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Title: Large-Signal Transient Stability and Control of Inverter-Based Resources
Creator: Wang, Duo
Date: 2024
Description: Renewable generation, including solar photovoltaic (PV) systems, type 3 and 4 wind turbine generation systems (WTG), battery energy storage...
Show moreRenewable generation, including solar photovoltaic (PV) systems, type 3 and 4 wind turbine generation systems (WTG), battery energy storage systems (BESS), as well as high voltage direct current (HVDC) and flexible alternating current (FACT) transmission system devices with increasing penetration level are being connected to the bulk power systems (BPS) via power electronic (PE) converters as the interface, referred to as the inverter-based resources (IBRs) on the transmission and sub-transmission levels or distributed energy resources (DERs) located on the distribution level. The IBR is almost entirely defined by the control algorithms and found to be more prone to experiencing large disturbances due to the lack of the conventional synchronous machine (SM) intrinsic synchronous characteristics and mechanical inertia, as well as being in smaller capacity sizes. Thus, these reasons motivate this dissertation to study the large-signal transient stability and control of IBRs for reliable grid integration and rapid grid transformation. For large-signal stability analysis methods, Lyapunov-based methods are the fundamental theory used to characterize the stability issues with analytical solutions, although other non-Lyapunov methods could also be very helpful. A main difficulty hindering the widespread adoption of the Lyapunov stability analysis method is the difficulty of finding the proper Lyapunov function candidate for a higher dimensional nonlinear system. The Port-Hamiltonian (PH) nonlinear control theory is explored in this dissertation as a promising theoretical framework solution addressing this challenging issue. A PH-based tracking and robust control method is proposed to facilitate the practical application of the PH framework in IBR controls. In addition, considering the typical grid-forming (GFM) IBR control with a first-order low pass filter (LPF) block is usually involved with control saturation function for protection purposes under abnormal operating conditions with anti-windup issue in practical implementation, a PH-based bounded LPF (PH-BLPF) control is proposed to incorporate this in the large-signal PH interconnection modeling framework while preserving the robust tracking Lyapunov stability with improved transient dynamic performance and stability margin.Moreover, specific real-world transient synchronization stability issues, such as the grid voltage large fault disturbance case, are studied. In addition, to meet the recent emerging IBR grid code requirements, such as the current magnitude limitation, grid support function, and fault recovery capability of GFM-VSCs, a virtual impedance-based current-limiting GFM control with enhanced transient stability and grid support is proposed.
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Title: Two Essays on Mergers and Acquisitions
Creator: Xu, Yang
Date: 2024
Description: This dissertation is composed of two self-contained chapters that both relate to mergers and acquisitions (M&A). In the first essay, we...
Show moreThis dissertation is composed of two self-contained chapters that both relate to mergers and acquisitions (M&A). In the first essay, we examine the Delaware (DE) reincorporation effect on firms’ post-IPO behaviors on mergers and acquisitions. We find that firms’ DE reincorporation decisions enhance the likelihood of engaging in M&A as targets. However, as a tradeoff, DE reincorporated firms get lower takeover valuations compared to stay-at-home-state firms, and the acquisition of reincorporated firms is less likely to be successful. Our second essay aims to explore the role of the options market in price discovery for M&A. We find that the predictive power of the changes in implied volatility of the target firm stock for the takeover outcome is statistically and economically significant. The risk arbitrage portfolios incorporating filters derived from the options on stocks of the target firms generate annualized risk-adjusted abnormal returns between 2.6% and 5%, depending on the portfolio weighting method, the threshold of filters for the implied volatility change, and the asset pricing models applied for abnormal returns. The results are robust to different empirical setups and are not explained by traditional factors.
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Title: Heterogeneous Workloads Study towards Large-scale Interconnect Network Simulation
Creator: Wang, Xin
Date: 2023
Description: High-bandwidth, low-latency interconnect networks play a key role in the design of modern high- performance computing (HPC) systems. The ever...
