Master of Arts, University of Toledo, 2004, Geography and Planning

Growing freight has been a major concern for the transportation planning community. Increasing freight movements by all modes of transportation across the nations has lead to congestion and inadequate infrastructure. There is a rising need for Internet based freight management spatial decision support systems (SDSS) exploiting the latest Geographical Information Systems (GIS) and Remote Sensing (RS) technologies that can assist the transportation planning community in making informed decisions about freight related issues consisting of congestion, demand and capacity. The system being an online or web based system has the advantage of being accessed from anywhere thus making it an easy tool for sharing information across different regions. This can also be utilized for asset management, data dissemination and to model alternative freight management plans and “what if?” scenarios. There is no established framework to date for the development of such systems. A pragmatic approach is taken in this study to design and develop a conceptual framework for an Internet or web based freight management spatial decision support system (SDSS). Different components, features and technology that are required to create such systems were discussed in detail along with a variety of development and implementation strategies. The developed framework was utilized in creating a freight management SDSS for the Upper Midwest Freight Corridor Study currently underway at The University of Toledo encompassing the states in the Midwest. This has given an opportunity to look at the feasibility of implementing such systems and the difficulties faced. The freight management SDSS is currently online and is anticipated to be used by Department of Transportation officials, urban and transportation planners and homeland security officials in making informed decisions. Thus, the conceptual framework developed in this study can be used as the rudimentary framework for creating a robust freight manageme (open full item for complete abstract)

Committee: Peter Lindquist (Advisor) Subjects:

Master of Science, The Ohio State University, 2021, Mechanical Engineering

Spectroscopy is one of the more common scientific practices in the realm of astronomy because it allows astronomers to deduce properties of stars, galaxies, and other celestial objects, such as mass, temperature, chemical composition, redshift, presence of orbiting bodies, and more. Specifically, multi-object spectroscopy has become popular in ground-based astronomy for accumulating large quantities of data. This data is collected with optical fibers located at a telescope's focal plane that then send the collected light to instruments called spectrographs for analysis. Up until recently, these fibers were always fixed in stationary configurations. Now, the astronomy community has begun working with fiber positioning robots that can dynamically and automatically reconfigure the fibers. This functionality allows for more observing time, and thus more data collected, each night that previously would have been spent manually reconfiguring fibers. One such project employing this new strategy is the Sloan Digital Sky Survey (SDSS-V). A lot of work goes into preparing instruments with robotic fiber positioners, and a great deal of effort is put in to retire as much risk as possible before delivery to observatories. This thesis discusses the development and implementation of an optical measurement system that serves to measure the positional accuracy performance of the fiber robots and that is used to develop and exercise the software package to be used with the Focal Plane System instruments of SDSS-V prior to arrival on-site. Specifically, the fixed fiber-illuminated fiducial metrology, opto-mechanical design of the measurement system, and the development of the optical transform to be used to evaluate robot positional accuracy is detailed herein. This lab-based pre-commissioning strategy is unique to the subset of these instruments with connectorized fibers since they can operate without being interfaced with a telescope and spectrograph(s). From a software (open full item for complete abstract)

Committee: Richard Pogge (Committee Member); Giorgio Rizzoni (Advisor) Subjects: Astronomy; Mechanical Engineering; Optics

Doctor of Philosophy, The Ohio State University, 2023, Physics

Correlations in and with the flux transmission of the Lyman-alpha (LyA) forest in the spectra of high-redshift quasars are powerful cosmological tools, yet these measurements can be compromised if the intrinsic quasar continuum is significantly uncertain. One particularly problematic case is broad absorption line (BAL) quasars, which exhibit blueshifted absorption associated with many spectral features that are consistent with outflows of up to ~0.1c. As these absorption features can both fall in the forest region and be difficult to distinguish from LyA absorption, cosmological analyses eliminate the ~12 - 16% of quasars that exhibit BALs. This work explores an alternate approach that includes BALs in the LyA auto correlation function, with the exception of the expected locations of the BAL absorption troughs. This procedure is tested on both the SDSS DR14 and DESI Year 1 LyA catalogs, using the reduction of error on the autocorrelations as a metric for success. The masking procedure returns over 95% of the pathlength that is lost by the exclusion of BALs, as well as increases the density of sightlines. It shows that including BAL quasars reduces the fractional uncertainty in the covariance matrix and correlation function by 12% on SDSS DR14 and 20% on DESI Year 1. Furthermore, it does not significantly change the shape of the correlation function relative to analyses that exclude BAL quasars. It also evaluates different definitions of BALs, masking strategies, and potential differences in the quasar continuum in the forest region for BALs with different amounts of absorption.

Committee: Paul Martini (Advisor); Linda Carpenter (Committee Member); Chris Hirata (Committee Member); Klaus Honscheid (Advisor) Subjects: Astronomy; Physics

BA, Oberlin College, 2022, Physics and Astronomy

In this thesis, I introduce a method to identify and characterize the effects of active galactic nuclei (AGN) on the spectra of nearby star-forming regions. I analyze spatially-resolved areas of galaxies called “spaxels” within Data Release 15 of the Sloan Digital Sky Survey (SDSS) with the goal of locating those which are physically close to AGN. I find those spaxels with calculated metallicities which lie adjacent to AGN-flagged spaxels and characterize their metallicity values relative to the spaxels which are not adjacent to AGN-flagged spaxels, using a total of 11 separate metallicity calibrations. I find that the current methods to mask AGN-influenced regions for large-scale investigation are, in general, robust, as the largest median deviation between metallicities in border spaxels and those in non-border spaxels is 0.0467 dex. The largest mean difference in metallicity between border and non-border spaxels is 0.0522 dex with a standard deviation of 0.0590 dex. However, on a spaxel-by spaxel basis, I find that the differences in metallicity between border spaxels and non-border spaxels can be as large as 0.9350 dex. These results are concerning for spaxel-by-spaxel analysis, and indicate the need for an improved masking process in the future.

Committee: Jillian Scudder (Advisor) Subjects: Astronomy; Astrophysics; Physics