We developed curved spiral antennas for use in underwater (freshwater) communications. Specifically, these antennas will be integrated in so-called mussel backpacks. Backpacks are compact electronics that incorporate sensors and a small radio that operate around 300 MHz. Researchers attach these backpacks in their freshwater mussel related research. The antennas must be small, lightweight, and form-fit the mussel. Additionally, since the mussel orientation is unknown, the antennas must have broad radiation patterns. Further, the electromagnetic environment changes significantly as the mussels burrow into the river bottom. Broadband antennas, such a spiral antennas, will perform better in this instance. While spiral antennas are well established, there has been little work on their performance in freshwater. Additionally, there has been some work on curved spiral antennas, but this work focused on curving in one dimension, namely curving around a cylinder. In this thesis we develop spiral antennas that curve in two dimensions in order to conform the contour of a mussel's shell. Our research has three components, namely (a) an investigation of the relevant theoretical underpinning of spiral antennas, (b) extensive computer simulations using state-of-the art computational electromagnetics (CEM) simulation software, and (c) experimental validation. The experimental validation was performed in a large tank in a laboratory setting. We also validated some designs in a pool (∼300,000 liters of water and ∼410 squared-meter dive pool) with the aid of a certified diver. To use CEM software and perform successful antenna-related experiments require careful attention to many details. The mathematical description of radiation from an antenna, antenna input impedance and so on, is inherently complex. Engineers often make simplifying assumptions such as assuming no reflections, or an isotropic propagation environment, or operation in the antenna far field, and so on. This makes experiments on antennas challenging since it often quite difficult to replicate the simplifying assumptions in an experimental setting. Still, with careful consideration of the important factors and careful experimental design it is possible to perform successful experiments. For example, antenna measurements are often performed in anechoic chambers. For our research we used a large swimming pool to mimic an underwater anechoic chamber. Our CEM simulations and experimental results are in most cases congruent. We are confident that we can design formfitting, compact (spiral) antennas that one could deploy on mussels. This will greatly enhance the mussel backpacks that are used by researchers at the University of Iowa.

During spoken language comprehension, listeners transform continuous acoustic cues into categories (e.g. /b/ and /p/). While longstanding research suggests that phoneme categories are activated in a gradient way, there are also clear individual differences, with more gradient categorization being linked to various communication impairment like dyslexia and specific language impairments (Joanisse, Manis, Keating, & Seidenberg, 2000; López-Zamora, Luque, Álvarez, & Cobos, 2012; Serniclaes, Van Heghe, Mousty, Carré, & Sprenger-Charolles, 2004; Werker & Tees, 1987). Crucially, most studies have used two-alternative forced choice (2AFC) tasks to measure the sharpness of between-category boundaries. Here we propose an alternative paradigm that allows us to measure categorization gradiency in a more direct way. We then use this measure in an individual differences paradigm to: (a) examine the nature of categorization gradiency, (b) explore its links to different aspects of speech perception and other cognitive processes, (c) test different hypotheses about its sources, (d) evaluate its (positive/negative) role in spoken language comprehension, and (e) assess whether it can be modified via training. Our results provide validation for this new method of assessing phoneme categorization gradiency and offer valuable insights into the mechanisms that underlie speech perception.

This dissertation examines various texts that were published in Mexican newspapers during the Revolution (1910-1917) and attempts to determine to what extent the authors of those texts combined journalism with literary creativity as they wrote about the Revolution. The main argument is that many of the texts that appeared in newspapers during the 1910s and covered topics related to the Revolution displayed language, style, and structural elements similar to those found in the official literary narratives of the Mexican Revolution that emerged in the 1920s. The argument is founded on the understanding that sociopolitical and ideological changes in Mexican society, as well as the desire for a new national literature, led intellectuals to re-classify some of the texts that appeared in newspapers in the 1910s from journalism to literary works and adopted their stylistic and thematic elements for the new literature. This is evident in Mariano Azuela’s novel, Los de Abajo and Ricardo Flores Magón’s well-known short stories “Dos revolucionarios” and “El apóstol.” The theoretical framework of this study is informed by the work of Mikhail Bakhtin, Tzvetan Todorov, and Juan Carlos Parazuelos that contend that the value of a narrative changes continuously in response to changes in the society that creates it. Furthermore, the study utilizes Anibal Gonzalez’ notion that there is a gray area between literary narrative and journalism and, therefore, narratives that fall inside the borders of journalism and literature can be classified as one or another or both depending how they interact with social elites, governments, and political affiliations. Finally, this study maintains that journalism, in combination with artistic expression, provided the foundations upon which the later narrative of the Revolution began its development. It was in the realm of journalism that the authors first applied the elements of brevity, direct speech, expressive, yet concise language, episodic narration, and emphasis on action over description and characterization that characterize the literature of the Mexican Revolution.

