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Title: LATTICE DESIGN OF THE INTEGRABLE OPTICS TEST ACCELERATOR AND OPTICAL STOCHASTIC COOLING EXPERIMENT AT FERMILAB
Creator: Kafka, Gene
Date: 2015, 2015-05
Description: The Integrable Optics Test Accelerator (IOTA) storage ring at Fermilab will serve as the backbone for a broad spectrum of Advanced Accelerator...
Show moreThe Integrable Optics Test Accelerator (IOTA) storage ring at Fermilab will serve as the backbone for a broad spectrum of Advanced Accelerator R&D (AARD) experiments, and as such, must be designed with significant flexibility in mind, but without compromising cost efficiency. The nonlinear experiments at IOTA will include: achievement of a large nonlinear tune shift/spread without degradation of dynamic aperture; suppression of strong lattice resonances; study of stability of nonlinear systems to perturbations; and studies of di↵erent variants of nonlinear magnet design. The ring optics control has challenging requirements that reach or exceed the present state of the art. The development of a complete self-consistent design of the IOTA ring optics, meeting the demands of all planned AARD experiments, is presented. Of particular interest are the precise control for nonlinear integrable optics experiments and the transverse-to-longitudinal coupling and phase stability for the Optical Stochastic Cooling Experiment (OSC). Since the beam time-of-flight must be tightly controlled in the OSC section, studies of second order corrections in this section are presented.
Ph.D. in Physics, May 2015
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Title: ANALYSIS AND CONTROL OF COMPRESSION-IGNITION AND SPARK-IGNITED ENGINES OPERATING WITH DUAL-FUEL COMBUSTION STRATEGY
Creator: Kassa, Mateos
Date: 2017, 2017-07
Description: In recent years, the implementation of a dual-fuel combustion strategy has been explored as a means to improve the thermal efficiencies of...
Show moreIn recent years, the implementation of a dual-fuel combustion strategy has been explored as a means to improve the thermal efficiencies of internal combustion engines while simultaneously reducing their emissions. The dual-fuel combustion strategy was introduced in compression ignition engines to control the combustion phasing by varying the proportion of two simultaneously injected fuels, and altering the combustion timing. The dual-fuel injection strategy also allowed to extend the load limitation of advanced combustion engines, since the two injected fuel ignite in succession reducing the high peak pressures that generally act as a limiting factor. In spark-ignited (SI) engine, the implementation of a dual-fuel combustion strategy serves as an alternative approach to avoid knock (the inadvertent auto-ignition of the fuel mixture). Although conventional engines rely on delaying spark timing to avoid knocking cycles (which significantly reduces the thermal efficiency), the dual-fuel SI engine rely on the simultaneous injection of a low knock resistance and high knock resistance fuel to dynamically adjust the fuel resistance to knock as required. The dual-fuel SI engine thereby successfully suppresses knock without compromising the engine efficiency. Despite the benefits of the dual-fuel combustion strategy, several challenges arise in its implementation, especially when it is implemented along with other advanced combustion strategy leveraging variable valve timing, exhaust gas recirculation, turbocharging, and so forth. This study explores some of these challenges and addresses them from a control standpoint. Cylinder-to-cylinder variations is identified as one of the main challenges. An in-cylinder oxygen estimation strategy and modification to the conventional fueling strategy are proposed as approaches to reduce the combustion variations. In SI engines, the valve dynamics in transient operations are shown to negatively impact the dual-fuel control strategy. The effect of the valve timing on knock propensity and the resulting effect on the fueling strategy is investigated. Finally, the dual-fuel SI engine relies on measurements of the combustion intensity to adjust the fuel split between the low RON and high RON fuel. The implementation of a conventional knock control is shown to be counterintuitive for dual-fuel SI engines due to the highly reactive nature of the controller and the deterministic approach that assumes cycle-to-cycle correlation of the combustion intensity. Statistical investigation of the combustion intensity metric is conducted to identify key properties that can be leveraged for more effective control strategy.
Ph.D. in Mechanical, Material and Aerospace Engineering
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Title: VALUE OF BATTERY STORAGE SYSTEM IN THE FEREQUENCY REGULATION MARKETS OF PJM AND CAISO
Creator: Khorsand, Shervin
Date: 2017, 2017-05
Description: With an increasingly urgent need to decrease our utilization of fossil fuels, renewable power sources such as wind and solar are being...
