Dissertations / Theses: 'Body accelerations'

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Bleakley, Steven Shea, and steven bleakley@qr com au. "Time Frequency Analysis of Railway Wagon Body Accelerations for a Low-Power Autonomous Device." Central Queensland University, 2006. http://library-resources.cqu.edu.au./thesis/adt-QCQU/public/adt-QCQU20070622.121515.

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This thesis examines the application of the techniques of Fourier spectrogram and wavelet analysis to a low power embedded microprocessor application in a novel railway and rollingstock monitoring system. The safe and cost effective operation of freight railways is limited by the dynamic performance of wagons running on track. A monitoring system has been proposed comprising of low cost wireless sensing devices, dubbed Health Cards, to be installed on every wagon in the fleet. When marshalled into a train, the devices would sense accelerations and communicate via radio network to a master system in the locomotive. The integrated system would provide online information for decision support systems. Data throughput was heavily restricted by the network architecture, so significant signal analysis was required at the device level. An electronics engineering team at Central Queensland University developed a prototype Health Card, incorporating a 27MHz microcontroller and four dual axis accelerometers. A sensing arrangement and online analysis algorithms were required to detect and categorise dynamic events while operating within the constraints of the system. Time-frequency analysis reveals the time varying frequency content of signals, making it suitable to detect and characterise transient events. With efficient algorithms such as the Fast Fourier Transform, and Fast Wavelet Transform, time-frequency analysis methods can be implemented on a low power, embedded microcontroller. This thesis examines the application of time-frequency analysis techniques to wagon body acceleration signals, for the purpose of detecting poor dynamic performance of the wagon-track system. The Fourier spectrogram is implemented on the Health Card prototype and demonstrated in the laboratory. The research and algorithms provide a foundation for ongoing development as resources become available for system testing and validation.

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Buckley, Christopher. "Upper body accelerations as a biomarker of gait impairment in the early stages of Parkinson's disease." Thesis, University of Sheffield, 2017. http://etheses.whiterose.ac.uk/19779/.

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Neurodegenerative diseases such as Parkinson's disease (PD) impair the ability to walk safely and efficiently. Currently, clinical rating scales designed to assess gait are often described to be subjective and lacking sensitivity to detect gait impairments at the early stage of the disease. Devices are available to objectively measure gait within research laboratories; however, they are often expensive and require trained expertise. Inertial measurement units (IMUs) may be an ideal device to measure gait while overcoming many of the limitations of other devices. They can measure movements of the upper body, which in PD is known to be impaired, and therefore may enable the calculation of a variety of acceleration based variables better capable to quantify impaired gait in PD. This thesis aimed to determine the ability of a variety of acceleration based variables obtained from different location of the upper body to detect movements symptomatic to PD from age matched controls. Variables yet to be applied to PD were tested and methodological reasons for why differing results found in the literature was analysed, in an attempt to develop a refined methodology specific to PD. Acceleration based variables were tested relative to, and combined with, variables obtained from a 7m pressure sensitive mat. It was tested whether these variables bring additional information about a patient's gait or if they are merely a reflection of lower limb mechanics, and, whether they can classify PD gait independently or in combination with a pre-existing spatiotemporal model of gait. Results showed that for a large population of people with early stage PD, upper body acceleration variables not previously applied to PD were capable to highlight gait impairments. However, attention must be made to the processing of the acceleration signals as the method used to realign signals to a global reference can significantly impact a variable's sensitivity to PD. Lastly, it was shown that the majority of upper body acceleration variables are unique from typically measured spatiotemporal information, and when using a multivariate approach, were equally capable to highlight gait impairment in PD. This thesis therefore proposes that variables calculated from the upper body using IMUs can be useful biomarkers of gait impairment at the early stage of PD, and if possible, should be used in conjunction with traditional approaches.

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Crompton, Francis Benedict. "Aerobatics and body size in the midge Chironomus plumosus L." Thesis, University of Newcastle Upon Tyne, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.289177.

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Kejonen, P. (Pirjo). "Body movements during postural stabilization:measurements with a motion analysis system." Doctoral thesis, University of Oulu, 2002. http://urn.fi/urn:isbn:9514267931.

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Abstract Good postural stability is needed during most activities in daily life. Balance can be improved with specific training programmes in physiotherapy. The goals of treatment differ, depending on the subject's age and disorders. In clinical practice, postural stability is commonly evaluated by scaled functional tests or by recording body sway on a platform. On the basis of therapeutic modalities, information of separate movements of body segments would be important. The data might be useful in developing balance evaluation and training programmes in physiotherapy. The aim of this project was to present one method and to estimate its reliability and validity in studying the movements of separate body segments in postural control. In addition, the association between age, gender and anthropometric factors and the movements of separate body segments during quiet stance with the eyes open and closed were studied in a group of healthy subjects. A method was developed to measure the body movements during standing with a motion analysis system, and the reliability of body movement measurements was evaluated. The validity of the motion analysis measurements was evaluated to compare the balancing body measurements during stance on two legs and on one leg obtained with a motion analysis system and a platform. In cross-sectional studies, 100 healthy randomly selected subjects were stratified into ten groups (by age and gender). The body movements of all subjects standing on two legs with the eyes open and closed were measured using a motion analysis system and calculated as maximal and total movements. The movement velocities and accelerations were analysed and compared between the eyes open and eyes closed conditions. The associations between movement values and age and gender were analysed. In addition, the body anthropometrics of the subjects were measured and the relations between the body characteristics and the body balancing movements were calculated using regression analysis. The results showed that motion analysis can be used in measuring body movements in postural stability. Better reproducible balance measurement results are obtained with the total movement values than with the maximal amplitude values. In a comparison of the parameters used in a validity study, motion analysis and platform seemed to reflect the same aspect of balance, although the views of measurement were different. During standing on two legs with the eyes open, there was a statistically significant difference in the maximal anterior-posterior head movement and in the vertical navel movement between the age groups, but the results did not show other statistically significant differences between the balancing movements of separate body segments of the groups or between the balance measurement values of men and women in standing on two legs with the eyes open and closed. It seems that healthy female and male subjects control their stance with quite similar ranges of body adjustment. Body characteristics had slight but considerable effects on the variations of body balancing movements in standing on two legs with the eyes open, but almost none in the eyes-closed conditions. There were differences in the results between the male and female groups. In standing on two legs with the eyes closed, all the measured body parts except the ankles had significantly higher maximal velocity and acceleration values than in standing with the eyes open. The effect of visual information on balancing the body seems to be essential. The results indicated that the motion analysis system is also a useful tool in further balance studies, but the methods of analysis need to be developed. Postural stability should be evaluated and practised even in more demanding balance performances. Movement speed and the special role of each body part in maintaining balance should be paid attention.

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Serravite, Daniel H. "Whole Body Periodic Acceleration Reduces Levels of Delayed Onset Muscle Soreness After Eccentric Exercise." Scholarly Repository, 2010. http://scholarlyrepository.miami.edu/oa_dissertations/650.

