Dissertations / Theses on the topic 'Skull modeling'
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1
Patel, Jayesh V. "Computer aided modeling and analysis of the human skull for varied impact loads." Ohio : Ohio University, 1993. http://www.ohiolink.edu/etd/view.cgi?ohiou1175719398.
2
Andersson, Frida. "Finite Element Modeling of Skull Fractures : Material model improvements of the skull bone in theKTH FE head model." Thesis, KTH, Skolan för teknik och hälsa (STH), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-192629.
Abstract:
The main aim of this project was to develop a model for predicting skull fractures of a 50th percentile male, using a finite element head model developed at the Neuronics department of KTH, Royal Instituteof Technology. The skull bone is modeled as a three layered bone, where the outer and inner tables are modeled as shell elements, while the diploë is modeled by two layers of solid elements. The material model of the tables was changed from the material model MAT_PLASTIC_KINEMATIC to a material model including a damage parameter to soften the damaged material and to enable ploting of the damage of the skull bone. Due to the coarse mesh of the FE head model the material model was not allowed to include any erosion, deleting element as they reach their ultimate strain. With these requests, two materials from the LS-DYNA material library seemed appropriate: material 81,MAT_PLASTICITY_WITH_DAMAGE and material 105, MAT_DAMAGE_2. To evaluate these materials and adjust the input parameters a dog bone FE model was developed and tension tests were simulated with this model, equivalent to tension tests performed on equally shaped skull bone specimens. The material simulating a behavior most similar to the behavior from the tension tests turned out to be material 81. This material model was then implemented in the full FE head model for further input parameter adjustment and validation. Four different cadaver experiments were simulated, with different impacting objects: sphere, box, cylinder and flat cylinder surface, and impacted areas of the head: vertex, temporo-parietal and frontal. The forces obtained in the simulations were compared to the forces of the cadaver experiments. The fracture prediction was based on the damage parameter, which could be plotted to visualize the areas where the ultimate strain was exceeded and thereby the area most likely to be fractured. This parameter was then compared to the documented fractures from the cadaver experiments. The result showed that using material 81 with the input parameter EPPFR=0.05 gave the overall most accurate forces and fracture predictions. The breaking stress, σB, did not affect the fractures significantly but a reduced σB resulted in reduction of the peak forces. The thickness of the diploë did not have any significant impact on the fracture occurrence, but a thinner diploë had a reducing impact on the peak forces as well.
3
Huang, Xu. "Modeling of scaffold for cleft-repairing through finite element analysis." University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1530273324567169.
4
Siegel, Alice. "Etude de l’interaction mécanique entre un dispositif médical implantable actif crânien et le crâne face à des sollicitations dynamiques." Thesis, Paris, ENSAM, 2019. http://www.theses.fr/2019ENAM0012.
Abstract:
Dans le cadre du développement accru d’implants crâniens actifs, l’étude de la résistance du complexe crâne-implant face à des chocs modérés est nécessaire afin d’assurer la sécurité du patient. Le but de cette thèse est de quantifier l’interaction mécanique entre le crâne et l’implant afin de développer un modèle éléments finis prédictif utilisable pour la conception des futurs dispositifs. Dans un premier temps, des essais matériaux sur titane et silicone ont permis d’extraire les paramètres élastiques, plastiques et de viscosité de leurs lois de comportement. Ces paramètres ont ensuite été implémentés dans un modèle éléments finis de l’implant sous sollicitations dynamiques, validé par des essais de choc de 2,5 J. L’implant dissipe une partie de l’énergie du choc et le modèle obtenu permet d’optimiser la conception de l’implant afin qu’il reste fonctionnel et étanche après l’impact. La troisième partie porte sur l’élaboration d’un modèle éléments finis du complexe crâne-implant sous sollicitations dynamiques. Des essais sur têtes cadavériques ovines ont permis d’optimiser les paramètres d’endommagement du crâne. Le modèle complet du complexe crâne-implant, corrélé à des essais de choc, apporte des éléments de réponses sur le comportement du crâne implanté face un choc mécanique, permettant ainsi d’optimiser la conception de l’implant afin de garantir l’intégrité du crâne.Ce modèle représente un premier outil pour l’analyse de l’interaction mécanique entre crâne et implant actif, et permet de dimensionner ce dernier de sorte à garantir son fonctionnement et son étanchéité, tout en assurant l’intégrité du crâneActive cranial implants are more and more developed to cure neurological diseases. In this context it is necessary to evaluate the mechanical resistance of the skull-implant complex under impact conditions as to ensure the patient’s security. The aim of this study is to quantify the mechanical interactions between the skull and the implant as to develop a finite element model for predictive purpose and for use in cranial implant design methodologies for future implants. First, material tests were necessary to identify the material law parameters of titanium and silicone. They were then used in a finite element model of the implant under dynamic loading, validated against 2.5 J-impact tests. The implant dissipates part of the impact energy and the model enables to optimize the design of implants for it to keep functional and hermetic after the impact. In the third part, a finite element model of the skull-implant complex is developed under dynamic loading. Impact tests on ovine cadaver heads are performed for model validation by enhancing the damage parameters of the three-layered skull and give insight into the behavior of the implanted skull under impact.This model is a primary tool for analyzing the mechanical interaction between the skull and an active implant and enables for an optimized design for functional and hermetic implants, while keeping the skull safe
5
Ghazzawi, Zaid. "Modelling of the craniofacial skeleton : an investigation of skull biomechanics." Thesis, University of Surrey, 2002. http://epubs.surrey.ac.uk/815/.
6
Shearer, Samuel R. "Modeling second language change using skill retention theory." Monterey, California: Naval Postgraduate School, 2013. http://hdl.handle.net/10945/34742.
Abstract:
Approved for public release; distribution is unlimitedLoss of foreign language proficiency is a major concern for the Department of Defense (DoD). Despite significant expenditures to develop and sustain foreign language skills in the armed forces, the DoD has not been able to create a sufficient pool of qualified linguists. Many theories and hypotheses about the learning of foreign languages are not based on cognitive processes and lack the ability to explain how and why foreign language proficiency changes. This work analyzed 13 years of Defense Language Institute (DLI data) from over 16,000 military linguists to determine if cognitive-based skill retention theory can adequately explain foreign language change. Relationships between independent variables suggested by skill retention theory and second language change were investigated. Language proficiency and the length of time since DLI graduation demonstrated strong correlations with foreign language change. This research also affirms that decayed foreign language proficiency may be rapidly reacquired upon sufficient re-exposure to the target language. Additionally, this research proposes foreign language proficiency levels that must be attained to reduce language decay. The research findings are important since they may be used to determine a linguists language decay over time and will help schedule appropriate refresher training to reduce decay or maintain current foreign language proficiency.
7
Downey, Margaret J. "Effects of observer's experience and skill level on learning and performance in motor skill modeling." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=70288.
Abstract:
Expertise effects on response acquisition (learning) and performance reproduction (performance) (Bandura, 1986) in dance observational learning were investigated. Over an acquisition period, forty university students with varied movement backgrounds observed dance demonstrations, arranged still photos to represent the dances, and performed each dance. Learning was assessed via a pictorial-resequencing task. Dance performance accuracy and quality were evaluated via detailed analyses of videotaped performances. Results indicated that dance experts learn more and perform better than novices (p $<$.05) in a modeling situation, and learning and performance scores are positively correlated at a moderate level. Entry-level dance skill is the best present indicator of success in dance observational learning. Elementary instruction can improve beginner dancers' observational learning ability. The findings support Bandura's social cognitive theory of modeling (1986), extend the knowledge base related to the effects of expertise in motor skill acquisition, and have implications for dance and other motor skill educators.
8
Rafii-Tari, Hedyeh. "Modeling and skill assessment for robot-assisted endovascular catheterization." Thesis, Imperial College London, 2015. http://hdl.handle.net/10044/1/38451.
Abstract:
Endovascular techniques have been embraced as a minimally-invasive treatment approach within different disciplines of interventional radiology and cardiology. The current practice of endovascular procedures, however, is limited by a number of factors including exposure to high doses of X-ray radiation, limited 3D imaging, and lack of contact force sensing and haptic feedback from the endovascular tools and the vascular anatomy. More recently, development of robotic platforms have aimed to improve these practices by removing the operator from the radiation source and increasing the precision and stability of catheter motion with added degrees-of-freedom. Despite their increased application and a growing research interest in this area, many such systems have been designed without considering the natural manipulation skills and ergonomic preferences of the operators. Existing studies on tool interactions and behaviour patterns of operators have been very limited, and presently there is a lack of objective and quantitative metrics for performance and skill evaluation. This research proposes a framework for automated and objective assessment of endovascular skill, by measuring catheter-tissue contact forces and operator force/motion patterns across different skill levels, relating operator tool forces to catheter dynamics and forces exerted on the vasculature, and learning the underlying force and motion patterns that are characteristic of skill. Furthermore, a novel cooperative robotic catheterization system based on 'Learning-from-Demonstration' is developed, by utilizing a learning-based approach for generating optimum motion trajectories from multiple demonstrations of a catheterization task, as well as encoding the higher-level structure of a task as a sequence of primitive motions, to enable semi-autonomous catheter navigation within a collaborative setting. The results provide important insights into improving catheter navigation in the form of assistive or semi-autonomous robotics, and motivate the design of collaborative robots that are intuitive to use, while reducing the cognitive workload of the operator.
9
Zhao, Yuchen. "Human skill capturing and modelling using wearable devices." Thesis, Loughborough University, 2017. https://dspace.lboro.ac.uk/2134/27613.
