Quasi-periodic Gaits in Multi-legged Robots

5th International Conference on Climbing and Walking Robots and the Support Technologies for Mobile Machines

Energy analysis of Multi-legged Locomotion Systems

4th International Conference on Climbing and Walking Robots - From Biology to Industrial Applications

Temporomandibular Joint Ankylosis in an Infant: A Rare Cause of Difficult Airway

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.

Efectividade de um programa de exercício aquático na osteoartrose do joelho

RESUMO: A osteoartrose do joelho é uma condição clínica cuja prevalência tem aumentado nos últimos anos na população idosa. Trata-se de uma condição que pode ser bastante incapacitante para o idoso, gerando um forte impacto social e económico. O exercício aquático tem sido identificado como um factor de promoção da melhoria do quadro clínico nesta população, mas a sua efectividade não está, ainda, determinada. Objectivo: investigar a efectividade, a curto e médio prazo, de um programa de exercício aquático, realizado em grupo, com a duração de 8 semanas, na amplitude articular, dor e rigidez do joelho, e na função física e qualidade de vida, em idosos com osteoartrose do joelho. Metodologia: Recorreu-se a um estudo quase-experimental, double-blind, controlado, sem aleatorização, cuja amostra, constituída por 43 sujeitos, foi selecionada por conveniência. Os sujeitos do grupo experimental (n=22) foram submetidos ao programa de exercício aquático e os do grupo de controlo (n=21) foram submetidos ao programa de exercício no solo. Ambos os programas foram definidos de acordo com as recomendações internacionais para a prática de exercício físico em idosos com osteoartrose (Arthritis Foundation, 2009a, 2009b). Todo o grupo foi avaliado no início do programa, no final do mesmo (8 semanas) e após 6 semanas de follow-up, nos seguintes indicadores: amplitude articular do joelho (através do goniómetro), dor, rigidez, função e qualidade de vida (através do KOOS). Resultados: A amostra deste estudo foi constituída por sujeitos maioritariamente do género feminino (76,7%), com uma média de 72,7 anos (DP=5,49). O programa de exercício aquático implementado demonstrou um aumento da amplitude articular passiva de flexão (p<0,0001) e extensão (p=0,016) do joelho, uma diminuição da dor e da rigidez articular (p<0,0001), um aumento da função nas AVD’s (p<0,0001) e no desporto/lazer (p=0,031), e ainda, um aumento da qualidade de vida (p<0,0001). Contudo, apenas os níveis de amplitude articular passiva de extensão do joelho (p=0,083) e de função no desporto/lazer (p=0,244) se mantiveram ao longo das seis semanas de follow-up. Conclusões: Apesar de algumas limitações, considera-se que este estudo é de grande importância para a comunidade científica e para os fisioterapeutas preocupados com a crescente prevalência da osteoartrose e dos custos associados. O exercício aquático parece ser uma estratégia importante na melhoria do estado de saúde dos idosos com osteoartrose do joelho.----------------- ABSTRACT: The osteoarthritis of the knee is a clinical condition that has been increasing among the elderly population over the past few years. It’s a condition that can be fairly disabling to the elderly individual, and which generates a strong social and economic impact. Aquatic exercise has been named as a promotional factor in the improvement of the clinical picture in this population, but its effectiveness is yet to be determined. Objective: To investigate the effectiveness, in a short and medium term, of an aquatic exercise program undertaken by a group over eight weeks, in the joint amplitude, pain and stiffness of the knee, and in the physical function and quality of life in elderly people who suffer from knee osteoarthritis. Methodology: was used a double-blind, quasi-experimental study with no randomization and its 43 subjects were selected as a matter of convenience. The subjects of the experimental group (n=22) were subjected to an aquatic exercise program and those of the control group (n=21) were subjected to a land-based exercise program. Both programs have followed international recommendations on the practice of physical exercise in elderly people who suffer from osteoarthritis (Arthritis Foundation, 2009a, 2009b). The entire group was evaluated in the beginning and at the end of the program (8 weeks later), and after a 6 week follow-up, in these parameters: knee range of motion (through a goniometer), pain, stiffness, function and quality of life (through KOOS). Results: This sample was predominantly female (76,7%) with a mean age of 72,7 years (SD=5,49). Aquatic exercise resulted in increase of passive joint flexion (p<0,0001) and knee extension (p=0,016), in the decline of pain and stiffness (p<0,0001), in the increase of function in the ADLs (p<0,0001). However, only the knee extension amplitude (p=0,083) and the function in sports/leisure (p=0,244) were kept through the six-week follow-up. Conclusions: Despite some limitations, this study is of great importance to the community and to the physiotherapists concerned with the growing prevalence of osteoarthritis and the associated costs. Aquatic exercise appears to be an important strategy in the improvement of the health condition of patients who suffer from knee osteoarthritis.

