Thesis (Ph. D.)--Illinois State University, 2002. / Title from title page screen, viewed February 7, 2006. Dissertation Committee: Beverly S. Rich (chair), Sherry L. Meier, Graham A. Jones, George A. Padavil, Larry D. Stonecipher. Includes bibliographical references (leaves 166-172) and abstract. Also available in print.

One of the challenging design areas of high buildings is the determination of its stability and response to dynamic forces. These factors affect the horizontal deformations and fluctuations that the building will result in. This report examines the demands placed on the stability and deformations of high buildings through a literature study as well as examines these requirements with a reference building built into FEM-Design. The literature study shows that quite a few standards have to be taken into account and used in the design of tall buildings. Regarding limit values, only SS-ISO 10137 specifies maximum values for a building's peak acceleration relative to its own frequency. Limit values for transient deformations are not available. Furthermore, the literature study shows that plenty of studies of human perception and tolerance to movements in buildings have been performed. The movements have been shown to cause physical andmental discomfort if exaggerated, which SS-ISO 10137 bases its limits after. The 75-meter reference building, modeled in FEM-Design, was built to calculate the building's own frequency, transient deflection, and self-weight. The wind loads have been calculated separately and entered into the program. Calculations for the building's peakacceleration have then been calculated and compared to the limitvalues in SS-ISO 10137. The structure of the reference building, consisting of 25-storeys in concrete, met the standard requirements for housing and should be able to be built without the risk of discomfort among the residents. Other inputs were 250 and 200 mm floor and wallthickness in C25 / 30 and VKR pillar in each corner, 200x200x10 mmin quality S355. The plan levels are square 21.8m wide andidentical to all 25 levels.The model-building met the requirements for living space accordingto SS-ISO 10137 with respect to peak acceleration and frequency. However, the calculated horizontal deformations did not have anylimit values to be compared to and were therefore not compared to any restrictions.

The main focus of this thesis is to effectively estimate levels of peak ground acceleration (PGA) during a seismic event for a given site. This will be achieved by applying regression analysis via a mixed model methodology to data collected from previously recorded seismic events collected from the PEER Strong Motion Database using a program written in MATLAB. The basic mixed model combines both fixed and random effect terms. Two models are analyzed and compared based on varying combinations of predictor variables, such as magnitude, distance, shear wave velocity, and site class. While the primary objective of this thesis solely examines the modeling of PGA, the same methodology can be applied in predicting other ground motion intensity parameters such as Peak Ground Velocity (PGV) or the spectral ordinate at a given vibration period.

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

The acceleration of charged particles with ultrafast terahertz electromagnetic radiation could enable new, and improve many of aspects of, accelerator applications. These include providing shorter electron bunches for ultrafast time-resolved pump-probe spectroscopy, enabling complex longitudinal profiles to be imparted onto charged particle bunches and significantly improving the ability to synchronise an accelerator to an external laser. In this thesis I present investigations into terahertz radiation sources that enabled the generation of terahertz radiation with attractive properties for accelerator based applications. Specific attention has been paid to temporally tunable sources that generate strong longitudinally polarised electric field components as these enable a free-space co-linear interaction geometry to be implemented. A simulation describing the propagation of radiation from such sources has been developed. Terahertz sources have been designed and the radiation generated characterised via electro optic detection. These include a radially biased photoconductive antenna (PCA) based source of which the longitudinally polarised terahertz electric field component was found to have an amplitude of 2.22 kVcm-1 as well as a near-single cycle temporal profile. This radially biased PCA was used in conjunction with the Accelerators and Lasers in Combined Experiments (ALICE) energy recovery linear accelerator at the Daresbury Laboratory in an electron acceleration experiment. To enable higher longitudinally polarised terahertz electric field strengths to be obtained, as well as the ability to temporally tune the terahertz radiation, generation within non-linear optical crystals was investigated. Magnesium-oxide doped stoichiometric lithium niobate (MgO:SLN) was investigated as a possible candidate due to its high non-linear susceptibility tensor and reported ability to impose temporal tuning directly from the pump laser beam. A scheme consisting of two MgO:SLN crystals each generating a separate linear polarised terahertz pulse which were then combined via a lens was designed and built. Electro optic detection techniques were used to characterise the radiation generated from this source. Peak terahertz electric fields amplitudes of 11.6 kVcm-1 and 47 kVcm-1 were measured for both the longitudinally and transversely polarised field components respectively. Temporal profiles measured from both the longitudinally and transversely polarised electric field components showed electric field periods of approximately 300 fs. This method of generating terahertz radiation employed a pulse-front tilt technique. Allowing for the same scaling as recently reported in the literature for MgO:SLN generation techniques, which will in principle allow this method to scale to longitudinally polarised terahertz electric field profiles in excess of 1 MVcm-1.

