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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Rankos ir žiūros taško judesių koordinacija panaudojant labirinto testą / Coordination of eye-hand movements using labyrinth path

Kulvelis, Saulius 04 August 2011 (has links)
Žmogaus natūralus elgesys puikiai parodo sinchronizuotus akių ir rankos judesius. Akių-rankos koordinacija naudinga tiriant alternatyvius kompensacinius įtaisus, kurie gelbsti žmogaus ir kompiuterio sąveikai, kai reabilituojami žmonės su negale. Tiriamieji buvo paprašyti pravesti ranka kursorių labirinto trajektorija (pakankamai dideliu greičiu). Eksperimento metu akių judesiai buvo fiksuojami "EyeGaze" sistema sukurta "LC technologies LTd.". Rezultatuose nustatytos akių-rankos judesių koordinacijos strategijos: GJ - šuolinė ir GMS - sekimo strategija. / Human behavior in manual control coordinated by vision illustrates perfect synchronization between the gaze and position of the target, which is controlled by hand. Investigation of eye-hand coordination is useful for alternative control of computer cursor and for an assessment and rehabilitation of a sensorimotor system of patients. Subjects were asked to move the target along the labyrinth’s path quickly enough. During all experiments, movements of both eyes were recorded with eye tracker “EyeGaze System” produced by “LC Technologies Ltd.” Gaze tracking instrumentation was setup so, that to 1 deg eye angle corresponds to 46 pixels on computer screen. The results showed two eye-hand coordination strategies Gaze Jumps (GJ) and Gaze Moves Smoothly (GMS) during guiding self-moved target along Labyrinth path can be defined. During GJ strategy gaze elicit eye jumps in the direction of the future path. Average amplitude of the jumps is around 1.5 deg and frequency is in the 2-3 Hz range. During GMS strategy gaze is concentrated on the self-moved target and leads it only by small average distance (0.1-0.2 deg).
22

An Enhanced Data Model and Tools for Analysis and Visualization of Levee Simulations

Griffiths, Thomas Richard 15 March 2010 (has links) (PDF)
The devastating levee failures associated with hurricanes Katrina and Rita, and the more recent Midwest flooding, placed a spotlight on the importance of levees and our dependence on them to protect life and property. In response to levee failures associated with the hurricanes, Congress passed the Water Resources Development Act of 2007 which established a National Committee on Levee Safety. The committee was charged with developing recommendations for a National Levee Safety Program. The Secretary of the Army was charged with the establishment and maintenance of a National Levee Database. The National Levee Database is a critical tool in assessing and improving the safety of the nation's levees. However, the NLD data model, established in 2007, lacked a structure to store seepage and slope stability analyses – vital information for assessing the safety of a levee. In response, the Levee Analyst was developed in 2008 by Dr. Norm Jones and Jeffrey Handy. The Levee Analysis Data Model was designed to provide a central location, compatible with the National Levee Database, for storing large amounts of levee seepage and slope stability analytical data. The original Levee Analyst geoprocessing tools were created to assist users in populating, managing, and analyzing Levee Analyst geodatabase data. In an effort to enhance the Levee Analyst and provide greater accessibility to levee data, this research expanded the Levee Analyst to include modifications to the data model and additional geoprocessing tools that archive GeoStudio SEEP/W and SLOPE/W simulations as well as export the entire Levee Analyst database to Google Earth. Case studies were performed to demonstrate the new geoprocessing tools' capabilities and the compatibility between the National Levee Database and the Levee Analyst database. A number of levee breaches were simulated to prototype the enhancement of the Levee Analyst to include additional feature classes, tables, and geoprocessing tools. This enhancement would allow Levee Analyst to manage, edit, and export two-dimensional levee breach scenarios.
23

Groundwater Flow Across the Coyote Wash Fault and Cedar Mesa Anticline near St. Johns, Arizona

Latour, Stephanie Lynn 14 August 2023 (has links) (PDF)
As the demand for water increases across the southwestern United States, the region's utilization of and dependence on water stored in groundwater aquifers has risen in kind. The Coconino Aquifer (C-aquifer) underlies much of the southwestern Colorado Plateau and is a primary source of groundwater in northeastern Arizona. One of the largest commercial users of water from the C-aquifer in Apache County, Arizona, is Springerville Generating Station, a coal-fired power plant owned and operated by Tucson Electric Power. The area surrounding the power plant, located between the cities of Springerville and St. Johns, Arizona (the Springerville-St. Johns area), is geologically complex: it contains the Cedar Mesa anticline, an underlying CO2 reservoir, extensive travertine deposits, and several faults, including the Coyote Wash fault. The Coyote Wash fault and Cedar Mesa anticline play a significant role in the relationships between the St. Johns CO2 gas field, groundwater flow, and the travertine deposits. Yet, the interaction between the structures and the effect they have on groundwater flow is poorly constrained. By mapping the subsurface geology utilizing borehole records and by creating a groundwater model of the area, this study determined that the Cedar Mesa anticline acts as a partial horizontal barrier to groundwater flow, whereas the Coyote Wash fault does not act as such a barrier. Particle tracking for the model indicates that despite the reduced water volume in the aquifer after decades of groundwater extraction, flow still occurs across the hinge of the Cedar Mesa anticline, accelerated by active pumping wells located west of the anticline axis. The model indicates that prior to the activation of the pumping wells, outflow from the C-aquifer would have occurred with greater frequency to Lyman Lake and along the extent of the Little Colorado River located downstream from the lake. The study also identified a zone of high hydraulic conductivity located between the Cedar Mesa anticline and the Coyote Wash fault that continues west of the Coyote Wash fault and may align with the Buttes anticline. This model of groundwater flow conditions improves the understanding of the complex subsurface geology and groundwater flow dynamics in the area.

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