most technically complex and sensitive of all: promoting its effective learning to undergraduate students is therefore a serious challenge. Despite today's industrial widespread use of ETL graphical tools, these do not comply with the needs of ETL teaching given their usage complexity and high abstraction level. Moreover, no educational tools exist focused on assisting ETL teaching. For that purpose, the paper presents an innovative educational tool. The tool's basic yet powerful features allow students to easily test concepts and also to build real-world Data Warehouse prototypes in a fast and simple fashion keeping focus on the product conceptualization without severely abstracting themselves from the background mechanisms of the ETL process. The tool has evolved in the past five years in the Decision Support Systems course of the Informatics Engineering undergraduate degree at the Polytechnic Institute of Leiria. © 2015 IEEE.
- Characterization of antiproliferative potential and biological targets of a copper compound containing 4′-phenyl terpyridinePublication . Mendo, Ana Soraia; Figueiredo, Sara; Roma-Rodrigues, Catarina; Videira, Paula A.; Ma, Zhen; Diniz, Mário; Larguinho, Miguel; Costa, Pedro M.; Lima, João C.; Pombeiro, Armando J. L.; Baptista, Pedro V.; Fernandes, Alexandra R.Several copper complexes have been assessed as anti-tumor agents against cancer cells. In this work, a copper compound [Cu(H2O){OS(CH3)2}L](NO3)2 incorporating the ligand 4′-phenyl-terpyridine antiproliferative activity against human colorectal, hepatocellular carcinomas and breast adenocarcinoma cell lines was determined, demonstrating high cytotoxicity. The compound is able to induce apoptosis and a slight delay in cancer cell cycle progression, probably by its interaction with DNA and induction of double-strand pDNA cleavage, which is enhanced by oxidative mechanisms. Moreover, proteomic studies indicate that the compound induces alterations in proteins involved in cytoskeleton maintenance, cell cycle progression and apoptosis, corroborating its antiproliferative potential.