Tracking scapular movement

Measuring the three-dimensional movement of the scapula provides vital information in the analysis and treatment of shoulder clinical disorders and contributes to our understanding of its complex kinematics. However, the thick layer of skin overlying the scapular region means that all skin-based techniques inaccurately determine the scapular kinematics. The scapula locator makes use of a palpation technique in order to reduce the problem of skin deformation. At present, the scapula locator is the most accurate noninvasive method of measuring scapular movements, but to date the method has only been used to measure the scapula position statically. Here, a new method was developed to measure the scapula movements dynamically; the method makes use of the scapula locator and feedback from pressure-sensors attached to the locator probes to track the scapula during movement. The reliability of the method after short-term practise as well as the intra-observer and inter-observer variations and the inter-session repeatability were tested and quantified in a series of studies. The method was found to be able to measure dynamic scapular movements in slow to medium paced arm movements to a good degree of accuracy as well as provide scapulothoracic measurements of high reliability compared to using the scapula locator on its own and to previously reported results in the literature. Finally, the new locator method was used to calibrate the acromial tracker in order to improve the accuracy of the device and facilitate its use as an alternative to the scapula locator in clinical studies involving fast (higher than functional velocities) dynamic activities. The new scapula locator method and the calibrated acromial tracker method present significant improvements on the available scapular measurement techniques particularly in measuring subtle scapular rotations of clinical importance, such as the scapular tilt. The methods described will be used in future clinical and sport-related studies

GyroWheel™ - An Innovative New Actuator/Sensor for 3-axis Spacecraft Attitude Control

The Bristol Gyro Wheel is an innovative attitude control system device that provides both an angular momentum bias and control torques about three axes while at the same time measuring the spacecraft angular rates about two axes. The principles of operation of this device are explained and the flight model design is described that is targeted at small satellite applications which is currently under development. A fully functional prototype of the GyroWheel has been developed that has demonstrated the actuator and rate sensing capabilities and some of the test results are given. One of the key advantages of the Gyro Wheel is that, for earth pointing applications, it can be used with a single 2- axis earth sensor to provide fine pointing control in all three axes. This allows for reducing the mass, power above all cost of this class of ACS system. A Gyro Wheel based ACS design is developed for an example case consisting of a small earth pointing microsat mission. Performance simulations are given that show that the pointing control can be maintained within 0.1 degrees in all axes. The Gyro Wheel promises to fulfill the need for low cost, low mass, high reliability and high accuracy attitude control systems for applications such as communications, remote sensing, and space science

Assistente de navegação com apontador laser para conduzir cadeiras de rodas robotizadas

Orientador: Eric RohmerDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de ComputaçãoResumo: As soluções de robótica assistida ajudam as pessoas a recuperar sua mobilidade e autonomia perdidas em suas vidas diárias. Este documento apresenta um assistente de navegação de baixo custo projetado para pessoas tetraplégicas para dirigir uma cadeira de rodas robotizada usando a combinação da orientação da cabeça e expressões faciais (sorriso e sobrancelhas para cima) para enviar comandos para a cadeira. O assistente fornece dois modos de navegação: manual e semi-autônomo. Na navegação manual, uma webcam normal com o algoritmo OpenFace detecta a orientação da cabeça do usuário e expressões faciais (sorriso, sobrancelhas para cima) para compor comandos e atuar diretamente nos movimentos da cadeira de rodas (parar, ir à frente, virar à direita, virar à esquerda). No modo semi-autônomo, o usuário controla um laser pan-tilt com a cabeça para apontar o destino desejado no solo e valida com o comando sobrancelhas para cima que faz com que a cadeira de rodas robotizada realize uma rotação seguida de um deslocamento linear para o alvo escolhido. Embora o assistente precise de melhorias, os resultados mostraram que essa solução pode ser uma tecnologia promissora para pessoas paralisadas do pescoço para controlar uma cadeira de rodas robotizadaAbstract: Assistive robotics solutions help people to recover their lost mobility and autonomy in their daily life. This document presents a low-cost navigation assistant designed for people paralyzed from down the neck to drive a robotized wheelchair using the combination of the head's posture and facial expressions (smile and eyebrows up) to send commands to the chair. The assistant provides two navigation modes: manual and semi-autonomous. In the manual navigation, a regular webcam with the OpenFace algorithm detects the user's head orientation and facial expressions (smile, eyebrows up) to compose commands and actuate directly on the wheelchair movements (stop, go front, turn right, turn left). In the semi-autonomous, the user controls a pan-tilt laser with his/her head to point the desired destination on the ground and validates with eyebrows up command which makes the robotized wheelchair performs a rotation followed by a linear displacement to the chosen target. Although the assistant need improvements, results have shown that this solution may be a promising technology for people paralyzed from down the neck to control a robotized wheelchairMestradoEngenharia de ComputaçãoMestre em Engenharia ElétricaCAPE

