The potential field method and the nonlinear attractor dynamics approach: what are the differences?

One of the most popular approaches to path planning and control is the potential field method. This method is particularly attractive because it is suitable for on-line feedback control. In this approach the gradient of a potential field is used to generate the robot's trajectory. Thus, the path is generated by the transient solutions of a dynamical system. On the other hand, in the nonlinear attractor dynamic approach the path is generated by a sequence of attractor solutions. This way the transient solutions of the potential field method are replaced by a sequence of attractor solutions (i.e., asymptotically stable states) of a dynamical system. We discuss at a theoretical level some of the main differences of these two approaches.

Vision-based hand Wheel-chair control

Several studies have shown that people with disabilities benefit substantially from access to a means of independent mobility and assistive technology. Researchers are using technology originally developed for mobile robots to create easier to use wheelchairs. With this kind of technology people with disabilities can gain a degree of independence in performing daily life activities. In this work a computer vision system is presented, able to drive a wheelchair with a minimum number of finger commands. The user hand is detected and segmented with the use of a kinect camera, and fingertips are extracted from depth information, and used as wheelchair commands.

RoboCup Soccer Leagues

RoboCup was created in 1996 by a group of Japanese, American, and European Artificial Intelligence and Robotics researchers with a formidable, visionary long-term challenge: “By 2050 a team of robot soccer players will beat the human World Cup champion team.” At that time, in the mid 90s, when there were very few effective mobile robots and the Honda P2 humanoid robot was presented to a stunning public for the first time also in 1996, the RoboCup challenge, set as an adversarial game between teams of autonomous robots, was fascinating and exciting. RoboCup enthusiastically and concretely introduced three robot soccer leagues, namely “Simulation,” “Small-Size,” and “Middle-Size,” as we explain below, and organized its first competitions at IJCAI’97 in Nagoya with a surprising number of 100 participants [RC97]. It was the beginning of what became a continously growing research community. RoboCup established itself as a structured organization (the RoboCup Federation www.RoboCup.org). RoboCup fosters annual competition events, where the scientific challenges faced by the researchers are addressed in a setting that is attractive also to the general public. and the RoboCup events are the ones most popular and attended in the research fields of AI and Robotics.RoboCup further includes a technical symposium with contributions relevant to the RoboCup competitions and beyond to the general AI and robotics.

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.

Hand gesture recognition system based in computer vision and machine learning

"Lecture notes in computational vision and biomechanics series, ISSN 2212-9391, vol. 19"

Tecnologias da informação e comunicação na formação continuada de professores: estudode caso em escolas do Brasil e Portugal com recursos e aplicação do Google+

Tese de Doutoramento em Ciências da Educação (área de especialização em Tecnologia Educativa)

Monitoring energy consumption in android applications

Dissertação de Mestrado em Engenharia Informática

Radiação solar e distribuição vertical de área foliar em floresta - Reserva Biológica do Cuieiras ZF2, Manaus

Neste estudo, a distribuição vertical de área foliar em floresta é investigada em conexão com o regime de radiação, usando as medidas de radiação solar realizadas no período de julho a novembro de 2001, na Reserva Biológica do Cuieiras - Manaus ZF2, km 14 e km 34, na Amazônia Central. Técnicas experimentais de amostragem de radiação no interior de coberturas vegetais de grande porte são utilizadas, com dispositivos de suporte móveis constituídos por reticulados modulares, que permitem a disposição dos sensores de radiação em diferentes níveis de uma mesma vertical no interior da cobertura. Inversão de modelos radiativos em coberturas vegetais densas permite as análises sobre a distribuição vertical de área foliar. A variabilidade espacial de área foliar (IAF, função a(z)) é estabelecida para os dois sítios experimentais a partir de medidas de radiação solar, individualizadas em três verticais em cada um desses locais. O índice de área foliar total médio (IAF) da vegetação local para o sítio experimental do km 14 alcançou o valor de 6,4 e para o sítio experimental do km 34 o valor de 6,1. Uma análise comparativa é desenvolvida sobre distribuições verticais de área foliar obtidas em sítios experimentais da Amazônia, usando o mesmo sistema de medidas de radiação solar.

Learning Robotics for youngsters - the RoboParty experience

Series: "Advances in intelligent systems and computing , ISSN 2194-5357, vol. 417"

Off-line simulation inspires insight: a neurodynamics approach to efficient robot task learning

There is currently an increasing demand for robots able to acquire the sequential organization of tasks from social learning interactions with ordinary people. Interactive learning-by-demonstration and communication is a promising research topic in current robotics research. However, the efficient acquisition of generalized task representations that allow the robot to adapt to different users and contexts is a major challenge. In this paper, we present a dynamic neural field (DNF) model that is inspired by the hypothesis that the nervous system uses the off-line re-activation of initial memory traces to incrementally incorporate new information into structured knowledge. To achieve this, the model combines fast activation-based learning to robustly represent sequential information from single task demonstrations with slower, weight-based learning during internal simulations to establish longer-term associations between neural populations representing individual subtasks. The efficiency of the learning process is tested in an assembly paradigm in which the humanoid robot ARoS learns to construct a toy vehicle from its parts. User demonstrations with different serial orders together with the correction of initial prediction errors allow the robot to acquire generalized task knowledge about possible serial orders and the longer term dependencies between subgoals in very few social learning interactions. This success is shown in a joint action scenario in which ARoS uses the newly acquired assembly plan to construct the toy together with a human partner.

