Rendering of natural scenes has interested the scientific community for a long time due to its numerous applications. The targeted goal is to create images that are similar to what a viewer can see in real life with his/her eyes. The main obstacle is complexity: nature scenes from real life contain a huge number of small details that are hard to model, take a lot of time to render and require a huge amount of memory unavailable in current computers. This complexity mainly comes from geometry and lighting. The goal of our research is to overcome this complexity and to achieve real-time rendering of nature scenes while providing visually convincing dynamic global illumination. Our work focuses on grass and trees as they are commonly visible in everyday life. We handle geometry and lighting complexities for grass to render millions of grass blades interactively with dynamic lighting. As for lighting complexity, we address real-time rendering of trees by proposing a lighting model that handles indirect lighting. Our work makes extensive use of the current generation of Graphics Processing Units (GPUs) to meet the real-time requirement and to leave the CPU free to carry out other tasks.

This study evaluates soil properties that impact the effectiveness of soil aquifer treatment (SAT) as a polishing step to the remove two classes of ECs from wastewater effluent: pharmaceuticals and personal care products (PPCPs), and engineering nanomaterials (ENMs). In recent years, it has been determined that elevated levels of emerging contaminants (ECs) are being released into the environment with wastewater effluent. ECs are proven to cause adverse environmental and health effects as a result of long-term exposure. It is important to evaluate sustainable solutions to improve the current methods of wastewater treatment to address these ECs. Soil aquifer treatment (SAT) is a sustainable, cost effect treatment alternative to advanced treatment at a wastewater treatment plant. SAT replenishes local groundwater supplies while allowing for indirect potable reuse, if contaminants of concern such as ECs can be effectively removed from the water. Since wastewater effluent can contain a variety of contaminants with myriad physical and chemical properties, understanding the potential of the aquifer itself to provide EC removal is a key step in establishing SAT as a viable treatment alternative. Peer-reviewed research studies were analyzed to determine the soil properties that affect the fate and transport of ECs in the aquifer environment. The data was complied to produce recommendations for an effective SAT site. Physical and chemical properties of the soil facilitate contaminant removal as the groundwater flows through the aquifer. This study determined that removal of ECs from effluent had a correlation with (1) high clay content, (2) small Darcy Velocity, (3) high soil organic matter content, and (4) low sand content. Based on the 6 peer-reviewed research studies reviewed, the removal of nanomaterials is affected by clay content and sand content, but not soil organic matter content. Conversely, the removal of PPCPs is affected by clay content and soil organic mater content, but not sand content. It can be concluded that two different removal mechanisms facilitate the removal of nanomaterials versus PPCPs; physical removal for nanomaterials and chemical removal (sorption) for PPCPs. Clay facilitates the removal of both contaminants. The small soil diameter of clay forms smaller pores in the soil media. This causes increased pore straining, while also restricting the flow through the soil, which increases the contact time between the soil particle and the ECs. Additionally, clay has a large surface area, which increases surface interactions, such as sorption, of the EC to the surface of the clay particle.

Humans have caused grave ecological and economic damage worldwide through the introduction of invasive species. Understanding the factors that influence community susceptibility to invasion are important for controlling further spread of invasive species. Predators have been found to provide biotic resistance to invasion in both terrestrial and marine systems. However, predators can also have the opposite effect, and facilitate invasion. Therefore, recovery or expansion of native predators could facilitate the spread of invasive species. Needles et al. (2015) demonstrated that the threatened southern sea otter (Enhydra lutris nereis) facilitated the invasion of an exotic bryozoan, Watersipora subatra. However, the underlying mechanism was not fully understood. We tested the hypothesis that sea otter predation on Romaleon antennarium crabs indirectly facilitated the abundance of W. subatra. To do this, we collected weekly data on sea otter foraging and quantified the abundance of crabs in the sea otter diet. We also conducted a caging experiment, where we experimentally manipulated crab densities and limited otter access using exclusion cages on pier pilings in Morro Bay, CA. We used photoQuad image processing software to calculate the abundance of W. subatra on PVC panels within each treatment group. We found that crabs were the second most abundant prey item in Morro Bay, comprising 25.1% of the otter diet. Through the caging experiment, we found that W. subatra abundance significantly increased as crab densities decreased. Our results indicated that sea otters indirectly facilitated the invasion of W. subatra by reducing R. antennarium crab densities and sizes. Removal of crabs may release W. subatra from the disturbance caused by crab foraging behavior. Understanding the impacts of top predators in invaded ecosystems has important management implications, as recovery of predator populations could unintentionally benefit some non-native species. Therefore, management should focus first on prevention and second on early detection and eradication of invasive species likely to benefit from predator recovery.