Garbage landfills are at the heart of debates over sustainable urban development. Landfills are the cheapest waste-disposal method, but have specific environmental problems and are a common target for citizen activism such as environmental justice and Not In My Backyard (NIMBY) protests. As a means of covering up the scars at recently closed landfills, it has been common for cities to redevelop landfills into parks. The ongoing redevelopment projects at New York City's Fresh Kills, Greater Toronto's Keele Valley, and Greater Tel Aviv's Hiriya landfills are uniquely ambitious and large-scale projects, because these three landfills were among the largest in the world at the time each of them closed around the turn of the twenty-first century. These three landfill-park redevelopments are positive projects, but there are more complexities involved than one would find discussed in booster rhetoric such as government press releases, local newspaper descriptions, and even museum exhibitions. The construction of Freshkills Park, North Maple Regional Park, and Ariel Sharon Park does little to address the ongoing waste-disposal policy concerns of New York, Toronto, and Tel Aviv; therefore, the redevelopments have more significance as “symbols” of a poor past policy being replaced by a “progressive” policy for a better future than as actual waste-disposal policies. Artists and landscape architects have created works based on the theme of parkland as a fresh start for these landfills, in gallery and museum exhibitions such as Hiriya in the Museum at the Tel Aviv Museum of Art in 2000 and artwork created by acclaimed environmental artist Mierle Laderman Ukeles for Fresh Kills.

This thesis explores how predictions about upcoming linguistic stimuli are generated during real-time language comprehension in younger and older adults. Previous research has shown humans' ability to use rich contextual information to compute linguistic prediction during real-time language comprehension. Research in the modulating factors of prediction has shown, first, that predictions are informed by our experience with language and second, that these predictions are modulated by cognitive factors such as working memory and processing speed. However, little is known about how these factors interact in aging in which verbal intelligence remains stable or even increases, whereas processing speed, working memory, and inhibitory control decline with age. Experience-driven models of language learning argue that learning occurs across the life span instead of terminating once representations are learned well enough to approximate a stable state. In relation to aging, these models predict that older adults are likely to possess stronger learned associations, such that the predictions they generate during on-line processing may be stronger. At the same time, however, processing speed, working memory, and inhibitory control decline as a function of age, and age-related declines in these processes may reduce the degree to which older adults can predict. Here, I explored the interplay between language and cognitive factors in the generation of predictions and hypothesized that older adults will show stronger predictability effects than younger adults likely because of their language experience. In this thesis, I provide evidence from reading eye-movements, event-related potentials (ERPs), and EEG phase synchronization, for the role of language experience and cognitive decline in prediction in younger and older English speakers. I demonstrated that the eye-movement record is influenced by linguistic factors, which produce greater predictability effects as linguistic experience advances, and cognitive factors, which produce smaller predictability effects as they decline. Similarly, the N400, an ERP response that is modulated by a word's predictability, was also moderated by cognitive factors. Most importantly, older adults were able to use context efficiently to facilitate upcoming words in the ERP study, contrary to younger adults. Further, I provide initial evidence that coherence analysis may be used as a measure of cognitive effort to illustrate the facilitation that prediction confers to language comprehenders. The results indicate that for a comprehensive account of predictive processing research needs to take into account the role of experience acquired through lifetime and the declines that aging brings.

The Luther College Concert Band has enjoyed nearly 150 years of success. International tours, regional tours, concerts, service to the college and recording projects aided the success of this small college band that retained its Lutheran, liberal arts identity. Published documents exist about the Luther College band before 1948 but no comprehensive published documents are available after that time. This essay provides a more complete history of the band since 1948 based upon archival research and interviews with Weston Noble, Fredrick Nyline and Joan deAlbuquerque. The Concert Band started as a student led activity, which set it apart from other university bands of the late nineteenth century that had military connections. The Luther band eventually became an academic area of study and performed solely for campus concerts and on tours. The band took tours to Norway and Europe long before most college bands had touring programs. Later the band toured to Japan, China and Europe and continued regional tours throughout the United States. The Concert Band conductors, particularly the tenures of Carlo Sperati, Weston Noble, Frederick Nyline and Joan deAlbuquerque, helped shape the band program and music department at Luther College. This is a study of their educational philosophies that shaped the band, and the support the program received from the college administration, students and alumni. Also included is information about the Dorian Band Festival hosted by Luther College, works commissioned by the band, a review of works programed by conductors, a listing of recordings by the Luther College Concert Band and biographical information about each conductor.