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Context: Several recovery strategies have been used, with limited effectiveness, to reduce the muscle discomfort or pain and the diminished muscle performance following a bout of unaccustomed physical activity, a condition known as delayed onset of muscle soreness (DOMS). Muscle damage in this condition is associated with mechanical disruption of the muscle and connective tissue and inflammation and increased oxidative stress. Low frequency, low intensity, whole body periodic acceleration (WBPA) that increases nitric oxide (NO) release from vascular endothelium into the circulation through increased pulsatile shear stress offers a potential solution. This is because endothelial derived nitric oxide has anti-inflammatory, antioxidant and anti-nociceptive properties. Objective: The purpose of this study was to examine the effects of WBPA on the pain and diminished muscle performance associated with DOMS induced by unaccustomed eccentric arm exercise in young male subjects. Design: Longitudinal. Setting: University Exercise Physiology Laboratory. Participants: Seventeen active men, 23.4 +/- 4.6 yr of age. Intervention: Subjects made six visits to the research facility over a two-week period. On day one, the subject performed a 1RM elbow flexion test and was then randomly assigned to the WBPA or control group. Criterion measurements were taken on Day 2, prior to and immediately following performance of the eccentric exercise protocol (10 sets of 10 repetitions using 120% of 1RM) and after the recovery period. During all subsequent sessions (24, 48, 72, and 96 h) these data were collected before the WBPA or passive recovery was provided. Main Outcome Measures: Isometric strength (MVC), blood markers (CPK, MYO, IL-6, TNF-alpha and Uric Acid), soreness, pain, circumference, and range of motion (ROM). Results: Significantly higher MVC values were seen for the WBPA group across the entire 96 h recovery period. Additionally, within group differences were seen in CPK, MYO, IL-6, soreness, pain, circumference, and ROM showing a smaller impact and more rapid recovery by the WBPA group. Conclusion: Application of WBPA hastens recovery from DOMS after eccentric exercise. Given the lack of other potential mechanisms, these effects appear to be mediated by the increased NO release with WBPA.

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MARTÍN, DE AZCÁRATE LAURA. "Muscle contributions to body mass center acceleration during the first stance of sprint running." Thesis, KTH, Mekanik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-250027.

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The best results in a sprint running are based upon covering the distance in the shortest possible time, and therefore performance has to be maximized. To achieve the best performance, the sprinter has to develop the greatest forward acceleration, reach his/her maximal speed, and keep it over the run. The greatest anteroposterior acceleration is generated in the first stance of a sprint due to the greatest propulsive force production. Thus, the first step was selected to study induced accelerations by the main muscles of the lower limb. Since a wider step width was founded out to help with force generation during long foot-ground contacts, an elite sprinter with a wide step width was selected. Ankle plantarflexors were the main contributors to body propulsion and support, while knee extensors decelerated forward propulsion but induced medial accelerations. Hip extensors and hip adductors did not offer a remarkable contribution to body COM acceleration in any direction.

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McErlain-Naylor, Stuart A. "The effect of joint compliance within rigid whole-body computer simulations of impacts." Thesis, Loughborough University, 2017. https://dspace.lboro.ac.uk/2134/33495.

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In high impact human activities, much of the impact shock wave is dissipated through internal body structures, preventing excessive accelerations from reaching vital organs. Mechanisms responsible for this attenuation, including lower limb joint compression and spinal compression have been neglected in existing whole-body simulation models. Accelerometer data on one male subject during drop landings and drop jumps from four heights revealed that peak resultant acceleration tended to decrease with increasing height in the body. Power spectra contained two major components, corresponding to the active voluntary movement (2 Hz 14 Hz) and the impact shock wave (16 Hz 26 Hz). Transfer functions demonstrated progressive attenuation from the MTP joint towards the C6 vertebra within the 16 Hz 26 Hz component. This observed attenuation within the spine and lower-limb joint structures was considered within a rigid body, nine-segment planar torque-driven computer simulation model of drop jumping. Joints at the ankle, knee, hip, shoulder, and mid-trunk were modelled as non-linear spring-dampers. Wobbling masses were included at the shank, thigh, and trunk, with subject-specific biarticular torque generators for ankle plantar flexion, and knee and hip flexion and extension. The overall root mean square difference in kinetic and kinematic time-histories between the model and experimental drop jump performance was 3.7%, including ground reaction force root mean square differences of 5.1%. All viscoelastic displacements were within realistic bounds determined experimentally or from the literature. For an equivalent rigid model representative of traditional frictionless pin joint simulation models but with realistic wobbling mass and foot-ground compliance, the overall kinetic and kinematic difference was 11.0%, including ground reaction force root mean square differences of 12.1%. Thus, the incorporation of viscoelastic elements at key joints enables accurate replication of experimentally recorded ground reaction forces within realistic whole-body kinematics and removes the previous need for excessively compliant wobbling masses and/or foot-ground interfaces. This is also necessary in cases where shock wave transmission within the simulation model must be non-instantaneous.

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Eastman, Carie Suzanne. "Effect of High-Speed Treadmill Training with a Body Weight Support System in a Sport Acceleration Program." BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/2739.

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Introduction: Maximum running acceleration essential components in many sports. The identification of specific training protocols to maximize sprint speed would be useful knowledge for soccer coaches and players. Purpose: The purpose of this study was to determine the effect of a high-speed treadmill with the use of a body-weight support system in a 6-week sport acceleration program on: 40-yard sprint time, maximal isometric knee flexor and extensor strength. Methods: 32 female soccer players (age 16 ± 1.19 yrs) participated in two treatment groups and one control group. Both treatment groups participated in a 12-session sport acceleration program. The first treatment group utilized a body-weight support system while on a high-speed treadmill; the second group used a standard treadmill with no body weight support system. The control group, NT, did not participate in a sports acceleration program and did not alter their exercise routines outside of the study. Results: For each variable an Analysis of Covariance (ANCOVA) was performed. 40-yard sprint times for treatment groups were shown to improve significantly as compared to the control group (p = 0.0007 for high-speed treadmill with body-weight support system, p= < 0.0001 for standard treadmill without body-weight support system). Isometric flexor and extensor strengths did not show significant differences between treatment groups and control group. P-values for the high-speed with body-weight support system were (p = 0.53) for flexors and (p = 0.51) for extensors as compared to the control group. P-values for the standard treadmill with no body-weight support system were (p = 0.19) for extensors and (p = 0.0263) for flexors. It is noted that the extensor muscles were nearly significant for the standard treadmill with no body-weight support system. Discussion: These results can help high school coaches and athletes determine the optimal treadmill training regime. The current study shows that a high-speed treadmill with body-weight support system is just as beneficial as standard treadmill training.

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Lathan, Corinna E. (Corinna Elisabeth). "Human eye movements in response to linear optokinetic stimulation and whole-body acceleration, and the effects of spaceflight." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/11653.

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Bin, Hammam Ghassan Mohammed. "Whole-Body Motion Retargeting for Humanoids." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1408367811.

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Miwa, Masafumi. "Estimation of energy expenditure of grazing ruminants via accelerometry." 京都大学 (Kyoto University), 2017. http://hdl.handle.net/2433/225658.

