Um novo gerador central de padrões de locomoção para geração de trajectórias em tempo real de robôs quadrúpedes

Neste trabalho estuda-se a geração de trajectórias em tempo real de um robô quadrúpede. As trajectórias podem dividir-se em duas componentes: rítmica e discreta. A componente rítmica das trajectórias é modelada por uma rede de oito osciladores acoplados, com simetria 4 2 Z  Z . Cada oscilador é modelado matematicamente por um sistema de Equações Diferenciais Ordinárias. A referida rede foi proposta por Golubitsky, Stewart, Buono e Collins (1999, 2000), para gerar os passos locomotores de animais quadrúpedes. O trabalho constitui a primeira aplicação desta rede à geração de trajectórias de robôs quadrúpedes. A derivação deste modelo baseia-se na biologia, onde se crê que Geradores Centrais de Padrões de locomoção (CPGs), constituídos por redes neuronais, geram os ritmos associados aos passos locomotores dos animais. O modelo proposto gera soluções periódicas identificadas com os padrões locomotores quadrúpedes, como o andar, o saltar, o galopar, entre outros. A componente discreta das trajectórias dos robôs usa-se para ajustar a parte rítmica das trajectórias. Este tipo de abordagem é útil no controlo da locomoção em terrenos irregulares, em locomoção guiada (por exemplo, mover as pernas enquanto desempenha tarefas discretas para colocar as pernas em localizações específicas) e em percussão. Simulou-se numericamente o modelo de CPG usando o oscilador de Hopf para modelar a parte rítmica do movimento e um modelo inspirado no modelo VITE para modelar a parte discreta do movimento. Variou-se o parâmetro g e mediram-se a amplitude e a frequência das soluções periódicas identificadas com o passo locomotor quadrúpede Trot, para variação deste parâmetro. A parte discreta foi inserida na parte rítmica de duas formas distintas: (a) como um offset, (b) somada às equações que geram a parte rítmica. Os resultados obtidos para o caso (a), revelam que a amplitude e a frequência se mantêm constantes em função de g. Os resultados obtidos para o caso (b) revelam que a amplitude e a frequência aumentam até um determinado valor de g e depois diminuem à medida que o g aumenta, numa curva quase sinusoidal. A variação da amplitude das soluções periódicas traduz-se numa variação directamente proporcional na extensão do movimento do robô. A velocidade da locomoção do robô varia com a frequência das soluções periódicas, que são identificadas com passos locomotores quadrúpedes.

Autodano e ideação suicida na população estudantil da Universidade dos Açores

Dissertação de Mestrado, Psicologia da Educação, especialidade em Contextos Educativos, 15 de Março de 2016, Universidade dos Açores.

Negotiation platform for personalised advertising

This paper describes a multi-agent brokerage platform for near real time advertising personalisation organised in three layers: user interface, agency and marketplace. The personalisation is based on the classification of viewer profiles and advertisements (ads). The goal is to provide viewers with a personalised advertising alignment during programme intervals. The enterprise interface agents upload new ads and negotiation profiles to producer agents and new user and negotiation profiles to distributor agents. The agency layer is composed of agents that represent ad producer and media distributor enterprises as well as the market regulator. The enterprise agents offer data upload and download operations as Web Services and register the specification of these interfaces at an UDDI registry for future discovery. The market agent supports the registration and deregistration of enterprise delegate agents at the marketplace. This paper addresses the marketplace layer, an agent-based negotiation platform per se, where delegates of the relevant advertising agencies and programme distributors negotiate to create the advertising alignment that best fits a viewer profile and the advertising campaigns available. The whole brokerage platform is being developed in JADE, a multi-agent development platform. The delegate agents download the negotiation profile and upload the negotiation results from / to the corresponding enterprise agent. In the meanwhile, they negotiate using the Iterated Contract Net protocol. All tools and technologies used are open source.