Social media surveillance is becoming more and more popular. However, current surveillance methods do not utilize well-respected surveys, which were established over many decades in domains outside of computer science. Also the evaluation of the previous social media surveillance is not sufficient, especially for surveillance of happiness on social media. These motivated us to develop a general computational methodology for translating a well-known survey into a social media surveillance strategy. Therefore, traditional surveys could be utilized to broaden social media surveillance. The methodology could bridge domains like psychology and social science with computer science. We use life satisfaction on social media as a case study to illustrate our survey-to-surveillance methodology. We start with a famous life satisfaction survey, expand the survey statements to generate templates. Then we use the templates to build queries in our information retrieval system to retrieve the social media posts which could be considered as valid responses to the original survey. Filters were utilized to boost the performance of the retrieval system of our surveillance method. To evaluate our surveillance method, we developed a novel method to build the gold standard dataset. Instead of evaluating all the data instances like the traditional way, we ask human workers to "find'' as many of the positives as possible in the dataset, the rest are assumed to be negatives. We used the method to build the gold standard dataset for the life satisfaction case study. We also build three more gold standard datasets to further demonstrate the value of our method. Using the life satisfaction gold standard dataset, we show that performance of our surveillance method of life satisfaction outperforms other popular methods (lexicon and machine learning based methods) used by previous researchers. Using our surveillance method of life satisfaction on social media, we did a comprehensive analysis of life satisfaction expressions on Twitter. We not only show the time series, daily and weekly cycle of life satisfaction on social media, but also found the differences in characteristics for users with different life satisfaction expressions. These include psychosocial features such as anxiety, anger and depression. In addition, we present the geographic distribution of life satisfaction, including the life satisfaction across the U.S. and places around the world. This thesis is the first to systematically explore life satisfaction expressions over Twitter. This is done using computational methods that derive from an established survey on life satisfaction.

In order to leverage advances made in body-armor materials, as well as to further the design landscape, considering body armor as a complete human-centric system is becoming more prevalent. This trend necessitates a greater focus on human systems integration (HSI) and human-centric design. Digital human models (DHMs) provide a powerful tool for HSI, but modeling-and-simulation tools, let alone DHMs, have rarely been used with body armor. With respect to analysis, this is changing. New methods for evaluating body armor from a biomechanical perspective have been developed within the SantosTM DHM. It is now possible to import digital models of body-armor systems, place them on an avatar, simulate various tasks (i.e., running, aiming, etc.), and then virtually evaluate the armor's effect on performance, balance, mobility, bulk, etc. However, with respect to design, there are no available simulation tools to help users balance the goals of maximizing mobility and survivability concurrently. In response to these growing needs, there are two new areas of work being proposed and discussed. First, this work leverages a series of new virtual evaluation capabilities for Personal Protective Equipment (PPE) and implements a filter that automatically evaluates and selects from a library of designs the most advantageous PPE system based on user-selected objectives and constraints. Initial tests have shown realistic results with minimal computational demand. Secondly, this thesis proposes a new method for armor-system topology optimization that optimizes not only biomechanical metrics but also external (to the DHM system) metrics from potentially complex injury and protection models. The design variables for this optimization problem represent the position on the body of small body-armor elements. In addition, the existence of each element is modeled as a variable, such that unnecessary elements are determined and removed automatically. This inclusion of location in combination with the traditional existence variable is a novel inclusion to the topology optimization method. Constraints require that no two elements overlap. The objective functions that govern where the armor elements are moved must be general enough to function with any external data, such as survivability. Thus, a novel process has been developed for importing external data points (i.e., stress at points in the body resulting from a blast simulation) and using regression analysis to represent these points analytically. Then, by using sequential quadratic programming for gradient-based optimization, the armor elements are automatically positioned in order to optimize the objective function (i.e., minimize potential injury). This new approach allows any metric to be used in order to determine general body-armor concepts upstream in the design process. This system has the potential to become especially useful when trying to optimize multiple objectives simultaneously, the results of which are not necessarily intuitive. Thus, given a specified amount of material, one can determine where to place it in order to, for example, maximize mobility, maximize survivability, and maximize balance during a series of specified mission-critical tasks. The intent is not necessarily to provide a final design with one "click"; accurately considering all aspects of hard and soft armor is beyond the scope of this work. However, these methods work towards providing a design aid to help steer system concepts. Test cases have been successfully run to maximize coverage of specific external data for internal organs (and thus survivability) and mobility, while minimizing weight. The weight metric has also been successfully used as a constraint in the optimal armor design. In summary, this work provides 1) initial steps towards an automated design tool for body armor, 2) a means for integrating different analysis models, and 3) a unique example of human-in-the-loop analysis and optimization.

