Mobile robots for rough terrain are of interest to researchers as their range of possible uses is large, including exploration activities for inhospitable areas on Earth and on other planets and bodies in the solar system, searching in disaster sites for survivors, and performing surveillance for military applications. Nature generally achieves land movement by walking using legs, but additional modes such as climbing, jumping and rolling are all produced from legs as well. Robotics tends not to use this integrated approach and adds additional mechanisms to achieve additional movements. The spherical device described within this thesis, called Jollbot, integrated a rolling motion for faster movement over smoother terrain, with a jumping movement for rougher environments. Jollbot was developed over three prototypes. The first achieved pause-and-leap style jumps by slowly storing strain energy within the metal elements of a spherical structure using an internal mechanism to deform the sphere. A jump was produced when this stored energy was rapidly released. The second prototype achieved greater jump heights using a similar structure, and added direction control to each jump by moving its centre of gravity around the polar axis of the sphere. The final prototype successfully combined rolling (at a speed of 0.7 m/s, up 4° slopes, and over 44 mm obstacles) and jumping (0.5 m cleared height), both with direction control, using a 0.6 m spherical spring steel structure. Rolling was achieved by moving the centre of gravity outside of the sphere’s contact area with the ground. Jumping was achieved by deflecting the sphere in a similar method to the first and second prototypes, but through a larger percentage deflection. An evaluation of existing rough terrain robots is made possible through the development of a five-step scoring system that produces a single numerical performance score. The system is used to evaluate the performance of Jollbot.

Standard Markov chain Monte Carlo (MCMC) sampling methods can experience problem sampling from multi-modal distributions. A variety of sampling methods have been introduced to overcome this problem. The mode jumping method of Tjelmeland & Hegstad (2001) tries to find a mode and propose a value from that mode in each mode jumping attempt. This approach is inefficient in that the work needed to find each mode and model the distribution in a neighbourhood of the mode is carried out repeatedly during the sampling process. We shall propose a new mode jumping approach which retains features of the Tjelmeland & Hegstad (2001) method but differs in that it finds the modes in an initial search, then uses this information to jump between modes effectively in the sampling run. Although this approach does not allow a second chance to find modes in the sampling run, we can show that the overall probability of missing a mode in our approach is still low. We apply our methods to sample from distributions which have continuous variables, discrete variables, a mixture of discrete and continuous variables and variable dimension. We show that our methods work well in each case and in general, are better than the MCMC sampling methods commonly used in these cases and also, are better than the Tjelmeland & Hegstad (2001) method in particular.

