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Showing 161–200 of 2,281,243 items
  • Test Generation and Evaluation for Bridging Faults in CMOS VLSI Circuits
    Scholarship
    Creator
    Lee, Terry Ping-Chung
  • Information Structures in Nash and Leader-Follower Strategies
    Scholarship
    Creator
    Salman, Mutasim A.
  • State Estimation for Linear Systems Driven Simultaneously by Wiener and Poisson Processes
    Scholarship
    Creator
    Au, Samuel Poriza
    Description
    Coordinated Science Laboratory changed its name from Control Systems Laboratory
  • Estimation for Uncertain Linear Systems with Jump Parameters
    Scholarship
    Creator
    Tugnait, Jitendra Kumar
    Description
    Coordinated Science Laboratory changed its name from Control Systems Laboratory
  • A Simulation Program with Latency Exploitation and Node Tearing
    Scholarship
    Creator
    Yu, Tat Kwan Edgar
    Description
    Coordinated Science Laboratory was formerly known as Control Systems Laboratory
  • Sensitivity of Lower Order Observers
    Scholarship
    Creator
    De Sa, Erwin
    Description
    Coordinated Science Laboratory was formerly known as Control Systems Laboratory
  • Exploring Design Configurations of System Models: From Simultaneous Simulation to Search Heuristics
    Scholarship
    Creator
    Gaonkar, Shravan
  • Performance Analysis of Garbage Collection and Dynamic Reordering in a Lisp System
    Scholarship
    Creator
    Llames, Rene Lim
  • Parallel Input/Output Architectures for Multiprocessors
    Scholarship
    Creator
    Annapareddy, Narasimha Reddy L.
  • Heavy-metal-free colloidal nanocrystal heterostructures – synthetic chemistry and growth mechanisms
    Scholarship
    Creator
    Zhai, You
    Description
    Building heterostructures of colloidal nanocrystals by bringing different components into contact can improve existing or impart novel properties, which enables applications as light emitters in already-commercialized and near-future products. However, the majority of the research has been based on compositions with heavy metals (e.g., cadmium or lead) posing toxicity concerns to the consumers. Therefore, a better understanding of the synthetic chemistry and the growth mechanisms for heavy-metal-free nanocrystal heterostructures is critical before their commercialization potential becomes reality. Here, we have developed novel synthetic strategies to achieve the anisotropic growth of colloidal nanocrystals and the introduction of multiple components with tunability of their positions in the heterostructures, as well as to improve the photoluminescence quantum yield (PL QY) of nanocrystals. We first examine how different Cu precursors in the synthesis of colloidal copper sulfide (Cu2-xS) nanocrystals affect the resulting shape and phase. Decreasing aspect ratio in 1D nanorods (eventually transitioning to 2D nanodisks) observed is consistent with the expected effects of decreasing Cu precursor reactivity. Nanorods are predominantly chalcocite at the early stages of growth but a phase transition to djurleite occurs accompanied by a change in tip faceting upon further growth. In contrast, nanodisks appear in the djurleite phase early on and remain so upon continued growth. Secondly, the high copper vacancy density and the high cation mobility in the Cu2-xS nanorods favor cation exchange, and the remaining Cu2-xS after partial cation exchange can serve as the catalyst for the subsequent solution-liquid-solid (SLS)-like growth. The interplay between cation exchange and SLS-like growth leads to tapered rod-rod, body/tail, or barbell-like Cu2-xS/ZnS heterostructures, which can be controlled by the Zn precursor and ligand choice. Finally, using a similar procedure, spontaneous multiple segment formation has been achieved in Cu2-xS/CuGaS2 heterostructured nanorods for the first time. Large strain due to lattice mismatch (-7.4% in the axial direction and -10.6% in the other direction) is responsible, because such segmentation is absent in Cu2-xS/CuInS2 heterostructured nanorods with a smaller mismatch (-4.3% in the axial direction and -6.5% in the other direction). More importantly, ligands with a large steric hindrance are critical to the multiple segment formation, which pack less densely on the surface and enables nucleation in the middle of the nanorods. In contrast, linear ligands provide better surface protection and the new components tend to form at the tips of the nanorods where the ligand packing density is relatively low. In addition to Cu2-xS-based anisotropic heterostructures, we have also explored how to enhance the PL QY for heavy-metal-free color-center (manganese)-doped nanocrystals and ZnTe-based core/shell nanocrystals with spherical shapes. Annealing or growth at high temperatures for an extended period of time is considered detrimental for the synthesis of high-quality Mn-doped II-VI semiconductor nanocrystals, which can lead to the broadening of size distribution and, more importantly, to the loss of dopants. However, ripening can be beneficial to doping in a simple heat-up approach, where high dopant concentrations can be achieved. Smaller nanocrystals in a reaction batch, on average, exhibit higher undesirable band edge PL and lower desirable dopant PL. The optimization of dopant loss and the removal of such smaller undesirable nanocrystals through Ostwald ripening along with surface exchange/passivation to remove Mn clustering lead to high Mn PL QYs (45 to 55 %) for ZnSxSe1-x, ZnS, CdS, and CdSxSe1-x host nanocrystals. Similar with the synthetic optimization for doped nanocrystals, surface passivation by a high-quality ZnSe shell and a cation-rich surface by Zn-cation treatment enable a high PL QY (~40%) for ZnTe-based nanocrystals. The highly reactive selenium powder provides better synthetic control of the ZnSe shell. In addition, highly reductive ligand (diphenylphosphine) can further increase the PL QY presumably by filling surface electron trap states.
