Integration of ROS navigation stack with dynamic environment information in gazebo simulation

Sensing the environment is a crucial task that robots have to perform to navigate autonomously. Furthermore, it must be well executed to make navigation safer and collision- free. As autonomous mobile robots are being deployed in several applications, they often encounter dynamic habitats, where sensing and perceiving the environment becomes harder. This work proposes integrating a wireless sensor network with the Robotic Operating System to incorporate data into layered costmaps used by the robot to navigate, feeding the algorithms with advanced information about the territory. The architecture was tested in simulation, where we could validate the structure and collect data showing improved paths calculated and reduced computational load through better parametrization. Thus, this strategy ensures that the advanced information about the environment has improved the navigation process.The authors are grateful to the Research Centre in Digitalization and Intelligent Robotics (CeDRI) for sharing its facilities and material, and also to the Foundation for Science and Technology (FCT, Portugal) for financial support as mentioned earlier.info:eu-repo/semantics/publishedVersio

Vantagens Competitivas e Fidelização “o caso Ascendum”

Num mundo em transformação, onde o mercado dos equipamentos de construção não é exceção, a fidelização de cliente é cada vez mais difícil, os produtos são cada vez mais parecidos uns com os outros, os clientes estão cada vez mais informados, esclarecidos e exigentes, e é neste contexto que os serviços de assistência técnica começam a assumir um lugar de destaque, com vista à obtenção de vantagens competitivas que permitam criar condições para fidelizar o cliente. Com este objetivo em mente propusemo-nos a realizar um “case study”, acerca da Ascendum Máquinas, e perceber que vantagens competitivas possui, e de que forma se diferencia ou poderá diferenciar no mercado, com o objetivo de fidelizar os seus clientes. Na revisão da literatura feita apresentámos diversas estratégias, possíveis de adotar, com vista à fidelização. Para cumprir os objetivos deste trabalho desenvolveu-se um estudo quantitativo, através de um questionário disponibilizado on line, que nos permitiu obter resposta de 47 clientes. Com o estudo procurámos perceber o posicionamento atual da Ascendum e recolher pistas sobre instrumentos de fidelização. Para cumprir aqueles objetivos, procurámos confirmar quatro hipóteses: Hipótese 1: A opção estratégica fundamental, na perspetiva de Porter, é a Diferenciação (através de: simpatia, imagem, capacidade técnica, tempo de resposta, qualidade dos produtos, nível tecnológico); Hipótese 2: A opção estratégica, na perspetiva de Porter, é Liderança de custo; Hipótese 3: A maioria dos clientes estão fidelizados; Hipótese 4: A venda em pacotes (peças e serviço) aumenta a fidelização. Como se percebe pelas hipóteses apresentadas, procura-se saber o posicionamento da empresa, segundo a perspetiva de Porter (1998) com as hipóteses 1 e 2, saber o grau de fidelização dos clientes através da hipótese 3 e se a fidelização melhora com ofertas de pacotes de serviço, com a hipótese 4

Aprendizado não supervisionado em sistemas de spins

Neste trabalho utilizamos algoritmos de aprendizado não supervisionado, uma classe de aprendizado de máquina, no estudo dos modelos de Ising e Potts. Iniciamos o estudo com o modelo de Ising, que possui uma vasta literatura, para familiarização dos conceitos envolvidos. Os resultados da simulação são condizentes com os encontrados na bibliografia e a aplicação das técnicas de aprendizado não supervisionado encontraram resultados similares aos obtidos por ferramentas já difundidas. As técnicas de aprendizado não supervisionado utilizados reduziram a dimensão dos dados, encontraram a região onde ocorre a transição de fase e identificaram comportamentos do sistema reduzido. As ferramentas também forneceram concepções sobre o parâmetro de ordem do modelo de Ising. Na aplicação ao modelo de Potts também foram reduzidas as dimensões dos sistemas e identificadas as regiões críticas, que variam para cada q-estados. Foram definidos parâmetros de ordem no espaço dos dados reduzidos que possuem características dos já conhecidos. Uma análise relativa ao tamanho da rede foi realizada e os parâmetros definidos possuem semelhança aos definidos na literatura. Em ambos modelos foi possível identificar correlações que não seriam facilmente identificadas com a grande quantidade de dados originais.In this work we use unsupervised learning algorithms, a class of machine learning, in the study of Ising and Potts models. We started with the study of the Ising model, which presents a vast literature, to familiarize with the concepts involved. The simulation results are consistent with those previously found in the literature and the application of unsupervised learning techniques found similar results to those obtained by common tools. The unsupervised learning techniques used reduced the dimensionality of the data, being able to locate the phase transition and identify behaviors in the reduced system. Those tools also provided insights into the order parameter of the Ising model. In the application to the Potts model, the dimensions of the systems were also reduced and the critical regions were identified, which vary for each q-states. Order parameters were defined in the space of the reduced data that have characteristics with those we already known. An analysis related to the lattice size were performed and the parameters are similar to those defined in the literature. In both models it was possible to identify correlations that would not be easily identified with the large amount of original data