Abstract:
Industrial robots are delivering more and more manipulation services in manufacturing. However, when the task is complex, it is difficult to programme a robot to fulfil all the requirements because even a relatively simple task such as a peg-in-hole insertion contains many uncertainties, e.g. clearance, initial grasping position and insertion path. Humans, on the other hand, can deal with these variations using their vision and haptic feedback. Although humans can adapt to uncertainties easily, most of the time, the skilled based performances that relate to their tacit knowledge cannot be easily articulated. Even though the automation solution may not fully imitate human motion since some of them are not necessary, it would be useful if the skill based performance from a human could be firstly interpreted and modelled, which will then allow it to be transferred to the robot. This thesis aims to reduce robot programming efforts significantly by developing a methodology to capture, model and transfer the manual manufacturing skills from a human demonstrator to the robot. Recently, Learning from Demonstration (LfD) is gaining interest as a framework to transfer skills from human teacher to robot using probability encoding approaches to model observations and state transition uncertainties. In close or actual contact manipulation tasks, it is difficult to reliabley record the state-action examples without interfering with the human senses and activities. Therefore, wearable sensors are investigated as a promising device to record the state-action examples without restricting the human experts during the skilled execution of their tasks. Firstly to track human motions accurately and reliably in a defined 3-dimensional workspace, a hybrid system of Vicon and IMUs is proposed to compensate for the known limitations of the individual system. The data fusion method was able to overcome occlusion and frame flipping problems in the two camera Vicon setup and the drifting problem associated with the IMUs. The results indicated that occlusion and frame flipping problems associated with Vicon can be mitigated by using the IMU measurements. Furthermore, the proposed method improves the Mean Square Error (MSE) tracking accuracy range from 0.8˚ to 6.4˚ compared with the IMU only method. Secondly, to record haptic feedback from a teacher without physically obstructing their interactions with the workpiece, wearable surface electromyography (sEMG) armbands were used as an indirect method to indicate contact feedback during manual manipulations. A muscle-force model using a Time Delayed Neural Network (TDNN) was built to map the sEMG signals to the known contact force. The results indicated that the model was capable of estimating the force from the sEMG armbands in the applications of interest, namely in peg-in-hole and beater winding tasks, with MSE of 2.75N and 0.18N respectively. Finally, given the force estimation and the motion trajectories, a Hidden Markov Model (HMM) based approach was utilised as a state recognition method to encode and generalise the spatial and temporal information of the skilled executions. This method would allow a more representative control policy to be derived. A modified Gaussian Mixture Regression (GMR) method was then applied to enable motions reproduction by using the learned state-action policy. To simplify the validation procedure, instead of using the robot, additional demonstrations from the teacher were used to verify the reproduction performance of the policy, by assuming human teacher and robot learner are physical identical systems. The results confirmed the generalisation capability of the HMM model across a number of demonstrations from different subjects; and the reproduced motions from GMR were acceptable in these additional tests. The proposed methodology provides a framework for producing a state-action model from skilled demonstrations that can be translated into robot kinematics and joint states for the robot to execute. The implication to industry is reduced efforts and time in programming the robots for applications where human skilled performances are required to cope robustly with various uncertainties during tasks execution.
10
Meador, Douglas P. "Modeling Training Effects on Task Performance Using a Human Performance Taxonomy." Wright State University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=wright1229535534.
11
Kaffer, Christine L. "The Effects of Video Modeling on Skill Acquisition in Children with Autism Spectrum Disorder." Diss., The University of Arizona, 2010. http://hdl.handle.net/10150/193605.
Abstract:
The current study examined the effectiveness of a video modeling procedure on a basicmath skill acquisition in students with Autism Spectrum Disorder (ASD) using a multipleprobe across students design. Participants were four kindergarten/first grade students in aself-contained classroom in an urban public school. All met the criteria for ASD prior tobeginning the study. The independent variable included a video model teaching a basicmath skill. The dependent variable was correct student response. Results indicated thatone of the four students responded to the intervention immediately and these skillsmaintained over time. However, the other three students did not respond to videomodeling instruction. Conclusions regarding the effectiveness of the video modelingprocedure for teaching math skills were inconclusive. Implications for further researchare addressed.
12
St, Germain Laura. "Examining the Optimal Frequency of Modeling Under Varied Constrained Choice Conditions for the Learning of a Dance Skill." Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/37918.
Abstract:
Various constrained frequencies of skilled model observation, under self-controlled conditions, were examined to determine whether there was an optimal frequency of modeling for learning a dance movement. Forty-eight participants with no previous dance/gymnastics experience first did a pre-test, then learned the skill over 60 interspersed observational and physical practice trials in one of four conditions that consisted of either (1) 25%, (2) 50%, (3) 75% modeling frequencies, or (4) no constraint imposed. This 60-trials acquisition phase was followed by a 24-hour post-test. Physical performance, scored by two external evaluators, revealed a significant main effect of Time from pre- to post-test (F(1, 44) = 120.43, p < .001). Cognitive representation scores revealed a main effect of Time for an image selection test (F(1, 44) = 39.09, p < .001), and a Time by Decision interaction for a forced-choice test (F(1.53, 67.48) = 7.00, p = .004). While learning was demonstrated for all measures, evidenced by higher scores at post-test than at pre-test, no main effect of Group was obtained. Consequently, the frequencies of modeling tested here under self-controlled learning conditions were equally beneficial for the learning of the novel dance skill.
13
Weng, Ng Giap. "Modelling skill learning for augmented and virtual reality learning environments." Thesis, University of Salford, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.502807.
14
Stancliff, Stephen B. "Learning to fly developing an autonomous aerial vehicle using human skill modeling /." [Florida] : State University System of Florida, 2000. http://etd.fcla.edu/etd/uf/2000/amt2442/Thesis.pdf.
Abstract:
Thesis (M.E.)--University of Florida, 2000.Title from first page of PDF file. Document formatted into pages; contains vi, 101 p.; also contains graphics. Vita. Includes bibliographical references (p. 100).
15
Smith, Joshua L. "Effects of Video Modeling on Skill Acquisition in Learning the Golf Swing." Diss., CLICK HERE for online access, 2004. http://contentdm.lib.byu.edu/ETD/image/etd632.pdf.
16
Mulqueen, Danah. "Using Video Modeling and Video Feedback to Improve Olympic Weightlifting Technique." Scholar Commons, 2014. https://scholarcommons.usf.edu/etd/5280.
Abstract:
Behavioral coaching procedures have been evaluated and enhanced over the years to find the most effective interventions for athletic performance in a variety of sports settings. Different types of feedback have been evaluated for effectiveness in teaching and improving skills. The purpose of this study was to examine the effects of video modeling and video feedback to improve technique for three novice individuals in a fitness program incorporating Olympic weightlifting. Two weightlifting events, the clean and jerk and snatch, were targeted for intervention. Each lift was broken down into a task analysis, and trainers used the task analysis to score each lift. Video modeling and video feedback was effective in improving all three participant's lifts from baseline. Annie's lifts improved from 37% in baseline to 79% in intervention for the clean and jerk, and 24% to 75% for the snatch. Rich's lifts improved from 79% in baseline to 95% following intervention for clean and jerk, and 58% to 89% for the snatch. Fran improved from 60% to 87% on the clean and jerk, and from 51% to 84% on the snatch.
17
Moazen, Mehran. "Investigating the biomechanics of a lizard skull using advanced computer modelling techniques with experimental validation." Thesis, University of Hull, 2008. http://hydra.hull.ac.uk/resources/hull:1686.
Abstract:
Lizard skulls vary greatly in shape and construction, and radical changes in skull form during evolution have made this an intriguing subject of research. The mechanics of feeding have surely been affected by this change in skull form, but whether this change in feeding is the driving force behind the change in skull shape is the underlying question being addressed throughout this project. Here the skull of 'Uromastyx hardwickii', an akinetic herbivorous lizard has been analysed using advanced computer modelling techniques. This study aimed to perform a multibody dynamics analysis (MDA) on a biting lizard skull so that bite forces, joint forces, ligament forces and muscle forces could be accurately predicted. Then, using this MDA load data stresses and strains within the skull were assessed using finite element analysis (FEA). These FE analyses were used to assess biting performance and to test hypotheses that consider biomechanical optimization of bone as the main reason behind the modification of skull shape during its evolution. Sutures were modelled and their effect on skull strains was assessed through a series of investigative studies. Finally, representative basal skull forms were examined to highlight potential implications of specific skull variations. To assist in validation of the computational modelling experimental strain gauging was conducted. The MDA provided detailed information on cranial biomechanics and associated cranial forces in this animal. It is believed that this technique will play a pivotal role in the analysis of skulls in the future and this study has demonstrated its definite potential. Cranial kinesis was seen to be mechanically significant in reducing joint reaction forces acting upon the skull, and specific groups of sutures (i.e. the frontal-parietal suture) in the Uromastyx skull played a substantial role in relieving strain compared to the other sutures, raising the questions about the original role of mesokinesis in squamate evolution.
18
Eslaminejad, Ashkan. "Dynamical Modelling of an Idealized Hemispherical Skull Model with Fluid Pressure Interactions Using Modal Analysis." Diss., North Dakota State University, 2019. https://hdl.handle.net/10365/29776.
Abstract:
In this dissertation, a non-invasive intracranial pressure (ICP) monitoring technique is introduced by developing a head dynamic model. The technique is based on modal frequency testing and vibration responses analysis of the skull. To examine and verify this methodology, we conducted vibration tests on a hemispherical shell to stand as a surrogate for human cranium to measure the effect of cerebrospinal fluid (CSF) pressure on human skull dynamic response; we utilized a hammer-impact modal testing methodology on the simulated hemispherical shell to extract its dynamic response characteristics. To be able to examine the CSF-skull dynamics interactions, we measured the skull impulse responses using mechanical tensile tests at different strain rates. The modal analysis by finite elements eigenvalue analysis of the upper cranium skull model was conducted to find the material properties of the skull. Linear elastic, as well as, nonlinear hyperelastic material models were assumed for the skull to find its material parameters. In the simulation of the human head, the cranium was modeled as a closed clamped hemispherical aluminum shell under internal fluid pressure. The interactions of CSF with the simulated cranium were studied and the frequency responses were obtained at different interior pressures. A numerical procedure for dynamic analysis of the systems was developed to measure the modal frequencies of the setup. We examined the changes to the peaks of frequency response under different fluid pressure. The results of modal analyses demonstrate changes in the frequency of bending-wave vibration modes, while longitudinal-wave modes are nominally altered under variable pressure conditions. A single-degree of freedom vibrational model was also developed to fit to the data for the sensitive modes. Linear regression analysis of the results reveals that the dynamic model?s equivalent damping and stiffness parameters are sensitive to fluid pressure variations while the equivalent mass parameter is relatively unaffected. As a result of this study we conclude that variance in CSF pressure has a measurable effect on the dynamic characteristics of the cranium and vice-versa. A calibrating system to connect the dynamic changes of the head can stand as a non-invasive system for ICP changes.
19
Angla, Célestine. "Fast transcranial acoustic simulations for personalized dosimetry in ultrasound brain therapy." Electronic Thesis or Diss., université Paris-Saclay, 2023. http://www.theses.fr/2023UPAST207.
