Connectivity-Enforcing Hough Transform for the Robust Extraction of Line Segments

Global voting schemes based on the Hough transform (HT) have been widely used to robustly detect lines in images. However, since the votes do not take line connectivity into account, these methods do not deal well with cluttered images. In opposition, the so-called local methods enforce connectivity but lack robustness to deal with challenging situations that occur in many realistic scenarios, e.g., when line segments cross or when long segments are corrupted. In this paper, we address the critical limitations of the HT as a line segment extractor by incorporating connectivity in the voting process. This is done by only accounting for the contributions of edge points lying in increasingly larger neighborhoods and whose position and directional content agree with potential line segments. As a result, our method, which we call STRAIGHT (Segment exTRAction by connectivity-enforcInG HT), extracts the longest connected segments in each location of the image, thus also integrating into the HT voting process the usually separate step of individual segment extraction. The usage of the Hough space mapping and a corresponding hierarchical implementation make our approach computationally feasible. We present experiments that illustrate, with synthetic and real images, how STRAIGHT succeeds in extracting complete segments in several situations where current methods fail.Comment: Submitted for publicatio

How does knowledge affect the internationalization process of a company in a new market ?

This dissertation analyzes the influence of knowledge in the internationalization process of a company, focusing on the range of existing knowledge and its impact on the different stages of internationalization. The study includes three interviews to a top manager working for COBA since 1993. Knowledge can derive either from education or experience. Findings show that a proper usage of the different types of knowledge is fundamental to reach success during internationalization, with special concerns regarding the company’s lifetime when starting internationalization, and the industry involved. Moreover, the implementation phase of the internationalization process is the one where the influence of knowledge is more felt. The clash with reality can highlight existent flaws of previous decisions made; being crucial the impact of knowledge to enrich the turnaround capacity demanded for a company to re-adapt strategies. The retention of knowledge is considered crucial to preserve the major internal competences, specially leading to competitive advantages when facing external markets, with higher internal levels of uncertainty. Regarding the relation of COBA with the topic addressed in this dissertation, the main conclusion demonstrates a lack of internal awareness about the impact of knowledge in the internationalization process, despite its occurrence. The final goal is to reach findings appealing for future literature, as well as to create the awareness of organizations about this reality, leading to a better usage of the different types of knowledge during all the phases of internationalization

Cooperative Platooning and Servicing for Spacecraft Formation Flying using Model Predictive Control

This work was partially funded by FCT project REPLACE (PTDC/EEIAUT/32107/2017) which includes Lisboa 2020 and PIDDAC funds, project CAPTURE (PTDC/EEIAUT/1732/2020).This paper addresses two complementary problems of spacecraft formation flying, namely spacecraft platooning and on-orbit spacecraft servicing, using Model Predictive Control (MPC). With the proposed solutions, these space formation scenarios can be regarded as a cooperative system composed of several spacecraft with a common goal, which may have clear advantages relative to other approaches. For each application scenario, a different optimization problem and MPC design is presented, including relevant constraints to deal with physical limitations, visibility problems, and also to guarantee a collision-free trajectory from other spacecraft or obstacles. The proposed methods are validated with realistic simulation results, showing that all vehicles demonstrate reliable performance following a given trajectory or goal in a formation, while satisfying all the considered constraints.publishersversionpublishe

Does work per repetition and phase angle play a role in Sarcopenia?

Aging is related to the increase of several chronic diseases, such as, osteoarthritis, osteoporosis, diabetes, hypertension and sarcopenia. Sarcopenia (progressive loss of muscle mass and physical performance) is related to difficulties in treating other comorbidities, whether pharmacologically or non-pharmacologically.info:eu-repo/semantics/publishedVersio

History, Nation and Politics: the Middle Ages in Modern Portugal (1890-1947)

Nas últimas décadas, o estudo da historiografia, da memória histórica e dos usos do passado tem suscitado cada vez maior atenção junto dos meios académicos. O medievalismo em particular, comummente entendido como a representação ou o uso da Idade Média no período pós-medieval, assume aqui um papel significativo, dada a importância da época medieval na cultura histórica romântica e nos processos de construção das identidades nacionais desde o século XIX. No contexto académico português, porém, o medievalismo foi ainda escassamente analisado, faltando um estudo que abranja as suas várias dimensões, da historiografia às políticas de memória. Esta dissertação pretende colmatar esta lacuna, ao explorar as várias representações da Idade Média em Portugal entre o final do século XIX e a primeira metade do século XX. Focando três grandes temas – escrita da história, património artístico e comemorações históricas – iremos demonstrar como certos conceitos, instituições, figuras, eventos e obras da história medieval portuguesa foram narrados, retrabalhados e celebrados, à luz dos discursos decadentistas sobre a nação e sobre o mundo ocidental e da evolução política do país neste período. Estudos internacionais sobre este tema permitirão a realização de exercícios comparativos, bem como considerar a dimensão transnacional do medievalismo português, inserido nas grandes correntes culturais e ideologias políticas que influenciaram as várias representações da época medieval neste período. No final, iremos verificar como uma visão essencialmente romântica da história portuguesa persistiu ao longo de grande parte do século XX, ao representar dicotomicamente a Idade Média de forma positiva em comparação com uma Modernidade identificada com declínio civilizacional e espiritual.In recent decades, the study of historiography, historical memory and the uses of the past has become a subject of increasing attention in academic circles. Medievalism in particular, commonly understood as the representation or use of the Middle Ages in the post-medieval period, assumes here an significant role, given the importance of the medieval epoch in Romantic historical culture and in nation-building processes since the nineteenth century. However, medievalism has still been scarcely analysed in the Portuguese context, lacking a study that encompasses its multiple dimensions, from historiography to politics of memory. This dissertation aims to fulfil this gap, by exploring the various representations of the Middle Ages in Portugal between the late nineteenth and the first half of the twentieth century. Focusing on three major topics – writing of history, artistic heritage and historical commemorations –, we will demonstrate how certain concepts, institutions, figures, events and works of Portuguese medieval history were narrated, reworked and celebrated, in the light of decadentist discourses about the nation and the Western world and of Portugal‘s political evolution in this period. International research on the topic will allow the making of comparative analyses and the understanding of the transnational dimension of Portuguese medievalism, inserted in the major cultural trends and political ideologies that influenced the various depictions of the medieval epoch in this period. In the end, we will show that an essentially Romantic view of Portuguese history persisted through the twentieth century, dichotomically presenting the Middle Ages in a positive light in comparison with a Modernity identified with civilizational and spiritual decline