  • Understanding television demand for National Football League: factors influencing sport demand across gender and age...
    Scholarship
    Creator
    Xu, Jie
    Description
    As viewership of sports have become an indispensable part of American culture, understanding the demand for spectator sports has become an essential branch of economic study. Gender and age are two vital demographics that have been addressed in many prior sport management studies. Although previous studies in sport participation reveal the importance of demographics in evaluating sport demand (e.g., Lera-Lopez & Rapun-Garate, 2007; Robinson & Trail, 2005), there are few studies regarding gender differences in sport economics. The purpose of this study is to understand the factors influencing sport demand trends within specific gender and age groups. The main research questions in this study are: “Is there a difference between male and female fans’ sport demand?” “Is there a difference between the demand of younger and older fans?” and “What factors mediate sport demand for different gender and age groups?” Among the mediating factors, this study focused particularly on outcome uncertainty. In this study, based on demand theory in economics, a hedonic model for each demographic (i.e. gender and age) group was developed. The model in this study followed Borland and Macdonald’s (2003) conceptual framework for professional sporting contests. The determinants included four main economic factors, consumer preferences, timing of contest, and characteristics of sport contests. Using the setting of National Football League (NFL) regular season games, telecast demand for each demographic group was estimated. Then comparisons of male and female television viewers, young and adult viewers, and young and older viewers were conducted. Among the meaningful findings, most determinants exerted statistically significant influences on both male and female viewers’ demand. Monday Night Football games and several month dummy variables were not significant in the gender-differentiated demand model. Surprisingly, outcome uncertainty did not play a significant role in either gender’s demand estimations. The comparison study revealed that there are more similarities than differences in the predictors of female and male viewership. In terms of gender-differentiated sport demand, there are several determinants that uniquely impacted female and male broadcast demand. For example, only one month dummy (which indicates the game was played in December and January) and YearTrend variable (Which indicates the season that NFL game was played) were found having significant impacts in female broadcast viewers. Meaningful determinants include the market’s television population size and local team quality, which were two variables that showed statistically significant difference across gender comparisons. With regard to age group differences, most determinants were also found statistically significant in three age groups’ broadcast viewers (i.e., youth, all adults, and older viewers). Moreover, Monday Night Football games and most month-based dummy variables were not significant influences on either youth or all adults’ demand, but those variables played significant roles in older viewers’ demand estimation. The lowest explained variance among these three estimations is the youth cohort’s demand model (45.6%), which means young people’s broadcast demand may be difficult to estimate and in need of further study. Three variables demonstrated significant differences across age groups. Those three salient determinants of age-based trends are local market’s average income, local team tenure and local team quality. One additional variable showed distinct impact on the viewership of youth versus older adults—early-season versus late-season broadcasts. It was found that there were fewer older adult viewers for early season when comparing with late-season games. An unexpected finding was that outcome uncertainty did not play a role in differences between male and female viewership, nor between youth and adult viewers or youth and older adult viewers. The main contribution of this study is developing economic framework for sport estimation delineated by gender and age groups. Moreover, this study’s in-depth view on how differences in determinants impact each group’s demand will improve the understanding of various cohorts’ sports consumption patterns. Empirically, the results of this study also provide the trends of sport consumption based on demographic groups, which would help league to know well of its customers and contribute to making marketing strategies.
  • Incentives in the classroom: performance-based compensation implementation and impact in high performing schools in...