Abstract:
La thérapie par ultrasons de pathologies cérébrales est très prometteuse, notamment pour son caractère non invasif lorsque la sonde ultrasonore reste externe au crâne. Cependant, la structure complexe de l'os du crâne atténue et perturbe fortement la propagation du faisceau ultrasonore, ce qui altère les dimensions, la position et l'intensité de la tâche focale. Or ces paramètres focaux doivent être parfaitement maitrisés pour assurer à la fois l'efficacité et la sureté du traitement. En raison de la grande variabilité inter et intra individus de la géométrie et des propriétés acoustiques du crâne, des simulations personnalisées sont nécessaires pour prédire les caractéristiques focales en fonction du patient et de la position de la sonde ultrasonore. La plupart des méthodes de simulations utilisées actuellement, telles que k-Wave, sont très gourmandes en temps de calcul et en espace mémoire, ce qui les limite à des outils de planning pré-intervention. L'objectif de cette thèse était de développer une méthode semi-analytique rapide et réaliste de calcul de champ ultrasonore au travers du crâne. Dans un premier temps, un modèle lisse et homogène du crâne, réaliste et favorable aux algorithmes de calcul de champ rapides, a été développé. Pour cela, les surfaces internes et externes du crâne ont été modélisées en utilisant une méthode appelée « Multi-level Bspline Approximation », et une méthode d'homogénéisation des propriétés acoustiques du crâne a été développée et validée numériquement. Ce modèle de crâne lisse et homogène a ensuite été utilisé en entrée de l'algorithme de calcul de champ développé. Cet algorithme, nommé SplineBeam, est basé sur une méthode de calcul des trajets ultrasonores par minimisation de la fonction temps de vol, qui est rapide et précise, et qui, combinée à la méthode des pinceaux, permet un échantillonnage régulier de la sonde ultrasonore. SplineBeam a été validé numériquement, par comparaison avec le modèle pinceau, implémenté dans la plateforme de simulation CIVA HealthCare, développée au CEA, et avec d'autres solvers numériques (dont k-Wave) sur une série de configurations, et expérimentalement, par comparaisons avec des champs de pressions acquis par hydrophone au travers d'un échantillon de crâne ex vivo. Les champs simulés avec SplineBeam se sont avérés être plus proches des champs mesurés expérimentalement que les champs simulés avec k-Wave, ce qui valide à la fois le modèle du crâne et la méthode de calcul de champ. De plus, SplineBeam peut restreindre son calcul à la tâche focale, ce qui, pour une grande sonde, lui permet de réduire drastiquement le nombre de points de calcul et d'avoir des temps de calcul de deux ordres inférieurs à ceux de k-WaveUltrasound brain therapy is a promising method, as it is non-invasive when ultrasonic waves are sent through the skull. However, the skull bone complex structure strongly attenuates and aberrates the ultrasound beam, altering the dimensions, position and intensity of the focal spot. These focal parameters must be perfectly controlled to ensure both treatment efficacy and safety. Due to the high inter/intra-individual variability of skull geometry and acoustic properties, personalized simulations are required to predict focal characteristics depending on the patient skull and the ultrasonic probe position. Most simulation methods currently in use, such as k-Wave, are very time- and memory-intensive, limiting them to pre-intervention planning tools. The aim of this thesis was to develop a fast and realistic semi-analytical method for ultrasound field computation through the skull. As a first step, we developed a smooth and homogeneous model of the skull, realistic and suited to fast field computation algorithms. To this end, we modeled the skull inner and outer surfaces using a method called "Multi-level Bspline Approximation", and we developed a skull acoustic property homogenization method, which was numerically validated. This smooth and homogeneous skull model was then used as input to the field computation algorithm developed. This algorithm, named SplineBeam, is based on an ultrasonic path computation method that minimizes the time-of-flight function, which is fast and accurate, and which, combined with the pencil method, enables a regular sampling of the ultrasound probe. SplineBeam was validated numerically, by comparison with the pencil method, embedded in the CIVA HealthCare simulation platform, developed at the CEA, and with other numerical solvers (including k-Wave) on a series of configurations, and experimentally, by comparison with hydrophone measured pressure fields through an ex vivo skull sample. SplineBeam simulated fields were found to be closer to the experimentally measured ones than those simulated with k-Wave. This validates both the skull model and the field computation method. Furthermore, SplineBeam can restrict its computation to the focal spot, which allows it to drastically reduce the number of computation points, making it faster than k-Wave by two orders of magnitude, for a large probe
20
Erséus, Andreas. "Driver-Vehicle Interaction : Identification, Characterization and Modelling of Path Tracking Skill." Doctoral thesis, KTH, Fordonsdynamik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-13209.
Abstract:
Since the dawn of the automobile, driver behaviour has been an issue. Driving can result in accidents that may harm not only the driver but also passengers and the surroundings. This calls for measures that restrict the usage of vehicles and to assist the individual driver to conduct the driving in a safe, yet practically efficient manner. The vehicles should therefore be both safe and intuitive, and preferably answer to thedifferent needs of all kinds of drivers. Driving skill can be defined in many ways, depending on the objective of the driving task, but answer in some way to the question of how well the driver can conduct the driving task. To assist low skill drivers without compromising the driving demand for high skill drivers, it is of highest importance that vehicles are tested and designed to meet those needs. This includes both the testing activities in the vehicle design phase in general but also the configuration for active systems and preventive safety, preferable with settings that adapts to the skill of the individual driver. The work here comprises the definition of skill and of driver recruitment procedures, scenario design, the development of an analysis method for objective measures, and the gathering of metrics to characterize the driver skill. Moreover, a driver model has been developed that makes use of driver skill characteristics. To gather the information needed, extensive multidisciplinary literature studies were conducted, as well as using field tests and test using an advanced moving base driving simulator. Here the focus is on path tracking skill, which is the main control aspect of driving, although the developed driving scenarios allow a varying degree of path planning, which is more related to regulation. The first simulator test was done with a very simple criterion fordriver selection, but the results gave a good insight into the variation between drivers ingeneral. For the following tests the recruitment procedure was refined to find drivers with high or low vehicle control and regulation skill, a recruitment that also was verified to really represent two different populations. A method was defined that successfully identified sets of skill-related measures, with some variation in composition depending on the path tracking demand on the driver. Int he curving road scenario, for example, the highest number of skill-related measures is identified in the curves, which is reasonable since the straight segments do not require the same amount of active control from the drivers. The driver model developed uses a quasi-static analytical description of the driver knowledge of the vehicle dynamics, but possesses the capability of nonlinear descriptions. The parameters in this model are mainly physical properties that easily can be related to the driving process. Metrics gathered are used for identification of the driver model setup for a double lane change scenario using an optimization routine, with adjusted parameter settings for different velocities. With a subjective comparison of the recorded driving simulator data, the method is verified to enable driver skill settings for driver models. In addition, the method allows metrics to be gathered for driver skill identification routines, meeting the defined objectives of the project.QC20100701
21
TSUCHIDA, Nuio, Shigeru OKUMA, Tatsuya SUZUKI, Soichiro HAYAKAWA, Yoshimichi MATSUI, and Jong-Hae KIM. "Acquisition and Modeling of Driving Skills by Using Three Dimensional Driving Simulator." Institute of Electronics, Information and Communication Engineers, 2005. http://hdl.handle.net/2237/14989.
22
Buckley, David. "Skill capture in first-person shooters." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/skill-capture-in-firstperson-shooters(a5a4858b-2b48-44f1-a59b-f7e1928ea7df).html.
Abstract:
The current models of skill in video games make one of two impositions on players: either to provide an estimate of their own skill, or complete several games before they can be properly assessed. However, in order to experience the most enjoyment and greatest sense of immersion, players need to play against the right difficulty. In order to assign the appropriate difficulty, the player's skill must first be captured accurately and quickly, before the player gets frustrated or bored. Rather than relying on game results that need to be averaged over several games, this thesis proposes predicting a player's skill from their behaviour within the first game. In order to do this, we explore methods for measuring skill in both a multiplayer and single-player game and methods for extracting appropriate information from the player's behaviour. The resulting predictions can then be used to automatically assign an appropriate difficulty to the player. In a multiplayer environment, we first demonstrate that a player's final rank canbe predicted within the first 30 seconds of a game with a correlation of over 0.8.This process is transferred to a single-player first-person shooter, where our modelis shown to assign difficulties comparable to a player's own assessment of theirskill within the first 30 seconds of a campaign. We argue that these methods forcapturing skill in a first-person shooter are transferable to other genres, and havethe potential to improve difficulty selection systems.
23
Bilodeau, Bethany Jewell. "Appreciative Inquiry and Video Self Modeling Leadership Program| Achieving Skill or Behavior Change." Thesis, Franklin Pierce University, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3604790.
Abstract:
A leadership program was created for students to gain skills and/or change their behavior using Appreciative Inquiry and Video Self Modeling, VSM. In 2011a youth that experiences a disability had been unable to achieve a skill utilizing traditional methods of skill acquisition. He employed the Appreciative Inquiry and VSM leadership program and was able to achieve 100% skill acquisition. Appreciative Inquiry was used to gather information on what makes a participant who experiences a disability feel successful and the theme of the greater organization/class which was independence, provided guidance for examples of success. Videos were created showing students succeeding in activities that they have not yet achieved or participate in with low frequency. These activities were documented as a barrier to success typically in the Individual Education Plan, IEP. Viewing these videos aids the individual in achieving a goal as they viewed this desired future as the present in the majority of cases.
24
Cristancho, Sayra Magnolia. "Quantitative modelling and assessment of surgical motor actions in minimally invasive surgery." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/2835.
Abstract:
The goal of this research was to establish a methodology for quantifying performance of
surgeons and distinguishing skill levels during live surgeries. We integrated three
physical measures (kinematics, time and movement transitions) into a modeling
technique for quantifying performance of surgical trainees. We first defined a new
hierarchical representation called Motor and Cognitive Modeling Diagram for
laparoscopic procedures, which: (1) decomposes ‘tasks’ into ‘subtasks’ and at the very detailed level into individual movements ‘actions’; and (2) includes an explicit cognitive/motor diagrammatic representation that enables to take account of the operative variability as most intraoperative assessments are conducted at the ‘whole procedure’ level and do not distinguish between performance of trivial and complicated aspects of the procedure. Then, at each level of surgical complexity, we implemented specific mathematical techniques for providing a quantitative sense of how far a performance is located from a reference level:
(1) The Kolgomorov-Smirnov statistic to describe the similarity between two
empirical cumulative distribution functions (e.g., speed profiles)
(2) The symmetric normalized Jensen-Shannon Divergence to compare transition
probability matrices
(3) The Principal Component Analysis to identify the directions of greatest variability in a multidimensional space and to reduce the dimensionality of the data using a weight space.
