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The ability to walk and negotiate stairs is an important predictor of independent ambulation. The superposition of mobility impairments to the effects of natural aging in persons with stroke render the completion of many daily activities unsafe, thus limiting individuals’ independence within their communities. Currently however, no means exist for the monitoring of mobility levels during daily living in survivors after the completion of rehabilitation programs. The application of inertial sensors for stroke survivors could provide a basis for the study of gait outside of traditional laboratory settings. The main objective of this thesis was to evaluate the performance of inertial sensors in measuring gait of hemiparetic stroke survivors through the completion of three studies. The first study explored the use of inertial measurement units (IMUs) for the measurement of lower limb joint kinematics during stair ascent and descent in both stroke survivors and healthy older adults. Results suggested that IMUs were suitable for the measurement of lower limb range of motion in both healthy and post-stroke subjects during stair ambulation. The second study evaluated the measurement of step length and spatial symmetry during overground walking using IMUs. A systematic error resulting in the underestimation of step lengths calculated using IMUs compared with those measured using video analysis was found, however results suggested that IMUs were suitable for the assessment of spatial symmetry between affected and less-affected limbs in stroke survivors. The final study evaluated the automatic classification of gait activities using inertial sensor data. Findings revealed that the use of a classifier composed of frequency-features extracted from IMU accelerometer and gyroscope data from both the affected and less-affected limbs most accurately identified gait activities from post stroke gait data. This thesis provides a first attempt at applying IMUs to the study of gait post-stroke. Future work may extend the findings of these studies to provide a better understanding to rehabilitation professionals of the demands of everyday life for stroke survivors. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2013-08-29 12:42:05.505

The ways that physics students’ conceptualize – the way they experience – the use of algebraic signs in vector-kinematics has not been extensively studied. The most comprehensive of these few studies was carried out in South Africa 15 years ago. This study found that the variation in the ways that students experience the use of algebraic signs could be characterized by five qualitatively different categories. The consistency of the nature of this experience across either the same or different educational settings has never given further consideration. This project sets out to do this using two educational settings; one similar to the original South African one, and one at the natural science preparatory programme known as basåret at Uppsala University in Sweden. The study was carried out under the auspices of the Division of Physics Education Research at the Department of Physics and Astronomy at Uppsala University in collaboration with Nadaraj Govender, University of KwaZulu-Natal, who performed the original study while completing his PhD at the University of the Western Cape, South Africa. This study is situated in the kinematics section of introductory physics with participants drawn from the natural science preparatory programme at Uppsala University and physical science preservice teachers’ programme at the University of KwaZulu-Natal, South Africa. The participating students completed a specially designed questionnaire on the use of signs in kinematics problem solving. A sub-group of these students was also purposefully selected to take part in semi-structured interviews that aimed at further exploring their experiences of algebraic signs. The students’ descriptions and answers were categorized using Nadaraj Govender’s set of categories, which had been constructed using the phenomenographic research approach. This approach is designed to enable finding the variation of ways people experience a phenomenon. The process of sorting the data was grounded in this phenomenographic perspective. From this categorization it was possible to identify four of the original five categories amongst the participating students. The results suggest that these four categories remain educationally relevant today even if the context is not the same as the one for the original findings. Although one of the original five categories was not found, the analysis cannot be taken to definitely eliminate this from the original outcome space of results. A more extensive study would be needed for this and thus a proposal is made that further studies be undertaken around this issue. The study ends by suggesting that physics teachers at the introductory level need to obtain a broader understanding of their students’ difficulties and develop their teaching to better deal with the challenges that become more visible in this broader understanding. / På vilka sätt fysikstudenter föreställer sig och förstår användandet av algebraiska tecken i vektorkinematik har endast studerats i mindre utsträckning. Den mest omfattande av dessa få studier genomfördes i Sydafrika för 15 år sedan. Denna studie upptäckte att variationen av de sätt studenter upplever användandet av algebraiska tecken på kunde karaktäriseras genom fem kvalitativt olika kategorier. Hur solida dessa upplevelser är i en liknande eller helt annan utbildningsmiljö har däremot inte studerats vidare. Detta projekt ämnar till att göra detta genom att använda två olika studentgrupper; en liknande den ursprungliga gruppen i Sydafrika, samt det tekniskt-naturvetenskapliga basåret vid Uppsala universitet, Sverige. Studien har genomförts med stöd från avdelningen för fysikens didaktik vid institutionen för fysik och astronomi vid Uppsala universitet i samarbete med Nadaraj Govender, University of KwaZulu-Natal, Sydafrika, som genomförde den ursprungliga studien under sin doktorandutbildning vid University of the Westen Cape, Sydafrika. Denna studie är begränsad till den del av den grundläggande fysiken som behandlar kinematik och innefattade deltagare från det tekniskt-naturvetenskapliga basåret vid Uppsala universitet samt tredje års studenter vid physical science preservice teachers’ programme, University of KwaZulu-Natal, Sydafrika. De deltagande studenterna genomförde ett specialdesignat frågeformulär kring användandet av algebraiska tecken för att lösa kinematiska problem. En del av dessa studenter valdes sedan ut för att delta i semi-strukturerade intervjuer som syftade till att vidare utforska deras upplevelser kring algebraiska tecken. Studenternas beskrivningar och svar kategoriserades med hjälp av Nadaraj Govenders fem kategorier som tagits fram genom ett fenomenografiskt tillvägagångssätt. Detta tillvägagångssätt är framtaget för att kunna hitta variationen av hur människor upplever ett fenomen. Sorteringsprocessen grundades i detta fenomenografiska perspektiv. Från denna kategorisering var det möjligt att identifiera fyra av de fem ursprungliga kategorierna bland de deltagande studenterna. Fyra av de fem ursprungliga kategorierna som föreslagits av Govender återfanns genom denna studie varför dessa kategorier föreslås förbli relevanta idag även om utbildningsmiljön skiljer sig från den ursprungliga. Trots att den femte kategorin inte hittades kan denna inte definitivt exkluderas från det outcome space som beskriver studenters upplevelser för algebraiska tecken. Det föreslås att vidare studier undersöker förekomsten av denna kategori. Studien avslutas med att föreslå att fysik lärare på grundnivå behöver få en bättre förståelse för sina studenters svårigheter samt att de behöver utveckla sin undervisning för att bättre kunna hantera dessa svårigheter och på så sätt göra undervisningen mer anpassad för mångfalden av studenterna.

