University Library, University of Illinois at Urbana-Champaign

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Showing 81–120 of 2,363,893 items
  • Robust adaptive sampled-data control design for MIMO systems: Applications in cyber-physical security
    Scholarship
    Creator
    Jafarnejadsani, Hamidreza
    Description
    This dissertation extends the L1 adaptive control theory to sampled-data (SD) framework. Multi-input multi-output non-square (underactuated) systems are considered with different sampling rates for inputs and outputs. The sampled-data framework allows to address non-minimum phase systems, subject to less restrictive assumptions as compared to continuous time framework. It is shown that the closed-loop system can recover the response of a continuous-time reference system as the sampling time of the SD controller tends to zero. In this thesis, the L1 sampled data adaptive controller is integrated with the Simplex fault-tolerant architecture for resilient control of cyber-physical systems (CPSs). Detection and mitigation of zero-dynamics attacks are addressed and validated in flight tests of a quadrotor in Intelligent Robotics Laboratory of UIUC. The experiments show that the multirate L1 controller can e effectively detect stealthy zero-dynamics attacks and recover the stability of the perturbed system, where the single-rate conventional L1 adaptive controller fails. From the perspective of applications, the dissertation considers navigation and control of autonomous vehicles and proposes a two-loop framework, in which the high-level reference commands are limited by a saturation function, while the low-level controller tracks the reference by compensating for disturbances and uncertainties. A class of nested, uncertain, multi-input multi-output (MIMO) systems subject to reference command saturation, possibly with non-minimum phase zeros, is considered. Robust stability and performance of the overall closed-loop system with command saturation and multirate L1 adaptive controller are analyzed. Finally, a systematic analysis and synthesis method is proposed for the optimal design of filters in the L1 adaptive output-feedback structure, where the lowpass filter is the key to the trade-off between the performance and robustness of the closed-loop system. An optimization problem is formulated using the constraint on the input time-delay margin and a cost-function based on mixed L1/H2-norm performance measure. The optimization problem can be efficiently solved using linear/quadratic programming. We note that the framework of this dissertation and the multi-loop problem formulation of navigation and control of autonomous systems provide suitable synthesis and analysis tools for autonomous cyber-physical systems (CPSs), including self-driving cars, unmanned aerial vehicles (UAVs), and industrial/medical robots, to name just a few. The SD design facilitates the implementation of control laws on digital computers in CPSs, where the input/output signals are available at discrete time instances with different sampling rates.
  • An examination of gendered discourse in the discussion forums of online STEM courses
    Scholarship
    Creator
    Keyser, Genevieve M.
    Description
    Women are underrepresented in science, technology, engineering, and mathematics (STEM) fields, a problem that has roots in their disproportional enrollment and retention in STEM courses at the collegiate level. Increasingly, introductory courses across the STEM disciplines are offered online. In this project, I focus on one potential gatekeeper to women’s online success: discussion forums. Although many scholars agree that discussion forums are important components of online courses because of the collaboration and community they foster, there are gaps in our understanding of the mechanisms behind how discussion forums actually do that. One potential mechanism is language; studying the language of discussion forums can help us gain insight into students’ state of mind and propensity to form a community. By honing in on specific features of the discussion forums that have the potential to influence students’ interactions with one other (i.e., language), I can begin to develop concrete interventions to help students collaborate more effectively, develop community, and ultimately succeed in the course. The first study of this dissertation describes the state of gendered language use in two online STEM courses. The second paper explores how that language interacts with one way of structuring a discussion forum to predict students’ final grades. That structure consisted of giving students the option to post a solution to a homework problem, ask a question, or answer someone’s question. The results reveal that women and men did not differ in their language use along traditionally gendered lines, which is very promising for women in online courses; this means that it is possible that they can feel more comfortable because the language they use does not overtly mark them as a female, and therefore may subvert the typical result of the negative outcomes associated with that marker. Additionally, although not confined to one’s gender, elements of gendered discourse permeated the discussion forums. Gendered language was uniquely used among posting types and also was relevant to students’ final grades. Being a male, posting solutions, answering others’ questions, having larger word counts, as well as using more numbers and analytic language were all related to earning higher final grades.
