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Title: NON-ORTHOGONAL MULTIPLE ACCESS SYSTEM BASED ON COMBINATORIAL DESIGN
Creator: Wu, Yuteng Wu
Date: 2018, 2018-05
Description: In this thesis, a new class of multiuser Non-Orthogonal Multiple Access (NOMA) is studied. Overall, the main contributions are listed as...
Show moreIn this thesis, a new class of multiuser Non-Orthogonal Multiple Access (NOMA) is studied. Overall, the main contributions are listed as follows: Firstly, we study a new class of the space-time code (STC) based on a circulant matrix. A diagonal transmission matrix is adopted by utilizing the singular value decomposition (SVD) on the circulant matrix. After that, we present a Multiuser Multidimensional STC. This code expand the previous diagonal transmission matrix to multiple dimensions. Hence it produces a diversity due to the linear combination of all input elements. Two modified constellations are presented aiming at reducing the constellation expansion and the implementation burden. Secondly, a brief survey on state-of-the-art NOMA systems is provided, where their performance in terms of bit error rate (BER), overload capability and spectrum efficiency are compared. Thirdly, we study a NOMA system systematically. Firstly, an uplink NOMA system based on the Steiner Triple System (STS) is presented. A multiuser detection algorithm by using a reduced size vector correlator which will decrease the receiver complexity with an acceptable performance is proposed. Performance-oriented algorithm and overload-oriented algorithm aiming at handling different channel scenarios are studied. After that, we present a novel constellation forming methodology of downlink NOMA system aiming at solving the surjective-only mapping problem in NOMA systems. Compared with other methods by using constellation shaping, phase shifting and power scaling [1-4], our paradigm is capable of providing a new way to solve the surjective-only mapping with low design complexity. As far as we know, this method has not been used before. Finally, the impact of channel estimation error for NOMA system is simulated. The idea behind channel estimation is transmitting the pilot sequence and estimating the channel coefficient based on the received pilot sequence. As a future work, we will work on ARQ, cryptography and optimal designs.
Ph.D. in Electrical Engineering, May 2018
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Title: Workplace Incivility and Work- and Health-Related Outcomes: The Role of Job Embeddedness
Creator: Burke, Margaret
Date: 2024
Description: Job embeddedness has been widely studied to understand why people stay at their organization, yet recently, research has started to examine...
Show moreJob embeddedness has been widely studied to understand why people stay at their organization, yet recently, research has started to examine the so-called “dark side” of job embeddedness. Drawing from Conservation of Resource (COR) theory, this study extends research on the potential “dark side” of job embeddedness, particularly examining its relationship between workplace incivility and turnover intentions, emotional exhaustion, and physical health symptoms. Contrary to the initial hypotheses, results from the study (N = 395) indicated that on-the-job embeddedness moderated (strengthened) the positive relationship between workplace incivility and turnover intentions. As expected, on-the-job embeddedness moderated (strengthened) the positive relationship between workplace incivility and emotional exhaustion, but it did not moderate the relationship with physical health symptoms. This study contributes to the workplace mistreatment and job embeddedness literature as it explored when and how on-the-job embeddedness and its components (i.e., links, fit, sacrifice), as well as off-the-job embeddedness influence the relationships between workplace incivility and work- and health-related outcomes. The discussion explores the broader implications of on-the-job embeddedness and workplace incivility, highlighting important considerations for both researchers and practitioners in managing employee retention and well-being.
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Title: Team Game-Based Assessment: Validation of a Digital Escape Room for Measuring Team Processes
Creator: Garcia Marquez, Cintya Caribay
Date: 2024
Description: Game-based assessments (GBAs) use games to evaluate knowledge, skills, abilities, and other characteristics (KSAOs). While research on their...
