22 resultados para positive velocity and position feedback


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Dissertação para obtenção do Grau de Mestre em Engenharia Electrotécnica e de Computadores

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RESUMO: O Biofeedback cinemático na realização de exercícios escápulo-torácicos Patrícia Ribeiro; Ricardo Matias Desenho do estudo: Estudo quantitativo, experimental, prospetivo de fator único. Objetivos: Determinar a efetividade do biofeedback cinemático tridimensional (3D) em tempo real, como informação de retorno extrínseca, no reconhecimento da zona neutra da omoplata, em indivíduos saudáveis; medir o desempenho temporal, através do tempo que os sujeitos demoram a atingir a posição pretendida, e o desempenho no percurso, através da diferença entre o percurso efetuado e aquele que seria o percurso mais curto, sem Informação de Retorno Extrínseca (IRE), com Informação de Retorno Extrínseca clinica verbal e palpatória (IRE-VP) e com informação de retorno extrínseca visual cinemática (IRE-VC). Enquadramento: Reconhecer aquela que deve ser a posição adequada da omoplata e tomar consciência da importância dessa posição para a estabilidade e correto funcionamento da articulação gleno-umeral é uma tarefa difícil, pois a grande maioria do indivíduos não têm os conhecimentos necessários. É reconhecido o contributo que a IRE tem na reaprendizagem motora, em especial na primeira fase da aprendizagem motora – a consciencialização. Vários estudos se têm debruçado em avaliar a influencia da IRE na reabilitação de indivíduos com disfunção do ombro, tendo-se limitado ao formato electromiográfico. No sentido de encontrar novas estratégias para facilitar o processo de reaprendizagem motora nestes indivíduos, foi escolhido biofeedback cinemático tridimensional. Métodos: Participaram no estudo 60 sujeitos, sem queixas de dor no ombro, com idades compreendidas entre os 18 e os 54 anos, com um valor médio de 21,66 anos (±5.89), divididos aleatoriamente em três grupos com uma tarefa comum: o reconhecimento da zona neutra da omoplata. Um grupo não recebeu qualquer tipo de IRE - Grupo Controlo (GC), outro grupo recebeu IRE-VP e outro recebeu IRE-VC. Para efeitos de análise da performance foram consideradas duas variáveis: tempo e qualidade da execução. A abordagem estatística destas variáveis consistiu numa análise de variância simples e num teste de comparações múltiplas. Resultados: Observámos que o grupo controlo e o grupo IRE-VC efetuaram a tarefa pedida em menos tempo que o grupo IRE-VP (p<0.01) e que o grupo IRE-VC obteve melhores resultados no que respeita à qualidade da execução da tarefa do que o GC e o grupo IRE-VP (p<0.01). Conclusão: Pelos resultados obtidos, na tarefa de reconhecimento da zona neutra da omoplata, podemos concluir que o biofeedback cinemático é mais efetivo na facilitação da obtenção de melhor qualidade de execução da tarefa do que o feedback clinico ou a inexistência de feedback e igualmente efetivo à inexistência de IRE no que respeita ao tempo demorado a reconhecer essa posição. -------------- ABSTRACT:Study Design: Single factor experimental design. Objectives: To determine the effectiveness of real time cinematic biofeedback as extrinsic information in the recognition of the neutral zone of the scapula in healthy subjects; to measure the temporal performance and quality of the execution without extrinsic feedback, with clinical feedback and with cinematic feedback. Background: To recognize the proper scapula position and to be aware of the importance of this position to the stability and correct function of the gleno-umeral joint is a difficult task, because most people don’t have the necessary knowledge. It is known that extrinsic feedback is effective in motor learning, specially in the early stages. There are several studies that evaluated the influence of extrinsic feedback in rehabilitation of shoulder dysfunctions, but only in the electromyography format. Material and Methods: Sixty healthy subjects were randomly divided into 3 groups that received no feedback (group 1 – control group), verbal and palpatory feedback (group 2) and real time cinematic feedback (group 3). The performance variables considered – time and quality of execution - were statistically analyzed with ANOVA one-way and multiple comparisons test. Results: Control group and group 3 executed the task in less time that group 2 (p<0.01) and group 3 executed the task with better quality than control group and group 2 (p<0.01). Conclusions: From the results of this study we conclude that in the studied task, the cinematic feedback is more effective to facilitate a better quality of execution than no feedback or clinical feedback and, regarding to time taken to attain the requested position, equally effective to no feedback.

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A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics

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This work project aims at analysing choices related to Comprehensive income (CI) of Portuguese listed firms and understanding the reasons behind them. Additionally, it studies the relevance of CI versus Net Income (NI). It was found that firm’s size and volume of Other comprehensive income (OCI) are positively related with the choice for separate statements while smaller firms with positive NI and negative OCI tend to disclose less information about taxes. The value relevance of CI proved to be superior to that of NI but OCI seems to have no incremental value relevance.

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The thrust towards energy conservation and reduced environmental footprint has fueled intensive research for alternative low cost sources of renewable energy. Organic photovoltaic cells (OPVs), with their low fabrication costs, easy processing and flexibility, represent a possible viable alternative. Perylene diimides (PDIs) are promising electron-acceptor candidates for bulk heterojunction (BHJ) OPVs, as they combine higher absorption and stability with tunable material properties, such as solubility and position of the lowest unoccupied molecular orbital (LUMO) level. A prerequisite for trap free electron transport is for the LUMO to be located at a level deeper than 3.7 eV since electron trapping in organic semiconductors is universal and dominated by a trap level located at 3.6 eV. Although the mostly used fullerene acceptors in polymer:fullerene solar cells feature trap-free electron transport, low optical absorption of fullerene derivatives limits maximum attainable efficiency. In this thesis, we try to get a better understanding of the electronic properties of PDIs, with a focus on charge carrier transport characteristics and the effect of different processing conditions such as annealing temperature and top contact (cathode) material. We report on a commercially available PDI and three PDI derivatives as acceptor materials, and its blends with MEH-PPV (Poly[2-methoxy 5-(2-ethylhexyloxy)-1,4-phenylenevinylene]) and P3HT (Poly(3-hexylthiophene-2,5-diyl)) donor materials in single carrier devices (electron-only and hole-only) and in solar cells. Space-charge limited current measurements and modelling of temperature dependent J-V characteristics confirmed that the electron transport is essentially trap-free in such materials. Different blend ratios of P3HT:PDI-1 (1:1) and (1:3) show increase in the device performance with increasing PDI-1 ratio. Furthermore, thermal annealing of the devices have a significant effect in the solar cells that decreases open-circuit voltage (Voc) and fill factor FF, but increases short-circuit current (Jsc) and overall device performance. Morphological studies show that over-aggregation in traditional donor:PDI blend systems is still a big problem, which hinders charge carrier transport and performance in solar cells.

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The work reported in this thesis addresses the research question of when and how positive psychological states impact positive behavior and positive organizational development. We present two theoretical essays and three empirical studies to find possible answers to this question and we use a multitude of methodologies with different epistemological assumptions, including quantitative correlation analysis, social network analysis and qualitative grounded theory analysis. In the whole, our work shows that positive psychological states are fundamental to promote individual and organizational higher-levels of performance and well-being. It also points that the capability to induce positive psychological states in others (an “alter-positive” approach) is a powerful way to develop outstanding individuals and organizations. In a broader sense, it stresses the need to promote good vibrations as a fundamental route to create a better world.