Tyrimo objektas – vyrų plaukimo starto atlikimo kinematinių parametrų ypatumai, plaukiant 50 ir 100 m laisvu stiliumi. Darbo tikslas – nustatyti stipriausių Europos plaukikų, plaukiančių 50 ir 100 m laisvuoju stiliumi, starto atlikimo kinematinių parametrų ypatumus 50 m ilgio baseine. Hipotezė – povandeninės starto atkarpos įveikimo ypatumai turi vienodą įtaką jaunių ir suaugusiųjų sportiniams rezultatams, sprinto (50 ir 100 m) laisvuoju stiliumi rungtyje. Tyrimo uždaviniai: 1. Nustatyti stipriausių Europos plaukikų, plaukiančių 50 ir 100 m laisvuoju stiliumi atlikimo kinematinius parametrus 50 m ilgio baseine. 2. Palyginti Europos jaunių ir suaugusiųjų plaukikų, plaukiančių 50 ir 100 m laisvuoju stiliumi starto atlikimo kinematinius parametrus. 3. Nustatyti plaukimo laisvuoju stiliumi starto kinematinių parametrų tarpusavio ir su sportiniu rezultatu sąveiką 50 ir 100 m nuotoliuose. Išvados: 1. Europos jaunių ir suaugusiųjų plaukikų, plaukiančių 50 ir 100 m laisvuoju stiliumi, veiksmų ant bokštelio trukmė, atstumas, įveiktas po vandeniu starto metu patikimai nesiskiria (p > 0,05) 2. Suaugusieji Europos čempionatuose statistiskai reikšmingai pranašesni visuose tirtuose parametruose, išskyrus 50 m laisvu stiliumi povandeninės starto atkarpos ilgį. 3. Povandeninės starto atkarpos įveikimo greitis neigiamai įtakojo abiejų amžiaus grupių starto atkarpos įveikimo greitį 100 m laisvuoju stiliumi rungtyje ir suaugusiųjų 50 m laisvuoju stiliumi rungtyje. / Research object – kinematic parameters features of start performance in 50 and 100 meters freestyle men swimming. Research aim – determine kinematic parameters features of best European swimmers in 50 and 100 meters freestyle swimming. Hypothesis − distance traveled under the water overcoming features has same influence for adult and junior swimmers 50 and 100 meters freestyle swimming. Objectives of the study: 1. Assess kinematic parameters features of best European swimmers in 50 and 100 meters freestyle swimming. 2. Compare kinematic parameters features of best European Adult and Junior swimmers in 50 and 100 meters freestyle swimming. 3. Assess kinematic parameters features interaction between each other and sport results in 50 and 100 meters freestyle swimming. Conclusions: 1. The time that it takes to for the swimmer to leave the block and distance traveled under the water of European Adult and Junior swimmers in 50 and 100 meters freestyle swimming does not differ significantly. 2. Adults of European championship were better and significantly correlated in all researched parameters except distance traveled under water in 50 m freestyle. 3. Distance traveled under water negatively influenced start distance speed of both adults and juniors in 100 meters and adults in 50 meters freestyle swimming.

