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Design and integration of a low cost, size, weight, and power vertical-pointing synthetic aperture radar
Get PDFIn modern radar applications, cost, size, weight, and power (C-SWaP) are increasingly
becoming critical factors in the design process. For use cases specifically
in airborne radio frequency (RF) imaging, there is a key opportunity for improvement
in C-SWaP. Typical synthetic aperture radar (SAR) systems consist of
aircraft-mounted electronics utilizing an inertial measurement unit (IMU) to provide
accurate and precise location information in order to form the synthetic aperture
as the aircraft is in flight. Most current SAR applications do not have strict
requirements for SWaP since an airframe is capable of handling a sizable amount
of weight. With the increased proliferation of smaller airborne vehicles and drones,
there is a demand for low C-SWaP radar systems capable of imaging.
In this work, the design and operation of a radar system is discussed. First, basic
system requirements including a basic link-budget analysis, and system architecture
with low C-SWaP are explored. The analog hardware is then discussed and a RF
chain analysis is conducted. The capabilities of the backend module used to capture
the data and the IMU used to obtain positional information are then briefly
discussed. A basic analysis of the signal processing for SAR is conducted. Finally,
results of airborne SAR imaging conducted utilizing the radar system described
above are discussed. The system is used in a vertical-SAR (VSAR) configuration
as a radar-altimeter to produce an elevation profile of the ground covered by the
aircraft
Some novel approaches to economic problems
Get PDFIn chapter 1, I investigate the role of social connections in the formation of political coalitions utilizing the county-to-county Social Connectedness Index (SCI) from Facebook. Using a generalized fixed effects model I estimate the impact of the SCI-weighted network vote margin on focal county vote margins. Democrat-leaning counties (above-median Democrat-net-Republican percentage) respond robustly to the influence of their social network in all years examined. Republican-leaning counties accelerated coalition formation in years after the 2012 election. Since voting for the US president happens at the same time in all counties, I also use a 2SLS analysis to deal with the endogeneity that stems from this simultaneous action. I construct the instrument for the endogenous network-wide vote margin variable by utilizing the network structure of the dataset. The empirical analysis in this paper confirms a high and growing level of political polarization in the US.
Chapter 2 creates a new measure of social capital that combines bridging and bonding social capital. New data from the Facebook user network makes this possible. I use the new measure to reassess the role of social capital on a variety of outcomes previously studied in the literature. I use the network topology of social connections and within-county associational membership levels to measure county-level social capital. This measure allows one to combine two different types of measures into a comprehensive one. Since bonding and bridging social capital are by nature different, the ability to measure these two values from different sources and then combine them improves my measure of social capital over previous ones. Results show that my measure is a superior predictor of a variety of social and economic outcomes.
Chapter 3 is coauthored with Cheng Ma. In chapter 3, we test the effect of additional children in a family on health and educational outcomes. Estimating this effect is complicated by the endogeneity of family size. We use the variation in the severity of the effect of the one-child-policy in China to extract exogenous variation from the China Health and Nutrition Survey in the same country. After finding a negative effect of family size on health and educational outcomes of children we use a newly developed machine learning approach. Generalized random forests allows us to look at the heterogeneity in treatment effects in the quantity-quality trade-off. We find robust negative treatment effects of additional children on health outcomes but only mild effects on educational attainment. The machine learning algorithm finds mother's age and parent's education level play a large role in the negative quantity-quality trade-off. Pinpointing the factors that exacerbate the negative effect of additional children on child quality can aid future policy decisions
The Roles of Bedrock Mortars in Rockshelters of Eastern Oklahoma
Get PDFRockshelters form an important part of the archaeological landscape. Rockshelters served a number of purposes, and in pursuit of those purposes they could be altered or adjusted. A prominent example of these rockshelter alterations is the presence of bedrock mortars, which consist of grinding and pounding surfaces deliberately carved into bedrock floors or large, immobile boulders.
The functions of these bedrock mortars have long been assumed to be purely economic, only used for processing food plants. However, recent research has broadened the scope of bedrock mortars to investigate larger connotations of their contributions to the archaeological record.
This thesis compares the combined implications of rockshelters and bedrock mortars to assess possible uses in Eastern Oklahoma. Based on the characteristics recorded in existing site files and survey reports, I propose that bedrock mortars in the study area were small-scale, specialized features placed in Pennsylvanian sandstone that were designed to efficiently process local environmental resources, and that they were potentially places of small-scale interpersonal communication and cultural transmission, and most likely used by women. Evidence of these bedrock mortar rockshelters having intense symbological or spiritual associations is lacking, but not impossible.