Emove

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

Range of motion measurements based on depth camera for clinical rehabilitation

Dissertação para obtenção do Grau de Mestre em Engenharia Biomédica

A framework for developing motion-based games

Dissertação para obtenção do Grau de Mestre em Engenharia Informática

UAV - based imagery processing using structure from motion and remote sensing technology

With the recent advances in technology and miniaturization of devices such as GPS or IMU, Unmanned Aerial Vehicles became a feasible platform for a Remote Sensing applications. The use of UAVs compared to the conventional aerial platforms provides a set of advantages such as higher spatial resolution of the derived products. UAV - based imagery obtained by a user grade cameras introduces a set of problems which have to be solved, e. g. rotational or angular differences or unknown or insufficiently precise IO and EO camera parameters. In this work, UAV - based imagery of RGB and CIR type was processed using two different workflows based on PhotoScan and VisualSfM software solutions resulting in the DSM and orthophoto products. Feature detection and matching parameters influence on the result quality as well as a processing time was examined and the optimal parameter setup was presented. Products of the both workflows were compared in terms of a quality and a spatial accuracy. Both workflows were compared by presenting the processing times and quality of the results. Finally, the obtained products were used in order to demonstrate vegetation classification. Contribution of the IHS transformations was examined with respect to the classification accuracy.

Frequency-domain receiver design for doubly-selective channels

This work is devoted to the broadband wireless transmission techniques, which are serious candidates to be implemented in future broadband wireless and cellular systems, aiming at providing high and reliable data transmission and concomitantly high mobility. In order to cope with doubly-selective channels, receiver structures based on OFDM and SC-FDE block transmission techniques, are proposed, which allow cost-effective implementations, using FFT-based signal processing. The first subject to be addressed is the impact of the number of multipath components, and the diversity order, on the asymptotic performance of OFDM and SC-FDE, in uncoded and for different channel coding schemes. The obtained results show that the number of relevant separable multipath components is a key element that influences the performance of OFDM and SC-FDE schemes. Then, the improved estimation and detection performance of OFDM-based broadcasting systems, is introduced employing SFN (Single Frequency Network) operation. An initial coarse channel is obtained with resort to low-power training sequences estimation, and an iterative receiver with joint detection and channel estimation is presented. The achieved results have shown very good performance, close to that with perfect channel estimation. The next topic is related to SFN systems, devoting special attention to time-distortion effects inherent to these networks. Typically, the SFN broadcast wireless systems employ OFDM schemes to cope with severely time-dispersive channels. However, frequency errors, due to CFO, compromises the orthogonality between subcarriers. As an alternative approach, the possibility of using SC-FDE schemes (characterized by reduced envelope fluctuations and higher robustness to carrier frequency errors) is evaluated, and a technique, employing joint CFO estimation and compensation over the severe time-distortion effects, is proposed. Finally, broadband mobile wireless systems, in which the relative motion between the transmitter and receiver induces Doppler shift which is different or each propagation path, is considered, depending on the angle of incidence of that path in relation to the direction of travel. This represents a severe impairment in wireless digital communications systems, since that multipath propagation combined with the Doppler effects, lead to drastic and unpredictable fluctuations of the envelope of the received signal, severely affecting the detection performance. The channel variations due this effect are very difficult to estimate and compensate. In this work we propose a set of SC-FDE iterative receivers implementing efficient estimation and tracking techniques. The performance results show that the proposed receivers have very good performance, even in the presence of significant Doppler spread between the different groups of multipath components.

Influence of the wood mechanical properties in the dovetail joint behavior

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.

Behaviour of a dovetail joint solved using force analyses

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.

Learning joint representations for order and timing of perceptual-motor sequences: a dynamic neural field approach

Many of our everyday tasks require the control of the serial order and the timing of component actions. Using the dynamic neural field (DNF) framework, we address the learning of representations that support the performance of precisely time action sequences. In continuation of previous modeling work and robotics implementations, we ask specifically the question how feedback about executed actions might be used by the learning system to fine tune a joint memory representation of the ordinal and the temporal structure which has been initially acquired by observation. The perceptual memory is represented by a self-stabilized, multi-bump activity pattern of neurons encoding instances of a sensory event (e.g., color, position or pitch) which guides sequence learning. The strength of the population representation of each event is a function of elapsed time since sequence onset. We propose and test in simulations a simple learning rule that detects a mismatch between the expected and realized timing of events and adapts the activation strengths in order to compensate for the movement time needed to achieve the desired effect. The simulation results show that the effector-specific memory representation can be robustly recalled. We discuss the impact of the fast, activation-based learning that the DNF framework provides for robotics applications.

Form tutors in the joint teaching of music: perspectives and experiences

In the Portuguese school system, form tutors (FTs) are an intermediate education management structure. The form tutor is responsible for a position of coordination and orientation with a «threefold function»: a relationship with students, relationship with the student’s family and relationship with other class teachers. The joint teaching of music is a part of the educational system in basic education. It is optional and provides musical and instrumental training to students who are interested in taking it. In order to achieve this, there is a system, subject to protocols, between general education schools and schools specializing in teaching music. There is also the position of FT in specialized schools and it also includes a «threefold function». However, these FTs have the additional role of representing music teachers at the class council, which is held at the general education school. Thus, in these cases, both FTs have a fourth joint area, between the music school and the general education school, which makes the relationship between them even more complex. This paper is based on the analysis of empirical data obtained from the testimonies of FTs regarding their representations and experiences in leadership and the coordination of teachers among schools in which there is a joint teaching system. The aim of collecting narratives is to look into some of the main challenges and confrontations related to leadership issues, which we assume to be the focus of those who have the role of form tutor in that specific context.

Estudo do comportamento tribológico de materiais compósitos à base de titânio reforçado com partículas cerâmicas para aplicação em implantes articulares

Dissertação de mestrado integrado em Engenharia Biomédica

A bio-inspired computational model for motion detection

Tese de Doutoramento (Programa Doutoral em Engenharia Biomédica)