  • Open mic? Gender and the meritocratic myth of authenticity in the cultural production of stand-up comedy
    Scholarship
    Creator
    Brown, Stephanie
    Description
    This dissertation demonstrates the ways in which gender plays a role in the validating of authenticity and merit in the cultural and industrial spaces of stand-up comedy. Merit and authenticity are arbitrary signifiers invoked by comics, fans, critics, and industry gatekeepers to protect the privilege of straight, white men who continue to dominate the field. I argue that the ideology of comedic authenticity is a means through which to police the boundaries of stand-up comedy while masking its underlying sexism, racism, and homophobia. More specifically, I argue that women, operationalized here as an industrial identity category, are constructed as comedy outsiders who must continually prove their worth through a shifting and slippery set of aesthetic and cultural norms and conditions. Further I explore the emotional and material labor women must perform to achieve success within the field, both on the local level and the industrial level. I draw attention to gatekeeping in stand-up comedy by theorizing it not as a type of rhetoric or artistic form, but as an industry with a particular culture. To this end, I connect three case-studies that highlight gendered gatekeeping in stand-up comedy: 1) A televised debate between writer Lindy West and comic Jim Norton about rape jokes and the subsequent violent backlash West dealt with on social media; 2) Reviews by television critics of female-led comedies that reinforce masculine standards of quality comedy; and 3) Interviews with women in Chicago and Champaign-Urbana’s comedy scenes that explore how they adapt to fit into masculine, and oftentimes unwelcoming, spaces or how they create their own spaces, classes, festivals, and shows. Through these case-studies, I argue that the study of women in comedy must move beyond attempts to fit women into already existing paradigms and instead use such scholarship to question common sense assumptions about humor and comedy.
  • Cumulative yearly CO2 emission by country
    Scholarship
    Creator
    Balaji, Divya
    Description
    NOTE: This is a Tableau visualization. The purpose of this visualization is to depict the cumulative growth in carbon dioxide emission levels over a 265-year period. Carbon dioxide is essential for life as it both absorbs and emits thermal radiation, which is integral to sustaining a habitable temperature for the planet. Since the Industrial Revolution, however, consumption of fossil fuels has increased at an alarming rate, disrupting the global carbon cycle and leading to a warming effect on the planet. There are numerous implications for global warming including extreme weather patterns, altered crop growth and disrupted sea levels. This entry provides a historical to present day perspective on how CO2 emissions have evolved to meet the demands of the growing population, and furthermore, how these emissions are distributed within the top ten biggest producers in the world. This diagram depicts the key drivers of carbon dioxide emission and holds the key to understanding possible avenues of mitigation of climate change. Sources: World Bank EDGAR - Emissions Database for Global Atmospheric Research
  • INHS Reports, March 1989
    Scholarship
    Creator
    Illinois Natural History Survey
    Description
    Stephen A. Forbes Biological Station
  • Hamilton-Jacobi-Bellman equation for stochastic optimal control: Applications to spacecraft attitude control
    Scholarship
    Creator
    Golpashin, Alen Envieh
    Description
    This study aims to address the problem of attitude control of spacecraft in presence of thrust uncertainty, which leads to stochastic accelerations. Spacecraft equipped with electric propulsion and other low thrust mechanisms, often experience random fluctuations in thrust. These stochastic processes arise from sources such as uncertain power supply output, varying propellant flow rate, faulty thrusters, etc. Mission requirements and mass/fuel limitations demand an optimal and proactive method of control to mitigate the thrust uncertainty and parasitic torque. Stabilizing stochastic optimal control of the satellite attitude dynamics is derived through formulation of the Hamilton-Jacobi-Bellman equation associated with a stochastic differential equation. The solution to the Hamilton-Jacobi-Bellman partial differential equation is approximated through the method of Al’brekht [1]. Extension of Albrekht method for a stochastic system was first presented in [2]; detailed derivations of linear and nonlinear stochastic control laws along with their analytical and numerical analyses are presented in this thesis. A planning method is then discussed to lower the error due to local nature of the control.