Show moreHigh-bandwidth, low-latency interconnect networks play a key role in the design of modern high- performance computing (HPC) systems. The ever-increasing need for higher bandwidth and higher message rate has driven the design of low-diameter interconnect topologies like variants of dragonfly. As these hierarchical networks become increasingly dominant, interference caused by resource sharing can lead to significant network congestion and performance variability. Meanwhile, with the rapid growth of the machine learning applications, the workloads of future HPC systems are anticipated to be a mix of scientific simulation, big data analytics, and machine learning applications. However, little work has been conducted to understand performance implications of co-running heterogeneous workloads on large-scale dragonfly systems. There is a greater need to study how different interconnect technologies affect workload performance, and how conventional scientific applications interact with emerging big data applications at the underlying interconnect level. In this work, we firstly present a comparative analysis exploring the communication interference for traditional HPC applications by analyzing the trade-off between localizing communication and balancing network traffic. We conduct trace-based simulations for applications with different communication patterns, using multiple job placement policies and routing mechanisms. Then we develop a scalable workload manager that provides an automatic framework to facilitate hybrid workload simulation. We investigate various hybrid workloads and navigate various application-system configurations for a deeper understanding of performance implications of a diverse mix of workloads on current and future supercomputers. Finally, we propose a scalable framework, Union+, that enables simulation of communication and I/O simultaneously. By combining different levels of abstraction, Union+ is able to efficiently co-model the communication and I/O traffic on HPC systems that equipped with flash-based storage. We conduct experiments with different system configurations, showing how Union+ can help system designers to assess the usefulness of future technologies in next-generation HPC machines.
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Title: Empowering Visually Impaired Individuals With Holistic Assistance Using Real-Time Spatial Awareness System
Creator: Yu, Xinrui
Date: 2024
Description: The integration of artificial intelligence (AI) into daily life opens unprecedented avenues for enhancing the experiences of visually impaired...
Show moreThe integration of artificial intelligence (AI) into daily life opens unprecedented avenues for enhancing the experiences of visually impaired individuals, offering them greater autonomy and quality of life. This thesis introduces a Visually Impaired Spatial Awareness (VISA) system designed to assist visually impaired individuals holistically through a structured approach. At the foundational level, the VISA system incorporates several key technologies to interpret the surroundings and assist in basic navigation tasks. It utilizes Augmented Reality (AR) markers to facilitate recognition of places and aid in navigation, employs neural network models for advanced object detection and tracking, and leverages depth information for accurate object localization. Progressing to the intermediate level, the VISA system integrates the data obtained from object detection and depth sensing to assist in more complex navigational tasks such as obstacle avoidance and pathfinding toward a desired destination. At the advanced level, the VISA system synthesizes the capabilities developed at the foundational and intermediate levels to enhance the spatial awareness of visually impaired users, allowing them to undertake complex tasks, such as navigating complex environments and locating specific items. The VISA system also emphasizes efficient human-machine interaction, incorporating text-to-speech and speech-to-text technologies to facilitate natural and intuitive communication between the user and the system. The VISA system's performance was evaluated in different environments simulating real-world scenarios. The experimental results show that the user can interact with our system intuitively with minimal effort, and affirm that the VISA system can effectively assist the visually impaired user in locating and reaching for objects, navigating indoors, identifying merchandise, and recognizing both handwritten and printed texts.
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Title: Grace Gospel Mission, Chicago, Illinois, ca. 1945
Creator: Illinois Institute of Technology
Date: 1943-1948
Description: Photograph of the front of Grace Gospel Mission, 3138(?) South State Street. This storefront church was demolished ca. 1950. Date of...
Show morePhotograph of the front of Grace Gospel Mission, 3138(?) South State Street. This storefront church was demolished ca. 1950. Date of photograph is unknown. Date range listed is approximate.
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Collection: Office of Communications and Marketing photographs, 1905-1999