Show moreWith an increasingly urgent need to decrease our utilization of fossil fuels, renewable power sources such as wind and solar are being incorporated in the electricity grid. However, these sources lack the conventional reliability that fossil fuels, such as natural gas, and oil have previously provided. The solution lies in energy storage, and exactly why battery storage systems are the means for renewable energy sources to become truly transformative and revolutionize the energy market. In the first part of this paper, a comprehensive summary of the different types of energy storage technologies have been provided along with their features, which make each technology suitable for different applications. Next, a detailed chapter focused on battery storage systems and their properties is provided along with the ancillary services they offer as sustenance and support sources integrated in the electric grid. These service are integral to the continuous transmission of power to consumers, and necessary for the supply to meet end-user demands. Among these service include frequency regulation as well as spinning reserve services, the latter being important under emergency condition following a power disruption. Regulation services however, are constantly required for grid stability and reliability, which is why this service was selected for further market analysis. For this market analysis, the California Independent Systems Operator (CAISO), and PJM Interconnection (PJM) were selected as both have extensive regulation markets and two of the major power suppliers nationwide. The main question in conducting this analysis was to determine which market would be more attractive and profitable for a potential regulation provider to invest using a Lithium ion battery. The Regulation Market Clearing Price (RMCP) for each market was extracted from the operators’ annual reports over the last six years and used as measure of investor revenue. The Levelized Cost of Energy Storage was computed for a Lithium ion battery with certain characteristics, and the investor revenue was calculated as a percent of the LCOE. Our analysis showed that although CAISO’s regulation market is showing growth in the recent years, especially in 2016 during the period of increased regulation requirement, PJM has had consistently higher RMCP values, which means the investor revenue would be higher in PJM. Our calculations show that investing a Lithium ion battery with a power rating of 10MW, and energy capacity of 5 MWh, operating at 89% efficiency for 4.8 cycles per day for 350 days in PJM is going to be economically a much smarter choice.
M.S. In Electrical Engineering, May 2017
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Title: MODERATING EFFECT OF MINDFULNESS IN THE RELATIONSHIP BETWEEN CARDIOVASCULAR DISEASE RISK FACTORS
Creator: Kim, Jeong Hye
Date: 2016, 2016-07
Description: Cardiovascular diseases (CVDs) are the leading cause of death worldwide and in the United States. Weight loss, which is associated with blood...
Show moreCardiovascular diseases (CVDs) are the leading cause of death worldwide and in the United States. Weight loss, which is associated with blood pressure and blood glucose, is widely recommended to modify the CVDs risk factors. Among various methods, mindfulness has been extensively studied in improving psychological and physical health. There is some reported evidence that mindfulness based interventions are effective in improving CVDs risk factors. However, overall results are inconclusive. Therefore, more research examining the facets of mindfulness is necessary to understand the fundamental relationship between mindfulness and CVDs risk factors to clarify the effect of mindfulness. In addition, research into whether the relationship between different risk factors is moderated by mindfulness would provide further support of the independent effect of mindfulness on physical health. The current study hypothesized that higher mindfulness skills would correlate with physical well-being. Furthermore, it was hypothesized that mindfulness will moderate a relationship between BMI and other CVDs risk factors (e.g., individuals with higher BMI classification and higher mindfulness will show lower blood pressure compared to individuals at a similar BMI with lower mindfulness). Results found that body adiposity had an inverse relationship with overall mindfulness, and two of the four facets of mindfulness (Describing and Acting with awareness). In addition, the Describing subscale had a significant moderating effect; however, the relationship between body adiposity and systolic blood pressure was stronger rather than weaker with higher Describing skills.
M.S. in Psychology, July 2016
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Title: IMPROVED METHODS FOR DETECTING PARTIALLY HYDROLYZED SOY IN FOOD
Creator: Kande, Parnavi
Date: 2016, 2016-12
Description: Methods are needed to detect soy allergens in hydrolyzed and fermented food. Project objectives included utilizing soy-specific ELISA kits and...