A theoretical and experimental analysis of adaption to asymmetrical and distorted visual stimulation

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Development of an anatomical landmark protocol for constructing segment axes for lower extremity kinematic analysis

"The objective of this study was to determine whether a landmark protocol could reliably gather more anatomically accurate data than the default software setting for an electromagnetic tracking system. Nineteen healthy participants (10 males, 9 females) were measured clinically for pelvic angle (deg), tibiofemoral angle (deg), and navicular drop (mm) and compared to kinematic variables of transverse knee angle, frontal plane knee valgus/varus angle, and sagittal plane pelvic angle obtained from both the default and landmark digitization protocols (counterbalanced). Day-to-day reliability for both digitization protocols ranged from an ICC of -0.44(9.5 degrees) to 0.72(2.3 degrees). Kinematic values obtained from the landmark protocol were generally larger and more variable than those obtained from the default setting, and tended to correlate better with the clinical measures of anatomical alignment. While further study is needed, the landmark protocol shows promise as a method for collecting kinematic data that more closely approximates anatomical alignment of the lower extremity."--Abstract from author supplied metadata

Nomadic input on mobile devices: the influence of touch input technique and walking speed on performance and offset modeling

In everyday life people use their mobile phones on-the-go with different walking speeds and with different touch input techniques. Unfortunately, much of the published research in mobile interaction does not quantify the influence of these variables. In this paper, we analyze the influence of walking speed, gait pattern and input techniques on commonly used performance parameters like error rate, accuracy and tapping speed, and we compare the results to the static condition. We examine the influence of these factors on the machine learned offset model used to correct user input and we make design recommendations. The results show that all performance parameters degraded when the subject started to move, for all input techniques. Index finger pointing techniques demonstrated overall better performance compared to thumb-pointing techniques. The influence of gait phase on tap event likelihood and accuracy was demonstrated for all input techniques and all walking speeds. Finally, it was shown that the offset model built on static data did not perform as well as models inferred from dynamic data, which indicates the speed-specific nature of the models. Also, models identified using specific input techniques did not perform well when tested in other conditions, demonstrating the limited validity of offset models to a particular input technique. The model was therefore calibrated using data recorded with the appropriate input technique, at 75% of preferred walking speed, which is the speed to which users spontaneously slow down when they use a mobile device and which presents a tradeoff between accuracy and usability. This led to an increase in accuracy compared to models built on static data. The error rate was reduced between 0.05% and 5.3% for landscape-based methods and between 5.3% and 11.9% for portrait-based methods

Shoulder morphofunctional adaptations on overhead-throwing athletes : implications for physiotherapy throwing-shoulder examination.