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Kyoto University (京都大学) 0048 新制・課程博士 博士(農学) 甲第20433号 農博第2218号 新制||農||1048(附属図書館) 学位論文||H29||N5054(農学部図書室) 京都大学大学院農学研究科応用生物科学専攻 (主査)教授廣岡博之, 教授久米新一, 教授今井裕 学位規則第4条第1項該当

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Gautam, Ishwor. "Quaternion based attitude estimation technique involving the extended Kalman filter." University of Akron / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=akron1556196539847396.

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Tollefson, Mallory RaNae. "Accelerated many-body protein side-chain repacking using gpus: application to proteins implicated in hearing loss." Thesis, University of Iowa, 2017. https://ir.uiowa.edu/etd/6006.

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With recent advances and cost reductions in next generation sequencing (NGS), the amount of genetic sequence data is increasing rapidly. However, before patient specific genetic information reaches its full potential to advance clinical diagnostics, the immense degree of genetic heterogeneity that contributes to human disease must be more fully understood. For example, although large numbers of genetic variations are discovered during clinical use of NGS, annotating and understanding the impact of such coding variations on protein phenotype remains a bottleneck (i.e. what is the molecular mechanism behind deafness phenotypes). Fortunately, computational methods are emerging that can be used to efficiently study protein coding variants, and thereby overcome the bottleneck brought on by rapid adoption of clinical sequencing. To study proteins via physics-based computational algorithms, high-quality 3D structural models are essential. These protein models can be obtained using a variety of numerical optimization methods that operate on physics-based potential energy functions. Accurate protein structures serve as input to downstream variation analysis algorithms. In this work, we applied a novel amino acid side-chain optimization algorithm, which operated on an advanced model of atomic interactions (i.e. the AMOEBA polarizable force field), to a set of 164 protein structural models implicated in deafness. The resulting models were evaluated with the MolProbity structure validation tool. MolProbity “scores” were originally calibrated to predict the quality of X-ray diffraction data used to generate a given protein model (i.e. a 1.0 Å or lower MolProbity score indicates a protein model from high quality data, while a score of 4.0 Å or higher reflects relatively poor data). In this work, the side-chain optimization algorithm improved mean MolProbity score from 2.65 Å (42nd percentile) to nearly atomic resolution at 1.41 Å (95th percentile). However, side-chain optimization with the AMOEBA many-body potential function is computationally expensive. Thus, a second contribution of this work is a parallelization scheme that utilizes nVidia graphical processing units (GPUs) to accelerate the side-chain repacking algorithm. With the use of one GPU, our side-chain optimization algorithm achieved a 25 times speed-up compared to using two Intel Xeon E5-2680v4 central processing units (CPUs). We expect the GPU acceleration scheme to lessen demand on computing resources dedicated to protein structure optimization efforts and thereby dramatically expand the number of protein structures available to aid in interpretation of missense variations associated with deafness.

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Hagströmer, Maria. "Assessment of health-enhancing physical activity at population level /." Stockholm, 2007. http://diss.kib.ki.se/2007/978-91-7357-334-4/.

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Aguilera, Castells Joan. "Acute effects of suspension training and other perturbative sources on lower limb strength tasks." Doctoral thesis, Universitat Ramon Llull, 2021. http://hdl.handle.net/10803/673431.

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Actualment, els dispositius de suspensió són un dels materials més utilitzats per produir pertorbació i enfortir de forma global la majoria de grups musculars. Encara que, manquen evidències dels seus efectes sobre l’extremitat inferior. Així, l’objectiu principal d’aquesta tesi doctoral va ser quantificar la producció de força, l’activitat muscular i la magnitud de la pertorbació a l’esquat búlgar i altres exercicis de l’extremitat inferior en condicions d’inestabilitat. Es van analitzar 18 estudis per dur a terme una revisió sistemàtica (estudi 1) i 75 participants físicament actius van ser reclutats per realitzar els diferents estudis transversals sobre els efectes dels dispositius de suspensió, les superfícies inestables i les vibracions mecàniques (plataforma vibratòria i vibració superposada) en exercicis de l’extremitat inferior (estudis 2-6). Es va confirmar que l’activació a la part inferior del cos només va ser investigada en el concentrat d’isquiosurals en suspensió (estudi 1). La posició i el ritme d’execució (70 bpm) van ser determinants per la producció de força exercida sobre el tirant de suspensió a l’esquat búlgar (estudi 2). El dispositiu de suspensió a l’esquat búlgar va augmentar les forces verticals contra el terra (estudi 3). Sobre el dispositiu la producció de força va ser major quan el nivell d’inestabilitat era baix (estudi 3 i 4), però a nivell muscular el dispositiu va ser igual de demandant que l’exercici tradicional (estudi 3). Un augment de la pertorbació, va incrementar l’activació muscular (estudis 3, 4, 5) i la magnitud de la inestabilitat per l’esquat búlgar i el mig squat amb barra (estudis 4 i 5). Així, la vibració superposada en un dispositiu de suspensió esdevé un repte per incrementar el nivell de pertorbació i millorar la força, la resistència muscular i l’estabilització (estudi 6). A més, els sensors de força són una eina adequada i usable per valorar les forces exercides sobre els dispositius de suspensió, i l’ús de l’acceleròmetre permet determinar la magnitud de la pertorbació que ofereixen els diferents materials desestabilitzadors mesurant l’acceleració del centre de masses corporal. Actualmente, los dispositivos de suspensión son uno de los materiales más utilizados para producir perturbación y fortalecer globalmente la mayoría de los músculos. Aunque, faltan evidencias de sus efectos sobre la extremidad inferior. Así, el objetivo principal de esta tesis doctoral fue cuantificar la producción de fuerza, la actividad muscular y la magnitud de la perturbación en la sentadilla búlgara y otros ejercicios de la extremidad inferior en condiciones de inestabilidad. Se analizaron 18 estudios para llevar a cabo una revisión sistemática (estudio 1) y 75 participantes físicamente activos fueron reclutados para realizar los diferentes estudios transversales sobre los efectos de los dispositivos de suspensión, las superficies inestables y las vibraciones mecánicas (plataforma vibratoria y vibración superpuesta) en ejercicios de la extremidad inferior (estudios 2-6). Se confirmó que la activación en la parte inferior del cuerpo sólo fue investigada en el concentrado de isquiosurales en suspensión (estudio 1). La posición y el ritmo de ejecución (70 bpm) fueron determinantes para la producción de fuerza ejercida sobre el tirante de suspensión en la sentadilla búlgara (estudio 2). El dispositivo de suspensión en la sentadilla búlgara aumentó las fuerzas verticales contra el suelo (estudio 3). Sobre el dispositivo la producción de fuerza fue mayor cuando el nivel de inestabilidad era bajo (estudio 3 y 4), pero a nivel muscular el dispositivo fue igual de demandante que el ejercicio tradicional (estudio 3). Un aumento de la perturbación incrementó la activación muscular (estudios 3, 4, 5) y la magnitud de la inestabilidad en la sentadilla búlgara y la media sentadilla con barra (estudios 4 y 5). Así, la vibración superpuesta en un dispositivo de suspensión se convierte en un reto para incrementar el nivel de perturbación y mejorar la fuerza, la resistencia muscular y la estabilización (estudio 6). Además, los sensores de fuerza son una herramienta adecuada y usable para valorar las fuerzas ejercidas sobre los dispositivos de suspensión, y el uso del acelerómetro permite determinar la magnitud de la perturbación que ofrecen los diferentes materiales desestabilizadores midiendo la aceleración del centro de masas corporal. Nowadays, suspension devices are one of the most widely used pieces of equipment to produce perturbation and strengthen most muscle groups globally. However, there is a lack of evidence of their effects on the lower limb. Thus, the main objective of this doctoral thesis was to quantify force production, muscle activity and the magnitude of perturbation in the Bulgarian squat and other lower extremity exercises under unstable conditions. Eighteen studies were analysed for a systematic review (study 1) and 75 physically active participants were recruited to perform the different cross-sectional studies on the effects of suspension devices, unstable surfaces, and mechanical vibrations (vibration platform and superimposed vibration) on lower limb exercises (studies 2-6). It was confirmed that lower body activation had only been previously investigated in the suspended hamstring curl (study 1). Position and pace (70 bpm) were determinants for the force exerted on the suspension strap in the Bulgarian squat (study 2). The suspension device in the Bulgarian squat increased the vertical ground reaction forces (study 3). The force production was higher on the device when the level of instability was low (study 3 and 4), but for muscle activity the device was just as demanding as a traditional exercise (study 3). Increased perturbation enhanced muscle activation (studies 3, 4, 5) and the magnitude of instability in the Bulgarian squat and barbell half-squat (studies 4 and 5). Thus, superimposed vibration on a suspension device becomes a challenge to increase the level of perturbation and improve strength, muscular endurance, and stabilisation (study 6). In addition, load cells are a suitable and practical tool to assess the forces exerted on suspension devices, and the use of an accelerometer makes it possible to determine the magnitude of the perturbation offered by different equipment providing instability by measuring the acceleration of the body's centre of mass.

