Thesis (M. Phil.)--University of Hong Kong, 1999. / Includes bibliographical references (leaves 117-124).

The resolution of spatial data has increased over the past decade making them more accurate in depicting landform features. From using a 60m resolution Landsat imagery to resolution close to a meter provided by data from Unmanned Aerial Systems, the number of pixels per area has increased drastically. Topographic features derived from high resolution remote sensing is relevant to measuring agricultural yield. However, conventional algorithms in Geographic Information Systems (GIS) used for processing digital elevation models (DEM) have severe limitations. Typically, 3-by-3 window sizes are used for evaluating the slope, aspect and curvature. Since this window size is very small compared to the resolution of the DEM, they are mostly resampled to a lower resolution to match the size of typical topographic features and decrease processing overheads. This results in low accuracy and limits the predictive ability of any model using such DEM data. In this dissertation, the landform attributes were derived over multiple scales using the concept of sliding window-based aggregation. Using aggregates from previous iteration increases the efficiency from linear to logarithmic thereby addressing scalability issues. The usefulness of DEM-derived topographic features within Random Forest models that predict agricultural yield was examined. The model utilized these derived topographic features and achieved the highest accuracy of 95.31% in predicting Normalized Difference Vegetation Index (NDVI) compared to a 51.89% for window size 3-by-3 in the conventional method. The efficacy of partial dependence plots (PDP) in terms of interpretability was also assessed. This aggregation methodology could serve as a suitable replacement for conventional landform evaluation techniques which mostly rely on reducing the DEM data to a lower resolution prior to data processing. / National Science Foundation (Award OIA-1355466)

The world’s oceans absorb a significant percentage of anthropogenic carbon emissions, and CO2 levels have profound effects on the marine environment. Of primary concern is the acidification of the oceans due to dissolved CO2. The goal of this research is to design new sensing technologies for deployment in the marine environment to detect CO2 pollutant. A series of carbon dioxide (CO2) receptors that are complexed to fluorene oligomers were studied computationally. In chapter 1, an overview of CO2 chemistry and various CO2 sensors is discussed. A short overview of the method (Kohn-Sham density functional theory and time-dependent density functional theory (TDDFT)) employed in this work is given. Chapter 2 presents a study on the interaction energy and electronic excitations of fluorene-receptors as CO2 sensors. The aim of this work is to gain an understanding of the nature of interactions between these receptors and CO2. The structural, electronic, and optical properties of these receptor complexes have been determined computationally. The monomer-receptor complexes show remarkable redshifts in their absorption spectra, which decrease on moving to dimer and trimer-receptor complexes (all blue-shifted).

Partial discharge testing is a nondestructive method of identifying possible premature insulation breakdown. Magnet wires are used in various electrical equipment like injection coils, solenoids, small transformers and motors. Winding wires used in high voltage systems are subjected to several stresses during operation, which considerably lowers their lifetime. A prolonged combined effect of these stresses causes aging of the wires, inception of partial discharge activity, and degradation of the organic material in the enamel coating and varnish used by the manufacturer. The tests were conducted for AWG 30 and AWG 31 twisted magnet wire samples. The samples are aged under accelerated conditions of high frequency, temperature, and pulsed voltages. As well as conventional sinusoidal voltages. This thesis is focused on the results of voltage, frequency, and temperature stresses on the magnet wires. The partial discharge inception voltage (PDIV) and breakdown voltages are measured for different twisted wire samples. A software tool is utilized to study these partial discharge patterns. Evaluation of the parameters charge intensity, pulse count, and pulse phase position are presented in 2- and 3-dimensional plots.

M.A. / Please refer to full text to view abstract

Mathcad Prime 2.0 - Was ist neu? - Excel Komponente - 3D-Plots - Symbolik - Verbesserung der Performance CREO und Mathcad - Ein starkes Team

International Telemetering Conference Proceedings / October 27-30, 1997 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Flight Safety concerns increase proportionally with increasing missile performance. These concerns are greatest in the near launch arena where a missile has the greatest potential energy. Systems such as radar, GPS tracking systems, and optics are normally of limited use in this arena for a number of reasons. A system was required that would provide useful tracking data in the first few seconds of a missile launch. This system has met that requirement providing nominal path deviation data from the launcher out to as much as 120 seconds. The tracking system described herein uses the principle of radio interferometry to derive phase difference measurements between carefully spaced antennas. These measurements are transmitted to the Operational Display Facility and converted to a usable angular deviation plot for use by Flight Safety Personnel. This paper provides an elementary radio interferometer system background and discusses this particular system setup and use. Some detail is provided on the premission simulation and setup of the system as well as the real-time display setup and output of the final data product.

