GoLightly : A GPU Implementation of the Finite-Difference Time-Domain Method

Traditionally, optical circuit design is tested and validated using software which implement numerical modeling techniques such as Beam Propagation, Finite Element Analysis and the Finite-Difference Time-Domain (FDTD) method. FDTD simulations require significant computational power. Existing installations may distribute the computational requirements across large clusters of high-powered servers. This approach entails significant expense in terms of hardware, staffing and software support which may be prohibitive for some research facilities and private-sector engineering firms. The application of modern programmable GPUs to problems in scientific visualization and computation has facilitated faster development cycles for a variety of industry segments including large dataset visualization, aerospace and optical circuit design. GPU-based supercomputers such as National Labs\u27 Summit, co-designed by NVIDIA and IBM, provide dramatically increased compute capability while using less power than CPU-based solutions. The FDTD algorithm maps well to the massively-multithreaded data-parallel nature of GPUs. This thesis explores a GPU-based FDTD implementation and details performance gains, limitations of the GPU approach, optimization techniques and potential future enhancements

Federal Appellate Court Decision in Sequoyah v. TVA, No. 79-1633

Federal Appellate Court Decision in the Case of Ammoneta Sequoyah, Richard Crowe, Gilliam Jackson, Individually and representing other Cherokee Indians similarly situated; the Eastern Band of Cherokee Indians; and the United Ketooah Band of Cherokee Indians, Appellants, v. Tennessee Valley Authority, Appellee. The opinion upholds the lower court\u27s decision to issue summary judgment in favor of the defendants, allowing construction to go forward on the Tellico Dam project. The opinion was written by Pierce Lively, with a dissent by Gilbert S. Merrit Jr. This decision was published in West\u27s Federal Reporter at 620 F.2d 1159 (1980)

Copper complexation during spring phytoplankton blooms in coastal waters

Cupric ion bioassays were conducted throughout the spring phytoplankton bloom season at two stations-one estuarine, dominated by dinoflagellates, the other coastal, dominated by diatoms. Copper-complexing ligands were detected at both locations throughout this period. Ligand concentrations varied between 0.1 and 0.75 μM, with the estuarine concentrations typically 2–4 times higher than coastal values. Ligands from both locations were destroyed by UV-oxidation and had similar conditional stability constants (range 108.3 to 109.2) that were significantly correlated with pH, suggesting that the complexing materials are organic chelators with weak acid functional groups. All measured or calculated parameters (DOC, ligand concentration, total copper concentration, salinity, and pH) remained relatively constant at the coastal station through time. The estuarine station was more dynamic, with DOC, total copper, and ligand concentrations varying 2–4 fold during the study. Although ligand concentrations were significantly different between the two locations, concomitant fluctuations in total dissolved copper and conditional stability constants resulted in a relatively constant estimate of the maximum free cupric ion activity at both stations (near 10–11 M). This suggests that copper toxicity alone was not responsible for the distinctly different estuarine and nearshore phytoplankton assemblages, although sensitive species might have been inhibited at both locations. Major phytoplankton blooms at both sites were not accompanied by changes in DOC or complexation capacity. A significant inverse correlation between ligand concentration and salinity suggests a terrestrial or sedimentary origin for the copper-complexing compounds

Techniques utilized in the simulated altitude testing of a 2D-CD vectoring and reversing nozzle

Simulated altitude testing of a two-dimensional, convergent-divergent, thrust vectoring and reversing exhaust nozzle was accomplished. An important objective of this test was to develop test hardware and techniques to properly operate a vectoring and reversing nozzle within the confines of an altitude test facility. This report presents detailed information on the major test support systems utilized, the operational performance of the systems and the problems encountered, and test equipment improvements recommended for future tests. The most challenging support systems included the multi-axis thrust measurement system, vectored and reverse exhaust gas collection systems, and infrared temperature measurement systems used to evaluate and monitor the nozzle. The feasibility of testing a vectoring and reversing nozzle of this type in an altitude chamber was successfully demonstrated. Supporting systems performed as required. During reverser operation, engine exhaust gases were successfully captured and turned downstream. However, a small amount of exhaust gas spilled out the collector ducts' inlet openings when the reverser was opened more than 60 percent. The spillage did not affect engine or nozzle performance. The three infrared systems which viewed the nozzle through the exhaust collection system worked remarkably well considering the harsh environment