    Scholarship
    Creator
    La Londe, Priya Goel
    Description
    Performance-based compensation is gaining traction in the education systems of countries that lead in the world economy and in comparative international assessments of student achievement. Longstanding and contemporary debates in educational policy and research question the potential of this incentivist policy to improve teaching. Some scholars warn that decades of experimental research have found bonuses yield little or no improvement in various measures of teaching quality and student achievement. Yet, policymakers and performance-pay advocates maintain that financial bonuses will lead to better teaching, student learning, and educational markets. As PBC persists, we remain unaware of how financial bonuses are enacted and shape teaching. To better understand how financial bonuses shape teaching, recent qualitative research has investigated exactly how performance-based compensation unfolds inside of complex school settings. Building on this emerging scholarship, this research examined the implementation of merit pay and its effects on teaching from the perspectives of teachers at School M1, a high performing elementary school in Shanghai. Those who aspire for high ranks in comparative international assessments and other proxies of global economic leadership are turning to regions such as Shanghai for lessons on “what works.” Shanghai thus provided the opportunity to investigate incentivism in a system that has gained global influence yet whose policies and corresponding practices remain understudied. A principal and 20 teachers were interviewed, and a range of policy documents were collected in This qualitative case study. Data were coded according to theory on incentivism, policy enactment, and teacher development. Responses were then further analyzed to determine recurring themes and patterns. I find that state and national policymakers and the M1 Principal intended for PBC to improve teaching quality. However, the M1 teacher participants perceived bonuses were intended to augment base pay, compensate teachers for their existing effort, and to provoke teachers to exert additional effort. Teachers had little understanding of merit pay implementation processes. While merit pay did not erode teacher relationships, and norms of respect and deference to authority guided teachers’ silence on and acceptance of the policy and shaped their participation in policy enactment. They perceived high expectancy, low instrumentality and valence, and they held mixed views on fairness. The majority of teachers suggested their sense of motivation and self-efficacy was driven by a sense of personal responsibility for collective good and by public displays of recognition from their peers and superiors. Teachers suggested that social relationships, professional community, and trust were more efficacious ways to get to improved teacher quality. Overall, teachers perceived bonuses neither inspired instructional improvement compelled their low performing peers to leave the school or the profession. Advocates suggest bonuses motivate educators to behave in desirable ways, incentivize strong teachers to join and stay in the workforce, and force weak teachers to exit. While compelling, this lens ignores how financial incentives operate in the cultural foundations of schools. Additionally, teacher perceptions of bonuses bear directly upon how bonuses are levied in schools. To assess the efficacy of PBC as a school improvement mechanism, this research offers a sorely needed school-level investigation of PBC that explores the perspectives of teachers and is founded in sociocultural lenses on school improvement. In doing so, this research builds on an emerging body of qualitative research that helps assess the prevailing hypothesis that there is a neat relationship between an incentive, teacher practice, and student learning.
  • “We must keep reaching across the table and feed each other” life stories of Black women in academic leadership roles in...
    Scholarship
    Creator
    McMillion, Desiree Y.
    Description
    “Black women have obtained leadership position as administrators at higher education institutions. While previous research has demonstrated that obtaining leadership positions is problematic for Black women, little research focuses solely on the plight and personal agency of Black women administrators”. While there exists a substantial body of literature devoted to examining the ways in which sexism, Anti-Black racism, gender and class inequality shape and limit leadership opportunities for Black women in education, few studies have focused on the personal agency of these women and how it influences their actions with regard to leadership within higher education. This phenomenological study examines the lived experiences of Black women in administrative leadership roles in higher education at predominantly white institutions and how race and gender intersect, and contribute to their career trajectories in academia.
  • The influence of individual and organizational variables on informal learning among nurses in Korean hospitals
    Scholarship
    Creator
    Lee, Da Ye
    Description
    Health professionals work in knowledge organizations where human capital is the most important asset. The development of quality and efficiency in treatment and care depends mainly on the ability of staff to use, refine and learn new knowledge and skills. Learning in hospital settings is both formal and informal. Marsick (2006) suggests that approximately 80 percent of skills in hospital work are learned in informal, day-to-day interaction. Formal learning has been extensively studied, and there are many reports on the design and outcomes of formal continuing professional development for nurses and physicians; however, there are few studies exploring informal learning by nurses. Therefore, the present study identifies the hierarchical linear relationship among informal learning, individual and organizational variables of nurses in hospitals, to empirically demonstrate the personal and organizational factors influencing informal learning while considering the different organizational scales and cultures between hospitals and to determine the extent to which individual nurses engage in informal learning. Regarding individual and organizational level variables, a questionnaire assessed Informal Workplace Learning Outcomes, individual level variables (Task Variety, Task Significance, Friendship with Other Nurses and Learning Motivation), and organizational level variables (Empowerment, Leadership, Perception of Team’s Support, and Openness of Team’s Communication). To collect the data for this study, approximately 2,300 nurses working at 5 medium-to-large-sized Korean hospitals with more than 250 beds were invited to complete the questionnaire survey online. Overall, 218 complete responses were analyzed using One-Way ANOVA and hierarchical linear model (HLM) analysis. Results indicated that individual level variance accounted for 84.6% of total variance and organizational level variance accounted for 15.4% of total variance in informal learning. The effect of individual level variables (task variety, task significance, workplace friendship, and learning motivation), and organizational level variables (empowerment, perception of team's support, and openness of team's communication) about informal learning were significant. Interaction effects of task variety and empowerment, task variety and perception of team's support, task significance and perception of team's support, workplace friendship and openness of team's communication, and learning motivation and perception of team's support on informal learning were found. However, there were no significant differences in nurses’ informal learning outcomes among hospitals. Detailed results and implications of these findings, limitations, and future research suggestions are discussed.
  • Neuronal filopodia borne along tips and shafts of dendrites comprise two distinct populations as evidenced by...