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Havel, Jiří. "Zobrazení bodů na přímky a jiné parametrizace přímek nejen pro Houghovu transformaci." Doctoral thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2012. http://www.nusl.cz/ntk/nusl-261256.

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Tato práce se zabývá Houghovou transformací (HT). HT je nejčastěji používána pro detekci přímek nebo křivek, ale byla zobecněna i pro detekci libovolných tvarů. Hlavní téma této práce jsou parametrizace přímek, speciálně PTLM - zobrazení bodů na přímky. Tyto parametrizace mají tu vlastnost, že bodům v obrázku odpovídají přímky v parametrickém prostoru. Tato práce poskytuje důkazy některých vlastností PTLM. Za zmínku stojí existence páru PTLM vhodného pro detekci a efekt konvoluce v obrázku na obsah parametrického prostoru. V práci jsou prezentovány dvě implementace HT. Obě využívají k akceleraci grafický hardware. Jedna využívá GPGPU API CUDA a druhá zobrazovací API OpenGL. Jako aplikace detekce přímek je uvedena část detekce šachovnicových markerů použitelných pro rozšířenou realitu.

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Olausson, Katrin. "On Evaluation and Modelling of Human Exposure to Vibration and Shock on Planing High-Speed Craft." Licentiate thesis, KTH, Marina system, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-159168.

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High speed in waves, necessary in for instance rescue or military operations, often result in severe loading on both the craft and the crew. To maximize the performance of the high-speed craft (HSC) system that the craft and crew constitute, balance between these loads is essential. There should be no overload or underuse of crew, craft or equipment. For small high-speed craft systems, man is often the weakest link. The human exposure to vibration and shock results in injuries and other adverse health effects, which increase the risks for non-safe operations and performance degradation of the crew and craft system. To achieve a system in balance, the human acceleration exposure must be considered early in ship design. It must also be considered in duty planning and in design and selection of vibration mitigation systems. The thesis presents a simulation-based method for prediction and evaluation of the acceleration exposure of the crew on small HSC. A numerical seat model, validated with experimental full-scale data, is used to determine the crew's acceleration exposure. The input to the model is the boat acceleration expressed in the time domain (simulated or measured), the total mass of the seated human, and seat specific parameters such as mass, spring stiffness and damping coefficients and the seat's longitudinal position in the craft. The model generates seat response time series that are evaluated using available methods for evaluation of whole-body vibration (ISO 2631-1 \& ISO 2631-5) and statistical methods for calculation of extreme values. The presented simulation scheme enables evaluation of human exposure to vibration and shock at an early stage in the design process. It can also be used as a tool in duty planning, requirements specification or for design of appropriate vibration mitigation systems. Further studies is proposed within three areas: investigation of the actual operational profiles of HSC, further development of seat models and investigation of the prevailing injuries and health problems among the crew of HSC. QC 20150126

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Karis, Tomas. "Correlation between Track Irregularities and Vehicle Dynamic Response Based on Measurements and Simulations." Licentiate thesis, KTH, Farkost och flyg, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-228056.

