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Investigating the Experiences of Track Athletes during a Season-long Psychological Skills and Biofeedback Training ProgramStelfox, Kara B 07 December 2012 (has links)
The purpose of this study was to explore the experiences of five track athletes (three men and two women, aged 18-33 yrs) during a season-long PST-Biofeedback training program designed to help them learn how to self-regulate physiologically, psychologically, and emotionally. Three key psychological skills were emphasized: focus (Janelle, 2002; Nideffer & Sagal, 2006), arousal control through biofeedback training (e.g., Bar-Eli, Dreshman, Blumenstein, & Weinstein, 2002), and debriefing (Hogg, 2002; McArdle, Martin, Lennon, & Moore, 2010). The program, which consisted of one-on-one initial and final semi-structured interviews with PST-biofeedback sessions in between, was individualized to meet each athlete’s needs and progress during the study. Results indicated that the athletes found the program helpful; they perceived an improvement in their ability to focus, debrief, and control arousal in the lab; and, to varying degrees, they transferred those skills into training and competition. The athletes also perceived an improvement in their sport performances.
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A Simulation Analysis of an Emergency Department Fast Track SystemLa, Jennifer 12 1900 (has links)
The basis for this thesis involved a four month Accelerate Canada internship at the Grand River Hospital Emergency Department in Kitchener, Ontario. The Emergency Department (ED) Process Committee sought insight into strategies that could potentially reduce patient length of stay in the ED, thereby reducing wait times for emergency patients.
This thesis uses discrete event simulation to model the overall system and to analyze the effect of various operational strategies within the fast track area of the emergency department. It discusses the design and development process for the simulation model, proposes various operational strategies to reduce patient wait times, and analyzes the different scenarios for an optimal fast track strategy. The main contribution of this thesis is the use of simulation to determine an optimal fast track strategy that reduces patient length of stay, thereby reducing patient wait times.
Wait times were most significantly reduced when there was an increased physician presence/availability towards the fast track system. This had the greatest impact on the total time spent in the ED and also on queue length. The second most significant reduction to the performance measures occurred when an additional emergency nurse practitioner was supplemented to the fast track system. Accordingly, the nurse practitioner’s percent utilization increased. There was only one two-way interaction effect that was statistically significant in reducing the primary performance measure of wait times; however, the effect did not change the queue length, a secondary performance measure, by a significant amount. Finally, the implementation of a See-and-treat model variant for fast track had a negligible effect on both the average length of stay and queue length.
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Relative Damaging Ability Of Galactic Cosmic Rays Determined Using Monte Carlo Simulations Of Track StructureCox, Bradley 2011 August 1900 (has links)
The energy deposition characteristics of heavy ions vary substantially compared to those of photons. Many radiation biology studies have compared the damaging effects of different types of radiation to establish relative biological effectiveness among them. These studies are dependent on cell type, biological endpoint, radiation type, dose, and dose rate. The radiation field found in space is much more complicated than that simulated in most experiments, both from a point of dose-rate as well as the highly mixed field of radiative particles encompassing a broad spectrum of energies. To establish better estimates for radiation risks on long-term, deep space missions, the damaging ability of heavy ions requires further understanding. Track structure studies provide significant details about the spatial distribution of energy deposition events in and around the sensitive targets of a mammalian cell. The damage imparted by one heavy ion relative to another can be established by modeling the track structures of ions that make up the galactic cosmic ray (GCR) spectrum and emphasizing biologically relevant target geometries.
This research was undertaken to provide a better understanding of the damaging ability of GCR at the cellular level. By comparing ions with equal stopping power values, the differences in track structure will illuminate variations in cell particle traversals and ionization density within cell nuclei. For a cellular target, increased particle traversals, along with increased ionization density, are key identifiers for increased damaging ability.
Performing Monte Carlo simulations with the computer code, FLUKA, this research will provide cellular dosimetry data and detail the track structure of the ions. As shown in radiobiology studies, increased ionizations within a cell nucleus generally lead to increased DNA breaks and increased free radical production, resulting in increased carcinogenesis and cell death. The spatial distribution of dose surrounding ions tracks are compared for inter- and intracellular regions. A comparison can be made for many different ions based upon dose and particle fluence across those different regions to predict relative damaging ability. This information can be used to improve estimates for radiation quality and dose equivalent from the space radiation environment.
