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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.
131

Autonomous Terrain Mapping Using COTS Hardware

Anderson, James, Honse, Adam 10 1900 (has links)
ITC/USA 2012 Conference Proceedings / The Forty-Eighth Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2012 / Town and Country Resort & Convention Center, San Diego, California / The paper describes the development of a robotic platform which can autonomously map terrain using a COTS infrared imaging and ranging system. The robotic system is based on an omnidirectional platform, and can navigate typical commercial indoor environments. An on-board processor performs surface reconstruction, and condenses the point clouds generated by the ranging system to mesh models which can be more easily stored and transmitted. The processor then correlates new frames with the existing world model by using sensor odomerty. The robot will autonomously determine the best areas of the environment to map, and gather complete three dimensional color models of arbitrary environments.
132

Improving Quantitative Precipitation Estimation in Complex Terrain Using Cloud-to-Ground Lightning Data

Minjarez-Sosa, Carlos Manuel January 2013 (has links)
Thunderstorms that occur in areas of complex terrain are a major severe weather hazard in the intermountain western U.S. Short-term quantitative estimation (QPE) of precipitation in complex terrain is a pressing need to better forecast flash flooding. Currently available techniques for QPE, that utilize a combination of rain gauge and weather radar information, may underestimate precipitation in areas where gauges do not exist or there is radar beam blockage. These are typically very mountainous and remote areas, that are quite vulnerable to flash flooding because of the steep topography. Lightning has been one of the novel ways suggested by the scientific community as an alternative to estimate precipitation over regions that experience convective precipitation, especially those continental areas with complex topography where the precipitation sensor measurements are scarce. This dissertation investigates the relationship between cloud-to-ground lightning and precipitation associated with convection with the purpose of estimating precipitation- mainly over areas of complex terrain which have precipitation sensor coverage problems (e.g. Southern Arizona).The results of this research are presented in two papers. The first, entitled Toward Development of Improved QPE in Complex Terrain Using Cloud-to-Ground Lighting Data: A case Study for the 2005 Monsoon in Southern Arizona, was published in the Journal of Hydrometeorology in December 2012. This initial study explores the relationship between cloud-to-ground lightning occurrences and multi-sensor gridded precipitation over southern Arizona. QPE is performed using a least squares approach for several time resolutions (seasonal -June, July and August-, 24 hourly and hourly) and for a 8 km grid size. The paper also presents problems that arise when the time resolution is increased, such as the spatial misplacing of discrete lightning events with gridded precipitation and the need to define a "diurnal day" that is synchronized with the diurnal cycle of convection. The second manuscript (unpublished), entitled An Improved QPE Over Complex Terrain by Using Cloud-to-Ground Lightning Occurrences, provides a new method to retrieve lightning-derived precipitation at 5 minutes and 5 Km time and space resolutions. A stationary model that employs spatio-temporal neighboring (Space and Time Invariant model -STI) improves upon the least squares method in the first paper. By applying a Kalman filter to the STI model, lightning-precipitation is retrieved by a dynamic model that changes in time. The results for seasonal and 5 minutes time resolution show that the dynamic model improves the retrievals derived by the STI model.
133

Digital Soil-Landscape Classification for Soil Survey using ASTER Satellite and Digital Elevation Data in Organ Pipe Cactus National Monument, Arizona

Nauman, Travis William January 2009 (has links)
Digital soil mapping supervised and unsupervised classification methods were evaluated to aide soil survey of unmapped areas in the western United States. Supervised classification of landscape into mountains and basins preceded unsupervised classification of data chosen by iterative data reduction. Principal component data reduction, ISODATA classification, Linear combination of principal components, Zonal averaging of linear combination by ISODATA class, Segmentation of the image into polygons, and Attribution of polygons by majority ISODATA class (PILZSA process) comprised steps isolating unique soil-landscape units. Input data included ASTER satellite imagery and USGS 30-m elevation layers for environmental proxy variables representing soil forming factors. Results indicate that PILZSA captured general soil patterns when compared to an existing soil survey while also detecting fluvial soils sourced from different lithologies and unique mountain areas not delineated by the original survey. PILZSA demonstrates potential for soil pre-mapping, and sampling design efforts for soil survey and survey updates.
134

Antropologens roll på slagfältet : En studie av den etiska debatten angående Human Terrain System