A proposal for media component brokerage

This paper describes how MPEG-4 object based video (obv) can be used to allow selected objects to be inserted into the play-out stream to a specific user based on a profile derived for that user. The application scenario described here is for personalized product placement, and considers the value of this application in the current and evolving commercial media distribution market given the huge emphasis media distributors are currently placing on targeted advertising. This level of application of video content requires a sophisticated content description and metadata system (e.g., MPEG-7). The scenario considers the requirement for global libraries to provide the objects to be inserted into the streams. The paper then considers the commercial trading of objects between the libraries, video service providers, advertising agencies and other parties involved in the service. Consequently a brokerage of video objects is proposed based on negotiation and trading using intelligent agents representing the various parties. The proposed Media Brokerage Platform is a multi-agent system structured in two layers. In the top layer, there is a collection of coarse grain agents representing the real world players – the providers and deliverers of media contents and the market regulator profiler – and, in the bottom layer, there is a set of finer grain agents constituting the marketplace – the delegate agents and the market agent. For knowledge representation (domain, strategic and negotiation protocols) we propose a Semantic Web approach based on ontologies. The media components contents should be represented in MPEG-7 and the metadata describing the objects to be traded should follow a specific ontology. The top layer content providers and deliverers are modelled by intelligent autonomous agents that express their will to transact – buy or sell – media components by registering at a service registry. The market regulator profiler creates, according to the selected profile, a market agent, which, in turn, checks the service registry for potential trading partners for a given component and invites them for the marketplace. The subsequent negotiation and actual transaction is performed by delegate agents in accordance with their profiles and the predefined rules of the market.

Fractional central pattern generators for bipedal locomotion

Locomotion has been a major research issue in the last few years. Many models for the locomotion rhythms of quadrupeds, hexapods, bipeds and other animals have been proposed. This study has also been extended to the control of rhythmic movements of adaptive legged robots. In this paper, we consider a fractional version of a central pattern generator (CPG) model for locomotion in bipeds. A fractional derivative D α f(x), with α non-integer, is a generalization of the concept of an integer derivative, where α=1. The integer CPG model has been proposed by Golubitsky, Stewart, Buono and Collins, and studied later by Pinto and Golubitsky. It is a network of four coupled identical oscillators which has dihedral symmetry. We study parameter regions where periodic solutions, identified with legs’ rhythms in bipeds, occur, for 0<α≤1. We find that the amplitude and the period of the periodic solutions, identified with biped rhythms, increase as α varies from near 0 to values close to unity.

Bipedal Locomotion: A Fractional CPG for Generating Patterns

Proceedings of the 10th Conference on Dynamical Systems Theory and Applications

Physical Activity, Obesity Status, and Blood Pressure in Preschool Children

Objective To examine the combined effects of physical activity and weight status on blood pressure (BP) in preschool-aged children. Study design The sample included 733 preschool-aged children (49% female). Physical activity was objectively assessed on 7 consecutive days by accelerometry. Children were categorized as sufficiently active if they met the recommendation of at least 60 minutes daily of moderate-to-vigorous physical activity (MVPA). Body mass index was used to categorize children as nonoverweight or overweight/obese, according to the International Obesity Task Force benchmarks. BP was measured using an automated BP monitor and categorized as elevated or normal using BP percentile-based cut-points for age, sex, and height. Results The prevalence of elevated systolic BP (SBP) and diastolic BP was 7.7% and 3.0%, respectively. The prevalence of overweight/obese was 32%, and about 15% of children did not accomplish the recommended 60 minutes of daily MVPA. After controlling for age and sex, overweight/obese children who did not meet the daily MVPA recommendation were 3 times more likely (OR 3.8; CI 1.6-8.6) to have elevated SBP than nonoverweight children who met the daily MVPA recommendation. Conclusions Overweight or obese preschool-aged children with insufficient levels of MVPA are at significantly greater risk for elevated SBP than their non overweight and sufficiently active counterparts. (J Pediatr 2015;167:98-102).

