Browsing by Author "Johnson, Daniel"

Now showing 1 - 6 of 6
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    Characterization of lunar crust with moon mineralogy mapper data
    (2015-06-09) Sun, Ying; Lin, Li; Bird, Broxton; Johnson, Daniel; Licht, Kathy; Gilhooly, William P.
    This dissertation has three main focuses: (1) identify the distribution of a new rock type (Mg-spinel lithology) on the Moon and explore the likely petrogenesis of Mg-spinel; (2) investigate the presence of olivine in the crater central peaks and analyze the sources of olivine; (3) determine the compositional variations of lunar crust with depth, and establish a new model to describe the structure of the lunar crust.
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    Improvement and use of radiative transfer models to assess lunar space weathering and mechanisms for swirl formation
    (2015-06-15) Liu, Dawei; Li, Lin; Jacinthe, Pierre-André; Wang, Lixin; Cheng, Ruihua; Johnson, Daniel
    This dissertation focuses on quantification of submicroscopic iron of different sizes, mineral abundance and grain size of lunar soils using Hapke's radiative transfer model. The main objective is to explore implications of these results for assessing the relative importance of solar wind implantation versus micrometeorite impacts for lunar space weathering as well as three hypotheses (solar wind deflection, comet impact and dust transport) for swirl formation on the Moon. Results from this study can help to make connections between ordinary chondritic meteorites and asteroids, and put physical and chemical constraints on heating processes in the early solar system.
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    Interactions Between Social and Environmental Vulnerability
    (Center for Translating Research Into Practice, IU Indianapolis, 2022-04-22) Johnson, Daniel
    In this presentation, Professor Daniel Johnson discusses how he uses predictive analytics to create models that can forecast the effects of extreme events. These models are useful as preparation tools for disaster or as aids to plan for mitigation of potential hazards.
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    Introduction to Daniel Johnson & His Work
    (Center for Translating Research Into Practice, IU Indianapolis, 2022-04) Johnson, Daniel
    Professor Daniel Johnson briefly discusses his translational research that focuses on social and environmental vulnerability and how they inter-relate. When they coincide, there is an increased risk for a disaster. Professor Johnson models these interactions and is working toward creating predictive models that can help increase resilience, prevent disaster or mitigate the effects.
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    Morphological filters in floodplain for DEM-extracted data – using Minimum Bounding Circle & Youden Index
    (2017-06) Jin, Peng; Johnson, Daniel
    Floods are one of the worst disasters in the United States. Each year, the government allocates a tremendous amount of manpower and money on flood prevention initiatives. As the first defense line, levees provide protection from temporary flooding (Makhdoom, 2013). These embankments are broadly classified according to the areas they protect, which could either be urban or agricultural levees within floodplains. In the U.S., most of the levees are handled by government agencies such as the U.S. Army Corps of Engineers and the Federal Emergency Management Services. On the other hand, non-levee embankments created by individual farmers (Olson & Morton, 2013) or naturally formed levee-like structures may not be in the government database. The initial purpose of this research was to assist Polis center on the “Mapping of Non-Levee Embankments in the Indiana” project. The non-levee embankments are not certified or engineered levee-like structures. They, therefore, impose lateral constraints on flood flows, reducing the floodplain storage capacity and increasing the flood velocity. These non-levee embankments can cause stream erosion and downstream flooding. Therefore, it is important to know the locations of these features. The first part of the proposed method adapted the Empirical Bayesian theorem and the low pass filter techniques to extract elevated linear features from LiDAR elevation data – Digital Elevation Model (DEM). The second part of the proposed methods combined the Minimum Bounding Circle (MBC) method and the Youden Index to locate the optimal threshold value that can be used to determine whether the extracted features are levee-like structures. The focus of this study is not only limited to artificial levee-like structures, but also takes the natural levees, or any potential levee-like structures into account because this study assumes all embankments play important roles during flood events.
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    Ryan White: A Geospatial Analysis of his Correspondence
    (2020-05) Shaeffer, Haley Lynn; Johnson, Daniel; Wilson, Jeffrey; Lulla, Vijay
    The letters Ryan White received over the course of his diagnosis, illness, and eventual death show a spatial distribution that reflected the United States’ response to Ryan’s condition. Ryan was diagnosed with AIDS in December of 1984 at the height of the epidemic, and the panic that surrounded it. In 2000, the Children’s Museum of Indianapolis accessioned a selection of letters sent to Ryan White and his mother, from 1980 to 1993. The expanded incorporation of these letters into the museum’s “Power of Children” gallery will introduce museum visitors to the public view on Ryan and the role he played in developing the public perception and awareness of AIDS in the 1980’s. Originally, it was anticipated that the distribution and number of letters Ryan received directly related to the concentration and spread of AIDS cases around the US. This research assumed that the AIDS community would have been more supportive and empathetic of Ryan’s diagnosis, resulting in those populations sending a higher number of letters. This assumption was also informed by the fact that the highest number of AIDS cases were in areas with large populations such as New York City, Los Angeles, and Miami. Yet findings showed relatively few letters were coming from the populated coasts where AIDS was more prevalent, and many more letters than expected came from areas with lower populations across the US. Ryan was one of the first children to go public with his AIDS diagnosis, which sparked strong reactions among people throughout the United States. Ryan’s correspondence and the outpouring of support he received allows insight into the multifaceted reaction to the AIDS crisis, especially from young people. Before Ryan became associated with the AIDS epidemic, this disease was seen primarily as an urban, gay, and drug-user related issue. The goal of this research is to gain further understanding of society’s shifting response to Ryan and AIDS during the 1980’s, by placing these letters in their social and geographic context.