Birkeland, Jacob January 2009 (has links)
Den här studien syftar till ett belysa och problematisera kring antropologins närmande av det militära sammanhanget. 2007 utformade USA:s armé en plattform som skulle koordinera och hantera civil kompetens inom områdena antropologi och statsvetenskap. Ämnen som på olika sätt analyserar den ”mänskliga terrängen”. Konceptet ”Human Terrain System” lanserades där akademiker från samhällsvetenskaperna fick söka sig till den militära kontexten för att hjälpa militära beslutsfattare att förstå kulturen, de socioekonomiska förhållandena och religionens roll mm. Hur förhåller sig antropologer till Human Terrain System? Vilka perspektiv finns på antropologin som en del i en militär kontext? Genom att svara på dessa frågeställningar belyses olika resonemang på den tillämpbara antropologin i en militär kontext utifrån den rådande etiska debatten som återfinns inom disciplinen. Implementerandet av antropologiska kunskaper i en den militära kontexten har föranlett till en debatt inom den antropologiska disciplinen. En debatt som lyfter etiska betänkligheter och problematiserar kring vilket antropologins uppdrag är, kan vara och bör vara. Studien granskar det traditionella förhållandet till villkor inom disciplinen, detta illustrerat genom den etiska debatten kring projektet Human Terrin System. Studien slår fast att oavsett hur den enskilde antropologen väljer att förhålla sig till ämnets närmande av det militära så är kontraktet mellan forskare och informant lika centralt som det mellan forskare och uppdragsgivare.
135

ASSESSMENT OF TERRAIN ATTRIBUTE MODELS FOR THE IDENTIFICATION OF EROSION PRONE AREAS SUITABLE FOR THE ESTABLISHMENT OF GRASSED WATERWAYS IN AN AGRICULTURAL FIELD SETTING IN THE OUT BLUEGRASS REGION OF KENTUCKY

Pike, Adam Clellon 01 January 2008 (has links)
The speed and accuracy of conservation planning could be improved if maps indicating areas where grassed waterways should be placed to reduce erosion could be easily created. For five central Kentucky fields, elevation data were obtained with real time kinematic (RTK) global positioning system (GPS) and from US Geological Survey (USGS) digital elevation models (DEMs). Terrain attributes were calculated from these datasets which were used as predictor variables for neural network and logistic regression analyses. Grassed waterway prediction models were developed with these analyses. The type of activation function, type of standardization procedure, number of neurons, number of preliminary runs, and number of hidden layers had little impact on the results of the neural network analysis. Logistic regression and neural network analyses produced similar erosion prediction maps. The type of flow direction algorithm used to calculate terrain attributes did not change prediction maps substantially. Grassed waterways could be predicted in most cases with the RTK data but only in some cases with the USGS data. This modeling approach was robust and could aid conservation planners in identifying suitable areas for waterways more efficiently if accurate elevation data can be acquired.
136

Remote sensing and biophysical monitoring of vegetation, terrain attributes and hydrology to map, characterise and classify wetlands of the Maputaland Coastal Plain, KwaZulu-Natal, South Africa