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Deviations from the design track geometry are called track irregularities, which are a main excitation mechanism in the track–vehicle dynamic system, and very important to monitor and maintain to have trac on a line run safely and comfortably. Especially during vehicle acceptance testing, it is important that a new vehicle behaves close to design predictions and within limit values, thus it is important to be able to describe track irregularities in a consistent way. There are several methods which quantify the eects track irregularities have on a vehicle while running along the track. Most common is analyse standard deviations and percentiles and maximum values over sections with pre-defined length. However, these quantities do not correlate well with the vehicle dynamic response, e.g. two track sections with similar maxima and standard deviations can result in very dierent response of the vehicle. To improve the correlation between track irregularities and vehicle re- sponse measures, it is recommended by past research to use multiple regres- sion analysis to take e.g. vehicle speed and track curvature into account as well. Other methods range from derivatives of track irregularities, via trans- fer functions and vehicle filters to neural networks. Common for all these methods are that there is either still slight inconsistencies in the results or that they are tailored for certain vehicle types on specific lines. As a result, the preferred method to evaluate track irregularities is still to use standard deviations. In this thesis, data from three vehicles in two measurement campaigns is evaluated using a single degree of freedom model as inspiration to break down the path from track to vehicle into several steps. A weak link in these steps is identified, which shows significantly lower correlation coecients than the other steps. The weak link is the step from vertical track irregularity second spatial derivative to vertical axle box acceleration divided by the squared vehicle speed. A variable wavelength range Dx is introduced, as an alternative to the common D1 (3–25 m), D2 (25–70 m) and D3 (70–150 m) wavelength ranges. Its wavelength range corresponds to the vehicle response band-pass filter frequencies and is thus speed dependent. Simulations are also carried out to investigate the weak link and for the possibility to vary parameters that cannot be changed during on-track mea- surements. A multi-body system model of the passenger coach Bim 547.5 is used, together with recorded track data and vehicle speed from the on-track measurements. The varied parameters have rather low sensitivity and aect results to a small extent. Most impact has the randomly varying vertical track stiness which aects the vertical wheel–rail forces and axle box accelerations. In future work, it should be explored if it is possible – and in such case how – to separate the eects of varying track stiness from the track irreg- ularities. This to better understand when a vehicle response is linked more to the track irregularities or to the track flexibility. The weak link identified in the steps from track to vehicle should also be further explored, perhaps by extending the underlying model or evaluate a dierent set of measurements. Spårlägesfel är avvikelser från den nominella spårgeometrin. De är en vik- tig excitationsmekanism i det dynamiska system som bana och fordon utgör och är viktiga att övervaka och åtgärda för att trafiken ska kunna flyta sä- kert och komfortabelt. Eftersom det vid mätningar för typgodkännande av fordon är viktigt att fordonet beter sig som förväntat och inom gränsvärden, är det viktigt att kunna beskriva spårlägesfel på ett sätt som är konsekvent och motsvarar hur fordonet ”känner av” dem. Det finns ett flertal olika metoder som kvantifierar de eekter spårläges- fel har på ett fordon som rör sig längs ett spår. Vanligast är att använda standardavvikelser, percentiler och maxvärden från spårsektioner med för- definierad längd. Dessa storheter korrelerar dock inte väl med den dynamiska fordonsresponsen, till exempel kan två spårsektioner med liknande maxvärden och standardavvikelse resultera i väldigt olika fordonsrespons. För att förbättra korrelationen mellan storheter för spårlägesfel och for- donsrespons rekommenderar tidigare forskning att använda multipel regres- sionsanalys för att även ta hänsyn till till exempel fordonets hastighet eller spårets kurvatur. Det finns flera alternativa metoder, till exempel derivator av spårlägesfel, överföringsfunktioner och fordonsfilter eller neurala nätverk. Generellt ger dock dessa metoder antingen fortfarande en viss osäkerhet i resultaten, eller så är de anpassade för vissa fordonstyper på enstaka järn- vägslinjer. Sammantaget är resultatet att den metod som föredras för att utvärdera spårlägesfel, fortfarande baseras på standardavvikelser. I den här avhandlingen används en enfrihetsgradsmodell som inspiration för att bryta ner excitationsvägen från spår till fordon i ett antal steg, som sedan undersöks genom att utvärdera mätdata från tre fordon i två forsk- ningsprojekt. En svag länk bland stegen identifieras, vilken visar signifikant lägre korrelationsvärde än övriga steg. Den svaga länken är steget från spatial andraderivata av spårlägesfel till axelboxacceleration dividerat med fordons- hastigheten i kvadrat. Ett variabelt våglängdsområde Dx introduceras som ett alternativ till de vanligt förekommande D1 (3–25 m), D2 (25–70 m) och D3 (70–150 m). Det variabla våglängdsområdet motsvarar de frekvenser som används för utvärdering av fordonsrespons och är därmed hastighetsberoende. Vidare används simuleringar för att undersöka den svaga länken och för möjligheten till parametervariationer. En flerkroppsmodell (MBS-modell) av passagerarvagnen Bim 547.5 används tillsammans med uppmätta data för spår och fordonshastighet. De parametrar som varieras visar sig ha låg käns- lighet och påverkar resultaten i liten utsträckning. Störst inverkan har den slumpmässigt varierande vertikala spårstyvheten, vilken påverkar de vertikala hjul–rälkrafterna och axelboxaccelerationerna. Fortsatt forskning bör undersöka om det är möjligt att – och i så fall hur – separera eekten av varierande spårstyvhet och spårlägesfel. Detta kan ge bättre förståelse för om fordonsrespons kopplar mer till spårlägesfelen eller till spårflexibiliteten. Den svaga länken som identifierats bör också undersö- kas ytterligare, förslagsvis genom att utöka den bakomliggande modellen eller analysera annan mätdata. QC 20180517

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Weegman, Mitchell Dale. "The demography of the Greenland white-fronted goose." Thesis, University of Exeter, 2014. http://hdl.handle.net/10871/16211.

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New analytical and technological tools have the potential to yield unprecedented insights into the life histories of migratory species. I used Bayesian population models and Global Positioning System-acceleration tracking devices to understand the demographic mechanism and likely drivers underpinning the Greenland White-fronted Goose (Anser albifrons flavirostris) population decline. I used a 27-year capture-mark-recapture dataset from the main wintering site for these birds (Wexford, Ireland) to construct multistate models that estimated age- and sex-specific survival and movement probabilities and found no sex-bias in emigration or ‘remigration’ rates (chapter 2). These formed the foundation for an integrated population model, which included population size and productivity data to assess source-sink dynamics through estimation of age-, site-, and year-specific survival and movement probabilities, the results of which suggest that Wexford is a large sink and that a reduction in productivity (measured as recruitment rate) is the proximate demographic mechanism behind the population decline (chapter 3). Low productivity may be due to environmental conditions on breeding areas in west Greenland, whereby birds bred at youngest ages when conditions were favourable during adulthood and the breeding year (chapter 4), and possibly mediated by links with the social system, as birds remained with parents into adulthood, forfeiting immediate reproductive success, although a cost-benefit model showed the ‘leave’ strategy was marginally favoured over the ‘stay’ strategy at all ages (chapter 5). Foraging during spring does not appear to limit breeding, as breeding and non-breeding birds did not differ in their proportion of time feeding or energy expenditure (chapter 6). Two successful breeding birds were the only tagged individuals (of 15) to even attempt to nest, suggesting low breeding propensity has contributed to low productivity. Although birds wintering in Ireland migrated further to breeding areas than those wintering in Scotland, there were no differences in feeding between groups during spring migration (chapter 7). These findings suggest that Greenland White-fronted Geese are not limited until arrival on breeding areas and the increasingly poor environmental conditions there (chapter 8). More broadly, these findings demonstrate the application of novel tools to diagnose the cause of population decline.

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Aviat, Félix. "Development of High Performance Molecular Dynamics : Fast Evaluation of Polarization Forces The truncated conjugate gradient (TCG), a non-iterative/ﬁxed-cost strategy for computing polarization in molecular dynamics: Fast evaluation of analytical forces Truncated Conjugate Gradient: An Optimal Strategy for the Analytical Evaluation of the Many-Body Polarization Energy and Forces in Molecular Simulations". Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS498.