Show moreGame-based assessments (GBAs) use games to evaluate knowledge, skills, abilities, and other characteristics (KSAOs). While research on their effectiveness is growing, little is known about how well game data can measure team-based constructs. This research is the first to systematically evaluate the validity of a team game-based assessment (TGBA) using a commercially available digital escape room. Guided by the Evidence-Centered Design (ECD) framework, relevant game metrics were identified, mapped to theoretical constructs of team processes, and tested against survey-based measures. Two studies were conducted to evaluate content, construct, and criterion validity. Study 1 used a Q-sort with expert judgments to establish content validity, confirming alignment between in-game behaviors and theoretical dimensions of team process such as transition, action and interpersonal team processes. Study 2 analyzed archival data from 26 teams' game logs, providing partial support for construct validity through significant correlations between game-based and survey-based measures of action and interpersonal team processes. Although the predictive power for team performance and team member satisfaction was limited, likely due to sample size, game design, and contextual factors, the results suggest that reverse-engineering existing games offers a feasible and cost-effective alternative to the time-consuming process of developing new games for assessment, particularly for low-risk scenarios. This research lays the foundation for future TGBA research and highlights the potential for future applications.
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Title: MINDFULNESS AS A MODERATOR OF SELF-ESTEEM, FUNCTIONAL IMPAIRMENT, AND PSYCOLOGICAL FLEXIBILITY IN AN ADULT ADHD POPULATION
Creator: Blanco, Rodney M.
Date: 2012-07-17, 2012-07
Description: Many adults diagnosed with ADHD have often learned to cope with and adapt to the primary symptoms (i.e. impulsivity, inattention) of ADHD....
Show moreMany adults diagnosed with ADHD have often learned to cope with and adapt to the primary symptoms (i.e. impulsivity, inattention) of ADHD. However, adults with ADHD often cite the secondary symptoms (i.e. decreased self-esteem) that may accompany ADHD as significantly impairing their lives. Much of the research to date on treatment of ADHD has focused on ameliorating the primary symptoms of adult ADHD and less attention has been focused on the secondary symptoms of ADHD. Incorporating a mindfulness intervention into the treatment of ADHD could have wide-ranging benefits as mindfulness is a self-regulatory practice that can improve attention (primary symptom) and emotional regulation (secondary symptom). The goal of the present study was to evaluate the relationships among mindfulness and self-esteem, psychological flexibility, and functional impairment in an adult ADHD sample of 133 adults self-identified as having a diagnosis of ADHD. They completed the following measures: demographics questionnaire, Accepting without judgment subscale of the Kentucky Inventory of Mindfulness Skills (KIMS), Rosenberg Self-Esteem Scale (RSE), Work and Social Adjustment Scale (WSAS), Acceptance and Action Questionnaire (AAQ-2), and the Wender Utah Rating Scale (WURS). Moderated regression analyses were used to predict an outcome (i.e., psychological flexibility, functional impairment, or self-esteem) from two predictors (i.e., ADHD symptom severity, accepting without judgment) and the interaction between the two predictors. It was found that participants who were more mindful had greater self-esteem and reported less functional impairment.
M.S. in Clinical Psychology, July 2012
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Title: LEADER AND FOLLOWER PROFILES ON CONFLICT MANAGEMENT STRATEGIES AND THE RELATIONSHIP WITH LEADER-MEMBER EXCHANGE
Creator: Burris, Kimberly R.
Date: 2011-03-23, 2011-05
Description: The current study examined leaders’ and subordinates’ conflict management strategies and how they relate to dyadic relationship quality. While...
Show moreThe current study examined leaders’ and subordinates’ conflict management strategies and how they relate to dyadic relationship quality. While a number of prior studies have investigated individual CMS styles and their association with outcomes of interest (including measures of relationship quality), this was the first study to measure and analyze full CMS profiles from both upward and downward perspectives. In high-quality LMX conditions, this study found a high degree of similarity between supervisors’ and subordinates’ full CMS profiles towards each other. Both supervisors and subordinates were higher on agreeable (i.e. integrating, obliging, and compromising) than disagreeable (i.e. dominating and avoiding) CMS. In low/moderate-quality LMX, supervisors and subordinates had dissimilar CMS profiles. The potential causes of differences between supervisor and subordinate CMS in low/moderate-quality LMX were explored. Contributions to the CMS research and practical implications were discussed.
M.S. in Psychology, May 2011
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Title: CONGRUENCE OF PROTEGE'S GENDER-ROLE AND MENTOR'S PERCEIVED GENDER-ROLE ON PROTEGE ENGAGEMENT AND MENTORING EFFECTIVENESS
Creator: Savage, Catherine M.