Grundling, Althea Theresa 30 April 2014 (has links)
The Maputaland Coastal Plain is situated in north-eastern KwaZulu-Natal Province, South Africa. The Maputaland Coastal Plain and underlying aquifer are two separate but inter-linked entities. This area with high permeable cover sands, low relief and regional geology that slopes towards the Indian Ocean, hosts a variety of important wetlands in South Africa (e.g. 66% of the recorded peatlands). The wetlands overlie and in some cases also connect to the underlying regional water-table. The apparent distribution of wetlands varies in response to periods of water surplus or drought, and over the long-term has been reduced by resource (e.g. agriculture, forestry) and infrastructure (e.g. urbanisation) development. Accurate wetland mapping and delineation in this environment is problematic due to the ephemeral nature of wetlands and extensive land-use change. Furthermore the deep aeolian derived sandy soils often lacks soil wetness indicators in the soil profile. It is postulated that the aquifer is the source of water to rivers, springs, lakes and wetlands (and vice versa). However, the role of groundwater in the sustainability of hydro-ecological systems is unclear. Consequently this research attempted to determine spatial and temporal changes in the distribution of these wetlands, their susceptibility to human development, understand the landscape processes and characterise and classify the different wetland types. An underlying assumption of the hydrogeomorphic wetland classification concept in South Africa is that wetlands belonging to the same hydrogeomorphic unit share common features in terms of environmental drivers and processes. Given the above, the objectives of this thesis relating to the north-eastern corner of the Maputaland Coastal Plain are to: 1) Map the distribution of wetlands and their relation to other land-use; 2) Characterise the landscape processes shaping the dynamics of wetland type and their distribution; 3) Classify wetlands by applying hydrogeomorphic wetland classification system. This study used Landsat TM and ETM imagery acquired for 1992 and 2008 (dry) and Landsat ETM for 2000 (wet) along with ancillary data. Wetland type characteristics were described using terrain unit position in the landscape, SRTM DEM, land surveyor elevation measurements along with long-term rainfall records, in situ water-table levels with soil analysis and geology and vegetation descriptions. A conceptual model was used to account for the available data, and output from a hydrology model was used to support the interpretation of wetland distribution and function. Wetlands in the study area include permanent wetlands (swamp forests and reed/sedge wetlands), but the majority of sedge/moist grassland wetlands are temporary systems. The wetland distribution reflects the rainfall distribution and groundwater discharge in lower lying areas. The weathering of the Kosi Bay Formation is a key factor in wetland formation. Because of an increase in clay content with depth, the pore-space and hydraulic conductivity are reduced which causes water to impede on this layer. The nature of the aquifer and regional geology that slope towards the east along with extreme rainfall events in wet and dry periods are contributing drivers of wetland and open water distribution. In 2008 (a dry year) the smaller wetland extent (7%) could primarily identify “permanent” groundwater-fed wetland systems, whereas for the wet year (2000) with larger wetland extent (18%) both “temporary” and “permanent” wetlands were indicated. Comparison between both dry years (1992 and 2008) indicates an 11% decrease in wetland (sedge/moist grassland) and a 7% increase in grassland distribution over time. Some areas that appear to be grassland in the dry years were actually temporary wetland, based on the larger wetland extent (16%) in 2000. The 2008 Landsat TM dataset classification for the entire Maputaland Coastal Plain gave an overall 80% mapping accuracy. Landscape settings identified on this coastal aquifer dominated by dune formations consist of 3 types: plain (upland and lowland), slope and valley floor. Although the wetland character is related to regional and local hydrogeology as well as climate affecting the temporal and spatial variability of the wetlands this research confirms that the patterns and wetland form and function are predominantly shaped by the hydrogeomorphic setting and not the rainfall distribution. The following wetland types were identified: permanent wetlands such as peat swamp forests, peat reed and sedge fens; temporary wetland systems such as perched depressions, and sedge/moist grasslands. The Hydrogeomorphic wetland classification system was applied using a semi-automated method that was 81% accurate. The following hydrogeomorphic units could be identified: one floodplain, i.e., Siyadla River Floodplain, channelled valley-bottoms, unchannelled valley-bottoms, depressions on modal slope values <1%, seepage wetlands on modal slope values 1-2%. However, evaluation of the hydrogeomorphic classification application results suggests that the “flat” hydrogeomorphic class be revised. It did not fit meaningfully on the upland plain area. This research finding concludes wetland function does depend on landscape setting and wetland function is not truly captured by the hydrogeomorphic type classification. Not all depression on the coastal plain function the same way and three types of depressions occurs and function differently, i.e., perched depression with no link to the regional water-table vs. depressions that are linked with the regional water-table on plain, slope and valley floor landscape settings. Overall, this research study made a useful contribution in characterising and classifying wetland type and distribution for a high priority wetland conservation area in South Africa. Applying similar methods to the broader Maputaland Coastal Plain will particularly benefit from the research findings. The importance of using imagery acquired in wet and dry periods as well as summer and winter for a more comprehensive wetland inventory of the study area, is stressed. To manage the effects of climate variability and development pressure, informed land-use planning and rehabilitation strategies are required based on landscape analysis and interpretation.
137

Mapping the effects of dry sclerophyll vegetation within the battlespace using the Leica ADS40 and GIS

Jackson, Anthony Edward January 2006 (has links)
1st Topographical Survey Squadron, Royal Australian Engineers, provides deployable geospatial support to the Australian Defence Force. Part of this role is the production of products for use by commanders. These products provide commanders at all levels with mission specific and up to date knowledge of the terrain that he will encounter on the battlespace. Currently 1st Topographical Survey Squadron provides products that contain manmade features, hydrography, slope, surface configuration and vegetation as displayed on current mapping products. They do not provide an accurate portrayal of the effect that vegetation characteristics have on the battlespace. Introducing these types of features will give the commander a greater knowledge of the terrain and environment that he will encounter, and will greatly improve the planning and success of the campaign. This research explored to what extent the accuracy of the terrain analysis products currently produced by 1st Topographical Survey Squadron would increase by adding a more detailed portrayal of vegetation extracted from remote sensing data.
138

Design extrême : objets témoins d'une vie de kamikase /

Boulianne, Chantale, January 2000 (has links)
Mémoire (M.A.) -- Université du Québec à Chicoutimi, 2000. / Bibliogr.: f. 65. Document électronique également accessible en format PDF. CaQCU
139

Szenarien der klimatischen Auslösung alpiner Hangrutschungen Simulation durch Downscaling allgemeiner Zirkulationsmodelle der Atmosphäre /

Dehn, Martin. Boesler, Klaus-Achim. January 1999 (has links)
Originally presented as the author's Thesis (doctoral)--Universität Bonn, 1998. / Includes bibliographical references (p. 91-99).
140

Szenarien der klimatischen Auslösung alpiner Hangrutschungen Simulation durch Downscaling allgemeiner Zirkulationsmodelle der Atmosphäre /

Dehn, Martin. Boesler, Klaus-Achim. January 1999 (has links)
Originally presented as the author's thesis (doctoral)--Universität Bonn, 1998. / Includes bibliographical references (p. 91-99).

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