I also propose future directions of research, to raise awareness of their significance to the archaeological record, and to expand the study of these features into the Midwest
Limitations and evaluation of the linear assumption on antenna design
Get PDFA common assumption made by antenna engineers is to consider a system to be linear and time-invariant (LTI). This assumption is incredibly powerful and has enabled a century of advancements, but consequently has perhaps made electrical engineering too reliant upon it. There are multiple cases of fundamental limits being circumvented by including non-LTI devices and analysis. Additionally, there are limitations of some systems that are not well understood or avoided as a subject due to their non-LTI nature. Exotic antennas are attractive to complex, modern communication systems, but they are effectively useless if they cannot be deployed in practical settings after design sequences - as is sometimes the case in the presence of potentially nonlinear devices. Therefore, this work provides insight into the limitations of non-LTI analysis for antenna engineering and the trade-offs of some antennas that are erroneously capable of nonlinear behavior. Doing so will help shed light on the ramifications of casually making the LTI assumption and methods to better understand such antennas
The girl with the agate eyes: the life and times of Mattie Howard
Get PDFThis thesis studies the life of Martha Alice “Mattie” Howard, a forgotten figure in both the early 20th-century criminal underworld and the evangelical circuit of 1930s and 1940s America. Straddling the line between social deviant and moral exemplar, Mattie’s story is one of constant reinvention and narrative building. When she was accused of murder in Kansas City, Missouri, the local and, eventually, national press painted her as a nearly supernatural force for evil. Nearly twenty years later, Mattie published an autobiography in which she directly attacked the narratives of the newspapers and sought to portray herself as an inherently moral and good woman who had been falsely persecuted. Coupling this narrative shift alongside her conversion to evangelical Christianity and new career as a traveling minister, her reinvention as a woman of God was taken at face value and the direr accusations against her were conveniently forgotten. A study of Mattie’s life sheds light on several different types of history, from gender to criminal to religious, and provides a unique portrait of a woman who appeared on both sides of the respectability divid
Prison Valley, U.S.A.: The Making of a Carceral Capital, 1861-1994
Get PDFThe history of incarceration in Colorado from the birth of the territory in the 1860s through the 1990s is a history of continuity. Coloradans invoked the criminal legal system as a symbol of the state’s legitimate, effective governing powers and to define freedom as a product of race and class. The heart of Colorado’s prison system lies in Fremont County, where 20% of its residents are captive in the county’s nine state and four federal prisons. The county’s economy, culture, and politics revolve around the practice and idea of incarceration. Since Fremont County’s leaders pursued its first prison in the 1860s, local stakeholders have sought out and fought for carceral infrastructure. The history of incarceration in Colorado demonstrates the continuous presence of convict leasing, Jim Crow, and mass incarceration. Fremont County displays such recent developments as part of a longer, sustained history of carceral development in the United States, showing the punitive orientation that long undergirded America’s political and economic systems.
The persistent notion that freedom requires unfreedom justified carceral development as a social welfare solution serving both racialized criminalized communities and economically depressed spaces. Throughout this long history, the carceral state’s fundamental logics remained the same: that incarceration was a positive good that protected the free world and supported prison communities; and second, incarcerated people must provide labor for the state to offset the costs of incarceration and make the institution self-sufficient.
Despite the continuities in logics and practices, to be sure, the politics and processes of incarceration changed over time, especially as incarcerated people challenged the carceral state in new ways. Protest against the carceral state has been one of its persistent features. Incarcerated people and their allies protested in sanctioned and unsanctioned ways. Sanctioned protests, such as through the courts, regenerated the carceral state’s legitimacy by proving that it could reform itself without external oversight. Unsanctioned protests, such as work stoppages and escapes, provoked the state to develop new modes and architectures of incarceration.
In the 1860s, Fremont County and Colorado Territory leaders pursued a prison to prove to the country that they deserved statehood. An effective criminal legal system, they argued, demonstrated effective governance that protected its citizens. Over the state’s next 150 years, the notion that the state’s authority could be built and regenerated in strong criminal legal system that evolved continuously persisted. Colorado and the United States continued to expand its prison infrastructure—a women’s facility in 1935, a medium- and maximum-security prison in the 1950s, three new state prisons in the 1960s, a new Colorado prison industries program in the 1970s, four new state prisons in the 1980s, four federal prisons in the 1990s, and two new state prisons in the 1990s. This sustained carceral development represents a society dependent on punishment. Prisons, exemplified by those in Colorado, are a key to a society convinced that freedom for some requires the unfreedom of others