Date: 2013-04-22, 2013-05
Description: Higher education institutions, particularly those who specialize in Science, Technology, Engineering, and Mathematics (STEM), are experiencing...
Show moreHigher education institutions, particularly those who specialize in Science, Technology, Engineering, and Mathematics (STEM), are experiencing high turnover rates among their students. In work settings, mentors have been instrumental in the engagement and retention of employees. Therefore, we examined mentoring effectiveness and its utilization to help increase student retention and engagement for 118 students in a university in the Midwest. Also, we examined how perceived similarity between the protégé and mentor on surface- and deep-level characteristics (e.g., gender and gender role orienation) can influence both the perceived effectiveness of the mentoring relationship, as well as the protégé’s level of engagement. The results from this research found that surface-level variables, such as sociodemographic gender, were not related to the mentoring relationship or a student’s level of engagement. However, perceived similarity between the mentor and protégés on masculinity and femininity increased the protégés perceived effectiveness of the mentoring relationship. Further, perceived similarity and dissimilarity on protégé and mentor femininity increased levels of student engagement. Implications and avenues for future research are discussed.
M.S. in Psychology, May 2013
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Title: PROJECT SCHEDULING USING OPTIMIZED FINANCING
Creator: Alavipour, Seyyed Mohammadreza
Date: 2017, 2017-07
Description: Contractors need financing throughout a project, mainly due to retainage, which is the money that the owner withholds to make sure that the...
Show moreContractors need financing throughout a project, mainly due to retainage, which is the money that the owner withholds to make sure that the project is performed properly by the contractor. Even if an owner does not withhold retainage, financing is still necessary because the periodic payments made by the owner are usually delayed. All pertinent studies conducted so far have considered only one source of financing without any consideration of different sources and types of financing, times of cash provisions, interest rates, and repayment options. Actually, if one assumes a predetermined credit limit and one source of financing, as past researchers have done, the optimal financing cost and the schedule that satisfies all constraints may be different than when several sources of financing and undetermined credit limit are considered. The main objective of this research is to focus on the optimization of financing cost by developing a financing optimization model based on different financing alternatives. Far lower financing cost and higher profit are obtained by using the proposed model compared to all models developed in past research. The research is conducted in four stages of development. In Stage 1, a financing optimization model is developed for a schedule that uses normal (not accelerated) activities, and early activity start and finish times. This model can be used before the contract is signed to offer the lower bid or can be used after the contract is signed to obtain higher profit. In Stage 2, the time-cost tradeoff algorithm is added to the model developed in Stage 1, considering accelerated activities between the crash and normal durations. In Stage 3, the model developed in Stage 2 is augmented by considering variable activity start times. Finally, in Stage 4, the model developed in Stage 3 is further improved by expanding time-cost tradeoff to allow for time extensions beyond the contract duration. All models developed in these four stages provide not only minimum financing cost, but also the ideal work schedule that achieves minimum total cost and maximum profit. Moreover, these models provide specific timings for borrowing and repaying funds.
Ph.D. in Civil Engineering, July 2017
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Title: Optimum Design of a Solar Desalination Process (Spring 2002), IPRO 304E: Optimum_Design_of_a_Solar_Desalination_Process_IPRO304e_Spring2002_Final_Presentation
Creator: Kulka, Anna, Lagunova, Natasha, Mustain, Bill, Nilsson, Lina, Parai, Rajarshi, Patel, Ronak, Phillips, Shannon, Sawardecker, Erin, Sokhan, Iryna, Volberding, Beth, Walden, Jennifer
Date: 2002, 2002-05
Description: In addition to a process design topic which will be the focus of each of the six teams, the students joining this IPRO 304 will be responsible...
Show moreIn addition to a process design topic which will be the focus of each of the six teams, the students joining this IPRO 304 will be responsible for identifying, investigating, analyzing and addressing therange of complex issues associated with the process design topics, including: economic analysis, regulatory and other legal considerations, community and other social factors, safety/reliability/security, materials selection for piping and control systems, plant layout and other facility operations and maintenance constraints, etc.