    Scholarship
    Creator
    Jain, Anika
    Description
    Ever since their discovery in 1880 by Ramon y Cajal, dendritic spines have evoked considerable interest in the field of cellular and molecular neuroscience. Subsequent studies into their morphogenesis, and into synaptogenesis, brought into the spotlight their putative precursors – the dendritic filopodia. This set off several lines of investigation into filopodial structure and function, notable among which is the work by Portera-Cailliau et al. who showed in 2003 that growth cone filopodia differ from shaft filopodia in terms of densities and lengths, and in their response to blocking of synaptic transmission, and of ionotropic glutamate receptors. However, they observed these differences only up to postnatal day 5. In 2010, Korobova and Svitkina reported the existence of a different actin organization in shaft filopodia at 10 days in vitro (DIV). This work fills the gap between those two studies, investigating differences between tip and shaft filopodia at 4, 7, 10 and 14 DIV, and examining structure and dynamics, as well as responses to developmental cues, specifically, Semaphorin3A (Sema3A). Using confocal microscopy to visualize filopodial membrane and actin we found that shaft filopodia are shorter than tip filopodia, and show a less dense presentation along the dendrite. We then employed the quantitative phase imaging technology of Spatial Light Interference Microscopy (SLIM) for analysis of mass change dynamics of individual filopodia. We found that tip and shaft filopodia show similar dynamics early on, but further on in development by 7 DIV shaft filopodia slow down considerably while tip filopodia continue to show fast increases and decreases in mass. Further analysis of growth rates showed that both types filopodia exhibit exponential growth during their extension, implying that the bigger the filopodium the faster it grows. Next we sought to examine the functional ramifications of these differences in tip and shaft filopodia. We investigated the differential responses of the two populations to Sema3A. We found that a 24 h exposure to Sema3A at 0-1 DIV leads to accelerated maturation of shaft filopodia as evidenced by (1) an increase in dendritic branching, (2) an acceleration of maturation into spines, and (3) into synapses. An analysis of the underlying dynamics showed that Sema3A treatment results in (1) tip filopodial movement becoming more deterministic, (2) an increase in average growth and shrinkage rates in shaft filopodia, and, (3) an increase in speed of the fastest growth and shrinkage in tip and shaft filopodia at 4 and 7 DIV. Together these findings show that Sema3A is a unique cue that acts on both tip filopodia and shaft filopodia, but with different outcomes – the former to increase dendrite lengths, and the latter to increase branching, spinogenesis and synaptogenesis. Bath application of Sema3A also elicits an axonal response, which might itself affect the cells as a whole, and could confound the filopodial read out. To avoid this, we supplemented bath application studies with investigations using microfluidic devices that enable focal, dendrite specific application of Sema3A, and, also, better replicate the in vivo layered structure of the hippocampus. Our results held true even with this sub-cellular administration of Sema3A. Taken together our findings provide further evidence for differences in the two dendritic filopodial populations – those borne on the tips, and those along the shafts, and help deconstruct the role of Sema3A in dendritic development. A greater comprehension of this diversity in the filopodial population, and its role in shaping the development of neuronal networks will not only further our understanding of the nervous system, but will also help unravel the mechanistic bases of developmental disorders and diseases.
  • Utopian connectivity to paranoid collapse: complex networks and global social ecologies in 20th-century fiction
    Scholarship
    Creator
    Ballard, Shawn C
    Description
    This project treats complex systems, specifically global social and ecological networks, as central to understanding modern explorations and experiences of utopian connectivity and stability alongside dystopian paranoia and precarity. Through an examination of the fiction of Charlotte Perkins Gilman, James Joyce, and David Mitchell, I analyze strengths and vulnerabilities of such systems. Gilman’s perfectly controlled and aggressively managed ecosystems are undercut by potentially catastrophic losses in biodiversity. Joyce’s celebratory view of networks and links across cosmic scales requires an acknowledgement and acceptance of humanity’s relative powerlessness in the face of such universal connections, which dwarf global economic and social networks. Mitchell illustrates how subtle social linkings across time and space can add up to create powerful technological, ecological, and social effects. However, the power in Mitchell’s dense global network is also its weakness; in Ghostwritten, efficiency in information transfer can be used for positive outcomes as well as to effect total apocalypse. Alongside and enmeshed with my analysis of Mitchell’s Ghostwritten, I present a comparison of manual and automatic methods I created for extracting social networks from literary texts as a first step toward developing a broadly applicable network extraction method. My proof of concept indicates that, with further iterations and refinements, it should be possible to establish a practical, reliable, and effective method for extracting and understanding social networks in novels, with the aim of using these models to understand more deeply the texts themselves and what they suggest about human experience, policy, and futurity.
  • 1-(1H-pyrrol-2-yl)-1,2-propandione is a crucial pheromone component of the rare North American cerambycid beetle...
    Scholarship
    Creator
    Diesel, Natalie Marie
    Description
    The compound 1-(1H-pyrrol-2-yl)-1,2-propanedione was recently found to be an important pheromone component of several Asian species of longhorned beetles in the subfamily Cerambycinae. Here, we report the first confirmed identification of this pyrrole as a pheromone component of a cerambycine species native to North America, the rare Dryobius sexnotatus Linsley. Headspace volatiles from males contained (R)-3-hydroxyhexan-2-one and the pyrrole (ratio 1:0.13), neither of which were detected in samples from females. A field bioassay confirmed that adults of both sexes were attracted only by the binary blend of racemic 3-ketol with the pyrrole, and not by either compound alone. Adults of another cerambycine, Xylotrechus colonus (F.), were attracted by the ketol, consistent with its being the primary component of the pheromone of this species, and attraction was not influenced by the presence of the pyrrole. This study attests to the effectiveness of pheromone-baited traps in detecting rarely encountered species of cerambycids. It also provides further evidence that the pyrrole represents another conserved pheromone motif within the Cerambycinae.