Step based physical activity guidelines for preschool-aged children

Objective Public health organizations recommend that preschool-aged children accumulate at least 3 h of physical activity (PA) daily. Objective monitoring using pedometers offers an opportunity to measure preschooler's PA and assess compliance with this recommendation. The purpose of this study was to derive step-based recommendations consistent with the 3 h PA recommendation for preschool-aged children. Method The study sample comprised 916 preschool-aged children, aged 3 to 6 years (mean age = 5.0 ± 0.8 years). Children were recruited from kindergartens located in Portugal, between 2009 and 2013. Children wore an ActiGraph GT1M accelerometer that measured PA intensity and steps per day simultaneously over a 7-day monitoring period. Receiver operating characteristic (ROC) curve analysis was used to identify the daily step count threshold associated with meeting the daily 3 hour PA recommendation. Results A significant correlation was observed between minutes of total PA and steps per day (r = 0.76, p < 0.001). The optimal step count for ≥ 3 h of total PA was 9099 steps per day (sensitivity (90%) and specificity (66%)) with area under the ROC curve = 0.86 (95% CI: 0.84 to 0.88). Conclusion Preschool-aged children who accumulate less than 9000 steps per day may be considered Insufficiently Active.

História do Tratamento Cirúrgico do Cancro da Mama - Empirismo e Ciência

A História do tratamento cirúrgico do cancro da mama é bem demonstrativa de que a verdade em Medicina é circunstancial, e que o caminho a percorrer no sentido de a alcançar é árduo. Mostra, também, como ao longo dos séculos o empirismo vai dando lugar ao método científico, e como os estudos prospectivos, controlados e randomizados determinam a alteração dos conceitos e a consequente modificação das técnicas cirúrgicas. Estas vão desde os métodos bárbaros, à luz dos conceitos actuais, que, da Grécia antiga se estendem até à descoberta da anestesia – em que se destacam nomes como Henri de Mondeville, Guy de Chaulliac e Lanfranco na Idade Média, von Hilden e Ambroise Paré no Renascimento, ou H.F. Le Dran, J.L. Petit e Benjamim Bell, no tempo do Iluminismo – até às técnicas cada vez mais meticulosas e racionais, já na Idade Contemporânea, sucessivamente devidas a James Paget, Joseph Pancoast, Charles Moore, William Stewart Halsted, William e Richard Handley, Geoffrey Keynes, Robert McWhirter, George Crile Jr., Cushman Haagensen, Dahl-Iversen, Jerome Urban, David Patey, Bernard Fisher e Umberto Veronesi, entre outros que souberam criar novos paradigmas na História do Tratamento Cirúrgico do Cancro da Mama, para se chegar à prática actual de cirurgia conservadora (mamária e axilar)com reconstrução.

The institutions of archaic post-modernity and their organizational and managerial consequences: The case of Portugal

The long march of modernization of the Western societies tends to be presented as following a regular sequence: societies and institutions were pre-modern, and then they were modernized, eventually becoming post-modern. Such teleology may provide an incomplete or distorted narrative of societal evolution in many parts of the world, even in the ‘post-modern heartland’ of Western Europe, with Portugal being a case in point. The concept of archaic post-modernity has been developed by a philosopher, José Gil, to show how Portuguese institutions and organizations combine elements of pre-modernity and post-modernity. The notion of an archaic post-modernity is advanced in order to provide an alternative account of the modernization process, which enriches discussion of the varieties of capitalism. Differences in historical experiences create singularities that may be considered in the analysis of culture, management and organization.

Structuring for glocalization

Globalization and localization seem to be opposite concepts – a thesis and its antithesis. Nonetheless, managers seem to be able to handle the paradox posed by these two contradicting tensions by enacting, via action, a synthesis that allows for the co-presence of a high level of global integration and local adaptation (instead of a compromise between both), which has been labeled glocalization. We discuss how the concept of improvisation allows this synthesis by developing the two poles that ground it, namely ‘glocal’ strategy and ‘glocal’ organization. Global advantage requires a dialectical capability that organizations rarely achieve, and the importance of which orthodox management theory rarely recognizes.

Predictors of an unsatisfactory response to pentavalent antimony in the treatment of American visceral leishmaniasis

Although treatment of visceral leishmaniasis with pentavalent antimony is usually successful, some patients require second-line drug therapy, most commonly with amphotericin B. To identify the clinical characteristics that predict an inadequate response to pentavalent antimony, a case-control study was undertaken in Teresina, Piaui, Brazil. Over a two-year period, there were 19 cases of VL in which the staff physicians of a hospital prescribed second-line therapy with amphotericin B after determining that treatment with pentavalent antimony had failed. The control group consisted of 97 patients that were successfully treated with pentavalent antimony. A chart review using univariate and multivariate analysis was performed. The cure rate was 90% with amphotericin B. The odds ratio for the prescription of amphotericin B was 10.2 for children less than one year old, compared with individuals aged over 10 years. Patients who presented coinfection had an OR of 7.1 while those on antibiotics had an OR of 2.8. These data support either undertaking a longer course of therapy with pentavalent antimony for children or using amphotericin B as a first-line agent for children and individuals with coinfections. It also suggests that chemoprophylaxis directed toward bacterial coinfection in small children with VL may be indicated.