Two experimental studies were completed in order to show feasibility of our proposed
assessment methodology by monitoring movements of surgical tools while: (1) dissecting mandarin oranges, and (2) performing laparoscopic cholecystectomy procedures at the operating room to compare residents and expert surgeons when executing two surgical tasks: exposing Calot’s Triangle and dissecting the cystic duct and artery.
Results demonstrated the ability of our methodology to represent selected tasks using the Motor and Cognitive Modeling Diagram and to differentiate skill levels. We aim to use our approach in future studies to establish correspondences between specific surgical tasks and the corresponding simulations of these tasks, which may ultimately enable us to do validated assessments in a simulated setting, and to test its reliability in differentiating skill levels at the operating room as the number of subjects and procedures increase.
25
Zirn, Lena [Verfasser], and Frank [Akademischer Betreuer] Fischer. "Facilitating skill acquisition with video-based modeling worked examples / Lena Zirn. Betreuer: Frank Fischer." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2015. http://d-nb.info/1079140255/34.
26
Zhu, Zimo. "Techniques for Finite Element Modeling and Remodeling of Bones with Applications to Pig Skulls." University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1512045879980572.
27
McCardle, Lindsay. "The effects of self-modeling on self-regulation in skill acquisition: The self-reflection phase." Thesis, University of Ottawa (Canada), 2008. http://hdl.handle.net/10393/27709.
Abstract:
Dowrick (1999) proposed the method of feedforward self-modeling in which a video is edited to show a higher level of performance than the learner's current ability. In this experiment, the feedforward self-modeling video showed a gymnast performing a combination of two floor skills which they were able to do separately but not yet in combination. Eight gymnasts (7 females, 1 male; M age = 9.9) participated in a pretest, nine intervention sessions and a post test. During the intervention sessions, the gymnasts received a feedforward self-modeling video for one skill combination and no intervention for a control skill combination. I investigated the possible influences of viewing the feedforward self-modeling video on the gymnasts' self-regulatory processes within the context of Zimmerman's (2000) model of self-regulation. There was a specific focus on the self-reflection phase. Thus, the use of self-evaluation criteria, the dimensions of causal attributions for both good and poor performances, self-satisfaction, and use of inferences were measured. Separate ANOVAs showed that feedforward self-modeling and control conditions did not differ for any of the dependent variables. A significant main effect was found for dimension for the Revised Causal Dimension Scale (McAuley, Duncan & Russell, 1992) for both good (F(3,21) = 14.249, p<.001, partial eta2 = .671) and poor performances (F(3,21) = 9.994, p<.001, partial eta2 = .588). Participants made attributions which were internal, unstable and controllable in both cases. Further research is encouraged with feedforward self-modeling interventions in order to determine their impact on self-regulated learning.
28
Knisley, Jenna N. "Optimal Skill Levels for Seru Versus Assembly Line with Augmented Reality Training Considerations." Ohio University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1619183267396289.
29
Joseph, Todd Allen. "The effect of mental practice type on dart-throwing performance." [Tampa, Fla.] : University of South Florida, 2004. http://purl.fcla.edu/fcla/etd/SFE0000509.
30
Ashford, Derek George. "Constraints on skill acquisitions : a meta-analysis of the movement based observational modelling literature." Thesis, Manchester Metropolitan University, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.404545.
Abstract:
The program of work reported within the thesis constitutes the first quantitative analysis of the observational modelling (OM) literature. It was motivated by the major limitations that restrict qualitative reviews. These have been common in the skill acquisition literature (McCullagh et af., 1989; Williams et af., 1999; Williams, 1993). Qualitative reviews typically involve only a limited sample of independent investigations, and selection and subsequent interpretation processes are highly susceptible to various types of biases (Copper and Hedges, 1994). An extensive search of the literature was conducted including (n = 293) sources associated with all types of behaviour modification involving OM. Because the thesis was aimed at understanding the effect of constraints on movement skill acquisition, only modelling effects associated with movement behaviour modification were considered (n = 65). In chapter 1, a qualitative review of the movement based OM literature was included. This revealed that experiments on behaviour modification associated with OM have used various experimental designs (e.g., between and within-groups), and typically movement effect (ME) and/or movement dynamics (MD) outcomes as dependent measures. These qualitative findings provided the rationale for the meta-analyses that followed. In chapter 2, current meta-analytic procedures were reviewed to clarify the protocols required to synthesize overall mean effects of OM treatments from diverse designs. Effect size estimates derived from (n = 69) primary investigations were used within two major meta-analytic summaries. The first review (chap.3) clarified the overall mean treatment effect of OM for ME (0 = 0.27) and MD (0 = 0.77) measures over and above that gained through practice only / discovery learning conditions. Both treatment effects represent significant (p<0.01) modelling benefits over control conditions, with additional benefits clearly evident for MD outcomes. These results are consistent with the Visual Perception Perspective (Scully and Newell, 1985) for OM, and suggest that, primarily, demonstrations convey the MD (i.e. relative motions) required to approximate modelled movement skills. Although, ME (Le., performance outcomes) can benefit, modelling treatment effects are typically more modest, suggesting an increased role of 'practice' in skill acquisition. To quantify task constraint influences during OM a new task classification measure was developed (chapA). The classification used two difficulty components, novelty and complexity, which were defined using 3 and 7 descriptive variables respectively. The inter-rater reliability and test-retest objectivity of each descriptive variable rating produced an intraclass correlation coefficients ranging from r = 0.81 to 1.00 and r = 0.87 to 1.00 respectively. The second review (chap.5) reported the mean treatment effects for high and low movement novelty and complexity for MD and ME modelling outcomes. MD results indicated a marked difference in overall treatment effects gained for high (0 = 1.02) and low (0 = 0.57) novelty. Similar, yet more modest novelty effects were obtained for ME outcomes (Ohigh = 0.42 and Olow = 0.11). These results were in direct contrast to previous predictions and conclusions (Gould, 1978). Results suggest facilitative MD modeling outcomes occurred with increased task novelty. The complexity analyses highlighted no discernable difference in MD treatment effects for high (0 = 0.72) and low (8 = 0.74) movement complexity. ME measures were generally more trivial, but also showed little difference resulting from high (0 = 0.07) or low (0 = 0.12) task complexity. Comparable estimates were obtained for an overall difficulty analysis which combined novelty and complexity components. These results indicated that whilst complexity might be expected to influence OM outcomes, further analysis and refinement of the current complexity classification may be warranted within future research efforts.
31
Stone, Sarah M. "Using Video Modeling Delivered Through an iPod Touch to Teach Purchasing Skill to Students With Severe Cognitive Disabilities." DigitalCommons@USU, 2013. https://digitalcommons.usu.edu/etd/2046.
Abstract:
Video modeling is a recent buzzword in the vocabulary of special educators and other professionals who work with individuals with disabilities. This type of modeling has proven effective in many studies specifically for individuals with autism. Recent studies show the effectiveness of acquiring skills through observing a video recording of a model (themselves or another person) performing the skill correctly. The technique used in this study is video modeling with another individual as the model (VMO). The researchers looked at the acquisition of purchasing skills based on viewing the video model in the grocery store. The VMO was presented using an Apple iPod Touch where the student could easily access the video and use headphones to hear the VMO while shopping in the grocery store.This research involved three high school-aged participants with significant cognitive disabilities who displayed a need for purchasing skills within the grocery store. They were taught seven steps through the VMO in the grocery store. The skills were: (a) select shortest checkout lane, (b) put divider down and place items from the cart on the belt, (c) greet cashier, (d) pay cashier appropriate bill or combination of bills, (e) wait and take change and receipt from cashier, (f) thank cashier, and (g) take bag and carry belongings to the exit. In order to check for generalization of the skill, the participant was taken to different local grocery stores not involved in initial teaching once they acquired mastery at the original grocery store.Results indicated VMO increased responding for all three participants from the beginning of the study for purchasing groceries. All participants generalized the purchasing skills in other grocery stores; however, each participant required additional instruction via VMO or other prompting throughout the study.The results illustrate for educators and researchers that VMO represents a practical method for increasing skills in community settings. This also illustrates the need for VMO to be paired with additional instruction and should not be used as the only mode to teach a skill.
32
Blake, Bruce. "THE EFFECT OF VIDEO MODELING AND SOCIAL SKILL INSTRUCTIONON ON THE SOCIAL SKILLS OF ADOLESCENTS WITH HIGH FUNCTIONING AUTISM AND." Doctoral diss., University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3676.
Abstract:
ABSTRACT Research conducted on video modeling has shown that these strategies are most effective when they include specific strategies to address conversation skills. Social skills research has also shown that teaching social skills to adolescents in group settings may be more effective than presenting them on an individual basis. Adolescents with Aspergers Syndrome (AS) and High functioning Autism (HFA) participated in a12-week Social Skills Training (SST) program. In addition to pre-and post-study measures, conversation skills data were collected before and after the application of the independent variable (video modeling). Follow-up interviews were also conducted with participants, secondary participants, and parents of the primary participants. After a two-week baseline phase, participants attended weekly social skills training and received the treatment of video modeling with videos found on YouTube. This established pre-existing social and conversation skills and enabled the measurement of changes over the course of the 12 week program. After post intervention data were collected, additional data were collected with participants and secondary participants, neuro-typical peers, as a measure of treatment generalization. This study proposed that presenting social skills videos found on YouTube, would be effective in increasing levels of initiation, responses and conversation skills, thereby increasing communication effectiveness and reducing social rejection by peers. Although some gains in conversational skill levels were observed by most participants in the study significant increases in conversation skill levels were not observed in both ASD only group settings or of the ASD neuro-typical mixed group setting.Ed.D.
Department of Child, Family and Community Sciences
Education
Education EdD
33
Sawyer, Rebecca Jo Moore. "Teacher Training: An Examination of Skill Acquisition, Generalization, and Increases in Child Appropriate Behavior." Thesis, University of North Texas, 2000. https://digital.library.unt.edu/ark:/67531/metadc2606/.
Abstract:
The effects of a training package (modeling, role-playing, and feedback) were evaluated using a multiple baseline across skill areas. Two trainers taught two teachers to use basic intervention skills that included components of both discrete trial teaching (DTT) and the Natural Language Paradigm (NLP). Training occurred in the context of one task. Generalization was assessed with two untrained tasks. Teachers' responses in the target task increased following training, as did appropriate responding from the child. Some generalization of the teaching skills occurred. Teachers were instructed to generalize acquired skills as a possible method to promote generalization. The results of these findings and implications for training of ABA providers are discussed.
34
Gokce, Sahin Mine. "The Effect Of Modelling Instruction On High School Students." Phd thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12610108/index.pdf.