Sponsorship: IIT Interprofessional Collaboratory
Project plan for IPRO 304 E: Optimum Design of a Solar Desalination Process for the Spring 2002 semester
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Title: MULTIUSER COMMUNICATIONS FOR NETWORK CODING AND NOMA
Creator: Attang, Edidiong
Date: 2018, 2018-05
Description: A paradigm shift from single user to multiuser communications helps improve system capacity for an increasing amount of applications. Such...
Show moreA paradigm shift from single user to multiuser communications helps improve system capacity for an increasing amount of applications. Such systems such as cellular mobile radio and wireless local area networks are prone to multi-access interference. Although decoding techniques has been developed, the performance of such multi-access systems is severely degraded by increasing the number of users. Network coding increases the performance of such multi-access systems by increasing its diversity over independent or orthogonal channels at least equal to the number of users. A more resource efficient strategy ensures that the number of independent channels are less than the number of users This design also known as Non-Orthogonal Multiple Access (NOMA) provides resource efficiency with the potential of managing interference. In this thesis, a specific class of Balanced Incomplete Block designs called Steiner designs is analyzed. For this class, the decoding techniques are enhanced by exploiting the structure of these designs. However, decoding criteria for a large number of independent users is prohibitively expensive. Therefore, we provide an optimized way to search through all possible combinations of independent user data. Our work presents decoding users both from a performance oriented and objective oriented viewpoint. Work in physical layer techniques for non-orthogonal transmission is evolving. The need for finding a structured decoding scheme for large number of designs will pave the way for high data rate transmissions. Also, physical implementation and analysis of decoding techniques for a large number of users will bridge the gap between theory and practice.
Ph.D. in Electrical Engineering, May 2018
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Title: LEADING IN UNCERTAIN TIMES: WHAT DRIVES FOLLOWERS' PERFORMANCE?
Creator: Arena, Fernando Lobo
Date: 2016, 2016-05
Description: Using a sample of 109 managers and 307 direct reports from a global financial services firm headquartered in the United States, we examined...
Show moreUsing a sample of 109 managers and 307 direct reports from a global financial services firm headquartered in the United States, we examined how trustworthiness affected the relationship between authentic leadership and performance in followers. Additionally, we examined how trustworthiness drives performance in an environment of strategic and structural uncertainty. Our findings indicate that authentic leadership drives follower performance and that this relationship may be mediated by benevolence. However, in a post hoc analysis we did show that benevolence mediated the relationship between relational transparency and performance. While not conclusive, there is also evidence to suggest that structural uncertainty moderates the relationship between benevolence and performance. In an environment of high structural uncertainty, followers that perceive their leaders as benevolent tend to outperform other followers.
Ph.D. in Psychology, May 2016
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Title: Chasing dreams or paying bills: How multiple jobs and calling influence work-life conflict
Creator: Vestuto, Grace
Date: 2024
Description: This study explores the relationship between multiple job-holding, work as a calling, and work-life conflict (WLC). The result of the...
Show moreThis study explores the relationship between multiple job-holding, work as a calling, and work-life conflict (WLC). The result of the comparison of the level of Work Life Conflict of multi-job holders who were separated into two groups by how they perceived their work (i.e., solely to generate income, n=61; or to support pursuing a calling, n=40) and single-job holders (n=177) yielded no significant difference. The results of the moderators of availability via communication technology (CT) and schedule flexibility revealed a significant interaction effect between work type and availability via CT on WLC, indicating that higher levels of availability via CT exacerbate WLC for those pursuing callings compared to those holding jobs. Additionally, work identified as a calling correlated higher on WLC levels than work identified as a job. Implications and future directions are discussed.
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Title: Descriptive Virtualized Reality Environment for Visual Guidance (Fall 2001) IPRO 305: Descriptive Virtualized Reality Environment for Visual Guidance IPRO305 Fall2001 Final Presentation
Creator: Agheda, Akta, Bhatt, Chirag, Bhatty, Moummar, Bhojawala, Safiya, Bodal, Aziz, Kim, Taewhan, Mathew, Arun, Soorma, Luqman, Ullal, Prasad
Date: 2001, 2001-12
Description: In this project, the utilization of virtualized reality environments to the guidance of blind or visually-impaired people will be explored. A...