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La dynamique moléculaire classique est un outil précieux pour explorer le monde de l’infiniment petit, notamment lorsque l’on parle de systèmes biologiques (protéines). Ces simulations sont basées sur des modèles plus ou moins avancés, où la prise en compte des électrons n’est pas évidente. La polarisabilité permet la prise en compte de la mobilité des nuages électronique tout en conservant un cadre classique. Elle peut-être décrite par des dipôles induits, dont le calcul demande la résolution d’un schéma auto-cohérent (SCF), coûteux en terme de temps de calcul et source d’instabilité. Dans cette thèse, nous proposons un nouvel algorithme permettant un traitement plus rapide et plus stable des dipôles induits, basé sur la troncature du Gradient Conjugué. La précision, la versatilité, l’efficacité du Gradient Conjugué Tronqué (TCG) sont évalués sur plusieurs système. Son application à des calculs plus sensibles d’énergie libre est également testée. Le TCG est enfin utilisé afin de mettre au point de nouveaux intégrateurs de dynamique moléculaire permettant d’importantes accélérations. On démontre finalement que TCG est un outil polyvalent, adaptable, efficace, qui permet une accélération considérable des dynamiques polarisables longues Classical molecular dynamics is a precious tools to explore the infinitely small world, e.g. when considering biological systems (such as proteins). These simulations are based on physical models of various precision and complexity, where taking electrons into account is not easy. Polarizability allows one to take into account the mobility of the electronic density, while keeping the classical description framework. It can be described using induced dipoles, whose computation is done through a Self-Consistent procedure, which is costly in terms of computational time and can also cause instability. In this thesis, we introduce a new algorithm allowing a faster and more stable treatment of the induced dipoles, based on the truncation of the Conjugate Gradient. Accuracy, versatility, efficiency of the so-called Truncated Conjugate Gradient (TCG) are evaluated on various systems. Its applicability to free energy calculations is also tested. TCG is finally used in order to derive new molecular dynamics integrators allowing for considerable accelerations. To sum this up, TCG proves to be a polyvalent, adaptable, efficient tool, which allows for substantial acceleration of long polarizable dynamics

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Chi, Wang-Yu, and 王毓娸. "Effects of Safety Belt and Falling Posture on Body Accelerations." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/y6pm9q.

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碩士 國立臺北科技大學 工業工程與管理系碩士班 101 This study investigates the effects of falling condition and safety device on a human body. Researchers employed a load cell and an tri-axial accelerometer to measure rope tension and trunk accelerations of a falling dummy with an 1.5m dropping distance. Four testing conditions combined with 2 safety devices, a full body harness and a half waist safety belt, and 2 falling conditions, fall form floor opening or backward topple, were conducted on a platform for fall experiment. Experimental results show different fall combination significantly affect safety-rope tension and dummy movement. The combination of full body harness and fall form floor opening condition results in the greatest peak rope tension and trunk acceleration. Comparatively, a half waist safety belt produces less peak rope tension but greater swing movement. The peak rope tension measured under fall form backward topple condition is significantly smaller than that measured under fall form floor opening. Nevertheless, fall form backward topple condition causes greater dummy swing and rotation and results in collisions of dummy and platform structure. Finding of this study provides related professionals with useful information of personal safety device for working at heights.

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Han, Jungmok. "Human postural control characteristics during forward stepping : relationship betwen COM and body accelerations, trunk acceleration variability and COP characteristics." 2007. http://hdl.handle.net/1993/29475.

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(9781541), Steven Bleakley. "Time frequency analysis of railway wagon body accelerations for a low-power autonomous device." Thesis, 2006. https://figshare.com/articles/thesis/Time_frequency_analysis_of_railway_wagon_body_accelerations_for_a_low-power_autonomous_device/13436474.

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This thesis examines the application of the techniques of Fourier spectrogram and wavelet analysis to a low power embedded microprocessor application in a novel railway and rollingstock monitoring system. The safe and cost effective operation of freight railways is limited by the dynamic performance of wagons running on track. A monitoring system has been proposed comprising of low cost wireless sensing devices, dubbed "Health Cards", to be installed on every wagon in the fleet. When marshalled into a train, the devices would sense accelerations and communicate via radio network to a master system in the locomotive. The integrated system would provide online information for decision support systems. Data throughput was heavily restricted by the network architecture, so significant signal analysis was required at the device level. An electronics engineering team at Central Queensland University developed a prototype Health Card, incorporating a 27MHz microcontroller and four dual axis accelerometers. A sensing arrangement and online analysis algorithms were required to detect and categorise dynamic events while operating within the constraints of the system. Time-frequency analysis reveals the time varying frequency content of signals, making it suitable to detect and characterise transient events. With efficient algorithms such as the Fast Fourier Transform, and Fast Wavelet Transform, time-frequency analysis methods can be implemented on a low power, embedded microcontroller. This thesis examines the application of time-frequency analysis techniques to wagon body acceleration signals, for the purpose of detecting poor dynamic performance of the wagon-track system. The Fourier spectrogram is implemented on the Health Card prototype and demonstrated in the laboratory. The research and algorithms provide a foundation for ongoing development as resources become available for system testing and validation.

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Song, Guang-Yu, and 宋光裕. "The influence of whole body vibration at different accelerations and knee flexion angles on EMG activation and co-contraction of the lower limbs." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/94085969354785623144.

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碩士 國立嘉義大學 體育與健康休閒研究所 97 The influence of whole body vibration at different accelerations and knee flexion angles on EMG activation and co-contraction of the lower limbs Song, Guang-Yu Graduate Institute of Physical Education, Health, and Leisure Study National Chiayi University Abstract Whole body vibration (WBV) could improve muscle strength and power immediately after intervention or in long term training. The vibration platform was used to transduce oscillations from feet up to human body and can produce approximate 0.7~4 times of gravitational acceleration (g value) (1g=9.8m/s2). To the best of knowledge, few studies have discussed the effects of different g values on human body during WBV stimulations. The squat position was commonly suggested while undergoing the WBV stimulations. However, under that squat position, the influence of WBV on the muscle activations and co-contraction of lower extremity at different knee flexion angles were unclear. The purpose of this study was to analyze the muscle activation levels and co-contraction ratios of vastus medium (VM) and bicepes femoris (BF) at different knee angles and g values during WBV stimulations. Twenty healthy college students (11 male and 9 female) were recruited in this study. Subjects were asked to take Non-Vibration (NV) and WBV at different levels (0.98g, 2.52g, 3.72g, 5.61g) with knee flexed at 45, 60, 90 degrees. EMG signals were recorded simultaneously during NV and WBV. Two-way ANOVA with repeated measures was used to compare EMG levels and co-contraction ratio at difference knee angles and g values. WBV EMG activation level of BF was significantly higher than NV when knee flexed at 60 degrees (0.98~3.72g) and 45 degrees (0.98~5.61g) during WBV stimulations. WBV EMG activation level of VM was significantly higher than NV at 0.98g and 2.5g when knee flexed 45 degrees. The VM and BF muscles activation could be significantly increased by appropriate vibration stimulation and the activation levels were mainly affected by knee flexion angles. The results of this study suggested that combination of squat position at knee flexion 45 degrees with 0.98/2.52 g WBV stimulations could have better effects on enhancing lower extremity muscle activations.

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Khaltar, Bulganchimeg, and Bulganchimeg Khaltar. "THERAPEUTIC EFFECTS OF WHOLE BODY PERIODIC ACCELERATION FOR STROKE." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/52129992365119548824.