  • α7β1 integrin regulation of skeletal muscle growth in response to mechanical stimulation
    Scholarship
    Creator
    Mahmassani, Ziad S.
    Description
    The α7β1 integrin has been proposed to serve as a mechanosensor and essential regulator of myofiber remodeling given its localization at the membrane and primary role in adhering the outer extracellular matrix to the inner actin cytoskeleton. However, additional work is necessary to affirm a primary role for the α7 integrin subunit in the regulation of skeletal muscle mass. The purpose of this dissertation was to 1) use gene expression profiling to reveal potential mechanisms by which the α7BX2 integrin can promote an increase in muscle mass post- eccentric exercise, 2) determine the extent to which the α7BX2 integrin contributes to an increase in muscle mass after chronic overload, and 3) determine the extent to which α7 integrin overexpression or integrin ligand (laminin-111, LM-111) binding can improve the anabolic response to loading in aged mice. Aim 1 used microarray analysis using RNA extracted from skeletal muscle of wild type (WT) or transgenic mice (MCK:α7BX2 integrin; α7Tg), under sedentary conditions and 3 hrs after an acute bout of downhill running. The results suggest that the α7β1 integrin initiates transcription of genes that allow for protection from stress and modulation of protein synthesis, both which may contribute to positive adaptations in skeletal muscle with mechanical stimulation. In Aim 2, WT and α7Tg mice were subjected to myotenectomy (MTE) of the gastrocnemius muscles and subsequent chronic mechanical loading (CML) for 1 day (1D) or 14 days (14D). The results suggest that the α7β1 integrin augments muscle mass and adaptation, and several changes may account for this observation, including a reduction in damage and stress, yes-associated protein (YAP) content, and increased phospho- 4E-BP1 on Ser65. In Aim 3, α7Tg overexpression was not sufficient to rescue the anabolic response to chronic loading in aged mice, yet injection of LM-111 significantly restored integrin localization at the membrane and the anabolic response to a mechanical stimulus. Overall, the studies in this dissertation suggest that the α7β1 integrin is an important regulator of muscle remodeling that leads to an increase in mass in response to mechanical strain, and that manipulation of the extracellular matrix within the microenvironment may provide a novel approach towards maintenance of mechanosensing and the anabolic response across the lifespan. These observations in mice provide impetus for assessment of the relationship between extracellular matrix protein composition and subsequent α7β1 integrin-mediated remodeling within human skeletal muscle.
  • Molecular implications of prolonged DDT selection in Drosophila melanogaster
    Scholarship
    Creator
    Seong, Keon Mook
    Description
    From the advent of the use of synthetic insecticide in the first half of the twentieth century, insecticide pressure has played a critical role in the evolution of insect populations. Genome-wide monitoring for the effect of such selection has not only provided considerable insight into an understanding of these evolutionary dynamics but also as a way to elucidate changes in individual genes or gene families. Although prior comparative genetic and genomics studies have revealed a large number of individual genes and gene families that may be selectively advantageous for insects over evolutionary time scales, most studies have been limited in that the researchers did not have access to populations within a known common origin for which a given evolutionary selection pressure has been well-defined or documented. In this study, I analyzed the genomes and transcriptomes of a highly DDT-resistant (91-R) Drosophila melanogaster and its corresponding DDT-susceptible (91-C) strain in order to characterize the impact of prolonged DDT selective pressure on genetic diversity for those strains. Comparing the transcriptomic response to DDT in 91-R and 91-C, I identified a multigenic adaptive response to DDT in 91-R along with multiple roles for gene regulatory cascades around stress responses, cell survival, and neurological function. Furthermore, both the genotypic and phenotypic diversity of the phase I detoxification gene, cytochrome P450, as well as phase III detoxification gene, ABC transporter, suggest an adaptive evolutionary response to multigenerational DDT selection pressure between 91-R and 91-C. Taken together, these findings offer evidence for the impact of widespread insecticide selection pressure on genomic diversity in Drosophila evolution along with insights across the entire genome into the functional implications of such positive selection pressure.
  • Towards an agile hypervisor for software-defined networks
    Scholarship
    Creator
    Evchenko, Konstantin
    Description
    Software-Defined Networking (SDN) introduced a concept of separated control and data planes to allow programmable management of network resources. A network hypervisor is a middle layer that resides between these two planes and enables virtualization of the data plane to support efficient utilization and isolation of network resources in multi-tenant environments. Prior studies have shown the importance of hypervisors in solving a wide variety of problems in shared networking environments. In this work, we propose a design of a general-purpose, agile, and policy-aware hypervisor that can migrate virtual switches in the network. We introduce a model that formalizes the problem of virtualization and enables us to develop efficient algorithms for implementing migration. Through preliminary evaluation of our prototype we show the feasibility and low overhead of our hypervisor.
  • Establishing Procedures and Guidelines for Pedestrian Treatments at Uncontrolled Locations
    Scholarship
    Creator
    • Baireddy, Raghunandan
    • Qi, Yan
    • Fries, Ryan, N.