The literature on multiculturalism and career counseling (Harro, 2010) has extensively documented the role and influence of environments such as school in the perpetuation of behavioral attitudes like discrimination and racism. Indeed, researchers suggested that early racial discrimination experiences in school may lead African Americans to believe that their education will not benefit them because of the many perceived racial barriers associated with professional careers and employment success (O’Hara et. al., 2011). Due to effects of such experiences, African American students are likely take the path of academic underachievement and low participation in higher education. It is, therefore, of great importance that rehabilitation, school, and college counselors understand the effects of racism on the lives of African Americans. More important, the effects of stress related to the potential experiences of racism on the attainment of a vocational or career goal should be understood. Hence, the purpose of this study was to explore whether there is a relationship between race- related stress and the occupational planning and confidence of African American college students in a predominantly White institution. Results of the present study suggest that participants of the present study are on their way of demonstrating elements of self-efficacy (Lent, Brown, &Hackett, 2000), by the fact that the majority of them have already selected a major area of study. This may suggest that the process of career selection is well on its way from career selection to career confidence or implementation. It is noteworthy the number of majors selected and how many of them are in careers of high demand like engineering. Results from the present study also suggest that participants perceive race related stress variables in the domains of cultural and institutional racism, as having a moderate association with their career importance. This may be interpreted as African American students who participated on this study perceive that stress experienced due to issues related to cultural and organizational racism are an important factor that should be considered when choosing a career. Data also suggests that race-related stress does not affect the career confidence of African American students who participated on this study. As a group, participants of this study do not seem prepared to or have made a plan for achieving a career path as indicated by the lower scores and negative correlations in the Career Planning area. This is an important finding and although out of the scope of this study, lack of access to resources like career counseling or guidance may be an indicator or potential explanation for this finding. Although sample size was one of the limitations of this study, future research should try to replicate this study and further explore the potential relationship between experiencing race-related stress and the selection and implementation of a career plan.

The Trust Region Subproblem (TRS), which minimizes a nonconvex quadratic function over the unit ball, is an important subproblem in trust region methods for nonlinear optimization. Even though TRS is a nonconvex problem, it can be solved in polynomial time using, for example, a semidefinite programming (SDP) relaxation. Different variants of TRS have been considered from both theoretical and practical perspectives. In this thesis, we study three variants of TRS and their SDP/conic relaxations. We first study an extended trust region subproblem (eTRS) in which the trust region equals the intersection of the unit ball with M linear cuts. When m = 0, when m = 1, or when m = 2 and the linear cuts are parallel, it is known that the eTRS optimal value equals the optimal value of a particular conic relaxation, which is solvable in polynomial time. However, it is also known that, when m ≥2 and at least two of the linear cuts intersect within the ball, i.e., some feasible point of the eTRS satisfies both linear constraints at equality, then the same conic relaxation may admit a gap with eTRS. We show that the conic relaxation admits no gap for arbitrary M as long as the linear cuts are non-intersecting. We then extend our result to a more general setting. We study an eTRS in which a quadratic function is minimized over a structured nonconvex feasible region: the unit ball with M linear cuts and R hollows. In the special case when m = 0 and r = 1, it is known that the eTRS has a tight polynomial-time solvable conic relaxation. We show that a certain conic relaxation is also tight for general R and M as long as the cuts and hollows satisfy some non-intersecting assumptions that generalize the previous paragraph. Finally, intersecting the feasible region of TRS with a second ellipsoid results in the two-trust-region subproblem (TTRS). Even though TTRS can also be solved in polynomial-time, existing approaches do not provide a concise conic relaxation. We investigate the use of conic relaxation for TTRS. Starting from the basic SDP relaxation of TTRS, which admits a gap, recent research has tightened the basic relaxation using valid second-order-cone (SOC) inequalities. For the special case of TTRS in dimension n=2, we fully characterize the remaining valid inequalities, which can be viewed as strengthened versions of the SOC inequalities just mentioned. We also demonstrate that these valid inequalities can be used computationally even when n > 2 to solve TTRS instances that were previously unsolved using techniques of conic relaxation.