Show moreMethods are needed to detect soy allergens in hydrolyzed and fermented food. Project objectives included utilizing soy-specific ELISA kits and Western blot analysis to a) measure soy protein content of commercial soy sauce products; b) trace soy proteins in model soy sauces during a traditional brewing process, and c) investigate detection of soy proteins in soy protein isolate (SPI) hydrolyzed with trypsin. Twelve different soy sauce products were purchased locally. Traditionally brewed soy sauce formulated with soybeans and wheat was produced by Kikkoman in their pilot plant in Japan. Samples were obtained at the ingredient stage, after the soybeans were cooked, at the koji and moromi mash stages, and during six months of fermentation. Partially hydrolyzed SPI was prepared by treating SPI with trypsin for up to 8 h at 38 ºC. Samples were analyzed in triplicate using six soy-specific ELISA kits: 1) Neogen Veratox for Soy; 2) Ridascreen Fast Soya; 3) Elution Technologies Soy Protein; 4) Morinaga Soya; 5) AgraQuant Soy and 6) ELISA Systems Soy Protein. Western blot analysis was performed using Morinaga Soy ELISA kit antibodies. Of the 12 commercial soy sauce products, soy protein was detected in seven products at concentrations of 7.0 (1.7% CV) - 10.5 (1.8% CV) μg/g using the Elution Technologies kit, and in five samples at concentrations of 0.31 (0.6% CV) - 1.5 (0.3% CV) μg/g with the Morinaga kit. Qualitative Western blot analysis suggested the presence of beta-conglycinin in five commercial brands. Tracking soy proteins in model soy sauce by ELISA resulted >90% decrease in detection after cooking. After addition of koji culture and brine to form the moromi mash, soy protein levels were further reduced. The measured level of soy protein after one month of fermentation was 0.67 μg/g (1.1% CV) and decreased below the limit of quantitation (LOQ, 0.31 μg/g) for samples aged 2-6 months using the Morinaga assay, while other kits resulted in soy protein concentrations below the LOQ. Western blot results showed light bands of proteins for samples after 1-2 months of fermentation suggesting the presence of beta-conglycinin. Trypsin hydrolysis of SPI resulted in a gradual decrease in soy protein bands in SDS-PAGE analysis, while some ELISA kits indicated no changes in detectability of soy proteins after 10 min of hydrolysis. Overall, the results of this study indicate that heating, hydrolysis and fermentation processes can have substantial effects on the detection of soy proteins in food.
M.S. in Food Safety and Technology, December 2016
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Title: MINIMUM COST DESIGN OF LOGISTICS NETWORKS WITH EXPEDITED SHIPPING SERVICES
Creator: Poghosyan, Karen
Date: 2014, 2014-12
Description: This study analyzes and designs a logistics network for the distribution of four brands of passenger cars in the Great Lakes region. The study...
Show moreThis study analyzes and designs a logistics network for the distribution of four brands of passenger cars in the Great Lakes region. The study evaluates four types of distribution scenarios. Alternative 1 analyzes direct shipment method with only truck transportation mode from one distribution center located in the Chicago city to the cities in the Great Lakes region. Second alternative analyzes direct distribution method using multimodal transportation modes (railway and truck) from one distribution center to the cities included in this project. Third alternative analyzes peddling distribution method with only truck transportation mode from one warehouse to the project cities and the fourth alternative analyzes car distribution using direct shipment method with only truck transportation mode from two warehouses, where the main warehouse is located in Chicago city and the second warehouse is located in Indianapolis city. The analyses are conducted in order to determine the most cost-effective scenario for passenger car distribution in the Great Lakes region. The results of the study show that the most cost-effective scenario for passenger car distribution in the Great Lakes region includes using direct shipment method with multimodal transportation mode having one warehouse. However, this scenario has many uncovered sections such as we assumed that the warehouse and all destinations are located near to the railway yard and we do not need to transport cars from warehouse to the railway yard or from railway yard to the dealer by car huller truck/trailer. But in most of the time a railway yard and distribution center or a car dealership is not located in the same place or close to each other which in reality could increase the total cost for the logistics network. The second optimal cost provides the Alternative 1, which uses direct shipment method with only truck transportation mode and having one warehouse. This scenario is more practical and possible to use in reality without having significant changes in the total cost.
M.S. in Civil, Architectural and Environmental Engineering, December 2014
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Title: IRRITABILITY IN CHILDREN: SAME AS FRUSTRATION AND ANGER?
Creator: Kozy, Karyn Brasky
Date: 2013, 2013-12
Description: The primary aims of this study were four-fold. The first aim was to examine which of the three alternative models of irritability provided a...