    • Zhou, Huaguo
    • Rab, Abdur
    Description
    Pedestrians are the most vulnerable road users. The risks to pedestrians crossing at uncontrolled locations are much higher than at signalized intersections. There has been an increasing trend in pedestrian deaths during the past decade. Specifically, pedestrian fatality as percent of total fatalities indicates an increasing trend in a ten-year period from 2005 to 2014. Several research projects funded by both federal and state transportation agencies have attempted to identify effective strategies for improving pedestrian safety within their jurisdictions. However, very little research was conducted on pedestrian safety at uncontrolled locations in Illinois. The objectives of the project were to identify the best practices of approving pedestrian crossings and pedestrian-crossing treatments at uncontrolled locations and to develop procedures and guidelines to be used by the Illinois Department of Transportation (IDOT) and local agencies. To achieve the research goal, the team conducted a comprehensive literature review of related studies and existing guidelines, a survey and interview of Illinois transportation engineers, statistical analysis of Illinois pedestrian-crash data from 2010 to 2014, and a field review of selected high-crash corridors (HCC) in Illinois. This study identified several common issues associated with the high-pedestrian-crash-prone roads, e.g., speeding, poor lighting, noncompliance with posted signage, inadequate or missing signage, or lack of conspicuity. Several geometric features were also proven to be related to pedestrian crashes; for instance, long crossing distances, insufficient sight distance, and inappropriate placement of bus stops and parking were proved to affect pedestrian safety. In addition, pedestrian-crossing treatments were classified into five categories in the study, and their effectiveness and suitable conditions were assessed and identified. Based on the research findings, a guidebook was compiled with a comprehensive discussion of strategies and treatments to enhance pedestrian safety at uncontrolled locations. The target audiences for this guidebook are transportation professionals, highway designers, traffic engineers, law enforcement officers, and safety specialists who may be involved in efforts to reduce pedestrian crashes at uncontrolled locations.
  • Sensor-based closed-loop monitoring of concrete extrusion technology for applications in large-scale construction
    Scholarship
    Creator
    Zhang, Duncan
    Description
    As 3D printing technology moves into large-scale commercial applications, ensuring consistency in products, especially when using concrete, is a significant challenge. Unlike traditional thermoplastic filaments used today, concrete possesses process parameters that can vary greatly and cause complete structural failure. Therefore a solution is to integrate real-time analysis of defects and correct them during the extrusion process. Specifically, we propose an optically precise linescan camera in two configurations as the main sources of feedback data. For testing, the sensors are directly implemented in the extrusion assembly and collect real-time data with a scale model machine. With the data gathered, we will qualify the design for the control feedback. Limits of self-adjustment, as well as the application to full-size operation, will also be reviewed.
  • Exploring image segmentation methods to segment tumors by training over a dataset marked by skilled professionals
    Scholarship
    Creator
    Somani, Varun
    Description
    This research uses chest CT scan images of lung cancer patients to examine current methods in image segmentation in the context of tumor segmentation. Potential benefits of the research include faster processing and detection time for patients as well as allowing doctors to rapidly proceed with the requisite procedures. We use both supervised and unsupervised methods to segment images. In terms of supervised methods, we use neural networks and SVMs with various “kernel tricks.” In terms of unsupervised methods, we use K-means clustering and Otsu’s method. Neural network gave the best result while other methods tended to have inferior performance. The results suggest that there is a possibility of further developing neural networks to conclusively solve the problem.
  • Microplasma jet array
    Scholarship
    Creator
    Tong, Zikang
    Description
    A microplasma jet array is a device composed of a two-dimensional array of micro-scaled gas channels that ignites flowing gas species into plasma-state jets. These devices operate at room temperature and atmospheric pressure. The potential application for these devices is bacteria and biofilm inactivation and past literature reports have demonstrated success in doing so. The device implemented in this report differentiates from previous experimentation by utilizing a physical structure with potential for plasma breakdown with ambient air as the gas feedstock. This differentiation presents an advantage because the device can use natural and abundantly available gas as its feedstock. However, further testing must be performed to fully conclude this capability.
  • Page migration and placement in hybrid memory systems using machine learning algorithms
    Scholarship
    Creator
    Vemulapati, Vibhakar
    Description
    As we reach the end of DRAM technology scaling, the prevalence of new memory technology in computers is inevitable. Phase-change memory (PCM) is an emerging non-volatile memory technology which can be denser than existing DRAM cells, but is slower. A possible solution is a hybrid PCM/DRAM memory system where we have a large capacity PCM and a DRAM used as a buffer between the processor and PCM. We will investigate various page migration algorithms on the hybrid system to maximize utilization of faster DRAM to mitigate the performance slowdown associated with using PCM as main memory. We primarily investigate the effects of speculative pre-fetching of pages in memory from PCM to DRAM using machine learning algorithms. The page rank program that we tested had irregular memory access patterns that made it difficult to predict the pages that had to be pre-fetched, causing performance slowdown when compared to running the program without modification. The overhead of predicting the prefetch page far outweighed the performance increase achieved.