Show moreIn this project, the utilization of virtualized reality environments to the guidance of blind or visually-impaired people will be explored. A virtualized reality environment will be constructed based on visual sensory information and described verbally to the user instead of presented to him graphically. One of two contexts will be selected: a static scenario in which the motorized sensors and the system are located in the environment; or a mobile scenario in which a wearable computing system is worn by the user. The technical side of the project requires students with programming skills capable and/or interested in: image analysis, computer graphics, artificial intelligence, and hardware interface and design. The non-technical side of the project requires students capable and/or interested in: analyzing the guidance needs of blind and visually-impaired people, analyzing and experimenting with different verbal descriptions of visual scenes, assessing the level of detail with which the user is comfortable, and experimenting with and assessing the effectiveness of different descriptive schemes. In the long term, the insight and ideas developed in this project may lead to their further development, testing and implementation in practical applications for those who are blind and visually-impaired or more generally for people to communicate and collaborate with each other more effectively in a virtual fashion.
Sponsorship: NA
Project Plan for IPRO 305: Descriptive Virtualized Reality Environment for Visual Guidance for the Fall 2001 semester
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Title: IIT's Solar Hydrogen project (Spring 2003) IPRO 301: IIT's Solar Hydrogen Project IPRO301 Spring2003 Final Presentation
Date: 2003, 2003-05
Description: Theobjectivesofthisprojectaretodesign,assemble and demonstrate a stand-alone distributed power generation system, which utilizes clean energy...
Show moreTheobjectivesofthisprojectaretodesign,assemble and demonstrate a stand-alone distributed power generation system, which utilizes clean energy to power an LED sign. The sole purpose of the sign is to promote solar energy and other clean energy technologies via daily messages to the Chicago highway commuters. Our specific project goal for this semester was to integrate the pieces we already have into a single, autonomous, off-grid power system.
Sponsorship: BP, BP Solar, IL- DCCA, Solarex, ComEd, Alcad, Proton Energy Systems
Project Plan for IPRO 301: IIT's Solar Hydrogen Project for the Spring 1002 semester
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Title: Design and Testing of a Lithium-Ion Battery for Hybrid Electric Vehicle Applications (Spring 2002) IPRO 362: Design_and_Testing_of_a_Lithium-Ion_Battery_System_for_Hybrid_Electric_Vehicle_Applications_IPRO362_Spring2002_Final_Presentations
Creator: Lateef, Abdul, Razack, Siddique Ali, Boeke, Jared, Lee, Jinwoo, Shaikh, Salim, Kaul, Kamayini, Albert, Ian
Date: 2002, 2002-05
Description: Li-ion cells have demonstrated excellent performance when operated at ambient temperature conditions. Still, the adverse effect of temperature...
Show moreLi-ion cells have demonstrated excellent performance when operated at ambient temperature conditions. Still, the adverse effect of temperature excursions on lithium-ion cell performance is evident when the cell is operated at elevated temperatures beyond 65 oC or at low temperatures below 0 oC. In all applications, e.g. for powering personal electronics or electric vehicles (EV), a number of cells are packed together in different configurations (parallel and series) to form a battery. It is important to keep the battery pack temperature within a fairly narrow temperature range for optimal battery performance. Thermal management for battery systems can be achieved using an IIT patented technology that incorporates phase change material (PCM) in the battery pack design. The PCM integrated in the cell and/or battery design will act as a heat sink for heat generated, for example during discharge of a Li-ion battery, which is a highly exothermic process. The heat stored will be evolved later when the battery temperature drops during battery charge, or under cold weather conditions. The objectives of this project is to design and test a 10 A-hr, 12 VDC lithium-ion battery module that can be used to power electric/hybrid vehicles(EV/HEV). The design and testing of the battery module will require a team of students with strong backgrounds in mechanical, chemical and electrical engineering. There will also be a need for law students to ensure proper protection of any new intellectual property generated from the project. A business student is required to conduct a market survey of these technologies, including the current market size and sales projections for the EV/HEV market.
Sponsorship: NA
Project plan for IPRO 362: Design and Testing of a Lithium-Ion Battery for Hybrid Electric Vehicle Applications for the Spring 2002 semester
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Title: Design and Testing of Lithium-Ion Battery for Electric/Hybrid Vehicle Applications (Fall 2001) IPRO 362: Design_and_Testing_of_Lithium-Ion_Battery_for_Electric%3AHybrid_Vehicle_Applications_IPRO362_Fall2001_Final_Presentation
Date: 2001, 2001-12
Description: Li-ion cells have demonstrated excellent performance when operated at ambient temperature conditions. Still, the adverse effect of temperature...