Show moreThe primary aims of this study were four-fold. The first aim was to examine which of the three alternative models of irritability provided a better fit to the data. The second aim was to further refine the model of irritability by examining the gender and age invariance of the best-fitting models. After establishing which model showed the best fit, the third aim was to empirically examine the reliability and validity of the irritability scale that included items from both temperament and psychopathology scales. Finally, the fourth aim was to examine the rank-order stability and mean-levels of irritability between the ages of 4 and 6. Participants included a diverse, community sample of 796 children and their parents. Irritability, frustration, and anger were measured by selected items from temperament and psychopathology scales, including the Children’s Behavior Questionnaire (CBQ; Rothbart et al., 2001), Child Symptom Inventory (CSI; Gadow & Sprafkin, 1994, 1997), and Eyberg Behavior Inventory (ECBI; Eyberg & Pincus, 1999). Results indicate that the three-factor and two-factor measurement models were viable, alternative models at age 4. Contrary to expectation, neither the three-factor nor the twofactor models were invariant for both genders combined, or between the ages of 4 and 6. Based on the definition of irritability in the three-factor model, the irritability scale demonstrated adequate internal consistency, convergent validity, and divergent validity. Finally, the rank-order stability of irritability was in the moderate range during the period from preschool through kindergarten and formal school entry, but mean-levels of irritability did not differ across time. Implications of the findings and suggestions for future research are discussed.
PH.D in Psychology, December 2013
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Title: ROBUST OPTIMIZATION OF UNIT COMMITMENT PROBLEM WITH RENEWABLE RESOURCES AND ELECTRICAL ENERGY STORAGE
Creator: Kashyap, Prakash
Date: 2016, 2016-12
Description: The Chinese proverb |\To be uncertain is to be uncomfortable, but to be cer- tain is to be ridiculous" |mention in the preface of the book...
Show moreThe Chinese proverb |\To be uncertain is to be uncomfortable, but to be cer- tain is to be ridiculous" |mention in the preface of the book Robust Optimization by Aharon Ben-Tal, Laurent El Ghaoui and Arkadi Nemirovski, truly capture the cer- tainty of uncertainty in every walk of life. However, it is human endeavor to manage uncertainty by properly engineered system. Power system is no exception. Uncer- tainty with load forecasting and contingencies such as generator and/or transmission line outages impose reliability and security issue with power system operation. In wholesale market, tools like spinning reserve and non-spinning reserve are used by ISO/RTO to mitigate severe consequences of such uncertainties. With increased share of highly volatile renewable energy resources such as wind and solar power, price-based demand response and electric vehicle charging station, uncertainty in power system operation is going to be further aggravated. A scenario based stochastic approach instead of system reserve based deterministic approach is considered another solution to the problem. However, scenario based stochastic solution may miss some critical scenarios. Secondly, we may need a large number of scenarios to get a su ciently reliable solution. In recent years, robust optimization based security constrained economic dis- patch (SCED) and security constrained unit commitment (SCUC) have been explored by several researchers. This thesis explores implementation of robust optimization for secure and economical operation of power system in presence of renewable energy resources (RES) and electrical energy storages (EES).
M.S. in Electrical Engineering, December 2016
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Title: CROSS-ETHNIC VARIATION IN THE RELATION BETWEEN PARENT AND CHILD BEHAVIORS AND YOUNG CHILDREN’S ACADEMIC AND SOCIAL FUNCTIONING
Creator: Bae, Hyo
Date: 2011-04-20, 2011-05
Description: The aim of this study was to determine if there is cross-ethnic variation in the relationships between parent behaviors, child behaviors, and...
Show moreThe aim of this study was to determine if there is cross-ethnic variation in the relationships between parent behaviors, child behaviors, and young children’s academic and social functioning. Participants included 96 African American, 117 Hispanic, and 395 White 5-year-old children and their parents. Self-reported parenting (Support/Engagement and Hostility/Coercion) was assessed with the Parent Behavior Inventory. Observed parent (Scaffolding) and child behaviors (Engagement/Persistence) were assessed using the Three Boxes Task videotaped parent-child interaction paradigm. Children’s academic skills were measured with three subtests of the Woodcock-Johnson Tests of Achievement-3rd Edition (Letter-Word Identification, Passage Comprehension, and Quantitative Concepts), and their social skills were measured with the Social Skills Rating System. Results of moderated regression analyses indicated that there were no direct effects of parenting on academic achievement, but that child Engagement/Persistence was related to academic achievement. With regard to social skills, Support/Engagement was related to Cooperation, Assertion, Responsibility, and Self-Control, while Hostility/Coercion was related to Cooperation, Responsibility, and Self-Control. Scaffolding was not directly related to social skills. Also, these analyses showed that the majority of these relationships were invariant across ethnic groups, with only a few significant interaction effects. Specifically, higher levels of Scaffolding were related to higher reading scores for African American children, while Scaffolding was not related to reading for White children. Although higher levels of Hostility/Coercion were related to lower reading scores for White children, this relationship was not significant for Hispanic children. Higher levels of Scaffolding were related to higher math scores for African American children. For White children, however, higher levels of Scaffolding were related to lower math scores. There were no ethnic differences in the relation between parent and child behaviors and social skills. Finally, results indicated that Scaffolding was indirectly related to academic and social functioning through Engagement/Persistence, and there was no ethnic variation in these relationships across African American, Hispanic, and White children. The implications of these findings and future directions for research are discussed.