  • Methods of onset detection for the bowed violin and why they failed
    Scholarship
    Creator
    Walder, Samuel
    Description
    An onset in musical signals is the time at which a note begins. Onset detection is important in computer analyses of musical performances in order to determine tempo, rhythm, and correctness. In this research, both existing and novel methods of onset detection on a dataset of 200 violin onsets played in various styles are analyzed in this thesis. Then proposed is a method for creating more robust detection algorithms, specifically an onset detection algorithm suite that splits up the challenges of onset detection into smaller parts and solves them separately.
  • Acoustic modelling through optical modulation and post processing
    Scholarship
    Creator
    Martini, Amr
    Description
    The field of acoustic modelling is split into two major categories: simulation and sensing. Acoustic simulation works directly with physical first principles and has many important applications in mechanical systems simulations and the production of synthetic sounds. Acoustic sensing is the direct measurement of acoustical properties, and its most well-known application is audio recording. This thesis develops and compares multiple techniques to perform acoustic sensing based on optical modulation, specifically to sample the mechanical vibration of a stringed instrument. The optical signal is sampled and demodulated and then further processed digitally using methods in acoustic simulation to compensate for unwanted effects. Each technique offers its own set of challenges and drawbacks, so to overcome these challenges, a hybrid solution is proposed that could offer better performance with a slight increase in overall complexity of the system.
  • Verify CMOS inverter circuit model using thin variable technique
    Scholarship
    Creator
    Meng, Yu
    Description
    There has been progress in verification of nonlinear and hybrid systems in the recent years using algorithms that combine simulation data with model-based sensitivity analysis. These approaches only handle closed models, that is, models without inputs. The naïve introduction of models of input signals breaks these approaches, as typical inputs (fast sigmoids, discontinuous functions) for analog and mixed analog-signal circuits make the system highly sensitive and the number of needed simulations grow rapidly. In this thesis, we present a new technique for verifying nonlinear and hybrid circuit models with inputs. A key result in the thesis shows that once an input signal is fixed, the sensitivity analysis of the model can be performed much more precisely. Based on this observation, we extend a discrepancy-based verification algorithm and apply it to a suite of nonlinear and hybrid models of CMOS digital circuits under different input signals. The models are low-dimensional but involve highly nonlinear ODEs, with nearly hundreds of logarithmic and exponential terms, and therefore, have challenged existing verification approaches and tools. Our implementation of the new algorithm is able to verify these models; some of our experiments analyze the metastability of bistable circuits, which involve very sensitive ODEs. Our results not only demonstrate the feasibility of our approach, but also provided interesting insights like the close connection between metastability recovery time and sensitivity.
  • A framework for implementing interactive algorithms on distributed systems
    Scholarship
    Creator
    Mudaliar, Vikram
    Description
    In this thesis, we build a framework for implementing iterative algorithms by abstracting the code for node communication. This thesis explains the building of said framework using a distributed algorithm and introduces the tools and methods used. First an algorithm was implemented and tested out on a testbed of 15 Raspberry pi’s. After the desired functionality was met, we proceeded with abstracting the code so that similar iterative algorithms could reuse the parts of the code that dealt with internode communication and communication link setup. This work is funded in part by the National Science Foundation.
  • A History of the Department of General Engineering 1868-1995
    Scholarship
    Creator
    • Engineering Publications Office
    • Jerry S. Dobrovolny, P.E.
    Description
    This history is in two parts. The first will cover the period from 1868 to 1945. The material is based on the "History of the College of Engineering of the University of Illinois 1868-1945" written by Ira O. Baker, CE '74 and Everett E. King. Also included are items given orally to the writer by his senior colleagues. The material covered since 1945 is based on the personal knowledge and records of the writer who holds a BS in general engineering.
  • Integral Abutment Bridges under Thermal Loading: Field Monitoring and Analysis
    Scholarship
    Creator
    • Riddle, Joseph, K.
    • An, Huayu
    • Svatora, Jeffrey, S.
    • Wright, Beth, A.
    • Fahnestock, Larry, A.
    • LaFave, James, M.
    • Jarrett, Matthew, W.
    • Brambila, Gabriela
    Description
    Integral abutment bridges (IABs) have gained popularity throughout the United States due to their low construction and maintenance costs. Previous research on IABs has been heavily focused on substructure performance, leaving a need for better understanding of IAB superstructure behavior and interdependent effects. This report presents findings of a field monitoring program for two Illinois IABs (which supplements findings from a parametric study portion of the overall project that are summarized in a previous volume). The field monitoring program included collecting data about (i) global bridge movements; (ii) pile, deck, girder, and approach-slab strains; and (iii) rotations at different abutment interfaces. Field results have been compared to finite-element models of each bridge in order to provide further insight into IAB behavior. Field monitoring results corroborated that IAB longitudinal expansion and contraction is somewhat less than theoretical free expansion and contraction, and is influenced by bridge skew as well. Significant girder stresses were observed, particularly at the girder bottom flange, which should be considered in design. Pile strain values indicate there is likely some reserve pile-deformation capacity typically available.