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碩士 高雄醫學大學 醫學研究所碩士班 103 Background and Aim: Stroke is the second most common cause of mortality and the third most common cause of disability. Eighty percent of stroke survivors with post stroke impairments suffer from mobility impairment and motor coordination deficits. Whole Body Periodic Acceleration (WBPA) is the motion of the supine body in the head to foot axis (z-axis) in a sinusoidal fashion using a motion platform. The acceleration and deceleration produced by the motion of WBPA adds small pulses as a function of frequency to the native pulse rate thereby increasing pulsatile shear stress to the vascular endothelium.WBPA therapy has shown potential neuro-protective and neuro-therapeutical effects in normal and with stroke animal studies. The aim of this study was to compare outcomes following rehabilitation therapy with or without WBPA therapy in patients with post stroke mobility impairment by using assessment of balance and functional testing and level of interleukin 6 (IL-6) and high-sensitivity C-reactive protein (hs-CRP) in serum. Method:Twenty patients with chronic stroke were recruited and randomized to control or WBPA group. In the control group, patients received regular conventional rehabilitation programs. In the WBPA group, patients also received regular rehabilitation programs, and in addition, received intervention with WBPA exercise 5 times per week for 8 weeks. The intensity of WBPA was at frequency of 140 times per minute, 2 cm amplitude for 30 minutes each time. Clinical assessments were evaluated at 3 time points: before intervention (W0), after 4-week WBPA (W4), and upon completion of WBPA (W8). The outcome measures included balance test using Biodex Balance SD system, functional test using timed 10-meter walk test (TMWT) and timed-up-and-go test (TUGT), and blood test for specific inflammatory cytokines, IL-6 and hs-CRP in serum. Results:Twenty subjects (11 in WBPA group, and 9 in control group) were enrolled in study. The average age of the study population was 57.1 years old and 65% were male gender. Half of the included population had ischemic stroke, and the average time post stroke onset was 30.95 months. When evaluating proportional changes in balance and functional mobility between follow-up testing periods, results in rightward limits of stability testing indicated significant improvement in WBPA group (P=0.003). There were also improvement in FRI in both WBPA and control groups, indicating statistically significant differences (P=0.010, P=0.031) between follow-up periods. Conclusion:Our study demonstrated that WBPA therapy combined with conventional physical therapy enhanced the effects of conventional physical therapy on balance in patients with chronic stroke by indicating a tendency toward improved balance and control. WBPA treatment combined with conventional physical therapy did not increase inflammatory cytokines level comparing to physical therapy alone, indicating safety treatment to use in subjects with disability following stroke as well as other conventional physical treatments. WBPA therapy may be applied in patients with chronic stroke for improved balance and functional mobility.

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Chuang, Tien-Hao, and 莊典豪. "Design of body acceleration recording and wireless transmission system." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/66708387806959883215.

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碩士 長庚大學 電機工程研究所 93 Physiological information such as electrocardiogram (ECG), body accelerations, etc. provides important vital sign or pathological information for physiological monitoring and assessment. The long-term ECG recording can catch spontaneous cardiac arrhythmia and investigate the autonomic-related heart rate variability (HRV). The characteristics of HRV and the related autonomic mediation in different physical activities can be investigated by parallel recording the body accelerations. In this thesis, a low-power microcontroller-based (MSP430F149, Texas Instruments, USA) recording system was developed to parallel record ECG and accelerations measured on the chest and the thigh. To avoid the inconvenience caused by wire connection, the accelerations on the thigh is wireless transmitted into the recording system. The system can be operated more than 24 hours. The data stored in the system were retrieved for physical activity classification (lying, sitting, standing and dynamic activity) and HRV analysis to assess the alteration of the autonomic nervous system in different activities.

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Chang, Chien Hsu-Fang, and 張簡旭芳. "Relationships between Body Acceleration and Velocity during Different Gait Pattern." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/58617477424997359847.

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碩士 國立臺灣師範大學 運動競技學系 104 Introduction：The population engaged in exercise increases annually. One of the main reasons for exercising is for promoting overall health; therefore, the accuracy of measuring physical activity is critical. In recent years, the electronic industry has been booming and wearable technology is getting increasingly mature. The accelerometer has made a big breakthrough in accuracy, volume and convenience and is now a necessity for recording physical activity. Although accelerometers are commonly used in measuring physical activity, the algorithms are quite diverse and not yet standardized. The moving speed is an index of exercise intensity but the correlations between the physical acceleration and moving speed are not yet clear. Purpose: The purpose of this study is to examine: 1) the correlations between the physical acceleration, moving speed and heart rate reserve (HRR%)； 2） a better algorithm for estimating physical acceleration at different walking and running speeds. Method: This study recruited 19 healthy males who were asked to wear a heart rate monitor and a tri-axis accelerometer to perform walking and running at different speeds. Each speed was tested for 3 minutes followed by a rest until the participants returned to their standing rest heart rate. A one-minute stable heart rate of each trial was gathered for data analysis. After being processed with different algorithms the acceleration values were analyzed with moving speeds and HRR% respectively. The Pearson product-moment correlation coefficient was used to examine the relationships between walking, running, the entire walking-running period, physical acceleration, moving speeds and HRR%. Result: In the walking, running, and the entire walking-running period, the peak values of resultant acceleration and the MAD values of anterior-posterior acceleration showed significant correlations with moving speeds (r=.829**、.514**、.836**； r=.833**、.637**、.780**) and HRR% (r=.771**、.517**、.856**； r= .837**、.651**、.787**). Conclusion: It is feasible to estimate the exercise intensity for walking, running and the entire walking-running period with the peak values of resultant acceleration and the MAD values of anterior-posterior acceleration. The results can be used as a foundation for the future application in measuring physical activity.

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Hsieh, Ming Hung, and 謝明宏. "A portable ECG and body acceleration measurement device and exercise intensity-related ECG analysis." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/93454238530731369644.

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Cheng, Chun-Shih, and 鄭淳詩. "Accuracy tri-axis acceleration signal at different body positions for the step counter algorithm research." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/mu8j59.

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碩士 國立中興大學 應用數學系所 101 The pedometer is a useful tool for measuring physical activity. It is a simple and convenient reference instrument. Physical activity can effectively improved through wearing the pedometer. The pendulum pedometer can only provide more accurate step counter without estimating energy expenditure and distance of step. With Micro Electrical Mechanical Systems (MEMS) technology developed, recently, the price and volume become cheap and small. The accelerometer has advantage include portability, lightweight and low cost. It is usually provide a count value, intensity and duration of physical activity. The accuracy of step counter can influenced by wearing the accelerometer at different body position. The purpose of thesis is obtain adequate the step counter algorithm through signal process and step detection. Seventeen healthy male (age:23.8 ± 1.75 years, body mass index (BMI): 22.14 ± 3.17 kg/m2; mean ± SD)volunteered to participate in this study. The accelerometer which is adopt sampling frequency 200 Hz and sensitivity 667 count/g is collected acceleration signal. All the participators are told to wear the accelerometers at five specific positions of body include chest, pocket of chest, arm, pocket of pants and waist, simultaneously, collect the acceleration data. They are told to walk 40 steps in the velocity about 80 steps per minutes on cement walkway. The step counter estimated steps by Zero-cross detection method and Peak detection method, and their corresponding errors are about 0.46 ± 0.14% and 35.08 ± 13.81%. Then we analysed the errors by t-test, and found that there is no significant difference in Zero detection method (p=0.14) but significant in Peak detection method (p=0.027). In different frequency of step experiments, 60, 100, and 120 steps per minutes, except 60 step/min is below 90% degree of accuracy at arm, pocket of pants and waist, both 100 step/min and 120 step/min has 100% degree of accuracy. The results indicated that: Compared to the Peak detection method, it can overcome the effect by using Tri-axial accelerometer at different positions through the Zero-cross detection method, as a young male walk at frequency 80 step/min. And it is obviously lifted when regulating the average sliding filter rank to 40 at the slower frequency 60 step/min.

