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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.
301

WATERSHED SENSOR NETWORK NON-LINE-OF-SIGHT DATA TELEMETRY SYSTEM

DORSEY, PAUL 08 October 2007 (has links)
No description available.
302

Remote Sensing of the Climate and Cryosphere of Nares Strait, Northwest Greenland

Decker, David T. 01 September 2010 (has links)
No description available.
303

A Framework for Leading at a Distance

Steve Drohan (18265846) 28 March 2024 (has links)
<p dir="ltr">This mixed-method grounded theory study developed and tested a new framework for leading geographically dispersed teams. With the dramatic shift to remote work due to the COVID-19 pandemic, leaders now face new challenges in developing corporate strategies and approaches to leadership without proximity to their teams. However, existing leadership literature has yet to catch up to this new reality.</p><p dir="ltr">Grounded in interviews with business leaders and a quantitative survey of 100 leaders and 100 employees, this study identified communication frequency and trust-building as vital for reducing uncertainty. It also found that promoting employee well-being requires relationship-centered leadership and constructing inclusive cultures. Ultimately, leading at a distance requires adapting leadership development and reevaluating organizational design to focus on alignment, transparency, and culture-building.</p><p dir="ltr">The resulting framework identifies specific leader competencies needed for remote management. It emphasizes the importance of leader visibility, constructive feedback practices, and crisis readiness. The framework highlights new imperatives in meeting design, goal-setting, professional development, and performance management. Finally, it calls for policies that promote work-life balance through comprehensive flexibility.</p><p dir="ltr">This study provides theoretical and practical guidance with hybrid and remote work arrangements likely to persist post-pandemic. It demonstrates the effectiveness of grounded theory methodology in new research contexts. The framework presented lays the foundation for leadership approaches that empower productivity and well-being across distributed teams.</p>
304

Phenology, light use efficiency, and ecosystem productivity in temperate deciduous forests

Lee, Leticia X. 06 September 2024 (has links)
Terrestrial ecosystems provide a substantial carbon sink that helps mitigate climate change, sequestering roughly 30% of anthropogenic carbon emissions annually. However, the long-term future of this sink is not well understood. In this dissertation, I use satellite remote sensing, in-situ measurements, and models to improve understanding of the nature and magnitude of spatial and temporal variation in the primary productivity of Eastern Deciduous Forests of the United States. In my first research chapter, I use remote sensing to model to the phenology of two key variables that control forest productivity: leaf area index (LAI) and the fraction of absorbed photosynthetically active radiation (fAPAR). Results show that the relationship between remotely sensed vegetation indices and both LAI and fAPAR is strongly influenced by systematic variation in near infrared reflectance arising from seasonal changes in canopy shadow fraction that are independent of physical changes in forest canopy properties. In my second research chapter, I use estimates of gross primary production (GPP) derived from eddy covariance measurements at four temperate deciduous sites to model the phenology and controls on light use efficiency (LUE) within and across sites. Results show that multiple modes of variation in incoming radiation dominate daily and seasonal variation in LUE, and provide a refined basis for understanding how variability in environmental controls affect LUE and how the strength of these drivers change throughout the growing season. In my third research chapter, I use the long-term record of Landsat imagery, in-situ phenological observations, and estimates of GPP derived from eddy covariance measurements at two temperate deciduous forest sites to investigate how phenology controls interannual variability in GPP at these sites. Results demonstrate that phenology metrics derived from remote sensing are consistent with in-situ measurements, and that interaction between the timing of growing season anomalies and incoming radiation explains a significant proportion of interannual variation in GPP. Taken together, results from this dissertation demonstrate how variation in phenology and LUE control variation in deciduous forest productivity, which is essential for reducing uncertainty in how future climate changes will impact the carbon budget of deciduous forest ecosystems.
305

Characterization of sea ice surface topography using Light Detection and Ranging (LiDAR)

Jack, Landy 23 December 2015 (has links)
Where once the Arctic basin held predominantly old, thick perennial sea ice, it is now increasingly occupied by young, thin seasonal ice. The sea ice surface topography, which affects and is affected by many of the physical processes operating at the interface between ocean, sea ice and atmosphere, is closely related to the age and type of sea ice cover. In this thesis, new methods are presented for measuring and understanding sea ice topography using Light Detection and Ranging (LiDAR) technology. A new technique is presented for parameterizing the micro-scale roughness of sea ice using terrestrial LiDAR. Field, laboratory and numerical experiments have been carried out to test the precision and accuracy of the technique, and calibrations have been developed for correcting field observations of surface roughness for known biases. Results obtained using this technique have been applied in several microwave remote sensing and electromagnetic-wave scattering model studies of snow-covered and melting sea ice. Terrestrial and satellite LiDAR observations are acquired and combined in a further study to examine how sea ice surface topography regulates the melting of ice during the Arctic summer. Observations from a field program in the Canadian Arctic show that minor variations in the roughness of pre-melt sea ice topography can affect significant variations in the melt pond coverage at the ice surface in summer. Numerical simulations are used to develop a quantitative understanding of these findings and, when applied to satellite observations, explain most of the spatial variation in Arctic summer ice melting rates. Results suggest that a recent reduction in sea ice roughness, caused by progressive changes in the type of sea ice resident in the Arctic Ocean, has accelerated the summer melting and decline of the Arctic sea ice cover. / May 2016
306

Using Variable Coding and Modulation to Increase Remote Sensing Downlink Capacity