Ph.D. in Psychology, May 2011.
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Title: PROTEOLYTIC STABILITY OF FIBRONECTIN CONJUGATED TO POLYETHYLENE GLYCOL: EFFECT OF PEG LENGTH TO CYSTEINE RESIDUES
Creator: Hekmatfar, Sogol
Date: 2013, 2013-07
Description: Fibronectin (FN) is an essential protein of the extracellular matrix (ECM) needed in wound healing. In chronic wounds, the high levels of...
Show moreFibronectin (FN) is an essential protein of the extracellular matrix (ECM) needed in wound healing. In chronic wounds, the high levels of protease in the wound bed lead to excessive degradation of fibronectin, which delays the healing process. Developing a proteolytically stable and functionally active form of FN is the main purpose of this research. Conjugating of proteins to polyethylene glycol (PEG) or PEGylating proteins showed more proteolytic stability than native FN degradation without perturbing their activity. The goal of this study was to compare the proteolysis of native and PEGylated fibronectin with different PEG length. Fibronectin was purified from human blood plasma and conjugated to PEG Diacrylate (PEGDA) and other types of PEG to yield the PEGylated human plasma fibronectin (PEG-HPFN). α-chymotrypsin and neutrophil elastase were used as digestion enzyme during degradation reaction. The proteolysis reaction was stopped at different time points with protein inhibitor phenylmethanesulfonylfluoride (PMSF). The samples were analyzed by SDS-PAGE followed by silver staining or immunblotting with antibodies specific to human fibronectin. Densitometric analyses of the polyacrylamide gels or the blots demonstrated that PEG-HPFN was more stable than native HPFN. The results demonstrate that PEGylation is a robust approach for stabilizing fibronectin. Future studies into activity of PEGylated proteins as well as the role of PEGylation factors such as extent of PEGylation or PEG length on activity will provide novel strategies of mitigating fibronectin degradation in chronic wounds.
M.S. in Chemical Engineering, July 2013
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Title: AN ENERGY-PRESERVING SCHEME FOR THE POISSON-NERNST-PLANCK EQUATIONS
Creator: Kabre, Julienne
Date: 2017, 2017-07
Description: Transport of ionic particles is ubiquitous in all biology. The Poisson-Nernst- Planck (PNP) equations have recently been used to describe the...
Show moreTransport of ionic particles is ubiquitous in all biology. The Poisson-Nernst- Planck (PNP) equations have recently been used to describe the dynamics of ion transport through biological ion channels (besides being widely employed in semiconductor industry). This dissertation is about the design of a numerical scheme to solve the PNP equations that preserves exactly (up to roundoff error) a discretized form of the energy dynamics of the system. The proposed finite difference scheme is of second-order accurate in both space and time. Comparisons are made between this energy dynamics preserving scheme and a standard finite difference scheme, showing a difference in satisfying the energy law. Numerical results are presented for validating the orders of convergence in both time and space of the new scheme for the PNP system. The energy preserving scheme presented here is one dimensional in space. A highlight of an extension to the multi-dimensional case is shown.
Ph.D. in Applied Mathematics, July 2017
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Title: DYNAMICS OF VESICLES IN VISCOUS FLUID
Creator: Liu, Kai
Date: 2014, 2014-12
Description: Modeling vesicle dynamics involves a complicated moving boundary problem where uids, thermal uctuations, and vesicle morphology are intimately...