Este trabalho teve como objetivo avaliar o perfil eletrocardiográfico dos eqüinos praticantes de hipismo clássico em São Paulo e também se estes parâmetros sofrem influências em relação ao tipo de atividade física desempenhada pelo animal (provas de salto abaixo de 1,20 metros e provas acima de 1,20 metros), faixa etária e fatores sexuais. Foram utilizados 100 eqüinos de hipismo clássico, representados por 61 machos e 39 fêmeas, com idades entre 4 e 19 anos. A freqüência cardíaca variou de 18,50 batimentos por minuto (bpm) a 89,45bpm, com média de 40,2077±13,3321, o ritmo cardíaco mais freqüente foi o sinusal com 56%, seguido de taquicardia sinusal 23%, arritmia sinusal 20% e bradicardia sinusal com 1%. As alterações encontradas foram: marcapasso migratório 25%, bloqueio átrio-ventricular de 2°grau (BAV de 2°grau) 9%, BAV de 1°grau 7%, complexos ventriculares prematuros 2% e bloqueio sinoatrial/ \"sinus arrest\" e complexos atrial prematuro com 1%. O eixo elétrico no plano frontal em 87% dos casos esteve entre o e +90 graus. O score cardíaco médio foi de 94,9±16,1milisegundos e em relação à duração na derivação bipolar II, obteve-se onda P com 0,1100±0,0242 segundos, intervalo P-R com 0,3140±0,0744 seg., complexo QRS com 0,0908±0,0250 seg., intervalo QT com 0,4908±0,0536 seg. e onda T com 0,1130±0,0330 seg. Quanto à amplitude também na derivação bipolar II, obteve-se onda P única em 35% dos casos com média de 0,2671±0,0747 milivolts, onda P bifásica em 11% dos eqüinos com média de 0,3136±0,1098mV e onda P bífida em 54% dos animais, sendo esta dividida em porção 1 e 2 (P1 e P2), P1 teve média de 0,1352±0,0492mV e P2 teve média de 0,2259±0,0502mV. A onda R e a onda T estiveram presentes em 100% dos eqüinos obtendo média de 1,0220±0,5028mV e 0,4425±0,2042mV, respectivamente. Quanto à morfologia, considerando-se todas as derivações analisadas, encontraram-se 11 configurações distintas para a onda P e 5 configurações diferentes para o complexo QRS e para a onda T. Segundo as análises estatísticas, houve diferenças significativas na duração, amplitude e morfologia de algumas ondas, intervalos e complexos, em relação ao grupo de atividade física, sexo e idade. / This study aimed to evaluate the electrocardiographic profiles of horses practicing show jumping in São Paulo as well as whether these parameters are affected by kind of physical activity performed by the animal (competitions below 1.20m jumps or above 1.20m), the age level or gender. A hundred show jumping horses were used, being 61 males, and 39 females. Their ages ranged from 4 to 19 years. Heart rate ranged from 18.50 beats per minute (bpm) to 89.45bpm, with an average of 40.2077±13.3321, the most frequent rhythm was sinusal with 56%, followed by sinus tachycardia 23%, sinus arrhythmia 20% and sinus bradycardia 1%. The alterations found were: wandering pacemaker 25%, second-degree atrioventricular block (BAV 2°) 9%, first-degree BAV 7%, ventricular premature complexes 2% and sinoatrial block / sinus arrest as well as premature atrial complexes 1%. The electrical axis at the frontal plane in 87% of the cases was between 0 and +90°. The average cardiac score was 94.9±16.1 milliseconds. In relationship to the bipolar lead II, P wave with 0.1100±0.0242 seconds, P-R interval of 0.3140±0.0744 seconds, QRS complex of 0.0908±0.0250 seconds, QT interval of 0.4908±0.0536 seconds and T wave with 0.1130±0.0330 seconds were obtained. In the amplitude, also at the bipolar lead II a single-peaked P wave was obtained in 35% of the cases with an average of 0.2671±0.0747 millivoltz, biphasic P wave in 11% of horses with an average of 0.3136±0.1098 mV and bifid P wave in 54% of the animals, being the latter divided into portions 1 and 2 (P1 and P2). P1 got an average of 0.1352±0.0492mV and P2 got an average of 0.2259±0.0502 mV. R wave and T wave were present in 100% of the horses, getting an average of 1.0220±0.5028mV and 0.4425±0.2042mV respectively. In relationship to the morphology, considering all the analyzed leads, 11 different configurations for P wave, and 5 different configurations for T wave were observed. According to the statistical investigation, there were significant differences in duration, amplitude and morphology of some waves, intervals and complexes in relationship to the physical activity group, sex and age.

No description available.