Located in the Large Magellanic Cloud, R136 is a rare example of a nearby young and dense massive star cluster in which individual stars can be resolved. Often suggested as a globular cluster in formation, its study is of great interest and promises to provide insights into the early dynamical evolution of massive star clusters. This is crucial to understand more extreme and distant starburst clusters, which contribute to a significant fraction of all current star formation in the Local Universe, in particular in interacting galaxies. The majority of this thesis is based on multi-epoch spectroscopic observations in and around R136 obtained as part of the VLT-FLAMES Tarantula Survey (VFTS), an ambitious programme which targeted nearly 1 000 massive stars in the intricate 30 Doradus star-forming region. The motivations and observing strategy of this survey, designed to address key questions about the evolution of massive stars and clusters, are first introduced. The data reduction procedures applied to VFTS data are described, with an emphasis on the tasks accomplished in the context of this thesis. The VFTS data are first used to perform a detailed kinematic study of R136, determine its dynamical state, and evaluate the importance of gas expulsion in the early evolution of massive star clusters. Orbital motions of binary stars are found to dominate the line- of-sight velocity dispersion of the cluster, illustrating the risk of interpreting velocity dispersion measurements for unresolved extragalactic young massive clusters. However, once the detected binaries are rejected and the contribution of undetected binaries is accounted for through Monte Carlo simulations, the true velocity dispersion of the cluster is found to be low and consistent with it being in virial equilibrium. This suggests that gas expulsion has not had a dramatic effect on the early dynamical evolution of R136. Using the velocity measurements of R136 as a test case, a maximum likelihood method that fits the velocity dispersion of a cluster from a single epoch of radial velocity data is then tested. The method must be applied with care given the high binary fraction of massive stars and the large uncertainties in their binary orbital parameter distributions, but for typical velocity dispersions of young massive clusters (& 4 kms−1), it is shown that the velocity dispersion can be measured with an accuracy of 40% or better. This offers an efficient way of constraining the dynamics of these systems. The radial velocity measurements of apparently single stars in R136 are also used to investigate the internal rotation of the cluster, a potentially important but largely unexplored characteristic of young clusters. Evidence is found, at the 95% confidence level, for rotation of the cluster as a whole. A simple maximum likelihood method is presented to fit rotation curves to the data, from which a typical rotational velocity of 3 kms−1 is found. When compared to the low velocity dispersion of R136, this suggests that star clusters may form with as much as 20% of their kinetic energy in rotation. Finally, a smaller-scale survey of massive stars in the Wing of the Small Magellanic Cloud is introduced. As an example of the particularly interesting massive binaries that can be revealed by the synergy between large optical spectroscopic surveys of young clusters and observations at other wavelengths, the discovery of a new Be/X-ray pulsar binary and associated supernova remnant is reported. With a long spin period of over 1 000 seconds and a young age of 104 years constrained by its association with the supernova remnant, the pulsar in this system is quickly emerging as a unique object that challenges our understanding of the spin evolution of accreting neutron stars.