<p>Many hydrocarbon reservoirs are situated in barren sequences that display poor stratigraphic control. Correlation between the wells can become extremely difficult and traditional correlation techniques can prove to be inadequate. Past studies have shown that trace and major element concentrations can be used as a correlation tool. This practice of using geochemical fingerprints to characterize between wells is called Chemostratigraphic analysis. (Pearce et al, 1999) Chemostratigraphy has been recognized as a very important correlation technique as it can be used for rocks of any age, in any geological setting as well as sequences that are traditionally defined as barren. Chemostratigraphic analyses can be used as a means of getting rid of ambiguities within data produced by traditional correlation methods such as Biostratigraphy, Lithostratigraphy and Geophysical Logging. In areas where stratigraphic data is not available it can be used to construct correlation frameworks for the sequences found in the area. The motivation behind this study is that the research is not only worthy of academic investigation, but can also provide the industry with new insights into areas that were previously misunderstood because traditional correlation methods were not adequate. The study area, the Orange basin, is located offshore South Africa and is largely underexplored. The basin, that hosts two gas field namely the Ibhubesi and the Kudu gas fields, has large potential but in the past has not been given due attention with only 34 wells being drilled in the area. The Orange basin has recently been the topic of investigation because of the belief that it may be hosts to more hydrocarbons. This study will utilise Chemostratigraphy to attempt to provide geological information on this relatively under-explored basin. The aim of this research study is to produce a chemostratigraphic framework -scheme for the Orange Basin in order to facilitate reservoir scale interwell correlation. The Objectives of this research study will be to identify chemostratigraphic units or indices, to prove the adequate use of chemostratigraphy as an independent correlation technique and to integrate the chemostratigraphy and petrophysical characteristics of the four wells to facilitate lithological identification.</p>

Kadastriniai (geodeziniai) matavimai – veiksmai, kuriais identifikuojamas nekilnojamasis daiktas, atliekamas tikslus suformuotų žemės sklypų plotų nustatymas, parengiamas žemės sklypo planas, bei suformuojama ir parengiama nustatytos formos nekilnojamojo daikto kadastro duomenų byla. Straipsnyje analizuojami Panevėžio rajono sodininkų bendrijų sodų ir asmeninio ūkio žemės sklypų kadastro duomenų pokyčiai tarp Nekilnojamojo turto registre įregistruotų sklypų kadastro duomenų ir geodezinių matavimų metu nustatytų duomenų. Apžvelgiamas kadastrinių matavimų teisinis reglamentavimas, aptariamas Panevėžio rajono sodininkų bendrijų sodų, asmeninio ūkio, bei namų valdų žemės sklypų privatizavimas, pateikiami konkretūs preliminarių ir kadastrinių matavimų metu nustatytų kadastro duomenų pavyzdžiai. / Cadastral (surveying) measurements - the action, which identified the immovable object, the establishment of a precise determination of surface area, a plot plan, and formed fixed shape and a real estate cadastre data file. The article analyzes the Panevezys District Gardening community garden and private agricultural land plots cadastral data changes between the real estate register land cadastre data and geodetic measurements in the data. Overview of the legal regulation of cadastral measurements, discussed in Panevezys District Gardening community garden, private farm, house and land holdings of land privatization, and the specific preliminary and cadastral measurements of the time set for the cadastral data.

<p>Many hydrocarbon reservoirs are situated in barren sequences that display poor stratigraphic control. Correlation between the wells can become extremely difficult and traditional correlation techniques can prove to be inadequate. Past studies have shown that trace and major element concentrations can be used as a correlation tool. This practice of using geochemical fingerprints to characterize between wells is called Chemostratigraphic analysis. (Pearce et al, 1999) Chemostratigraphy has been recognized as a very important correlation technique as it can be used for rocks of any age, in any geological setting as well as sequences that are traditionally defined as barren. Chemostratigraphic analyses can be used as a means of getting rid of ambiguities within data produced by traditional correlation methods such as Biostratigraphy, Lithostratigraphy and Geophysical Logging. In areas where stratigraphic data is not available it can be used to construct correlation frameworks for the sequences found in the area. The motivation behind this study is that the research is not only worthy of academic investigation, but can also provide the industry with new insights into areas that were previously misunderstood because traditional correlation methods were not adequate. The study area, the Orange basin, is located offshore South Africa and is largely underexplored. The basin, that hosts two gas field namely the Ibhubesi and the Kudu gas fields, has large potential but in the past has not been given due attention with only 34 wells being drilled in the area. The Orange basin has recently been the topic of investigation because of the belief that it may be hosts to more hydrocarbons. This study will utilise Chemostratigraphy to attempt to provide geological information on this relatively under-explored basin. The aim of this research study is to produce a chemostratigraphic framework -scheme for the Orange Basin in order to facilitate reservoir scale interwell correlation. The Objectives of this research study will be to identify chemostratigraphic units or indices, to prove the adequate use of chemostratigraphy as an independent correlation technique and to integrate the chemostratigraphy and petrophysical characteristics of the four wells to facilitate lithological identification.</p>