Abstract:
The purpose of this study was to investigate the effect of modeling instruction over traditionally designed physics instruction on students&rsquounderstanding of projectile motion concepts and their attitudes towards physics. In addition, the effects of gender difference on their understanding of projectile motion concepts and attitudes towards physics were explored. Furthermore, students&rsquo
views on the nature of science were searched. The subjects of this study included 88 tenth grade students of four classes instructed by two teachers in a private high school. One of two classes of each teacher was randomly assigned to experimental group and other classes formed control group. The modeling instruction was applied in the experimental group to teach the topic of projectile motion, it was taught with traditionally designed physics instruction in control group. Projectile Motion Concept Test, Attitude Scale towards Physics, Science Process Skill Test, and Views on Science-Technology-Society test were administered to both groups. In addition, student interviews and classroom observations were conducted. The hypotheses of the research were tested by using ANCOVA and two-way ANOVA. The results revealed that the mean score of experimental group students&rsquo
on both concept test and attitude scale was significantly higher than the mean score of control group students. Furthermore, gender was not a significant factor affecting the concept acquisition related to projectile motion and students&rsquo
attitudes towards physics. However, science process skill was determined as a strong predictor in conceptual understanding. Lastly, experimental group students had more realistic views on some basic tenets of nature of science.
35
Olutuase, Samuel Oladipo. "Modelling the effect of entrepreneurship education on entrepreneurial mindset, skill and intentions: Empiraical evidence from undergraduates in Nigeria." University of the Western Cape, 2017. http://hdl.handle.net/11394/6280.
Abstract:
Philosophiae Doctor - PhD (School of Business and Finance)Entrepreneurial firms, entrepreneurial capital, entrepreneurial ecosystem and entrepreneurial economy are a few terminologies that have emerged since the resurgence of entrepreneurship, arising from the 1990's entrepreneurial revolution in the United States of America. Entrepreneurship education, a paradigm shift from the conventional, has been identifies as being critical to fostering entrepreneurship, building entrepreneurial capital, growing entrepreneurial economy and ultimately delivering sustainable economic growth and developmend for any nation - emerging or developed. From America to Africa, entrepreneurship modules with varies objectives and designs have multiplied in the last decade.
36
Schaab, Nancy A. "Comparison of two modes of instruction and two models of skill practice in behavior modeling training : an exploration of Graf's generation effect in learning /." The Ohio State University, 1985. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487260859496393.
37
Woods, Carl T. C. "The development of an objective multi-dimensional approach to talent identification in junior Australian football." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2015. https://ro.ecu.edu.au/theses/1672.
Abstract:
Talent identification (TID) is a pertinent component of the sports science discipline given the considerable influence it may have within the pursuit of excellence. Thus, research has attempted to identify the determinants of a talented performance through the use of objective testing procedures. However, many of these ‘traditional’ approaches have been operationalised by mono-dimensional objective physical performance tests that do not inherently account for the multi-dimensional requisites of game-play, particularly within a team sporting context. This is problematic when attempting to identify talent, as a successful performance in team sports is often the combination of physical, technical and tactical elements. For example, a physically inferior junior may still succeed against their physically superior counterparts given additional technical and tactical skills; commonly referred to as a compensation phenomenon. Hence, forecasting longitudinal performance based upon one element of effective play (e.g. physical) will likely lead to an unsubstantiated and biased identification.
Despite the aforementioned, TID practices in junior Australian football (AF) are predominately facilitated by physically biased objective performance tests. Given the combative nature of game-play, physicality is an important attribute, but solely basing identification and selection on isolated physical attributes can be misleading given the previously mentioned compensation phenomenon. This mono-dimensionality is somewhat expected as to date there is a scarcity of objective tests measuring the multidimensional characteristics of AF game-play. Thus, through the consolidation of a number of theoretical concepts and recommendations proposed within the literature, this thesis aimed to develop a multi-dimensional objective approach to TID in junior AF, and in doing so, identify the determinants of a talented performance.
To address this aim, objective physical, technical and tactical measurements were taken on both talent identified and non-talent identified junior AF players through the use of representative performance tests. Indeed, this reflected the first stage of the Expert Performance Approach (Ericsson & Williams, 1991; Williams & Ericsson, 2005) and the Model of a Skilful Player (Launder, 2001). Throughout each research study, talent identified players were defined through participation within the West Australian Football League (WAFL) State Under 18 (U18) Academy (an elite talent development program), whilst non-talent identified players were randomly chosen from the remaining cohort of WAFL U18 players not participating in the State Academy program. Thus, a cross-sectional observational research design was employed for each experimental procedure used throughout this thesis. It is of note that the first three studies utilised players from the 2013 sample, whilst the fourth research study utilised players from the 2014 sample.
In the first of four research studies, a range of sport specific physical characteristics were found to differ between talent identified and non-talent identified junior AF players. However, a binary logistic regression model indicated that it was the measurements of standing height, lower body power and maximal aerobic capacity that provided the greatest prediction of talent, and thus important physical determinants of talent in AF at an U18 level.
The second study investigated if measurements of technical skill could be used to accurately identify talent in junior AF. Despite the range of technical skills required in AF, the two modes of ball disposal (kicking and handballing) have been deemed critical for success based upon recent research (Parrington, Ball, MacMahon, 2013; Sullivan et al., 2014). Consequently, two representative skill tests were described; the Australian Football Kicking (AFK) test and the Australian Football Handballing (AFHB) test. Results indicated that the majority of the talent identified players possessed superior ball disposal skills in comparison to their non-talent identified counterparts. Specifically, measures of accuracy and ball speed on both the dominant and non-dominant sides reflected the strongest prediction of talent for the AFK test, and measures of accuracy on both dominant and non-dominant sides reflected the strongest prediction of talent for the AFHB test. These results reinforced the construct of each test, and highlighted their effectiveness for use as an objective TID tool in AF.
Research had yet to investigate if decision-making skill was predictive of talent in junior AF despite its suggested importance for the exhibition of an expert performance in the game. The third study in this research series attempted to fill this remaining gap and objectively quantify decision-making skill through the use of a video-based decision-making task. In order to construct such a task, video footage was obtained from the Australian Football League (AFL) using an aerial behind-the-goal camera perspective. Through the use of an expert coaching panel, 26 clips out of an initial sample of 52 were deemed applicable, as each consisted of approximately three to five possible decision-making options. Results indicated that the talent identified players performed the task more accurately in comparison to their non-talent identified counterparts, and was thus a valuable objective tool for identifying talent at an U18
level.
The fourth and final study in this research series investigated if the application of a multi-dimensional battery of objective performance tests provided more accurate TID in AF when compared to isolated performance measures. The construction of this test battery was informed by the results of studies one, two and three, but to ensure the translation of this test battery, it was applied to the 2014 U18 cohort, not the 2013 cohort which was done in the previous studies. However, the definition of talent identified and non-talent identified remained consistent with the previous studies. Results indicated that the majority of the talent identified players possessed a superior combination of physical, technical and tactical characteristics in comparison to their non-talent identified counterparts. Specifically, a receiver operating curve indicated a classification accuracy of 95% when summating the total scores obtained for each physical, technical and tactical test. This classification accuracy supports the implementation of multi-dimensional objective designs over the traditional monodimensional designs when attempting to identify talent in team sporting contexts.
This thesis was motivated by the need to enhance the accuracy and reliability of current TID practices in AF by developing an objective multi-dimensional approach. In doing so, it contributes an important body of research to the study of TID by providing a conceptually translatable means in which the development of such an approach can be undertaken in other team sports.
38
Donnelly, Clayton. "A multi-group structural equation modelling investigation of the measurement invariance of the Campbell Interest and Skill Survey (CISS) across gender groups in South Africa." Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/2387.
Abstract:
Thesis (MComm (Industrial Psychology))--University of Stellenbosch, 2009.ENGLISH ABSTRACT: The choice of career path could create a stressful situation for many individuals. Researchers seem to agree that if a person is able to find fit between what they would like to do and what a job (work environment) involves then a person is likely to perform their chosen occupation well. Interest assessment is a method that assists in making personal and organisational career related decisions. The Campbell Interest and Skill Survey (CISS, Campbell, Hyne & Nilsen, 1992) is a well-known interest assessment instrument that can be used for such decisions. Even though interest assessment can assist, these instruments have been criticised for being gender biased and typically forcing people into stereotypical gendered type occupations. Bias is indicated as nuisance factors that threaten the validity of cross-group (cultural) comparisons (Van de Vijver & Leung, 1997). These nuisance factors could be due to construct bias, method bias and/or item bias. Therefore, due to the importance of the decisions made, it would seem essential that the information provided by test results apply equally across different reference groups – this would imply equivalent measurement. Equivalence is achieved at three levels: Configural, metric and scalar (Vandenberg & Lance, 2000; Vandenberg, 2002). Full measurement invariance (achieved when scalar invariance is found) implies the ability to compare observed scores directly. By making use of confirmatory factor analytic techniques suggested by Vandenberg and Lance (2000), increasing constraints of equivalence were proposed for the CISS measurement model. While adequate model fit was found for the CISS Basic scales, the sample size did not afford independent gender sample confirmatory factor analyses (CFAs) and consequent measurement invariance tests to be conducted on the Basic scales. The CISS Orientation scales were then subjected to CFA on the combined gender sample and then were subjected to independent CFAs on the separate gender samples. Unfortunately poor model fit was found at this global level of measurement in the CISS. This prevented the researcher from completing the necessary measurement invariance tests on the Orientation scales for the CISS. The implications of the results are discussed, limitations are indicated and areas for further research are highlighted.
