617 research outputs found
Lagrangian Coherent Structures: A Climatological Look
A relatively new area at the crossroads of fluid and nonlinear dynamics are objects known as Lagrangian Coherent Structures (LCSs). LCSs are mathematically classified to differentiate parts of fluid flows. They, themselves, are the most influential parts of fluids. These objects have the most influence on the fluids around them and they allow for a sense of hierarchy in an otherwise busy environment of endless variables and trajectories. While all particles of fluids have the same dynamics on an individual basis, areas of fluid are not created equal and to be able to detect which parts will be the most important to look at allows for easier, but just as accurate, prediction of fluid movement. Recent applications include cleanup operations during the BP Deepwater Horizon oil spill, pollutant transfer in oceanic basins, and the analysis of polar storm activity. This thesis explores LCSs from the discrete mathematics to the future climatological impacts using virtual fluid simulations and LCS detection tools to facilitate analysis as well as diving into a case study with real and unapproximated oceanic data in the days following the Fukushima Daiichi nuclear power plant disaster
Multi-aperture foveated imaging
Foveated imaging, such as that evolved by biological systems to provide high angular resolution with a reduced space–bandwidth product, also offers advantages for man-made task-specific imaging. Foveated imaging systems using exclusively optical distortion are complex, bulky, and high cost, however. We demonstrate foveated imaging using a planar array of identical cameras combined with a prism array and superresolution reconstruction of a mosaicked image with a foveal variation in angular resolution of 5.9:1 and a quadrupling of the field of view. The combination of low-cost, mass-produced cameras and optics with computational image recovery offers enhanced capability of achieving large foveal ratios from compact, low-cost imaging systems
A complete record from colonization to extinction reveals density dependence and the importance of winter conditions for a population of the silvery blue, Glaucopsyche lygdamus.
Butterflies in the family Lycaenidac are often the focus of conservation efforts. However, our understanding of lycaenid population dynamics has been limited to relatively few examples of long-term monitoring data that have been reported. Here, factors associated with population regulation are investigated using a complete record of a single population of the silvery blue, Glaucopsyche lygdamus Doubleday (Lepidoptera: Lycaenidae). Adults of G. lygdamus were first observed in an annual grassland near Davis, California, in 1982 and were last seen in 2003. Relationships between inter-annual variation in abundance and climatic variables were examined, accounting for density dependent effects. Significant effects of both negative density dependence and climatic variation were detected, particularly precipitation and temperature during winter months. Variation in precipitation, the strongest predictor of abundance, was associated directly and positively with butterfly abundance in the same year. Winter temperatures had a negative effect in the same year, but had a lagged, positive effect on abundance in the subsequent year. Mechanistic hypotheses are posed that include climatic effects mediated through both larval and adult plant resources
Compensation Following Bilateral Vestibular Damage
Bilateral loss of vestibular inputs affects far fewer patients than unilateral inner ear damage, and thus has been understudied. In both animal subjects and human patients, bilateral vestibular hypofunction (BVH) produces a variety of clinical problems, including impaired balance control, inability to maintain stable blood pressure during postural changes, difficulty in visual targeting of images, and disturbances in spatial memory and navigational performance. Experiments in animals have shown that non-labyrinthine inputs to the vestibular nuclei are rapidly amplified following the onset of BVH, which may explain the recovery of postural stability and orthostatic tolerance that occurs within 10 days. However, the loss of the vestibulo-ocular reflex and degraded spatial cognition appear to be permanent in animals with BVH. Current concepts of the compensatory mechanisms in humans with BVH are largely inferential, as there is a lack of data from patients early in the disease process. Translation of animal studies of compensation for BVH into therapeutic strategies and subsequent application in the clinic is the most likely route to improve treatment. In addition to physical therapy, two types of prosthetic devices have been proposed to treat individuals with bilateral loss of vestibular inputs: those that provide tactile stimulation to indicate body position in space, and those that deliver electrical stimuli to branches of the vestibular nerve in accordance with head movements. The relative efficacy of these two treatment paradigms, and whether they can be combined to facilitate recovery, is yet to be ascertained
Building Entry Flood Barrier
