ABSTRACT Effect of Warm-Up Activity on Vertical Ground Reaction Forces in Basketball Players During Drop Jump Landings Jacob Hinkel-Lipsker Purpose: The purpose of this study was to examine the effect of certain warm-up activities on vertical ground reaction forces (GRFv) during a drop jump landing. Methods: Eight women and twelve men (mean age 22.6 ± 1.82 years) completed three warm-up activities on three separate days in a counterbalanced order: a passive stretching warm-up, a dynamic warm-up, and a no warm-up control. After completing each activity, participants were asked to perform eight drop jump landings on a force platform. GRFv data was sampled at 1000 Hz during each landing, and the variables analyzed were: peak forefoot and rearfoot magnitude, forefoot and rearfoot rate of loading, and impulse. Results: The dynamic warm-up had significantly greater values (p < 0.05) for forefoot peak magnitude, rearfoot peak magnitude, and forefoot rate of loading compared to the passive stretching and control conditions. Also, there were no significant differences among all activities for rearfoot rate of loading and impulse. Conclusions: The significantly greater values for forefoot peak magnitude, rearfoot peak magnitude, and forefoot rate of loading that the dynamic warm-up produced indicates that this activity may be effective in increasing muscular stiffness in the lower limbs. The failure of the passive stretching warm-up to reach significance indicates that this activity may not be effective in decreasing lower extremity muscular stiffness.

Traditional autonomy among robotic and other artificial agents was accomplished via automated planning methods that found a viable sequence of actions, which, if executed by an agent, would result in the successful completion of the given task(s). However, many tasks that we would like robotic agents to perform involve goals that are complex, poorly-defined, or hard to specify. Furthermore, significant amounts of data or computation are required for agents to reach reasonable performance. As a result, autonomous systems still rely on human operators to play a supervisory role to ensure that robotic operations are completed quickly and successfully. The presented work aims to improve the traditional methods of robot autonomy by developing an intuitive means for(human operators to adapt/mold the behaviors and decision making of autonomous agents) autonomous agents to leverage the flexibility and expertise of human end users. Specifically, this work shows the results of three machine learning-based approaches for modifying and extending established robot navigation behaviors and skills through human demonstration. Our first project combines Imitation learning with classical navigation software to achieve long-horizon planning and navigation that follows navigation rules specified by a human user. We show that this method can adapt a robot's navigation behavior to become more like that of a human demonstrator. Moreover, for a minimal amount of demonstration data, we find that this approach outperforms recent baselines in both navigation success rate and trajectory similarity to the demonstrator. In the second project, we introduce a method of communicating complex skills over a short-horizon task. Specifically, we explore using imitation learning to teach a robot the complex skill needed to safely navigate through negative obstacles in simulation. We find that this proposed method could imitate complex navigation behaviors and generalize to novel environments in simulation with minimal demonstration. Furthermore, we find that this method compares favorably to a classical motion planning algorithm which was modified to assign traversal cost based on the terrain slope local to the robot's current pose. Finally, we demonstrate a practical implementation of the second approach in a real-world environment. We show that the proposed method results in a policy that can generalize across differently shaped obstacles and across simulation and reality. Moreover, we show that the proposed method still outperforms the classical motion planning algorithm when tasked to navigate negative obstacles in the real world. / Doctor of Philosophy / With the rapid advancement of computing power and growing technical literacy of the general public, the tasks that robots should be able to accomplish have multiplied. Robots can, however, be limited by the human ability to effectively convey how tasks should be performed. For example, autonomous robot navigation to a specified path planning software suite that generates feasible and obstacle-free trajectories through a cluttered environment. While these modules can be modified to meet task-specific constraints and user preferences, current modification procedures require substantial effort on the part of an expert roboticist with a great deal of technical training. The desired tasks and skills are difficult to effectively convey in a machine legible format. These tasks often require technical expertise in multiple mechatronic disciplines and hours of hand tuning that the typical end user does not have. In this dissertation, we examine methods that directly leverage human users to teach robots how to perform tasks that are generally difficult to specify pragmatically. We focus on methods that allow human users to extend established robot navigation behaviors and skills by demonstrating their own preferred approaches. We evaluate the performances of our proposed approaches in terms of navigation success rate, adherence to the demonstrated behavior, and their ability to apply what they have learned to novel environments. Moreover, we showed that our approaches compare favorably to recent machine learning-based approaches to autonomous navigation, and classical navigation techniques with respect to these metrics.