AFRIKAANSE OPSOMMING: Die maak van ‘n loopbaankeuse kan spanning veroorsaak in baie mense. Dit wil voorkom of navorsers saamstem dat indien ‘n person se werklike beroep ooreenstem met dit wat hy/sy graag sou wou doen – dan sal die persoon waarskynlik goed presteer in die gekose beroep. Die benutting van belangstellingsvraelyste kan individue help om effektiewe persoonlike en beroepsgerigte keuses te maak. Die “Campbell Interest and Skill Survey” (CISS, Campbell, Hyne & Nilsen, 1992) is ‘n bekende belangstellingsvraelys wat gebruik kan word om ondersteuning te bied om bogenoemde keuses te maak. Alhoewel belangstellingsvraelyste oor die algemeen waardevolle hulpbronne is in die maak van beroepskeuses, is hierdie vraelyste al gekritiseer dat hulle sydig kan wees op grond van geslag en as sulks mense kan lei om geslagsgetipeerde beroepskeuses te maak. “Sydigheid” in toetse kan beskryf word as “lastige” faktore wat die geldigheid van kruiskulturele vergelykings bedreig (Van de Vijver & Leung, 1997). Hierdie faktore kan veroorsaak word deur konstruksydigheid, metodesydigheid en/of itemsydigheid. Dit is dus noodsaaklik dat die informasie wat verskaf word deur die toetsresultate dieselfde betekenis moet hê oor al die verskillende verwysingsgroepe en dit noodsaak ekwivalente meting. Ekwivalensie kan bereik word op drie vlakke: konfiguraal, metries en skalêr (Vandenberg & Lance, 2000; Vandenberg, 2002). Volle invariansie van meting (wat bereik word wanneer skalêre invariansie bevind word) impliseer dat waargenome metings direk met mekaar vergelyk kan word. Deur gebruik te maak van bevestigende faktoranalitiese tegnieke voorgestel deur Vandenberg en Lance (2000), is toenemende ekwivalensiebeperkinge voorgestel vir die “CISS” metingsmodel. Alhoewel ’n bevredigende passing gevind is vir die “CISS Basic scales” model, het die grootte van die steekproef nie toegelaat dat die “CISS Basic scales” model onafhanklik op die twee geslagsgroepe gepas word nie en ook nie toegelaat dat die metingsinvariansie van die model oor die twee geslagsgroepe ondersoek word nie. Die “CISS Orientation scales” is toe blootgestel aan bevestigende faktorontleding op die gekombineerde geslagsteekproef en asook op die onderskeie geslagsgroepe. Op hierdie globale vlak kon daar egter nie bevredigende modelpassing gevind word nie. Die gebrekkige modelpassing het gevolglik die navorser verhoed om enige verdere metingsvariansie toetse op die “Orientation scales” te doen. Die implikasies van die resultate word bespreek, beperkinge word aangedui en verdere moonlike navorsingsgebiede word uitgelig.
39
Garci, Maroua. "Simulation multi-physiques de circuits intégrés pour la fiabilité." Thesis, Strasbourg, 2016. http://www.theses.fr/2016STRAD020/document.
Abstract:
Cette thèse porte sur le thème général de la fiabilité des circuits microélectroniques. Le but de notre travail fut de développer un outil de simulation multi-physiques pour la conception des circuits intégrés fiables qui possède les caractéristiques innovatrices suivantes : • (i) L’intégration dans un environnement de conception microélectronique standard, tel que l’environnement Cadence® ; • (ii) La possibilité de simulation, sur de longues durées, du comportement des circuits CMOS analogiques en tenant compte du phénomène de vieillissement ; • (iii) La simulation de plusieurs physiques (électrique-thermique-mécanique) couplées dans ce même environnement de CAO en utilisant la méthode de simulation directe. Ce travail de thèse a été réalisé en passant par trois grandes étapes traduites par les trois parties de ce manuscritThis thesis was carried out under the theme of the microelectronics Integrated Circuits Reliability. The aim of our work was to develop a multi-physics simulation tool for the design of reliable integrated circuits. This tool has the following innovative features : • (i) The integration in a standard microelectronics design environment, such as the Cadence® environment ;• (ii) The possibility of efficient simulation, over long periods, of analog CMOS circuits taking into account the aging henomenon ; • (iii) The simulation of multiple physical behaviours of ICs (electrical-thermalmechanical) coupled in the same environment using the direct simulation method. This work was carried out through three main stages detailed in the three parts of this Manuscript
40
Verdi, Marcio. "Prediçao de distribuíção de espécies arbustivo-arbóreas no sul do Brasil." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2013. http://hdl.handle.net/10183/115515.
Abstract:
Em vista das mudanças ambientais em nível global, disponibilizar informações ecológicas e buscar uma melhor compreensão dos fatores e processos que moldam a distribuição de espécies, é uma iniciativa importante para o planejamento de ações de conservação. Neste contexto, a importância e carência de informações sobre a distribuição geográficas das espécies nos motivaram a predizer a distribuição potencial de arbustos e árvores das famílias Lauraceae e Myrtaceae na Floresta Atlântica, no sul do Brasil. Modelos lineares generalizados (GLM) foram usados para ajustar modelos preditivos com os registros de ocorrência de 88 espécies em função de variáveis ambientais. As variáveis preditoras foram selecionadas com base no menor critério de informação de Akaike corrigido. Nós avaliamos o desempenho dos modelos usando o método de validação cruzada (10-fold) para calcular a habilidade estatística verdadeira (TSS) e a área sob a curva característica do operador receptor (AUC). Nós usamos GLM para testar a influência da área de ocorrência estimada, do número de registros das espécies e da complexidade dos modelos sobre a TSS e a AUC. Nossos resultados mostraram que as variáveis climáticas governam amplamente a distribuição de espécies, mas as variáveis que captam as variações ambientais locais são relativamente importantes na área de estudo. A TSS foi significativamente influenciada pelo número de registros e complexidade dos modelos, enquanto a AUC sofreu com o efeito de todos os três fatores avaliados. A interação entre estes fatores é uma questão importante e a ser considerada em novas avaliações sobre ambas medidas e com diferentes técnicas de modelagem. Nossos resultados também mostraram que as distribuições de algumas espécies foram superestimadas e outras corresponderam bem com a ocorrência por nós conhecida. Efetivamente nossos resultados têm fundamentos para embasar novos levantamentos de campo, a avaliação de áreas prioritárias e planos de conservação, além de inferências dos efeitos de mudanças ambientais sobre as espécies da Mata Atlântica.In view of environmental change on a global level, providing ecological information and getting a better understanding of the factors and processes that shape species distribution is an important initiative for planning conservation actions. In this context, the importance and lack of information about the geographical distribution of species motivated us to predict the potential species distribution of shrubs and trees of the family Lauraceae and Myrtaceae, in the Atlantic Forest in southern Brazil. Generalized linear models (GLM) were used to fit predictive models with records of occurrence of 88 species according to environmental variables. Predictor variables were selected based on the lowest corrected Akaike information criterion. We evaluate the performance of the models using the method of cross-validation (10-fold) to calculate the true skill statistic (TSS) and area under the receiver operator characteristic curve (AUC). We used GLM to test the influence of the area of occurrence estimated, the number of records of the species and the complexity of the models on the TSS and AUC. Our results show that climatic variables largely govern the distribution of species, but the variables that capture the local environmental variations are relatively important in the study area. The TSS was significantly influenced by the number of records and complexity of models while the AUC suffered from the effect of all three evaluated factors. The interaction between these factors is an important issue and be considered for new reviews on both measures and with different modeling techniques. Our results also showed that the distributions of some species were overestimated and other corresponded well with the occurrence known to us. Indeed our results have foundations to support new field surveys, assessment of priority areas and conservation plans, and inferences of the effects of environmental change on species of the Atlantic Forest.
41
Spence-Cochran, Kimberly Gen. "AN INVESTIGATION OF THE PROFICIENCY LEVEL OF HIGH SCHOOL STUDENTS WITH AUTISM AND MENTAL RETARDATION WITHIN COMMUNITY-BASED JOB SETTINGS: THE RELATIONSHIP BETWEEN THE USE OF A HAND-HELD COMPUTER COMPARED TO STAFF MODELING FOR ACCURATE NOVEL JOB SKILL ACQUISITION AND STUDENT LEARNING." Doctoral diss., University of Central Florida, 2004. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4386.
Abstract:
This study examined the effects and efficacy of two vocational instructional interventions - a Hand-Held Computer intervention versus a Staff Model intervention - as vocational instructional tools for high school students with autism and mental retardation. Specifically, the study analyzed the effects of these two treatments on the completion of authentic novel job tasks within a local department store. This research indicated the provision of specific technology as an instructional model positively influenced participants' ability to: accurately complete tasks, exercise increased independence during task completion, reduce problematic behavior during task completion, and lower necessary staff prompts during task completion. The use of technology to support individuals with severe disabilities has the potential to increase their level of independence and accuracy of job completion within community-based settings. Five high school students with autism and mental retardation participated in this study, which compared the use of a palm-top computer with a traditional staff model during the completion of eighteen novel job tasks within various departments of a large department store. Five of eight variables subjected to ANOVA and independent t-test analyses demonstrated significance.Ph.D.
Department of Child, Family and Community Sciences
Education
Child, Family, and Community Sciences
42
Mavridis, Panagiotis. "Utilisation d'une hiérarchie de compétences pour l'optimisation de sélection de tâches en crowdsourcing." Thesis, Rennes 1, 2017. http://www.theses.fr/2017REN1S060/document.