  • Global heat balance without and with solar radiation management
    Scholarship
    Creator
    Ding, Chenghao
    Description
    A linearized global heat balance model which is driven by five classes of influence on long wavelength radiation and four classes of influence on short wavelength radiation is calibrated against historical estimates of global average temperature. Additional influences are variability of solar irradiance and the initial global average temperature at the end of pre-industrial period. Industrial activities perturbs the concentration of CO2, CH4, N2O, tropospheric ozone, other greenhouse gases, and contrails in the atmosphere. Also, anthropogenic influences on short wavelength radiation including effects of land use changes on albedo, anthropogenic tropospheric aerosols and stratospheric ozone and black carbon on snow, effects of volcanoes, and variable solar irradiance are considered. The "climate sensitivity" of global average temperature response to these influences accounts for the "ice albedo" effect of global average temperature changes on absorption of short wavelength radiation and the influence of temperature changes on atmospheric water. Using the data-calibrated model, global average temperature is extrapolated to the year 2220.
  • AI concept map
    Scholarship
    Creator
    Rastovac, Matthew
    Description
    NOTE: This is an interactive visualization. Beginners to the machine learning space are often surprised at the amount of terms present in the space. It’s often very difficult to make sense of where these terms originate from, which subfield of ML they belong to, or how they relate. The goal of the AI Concept Map is to demystify these relationships by displaying a concept map of the most common machine learning fields, concepts, models, and algorithms, and how they relate to each other. Understanding where each piece fits helps to understand the whole field and make it seem less daunting.
  • Waste Reduction Policy Resources for Municipal and County Governments
    Scholarship
    Creator
    Barnes, Laura L.
    Description
    This bibliography resulted from an information request to identify resources that state and county governments can use when developing waste reduction policies. It serves as a starting point for communities looking to do similar projects.
  • INHS Reports, October 1989
    Scholarship
    Creator
    Illinois Natural History Survey
    Description
    World Bibliography of Soybean Etymology | The Illinois River: A Lesson to be Learned | Winter Refuges--The Key to Survival of Farmland Deer
  • INHS Reports, February 1990
    Scholarship
    Creator
    Illinois Natural History Survey
    Description
    Potato Leafhopper Control | Computer Software for Analyzing Evolutionary Relationships | Forest Resources of Illinois
  • 2015-2016 Illinois Hunter Harvest Report
    Scholarship
    Creator
    • Williams, Brent D.
    • Miller, Craig A.
    • Schweizer, Laura A.
    • Campbell, Linda K.
    • Conat, Ryan J.
  • The Architecture of Schools of Architecture
    Scholarship
    Creator
    • Anthony, Kathryn H.
    • Wolfgang F.E.Preiser
    • Nasar, Jack L
  • Illini Go
    Scholarship
    Creator
    • Pan, Yiting
    • George, Daniel
    • Franco, Sandra, M
    • Singh, Ravijot
    Description
    Illini Go is a mobile based virtual tour guide designed for students to explore and contribute to our university’s 150 years of myths, legends, and historical facts.
  • The geography of the European potash industry
    Scholarship
    Creator
    Mohme, Fred Stephen
    Description
    Thesis (M.A.)--University of Illinois at Urbana-Champaign, 1927.
  • Oil fields of South America, excluding Venezuela: A geographic analysis
    Scholarship
    Creator
    Clutter, Lester Woodrow
    Description
    Thesis (M.S.)--University of Illinois at Urbana-Champaign, 1951.
  • Sand and gravel resources of Peoria County
    Scholarship
    Creator
    • Hunter, Ralph E.
    • Anderson, Richard C.
  • Diet Development and Evaluation for Selected Coolwater Fishes: Final Report, F-111-R
    Scholarship
    Creator
    • Hooe, Michael L.
    • Wahl, David H.
    • Brecka, Brain J.
  • The geographic significance of the freight rate structure of Illinois
    Scholarship
    Creator
    Alexander, John Wesley
    Description
    Thesis (M.A.)--University of Illinois at Urbana-Champaign, 1941.
  • The sweet corn industry of Iroquois and Vermilion Counties
    Scholarship
    Creator
    Witzig, Frederick Theodore
    Description
    Thesis (M.S.)--University of Illinois at Urbana-Champaign, 1951.
  • Weekly Planning Guide
    Scholarship
    Creator
    Conlon, Mallory
    Description
    This planning guide is designed to help you thoughtfully approach the weekly planning of your online course. Much of this information will be shared with your students, so be sure to fill out this planning guide with your students in mind.
  • Moslem geographers 800-1300 A.D.