The flexibility of the floor slabs is quite often ignored in the seismic analysis of structures. In general, the rigid behavior assumption is appropriate to describe the in-plane response of floors. For seismic excitations with vertical components, however, the flexibility of the floor slabs in the out-of-plane direction may play a significant role and it can result in an increase in the seismic response. The simplified procedures used in the current practice to include the floor flexibility can lead to highly conservative estimates of the slab and supported equipment response. To include floor flexibility, a detailed finite element model of the structure can be constructed, but this procedure leads to a system with large degrees of freedom the solution of which can be time consuming and impractical. In this study, a new dynamic condensation approach is developed and proposed to reduce the size of the problem and to calculate the seismic response of structures with flexible floor slabs. Unlike other currently available dynamic condensation techniques, this approach is applicable to classically as well as nonclassically damped structures. The approach is also applicable to structures divided into substructures. The approach can be used to calculate as many lower eigenproperties as one desires. The remaining higher modal properties can also be obtained, if desired, by solving a complementary eigenvalue problem associated with the higher modes. The accuracy of the calculated eigenproperties can be increased to any desired level by iteratively solving a condensed and improved eigenvalue problem. Almost exact eigenproperties can be obtained in just a few iterative cycles. Numerical examples demonstrating the effectiveness of the proposed approach for calculating eigenproperties are presented. To calculate the seismic response, first the proposed dynamic condensation approach is utilized to calculate the eigenproperties of the structure accurately. These eigenproperties are then used to calculate the seismic response for random inputs such as a spectral density function or inputs defined in terms of design response spectra. Herein, this method is used to investigate the influence of the out-of-plane flexibility of the floor slabs on the response of primary and secondary systems subjected to vertical ground motions. The calculated results clearly show that inclusion of the floor flexibility in the analytical model increases the design response significantly, especially when computing acceleration floor response spectra. This has special relevance for secondary systems and equipment the design of which are based on the floor response spectra. The accuracy of the results predicted by two of the most popular methods used in practice to consider the floor flexibility effects, namely the cascade approach and the modified lumped mass method, is also investigated. The numerical results show that the cascade approach overestimates the seismic response, whereas the modified lumped mass method underestimates the response. Both methods can introduce significant errors in the response especially when computing accelerations and floor response spectra. For seismic design of secondary systems supported on flexible slabs, the use of the proposed condensation approach is thus advocated. / Ph. D.

Next generation aircraft design focuses on highly integrated airframe/engine architectures that exploit advantages in system level efficiency and performance. One such design concept incorporates boundary layer ingestion which locates the turbofan engine inlet near enough to the lifting surface of the aircraft skin that the boundary layer is ingested and reenergized. This process reduces overall aircraft drag and associated required thrust, resulting in fuel savings and decreased emissions; however, boundary layer ingestion also creates unique challenges for the turbofan engines operating in less than optimal inlet flow conditions. The engine inlet flow profiles predicted from boundary layer ingesting aircraft architectures contain complex distortions that affect the engine operability, durability, efficiency, and performance. One component of these complex distortion profiles is off-axial secondary flow, commonly referred to as swirl. As a means to investigate the interactions of swirl distortion with turbofan engines, an experiment was designed to measure distorted flow profiles in an operating turbofan research engine. Three-dimensional flow properties were measured at discrete planes immediately upstream and immediately downstream of the fan rotor, isolating the component for analysis. Constant speed tests were conducted under clean and distorted test conditions. For clean tests, a straight cylindrical inlet duct was attached to the fan case; for distorted tests, a StreamVane swirl distortion generator was inserted into the inlet duct. The StreamVane was designed to induce a swirl distortion matching results of computation fluid dynamics models of a conceptual blended wing body aircraft at a plane upstream of the fan. The swirl distortion was then free to develop naturally within the inlet duct before being ingested by the engine. Results from the investigation revealed that the generated swirl profile developed, mixed, and dissipated in the inlet duct upstream of the fan. Measurements immediately upstream of the fan rotor leading edge revealed 50% reduction in measured flow angle magnitudes along with evidence of fanwise vortex convection when compared to the StreamVane design profile. The upstream measurements also indicated large amounts of secondary flow entered the fan rotor. Measurements immediately downstream of the fan rotor trailing edge demonstrated that the fan processed the distortion and further reduced the intensity of the swirl; however, non-uniform secondary flow persisted at this plane. The downstream measurements confirmed that off-design conditions entered the fan exit guide vanes, likely contributing to cascading performance deficiencies in downstream components and reducing the performance of the propulsor system. / Master of Science

In the Israel-Palestinian conflict, peace conferences and agreements come and go. Public and political discourse about the conflict waxes and wanes. Meanwhile, new and expanded Israeli settlements in the West Bank continue to grow unabated. The history of settlements in the West Bank began with the conclusion of the 1967 war during which Israel successfully took over the West Bank Palestinian territory. According to international law, building settlements in the West Bank is illegal. Israel contends that such settlements are not illegal because the West Bank is disputed territory, not occupied territory. The possibility of a Palestinian state is likely preempted because Israeli settlements comprise close to 40% of the landmass in the occupied territory. The occupation of the West Bank (and Gaza) and the continuing growth of settlements are a perversion of classic political realism because these actions create an increased threat to the long-term national security of Israel and to the safety of the global Jewish community. / Master of Arts

This paper presents results of a comprehensive investigation undertaken to quantify the efficiency of using reinforcement layers in order to enhance the bearing capacity of soils that are characterised by the existence of localised soft pockets. Small-scale model experiments using two dimensional tank were conducted with beds created from well graded sand with mean particle size of 300 μm but prepared with different dry densities. A relatively softer material was embedded at predetermined locations within the sand beds so as to represent localised soft pockets. Various arrangements of soil reinforcement were tested and compared against comparable tests but without reinforcement. In total 42 tests were carried out in order to study the effect of the width and depth of the soft pocket, the depth of one reinforcing layer and the length and number of reinforcing layers on the soil bearing capacity. The results show clearly that the ultimate bearing capacity reduces by up to 70% due to the presence of a soft pocket. It was also noted that the proximity of the soft pocket also influenced the bearing capacity. Reinforcing the soil with a single layer or increasing the length of reinforcement is not as effective as was anticipated based on previous studies. However, bearing capacity increased significantly (up to 4 times) to that of unreinforced sand when four layers of reinforcement were embedded. The results suggest that rupture of the bottom reinforcement layer is imminent in heavily reinforced sand beds overlying soft pockets and therefore its tensile strength is critical for successful reinforcement.