Show moreLi-ion cells have demonstrated excellent performance when operated at ambient temperature conditions. Still, the adverse effect of temperature excursions on lithium-ion cell performance is evident when the cell is operated at elevated temperatures beyond 65 oC or at low temperatures below 0 oC. In all applications, e.g. for powering personal electronics or electric vehicles (EV), a number of cells are packed together in different configurations (parallel and series) to form a battery. It is important to keep the battery pack temperature within a fairly narrow temperature range for optimal battery performance. Thermal management for battery systems can be achieved using an IIT patented technology that incorporates phase change material (PCM) in the battery pack design. The PCM integrated in the cell and/or battery design will act as a heat sink for heat generated, for example during discharge of a Li-ion battery, which is a highly exothermic process. The heat stored will be evolved later when the battery temperature drops during battery charge, or under cold weather conditions.The objectives of this project is to design and test a 10 A-hr, 12 VDC lithium-ion battery module that can be used to power electric/hybrid vehicles(EV/HEV). The design and testing of the battery module will require a team of students with strong backgrounds in mechanical, chemical and electrical engineering. There will also be a need for law students to ensure proper protection of any new intellectual property generated from the project. A business student is required to conduct a market survey of these technologies, including the current market size and sales projections for the EV/HEV market.
Sponsorship: IIT, All Cell Technologies, JBRO Batteries
Project Plan for IPRO 362: Design and Testing of Lithium-Ion Battery for Electric/Hybrid Vehicle Applications for the Fall 2001 semester
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Title: Developing a Wind Turbine System for Chicago (Spring 2002) IPRO 307: Developing_a_Wind_Turbine_System_for_Chicago_IPRO307_Spring2002_Final_Presentation
Date: 2002, 2002-05
Description: A French company has developed new technology for a wind turbine that produces significantly more energy for a given diameter. This company...
Show moreA French company has developed new technology for a wind turbine that produces significantly more energy for a given diameter. This company has agreed to donate a 12 kilowatt prototype unit for research purposes. The project will not only be directed to assessing the efficiency of the wind turbine, but also to the development of a unique stable energy source that integrates several renewable energy sources. The City of Chicago Department of Environment has agreed to partner with IIT in the development of this system. This IPRO team will be responsible for developing the research plan which will include but not be limited to: 1) identifying and assessing alternate locations for siting the wind turbine prototype, 2) developing the research protocol, 3) evaluating wind data in the Chicago area, 4) reviewing the legal aspects of the project including permitting requirements, 5) identifying potential contractors for the installation of the prototype, and 6) developing a preliminary design for the electrical generating system described above.
Sponsorship: NA
Project Plan for IPRO 307: Developing a Wind Turbine System for Chicago for the Spring 2002 semester
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Title: DATA-DRIVEN OPTIMIZATION OF NEXT GENERATION HIGH-DENSITY WIRELESS NETWORKS
Creator: Khairy, Sami
Date: 2021
Description: The Internet of Things (IoT) paradigm is poised to advance all aspects of modern society by enabling ubiquitous communications and...