    Scholarship
    Creator
    Nejim, Hassan Taha
    Description
    Thesis (M.A.)--University of Illinois at Urbana-Champaign, 1952.
  • Food for Thought: Lunch Programs in the Public Library
    Scholarship
    Creator
    Lapp, Anna
    Description
    The author proposes another way that public libraries can foster student learning by providing lunch programs. The poster outlines a variety of previous studies into the subject spurred by the United States Department of Agriculture's Summer Food Service Program.
  • Statistics of One-Dimensional Cluster Motion
    Scholarship
    Creator
    • Ehrlich, Gert
    • Reed, David A.
    • Wrigley, John D.
    Description
    Coordinated Science Laboratory was formerly known as Control Systems Laboratory
  • Experimental Study of a Dielectric Antenna at the Frequency Range of 76-80 GHz
    Scholarship
    Creator
    • Chang, A.
    • Mittra, R.
    Description
    Coordinated Science Laboratory was formerly known as Control Systems Laboratory
  • Thermodynamics of Surface Clusters - Direct Observation of Re2 on W(211)
    Scholarship
    Creator
    • Ehrlich. Gert
    • Wrigley, John D.
    • Stolt, Kaj
    Description
    Coordinated Science Laboratory was formerly known as Control Systems Laboratory
  • Levels of Representation of Programs and the Architecture of Universal Host Machines
    Scholarship
    Creator
    Rau, B. Ramakrishna
    Description
    Coordinated Science Laboratory was formerly known as Control Systems Laboratory
  • Nonlinear Solutions of the Wigley Hull
    Scholarship
    Creator
    • Reyes, R.R.
    • Yen, S.M.
    Description
    Coordinated Science Laboratory was formerly known as Control Systems Laboratory
  • Artificial Intelligence and Human Error Prevention: A Computer Aided Decision Making Approach: Technical Report #2:...
    Scholarship
    Creator
    Ross, Charles B.
    Description
    Coordinated Science Laboratory was formerly known as Control Systems Laboratory
  • The Rate-Distortion Function on Classes of Sources Determined by Spectral Capacities
    Scholarship
    Creator
    Poor, H. Vincent
    Description
    Coordinated Science Laboratory was formerly known as Control Systems Laboratory
  • Steps into Computational Geometry: Notebook II
    Scholarship
    Creator
    Preparata, F.P.
    Description
    Coordinated Science Laboratory was formerly known as Control Systems Laboratory
  • Singular Perturbations and Time Scales in Modeling and Control of Dynamic Systems
    Scholarship
    Creator
    Kokotovic, Petar V.
    Description
    Coordinated Science Laboratory was formerly known as Control Systems Laboratory
  • Artificial Intelligence and Human Error Prevention: A Computer Aided Decision Making Approach: Final Report
    Scholarship
    Creator
    Chien, R.T.
    Description
    Coordinated Science Laboratory was formerly known as Control Systems Laboratory
  • Preliminary Report: A Simple Optical Technique for Filtering and Displaying Radar Data
    Scholarship
    Creator
    Miller, E.E.
    Description
    Control Systems Laboratory changed its name to Coordinated Science Laboratory
  • Rapid Scan Versus Coherent Doppler Radar for A.S.W.
    Scholarship
    Creator
    • Sherwin, C.W.
    • Ruina, J.P.
    Description
    Control Systems Laboratory changed its name to Coordinated Science Laboratory
  • Evaluation of the Icon I (JNS) Control Program
    Scholarship
    Creator
    Murray, Albert E.
    Description
    Control Systems Laboratory changed its name to Coordinated Science Laboratory
  • Censoring with a Video Mapper
    Scholarship
    Creator
    Murray, Albert E.
    Description
    Control Systems Laboratory changed its name to Coordinated Science Laboratory
  • DEPEND: A Simulation-Based Environment for System Level Dependability Analysis
    Scholarship
    Creator
    • Iyer, Ravishankar K.
    • Goswami, Kumar K.
    Description
    Coordinated Science Laboratory was formerly known as Control Systems Laboratory
  • A Minimum Area VLSI Architecture for O(logn) Time Sorting
    Scholarship
    Creator
    • Bilardi, G.
    • Preparata, F.P.
    Description
    Coordinated Science Laboratory was formerly known as Control Systems Laboratory