867 resultados para Joint Angular Velocity


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Comunicação apresentada na 18th Conference International of Health Promotion Hospitals & Health Services "Tackling causes and consequences of inequalities in health: contributions of health services and the HPH network", em Manchester de 14-16 de april de 2010

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1st European IAHR Congress,6-4 May, Edinburg, Scotland

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1st European IAHR Congress, 6-4 May, Edinburgh, Scotland

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We agree with Ling-Yun et al. [5] and Zhang and Duan comments [2] about the typing error in equation (9) of the manuscript [8]. The correct formula was initially proposed in [6, 7]. The formula adopted in our algorithms discussed in our papers [1, 3, 4, 8] is, in fact, the following: ...

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Dissertação para obtenção do grau de Doutor em Engenharia Electrotécnica - Energia pela Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa

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The power systems operation in the smart grid context increases significantly the complexity of their management. New approaches for ancillary services procurement are essential to ensure the operation of electric power systems with appropriate levels of stability, safety, quality, equity and competitiveness. These approaches should include market mechanisms which allow the participation of small and medium distributed energy resources players in a competitive market environment. In this paper, an energy and ancillary services joint market model used by an aggregator is proposed, considering bids of several types of distributed energy resources. In order to improve economic efficiency in the market, ancillary services cascading market mechanism is also considered in the model. The proposed model is included in MASCEM – a multi-agent system electricity market simulator. A case study considering a distribution network with high penetration of distributed energy resources is presented.

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The provision of reserves in power systems is of great importance in what concerns keeping an adequate and acceptable level of security and reliability. This need for reserves and the way they are defined and dispatched gain increasing importance in the present and future context of smart grids and electricity markets due to their inherent competitive environment. This paper concerns a methodology proposed by the authors, which aims to jointly and optimally dispatch both generation and demand response resources to provide the amounts of reserve required for the system operation. Virtual Power Players are especially important for the aggregation of small size demand response and generation resources. The proposed methodology has been implemented in MASCEM, a multi agent system also developed at the authors’ research center for the simulation of electricity markets.

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Increased demands on the capacity of the railway network gave rise to new issues related to the dynamic response of railway tracks subjected to moving vehicles. Thus, it becomes important to evaluate the applicability of traditionally used simplified models which have a closed form solution. Regarding simplified models, transversal vibrations of a beam on a visco-elastic foundation subjected to a moving load are considered. Governing equations are obtained by Hamilton’s principle. Shear distortion, rotary inertia and effect of axial force are accounted for. The load is introduced as a time varying force moving at a constant velocity. Transversal vibrations induced by the load are solved by the normal-mode analysis. Reflected waves at the extremities of the full beam are avoided by introduction of semi-infinite elements. Firstly, the critical velocity obtained from this model is compared with results of an undamped Euler- Bernoulli formulation with zero axial force. Secondly, a finite element model in ABAQUS is examined. The new contribution lies in the introduction of semi- infinite elements and in the first step to a systematic comparison, which have not been published so fa

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We present a novel approach of Stereo Visual Odometry for vehicles equipped with calibrated stereo cameras. We combine a dense probabilistic 5D egomotion estimation method with a sparse keypoint based stereo approach to provide high quality estimates of vehicle’s angular and linear velocities. To validate our approach, we perform two sets of experiments with a well known benchmarking dataset. First, we assess the quality of the raw velocity estimates in comparison to classical pose estimation algorithms. Second, we added to our method’s instantaneous velocity estimates a Kalman Filter and compare its performance with a well known open source stereo Visual Odometry library. The presented results compare favorably with state-of-the-art approaches, mainly in the estimation of the angular velocities, where significant improvements are achieved.

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Health promotion in hospital environments can be improved using the most recent information and communication technologies. The Internet connectivity to small sensor nodes carried by patients allows remote access to their bio-signals. To promote these features the healthcare wireless sensor networks (HWSN) are used. In these networks mobility support is a key issue in order to keep patients under realtime monitoring even when they move around. To keep sensors connected to the network, they should change their access points of attachment when patients move to a new coverage area along an infirmary. This process, called handover, is responsible for continuous network connectivity to the sensors. This paper presents a detailed performance evaluation study considering three handover mechanisms for healthcare scenarios (Hand4MAC, RSSI-based, and Backbone-based). The study was performed by simulation using several scenarios with different number of sensors and different moving velocities of sensor nodes. The results show that Hand4MAC is the best solution to guarantee almost continuous connectivity to sensor nodes with less energy consumption.