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Takacs, Judit. "The relationship between knee pain and body weight in early onset knee osteoarthritis." 2011. http://hdl.handle.net/1993/4742.

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Osteoarthritis (OA) is a group of diseases entailing degradation of joints, and has been designated as one of the key conditions for special attention during the World Health Organization’s Bone and Joint Decade (2000-2010) (Brooks & Hart, 2000). Research has demonstrated that body weight is the number one modifiable risk factor associated with the onset and progression of knee OA (Felson, 1996). However, exercise programs that aim to initiate weight loss and improve pain and function in knee OA often increase loading on the knee joint, contributing to degeneration of the knee and progression of the disease (Miyazaki et al, 2002). The introduction of a new anti-gravity treadmill, which utilizes a technology called Lower Body Positive Pressure (LBPP), allows the examination of the relationship between weight, knee pain and knee loading via knee acceleration during exercise. The null hypothesis states that there will be no significant difference in knee pain, knee function and knee joint acceleration when comparing full weight bearing and LBPP treadmill walking exercise in a young knee OA population. Twenty-two overweight/obese patients with mild or moderate early-onset knee OA were recruited to complete two 25 minute treadmill walking sessions (one full weight-bearing and one LBPP walking session) one week apart and two walkway walking sessions. Knee pain and knee acceleration were recorded. Paired t-tests and ANOVAs were used to compare conditions. On average, an LBPP of 12.3% body weight reduction reduced knee pain in our population. Knee pain was significantly lower during LBPP walking than during full weight-bearing walking. Knee acceleration decreased with increasing LBPP. Heel strike and toe-off data from walkway walking trials illustrated significantly different knee acceleration about the knee (slow walking loads were lower / fast walking were higher), as compared to treadmill walking sessions. This study illustrates that treadmill walking at a minimal level of LBPP can decrease knee pain and attenuate knee joint loads while allowing patients to complete exercise programs aimed at initiating weight loss and improving pain and function in knee OA. LBPP appears to be a promising tool for rehabilitation for those with painful knee OA and other lower body musculoskeletal conditions.

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Brand, Matthew C. "The effect of two compensatory acceleration training methods on upper-body strength in NCAA Division III collegiate level athletes." 2004. http://www.oregonpdf.org.

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Jack, Robert Joel. "INVESTIGATING WHOLE-BODY VIBRATION INJURIES IN FORESTRY SKIDDER OPERATORS: COMBINING OPERATOR VIBRATION EXPOSURES AND POSTURES IN THE FIELD WITH BIODYNAMIC RESPONSES IN THE LABORATORY." Thesis, 2012. http://hdl.handle.net/10214/3284.

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The purpose of this thesis was to investigate potential links between trunk stiffness, vibration transmission and whole-body vibration (WBV) injuries. The investigation was comprised of field and laboratory studies. Tri-planar trunk postures, operator injury histories and 6-degree-of-freedom (DOF) vibration exposure data were collected from eight forestry skidders during normal field operations in Northern Ontario. Using this skidder posture and vibration exposure data, the laboratory investigation examined interactions between WBV exposure levels and spectra, seated trunk postures, trunk muscle activity, and trunk stiffness on the transmission of 6-DOF vibration from the seat to several levels of the spine. The field study revealed that when driving, skidder operators were exposed to vibrations with higher accelerations and lower frequency exposures while adopting the most neutral postures. When dropping-off (DOAL), picking-up (PUAL) or ploughing a load, operators were exposed to vibrations with lower accelerations and higher frequency exposures while adopting the postures furthest away from neutral. Furthermore, operators who adopted the greatest lateral trunk bending and forward flexion for the greatest percentage of time reported low-back and neck pain, however, interestingly were not exposed to the greatest exposure accelerations. Operators who complained of neck pain as a result of twisting to see the rear of the vehicle while DOAL and PAUL experienced some of the highest translational and rotational vibration exposures during those operating conditions. This suggests that WBV exposures and postures may interact to produce operator injuries. The laboratory study revealed a number of interactions between vibration exposure (magnitude, spectra and axis), posture, muscle activity, trunk stiffness, vibration transmissibility, dominant transmission frequency and spinal level. In general, experiment conditions expected to increase trunk muscle activity and stiffness typically did. In contrast, the expected increase in vibration transmissibility and dominant transmission frequency with increased muscle activity and trunk stiffness was not present under many of the simulated field conditions. Trunk muscle activity patterns necessary to maintain required trunk postures were often out of phase with input accelerations, reducing trunk stiffness and increasing transmissibility. These results are contrary to findings from previous studies thus bringing into question the appropriateness of literature based vibration exposure guidelines.

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Delaney, Jace Angus. "Peak Running Intensities of Professional Football." Thesis, 2016. https://vuir.vu.edu.au/35988/.

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Abstract:

The use of global positioning systems (GPS) in team sports is now widespread, providing coaches with a useful tool for accurately quantifying the physical demands of training and competition. A number of training load metrics have been identified using these systems, however it was previously unclear which variables were most appropriate for use in a teamsport setting. Furthermore, traditional match analysis techniques do not accurately detect within-match fluctuations in running intensity that may provide insight into developing specific training and recovery methodologies. This series of studies first established the peak running intensities achieved during professional rugby league competition, using a novel moving average technique. This method outlined a considerable oversight in traditional methods, where the peak periods of play may have been missed. Secondly, these studies investigated the contextual factors affecting running intensity within interchange rugby league players. Next, the importance, reliability and usefulness of acceleration-based measures using GPS technology within team sports were evaluated. A comprehensive assessment of the peak running intensities achieved during team-sport competition was then performed, with particular reference to the football codes. Lastly, a novel application of power law analysis was used to quantify the relationship between running intensity and the duration of the moving average applied. This series of studies provides coaches with a precise overview of the true peak intensities of competition, and furthermore presents a simple, practical tool for estimating match running intensity as a function of time. As a result, coaches may provide players with an environment where technical, competitive and physical traits can be developed concurrently, using specific methodologies such as small-sided games. If athletes are exposed to the rigors of competition during training they will become more resilient, and when faced with these situations during a match, these events will be less “catastrophic”.

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Dissertations / Theses on the topic 'Body accelerations'

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