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Sensor Fusion for Automotive ApplicationsLundquist, Christian January 2011 (has links)
Mapping stationary objects and tracking moving targets are essential for many autonomous functions in vehicles. In order to compute the map and track estimates, sensor measurements from radar, laser and camera are used together with the standard proprioceptive sensors present in a car. By fusing information from different types of sensors, the accuracy and robustness of the estimates can be increased. Different types of maps are discussed and compared in the thesis. In particular, road maps make use of the fact that roads are highly structured, which allows relatively simple and powerful models to be employed. It is shown how the information of the lane markings, obtained by a front looking camera, can be fused with inertial measurement of the vehicle motion and radar measurements of vehicles ahead to compute a more accurate and robust road geometry estimate. Further, it is shown how radar measurements of stationary targets can be used to estimate the road edges, modeled as polynomials and tracked as extended targets. Recent advances in the field of multiple target tracking lead to the use of finite set statistics (FISST) in a set theoretic approach, where the targets and the measurements are treated as random finite sets (RFS). The first order moment of a RFS is called probability hypothesis density (PHD), and it is propagated in time with a PHD filter. In this thesis, the PHD filter is applied to radar data for constructing a parsimonious representation of the map of the stationary objects around the vehicle. Two original contributions, which exploit the inherent structure in the map, are proposed. A data clustering algorithm is suggested to structure the description of the prior and considerably improving the update in the PHD filter. Improvements in the merging step further simplify the map representation. When it comes to tracking moving targets, the focus of this thesis is on extended targets, i.e., targets which potentially may give rise to more than one measurement per time step. An implementation of the PHD filter, which was proposed to handle data obtained from extended targets, is presented. An approximation is proposed in order to limit the number of hypotheses. Further, a framework to track the size and shape of a target is introduced. The method is based on measurement generating points on the surface of the target, which are modeled by an RFS. Finally, an efficient and novel Bayesian method is proposed for approximating the tire radii of a vehicle based on particle filters and the marginalization concept. This is done under the assumption that a change in the tire radius is caused by a change in tire pressure, thus obtaining an indirect tire pressure monitoring system. The approaches presented in this thesis have all been evaluated on real data from both freeways and rural roads in Sweden. / SEFS -- IVSS / VR - ETT
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Radiobiological modeling using track structure analysisCoghill, Matthew Taylor 21 May 2012 (has links)
The purpose of this thesis is to present data pertinent to and propose conclusions regarding the coordination
of radiobiologic effectiveness (RBE) and linear energy transfer (LET). RBE is a quantity relating the effectiveness
of different radiations in causing cell death. LET is a measure of the rate of energy transferred to material by an
ionizing particle. This relationship of these values varies for different particles. The reason for this is still inconclusive. The petitioner has made use of a toolkit for Geant4, known as Geant4-DNA, to perform track-structure analysis on a chromosome model. Geant4 is an object-oriented program for the "simulation of the passage of particles through matter" developed by CERN that makes use of Monte Carlo methods and is expanded by Geant4-DNA to handle low-energy electron physics as well as physic-chemical effects. The chromosome model, in this case, has been developed by the petitioner as a nucleus with a basic, uniform distribution of chromatin. Radiation damage to DNA, in the form of aberrations, lesions and strand breaks, can be coordinated to energy deposited or number of ionizations occurring in the target (in this case DNA or chromatin fiber). Certain threshold values have been established as indicate of different types of DNA damage. The ultimate goal of this work is to score these clusters of events against the threshold values to determine the severity of DNA damage. The final comparison of the results for different particles will provide for a better understanding of the RBE-LET relationships by improving the understanding of the underlying nanodosimetric qualities.
