936 resultados para attitude
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Como crítica à perspectiva da Educação Física Escolar (EFE) voltada à aptidão física e ao desenvolvimento técnico-esportivo, tão comum até a década de 1970, surgem, a partir da década de 1980, novas propostas de ensino que a aproximariam dos reais objetivos da escola é o que se chama de movimento renovador da EFE. Ao longo dos anos, essas propostas foram incorporadas aos cursos de graduação, de pós-graduação e aos documentos oficiais de ensino. Era de se esperar que as aulas de EFE nas escolas brasileiras, hoje, representassem, hegemonicamente, as propostas do movimento renovador, mas paradoxalmente temos visto intervenções difusas e até aleatórias, muitas vezes representadas pelo rola a bola. Diante da necessidade de investir em práticas renovadoras e a fim de abolir o caráter de estudos que apenas pomovem denúncias de práticas caducas, este estudo buscou professores que, alinhados aos conhecimentos renovadores, procuram desenvolver aulas de EFE que se aproximam e representam tais conhecimentos didático-metodológicos. Assim, buscou-se investigar a influência do movimento renovador na intervenção pedagógica de cinco professores de Educação Física da rede municipal de ensino do Rio de Janeiro. O estudo divide-se em três artigos complementares. O primeiro traz a problematização e a revisão bibliográfica. O segundo busca identificar o que os professores pensam acerca do movimento renovador, bem como analisar características acadêmicas e profissionais-interventivas. Os resultados do artigo 2 apontam que os professores parecem conhecer, se alinham e afirmam ministrar aulas em acordo com as propostas renovadoras, mas possuem ambientes e condições de trabalho distintas. O terceiro artigo traz a análise de 20 aulas de EFE dos cinco professores, a partir de uma ficha de observação sistemática composta por indicadores didático-metodológicos sugeridos por Resende e Nascimento (2004), além da discussão de uma entrevista sobre questões didáticas e metodológicas e críticas às intervenções. Percebeu-se que, apesar de intervenções com características distintas, a maioria das ações intervetivas se aproximou dos indicadores nas categorias planejamento, objetivo, conteúdo, método, avaliação e relação professor-aluno. Todos os professores fizeram críticas às aulas, acreditando que estas deveriam ser melhores e diferentes do que frequentemente são, o que representa limitações do campo interventivo e o compromisso dos professores com a qualidade da intervenção. Acredita-se que os dados deste estudo representam mais um pequeno passo às discussões e construções de práticas renovadoras no campo da EFE, ao buscar e apontar possibilidades, limitações e exemplos de ações didáticas concretas do cotidiano.
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Trata-se de uma tese de doutoramento, cujo tema de estudo é DASPU. Fundada em 2005, reconhecida no Brasil e internacionalmente, é vinculada à ONG DAVIDA que se ocupa de questões relacionadas com Prostituição, Direitos Civis, Direitos Humanos e Prevenção de DST/AIDS. A proposta é a de abordar os quase cinco anos de existência da marca, considerando-os como quatro movimentos. Os pressupostos teóricos e metodológicos partem de Bruno Latour, dentre outros autores. A ênfase está na interdisciplinaridade entre Design, Moda e Psicologia Social. A prática da observação participante, adotada ao longo da trajetória, propicia intervenções com objetivos relacionados com a identificação das múltiplas possibilidades de rearranjos sociais e coletivos.
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This paper addresses the problem of recovering the 3D shape of a surface of revolution from a single uncalibrated perspective view. The algorithm introduced here makes use of the invariant properties of a surface of revolution and its silhouette to locate the image of the revolution axis, and to calibrate the focal length of the camera. The image is then normalized and rectified such that the resulting silhouette exhibits bilateral symmetry. Such a rectification leads to a simpler differential analysis of the silhouette, and yields a simple equation for depth recovery. It is shown that under a general camera configuration, there will be a 2-parameter family of solutions for the reconstruction. The first parameter corresponds to an unknown scale, whereas the second one corresponds to an unknown attitude of the object. By identifying the image of a latitude circle, the ambiguity due to the unknown attitude can be resolved. Experimental results on real images are presented, which demonstrate the quality of the reconstruction. © 2004 Elsevier B.V. All rights reserved.
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In this paper we consider the problem of constructing a distributed feedback law to achieve synchronization for a group of k agents whose states evolve on SO(n) and which exchange only partial state information along communication links. The partial state information is given by the action of the state on reference vectors in ℝn. We propose a gradient based control law which achieves exponential local convergence to a synchronization configuration under a rank condition on a generalized Laplacian matrix. Furthermore, we discuss the case of time-varying reference vectors and provide a convergence result for this case. The latter helps reach synchronization, requiring less communication links and weaker conditions on the instantaneous reference vectors. Our methods are illustrated on an attitude synchronization problem where agents exchange only their relative positions observed in the respective body frames. ©2009 IEEE.