Show moreThe Internet of Things (IoT) paradigm is poised to advance all aspects of modern society by enabling ubiquitous communications and computations. In the IoT era, an enormous number of devices will be connected wirelessly to the internet in order to enable advanced data-centric applications. The projected growth in the number of connected wireless devices poses new challenges to the design and optimization of future wireless networks. For a wireless network to support a massive number of devices, advanced physical layer and channel access techniques should be designed, and high-dimensional decision variables should be optimized to manage network resources. However, the increased network scale, complexity, and heterogeneity, render the network unamenable to traditional closed-form mathematical analysis and optimization, which makes future high-density wireless networks seem unmanageable. In this thesis, we study the design and data-driven optimization of future high-density wireless networks operating over the unlicensed band, including Radio Frequency (RF)-powered wireless networks, solar-powered Unmanned Aerial Vehicle (UAV)-based wireless networks, and random Non-Orthogonal Multiple Access (NOMA) wireless networks. For each networking scenario, we first analyze network dynamics and identify performance trade-offs. Next, we design adaptive network controllers in the form of high-dimensional multi-objective optimization problems which exploit the heterogeneity in users' wireless propagation channels and energy harvesting to maximize the network capacity, manage battery energy resources, and achieve good user capacity fairness. To solve the high-dimensional optimization problems and learn the optimal network control policy, we propose novel, cross-layer, scalable, model-based and model-free data-driven network optimization and resource management algorithms that integrate domain-specific analyses with advanced machine learning techniques from deep learning, reinforcement learning, and uncertainty quantification. Furthermore, convergence of the proposed algorithms to the optimal solution is theoretically analyzed using mathematical results from metric spaces, convex optimization, and game theory. Finally, extensive simulations have been conducted to demonstrate the efficacy and superiority of our network optimization and resource management techniques compared with existing methods. Our research contributions provide practical insights for the design and data-driven optimization of next generation high-density wireless networks.
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Title: TOPOLOGY OPTIMIZATION OF SYNCHRONOUS ELECTRIC MACHINES
Creator: Guo, Feng
Date: 2021
Description: Topology optimization of electric machine is attractive because of the increased design degree of freedom compared to conventional electric...
Show moreTopology optimization of electric machine is attractive because of the increased design degree of freedom compared to conventional electric machine design techniques. Also, a topology optimization approach does not necessarily require the use of a geometric template where dimensions are controlled by parameters. In this dissertation, a density-based magneto-structural topology optimization approach for the design of synchronous reluctance machine (SynRel), interior permanent magnet synchronous machine (IPMSM), and wound field synchronous machine (WFSM) rotors is developed. Depending on the electric machine type, the optimization problems are divided into single material and multi-material topology optimizations. A mass thresholding function is introduced to overcome the intermediate density issue which is caused by combining the magnetic and structural topology optimization problems. SynRel and IPMSM optimization examples are presented in the single material topology optimization section. For the multi-material topology optimization, in order to properly define the boundary conditions between multiple materials, a virtual region calculation approach is proposed. In the WFSM topology optimization, the copper field winding is represented by a virtual region. The contact and frictionless boundary conditions between the copper field winding and the electrical steel is defined and the centripetal load of the copper winding are equivalently calculated and applied on the elements on the electrical steel next to the boundary between the copper field winding and the steel of the WFSM pole tip. In additional to the total free-form magneto-structural topology optimization, a density-based combined dimensional and topology optimization is developed for the design of IPMSM and WFSM rotors. Both the dimensional and topological control variables are integrated to simplify the optimization problem. For IPMSM rotor design, the permanent magnet (PM) block shape is preferred to be retained where dimensional optimization could be used. The proposed dimensional topology optimization approach can fit in this design situation, where the PM is designed using dimensional control variables where the rest of the design domain is optimized using topology optimization. To allow the block or rectangular magnet to move and change size, the surrounding design domain mesh must deform or distort. The Laplace's smoothing mesh deformation technique is used in this approach and helper lines are connected to allow greater mesh deformation range and to avoid over mesh distortion. In addition to IPMSMs, a WFSM example is presented optimizing the winding region using dimensional optimization and the rotor core using topology optimization. An alternative combined dimensional and topology optimization approach has also been developed primarily for the design of the IPMSM rotors. In this approach, the mesh deformation is not required but there is no explicit geometric boundary between the rectangular permanent magnet and the surrounding electrical steel and air. In this approach, the PM density is expressed as a Heaviside rectangular function of dimensional variables. The function is projected onto the rotor mesh. Modified material penalizations are used. Topology optimization then controls the deposition of electrical steel and air. Three different IPMSM examples are presented with different dimensional control variables, including the PM position, size and angle.
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Title: DATA-DRIVEN FIRST-PRINCIPLES STUDY OF ORDERING PHENOMENA IN COMPLEX ALLOYS
Creator: Kim, George
Date: 2021
Description: Determining the chemical (dis)ordering behavior in materials such as high entropy alloys (HEAs), and ternary Laves phases is fundamental to...
