Reconhecimento visual de tarjas numéricas de corredores : uma transformada espacial de contornos e cores

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Mecânica, 2018.Este trabalho apresenta uma proposta para detectar os caracteres numéricos, contidos nas tarjas que identificam os atletas corredores de rua, por meio da remodelagem do algoritmo para extração de texto em imagens naturais conhecido como TLC (Transformada de Largura de Curso). A remodelagem proposta, chamada de TLCM (Transformada de Largura de Curso Melhorada), acrescenta novas heurísticas baseadas na verificação da cor em torno dos pixels candidatos a fazerem parte dos caracteres numéricos e também nas características geométricas destes caracteres. Os resultados obtidos ampliaram o índice de detecção dos números em comparação com o algoritmo original e permitiu a criação de um Banco de Dados de imagens de corridas de rua, inédito, e que pode ser usado por qualquer trabalho semelhante.This work presents a proposal to detect the numeric characters contained in the tags that identify the athletes street runners, through the remodeling of the algorithm for extracting text in natural images known as Stroke Width Transform. The proposed remodeling, called ISWT (Improvement Stroke Width Transform), adds new heuristics based on the color check around the candidate pixels to be part of the numerical characters as well as the geometric characteristics of these characters. The results obtained increased the detection rate of the numbers in comparison with the original algorithm and allowed the creation of a database of street racing images, unprecedented, and that can be used for any similar work

Stretch sensors for measuring knee kinematics in sports

The popularity of wearable technology in sport has increased, due to its ability to provide unobtrusive monitoring of athletes. This technology has been used to objectively measure kinetic and kinematic variables, with the aim of preventing injury, maximising athletic performance and classifying the skill level of athletes, all of which can influence training and coaching practices. Wearable technologies overcome the limitations of motion capture systems which are limited in their capture volume, enabling the collection of data in-field, during training and competition. Inertial sensors are a common form of technology used in these environments however, their high-cost and complex calibration due to multiple sensor integration can make them prohibitive for widespread use. This thesis focuses on the development of a strain sensor that can be used to measure knee range of motion in sports, specifically rowing and cycling, as a potential low-cost, lightweight alternative to inertial sensors which can also be integrated into clothing, making them more discreet. A systematic review highlighted the lack of alternate technologies to inertial sensors such as strain sensors, as well as the limited use of wearable technologies in both rowing and cycling. Strain sensors were fabricated from a carbon nanotube-natural rubber composite using solvent exchange techniques and employed a piezoresistive sensing mechanism. These were then characterised using mechanical testing, to determine their electrical properties under cyclical strain. The strain sensors displayed hysteretic behaviour, but were durable, withstanding over 4500 strain cycles. Statistical analysis indicated that over 60% of the tests conducted had good intra-test variability with regards to the resistance response range in each strain cycle and sensor response deviating by less than 10% at strain rates below 100 mm/min and less than 20% at a strain rate of 350 mm/min. These sensors were integrated into a wearable sensor system and tested on rowing and cycling cohorts consisting of ten athletes each, to assess the translational use of the strain sensor. This preliminary testing indicated that strain sensors were able to track the motion of the knee during the rowing stroke and cycling pedalling motion, when compared to the output of a motion capture system. Perspectives of participants on the wearable system were collected, which indicated their desire for a system that they could use in their sport, and they considered the translation of this system for real-life use with further development to improve comfort of the system and consistency of the sensor response. The strain sensors developed in this project, when integrated into a wearable sensor system, have the potential to provide an unobtrusive method of measuring knee kinematics, helping athletes, coaches and other support staff make technical changes that can reduce injury risk and improve performance.Open Acces

Elite rowing : technique and performance

In elite rowing competition the difference between Gold and Silver is often less than one second, and there is a high incidence of injury amongst the sport’s athletes. Previous studies into rowing have described kinetic and kinematic profiles, commented on the effects of factors such as fatigue and training status, and identified some aspects of rowing technique that may be associated with improvements in performance, or with injury mechanisms. However, such work has often been subject to significant errors and limitations, such as: restricting kinematic analysis to two-dimensions, small sample sizes, and lack of clinical and performance relevance. Furthermore there has been no one body of work to date that has published a comprehensive analysis of elite rowers’ technique and described its relevance to performance. This represents a gap in the performance literature. The primary aim of this thesis was to describe and analyse the kinetic output and three-dimensional kinematics of elite rowers. It was hypothesised that a comprehensive and explicit description of athletes’ technique could be compiled, and that aspects of this technique would be influenced by exercise intensity and longitudinal training. Furthermore, it was thought that discrete aspects of technique could be used to predict high levels of athletic performance, and individual’s risk of spinal and knee injuries. A custom experimental methodology was developed and several pilot studies optimised and validated the method. More than eleven hundred rowing trials were completed by members of the Great Britain elite rowing squad over a period of twenty six months. This provided kinetic and kinematic data that was treated and analysed using custom written software, and subjected to statistical modelling. The thesis described the method and kinematic model that was utilised. A detailed description of elite athletes’ rowing technique and kinematics was produced. Increasing exercise intensity influenced some of the measured parameters, and longitudinal feedback, and coaching interventions were effective in influencing the elite participants. Adopting a kyphotic posture in the lumbar region of the spine at any point in the rowing stroke was found to be detrimental to rowing performance, and may be linked to an increased risk of lumbar injury. Rapid extension of the lumbar spine was also thought to pose an injury risk, however it was found that athletes who extended the lumbar spine at the finish of the stroke exhibited better performance than those who did not. The kinematic characteristics of the lower limbs may positively influence rowers’ performance, and provide protection against spinal injury.Open acces