This study compared the motor performance of children identified with Developmental Coordination Disorder (DCD) with those of a matched group categorised as typically developing (TD). Based on the existing literature, vertical jumping was the task selected as it is a fundamental movement skill (Gallahue & Ozmun, 2002), and a single optimal coordination pattern has been shown to exist (e.g., Bobbert & van Ingen Schenau, 1998).Within the conceptual framework developed for this enquiry, jump height, the performance outcome, was the highest level variable. Level 2 variables described the centre of mass displacement at key instants during the jumping movement. Level 3 variables identified measures of velocity, force and power, which underpin the movement, and level 4 variables described the countermovement specific to this task. This provided a more thorough analysis than previously reported in DCD literature for jumping. The objective of this study was to identify possible mechanisms of DCD in order to advance the understanding of this impairment. A cross-sectional sample (n = 165) of males and females aged between 5 and 12 years was drawn from a school in Victoria, Australia. Using the Movement–Assessment Battery for Children (M-ABC), 62 children from the sample were identified as having DCD with total impairment scores below the 15th percentile for their age-band (Henderson & Sugden, 1992). From the remaining children assessed, who all scored above the 15th percentile, 62 were matched with the DCD group to form the TD group (n= 62). Participants performed three maximal vertical jumps, standing on a single forceplate. Each child’s best vertical jump was analysed using forceplate (700 Hz) and 2D sagittal kinematic data from a single camera video (50 Hz) capture. The results confirmed previous findings that DCD children jump lower than their TD peers, although there was a considerable overlap in motor ability between the groups. Peak VCOM occurred earlier in the jumping movement in the DCD group, when compared to the TD group. This meant a longer elapsed time from the instant of peak VCOM to take-off, which was attributed to coordination error. The earlier occurrence of peak VCOM in the DCD group could be explained by the lower shank angular velocity at take-off. In addition, the DCD group produced lower jump impulse and peak power. Further probing of the jump height data revealed an interesting relationship between age band and jump height that was gender specific. It was noted that for the DCD males, less than 1% of the variance found in jump height could be accounted for by age-band. In contrast, the explained variance for jump height by age-band was 24% for the TD males. The females showed similar relationships for jump height and age-band in both groups. It was thought that this may reflect physical activity avoidance caused by greater social pressures on boys to be good at sports (e.g., Parker & Larkin, 2003).In addition, a further analysis of the DCD group data was undertaken to compare those who had difficulties in dynamic balance and those who did not. In this analysis, body mass was found to have a significant effect on leg stiffness (Kleg), and when accounted for as a covariate, greater Kleg in the DCD group with dynamic balance difficulties was found. A possible explanation is that for the DCD group with dynamic balance difficulties, the transition from joint flexion to extension during the countermovement was problematic, and resulted in excessive muscle co-activation. This study provides some possible directions for further investigations into coordination issues for DCD children. The time elapsed from peak VCOM to take-off and the shank angular velocities at take-off were identified as key indicators of a poorly coordinated jump. High levels of Kleg reflected difficulties in the transition from joint flexion to extension during the countermovement in those DCD children with dynamic balance problems. Based on these key variables and others that differentiated between groups a more parsimonious conceptual framework is presented. For future enquiry, a more holistic approach for the study of children with such impairments is recommended. This includes exploring the environment these children are exposed to in order to gain a more thorough understanding of practice and learning effects. Understanding of differences in motor ability requires an expanded framework to include information on genetic and socio-cultural factors, and their impact upon important psychology, physical fitness, nutrition, body composition and physical activity parameters.

The purpose of this research was to examine the effects of a premovement silent period (PSP), and an involuntary small amplitude countermovement (CM) on the maximal height of the squat jump (SJ). Fifteen elite male volleyball players (20.6 ± 1.6 yrs) and thirteen untrained males (20.2 ± 1.7 yrs) performed ten maximal effort SJs from identical starting positions. The electromyographic activity of the vastus lateralis and biceps femoris was measured in conjunction with the vertical ground reaction force, and the vertical displacement measured by a cable-extension transducer. The presence of a PSP or small amplitude CM did not increase maximal SJ height significantly (p > 0.05). These findings indicate that in the SJ, facilitation effects of the PSP and small amplitude CM are minimal. This is important to past and future studies utilizing the SJ, as it is often difficult for individuals to perform SJs with no detectable CM. / School of Physical Education

No description available.

Thesis (Ph. D.)--University of Hawaii at Manoa, 1991. / Includes bibliographical references (leaves 199-203). / Microfiche. / xi, 203 leaves, bound ill. 29 cm

Thesis (Ph. D.)--University of California, Riverside, 2009. / Includes abstract. Includes bibliographical references. Issued in print and online. Available via ProQuest Digital Dissertations.

Thesis (M.S.)--Springfield College, 2003. / Includes bibliographical references. Also available online (PDF file) by a subscription to the set or by purchasing the individual file.