Doutoramento em Motricidade Humana, especialidade de Ciências da Fisioterapia.The overhead throwing motion is a highly skilled movement, particularly demanding to the shoulder due to high strength levels and/or acceleration applied to the hand and by the elevated degree of control and precision required to position the arm in space. The shoulders of those involved in repeated forceful overhead throwing, the overhead-throwing athletes, undergo a range of neural, soft tissues and skeletal adaptations that could be described as, the “overhead-throwing shoulder adaptive pattern” (OTSAP). The main goal of overall studies in this thesis was to characterize the dominant overhead-throwing shoulder adaptive pattern of non-symptomatic overhead throwing athletes, comparing with a non-athletic population. Additionally, while comparing volleyball and team-handball players, we looked for specific sport-related components of the OTSAP. Knowledge on OTSAP is important for those involved on training, but also for sport physiotherapist during shoulder functional assessment. Some components of the OTSAP could be mistaken by injury signs or risk factors. Structural (osseous) and functional changes were identified on the dominant shoulder of volleyball and team-handball players. Some were similar of those described in baseball players, and others were sport-related. Thus, the OTSAP should be considered by the physiotherapist during overhead-throwing shoulder assessment. RESUMO:O movimento de lançamento é altamente especializado e particularmente exigente para o ombro devido aos excessivos níveis de carga/aceleração aplicados. Atletas cujos ombros estão envolvidos em movimentos repetidos de lançamento, consideram-se, na literatura anglo-saxónica, atletas “overhead”. Estes são sujeitos a um conjunto de adaptações neurais, tecidulares e ósseas que podem ser descritas como, o “padrão de adaptação do ombro do atleta overhead” (PAOAO). O principal objetivo da tese foi caracterizar o padrão de adaptação do ombro dominante, não sintomático, dos atletas “overhead”, comparando-os com não atletas. Adicionalmente, comparando voleibolistas e andebolistas, procurou-se encontrar componentes específicos da modalidade praticada inerentes ao PAOAO. O conhecimento detalhado deste PAOAO é crucial para os intervenientes em processos de treino, e para o fisioterapeuta responsável por uma avaliação detalhada do ombro, sob pena de alguns dos componentes do PAOAO serem erroneamente considerados como sinais de lesão ou fatores de risco. Foram identificadas alterações estruturais e funcionais no ombro dominante de voleibolistas e andebolistas. Algumas são similares às encontradas em jogadores de beisebol, enquanto outras estão diretamente relacionadas com a prática desportiva específica. Assim, este PAOAO deverá ser tido em consideração pelo fisioterapeuta aquando da avaliação do ombro do atleta “overhead”.FCT - Fundação para a Ciência e a Tecnologi

Ability-Based Methods for Personalized Keyboard Generation

This study introduces an ability-based method for personalized keyboard generation, wherein an individual's own movement and human-computer interaction data are used to automatically compute a personalized virtual keyboard layout. Our approach integrates a multidirectional point-select task to characterize cursor control over time, distance, and direction. The characterization is automatically employed to develop a computationally efficient keyboard layout that prioritizes each user's movement abilities through capturing directional constraints and preferences. We evaluated our approach in a study involving 16 participants using inertial sensing and facial electromyography as an access method, resulting in significantly increased communication rates using the personalized keyboard (52.0 bits/min) when compared to a generically optimized keyboard (47.9 bits/min). Our results demonstrate the ability to effectively characterize an individual's movement abilities to design a personalized keyboard for improved communication. This work underscores the importance of integrating a user's motor abilities when designing virtual interfaces.Comment: 20 pages, 7 figure

Assessment of Audio Interfaces for use in Smartphone Based Spatial Learning Systems for the Blind

Recent advancements in the field of indoor positioning and mobile computing promise development of smart phone based indoor navigation systems. Currently, the preliminary implementations of such systems only use visual interfaces—meaning that they are inaccessible to blind and low vision users. According to the World Health Organization, about 39 million people in the world are blind. This necessitates the need for development and evaluation of non-visual interfaces for indoor navigation systems that support safe and efficient spatial learning and navigation behavior. This thesis research has empirically evaluated several different approaches through which spatial information about the environment can be conveyed through audio. In the first experiment, blindfolded participants standing at an origin in a lab learned the distance and azimuth of target objects that were specified by four audio modes. The first three modes were perceptual interfaces and did not require cognitive mediation on the part of the user. The fourth mode was a non-perceptual mode where object descriptions were given via spatial language using clockface angles. After learning the targets through the four modes, the participants spatially updated the position of the targets and localized them by walking to each of them from two indirect waypoints. The results also indicate hand motion triggered mode to be better than the head motion triggered mode and comparable to auditory snapshot. In the second experiment, blindfolded participants learned target object arrays with two spatial audio modes and a visual mode. In the first mode, head tracking was enabled, whereas in the second mode hand tracking was enabled. In the third mode, serving as a control, the participants were allowed to learn the targets visually. We again compared spatial updating performance with these modes and found no significant performance differences between modes. These results indicate that we can develop 3D audio interfaces on sensor rich off the shelf smartphone devices, without the need of expensive head tracking hardware. Finally, a third study, evaluated room layout learning performance by blindfolded participants with an android smartphone. Three perceptual and one non-perceptual mode were tested for cognitive map development. As expected the perceptual interfaces performed significantly better than the non-perceptual language based mode in an allocentric pointing judgment and in overall subjective rating. In sum, the perceptual interfaces led to better spatial learning performance and higher user ratings. Also there is no significant difference in a cognitive map developed through spatial audio based on tracking user’s head or hand. These results have important implications as they support development of accessible perceptually driven interfaces for smartphones