Abstract:
Des nombreuses applications participatives, commerciales et académiques se appuient sur des volontaires ("la foule") pour acquérir, désambiguiser et nettoyer des données. Ces applications participatives sont largement connues sous le nom de plates-formes de crowdsourcing où des amateurs peuvent participer à de véritables projets scientifiques ou commerciaux. Ainsi, des demandeurs sous-traitent des tâches en les proposant sur des plates-formes telles que Amazon MTurk ou Crowdflower. Puis, des participants en ligne sélectionnent et exécutent ces tâches, appelés microtasks, acceptant un micropaiement en retour. Ces plates-formes sont confrontées à des défis tels qu'assurer la qualité des réponses acquises, aider les participants à trouver des tâches pertinentes et intéressantes, tirer parti des compétences expertes parmi la foule, respecter les délais des tâches et promouvoir les participants qui accomplissent le plus de tâches. Cependant, la plupart des plates-formes ne modélisent pas explicitement les compétences des participants, ou se basent simplement sur une description en terme de mots-clés. Dans ce travail, nous proposons de formaliser les compétences des participants au moyen d'une structure hiérarchique, une taxonomie, qui permet naturellement de raisonner sur les compétences (détecter des compétences équivalentes, substituer des participants, ...). Nous montrons comment optimiser la sélection de tâches au moyen de cette taxonomie. Par de nombreuses expériences synthétiques et réelles, nous montrons qu'il existe une amélioration significative de la qualité lorsque l'on considère une structure hiérarchique de compétences au lieu de mots-clés purs. Dans une seconde partie, nous étudions le problème du choix des tâches par les participants. En effet, choisir parmi une interminable liste de tâches possibles peut s'avérer difficile et prend beaucoup de temps, et s’avère avoir une incidence sur la qualité des réponses. Nous proposons une méthode de réduction du nombre de propositions. L'état de l'art n'utilise ni une taxonomie ni des méthodes de classement. Nous proposons un nouveau modèle de classement qui tient compte de la diversité des compétences du participant et l'urgence de la tâche. À notre connaissance, nous sommes les premiers à combiner les échéances des tâches en une métrique d'urgence avec la proposition de tâches pour le crowdsourcing. Des expériences synthétiques et réelles montre que nous pouvons respecter les délais, obtenir des réponses de haute qualité, garder l'intérêt des participants tout en leur donnant un choix de tâches cibléA large number of commercial and academic participative applications rely on a crowd to acquire, disambiguate and clean data. These participative applications are widely known as crowdsourcing platforms where amateur enthusiasts are involved in real scientific or commercial projects. Requesters are outsourcing tasks by posting them on online commercial crowdsourcing platforms such as Amazon MTurk or Crowdflower. There, online participants select and perform these tasks, called microtasks, accepting a micropayment in return. These platforms face challenges such as reassuring the quality of the acquired answers, assisting participants to find relevant and interesting tasks, leveraging expert skills among the crowd, meeting tasks' deadlines and satisfying participants that will happily perform more tasks. However, related work mainly focuses on modeling skills as keywords to improve quality, in this work we formalize skills with the use a hierarchical structure, a taxonomy, that can inherently provide with a natural way to substitute tasks with similar skills. It also takes advantage of the whole crowd workforce. With extensive synthetic and real datasets, we show that there is a significant improvement in quality when someone considers a hierarchical structure of skills instead of pure keywords. On the other hand, we extend our work to study the impact of a participant’s choice given a list of tasks. While our previous solution focused on improving an overall one-to-one matching for tasks and participants we examine how participants can choose from a ranked list of tasks. Selecting from an enormous list of tasks can be challenging and time consuming and has been proved to affect the quality of answers to crowdsourcing platforms. Existing related work concerning crowdsourcing does not use either a taxonomy or ranking methods, that exist in other similar domains, to assist participants. We propose a new model that takes advantage of the diversity of the parcipant's skills and proposes him a smart list of tasks, taking into account their deadlines as well. To the best of our knowledge, we are the first to combine the deadlines of tasks into an urgency metric with the task proposition for knowledge-intensive crowdsourcing. Our extensive synthetic and real experimentation show that we can meet deadlines, get high quality answers, keep the interest of participants while giving them a choice of well selected tasks
43
Millear, Prudence M. R. "Adapting to the work-life interface : the influence of individual differences, work and family on well-being, mental health and work engagement." Thesis, Queensland University of Technology, 2010. https://eprints.qut.edu.au/39183/1/Prudence_Millear_Thesis.pdf.
Abstract:
Bronfenbrenner.s Bioecological Model, expressed as the developmental equation, D f PPCT, is the theoretical framework for two studies that bring together diverse strands of psychology to study the work-life interface of working adults. Occupational and organizational psychology is focused on the demands and resources of work and family, without emphasising the individual in detail. Health and personality psychology examine the individual but without emphasis on the individual.s work and family roles. The current research used Bronfenbrenner.s theoretical framework to combine individual differences, work and family to understand how these factors influence the working adult.s psychological functioning. Competent development has been defined as high well-being (measured as life satisfaction and psychological well-being) and high work engagement (as work vigour, work dedication and absorption in work) and as the absence of mental illness (as depression, anxiety and stress) and the absence of burnout (as emotional exhaustion, cynicism and professional efficacy). Study 1 and 2 were linked, with Study 1 as a cross-sectional survey and Study 2, a prospective panel study that followed on from the data used in Study1. Participants were recruited from a university and from a large public hospital to take part in a 3-wave, online study where they completed identical surveys at 3-4 month intervals (N = 470 at Time 1 and N = 198 at Time 3). In Study 1, hierarchical multiple regressions were used to assess the effects of individual differences (Block 1, e.g. dispositional optimism, coping self-efficacy, perceived control of time, humour), work and family variables (Block 2, e.g. affective commitment, skill discretion, work hours, children, marital status, family demands) and the work-life interface (Block 3, e.g. direction and quality of spillover between roles, work-life balance) on the outcomes. There were a mosaic of predictors of the outcomes with a group of seven that were the most frequent significant predictors and which represented the individual (dispositional optimism and coping self-efficacy), the workplace (skill discretion, affective commitment and job autonomy) and the work-life interface (negative work-to-family spillover and negative family-to-work spillover). Interestingly, gender and working hours were not important predictors. The effects of job social support, generally and for work-life issues, perceived control of time and egalitarian gender roles on the outcomes were mediated by negative work-to-family spillover, particularly for emotional exhaustion. Further, the effect of negative spillover on depression, anxiety and work engagement was moderated by the individual.s personal and workplace resources. Study 2 modelled the longitudinal relationships between the group of the seven most frequent predictors and the outcomes. Using a set of non-nested models, the relative influences of concurrent functioning, stability and change over time were assessed. The modelling began with models at Time 1, which formed the basis for confirmatory factor analysis (CFA) to establish the underlying relationships between the variables and calculate the composite variables for the longitudinal models. The CFAs were well fitting with few modifications to ensure good fit. However, using burnout and work engagement together required additional analyses to resolve poor fit, with one factor (representing a continuum from burnout to work engagement) being the only acceptable solution. Five different longitudinal models were investigated as the Well-Being, Mental Distress, Well-Being-Mental Health, Work Engagement and Integrated models using differing combinations of the outcomes. The best fitting model for each was a reciprocal model that was trimmed of trivial paths. The strongest paths were the synchronous correlations and the paths within variables over time. The reciprocal paths were more variable with weak to mild effects. There was evidence of gain and loss spirals between the variables over time, with a slight net gain in resources that may provide the mechanism for the accumulation of psychological advantage over a lifetime. The longitudinal models also showed that there are leverage points at which personal, psychological and managerial interventions can be targeted to bolster the individual and provide supportive workplace conditions that also minimise negative spillover. Bronfenbrenner.s developmental equation has been a useful framework for the current research, showing the importance of the person as central to the individual.s experience of the work-life interface. By taking control of their own life, the individual can craft a life path that is most suited to their own needs. Competent developmental outcomes were most likely where the person was optimistic and had high self-efficacy, worked in a job that they were attached to and which allowed them to use their talents and without too much negative spillover between their work and family domains. In this way, individuals had greater well-being, better mental health and greater work engagement at any one time and across time.
44
Sao, Pedro Michael A. "Real-time Assessment, Prediction, and Scaffolding of Middle School Students’ Data Collection Skills within Physical Science Simulations." Digital WPI, 2013. https://digitalcommons.wpi.edu/etd-dissertations/168.
Abstract:
Despite widespread recognition by science educators, researchers and K-12 frameworks that scientific inquiry should be an essential part of science education, typical classrooms and assessments still emphasize rote vocabulary, facts, and formulas. One of several reasons for this is that the rigorous assessment of complex inquiry skills is still in its infancy. Though progress has been made, there are still many challenges that hinder inquiry from being assessed in a meaningful, scalable, reliable and timely manner. To address some of these challenges and to realize the possibility of formative assessment of inquiry, we describe a novel approach for evaluating, tracking, and scaffolding inquiry process skills. These skills are demonstrated as students experiment with computer-based simulations. In this work, we focus on two skills related to data collection, designing controlled experiments and testing stated hypotheses. Central to this approach is the use and extension of techniques developed in the Intelligent Tutoring Systems and Educational Data Mining communities to handle the variety of ways in which students can demonstrate skills. To evaluate students' skills, we iteratively developed data-mined models (detectors) that can discern when students test their articulated hypotheses and design controlled experiments. To aggregate and track students' developing latent skill across activities, we use and extend the Bayesian Knowledge-Tracing framework (Corbett & Anderson, 1995). As part of this work, we directly address the scalability and reliability of these models' predictions because we tested how well they predict for student data not used to build them. When doing so, we found that these models demonstrate the potential to scale because they can correctly evaluate and track students' inquiry skills. The ability to evaluate students' inquiry also enables the system to provide automated, individualized feedback to students as they experiment. As part of this work, we also describe an approach to provide such scaffolding to students. We also tested the efficacy of these scaffolds by conducting a study to determine how scaffolding impacts acquisition and transfer of skill across science topics. When doing so, we found that students who received scaffolding versus students who did not were better able to acquire skills in the topic in which they practiced, and also transfer skills to a second topic when was scaffolding removed. Our overall findings suggest that computer-based simulations augmented with real-time feedback can be used to reliably measure the inquiry skills of interest and can help students learn how to demonstrate these skills. As such, our assessment approach and system as a whole shows promise as a way to formatively assess students' inquiry.
45
Scarfe, Bradley Edward. "Oceanographic Considerations for the Management and Protection of Surfing Breaks." The University of Waikato, 2008. http://hdl.handle.net/10289/2668.
Abstract:
Although the physical characteristics of surfing breaks are well described in the literature, there is little specific research on surfing and coastal management. Such research is required because coastal engineering has had significant impacts to surfing breaks, both positive and negative. Strategic planning and environmental impact assessment methods, a central tenet of integrated coastal zone management (ICZM), are recommended by this thesis to maximise surfing amenities. The research reported here identifies key oceanographic considerations required for ICZM around surfing breaks including: surfing wave parameters; surfing break components; relationship between surfer skill, surfing manoeuvre type and wave parameters; wind effects on waves; currents; geomorphic surfing break categorisation; beach-state and morphology; and offshore wave transformations. Key coastal activities that can have impacts to surfing breaks are identified. Environmental data types to consider during coastal studies around surfing breaks are presented and geographic information systems (GIS) are used to manage and interpret such information. To monitor surfing breaks, a shallow water multibeam echo sounding system was utilised and a RTK GPS water level correction and hydrographic GIS methodology developed. Including surfing in coastal management requires coastal engineering solutions that incorporate surfing. As an example, the efficacy of the artificial surfing reef (ASR) at Mount Maunganui, New Zealand, was evaluated. GIS, multibeam echo soundings, oceanographic measurements, photography, and wave modelling were all applied to monitor sea floor morphology around the reef. Results showed that the beach-state has more cellular circulation since the reef was installed, and a groin effect on the offshore bar was caused by the structure within the monitoring period, trapping sediment updrift and eroding sediment downdrift. No identifiable shoreline salient was observed. Landward of the reef, a scour hole ~3 times the surface area of the reef has formed. The current literature on ASRs has primarily focused on reef shape and its role in creating surfing waves. However, this study suggests that impacts to the offshore bar, beach-state, scour hole and surf zone hydrodynamics should all be included in future surfing reef designs. More real world reef studies, including ongoing monitoring of existing surfing reefs are required to validate theoretical concepts in the published literature.