<p>Current indirect optimal control problem (IOCP) solvers, like beluga or PINs, use symbolic math to derive the necessary conditions to solve the IOCP. This limits the capability of IOCP solvers by only admitting symbolically representable functions. The purpose of this thesis is to present a framework that extends those solvers to derive the necessary conditions of an IOCP with fully numeric methods. With fully numeric methods, additional types of functions, including conditional logic functions and look-up tables can now be easily used in the IOCP solver.</p> <p><br></p> <p>This aim was achieved by implementing algorithmic differentiation (AD) as a method to derive the IOCP necessary conditions into a new solver called Giuseppe. The Brachistochrone problem was derived analytically and compared Giuseppe to validate the automatic derivation of necessary conditions. Two additional problems are compared and extended using this new solver. The first problem, the maximum cross-range problem, demonstrates a trajectory can be optimized indirectly while utilizing a conditional density function that switches as a function of height according to the 1976 U.S. atmosphere model. The second problem, the minimum time to climb problem, demonstrates a trajectory can be optimized indirectly while utilizing 6 interpolated look up tables for lift, drag, thrust, and atmospheric conditions. The AD method yields the exact same precision as the symbolic methods, rather than introducing numeric error as finite difference derivatives would with the benefit of admitting conditional switching functions and look-up tables. </p>

Elections are a democratic process intended to create peaceful and legitimate transfers of power. However, since the second and third waves of democratisation, policymakers and researchers have observed that electoral processes are transformed into arenas for political gain through violence. To counteract this destructive phenomenon, research needs to uncover why, where, how, by or on whom electoral violence occurs. A common denominator for countries that face election violence is colonial legacies. Therefore, this study attempts to explain the occurrence of electoral violence in postcolonial states through variance in colonial governance type, as they produce diverging societal aspects that can create conditions for electoral violence. The study applies an established theoretical framework from postcolonial theory on a regression testing the effect of indirect colonial rule, contra direct colonial rule on the occurrence of electoral violence. The regression results support the theory until colonial rulers and geographical location are controlled for, ultimately going against the proposed theory. However, the multivariate regression models are statistically insignificant, which makes the result of the study inconclusive. Robustness tests support the inconclusive result of the primary model and indicate the importance of segregating electoral violence based on perpetrator.

While descriptive assessment outcomes show limited correspondence with experimental analysis outcomes, they are still often used in the treatment of problem behavior. The most effective way of treating problem behavior is by manipulating its controlling variables; however, if descriptive analyses are not depicting accurate environment-behavior relations, then treatments based off of descriptive analysis results have a higher chance of failing. The current study looks to replicate and extend the literature on utility descriptive assessments by analyzing three different data analysis methods. Three children with a diagnosis of autism were exposed to two types of experimental analyses. Following experimental analyses, descriptive assessments were completed and analyzed to determine correlations between the behavior and environmental events. The results from the three investigated data analysis methods were then compared to the outcomes of the experimental analyses.

No description available.

The belief that intentions are hidden away in the minds of individuals has been circulating for many years. Theories of indirect perception, such as the Theory of Mind, have since been developed to help explain this phenomenon. Conversely, research in the field of human kinematics and event perception have also given rise to theories of direct perception. The purpose of the study was to determine if intentionality can be directly perceived rather than requiring inferential processes. Prior research regarding kinematics of cooperative and competitive movements have pointed toward direct perception, demonstrating participants can accurately judge a movement as cooperative or competitive by simply observing point-light displays of the isolated arm movements. Considering competitive movements are often performed faster than cooperative movements, speed was perturbed for the purpose of this study to determine if participants are relying on cues or if they can indeed perceive a unique kinematic pattern that corresponds to intentionality. Judging the clips correctly despite perturbation would suggest perception is direct. Additionally, we hypothesized judgments accuracy would be higher in the presence of two actors pointing to the use of interpersonal affordances. Twenty-eight participants from the University of Central Florida were asked to judge 40 clips presented in random order including: normal or perturbed competitive actions with one or two actors; normal or perturbed cooperative actions with one or two actors. Percent correct and reaction time data were analyzed on SPSS using a repeated measures ANOVA. Results rejected the hypothesis that social perception is direct and supported indirect perception, indicating participants relied on cues to make judgments, and provided potential support for the interpersonal affordance hypothesis.

An evaluation of aged hot-mix asphalt (HMA) pavements was accomplished to develop a method for improving the prediction of remaining fatigue life of aged HMA surfaces. This is important for both planning Department of Defense airfield maintenance funds and for predicting the performance of operating surfaces in the theater of operation. This study involved the evaluation of HMA at several military airfields. After field inspections and field testing, slab samples were carried to the U.S. Army Engineer Research and Development Center for laboratory testing. Laboratory testing included the determination of mixture and binder properties, indirect tensile strength tests on cored specimens, and beam fatigue tests. The results from this study were used to develop improved fatigue performance predictions for field-aged HMA pavements.

No description available.