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Identification and Development of a Model of Railway Track Dynamic BehaviourSteffens, David Martyn January 2005 (has links)
The research presented in this thesis has identified and developed a sophisticated computer model for the analysis of railway track dynamic behaviour to be used by the Rail Cooperative Research Centre for Railway Engineering and Technologies (Rail CRC) in Australia. To be competitive railway track owners need to extract as much performance as possible from their asset without serviceability or catastrophic failure. Railway track designers therefore need to develop more knowledge of the static and dynamic loadings that track may be subjected to in its lifetime. This would be best undertaken using computer modelling capable of quantifying the effects of train speed, traffic mix, wheel impact loading and distribution of vehicle loads into the track. A comprehensive set of criteria for the selection of a model of track dynamic behaviour was developed. An international review of state-of-the-art models which represented the railway track structure under the loading of a passing train was undertaken. The models' capabilities were assessed and a number of potential models identified. A benchmark test was initiated to compare current models available throughout the international railway research community. This unique benchmark test engaged six researchers to compare their railway track models using a set of theoretical vehicle and track data. The benchmark results showed that significantly different results may be obtained by models, depending on the assumptions of the user in representing a particular track scenario. Differing complexities and modelling methods, the number of different input parameters required and the representation of the irregularities in the wheel and rail all have effect on the results produced. As a result of these initiatives, the DARTS (Dynamic Analysis of Rail Track Structures) computer model was chosen for use by the Rail CRC. A user-friendly interface was created for DARTS by the writer, which was readily interpretable by railway design engineers. At the time of writing, DARTS was found to be suitable for detailed investigations planned by the Rail CRC for future research and was provided for use through an Intellectual Property agreement with its author.
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The effect of straightening and grinding of welds on track roughnessBona, Melissa Ellen January 2005 (has links)
Rail is a very expensive component of the railway track. Therefore, research methods extending rail life have great economic importance. During the past thirty years and, particularly during the past ten years there has been an increasing awareness throughout most rail networks in the world of the need to introduce improved design criteria, better construction techniques and higher standard track generally. This implies that quality control at all levels is mandatory if these objectives are to be achieved. With the improved understanding of degradation of track, a more complete comprehension of the costs associated with different operating and infrastructure conditions should also be developed, aiding in the determination of efficient maintenance costs and their contribution to access charges. Track and structures together account for 60% of maintenance costs, with 50% of the total being track. The UIC has done a lot of work on comparative performance indicators, and these show what potential savings much be out there for the taking, just by adopting current best practice. The old wisdom is that it's not enough o do things rights; we have to make sure that we do the right things. These developments have largely resulted from the demand for higher speeds particularly in passenger services and the demand to accept heavier axle loads of freight traffic. Whilst the conventional railway track structure is not likely to change significantly over the next ten years there will be a requirement over that period for better quality track infrastructure. This means less rail surface defects, less internal defects and less wheels irregularities. The presence of rail surface defects generally increases the roughness of the track leading to a poor passenger ride and increased safety risk with freight traffic. In addition, rail surface defects will generally increase the degradation rate of other track components; however, not all defects will produce visible track deterioration. Dynamic impacts produced by the rollingstock running over rail surface defects, such as poor welds, will, over time, create continuous rail defects, loosening of fastenings, abrasion and skewing of sleepers, crushing of ballast and loss of formation geometry. It is only in the recent years that the importance of poor welds in track has been identified. Dips and peaks must be recognised as a severe track irregularity that needs to be addressed and removed. Current maintenance activities have little effect on removing misaligned welds in track and the improvement obtained after the maintenance works is generally short lived. On the other hand, straightening operations have proven to solve the problem and maintain the results following 7 months of traffic. As part of this project, a six kilometre test section was selected on the Mt Isa Line and all welds located in this region were monitored for over 9 months to increase the understanding of the effect of individual maintenance activities on the track roughness. Three 2km Divisions were established; each Division had different maintenance activities and levels of intervention completed over the duration of the project. Over 15,000 readings were recorded and analysed. The following conclusions were drawn. The effect of cycle tamping was clearly identified when comparing the means of weld located in Division 1, 2 to the mean of welds in Division 3. Cycle tamping showed to have a significant positive effect on the dipped welds geometry and an increase in severity of peaked welds prior to their correction. Straightening operations completed in Division 1 and 2 reduced the overall mean of weld misalignments. These Divisions were subjected to different levels of straightening intervention however they produced similar results. Division 1 all dips were straightened and Division 2 only dips >0.3mm were straightened. This means that no additional benefit, in terms of overall misalignment of welds, can be gained when straightening operations target dips with a misalignment smaller than 0.3mm. Cycle grinding proved to have little effect on the removal of both dips and peaks. In fact, due to the configuration of the grinding machine, grinding operation produced a slight worsening of the dips misalignments and only a minor improvement of peaks. Although long term monitoring of the site may show minor variations in weld geometry performance, after approximately 3.9 Mgt of traffic the mean of dipped welds in Division 1 and 2 appeared to remain unaltered, as Division 3 showed a minor worsening. Furthermore, the mean of peaked welds in Division 1 and 2 appeared to remain unaltered, as Division 3 showed a minor worsening.