46
Chen, Tzu-Yang, and 陳子揚. "Acceleration Analysis of Dummy Skull Modeling." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/9hv28v.
Abstract:
碩士國立臺灣大學
醫學工程學研究所
107
There are three systems responsible for the balance of a human body: proprioception, vision, and the vestibular system. If the vestibular system is abnormal, it is not possible for anyone to keep well balanced. A diagnostic tool which is named ocular vestibular evoked myogenic potential (oVEMP) examination was developed to evaluate the function of the vestibular system at the end of the 20th century. The process of examination is to artificially generate vibration waves on the head, so that the otolithic organs in the vestibule receive linear acceleration changes, and then by vestibulo-ocular reflex (VOR), the extraocular muscles are subjected to changes in myogenic potential, and the vestibular system function is evaluated by analyzing the surface myogenic potential response. However, many issues of oVEMP remain to be clarified. For example, the position of the head vibration is not suitable for all subjects, and the changes in the induced myogenic potential are not universal. The above problems may involve differences in head structure, resulting in the differences of acceleration changes received by the vestibule. To clarify the above problems, there are two main purposes in this study, firstly to design a system that can generate vibration and measure acceleration, and secondly to explore the geometric factors affecting acceleration in a simplified head dummy model. When the factor is changed quantitatively, the corresponding change of acceleration is measured. In this study a complete platform that is composed of a commercial vibrator and a data acquisition system has been implemented. Also a head dummy model that the structure of frontal sinus in it can be changed has been designed. By analyzing the experimental results, this study proposes a possible hypothesis that the vibration position is the main factor that can influence acceleration changes, and the change of the frontal sinus is a minor factor. This result can provide reference for future research in related fields.
47
Liao, Chun-Yu, and 廖俊宇. "Facial Modeling and Animation based on Muscle and Skull." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/29953458774221570684.
Abstract:
碩士國立清華大學
資訊工程學系
90
Animating lifelike human facial expression is a challenging task in computer graphics. There are two major unsolved problems in it. One is how to construct lifelike human facial models and another is how to animate these models. Traditionally, facial models have been build painstakingly by manual digitization and animated by ad hoc parametrically controlled facial mesh deformations. More recently, the 3D scanner has been used to digitize facial models and they have achieved more realistic animation through the dynamic simulation of facial tissues and muscles. However, the facial models which from 3D scanning still required user assistance to construct individual facial models suitable for animating facial expression. In this thesis, we present a construction and deformation method for head models with anatomical structure, suitable for real-time facial animation. Based on our facial modeling method, the skull is equipped with landmarks and skin thickness data of facial reconstruction and has the corresponding landmarks on skin, which allows us to deform the skull and skin in anthropometrically ways. We also have the muscle attachment points on skull and insertion points on skin, which allows us to automatically construct muscles. Finally, some feature points of MPEG4 on skin are used to deform our model to fit the individual facial model. On any deformed model, the underlying muscle and bone structure are adapted as well, such that the model is animatable using the same muscle contraction parameters. We also use these muscles to achieve the expression retargeting and editing. Moreover, we show that the advantages of our algorithm are not only to reuse expression data but also to generate new expression data if muscle model is applied.
48
Samavedam, Krishna C. "Modeling the Mechanical Morphospace of Neotropical Leaf-nosed Bat Skull: A 3d Parametric Cad and Fe Study." 2011. https://scholarworks.umass.edu/theses/715.
Abstract:
In order to understand the relationship between feeding behavior and the evolution of mammalian skull form, it is essential to evaluate the impact of bite force over large regions of skull. There are about 1,100 bat species worldwide, which represent about 20% of all classified mammal species. Hence, a study in the evolution of bat skull form may provide general understanding of the overall evolution of skull form in mammals. These biomechanical studies are generally performed by first building solid Finite Element (FE) models of skull from micro CT scans. This process of building FE models from micro CT scans is both tedious and time consuming. Therefore a new approach is developed in this research project to build these FE models quickly and efficiently.
I have used SolidWorks to build a parameterized, three dimensional surface CAD model of a skull of the short-tailed fruit bat, Carollia perspicillata, by using coordinate data from an STL model of the species. The overall shape of this model closely resembled that of solid model of C. perspiciallata constructed from micro CT scans. Finite element analyses of the solid and surface models yielded comparable results in terms of magnitude and distribution of von Mises stress and mechanical advantage. Using this parametric surface model, the FE plate or shell element models of different bat species were generated by varying two parameters, palate length and palate width. Parametric analyses were performed on these FE plate models of skulls and response surfaces of performance criteria: von Mises stress, strain energy and mechanical advantage were generated by varying the input parameters. After generating response surfaces, species of bats from the morphologically diverse family of New World leaf-nosed bats (Family Phyllostomidae) were overlain on these response surfaces to determine which portions of the performance design space (palate length X width) are and are not occupied. These plots serve as a foundation for understanding the affect of different performance criteria on the evolution of bat skull form.
49
CONTI, JACOPO. "Evolution of cranio-dental features and distribution of brown bear (Ursus arctos L., 1758) in Europe." Doctoral thesis, 2019. http://hdl.handle.net/11573/1240525.
Abstract:
The study of the fossil remains of the brown bear (Ursus arctos, L. 1758) of the Pleistocene has always been extremely interesting for the vertebrate paleontologists. The discovery of bear material in different sites (fluvio-lacustrine and cave deposits), and the study of the various ecological adaptations developed in conjunction with the speloid forms (Ursus deningeri Reichenau, 1906, Ursus spelaeus Rosenmǖller, 1794) has been crucial for the achievement of palaeoecological necessary schemes for the reconstruction of the European paleoterritory.
However, most of the oldest specimens (Middle and Early Pleistocene), presents uncertain taxonomical attribution, making the origin and paleodistribution of the brown bear in Europe still unclear, just like its first occurrence in Italy (Azzaroli, 1983; Rabeder, Pacher, & Withalm, 2010; Wagner, 2010). Similarly, regarding the Late Pleistocene, the relative scarcity of fossil brown bear material in comparison with those of cave bear, and the poor presence of international scientific documentation, often make the morphological distinction between the two evolutionary lines very complicated, especially regarding the Italian territory.
Currently, the brown bear is unequally distributed throughout Europe; in Italy two distinct populations are present, one in the Alps (Ursus arctos arctos L. 1758) and another which is endemic of the Central Apennine region (Ursus arctos marsicanus, Altobello 1921).
The latter, given its peculiar morphological characteristics of the skull (similar to those of the speleoid forms), has been the subject of many studies. However, we do not have a clear framework about the dynamics of its isolation or its origin (Colangelo, et al., 2012; Meloro, Guidarelli, Colangelo, Ciucci, & Loy, 2017; Benazzo, et al., 2017).
The work carried out during the thesis include: i) the census of the Italian and European material of U. arctos; ii) the analysis of most of the Italian and European fossil and sub-fossil specimens through the use of traditional methodologies (morphological description and biometric analysis); iii) the use of new technologies (axial tomography and digitization of the material through photogrammetry) applied to the analysis of two-dimensional and three-dimensional geometric morphometry.
From the results obtained it has been possible to partially review the systematic position of the species U. etruscus, which would no longer be considered as common ancestor of both the arctoid and speloid lineages in Europe, (Zapfe, 1948; Mazza & Rustioni, 1994). Consequently, the arctoid form entered in Europe during various moments throughout the Quaternary, sharing the territory with U. deningeri first and U. spelaeus later.
Other results show morphological patterns which allow to distinguish these two evolutionary lines, especially in the dental elements and in the brain, although some common features of the skull persist.
Finally, from the study of the specimens from the central-southern Italian area, the first occurrence of U. arctos in Italy at Fontana Ranuccio (Lazio) has been highlighted, and the absence of U. arctos marsicanus features within the fossil record have been reported. Therefore, from the morphological analysis, the split between the two Italian populations should be occurred after the dating of the most recent site studied, the Gran Carro deposit (late Bronze Age / early Iron Age).
50
Gentiluomo, Gina Marie. "The reproducibility of incomplete skulls using freeform modeling plus software." Thesis, 2014. https://hdl.handle.net/2144/15381.
Abstract:
As early as 1883, forensic artists and forensic anthropologists have utilized forensic facial reconstruction in the attempt to identify skulls from decomposed remains. Common knowledge dictates that in order to complete identification from the skull with facial reconstruction, the splanchnocranium (also known as the viscerocranium or facial portion of the skull) needs to still be intact. However, there has been very little research conducted (Colledge 1996; Ismail 2008; Wilkinson and Neave 2001) to determine the minimal amount of intact skull that can be present for a reconstruction to still be possible and accurate. Accordingly, in the present study, the researcher attempted to prove that a skull with significant damage to the splanchnocranium could be repaired and facially reconstructed to bear a likeness to the original skull and face.
Utilizing FreeForm Modeling Plus Software, version 11.0 (Geomagic Solutions - Andover, MA), in conjunction with the Phantom Desktop Haptic Device (Geomagic Solutions - Andover, MA), five CT scans of males between 19 and 40 years old and of varying ethnicities (four Caucasian and one Asian) were digitally altered to present significant skull damage to the splanchnocranium. The hard tissue digital images were repaired using the same software mentioned above and template skulls (i.e., superfluous CT scanned skulls of similar age, sex, and ancestry). The soft tissue digital images were facially reconstructed also utilizing the same software mentioned above and by following basic tissue depth charts/placement rules and guidelines for feature reconstruction.
The reconstructed images were compared to their original CT scans in a side-by-side comparison. Assessors were given a rating scale rubric to fill out that asked them specific questions pertaining to both certain facial features and overall similarity between the original and reconstructed images. Two of the reconstructions each ranked an overall 29% "close resemblance" to their original counterparts, one was ranked an overall 71% "no resemblance" to its original counterpart, and the other three fell somewhere in the middle ("slight" or "approximate") in the rating scale. The results reflected a number of issues related to this project (i.e., the researcher's lack of artistic skill) and to facial reconstruction in general (i.e., tissue depth measurement charts) and showed that while it is not impossible to reconstruct skulls that had been damaged in some capacity, the accuracy of the resulting facial reconstruction is questionable.
Future studies would benefit from using an artist to reconstruct the images rather than someone with little to no experience in the field, a larger sample size consisting of one ancestry to avoid the cross-race effect, a comparison of the original skull to the repaired one utilizing Geomagic Qualify (Geomagic Solutions - Andover, MA) to glean an overall view of the project's accuracy, and utilization of a photo lineup as the method of comparison in addition to a side-by-side comparison to give a more realistic feel to the comparison process.