Imagery : correlação entre o motor imagery e as habilidades e destrezas globais no futebol, nos gestos técnicos do passe, drible e remate em crianças de 12 e 13 anos.

Dissertação apresentada ao Instituto Politécnico de Castelo Branco para cumprimento dos requisitos necessários à obtenção do grau de Mestre em Atividade Física – Motricidade Infantil.A presente investigação tem como principal propósito verificar se existe correlação entre o imagery e as habilidades e destrezas globais do futebol, para os gestos técnicos drible, passe e remate. Pretende também contribuir para a compreensão do conceito de imagery, podendo auxiliar em estudos futuros. A amostra foi constituída por vinte e seis (26) indivíduos do sexo masculino, com idades compreendidas entre os 12 e os 13 anos (média de 12,3 ± 0,5 anos), de natureza intencional, por conveniência. Foram aplicados dois instrumentos, com o objetivo de quantificar a habilidade do sujeito na representação cinestésica e imagens visuais, o MIQ-R (Revised Movement Imagery Questionnaire), e para verificação das habilidades e destrezas globais, a bateria de testes de habilidades e destrezas globais no futebol, proposta por Mor-Christian (1979), seleccionando-se os testes de avaliação do drible, passe e remate. Os dados obtidos foram tratados no S.P.S.S. 19.0, através da estatística descritiva, mediante a frequência de ocorrências, percentuais relativos e absolutos, média e desvio padrão. Para a análise inferencial, recorremos ao teste de correlação não-paramétrico de Spearman, ao teste de correlação paramétrica de Pearson e ao teste T pares. Os resultados obtidos mostram-nos que indivíduos com maior capacidade de imagery obtiveram melhores resultados, comparativamente aos indivíduos com menor capacidade, em todos os testes específicos de habilidades e destrezas globais no futebol realizados, apresentando uma correlação fraca positiva (0,1 ≤ r < 0,5). Os resultados do MIQ-R indicaram que os indivíduos apresentaram diferenças estatisticamente significativas, apresentando valores mais elevados na modalidade visual comparativamente à modalidade cinestésica (p≤0,05). Concluímos e constatámos que existe uma correlação fraca positiva entre o “imagery” e as e as habilidades e destrezas globais no futebol, nos gestos técnicos avaliados (drible, passe e remate), para os sujeitos da amostra. Apresentaram ainda diferenças estatisticamente significativas (valores mais elevados) na modalidade visual, comparativamente à modalidade cinestésica na realização do MIQ-R

Heart rate variability activity in soccer athletes after a musculoskeletal injury