Title: Grand View Blvd...Los Angeles Jan 91
Creator: Gordon, Robert Philip
Date: 1991-01
Description: Watercolor painting of the intersection of an unknown street with Grand View Boulevard in Los Angeles, California.
Collection: Robert Philip Gordon papers, 1963-2010

Title: New Object
Creator: Zhang, He

Title: Ink and Pastel Drawing, undated
Creator: Henry, Mary Dill, 1913-2009
Description: Untitled ink and pastel drawing by Mary Henry of a hand, possibly her own. Drawing is undated.
Collection: Mary Dill Henry Papers, 1913-2021

Title: Gospel Mission Baptist Church, Chicago, Illinois, ca. 1945
Creator: Illinois Institute of Technology
Date: 1943-1948
Description: Photograph of the front of the Gospel Mission Baptist Church. Date of photograph is unknown. Date range listed is approximate.
Collection: Office of Communications and Marketing photographs, 1905-1999

Title: Design on a Hill
Creator: Henry, Mary Dill, 1913-2009, Ziegler, William
Description: Photograph of Design on a Hill (1940), a stone lithograph by Mary Dill Henry, completed as a part of her studies with Ray Bertrand....
Show morePhotograph of Design on a Hill (1940), a stone lithograph by Mary Dill Henry, completed as a part of her studies with Ray Bertrand. Handwritten inscription on verso: "Lithograph #2, 1940 Federal Art Project, litho pencil on stone. Ray Bertrand, San Francisco Art Project, was my teacher." Typewritten inscription on verso: "Mary Henry: Design on a Hill, 1940. Stone lithograph, 12" x 16". Courtesy of the artist, Freeland, WA. Photo: Wm. Ziegler." Photograph by William Ziegler. Date of photograph unknown.
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Collection: Mary Dill Henry Papers, 1913-2021

Title: Federal Arts Project mosaic, Monterey, California
Description: Photograph of a mural completed in Monterey, California as part of a the Federal Arts Project by Mary Dill, likely in the late 1930s,...
Show morePhotograph of a mural completed in Monterey, California as part of a the Federal Arts Project by Mary Dill, likely in the late 1930s, described on the inscription of a similar photograph as "Mary Dill's first mosaic for the Federal Art Project - the first governor's house in Monterey, Calif." Photographer unknown. Date of photograph unknown.
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Collection: Mary Dill Henry Papers, 1913-2021

Title: Federal Arts Project mosaic, Monterey, California
Description: Photograph of a mural completed in Monterey, California as part of a the Federal Arts Project by Mary Dill, likely in the late 1930s,...
Show morePhotograph of a mural completed in Monterey, California as part of a the Federal Arts Project by Mary Dill, likely in the late 1930s, described on the inscription of a similar photograph as "Mary Dill's first mosaic for the Federal Art Project - the first governor's house in Monterey, Calif." Photographer unknown. Date of photograph unknown.
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Collection: Mary Dill Henry Papers, 1913-2021

Title: Federal Arts Project mosaic, Monterey, California
Description: Photograph of a mural completed in Monterey, California as part of a the Federal Arts Project by Mary Dill, likely in the late 1930s,...
Show morePhotograph of a mural completed in Monterey, California as part of a the Federal Arts Project by Mary Dill, likely in the late 1930s, described on the inscription of a similar photograph as "Mary Dill's first mosaic for the Federal Art Project - the first governor's house in Monterey, Calif." Photographer unknown. Date of photograph unknown.
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Collection: Mary Dill Henry Papers, 1913-2021

Title: Federal Arts Project mosaic, Monterey, California
Description: Photograph of a mural completed in Monterey, California as part of a the Federal Arts Project by Mary Dill, likely in the late 1930s....
Show morePhotograph of a mural completed in Monterey, California as part of a the Federal Arts Project by Mary Dill, likely in the late 1930s. Inscription on verso: "Mary Dill's first mosaic for the Federal Art Project - the first governor's house in Monterey, Calif." Photographer unknown. Date of photograph unknown.
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Collection: Mary Dill Henry Papers, 1913-2021

Title: Plate 5
Creator: Henry, Mary Dill, 1913-2009
Date: 1936-1939
Description: Untitled ink drawing identified on recto as "Plate 5." Date of drawing is unknown. Date range listed is approximate.
Collection: Mary Dill Henry Papers, 1913-2021

Title: Ink Drawings, 1981
Creator: Henry, Mary Dill, 1913-2009
Date: 1981-02-17
Description: Untitled ink drawings by Mary Henry. Inscription on verso reads "8' x 6' Feb 17 81" and also contains what appear to be mathematical...
Show moreUntitled ink drawings by Mary Henry. Inscription on verso reads "8' x 6' Feb 17 81" and also contains what appear to be mathematical calculations.
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Collection: Mary Dill Henry Papers, 1913-2021