Sinyard, David 10 1900 (has links)
ITC/USA 2010 Conference Proceedings / The Forty-Sixth Annual International Telemetering Conference and Technical Exhibition / October 25-28, 2010 / Town and Country Resort & Convention Center, San Diego, California / Remote sensing satellites are typically low earth orbit, and often transmit the data gathered with the remote sensors to ground stations at locations on earth. These transmissions are band limited, and must operate within a 375 MHz bandwidth in the X-Band spectrum. This can present a limitation to the amount of data that can be transmitted during the short duration of a pass (typically less than 15 minutes). It is then highly desirable to increase the bandwidth efficiency of a system for data transmission in a remote sensing downlink. This paper describes a method of achieving higher efficiency by pre-programming the satellite to adjust the modulation and coding based in at least part on the slant range to the receiving ground station. The system uses variable coding and modulation to adjust to the slant range to the ground station to achieve a throughput increase of more than 50% of the data transferred during a pass using the currently accepted technology.
307

Vegetation parameter retrieval from hyperspectral, multiple view angle PROBA/CHRIS data

Kamalesh, Vidhya Lakshmi January 2011 (has links)
No description available.
308

THE ESTIMATION AND SCALING OF LAND-SURFACE FLUXES OF LATENT AND SENSIBLE-HEAT WITH REMOTELY SENSED DATA OVER A GRASSLAND SITE

Humes, Karen Sue, Sorooshian, Soroosh January 1993 (has links)
The overall topic of the research described in this dissertation was the partitioning of available energy at the Earth's surface into sensible and latent heat flux, with an emphasis on the development of techniques which utilize remotely sensed data. One of the major objectives was to investigate the modification of existing techniques, developed over agricultural surfaces, to "natural" ecosystems (i.e., non -agricultural vegetation types with variable and incomplete canopy cover). Ground -based measurements of surface fluxes, vegetation cover, and surface and root -zone soil moisture from the First ISLSCP (International Land Surface Climatology Program) Field Experiment (FIFE) were used to examine the factors controlling the partitioning of energy at ground stations with contrasting surface characteristics. Utilizing helicopter -based and satellite -based data acquired directly over ground -based flux stations at the FINE experimental area, relatively simple algorithms were developed for estimating the soil heat flux and sensible heat flux from remotely sensed data. The root mean square error (RMSE) between the sensible heat flux computed with the remotely sensed data and the sensible heat flux measured at the ground stations was 33 Wm 2. These algorithms were then applied on a pixel -by -pixel basis to data from a Landsat -TM (Thematic Mapper) scene acquired over the FIFE site on August 15, 1987 to produce spatially distributed surface energy- balance components for the FIFE site. A methodology for quantifying the effect of spatial scaling on parameters derived from remotely sensed data was presented. As an example of the utility of this approach, NDVI values for the 1,IFE experimental area were computed with input data of variable spatial resolution. The differences in the values of NDVI computed at different spatial resolutions were accurately predicted by an equation which quantified those differences in terms of variability in input observations.
309

The effects of vegetation on island geomorphology in the Wax Lake Delta, Louisiana

Smith, Brittany Claire 23 September 2014 (has links)
Understanding how deltas build and maintain themselves is critical to predicting how they will respond to perturbations such as sea level rise. This is especially an issue of interest in coastal Louisiana, where land loss is exacerbated due to subsidence and decreased sediment supply. Feedbacks between ecology and geomorphology have been well documented in tidal environments, but the role of vegetation in delta morphodynamics is not well understood. This study investigates spatial and temporal correlations between vegetation succession and sediment accumulation at the Wax Lake Delta in Louisiana. I established a 2500 m long transect along the western levee of Pintail Island, capturing the full range of island elevations and the transition from bare sediment to herbaceous plants and trees. Shallow (50-100 cm deep) sediment cores taken along this transect were analyzed for particle size, organic matter content, and bulk density, and dated using ²¹⁰Pb. The resulting sedimentation rates and composition trends over time were compared to remote sensing-based analyses of temporal changes in island topography and flooding frequency derived from historical Landsat images. We found that the topography of Pintail Island has developed from a non-systematic arrangement of elevations to a discrete set of levees and intra-island platforms with distinct vegetation types, designated as high marsh, low marsh, and mudflat habitat. This elevation zonation is consistent with alternative stable state theory as so far applied to tidal salt marsh systems. At all but the youngest sampling site, sediment cores showed a significant decrease in organic matter content and a significant increase in grain size with depth. The total organic matter contribution to vertical growth was not sufficient to account for all the elevation change required to achieve the differentiation from low marsh to high marsh deduced from the time-lapse Landsat imagery analysis. Mineral sediment accumulation rates suggested that elevation growth was accelerating or holding steady over time, in contrast to theory suggesting rates should slow as elevation increases. These results provide an empirical foundation for future mechanistic models linking mineral sedimentation, organic sedimentation, vegetation succession, elevation change, and flood frequency in the delta. / text
310

Aged Electricity Distribution Asset Replacement

McFarlane, Andrew Ian January 2014 (has links)
Major segments of the Marlborough Lines Ltd (MLL) 11kV electricity distribution network are positioned within remote areas of the Marlborough region including the Marlborough Sounds, the Awatere and Wairau Valleys and the North Eastern cost of the South Island. The majority of these remote rural lines are due for replacement within the coming 20 years in order to maintain safety and reliability. The increased maintenance costs of operating rural electricity lines and the number of customers they serve often results in the line being uneconomic to operate. This investigation determines the current economical efficiency of the Sounds Feeder, a segment of line in the Marlborough Sounds. The financial, social and regulatory implications of the continued operation of this section of the network after performing distribution renewals are assessed in order to define the likely impacts of wide spread asset renewal to MLL and its customers across the coming 20 years.

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