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This paper reports a survey on people with age-related and physical impairments in India. The survey evaluates functional parameters related to human computer interaction and reports subjective attitude and exposure of users towards technology. We found a significant cognitive decline in elderly users while their functional parameters are sufficient to use existing electronic devices. However young disabled users are found to be experienced with computer but could not have access to appropriate assistive devices, which would benefit them. Most users used desktop computers and mobile phone but none used tablet, smartphone or kiosks though they are keen to learn new technologies. Overall we hope that our results will be useful for HCI practitioners in developing countries. © 2013 Springer-Verlag Berlin Heidelberg.
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该文在对新疆水土流失的现状、特点的分析的基础上 ,对现实存在着的水蚀强度、戈壁的风蚀强度、盐碱地的归属和侵蚀交错类型的分隔等问题进行了讨论 ,提出了自己的观点和看法 ,为水土流失调查提供借鉴
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海洋监测是人类认识海洋、研究海洋的有利工具,海洋自动观测仪器又是海洋监测技术最基本的硬件单元。文章介绍了一种具有自主知识产权的海洋仪器产品——节能型自治式多功能海洋环境监测系统,并对其做了静力分析和姿态计算。 该测量系统将定点锚泊潜标和浮标技术相结合,并创新性的融进了节能技术,使其具有长期、安全和多参数测量的工作特点。 为确保系统能在水下长期可靠地工作,文章对系统在水下的受力状况和姿态进行了计算。由于系统潜标式主浮体在水下几十米,海面波浪对其影响较小,仅对系统在海流的作用下进行水下静力分析。计算中首先根据总体技术要求进行合理的简化和假设,建立水下系统的数学模型,编制系统在水下的受力和姿态计算软件,完成系统的结构配置、受力分析和水下姿态的计算。 值得注意的是,该系统的潜标式主浮体受力分析方法与传统简单构形(一个浮体,一根索和一个锚)的分析方法不同,因为该潜标式主浮体不但受到下端缆绳的拉力,而且还受到连结上端搭载平台缆绳的拉力,同时还要考虑进变化海流对缆绳的作用。 最后,用MATLAB编制了相应程序。该程序操作方便,每次任务确定之后,只需向计算机输入阻尼系数、浮力重力值、浮球直径及潜标长度等参数,程序将自动计算出水下系统在 流速范围内各部件的横倾角、缆绳拉力及拉力与水平线(垂直线)夹角等有关参数,供系统配置做参考。
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In many plant species, leaf morphology varies with altitude, an effect that has been attributed to temperature. It remains uncertain whether such a trend applies equally to juvenile and mature trees across altitudinal gradients in semi-arid mountain regions. We examined altitude-related differences in a variety of needle characteristics of juvenile (2-m tall) and mature (5-m tall) alpine spruce (Picea crassifolia Kom.) trees growing at altitudes between 2501 and 3450 m in the Qilian Mountains of northwest China. We found that stable carbon isotope composition (delta C-13), area- and mass-based leaf nitrogen concentration (N-a, N-m), number of stomata per gram of nitrogen (St/N), number of stomata per unit leaf mass (St/LM), projected leaf area per 100 needles (LA) and leaf mass per unit area (LMA) varied nonlinearly with altitude for both juvenile and mature trees, with a relationship reversal point at about 3 100 m. Stomatal density (SD) of juvenile trees remained unchanged with altitude, whereas SD and stomatal number per unit length (SNL) of mature spruce initially increased with altitude, but subsequently decreased. Although several measured indices were generally found to be higher in mature trees than in juvenile trees, N-m, leaf carbon concentration (C.), leaf water concentration. (LWC), St/N, LA and St/LM showed inconsistent differences between trees of different ages along the altitudinal gradient. In both juvenile and mature trees, VC correlated significantly with LMA, N-m, N-a, SNL, St/LM and St/N. Stomatal density, LWC and LA were only significantly correlated with delta C-13 in mature trees. These findings suggest that there are distinct ecophysiological differences between the needles of juvenile and mature trees that determine their response to changes in altitude in semi-arid mountainous regions. Variations in the fitness of forests of different ages may have important implications for modeling forest responses to changes in environmental conditions, such as predicted future temperature increases in high attitude areas associated with climate change.
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Adaptation to hypoxia is regulated by hypoxia-inducible factor 1 (HIF-1), a heterodimeric transcription factor consisting of an oxygen-regulated a-subunit and a constitutively expressed beta-subunit. How animals living on Qinghai-Tibetan plateau adapt to the extreme hypoxia environment is known indistinctly. In this study, the Qinghai yak which has been living at 3000-5000 m attitude for at least two millions of years was selected as the model of high hypoxia-tolerant adaptation species. The HIF-1 alpha ORFs (open reading frames) encoding for two isoforms of HIF-1 alpha have been cloned from the brain of the domestic yak. Its expression of HIF-1 alpha was analyzed at both mRNA and protein levels in various tissues. Both its HIF-1 alpha mRNA and protein are tissue specific expression. Its HIF-1 alpha protein's high expression in the brain, lung, and kidney showed us that HIF-1 alpha protein may play an important role in the adaptation to hypoxia environment. (c) 2006 Elsevier Inc. All rights reserved.
