Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 85-88). Also available via the Internet.

No description available.

Automatic interpretation of images from Earth Resources Technology Satellite-1 (ERTS-1, now called LANDSAT) can be used in a variety of applications with considerable accuracy. Most systems, however, classify strictly on a point by point basis, making no use of any spatial knowledge. Standard photo-interpretation techniques are combined with some techniques from artificial intelligence to produce an increase in accuracy over a point-by-point classification method. Traditional classification methods are used to obtain an initial segmentation of the image. Then, a controlled region merging process allows the regions with unambiguous interpretations to influence the interpretation of neighbouring ambiguous regions, thereby introducing considerable context sensitivity into the interpretation process. Results are given of an experiment to interpret areas of different forest cover. / Science, Faculty of / Computer Science, Department of / Graduate

Proceedings, 2nd ARETS Symposium, University of Arizona / Westward Look Resort, Tucson, Arizona, Nov. 2, 3, 4 1971.

The Eastern Shores of Lake St Lucia forms part of the ecologically important Greater St Lucia Wetland Park, designated a World Heritage Site in 1999. The landscape is characterised by surface water, a high water table and numerous wetlands. Little is known about the distribution and temporal fluctuations of this surface water and its relationship to the wetlands. This study uses remote sensing to examine the relationship by mapping the extent of seasonal, ephemeral and permanent surface water on the Eastern Shores. Much of the surface water occurs in conjunction with emergent vegetation and is not easily mapped using hard classification methods. Neither a cluster analysis nor a maximum likelihood classification were able to map the subtle variations of the water-vegetation mix. Much more successful was the application of spectral mixture analysis using image endmembers of water, woody vegetation and non-woody vegetation. This technique was applied to seven Landsat Thematic Mapper images from 1991, 2001 and 2002. Steep slopes, forests and bare sand were masked out prior to classification. Maps of water extent were produced for each of the seven study dates. Mapping accuracy was verified against rainfall, with high correlations being obtained against rainfall accumulated over six months and longer. Long-term rainfall patterns were reflected in the surface water distribution, with inundation being more extensive when accumulated rainfall was high. Fire scars reduced the accuracy of the spectral mixture analysis but these scars could be identified from the thermal image bands. The largest open water body in the study area was Lake Bhangazi. Large extents of surface water were also found in the Mfabeni swamp and the wilderness area to the north where water concentrations of 90% were measured during wet periods. Surface water present near Brodies Crossing during wet periods was less evident when rainfall was lower. No inundation was recorded in the areas to the west and south-west of the Mfabeni swamp or in the southern parts of the study area. The techniques used in this study were developed into a water mapping protocol that uses image endmembers and spectral mixture analysis to measure water concentration. / Thesis (M.Sc.)-University of KwaZulu-Natal, Durban, 2006.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 121-123). Also available via the Internet.

No description available.

The Earth Radiation Budget Experiment (ERBE) consists of a suite of three scanning and four nonscanning radiometric instruments on each of three satellites which monitor the solar-reflected and Earth-emitted components of the Earth's radiative energy budget. A numerical model has been formulated to study the dynamic behavior and equivalence of the ERBE scanning thermistor bolometer radiometers. The finite-difference method is applied to the detector of the ERBE scanning radiometer to characterize its thermal and electrical dynamic behavior. The thermal analysis confirms the thermal time constant of the instrument claimed by the vendor. The electrical model reveals that the instrument can be very sensitive to spatial variations of the incident thermal radiation. However, the analysis confirms that the hypothesis of equivalence is justified for viewing typical Earth scenes. / Master of Science

The integration of two Zero-Voltage-Switched Bidirectional Battery Charger Discharger (ZVS-BBCD) units into a space power system is shown. A robust design featuring: four interleaved phases, commandable charge rates, overcurrent protection, overvoltage protection, soft starting, reliable gate drive circuitry, high efficiency, and good dynamics is demonstrated. The ZVS-BBCD is compared to separate hard-switched multimodule charge and discharge units in weight and efficiency and is found to be significantly lighter with comparable losses. The ZVS-BBCD has similar characteristics in discharge and in charge bus regulation modes and allows the use of a common control design for both modes. The two ZVS-BBCDs are integrated into the NASA power system testbed built at the Virginia Power Electronics Center (VPEC) to test their dynamics. The result shows good characteristics including low bus impedance and fast transient response. / Master of Science

From the Proceedings of the 1975 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 11-12, 1975, Tempe, Arizona / The possibility of using imagery from the earth resources technology satellites (ERTS) to monitor changes in areal snow cover in east-central Arizona is examined. Four methods were used in the interpretation of areal snow cover from the ERTS imagery, the densitometer, dot grid, squares grid and projection-planimeter methods providing results of 69, 71, 72 and 74 percent of areal cover respectively. No one method for interpretation of ERTS imagery should be ruled unusable, but any use made of ERTS imagery is dependent upon turn-around time for obtaining the imagery, as snow cover information which cannot be obtained within 24 hours is limited in practical application.