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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.
1

Interpreting radar scattering : circular-polarization perspectives from three terrestrial planets

Haldemann, Albert Frank Christian. Muhleman, Duane O. Murray, Bruce C. January 1997 (has links)
Thesis (Ph.D.) -- California Institute of Technology, 1997, UM #9800358. / Advisor names found in the Acknowledgments pages of the thesis. Title from home page (viewed 04/30/10). Includes bibliographic references.
2

Remote sensing analysis of cratered surfaces Mars landing hazard assessment, comparison to terrestrial crater analogs, and Mars crater dating models /

Chee, Yenlai, January 2007 (has links)
Thesis (M.S.)--University of Texas at El Paso, 2007. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.
3

Seaward Landward : Investigations on the archaeological source value of the landing site category in the Baltic Sea region

Ilves, Kristin January 2012 (has links)
There is a tendency in archaeology dealing with watercraft landing sites in a wider context to assume a direct relationship between sites in coastal and shore-bound areas and the practise of landing, without any deeper practical or theoretical exploration of the reality of any such relationship. This problem has its origins in the poor archaeological and conceptual definitions of watercraft landing sites obstructing any real understanding of the role of these sites in the maritime cultural landscape. Landing sites are taken for granted and they are undervalued as an archaeological source of explanation; notwithstanding, the concept of the landing site is readily used in archaeology in order to underpin archaeological interpretations on the maritime activities of past societies. In order to break away from the simplified understandings of past water-bound strategies based on the undefined concept of the landing site, this dissertation suggests a definition of watercraft landing sites in a wider social sense as water-bound contact zones; places of social interaction that can be archaeologically identified and investigated. This perspective integrates the understanding of the intentional character of human activity related to watercraft landing with the remaining archaeological traces. Archaeological definitions of landing sites that can be tested against the archaeological data are provided, and thereby, the dissertation contributes with the possibility to archaeologically evaluate and approach the social function of watercraft landing sites. This dissertation demonstrates that there can be an archaeology of landing sites.
4

Urban Air Mobility (UAM) Landing Site Feasibility Analysis: A Multi-Attribute Decision Making Approach

Tarafdar, Sayantan 29 January 2020 (has links)
This thesis presents methods to place landing sites for the Urban Air Mobility (UAM) concept. The analysis shows an integrated approach to establish UAM landing site requirements, place landing sites based on predicted demand, and estimate the costs associated with UAM landing sites. This thesis also makes estimates of fares associated with UAM operations. The methods presented are applied to three large urban centers in the United States. The analysis assumes an all-electric, advanced multi-rotor aircraft with autonomous navigational and Vertical Takeoff and Landing (VTOL) capabilities to estimate UAM landing site requirements. The thesis presents the land area requirements of UAM landing sites using Federal Aviation Administration heliport design criteria considering ground-taxi configurations. The analysis performed employs a UAM vehicle with an equivalent Rotor Diameter (RD) of 43 feet. In this thesis, UAM demand is estimated using a mode choice model developed in a companion study (UAM Scenario Analysis). The methodology to locate UAM landing sites includes splitting and consolidation of UAM landing sites considering the Zillow Transaction and Assessment Dataset (ZTRAX) to introduce land-use size and cost constraints. The sites are split using a K-Means clustering method and are consolidated using a simple center of mass approach where the demand of each landing site is analogous to mass. The results presented in this thesis apply to 75 and 200 landing sites in each region and assume passenger Cost-Per-Mile (CPM) of $1.20 and $1.80, respectively. This thesis presents a comparative study on how the availability of land affects the splitting, consolidation, and relocation of UAM landing sites for each region, the number of landing sites, and the cost per passenger-mile. / Master of Science / This thesis aims at the landing sites for the Urban Air Mobility (UAM) concept for commuting passengers in Northern California (17 counties), Southern California (9 counties), and Dallas-Fort Worth (12 counties) region. The aircraft for this service is designed to be an all-electric advanced multi-rotor aircraft with autonomous navigational and Vertical Takeoff and Landing (VTOL) capabilities. The commuting trips considered is focused on passengers traveling to work from home and back. This thesis presents the land area requirements of these landing sites, which are calculated from the Federal Aviation Administration's (FAA) Advisory Circular 150/5390-2C using ground-taxi configuration for a typical representative aircraft of an equivalent rotor diameter (RD) of 43 feet. The landing sites are then split into smaller sites and consolidated into larger sites. This thesis also presents a list of plots of land located within the 0.5 statute-mile boundaries of the landing sites for relocation. This entire analysis is based on the availability of land from the Zillow Transaction and Assessment Dataset (ZTRAX). The results presented in this thesis are for 75 and 200 landing sites set in the study area for a passenger Cost-Per-Mile (CPM) of $1.2 and $1.8, respectively. The results show how the availability of land changes for different CPM for a set of landing sites and affects the splitting, consolidation, and relocation of landing sites for each region. In the end, the thesis presents conclusions and recommendations unique to each region.

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