Show moreDetermining the chemical (dis)ordering behavior in materials such as high entropy alloys (HEAs), and ternary Laves phases is fundamental to developing structure-property relations that can be used as guiding principles for alloy design. A common obstacle in materials engineering is that an improvement of a material property comes at the expense of some other desirable properties. For example, trade-offs may be made between strength and ductility, or strength and density, etc. The large compositional and configuration space of possible HEAs, and Laves phases contain potential candidate materials with a balance of optimized properties and tunable structural and functional properties. However, fully exploring the large compositional and configurational space with experimental or even high-throughput Density Functional Theory (DFT) approaches is infeasible, and as of yet, predictive rules for phase stability and chemical (dis)order in HEAs, and Laves phases are still open questions.In this thesis, a HEA with chemical disorder, Al0.3CoCrFeNi, was studied using complementary experimental, DFT, and ML methods. The chemical disorder within the HEA resulted in a severely distorted lattice leading to a reduction in stiffness. Temperature dependence of chemical ordering behavior is studied in NbTaTiV and NbTaTiVZr HEAs using Monte Carlo (MC) simulations, which predicts short-range ordering (SRO) as well as short-range clustering (SRC) behavior in both HEAs. The compositional dependent behavior of substitutional ordering in two ternary Laves phases is evaluated and compared using cluster expansion (CE) models and Monte Carlo (MC) simulations.
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Title: HERBS AND SPICES ON ENDOTHELIAL FUNCTION OVER 24 HOURS: A RANDOMIZED, CONTROLLED TRIAL
Creator: Thorat, Rajrajeshwari Sunil
Date: 2021
Description: Modern-day eating patterns are characterized by readily available carbohydrates and/or fats and have consistently been shown to disturb...
Show moreModern-day eating patterns are characterized by readily available carbohydrates and/or fats and have consistently been shown to disturb endothelial function. Recent investigations suggest herb and spice blends have beneficial effects in reducing inflammation and increasing endothelial function in humans. This study was designed to characterize the effect of herbs and spices on endothelial function as measured by flow-mediated dilation (FMD) over 24 h using a challenge meal paradigm. In a randomized, single-blinded, 4-arm, crossover trial, sixteen overweight/obese adults (BMI = 28.4 ± 2.5 kg/m2; age = 39 ± 15 years) consumed a high carbohydrate high-fat meal (≈ 41% Fat and ≈46% Carbohydrate of total Kcal) with or without the spices combinations, including Italian herbs (rosemary, basil, thyme, oregano, and parsley), cinnamon, and pumpkin pie spice (cinnamon, ginger, nutmeg, and allspice) on four separate days at least three days apart. Meals provided to subjects were customized according to the individual's energy needs to maintain the body weight. The meal was composed of 35% of the daily estimated energy requirement. FMD was performed at 0, 1, 2, 4, 5.5, 7, and 24h. A pressure cuff was positioned below the elbow, artery diameter was measured before the pressure is applied and then inflated to 220 mmHg systolic pressure for 5 minutes. Immediately after cuff deflation, brachial artery vessel diameter was measured to obtain peak vessel relaxation. FMD was calculated as a percentage change in artery diameter before and after the release of the pressure. Baseline (t= 0 h) %FMD change was not significantly different between the treatments (p>0.05). There was no significant increase in the %FMD after consuming the control meal at all time points (p>0.05). Consumption of meals with Italian herb mix, cinnamon, and pumpkin pie spice significantly increased %FMD at 24 h compared to the control meal (mean ± standard error at 24 h, 7.83 ±0.89%, 7.98±0.95% and 8.44±0.70% vs 6.03±0.79%, respectively, p˂0.05). Furthermore, % FMD was significantly increased at t= 24h in Italian herb mix and cinnamon compared to their respective baselines 5.68 ± 0.37% to 7.83 ± 0.89% (p=0.01) and 6.43 ± 0.89% to 7.89 ± 0.95% (p=0.03), respectively. The results of this research indicate that spices may be beneficial for improving endothelial function after 24 h consumption, suggesting bioactivity of herbs and spices on endothelial function will be related to their time course of bioavailability of bioactive components. This was the first study that assessed the effect of herbs and spices over 24 hours using FMD. Understanding the mechanism of how these herbs and spices improve endothelial function will be the subject of future research.
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