Three key enhancements were made to a semiempirical molecular orbital program to develop a fast, accurate method of calculating chemical properties of large (> 1000 atom) molecular systems, through the use of quantum theory. In this thesis the key enhancements are presented which are: the implementation of a divide-and-conquer approach to a self-consistent field procedure, in an effort to improve capability; the use of the novel technology, GPU technology, to parallelize the divide-and-conquer self-consistent field procedure, in an effort to improve the speed; the implementation of a newly developed semiempirical model, the Polarized Molecular Orbital Model, in an effort to improve the accuracy. The development of a divide-and-conquer approach to the SCF (DC-SCF) procedure (enhancement 1) was carried out using saturated hydrocarbon chains whereby the saturated hydrocarbon chain is partitioned into small overlapping subsystems and the Roothaan equations solved for each subsystem. An investigation was carried out to find the optimal partitioning scheme for saturated hydrocarbon chains in order to minimize the loss of energy experienced from neglecting some of the interactions in the system whilst maintaining near linear scaling with system size. The DC-SCF procedure was shown to be accurate to 10-3 kcal mol-1 per atom whilst calculating the SCF-energy nearly 6 times faster than using the standard SCF procedure, for a 698-atom system. The development of a parallel DC-SCF procedure and Cartesian forces calculation for use on a GPU (enhancement 2), resulted in a hybrid CPU/GPU DC-SCF implementation that calculated the energy of a 1997-atom saturated hydrocarbon chain 21 times faster than the standard serial SCF implementation and a accelerated Cartesian forces calculation that performed 7 times faster for a saturated hydrocarbon chain of 1205-atoms, when accelerated using an NVidia Tesla C2050 GPU. The hybrid CPU/GPU algorithm made use of commercially accelerated linear algebra libraries, CULA and CUBLAS. A comparison was made between CULA’s accelerated eigensolver routine and the accelerated DC-eigensolver (developed in this research) and it was found that for saturated hydrocarbon chains of > 350 atoms, the accelerated DC-eigensolver performed around twice as fast as the accelerated CULA eigensolver. The implementation of the Polarized Molecular Orbital model (enhancement 3) was validated against published isomerization energies and benchmarked against the non-nitrogen containing complexes in the S66 database. The benchmark complexes were categorized according to dominant intermolecular interactions namely, hydrogen bonding, dispersion interactions and mixed interactions. After assessment it was found that the PMO model predicts interaction energies of complexes with a mixture of dispersive and electrostatic interactions to the highest accuracy (0.69 kcal mol-1 with respect to CCSD(T)/CBS). The dispersion correction within the PMO model was found to ‘overcorrect’ the dispersive contribution for most complexes tested. The outcome of this research is a semiempirical molecular orbital program that calculates the energy of a closed-shell saturated hydrocarbon chain of ~2000 atoms in under 4 minutes instead of 1.5 hours when using a PM3-Hamiltonian and can calculate interaction energies of systems exhibiting a mixture of electrostatic and dispersive interactions to an accuracy of within 1 kcal mol-1 (relative to high-level quantum methods). To demonstrate a suitable application for the enhanced SE-MO program, interaction energies of a series of PAHs with water, phenol and methanol have been investigated. The resultant program is suitable for use in calculating the energy and forces of large material and (in future) biological systems by a fast and accurate method that would be impractical or impossible to do without these enhancements.

The varied impact parameters that characterize an impact to the head have shown to influence the resulting type and severity of outcome injury, both in terms of the dynamic response, and the corresponding deformation of neural tissue. Therefore, when determining head injury risks through event reconstruction, it is important to understand how individual impact characteristics influence these responses. The effect of inbound mass had not yet been documented in the literature. The purpose of this study was to determine the effects of inbound mass on the dynamic impact response and brain tissue deformation. A 50th percentile Hybrid III adult male head form was impacted using a simple pendulum system. Impacts to a centric and a non-centric impact location were performed with six varied inbound masses at a velocity of 4.0 m/s. The peak linear and peak angular accelerations were measured. A finite element model, (UCDBTM) was used to determine brain deformation, namely peak maximum principal strain and peak von Mises stress. Inbound mass produced significant differences for peak linear acceleration for centric (F(5, 24) = 217.55, p=.0005) and non-centric (F(5, 24) = 161.98, p=.0005), and for peak angular acceleration for centric (F(5, 24) = 52.51, p=.0005) and non-centric (F(5, 24) = 4.18, p=.007) impact locations. A change in inbound mass also had a significant effect on peak maximum principal strain for centric (F(5, 24) = 11.04, p=.0005) and non-centric (F(5, 24) = 5.87, p =.001), and for peak von Mises stress for centric (F(5, 24) = 24.01, p=.0005) and non-centric (F(5, 24) = 4.62, p=.004) impact locations. These results indicate the inbound mass of an impact should be of consideration when determining risks and prevention to head and brain injury.