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1.Pre-assessment data of the patient A 2-year-old boy, weighing 15 kg was admitted with a history of limited mouth opening(inter-incisor distance of 6 mm), hypoplastic and retrognathic mandible (bird face deformity) and facial asymmetry from left temporomandibular joint ankylosis (TMJA). He was born at term, after an uneventful pregnancy, and there was no report of trauma during caesarean section. No other possible aetiologies were identified. He was scheduled for mandibular osteotomy. Preoperative ENT examination revealed adenotonsillar hypertrophy. 2. Anaesthetic Plan A fiberoptic nasal intubation was performed under deep inhalation anaesthesia with sevoflurane, with the patient breathing spontaneously. Midazolam (0.05 mg.kg-1) and alfentanil (0.03 mg.kg-1) were given and anaesthesia was maintained with O2/air and sevoflurane. No neuromuscular blocking agent was administered since the surgical team needed facial nerve monitoring. 3. Description of incident During surgery an accidental extubation occurred and an attempt was made to reintubate the trachea by direct laryngoscopy. Although the osteotomy was nearly completed, the vocal cords could not be visualized (Cormack-Lehane grade IV laryngoscopic view). 4. Solving the problem Re-intubation was finally accomplished with the flexible fiberscope and the procedure was concluded without any more incidents. Extubation was performed 24 hours postoperatively with the patient fully awake. After surgery mouth opening improved to inter-incisor gap of 15 mm. 5. Lessons learned and take home message Two airways issues present in this case can lead to difficultventilation and intubation: TMJA and adenotonsillar hypertrophy. These difficulties were anticipated and managed accordingly. The accidental extubation brought to our attention the fact that, even after surgical correction, this airway remains challenging. Even with intensive jaw stretchingexercises there is a high incidence of re-ankylosis, especially in younger patients. One should bear that in mind when anaesthetizing patients with TMJA.

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O trabalho desenvolvido no decurso da elaboração da dissertação aqui apresentada decorreu no departamento de Metrologia do Instituto Português da Qualidade no âmbito de estágio. O tema que foi abordado está inserido na área de Metrologia Angular, onde a grandeza que se mede é o ângulo plano. Por esse facto os dois equipamentos de medição principais que foram utilizados foram o autocolimador e a mesa rotativa. O objectivo principal do trabalho visou a utilização de novas técnicas de avaliação de dados, que consistiu na separação dos erros do autocolimador e da mesa rotativa, quando a calibrar o autocolimador e trabalhá-los separadamente com o propósito de verificar se as incertezas são mais baixas relativamente aos métodos clássicos de calibração e assim garantir uma maior exactidão nos resultados. Este trabalho implicou a implementação de uma nova técnica de medição, assim como a implementação de um novo processo de obtenção dos dados. Estas técnicas baseiam-se em aplicar certos desvios aos dois sistemas que vão permitir a construção dos erros separadamente, tanto do autocolimador como da mesa rotativa, e que vai permitir, deste modo, que não seja necessário recorrer a padrões externos. A obtenção desses erros foi construída utilizando as Transformadas de Fourier Discretas, pois através destas é possível recuperar/gerar valores que entretanto se perderam, ou não foram possíveis de adquirir. Com o trabalho realizado, o laboratório implementou um novo método de calibração do sistema composto pelos instrumentos de medição, autocolimador e mesa rotativa, garantindo que os erros estão em conformidade

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The vulnerability of the masonry envelop under blast loading is considered critical due to the risk of loss of lives. The behaviour of masonry infill walls subjected to dynamic out-of-plane loading was experimentally investigated in this work. Using confined underwater blast wave generators (WBWG), applying the extremely high rate conversion of the explosive detonation energy into the kinetic energy of a thick water confinement, allowed a surface area distribution avoiding also the generation of high velocity fragments and reducing atmospheric sound wave. In the present study, water plastic containers, having in its centre a detonator inside a cylindrical explosive charge, were used in unreinforced masonry infills panels with 1.7m by 3.5m. Besides the usage of pressure and displacement transducers, pictures with high-speed video cameras were recorded to enable processing of the deflections and identification of failure modes. Additional numerical studies were performed in both unreinforced and reinforced walls. Bed joint reinforcement and grid reinforcement were used to strengthen the infill walls, and the results are presented and compared, allowing to obtain pressure-impulse diagrams for design of masonry infill walls.

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The force distribution inside a dovetail joint is complex. Wood is simultaneously loaded in different directions in the several connected surfaces. The analytical solutions available for the analysis of the behavior of those carpentry joints rely on the mechanical properties of wood. In particular, the stiffness properties of wood under compression are crucial for the forces equilibrium. Simulations showed that the stiffness values considered in each of the springs normally assumed in the analytical models, have great influence in the bearing capacity and stiffness of the dovetail joints, with important consequence on the stress distribution over the overall structure. In a wide experimental campaign, the properties under compression of the most common wood species of existing timber structures have been determined. Then, a solved example of a dovetail joint is presented assuming different wood species and the corresponding strength and stiffness properties values obtained in the tests.

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Dovetail joints are one of the most cornrnonly used joints during Gothic and Baroque periods. Despite being coristructed in the sarne way during the ages, there is no analyticai solution available to help its analysis and design so required in reconstruction works of existing timber structures. An analytical solution based on the principie of virtual works under different types of loading is presented in this paper as weli as differences in bearing capacity of the joint for chosen types of loading, when different wood species are used. The accuracy of the presented solution is confirrned by data obtained from experimental tests of scaied modeis of a dovetail joint.