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Integrating railway track maintenance and train timetablesAlbrecht, Amie January 2009 (has links)
Rail track operators have traditionally used manual methods to construct train timetables. Creating a timetable can take several weeks, and so the process usually stops once the first feasible timetable has been found. It is suspected that this timetable is often far from optimal. Existing methods schedule track maintenance once the best train timetable has been determined and allow little or no adjustments to the timetable. This approach almost certainly produces suboptimal integrated solutions since the track maintenance schedule is developed with the imposition of the previously constructed train timetable. The research in this thesis considers operationally feasible methods to produce integrated train timetables and track maintenance schedules so that, when evaluated according to key performance criteria, the overall schedule is the best possible. This research was carried out as part of the Cooperative Research Centre for Railway Engineering and Technologies. We developed a method that uses a local search meta-heuristic called 'problem space search'. A fast dispatch heuristic repeatedly selects and moves a track possessor (train or maintenance task) through the network; this results in a single integrated schedule. This technique generates a collection of alternative feasible schedules by applying the dispatch heuristic to different sets of randomly perturbed data. The quality of the schedules is then evaluated. Thousands of feasible solutions can be found within minutes. We also formulated an integer programming model that selects a path for each train and maintenance task from a set of alternatives. If all possible paths are considered, then the best schedule found is guaranteed to be optimal. To reduce the size of the model, we explored a reduction technique called 'branch and price'. The method works on small example problems where paths are selected from a predetermined set, but the computation time and memory requirements mean that the method is not suitable for realistic problems. The main advantages of the problem space search method are generality and speed. We are able to model the operations of a variety of rail networks due to the representation of the problem. The generated schedules can be ranked with a user-defined objective measure. The speed at which we produce a range of feasible integrated schedules allows the method to be used in an operational setting, both to create schedules and to test different scenarios. A comparison with simulated current practice on a range of test data sets reveals improvements in total delay of up to 22%.
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Integrating railway track maintenance and train timetablesAlbrecht, Amie January 2009 (has links)
Rail track operators have traditionally used manual methods to construct train timetables. Creating a timetable can take several weeks, and so the process usually stops once the first feasible timetable has been found. It is suspected that this timetable is often far from optimal. Existing methods schedule track maintenance once the best train timetable has been determined and allow little or no adjustments to the timetable. This approach almost certainly produces suboptimal integrated solutions since the track maintenance schedule is developed with the imposition of the previously constructed train timetable. The research in this thesis considers operationally feasible methods to produce integrated train timetables and track maintenance schedules so that, when evaluated according to key performance criteria, the overall schedule is the best possible. This research was carried out as part of the Cooperative Research Centre for Railway Engineering and Technologies. We developed a method that uses a local search meta-heuristic called 'problem space search'. A fast dispatch heuristic repeatedly selects and moves a track possessor (train or maintenance task) through the network; this results in a single integrated schedule. This technique generates a collection of alternative feasible schedules by applying the dispatch heuristic to different sets of randomly perturbed data. The quality of the schedules is then evaluated. Thousands of feasible solutions can be found within minutes. We also formulated an integer programming model that selects a path for each train and maintenance task from a set of alternatives. If all possible paths are considered, then the best schedule found is guaranteed to be optimal. To reduce the size of the model, we explored a reduction technique called 'branch and price'. The method works on small example problems where paths are selected from a predetermined set, but the computation time and memory requirements mean that the method is not suitable for realistic problems. The main advantages of the problem space search method are generality and speed. We are able to model the operations of a variety of rail networks due to the representation of the problem. The generated schedules can be ranked with a user-defined objective measure. The speed at which we produce a range of feasible integrated schedules allows the method to be used in an operational setting, both to create schedules and to test different scenarios. A comparison with simulated current practice on a range of test data sets reveals improvements in total delay of up to 22%.
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Assessment of risk factors for stress fractures and future osteoporosis in female collegiate cross country runnersVerdegan, Laura. January 2007 (has links) (PDF)
Thesis PlanB (M.S.)--University of Wisconsin--Stout, 2007. / Includes bibliographical references.
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