The role of objects in creative collaborations

Objects matter when professionals collaborate to create new products. Chapter 1 explains the intention of this work, to apply theories on objects in the empirical context of fashion design. Chapter 2 addresses the question of how creative professionals learn about and use strategy tools to turn their artistic fame into a commercial success. For Chapter 3 I collected ethnographic data on the development of a seasonal collection from the idea to the presentation at Fashion Week. The result is a deep insight into the collaborative processes and material objects used when a stable team of designers works with several outside experts. Chapter 4 applies the knowledge of the role of objects in fashion design gained during the ethnography in the context of online co-creation and crowd sourced fashion items. The synthesis of the empirical studies allows me to present the conceptual leap in Chapter 5. In the theoretical essay I review the findings on the role of objects in collaborations in relation to practice theory, present the new concept of the comprehensive object and conclude by stating the possibilities for future research.

Appreciating the power of words and imaginative organizing: A triadic model of ethics practiced in everyday conversations

This thesis provides an alternative framework to analyze power and ethics practiced in everyday conversations, which constitute processes of organizing. Drawing upon narrative frameworks, the analyses of messages posted on an online message board demonstrate people’s imaginative capacity to create relevant stories, in respect of their precise grasp of factual understandings, contextual relevance and evaluative/moral appropriateness, by appropriating others’ words. Based on the empirical analyses, the thesis indicates that studies on power and ethics in organizations can be re-oriented towards appreciating irremediable power imbalances by offering alternative ways of member’s denoting experiences of power.

Alinhamento dos sistemas de informação: o caso de pequenas médias empresas portuguesas no setor vitivinícola português

O estudo dos Sistemas de Informação é particularmente apropriado numa altura em que se assiste a uma “explosão da informação” e da competitividade empresarial. A entrada dos Sistemas de Informação em áreas de negócio para os quais anteriormente não se vislumbrava uma aplicação útil, como o sector Vitivinícola, provou em diversos países ser uma ferramenta essencial para o aumento de produtividade e qualidade dos produtos. O alinhamento do negócio com os Sistemas de Informação, tem sido encarado como um motivo de preocupação pelas organizações, principalmente pelos gestores que reconhecem a importância e benefícios que este alinhamento traz às organizações. Os Sistemas de informação devem ser encarados como sendo a combinação de procedimentos, informação, pessoas e tecnologias organizadas de forma a se poderem concretizar os objetivos de negócio. A presente dissertação tem como objetivo principal discutir o contributo estratégico das Tecnologias e Sistemas de Informação num sector tradicional em Portugal, o sector Vitivinícola. Nesta dissertação apresentam-se os resultados obtidos num estudo sobre o nível de alinhamento dos sistemas de informação com o negócio. Este estudo incidiu sobre as pequenas e médias empresas portuguesas do setor Vitivinícola. Usando como base o modelo de Maturidade de Alinhamento Estratégico desenvolvido por Jerry Luftman, aos resultados obtidos foram avaliados os seis critérios que fazem parte do modelo: Comunicação, Competência/Mensuração do valor, Governança, Parceria, Âmbito e Arquitetura e Competências. Algumas organizações estudadas encontram-se a dar os primeiros passos com o objetivo de alcançar o alinhamento estratégico entre os sistemas de informação e o negócio. No entanto, de haver o reconhecimento das necessidades de alinhamento e da mais-valia que o mesmo possa trazer às organizações, este é ainda deficitário e encontra-se ainda numa fase muito inicial. A maioria das organizações estudadas encara ainda os sistemas de informação como uma despesa e não como uma ferramenta que permitirá um aumento da competitividade e valor da empresa. Espera-se que este paradigma se altere nos próximos anos com a admissão de profissionais com maior formação para os lugares de gestão operacional.