Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 19 of 19 for “"Sky conditions"”.
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New and Improved Methods to Characterize, Classify, and Estimate Daily Sky Conditions for Solar Energy Applications
… and classification method for daily sky conditions by using the daily sky clearness index (KD) and the daily probability of persistence (POP-KD) that can be derived from ground-based irradiance measurement data. Quality of daily solar irradiance is characterized by a newly proposed …
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Daylight modeling for energy efficiency and visual comfort in buildings
… determination of the angular distribution of the sky's luminance. Daylight is strongly determined by sky conditions. The CIE/ISO standard provides a good general framework to represent the real conditions of the sky, covering the entire probable spectrum of skies, and has been used as a reference …
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Daylight and planning in Europe
… factor method regardless of prevailing weather conditions. While this method may be used for overcast sky conditions, it can be argued that it is not appropriate for clear skies. A relationship emerged which forms the basis for the average total daylight factor calculation in an urban canyon, …
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Application and simulation of imaging Fabry-Perot interferometers to observe the upper atmosphere
… accuracy of FPI estimates depends greatly on the sky conditions, we then develop novel methods based upon FPI measurements to remove data collected during cloudy weather. The methods described do not require a collocated imaging system or other instrument to determine sky conditions and, …
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A system for optimizing interior daylight distribution using reflective Venetian blinds with independent blind angle control
… the window under most clear sunny and overcast sky types. Under overcast sky conditions, all blinds are set to a uniform angle which optimizes light redirection to 10 m. For cases of direct solar incidence, alternating blinds are used for shading and light redirection and adjusted with changing …
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Performance characteristics of a multiple use Ku-band satellite network
… performance of the network during clear sky conditions and during periods of rain fade conditions are calculated. To aid in these calculations the software package LAMP was developed. detailed system design of a VSAT network is given in later chapters. The development of VSAT networks …
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Satellite-based estimates of net radiation and modeling the role of topography and vegetation on inter-annual hydro-climatology
… shortcomings: difficulty in dealing with cloudy sky conditions and reliance on study-site specific ancillary ground data. In this work, a framework of estimating net radiation from the MODerateresolution Imaging Spectroradiometer (MODIS) data is presented that is applicable under all-sky …
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The Influence of Overstory Structure on Understory Light Availability in a Longleaf Pine (Pinus palustris Mill.) Forest
… techniques at different time scales and sky conditions. The methods assessed performed differently depending on the sky condition and time of year when the sample was taken. To estimate annual photosynthetic photon flux density transmittance (annual %PPFD), the use of a 10-minute average …
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A methodology for detailed calculation of illuminance levels and light dimming factors in a room with motorized blinds integrated in an advanced window
… of blind till angle, solar incidence angle and sky conditions. (2) The illuminance distribution on the work plane due to daylight is determined. (3) The electrical light level required to achieve the necessary total illuminance level on the work plane is computed and light dimming levels are …
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Characterization of Pyranometer Thermal Offset and Correction of Historiacal Data
… when measuring diffuse irradiance under clear sky conditions. The thermal offset is characterized by monitoring the temperature gradient between the dome and detector using thermistors at key locations. The temperatures are acquired by using thermistors. Relationships between the thermal offset …
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Laser beacon tracking for free-space optical communication on small-satellite platforms in low-earth orbit
… with low fade probability during various sky conditions, sufficient to support a high-rate FSO communication link on a CubeSat platform on low-Earth orbit. The high-level Nanosatellite Optical Downlink Experiment (NODE) system architecture, the beacon camera conceptual design as well as …
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Assessing Broadband and Spectral Irradiance Variability for Solar Nowcasting Using Statistical Analysis and Machine Learning
… prediction accuracy. It was found that under all sky conditions, the inclusion of spectral irradiance data improved forecasting performance compared to only using broadband irradiance. A ramp regime classification algorithm is then described, which enables the training and testing specialized ramp …
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The Physiological Ecology of Fraser FIr in Southern Appalachian Cloud Forests
… of these forests during cloud immersed conditions, compared to cloudy and sunny (clear sky) conditions. During cloud immersed periods, sunlight levels were low and often below the photosynthetic compensation point of Fraser fir. Leaf and air temperatures were substantially lower in cloud …
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Energy-Efficient and Trustworthy Location-Based Services for Next-Generation IoT
… System (GPS), provide high accuracy under open-sky conditions but fall short in IoT deployments due to their high energy demands, unreliable indoor performance, and vulnerability to interference and malicious threats. These limitations have stimulated extensive research on GPS-free localization …
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Comprehensive Performance Analysis of Localizability in Heterogeneous Cellular Networks
… (GPS) is usually sufficient in outdoor clear sky conditions, its functionality is limited in urban canyons and indoor locations due to the absence of clear line-of-sight between the MD to be localized and a sufficient number of navigation satellites. In such scenarios, the ubiquitous nature of …
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Surface reflection model estimation from naturally illuminated image sequences
… that is, a scene which is illuminated by sun and sky light alone. This is a departure from the traditional analysis of laboratory scenes, which are illuminated by idealised light sources with positions and radiance distributions that are precisely controlled. Natural illumination presents a …
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On the Improvements of Boundary-Layer Representation for High Resolution Weather Forecasting in Costal-Urban Environments
… have improved forecasting near-surface weather conditions, a comprehensive approach to represent urban impacts on the PBL is still limited. Improved PBL representation can lead to better weather and climate forecasts, benefitting human health, risk reduction from extreme weather events, improved …
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The Observation, Modeling, and Retrieval of Bio-Optical Properties for Coastal Waters of the Southern Chesapeake Bay
… from IOPs and sky conditions (e.g. cloud coverage and solar zenith angle). Compared to the significant overestimation of the simple <em>Gordon</em> [1989] model for particle-rich environments, PZ06_<em>Ed</em> agreed with <em>Hydrolight</em>® with < 6% of the …
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Assessing solar radiation components over the alpine region Advanced modeling techniques for environmental and technological applications.
… and aerosols, and shading, reflections and sky obstructions by terrain. Ground-based measurements capture all these effects, but are unevenly distributed and poorly available in the Italian Alps. Consequently they are inadequate for assessing spatially distributed incoming radiation through …