The purpose of this project is to develop a flood barrier that would resist flood water from entering through the doorways of a building. The goal is to mitigate extensive flooding within a structure. After the disastrous weather events that impacted American citizens late in the year of 2017, the team was inspired to develop a project to help disaster victims. Through extensive preliminary and market research, it was discovered that flooding is a serious issue that affects people all over the world. A product to stop flooding could benefit people in developed countries, but it could also help citizens of developing countries. After this research, the group was able to strategize and develop a plan to help fight against flooding and lessen the struggle victims endure. After brainstorming multiple solutions to this important problem, the group refined their ideas and settled on a point source flood barrier. This product would fit in doorways and be relatively easy and quick to employ. The team then developed a design, created a 3D model, and built a proof-of-concept prototype. Then testing was done on the prototype to reveal changes that could be made to improve the design. Overall, the team partook in many stages in the design process of a product that could meet the goal of aiding disaster victims
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Becoming Otherwise: A Speculative Ethnography of Anarchival Events
At the heart of the archive lie the questions of what will be repeated and what comes first, questions that ripple through curriculum studies and qualitative research. Whether social media platforms like Facebook or the monuments of white supremacists, archives increasingly mediate relationships with the past and generate monumental controversies. Hung up on archival exclusions and surplus values—the anarchive—this study considered three different archives: a monument dedicated to Harriet Tubman, a prominent social media platform, and two reading groups dedicated to process philosophy and affect studies. Studying the anarchive involved a mixture of ethnographic methods and speculative practices, like fictocriticism, reading groups, and assemblage art. The way these archives came together affected what they did. Rather than static receptacles, they affected and were affected by novel assemblages. Thus, anarchiving—attunement and experimentation with the archive’s virtuality—entailed taking on responsibility for what those archives might yet become
THE TIMBER INDUSTRY IN JACKSON COUNTY, NORTH CAROLINA
The purpose of this thesis is to examine the timber industry in Jackson County, North Carolina. It is hoped that the study may also shed light on lumbering in the Appalachian region. By adapting Ronald D Eller's chronology for the economic development of the Appalachian South, the growth of local timber activities will be considered against the backdrop of the regional experience.This study surveys the early history of logging and sawmillinging the county, with special emphasis on the methods and equipment used. The first commercial firm to attempt serious utilization of Jackson County's resources was the Blue Ridge Lumber Company. An account of this company is offered as is one concerning the activities of the Blackwood Lumber Company. The Blackwood Lumber Company was representative of highly mechanized, large-scale commercial operations which developed within western North Carolina in the 1900s.The section dealing with the more recent period centers around Woody Clifton Hennessee and the Mead Corporation. Hennessee is representative of an independent Appalachian lumber entrepreneur,while the Mead Corporation is a major firm operating in the region,but with its headquarters elsewhere. Also, passing attention is given to the independent circular sawmill operators such as Quince Heddon.The thesis shows how the timber industry in Jackson County served as a vehicle for change from a subsistence agricultural society to a wage-oriented one. The timber industry in this county was not as exploitative as in other areas of Appalachia. It has exerted a positive influence here and will undoubtedly do so in the foreseeable future
Performance analysis of GA and PBIL variants for real-world location-allocation problems.
The Uncapacitated Location-Allocation problem (ULAP) is a major optimisation problem concerning the determination of the optimal location of facilities and the allocation of demand to them. In this paper, we present two novel problem variants of Non-Linear ULAP motivated by a real-world problem from the telecommunication industry: Uncapacitated Location-Allocation Resilience problem (ULARP) and Uncapacitated Location-Allocation Resilience problem with Restrictions (ULARPR). Problem sizes ranging from 16 to 100 facilities by 50 to 10000 demand points are considered. To solve the problems, we explore the components and configurations of four Genetic Algorithms [1], [2], [3] and [4] selected from the ULAP literature. We aim to understand the contribution each choice makes to the GA performance and so hope to design an Optimal GA configuration for the novel problems.We also conduct comparative experiments with Population-Based Incremental Learning (PBIL) Algorithm on ULAP. We show the effectiveness of PBIL and GA with parameter set: random and heuristic initialisation, tournament and fined grained tournament selection, uniform crossover and bitflip mutation in solving the proposed problems
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