Feeding outcomes in very preterm infants: preliminary effects of positioning

Background/Significance: Oral feeding emerges during a dynamic process of the organization of inputs from subsystems within the infant and the environment. Very preterm infants (VP, ≤ 30 weeks gestational age) are at risk for impaired lung function, which significantly limits their organizational capacity and contributes to feeding difficulties. A head-elevated side-lying (HEL) position has recently been proposed as a strategy that may improve oral feeding in VP infants by supporting breathing during feeding. Purpose: The primary purpose of this study is to test the preliminary effects of the HEL position on the physiologic stability and feeding performance of VP infants when bottle-fed, compared to the head-elevated supine (HES) position. In addition, methods for measuring changes in physiologic stability across the feeding period are examined. Methods: Using a within-subject cross-over design, six VP infants were bottle-fed twice on one day, in both the HEL and HES positions. The following variables were measured before and/or during feeding: physiological stability (heart rate [HR], oxygen saturation [SpO2], respiratory characteristics) and feeding performance (overall milk transfer, proficiency, efficiency, and duration of feeding). Three methods were used to examine changes in physiologic stability across the feeding period. Results: Compared to the HES position, VP infants fed in the HEL position show significantly less variation in HR, less severe and fewer decreases in HR, shorter and more regular intervals between breaths, breathing frequency that is closer to the pre-feeding state, and more variation in breath duration. VP infants also demonstrate a more stable HR over time, especially during the early minutes of feeding, and improved regulated breathing over time by demonstrating shorter and more regular intervals between breaths and more variation in breath duration across the feeding period. In addition, the method using the first 6 minutes of bottle-in period is suggested as the most effective for examining significant changes in physiologic stability over time. No significant findings for SpO2 and feeding performance are found. Conclusions: The findings indicate that the HEL position may be a feeding strategy to support better regulation of breathing during feeding that allows VP infants to better maintain physiologic stability throughout the feeding

The role of common genetic variants for predicting the modulation of cardiovascular outcomes

Attrition is a major issue in the drug development process with 79% of clinical failures due to safety and efficacy concerns. Genetic research can provide supporting evidence of a clear causal relationship between the drug target and disease or reveal unintended effects through associations with non-relevant phenotypes informing on potential drug safety. However, due to the underlying genetic architecture, it is often unclear which gene or variant in the loci identified through genetic analyses is driving the association. Due to recent advancements in CRISPR-Cas9 gene-editing, it is now possible to relatively easily perform whole gene knock-out studies and single base-edits to validate genetic findings of the most likely causal variant and gene. Utilising a combination of genetic approaches and functional studies can provide supporting evidence of the therapeutic profile and potential effects of drug therapies and improve our overall understanding of biological pathways and disease mechanisms. The primary aim of this thesis is to provide genetic data to support the ongoing clinical development of hypoxia-inducible factor (HIF)-prolyl hydroxylase inhibitors (PHIs) for treating anaemia of chronic kidney disease (CKD). Genome-wide association studies (GWAS) were used to identify genetic variants lying within or nearby genes encoding the drug target (prolyl hydroxylase [PHD] enzymes). These identified variants were used in Mendelian Randomisation analysis and phenome-wide association studies to genetically mirror the pharmaceutical effects of PHIs and investigate cardiovascular safety. Functional validation studies were employed to functionally validate a genetic variant for use as a proxy and to obtain a better understanding of the downstream causal pathways and biological mechanisms of the drug target. In summary, this thesis demonstrates how a combination of genetic analyses and functional validation studies is a powerful approach to validate GWAS results and further characterise therapeutic effects. This PhD project identified relevant genetic markers to genetically proxy therapeutic modulation of biomarker levels through PHD inhibition and could potentially inform further research using patient-level clinical data from Phase III trials

California Extremely Large Telescope: Conceptual Design for a Thirty-Meter Telescope

Following great success in the creation of the Keck Observatory, scientists at the California Institute of Technology and the University of California have begun to explore the scientific and technical prospects for a much larger telescope. The Keck telescopes will remain the largest telescopes in the world for a number of years, with many decades of forefront research ahead after that. Though these telescopes have produced dramatic discoveries, it is already clear that even larger telescopes must be built if we are to address some of the most profound questions about our universe. The time required to build a larger telescope is approximately ten years, and the California community is presently well-positioned to begin its design and construction. The same scientists who conceived, led the design, and guided the construction of the Keck Observatory have been intensely engaged in a study of the prospects for an extremely large telescope. Building on our experience with the Keck Observatory, we have concluded that the large telescope is feasible and is within the bounds set by present-day technology. Our reference telescope has a diameter of 30 meters, the largest size we believe can be built with acceptable risk. The project is currently designated the California Extremely Large Telescope (CELT)

Kinematics and Robot Design IV, KaRD2021

This volume collects the papers published on the special issue “Kinematics and Robot Design IV, KaRD2021” (https://www.mdpi.com/journal/robotics/special_issues/KaRD2021), which is the forth edition of the KaRD special-issue series, hosted by the open-access journal “MDPI Robotics”. KaRD series is an open environment where researchers can present their works and discuss all the topics focused on the many aspects that involve kinematics in the design of robotic/automatic systems. Kinematics is so intimately related to the design of robotic/automatic systems that the admitted topics of the KaRD series practically cover all the subjects normally present in well-established international conferences on “mechanisms and robotics”. KaRD2021, after the peer-review process, accepted 12 papers. The accepted papers cover some theoretical and many design/applicative aspects