Denna studie undersöker vilket stöd lärare får från rektor och huvudman för att kunna undervisa särskilt begåvade elever i matematik. Den granskar även hur lärare bedriver undervisningen av dessa elever och vilket stöd lärare anser sig sakna från rektor och huvudman för att kunna bedriva undervisningen för särskilt begåvade elever inom matematik. Detta har studerats med en enkät som rektor fick besvara samt intervjuer med lärare. Frågorna baserades på en taxonomi designad för att utveckla och förbättra matematikundervisningen, samt generella undervisningsstrategier för de särskilt begåvade. Fem rektorer och fem lärare, utspridda över fem skolor i norra Sverige deltog i studien. Resultatet visade att lärare inte får särskilt mycket stöd för att undervisa särskilt begåvade elever i matematik i de flesta fall på de utvalda skolorna samt att lärare använde sig av två metoder för att undervisa dessa elever: Acceleration och berikning.

In this work, MEMS inertial switches intended to be triggered at multiple acceleration thresholds in two directions were implemented and proven effective. The switches consume virtually no power in their open switching state. Multiple acceleration thresholds can be beneficial in triggering different actions for different acceleration events. Low power consumption can aid in their use for portable applications such as in cycling helmets. The developed designs rely mainly on a suspended shuttle mass, which is used to implement one of two methods of actuation. The first relies on simple contact between the moving shuttle mass and a flexible electrode. In the second, the pull-in instability is induced by applying a voltage between a cantilever and an electrode, and then having the shuttle mass force the cantilever moving towards the electrode as it moves under the applied acceleration. Ten designs varying in their actuation method, suspension design, intended acceleration thresholds, and dimensions were modeled using a finite element model, fabricated, through the SOIMUMPs process, and then electrically and mechanically tested. Mechanical testing has been conducted using Drop-table tests and mechanical shakers. The simple contact devices were proven effective through shock test results showing triggering at two acceleration thresholds in two directions. Initial results also were promising for the pull-in based devices showing switching by moving their shuttle mass with a probe while applying appropriate voltage and observing under a microscope.

The purpose of this study was to investigate the suitability of using the OpenGL and OpenCL graphics application programming interfaces (APIs), to increase the speed at which 2D vector geographic information could be rendered. The research focused on rendering APIs available to the Windows operating system. In order to determine the suitability of OpenGL for efficiently rendering geographic data, this dissertation looked at how software and hardware based rendering performed. The results were then compared to that of the different rendering APIs. In order to collect the data necessary to achieve this; an in-depth study of geographic information systems (GIS), geographic coordinate systems, OpenGL and OpenCL was conducted. A simplistic 2D geographic rendering engine was then constructed using a number of graphic APIs which included GDI, GDI+, DirectX, OpenGL and the Direct2D API. The purpose of the developed rendering engine was to provide a tool on which to perform a number of rendering experiments. A large dataset was then rendered via each of the implementations. The processing times as well as image quality were recorded and analysed. This research investigated the potential issues such as acquiring data to be rendered for the API as fast as possible. This was needed to ensure saturation at the API level. Other aspects such as difficulty of implementation as well as implementation differences were examined. Additionally, leveraging the OpenCL API in conjunction with the TopoJSON storage format as a means of data compression was investigated. Compression is beneficial in that to get optimal rendering performance from OpenGL, the graphic data to be rendered needs to reside in the graphics processing unit (GPU) memory bank. More data in GPU memory in turn theoretically provides faster rendering times. The aim was to utilise the extra processing power of the GPU to decode the data and then pass it to the OpenGL API for rendering and display. This was achievable via OpenGL/OpenCL context sharing. The results of the research showed that on average, the OpenGL API provided a significant speedup of between nine and fifteen times that of GDI and GDI+. This means a faster and more performant rendering engine could be built with OpenGL at its core. Additional experiments show that the OpenGL API performed faster than GDI and GDI+ even when a dedicated graphics device is not present. A challenge early in the experiments was related to the supply of data to the graphic API. Disk access is orders of magnitude slower than the rest of the computer system. As such, in order to saturate the different graphics APIs, data had to be loaded into main memory. Using the TopoJSON storage format yielded decent data compression allowing a larger amount of data to be stored on the GPU. However, in an initial experiment, it took longer to process the TopoJSON file into a flat structure that could be utilised by OpenGL than to simply use the actual created objects, process them on the central processing unit (CPU) and then upload them directly to OpenGL. It is left as future work to develop a more efficient algorithm for converting from TopoJSON format to a format that OpenCL can utilise. / Dissertation (MSc)--University of Pretoria, 2014. / tm2015 / Geography, Geoinformatics and Meteorology / MSc / Unrestricted