Polyurethane resin injection is a treatment being considered as a replacement for traditional methods of ground improvement. It has been used to re-level foundations and concrete slabs that have settled over time. Additional claimed benefits of the treatment have been noted recently, including improved factors of safety against soil liquefaction and reduced earthquake-induced settlements. To investigate the capability of the polyurethane resin injection treatment to mitigate liquefaction, two full-scale blast liquefaction tests were performed; one test was conducted in an improved panel (IP), an 8 m circular area treated with the polyurethane resin in a 1.2 m triangular grid from a depth of 1 to 6 m, and another test in an untreated 8 m circular area, the natural panel (NP). Each blast test was severe enough to produce liquefaction (ru ≈1.0) in the respective panel, with blast-induced settlements in the range of 70 to 80 mm. Despite similar levels of ground-surface settlement in the IP and NP, settlement within the top 6 m of the IP was about half that of the NP. A CPT-based predicted settlement for each panel was employed using the Zhang et al. (2002) methodology. Good correlation was found between the observed settlements and predicted settlements in both panels. Differential settlements across the panels were calculated based on ground-based lidar surveys, with a reduction of 42 to 49% between the IP and NP. The measured total and differential settlements following resin injection were at the bottom of the range observed in blast tests on a variety of shallow ground improvement methods conducted by the New Zealand Earthquake Commission in 2013. The persistence of the polyurethane resin injection ground improvement three years following its installation was indicated by the lasting increase of fundamental in situ test parameters. The results of the study indicate that resin injection is a viable method of ground improvement to reduce liquefaction-induced settlements by creating a stiffer surficial crust.

Unmanned ground vehicles (UGV) are being explored for use in military domains. Military UGVs operate in complex off-road environments. Vehicle mobility forecasting plays an important role in understanding how and where a vehicle can operate. Traditional mobility forecasting has been done using an analytical model known as the NATO Reference Mobility Model (NRMM). There has been a push to extend the forecasting capabilities of NRMM by integrating more simulation methods. Simulation enables the repeated testing of UGVs in scenarios that would be difficult or dangerous to study in real world testing. To accurately capture UGV performance in simulation, the operating environment must be accurately modeled. Current widely used methods for generating forested virtual environments rely on random methods. These methods result in forests that can appear to be realistic when visually inspected but lack the appropriate distribution of different sizes of vegetation. The size and distribution of vegetation plays a major role in the ability of a vehicle to operate in a forested environment. Therefore, there is a need for alternative forest generation algorithms that generate more realistic virtual forests. To address this, a novel environment generation model based on forest ecology was implemented. This model accurately captures vegetation growth, disbursement, and competition. Simulated UGV self-driving performance for scenes generated using the ecological model was compared to performance for scenes generated using a widely adopted random model. Resulting speeds across each scene were averaged to predict a speed made good (SMG). Vehicle SMG predictions were made in NRMM using scene descriptions matching each of the random and ecological scenes. Using a continuous vegetation override function in simulation, SMG predictions for both methods were similar to the results of NRMM. However, the predicted speeds for scenes generated with the ecological model were different from the predicted speeds for scenes generated with the random model. When examining the distribution and frequency of different sizes of trees, ecological scenes more closely match the distribution and frequency of trees that are expected for real forested environments suggesting that predictions for speed in ecological scenes better represent potential speeds for real environments.

Hematological comparisons were made on the Uinta ground squirrel (Citellus armatus) trapped at different altitudes and during vari ou s stages of seasonal activity in 1965 and 1966. Hematological variation due to sex, sexual activity and body weight were also analyzed. Ground squirrels were secured from the Mt. Timpanogos area near Provo, Utah County, Utah. Erythrocyte count, hematocrit, total blood hemoglobin, mean erythrocyte volume, mean erythrocyte hemoglobin and reticulocyte counts were measured using standard procedures; banding patterns of hemoglobin and serum proteins wer e determined by means of electrophoresis with polyacetate strips.

The purpose of this investigation was to study the weight changes of selected internal organs to determine possible physiological variation occurring at six different altitudes ranging from 5,800 to 8,500 feetand during the summer season. This report was limited to the study of changes in the adrenal glands, kidneys, testes, heart and intestines. Electrocardiogram, heart and respiration rates were investigated also. These changes were statistically analyzed to determine possible seasonal differences along with any significant changes occurring at different elevations. The results of the study should in part overcome the lack of current experimental data for Citellus armatus.