An Assessment of Young Cattle Behaviour and Welfare in a Virtual Fencing System

Virtual fencing is a novel technology which uses a combination of audio and electrical stimuli to contain grazing livestock within a GPS boundary. There are however some concerns around the use of such a technology and its potential effects on the behaviour and welfare of animals. To investigate this, 64 dairy-origin calves were assigned to one of two treatments in a randomised complete block design, with 4 groups of 8 calves per treatment. The two treatments were virtual fencing (VF) and electric fencing (EF). The experimental period lasted 31 days in total, consisting of a 10 day training period and a 21 day grazing period. Welfare and behaviour of the animals was measured using faecal cortisol metabolites, activity pedometers, and behavioural recordings. Virtual fence data denoting the number of audio and electrical stimuli delivered for each animal were also recorded. Results show that there was no significant difference in animal welfare and behaviour between EF and VF in the current study. Additionally, there was no significant difference in daily liveweight gain between treatments. In the VF animals the rate of electric pulses declined after an initial learning period however there was a significant degree of variation in the rate of learning between animals. Virtual fencing could therefore offer an alternative to physical fencing for grazing young cattle without negatively impacting animal behaviour or welfare. The individual animal variation in VF systems however warrants further study

Malware for Macintosh

Technology is a cornerstone of modern society. Unfortunately, it seems that every new piece of technology is accompanied by five computer-security breaches elsewhere. Most people associate hacks with Windows computers. This is a problem because Apple computers, and other non-Windows systems, are also extremely vulnerable to attacks and risk being compromised. Dolos is a piece of malware we developed intended to exploit the macOS Sierra operating system. It provides a framework for running exploits and comes built in with certain control and data exfiltration capabilities. Dolos also helps destroy the misconception of the impenetrable Macintosh computer by showing that Apple computers are also subject to cyber-attacks. The creation of malware like Dolos requires an in-depth knowledge of different security mechanisms and protocols to find the points at which they break. Being aware of those weaknesses allows for the creation of stronger and more resilient systems in the future. We created Dolos to evade anti-virus software by encrypting communication between the attacker and the victim as well as encrypting the malicious code on the victim machine. This allows us to understand the strategies malicious criminals might take so that we may counter their strategies. By designing malware, we are better able to provide security and we begin on the path towards a safer and better world through designing more secure computing systems

Pasture Management in the US Midwest – An Assessment of Current Practices and Future Opportunities

Managed grazing offers significant potential to improve the sustainability of livestock farms in the US Midwest, however the benefits of managed grazing are largely influenced by the management practices employed on farm. The objective of this study was to gain an understanding of current grazing practices on Midwest farms and to identify the knowledge and support needs of graziers. A total of 185 responses were received from a range of different enterprises including dairy, beef, and sheep production. Results show a substantial degree of variation in grazing management practices between respondents and highlights significant scope for improvement on farms particularly in the areas of pasture measurement and budgeting, and grazing infrastructure. Reported benefits of managed grazing included lower environmental impact, better pasture and animal performance, better animal health and welfare, and lower costs. Challenges with managed grazing included time and labor input, maintaining pasture quantity and quality during the grazing season, adverse weather conditions such as excessive rain and drought, and animal health challenges such as heat stress, parasites and in some cases coyotes. The study highlighted opportunities for research and extension providers to better support farmers with information and advice and identified knowledge gaps in areas such as pasture species selection, soil fertility, grazing infrastructure, pasture budgeting, legumes, and pasture measurement. The study successfully gained an insight into graziers in the Midwest, the outputs of which, will be valuable to a number of key stakeholders going forward, including researchers, extension agents, farmers and policy makers

Solar Sail Topology Variations Due to On-Orbit Thermal Effects

The objective of this research was to predict the influence of non-uniform temperature distribution on solar sail topology and the effect of such topology variations on sail performance (thrust, torque). Specifically considered were the thermal effects due to on orbit attitude control maneuvers. Such maneuvers are expected to advance the sail to a position off-normal to the sun by as much as 35 degrees; a solar sail initially deformed by typical pre-tension and solar pressure loads may suffer significant thermally induced strains due to the non-uniform heating caused by these maneuvers. This on-orbit scenario was investigated through development of an automated analytical shape model that iterates many times between sail shape and sail temperature distribution before converging on a final coupled thermal structural affected sail topology. This model utilizes a validated geometrically non-linear finite element model and a thermal radiation subroutine. It was discovered that temperature gradients were deterministic for the off-normal solar angle cases as were thermally induced strains. Performance effects were found to be moderately significant but not as large as initially suspected. A roll torque was detected, and the sail center of pressure shifted by a distance that may influence on-orbit sail control stability

Letters, Lumbees, and Lists

Book 12 of Readings in Bulloch County History is divided into three sections. The first is devoted primarily to correspondence and includes letters from Confederate soldier James Waters, Samuel W. Hodges, and a letter addressed to Rhoda Quinn in Wilkes County. These are followed by notes on the Hodges family by Smith Callaway Banks. The second section of this book is composed of two articles on the Lumbee Indians in Bulloch County, and the third section contains a history of Statesboro High School by Mattie Lively and an early roster of the school’s students and faculty.https://digitalcommons.georgiasouthern.edu/bchs-pubs/1019/thumbnail.jp