Visual programming in a heterogeneous multi-core environment

É do conhecimento geral de que, hoje em dia, a tecnologia evolui rapidamente. São criadas novas arquitecturas para resolver determinadas limitações ou problemas. Por vezes, essa evolução é pacífica e não requer necessidade de adaptação e, por outras, essa evolução pode Implicar mudanças. As linguagens de programação são, desde sempre, o principal elo de comunicação entre o programador e o computador. Novas linguagens continuam a aparecer e outras estão sempre em desenvolvimento para se adaptarem a novos conceitos e paradigmas. Isto requer um esforço extra para o programador, que tem de estar sempre atento a estas mudanças. A Programação Visual pode ser uma solução para este problema. Exprimir funções como módulos que recebem determinado Input e retomam determinado output poderá ajudar os programadores espalhados pelo mundo, através da possibilidade de lhes dar uma margem para se abstraírem de pormenores de baixo nível relacionados com uma arquitectura específica. Esta tese não só mostra como combinar as capacidades do CeII/B.E. (que tem uma arquitectura multi­processador heterogénea) com o OpenDX (que tem um ambiente de programação visual), como também demonstra que tal pode ser feito sem grande perda de performance. ABSTRACT; lt is known that nowadays technology develops really fast. New architectures are created ln order to provide new solutions for different technology limitations and problems. Sometimes, this evolution is pacific and there is no need to adapt to new technologies, but things also may require a change every once ln a while. Programming languages have always been the communication bridge between the programmer and the computer. New ones keep coming and other ones keep improving ln order to adapt to new concepts and paradigms. This requires an extra-effort for the programmer, who always needs to be aware of these changes. Visual Programming may be a solution to this problem. Expressing functions as module boxes which receive determined Input and return determined output may help programmers across the world by giving them the possibility to abstract from specific low-level hardware issues. This thesis not only shows how the CeII/B.E. (which has a heterogeneous multi-core architecture) capabilities can be combined with OpenDX (which has a visual programming environment), but also demonstrates that lt can be done without losing much performance

Phase angle in osteoarthritis patients, relations with pain, muscular mass and strength

Several researches have been carried out to see the relation between the Phase Angle (PhA), disease and several health risks factors. Ageing is associated with the loss of muscle mass and changes in body composition, which result in a decrease of the PhA. Malnutrition and inflammation have been reported to have a strong influence on PhA in diseased individuals. Subjects with Osteoarthritis (OA) have decreased muscular strength and pain. The aim of this study was to understand if the PhA was altered in patients with OA and if it's related with pain, muscular mass and strength.info:eu-repo/semantics/publishedVersio

Modelo de computación evolutivo para redes sostenibles, eficientes y resistentes.

We present a new approach to adapt the differential evolution (DE) algorithm so that it can be applied in combinatorial optimization problems. The differential evolution algorithm has been proposed as an optimization algorithm for the continuous domain, using real numbers to encode the solutions, and its main operator, the mutation, uses a arithmetic operations to create a mutant using three different random solutions. This mutation operator cannot be used in combinatorial optimization problems, which have a domain of a discrete and finite set of objects. Based on this concept, we present an idea of representing each solution as a set, and replace the arithmetic operators in the classic DE genetic operators by set operators. Using a well known NP-hard problem, the traveling salesman problem (TSP), as an example of a combinatorial optimization problem, we study different possibilities for the mutation operator, presenting the advantages and disadvantages of each, before setting with the best one. We also explain the modifications made to adapt the algorithm for a multiobjective optimization algorithm. Some of these modifications are inherent to the different type of problems, other modification are proposed to improve the algorithm. Amongst the later modification are using more than one population in the evolution process. We also present a new self-adaptive variation of the multiobjective optimization algorithm, although this is not limited to the multi-objective case, and can be used also in the single-objective

Simulation of biologically inspired object movement for the study of object tracking algorithms

Major advances in Cell and Molecular Biology have been associated with the advances in live-cell microscopy imaging, and these studies started to rely on temporal single cell imaging. To support these efforts, available automated image analysis methods such as cell segmentation and cell tracking during a time-series analysis should be improved. One important step is the validation of such image processing methods. Ideally, the “ground truth” should be known, which is possible only by manually labelling images or by artificially produced images. To simulate such artificial images we developed a platform that can simulate biologically inspired objects, by generating bodies with different morphologies, physical movement and that can aggregate in clusters. Using this platform, we tested and compared four tracking algorithms: Simple Nearest-Neighbour (NN), NN with Morphology and two DBSCAN based ones. In this work we showed that Simple NN work for small object velocities, while the other algorithms perform better on higher velocities and when clustered. This platform can generate new benchmark images and is openly available to test other tracking algorithms. (http://griduni.uninova.pt/Clustergen/ClusterGen_v1.0.zip