  • QR factorization over tunable processor grids
    Scholarship
    Creator
    Hutter, Edward
    Description
    The increasing complexity of modern computer architectures has greatly influenced algorithm design. Algorithm performance on these architectures is now determined by the movement of data. Therefore, modern algorithms should prioritize minimizing communication. In this work, we present a new parallel QR factorization algorithm solved over a tunable processor grid in a distributed memory environment. The processor grid can be tuned between one and three dimensions, resulting in tradeoffs in the asymptotic costs of synchronization, horizontal bandwidth, flop count, and memory footprint. This parallel algorithm is the first to efficiently extend the Cholesky-QR2 algorithm to matrices with an arbitrary number of rows and columns. Along its critical path of execution on P processors, our tunable algorithm improves upon the horizontal bandwidth cost of the existing Cholesky-QR2 algorithm by up to a factor of c^2 when solved over a c x d x c processor grid subject to P = c^2 d and E[1,P^1/3]. The costs attained by our algorithm are asymptotically equivalent to state-of-the-art QR factorization algorithms that have yet to be implemented. We argue that ours achieves better practicality and flexibility while still attaining minimal communication.
  • Stereo matching with temporal consistency using an upright pinhole model
    Scholarship
    Creator
    Jiang, Yibo
    Description
    Stereo vision, as a subfield of computer vision, has been researched for over 20 years. However, most research efforts have been devoted to single-frame estimation. With the rising interest in autonomous vehicles, more attention should be paid to temporal consistency within stereo matching as depth matching in this case will be used in a video context. In this thesis, temporal consistency in stereo vision will be studied in an effort to reduce time or increase accuracy by utilizing a simple upright camera model. The camera model is used for disparity prediction, which also serves as initialization for different stereo matching frameworks such as local methods and belief propagation. In particular, this thesis proposes a new algorithm based on this model and sped-up patchMatch belief propagation (SPM-BF). The results have demonstrated that the proposed method can reduce computation and convergence time.
  • Accelerating an efficient implementation of MLFMA with hererogeneous computing
    Scholarship
    Creator
    Ren, Wei
    Description
    This thesis investigates possible optimization on an efficient implementation of the multilevel fast multipole algorithm (MLFMA), which is intended for solving integral equations for large problems. Though MLFMA is not inherently parallel due to its tree-like computational structure, if carefully optimized, it is suitable for parallelization as the throughput and computation power becomes higher on current GPU accelerators. By dividing problems into hierarchical multilevel groups, the MLFMA can be distributed to supercomputers like the Blue Waters, utilizing massive computing resources and balancing the workload. For solving large problems with stability and fast convergence rate, several different iterative solvers are written using PETSc (Portable, Extensible Toolkit for Scientific Computation) math library routines in the MLFMA and compared for performance. The use of GPU accelerators has also been implemented in CUDA C++ and showed great improvement on Blue Waters.
  • Technical overview of public XSEDE authentication services
    Scholarship
    Creator
    • Basney, Jim
    • Navarro, John-Paul
    • Liming, R Lee
    Description
    This is a technical overview of the public authentication services that XSEDE offers and the specific features each offers. This document offers more detail than is provided by the standard XSEDE documentation.
  • Prostate cancer diagnosis with deep learning
    Scholarship
    Creator
    Wang, Bangqi
    Description
    Prostate cancer is one of the most common cancers and the second leading cause of death among American men. However, prostate cancer diagnosis is one of the most urgent problems confronted by scientific research. Accurate prostate cancer diagnosis needs a great degree of medical knowledge and is usually based on experience. It is hard for ordinary men to diagnose prostate cancer by themselves. This project aims to eliminate the knowledge barrier and provide a precise and effective method using deep learning. This project uses a deep learning neural network to build a binary classifier for prostate needle biopsies from patients. The project enlarges the prostate cancer needle biopsies dataset using randomly cutting, builds the deep learning network binary classifier, and generates predictions for the biopsies. The classifier will assign a benign or malignant label to every biopsy with accuracy near 100%.
  • Strippable coal reserves of Illinois. part 2,
    Scholarship
    Creator
    Smith, William H.
    Description
    Two folded maps in pocket.
  • Subsurface geology and coal resources of the Pennsylvanian system in Douglas, Coles, and Cumberland Counties, Illinois.
    Scholarship
    Creator
    Clegg, Kenneth Edward.
    Description
    Cover title.
  • Classification of the Pennsylvanian rocks of Illinois as of 1956,
    Scholarship
    Creator
    • Siever, Raymond.
    • Wanless, Harold R. (Harold Rollin), 1899-1970.
    Description
    Bibliography: p. 13-14.
  • A Noise Model for Beacons in an IoT Environment
    Scholarship
    Creator
    Chowdhary, Shreyans
    Description
    Bluetooth low energy is an upcoming wireless technology used by prominent researches to build a reliable indoor localization technology. This paper focuses the reliability of using such Bluetooth devices in retail environments. We carry out a series of experiments in an academic setting to evaluate the probability of receiving a packet and translate it into a noise model. These experiments are carried out for a range of broadcasting power and advertising intervals to build a robust noise model. Our noise model indicates that the probability of hearing a packet falls sub-linearly with distance. Furthermore, we develop a formula to determine the probability of receiving a packet as a function of distance, beacon power and beacon frequency.