Title: LOCAL VISCOELASTIC PROPERTIES OF SOFT ANISOTROPIC FIBROUS TISSUE
Creator: Gallo, Nicolas Remy
Date: 2020
Description: The current aging population, with more than 80 million "baby boomers", will present a steep medical challenge for our society in a...
Show moreThe current aging population, with more than 80 million "baby boomers", will present a steep medical challenge for our society in a foreseeable future. Half of the adults over 85 years old are predicted to be diagnosed with Alzheimer's disease by 2050. With healthcare cost reaching over 700 billion dollars in the United States, early detection of Alzheimer's disease (AD) and other co-existing neurodegenerative diseases is crucial to improve the recovery odds in patients and to decrease individual care cost. This work seeks to tackle this problem by proposing a novel computational framework toward improving the measurement of shear visco-elastic properties of brain white matter (WM), which vary with age. These measurements practically represent the effective (average) response of many cells and are typically obtained by using rheology or elastography. Although the former is direct, the latter requires the solution of an inverse problem based on a priori mechanical tissue model. The mechanical anisotropy of WM has previously not been fully explored although many inconsistencies have been reported in brain MRE experiments. To account for these inconsistencies a transversely isotropic constitutive model for the brain WM is proposed to interpret prior experiments involving 7 young and 4 older healthy men. By employing a novel inversion scheme, we report the local variation of the effective transverse and axial shear moduli in two well aligned WM structures (corpus callosum: CC; and cortical spinal tract: CST) for both the young and old cohort of healthy subjects part of the study. This work reports statistically significant changes in local regional variation of the transverse modulus across the CC for the young cohort. In the older cohort, the trend was similar yet not statistically significant. A novel candidate biomarker, the shear anisotropy metric, defined as the ratio of the transverse and axial shear moduli, found statistically significant local regional variation across the CC but not in the CST. Healthy aging was observed to decrease both transverse and axial in both CC and CST, although the variation was significant only for the CC. Finally, in an effort to understand the cause of effective transverse mechanical properties variation in WM with aging, the connection between effective and intrinsic contribution of WM cellular constituents is established. The intrinsic mechanical contributions of axons and glial matrix are separated by fitting the estimates of the effective shear moduli to a microscopic composite fiber model of myelinated axons embedded in the glial matrix. This work provides a method to establish a baseline for healthy brain mechanical properties thus promising to increase the specificity of MRE toward early diagnosis of neurodegenerative diseases. Additional oscillating disc rheology experiments with decellularized porcine myocardium, and the fabrication of a stable heterogeneous phantom matching the mechanical, diffusional and electrical properties of the WM provide foundational knowledge for due development and validation of MRE methodologies employed in other tissues.
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Title: Students building a snowman, Illinois Institute of Technology, Chicago, Illinois, 1980s
Creator: Lightfoot, Robert M., III
Date: 1980-1989
Description: Photograph of students building a snowman on present day Siegel Field, north of S.R. Crown Hall on the Illinois Tech campus. Date of...
Show morePhotograph of students building a snowman on present day Siegel Field, north of S.R. Crown Hall on the Illinois Tech campus. Date of photograph is unknown. Date range listed is approximate.
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Collection: Office of Communications and Marketing photographs, 1905-1999

Title: Spring Thing tricycle race, Illinois Institute of Technology, Chicago, Illinois, ca. 1968-1971
Date: 1968-1971
Description: Photograph of the tricycle race during the Spring Thing. Spring Thing, sponsored by the Union Board, occurred during the fall semester,...
Show morePhotograph of the tricycle race during the Spring Thing. Spring Thing, sponsored by the Union Board, occurred during the fall semester, usually in October. The tricycle race, first held in 1968, was a highlight of the annual festivities. Photographer unknown. Date of photograph is unknown. Date range listed is approximate.
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Collection: Office of Communications and Marketing photographs, 1905-1999

Title: Women's Hall (later Lewis Hall), Illinois Institute of Technology, Chicago, Illinois, ca. 1966
Date: 1965-1966
Description: Photograph of Lewis Hall, designed by Mittelbusher & Tourtelot and constructed in 1966. The building is located at 70 East 33rd Street, and...
Show morePhotograph of Lewis Hall, designed by Mittelbusher & Tourtelot and constructed in 1966. The building is located at 70 East 33rd Street, and was known at the time of its construction as Women's Hall. Date of photograph is unknown. Date range listed is approximate. Photographer unknown.
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Collection: Office of Communications and Marketing photographs, 1905-1999

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