Review of robotic technology for keyhole transcranial stereotactic neurosurgery

The research of stereotactic apparatus to guide surgical devices began in 1908, yet a major part of today's stereotactic neurosurgeries still rely on stereotactic frames developed almost half a century ago. Robots excel at handling spatial information, and are, thus, obvious candidates in the guidance of instrumentation along precisely planned trajectories. In this review, we introduce the concept of stereotaxy and describe a standard stereotactic neurosurgery. Neurosurgeons' expectations and demands regarding the role of robots as assistive tools are also addressed. We list the most successful robotic systems developed specifically for or capable of executing stereotactic neurosurgery. A critical review is presented for each robotic system, emphasizing the differences between them and detailing positive features and drawbacks. An analysis of the listed robotic system features is also undertaken, in the context of robotic application in stereotactic neurosurgery. Finally, we discuss the current perspective, and future directions of a robotic technology in this field. All robotic systems follow a very similar and structured workflow despite the technical differences that set them apart. No system unequivocally stands out as an absolute best. The trend of technological progress is pointing toward the development of miniaturized cost-effective solutions with more intuitive interfaces.

Método QFD como Ferramenta para Desenvolvimento Conceitual de Produtos de Madeiras da Amazônia

O setor moveleiro caracteriza-se como um segmento que oferta produtos de diferentes formas e matérias-primas e estes produtos precisam ter diferenciais para se destacar e atrair o interesse do consumidor. Em Manaus, o comércio de moveis encontra-se num estágio considerado em evolução, podendo notar nos produtos ofertados, a total ausência de características que despertem o interesse de compra nos consumidores. Seguindo este contexto, este artigo tem como objetivo apresentar preferências em termos de produtos de madeiras da Amazônia dos consumidores de três classes econômicas - A1, B2 e C residentes na cidade de Manaus e a aplicação da primeira matriz (casa da qualidade) do método QFD para definição dos conceitos dos produtos identificados como preferidos pelas classes econômicas analisadas. Os resultados revelaram que há pouca variação nas preferências por tipos de produtos por classe econômica, propondo-se conceitualmente que os produtos incorporem os atributos tidos como preferidos por cada uma das classes econômicas analisada. Conclusões importantes: bom acabamento; design - estilo contemporâneo; preferência por madeira maciça e não por painéis (MDF).

Reconfiguração e novas funcionalidades para um servidor REST ONVIF: serviço de IO e configuração de descoberta

Dissertação de mestrado em Engenharia de Telecomunicações e Informática

Mobilidade da rádio na era digital: interatividade, participação e partilha de conteúdos nas emissoras ibéricas

No quadro da investigação científica sobre rádio, os últimos anos têm dado a conhecer inúmeras abordagens sobre o significado de uma post-radio (Oliveira & Portela, 2011), isto é, a definição de um conjunto de questões que se colocam à inclusão da rádio contemporânea em ambientes digitais e online. Esta migração digital tem vindo a proporcionar o desenvolvimento das aplicações móveis das rádios, como o alargamento das potencialidades comunicativas (Aguado, Feijoo & Martínez, 2013), de audiências, de convergência de conteúdos interativos entre ouvintes-utilizadores. Conscientes desta oportunidade, as principais emissoras da Espanha e Portugal alargaram o universo da radiofonia à plataforma móvel, com especial atenção aos telefones inteligentes, através do desenvolvimento de aplicações móveis (apps) (Cerezo, 2010). Os smartphones, como símbolo de uma cultura em permanente mutação, sugerem não apenas uma maior facilidade no acesso e interação, mas acrescentam grandes possibilidades para a difusão de conteúdos entre audiências, o que estudos têm designado por user distributed content (Villi, 2012). O presente artigo apresenta uma análise exploratória sobre as políticas atuais das principais rádios espanholas e portuguesas nas aplicações móveis, avaliando o grau de interação e participação mobilizado nessas plataformas. Durante a observação, conclui-se, entre outros dados, que a plataforma móvel representa um canal suplementar para a rádio tradicional FM, mais que um novo meio com linguagem e expressividade próprios.

O impacto da inclusão do dador na avaliação ergonómica dos locais de colheita de sangue

Dissertação de mestrado em Engenharia Humana