This work was funded by National Funds by FCT - Foundation for Science and Technology under the following project UIDB/04045/2020(https://doi.org/10.54499/UIDB/04045/2020)Objectives: The aim of this study is to analyse the adaptations of the autonomic nervous system after a musculoskeletal injury, obtained by measuring heart rate variability in athletes. It was hypothesized that there is an alteration in heart rate variability after a musculoskeletal injury. Study design: Cohort study. Subjects: 15 semi-professional soccer players from three football teams, aged between 21 and 33 (mean age: 29.4 ± 3.31 years), with a recent musculoskeletal injury. Methods: Heart rate variability was collected using the Polar m200 and the chest strap H10 in two moments: within 72 h after the injury and between 5 and 7 days after full return-to-play. Results: Results show differences between T1 and T2 (p ≤ 0.05) in low-frequency power (n.u.) (p = 0.001) and high-frequency power (n.u.) (p = 0.001), in low-frequency/high-frequency ratio (p = 0.001) and in high-frequency power (ms2) (p = 0.017) measures. No statistical differences were found in low-frequency power (ms2) (p = 0.233). The low frequency power (n.u.) was significantly lower after injury compared with LF power (n.u.) values after full return-to-play. In high-frequency power there was a significant difference between both moments with high values after injury. Conclusions: The use of heart rate variability therefore seems to be promising to detect an imbalance in the autonomic nervous system and help clinical departments to identify a possible non-traumatic musculoskeletal injury. Further research should be performed considering a wide range of musculoskeletal injuries and to establish baseline values of the athletes.info:eu-repo/semantics/publishedVersio

Heart rate variability behavior in athletes after a sports concussion: A systematic review

Objective This systematic review aims to investigate the adaptations of the autonomic nervous system (ANS) after a concussion by measuring HRV in athletes over the age of 16 after injury. Methods This systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). Web of Science, Pubmed, SCOPUS, and Sport Discus were searched using predefined search terms to identify relevant original cross-sectional, longitudinal, and cohort epidemiological studies published before December 2021. Results After screening 1737 potential articles, four studies met the inclusion criteria. Studies included participants with concussion (n = 63) and healthy control athletes (n = 140) who practised different sports. Two studies describe a decrease in HRV following a sports concussion, and one proposed that the resolution of symptoms does not necessarily reflect ANS recovery. Lastly, one study concluded that submaximal exercise induces alteration in ANS, not seen in rest after an injury. Conclusions In the frequency domain, a decrease in high frequency power and an increase of low frequency/high frequency ratio is expected, as the activity of the sympathetic nervous system increases, and the parasympathetic nervous system decreases after injury. In the frequency domain, heart rate variability (HRV) may help monitor the activity of ANS evaluating signals of somatic tissue distress and early identification of other types of musculoskeletal injuries. Further research should investigate the relationship between HRV and other musculoskeletal injuries.info:eu-repo/semantics/publishedVersio

Effects of combined training on metabolic profile, lung function, stress and quality of life in sedentary adults: a study protocol for a randomized controlled trial

Background Both physical inactivity and sedentary behavior are considered modifiable risk factors for chronic diseases and all-cause mortality. Adult office-workers spend most of their working day in sedentary behaviors, so they are particularly at high risk of developed chronic diseases (e.g., cardiovascular diseases, metabolic disorders like diabetes mellitus, . . .). It seems important to promote behavioral changes that could prevent or delay metabolic disease development. Evidence supports the use of exercise programs, however, to date there are several knowledge gaps and inconsistencies in the literature regarding the effects of Combined Training (i.e., aerobic plus resistance training) in sedentary healthy adults. This paper outlines an RCT designed to evaluate the effects of a 16-week combined training program on biochemical and immune markers of metabolic disease, lung function, salivary stress hormones and subjective quality of life (primary outcomes), as well as on body composition and physical fitness (secondary outcomes) in sedentary middle-aged office-workers. Furthermore, we aimed to assess the associations between the changes promoted by the exercise program and the different variables studied. Methods and design This is a single-blinded two-arm RCT with parallel groups. A minimum of healthy 40 officeworkers aged 40–64 years will be recruited to engage in a 16-week intervention study. After baseline assessments, participants will be randomized to one of the two groups: (1) combined training group or (2) control group. Baseline assessments will be repeated after 8 weeks of intervention (mid-testing) and upon completion of the intervention (post-testing). Discussion This RCT involves a multi-disciplinary approach and seems to be a relevant contribution to understanding the potential role of combined training in improving the metabolic profile, lung function, stress, and quality of life in adults. The results can provide important insights for clinical recommendations and for the optimization of strategies to prevent metabolic disorders in adults with sedentary jobs.info:eu-repo/semantics/publishedVersio