Resumo:
Leptin, an adipocyte-derived hormone, plays all important role in body energy homeostasis. Plateau pika (Ochotona curzoniae), an endemic and keystone species living only at 3000-5000 in above sea level oil Qinghai-Tibet Plateau, is a typically high hypoxia and low temperature tolerant mammal with high resting metabolic rate (RMR), non-shivering thermogenesis (NST), and high ratio of oxygen utilization to cope with harsh plateau environment. To explore the molecular mechanism of ecological acclimation in plateau pika, we first cloned pika leptin cDNA and compared its mRNA expression in different altitudes (3200 and 3900 in) using real-time RTPCR (Taqman probe) technology. The full-length pika leptin cDNA was 3015 with 504 bp open-reading frame encoding the precursor peptide of 167 amino acids including 21 residues of signal peptide. Pika leptin was 70-72% homologous to that of other species and was of similarly structural characteristics with other species. The pika-specific genetic diversity in leptin sequence occurred at twenty sites. With the increase in attitude, there were larger fat store and high level of ob gene expression in plateau pika. Our results indicated that leptin is sensitive to cold and hypoxia plateau environment and may play one of important roles in pika's ecological adaptation to harsh plateau environment. (c) 2006 Elsevier Inc. All rights reserved.
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空间机器人和大型柔性空间结构在航天器调姿、变轨、外部扰动的情况下将引起振动问题,其低频大幅值振动将持续很长时间,这将影响航天器系统的稳定性和控制精度。为了快速抑制低频大幅值振动及残余振动,提出采用复合可控反作用力幅值的喷气式驱动和压电陶瓷驱动方案进行振动控制。进行基于复合控制的柔性臂系统动力学建模并给出控制算法。设计并建立柔性机械臂试验平台,构建气动驱动控制回路及压电驱动控制回路。进行基于压电陶瓷驱动器、喷气式驱动器及复合喷气和压电驱动器的柔性臂大幅值低频模态振动控制的几种方法试验比较研究。试验结果表明,采用的控制方案和方法既可以快速地抑制柔性机械臂统的低频大幅值振动,又明显地同时抑制高频和低频小幅值残余振动。
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以一种3自由度并联驱动机器人为研究对象,研究这种机器人的变刚度特性。从操作臂的静力学出发,对并联柔索驱动机器人的刚度进行了分析得到刚度公式。从得到的公式可以看出,操作臂的刚度不仅与各分支的刚度有关,与操作臂位姿有关,还与张紧柔索的张紧力有关。在机器人各分支上串联刚度较低的弹簧后做刚度实验,试验结果验证了对刚度理论分析所得的结论。
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以无人机天际线识别为背景,提出了一种准确、实时的天际线识别算法,并由此估计姿态角。在结合实际情况的基础上,对天际线建立能量泛函模型,利用变分原理推出相应偏微分方程。在实际应用中出于对实时性的考虑,引入直线约束对该模型进行简化,然后利用由粗到精的思想识别天际线。首先,对图像预处理并垂直剖分,然后利用简化的水平直线模型对天际线进行粗识别,通过拟合获得天际线粗识别结果,最后在基于梯度和区域混合开曲线模型约束下精确识别天际线,并由此估计无人机滚动和俯仰姿态角。实验结果表明,该算法对天际线识别具有较好的鲁棒性、准确性和实时性。
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本文提出了一种结构化环境下,基于立体视觉的机器人楼梯识别算法,并将算法该应到自主移动机器人上。该算法首先利用二维图像分析的方法搜索楼梯的疑似区域;进而利用立体视觉对各个疑似区域进行精确三维重建,结合三维信息重构楼梯平面,排除虚假疑似楼梯区域;最后判定机器人和楼梯的相对位姿关系,引导机器人爬楼梯。最终我们将该算法应用到了自主移动机器人上,通过在各种光照条件下的实验,进一步验证了该算法的准确性和快速性。
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提出了用于测量平面运动位姿的三自由度串联和并联测量方法,介绍了串联和并联测量方法的测量原理.通过建立串联测量方法的误差模型,得出了几何误差源与原始测量参数的映射关系和对末端位姿误差的影响情况,得到了这种方法的精度分析结果.仿真结果和试验数据证明了分析的正确性.同时,从几何误差源的产生和测量运动特性等方面对串联和并联测量方法进行了比较.