We present a recalibration of the M-BH-sigma(star) relation, based on a sample of 16 reverberation-mapped galaxies with newly determined bulge stellar velocity dispersions (sigma(star)) from integral-field spectroscopy (IFS), and a sample of 32 quiescent galaxies with publicly available IFS. For both samples, sigma(star) is determined via two different methods that are popular in the literature, and we provide fits for each sample based on both sets of sigma(star). We find the fit to the active galactic nucleus sample is shallower than the fit to the quiescent galaxy sample, and that the slopes for each sample are in agreement with previous investigations. However, the intercepts to the quiescent galaxy relations are notably higher than those found in previous studies, due to the systematically lower sigma(star) measurements that we obtain from IFS. We find that this may be driven, in part, by poorly constrained measurements of bulge effective radius (r(e)) for the quiescent galaxy sample, which may bias the sigma(star) measurements low. We use these quiescent galaxy parameterizations, as well as one from the literature, to recalculate the virial scaling factor f. We assess the potential biases in each measurement, and suggest f = 4.82 +/- 1.67 as the best currently available estimate. However, we caution that the details of how sigma(star) is measured can significantly affect f, and there is still much room for improvement.

Redundant manipulators are widely used because they have a greater dexterity andversatility than nonredundant manipulators. In the redundant manipulators, thenumber of degrees of freedom are more than the required to manipulate objects atthe task space, which leads to a possibility to generate infinite number of solutions.For this reasons it has been a hot research topic to exploit the redundancy. Thisthesis work is focus on modeling and controlling redundant robot manipulator withseven degree of freedom (LWA 10 kg payload by Schunk). A literature review hasbeen prepared on the existing methods of exploiting the redundancy in the 7-DOFmanipulators at the velocity and position levels. The forward kinematic equationsare derived using the Denavit-Hartenberg method. The inverse kinematic problem issolved and the redundancy is exploited at the position level to avoid the computationalcomplexity and inaccuracy associated with exploiting the redundancy at the velocitylevel. The joint angles of the manipulator are computed in term of a redundancyparameter defining the self-motion in the manipulator. The relation between the jointangles and the redundancy parameter is exploited to avoid selecting the arm anglesthat violate the joint limits. The singularity configurations and robot workspace arealso studied in this thesis. An example is presented on how the self-motion of thearm appears when the end-effector is stationary. The methods are applied to followstraight line trajectories while preventing the joints to exceed the limits. The resultsfound showed how exploiting the redundancy at the position level is being exact withlow computational cost. The validity of the methods is verified by Robotics Toolboxsimulations.

Stars form when filaments and dense cores in molecular clouds fragment and collapse due to self-gravity. In the most basic analyses of gravitational stability, the competition between self-gravity and thermal pressure sets the critical (i.e. maximum stable) mass of spheres and the critical line density of cylinders. Previous work has considered additional support from magnetic fields and turbulence. Here, we consider the effects of non-ionizing radiation, specifically the inward radiation pressure force that acts on dense structures embedded in an isotropic radiation field. Using hydrostatic, isothermal models, we find that irradiation lowers the critical mass and line density for gravitational collapse, and can thus act as a trigger for star formation. For structures with moderate central densities, similar to 10(3) cm(-3), the interstellar radiation field in the Solar vicinity has an order unity effect on stability thresholds. For more evolved objects with higher central densities, a significant lowering of stability thresholds requires stronger irradiation, as can be found closer to the Galactic centre or near stellar associations. Even when strong sources of ionizing radiation are absent or extincted, our study shows that interstellar irradiation can significantly influence the star formation process.

M.Ing. / This study describes a new class of mechanism to provide leg like motion, for use in a new type of walking machine, that is larger and simpler than electromechanical machines that are currently available. The mechanism is located in a historic context, and current technology in this area is reviewed. The problem of calculating the geometry of the complex mechanism is solved using an innovative solution based on coordinate geometry, which may be extended to solve other planar mechanisms of either greater or lesser complexity. All assumptions have been detailed. The analysis covers both the motion and the power requirements required to make the mechanism move. Structural aspects, which may affect any practical walking machine, are covered. A software implementation has been developed, providing output to demonstrate that the model developed reflects reality, within the limits of the assumptions made.