Show moreModeling vesicle dynamics involves a complicated moving boundary problem where uids, thermal uctuations, and vesicle morphology are intimately coupled. In this thesis, we study the dynamics of a two-dimensional membrane in linear viscous ows. In the asymptotic analysis section, we derive deterministic and stochastic equations describing the motion of a slightly perturbed membrane interface. Using a 2nd order Runge-Kutta method, we solve these equations numerically, and explain the formation and development of wrinkling patterns. We then develop a boundary integral method and an immersed boundary method for simulating the nonlinear wrinkling dynamics of a homogenous vesicle in viscous ows. The nonlinear results agree with the asymptotic theory for a nearly circular vesicle, and also agree with experimental results for an elongated vesicle. Using a stochastic immersed boundary method, we investigate the e ects of thermal uctuations in vesicle dynamics. Comparing with the deterministic results, thermal uctuation can lead to the development of odd modes and asymmetric wrinkles. Finally, we investigate the nonlinear wrinkling dynamics of a multi-component vesicle. The model includes a 4th order Cahn-Hilliard type equation describing the phase transitions on the vesicle surface. We nd that for an elongated vesicle with large excess arc length, the inhomogeneous bending introduces nontrivial asymmetric wrinkling and buckling dynamics.
Ph.D. in Applied Mathematics, December 2014
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Title: CONTROL OF DOUBLY-FED INDUCTION GENERATOR FOR WIND APPLICATION
Creator: Guo, Jing
Date: 2012-05-03, 2012-05
Description: With growing concerns over environmental pollution and globe warming, renewable energy has received considerable attention as an alternative...
Show moreWith growing concerns over environmental pollution and globe warming, renewable energy has received considerable attention as an alternative energy resource of electricity production. Because of the immense potential of wind energy on the earth, wind power generation has gained significant popularity over recent years. From this research, it has been concluded that there is a constant need to reduce the size and rating of power electronic converters, improve efficiency of the electromechanical system and make the system more reliable by eliminating the gearbox. This thesis analyzes a doubly fed induction generator (DFIG) drive system for distributed wind generation systems. The structure of a doubly fed induction generator is similar to that of an induction generator. To illustrate the operation principle and control strategy of a DFIG clearly, the fundamentals and control principle of an induction generator have been discussed. For DFIG control, two closed control loops are designed-active power control loop and rotor speed control loop; and they can be switched between each other. By utilizing active power control loop, the output power of the system can be regulated to meet different customer requirements and their dependence on grid electricity can be eliminated, therefore the cost and the power loss on transmission lines can be reduced. On the other hand, by switching to the speed control loop, the system can extract maximum power at different wind speeds, and any extra power can either be stored or sold to the utility for profit. To validate the proposed concept, Finite Element Analysis (FEA) models of a doubly fed induction generator and an induction generator have been built and simulated using the software Magnet®; furthermore, the control systems of these two generators are implemented and simulated in a Matlab/Simulink environment. Finally, a Magnet and Matlab/Simulink co-simulation has been performed for the DFIG. By analyzing the simulation results, the differences between the doubly-fed induction generator and an induction generator have been demonstrated.
M.S. in Electrical Engineering, May 2012
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Title: Predictive energy efficient control framework for connected and automated vehicles in heterogeneous traffic environments
Creator: Vellamattathil Baby, Tinu
Date: 2023
Description: Within the automotive industry, there is a significant emphasis on enhancing fuel efficiency and mobility, and reducing emissions. In this...
Show moreWithin the automotive industry, there is a significant emphasis on enhancing fuel efficiency and mobility, and reducing emissions. In this context, connected and automated vehicles (CAVs) represent a significant advancement, as they can optimize their acceleration pattern to improve their fuel efficiency. However, when CAVs coexist with human-driven vehicles (HDVs) on the road, suboptimal conditions arise, which adversely affect the performance of CAVs. This research analyzes the automation capabilities of production vehicles to identify scenarios where their performance is suboptimal, and proposes a merge-aware modification of adaptive cruise control (ACC) method for highway merging situations. The proposed algorithm addresses the issue of sudden gap and velocity changes in relation to the preceding vehicle, thereby reducing substantial braking during merging events, resulting in improved energy efficiency. This research also presents a data-driven model for predicting the velocity and position of the preceding vehicle, as well as a robust model predictive control (MPC) strategy that optimizes fuel consumption while considering prediction inaccuracies. Another focus of this research is a novel suggestion-based control framework in interactive mixed traffic environments leveraging the emerging connectivity between vehicles and with infrastructure. It is based on MPC to optimize the fuel efficiency of CAVs in heterogeneous or mixed traffic environments (i.e., including both CAVs and HDVs). In this suggestion-based control framework, the CAVs are considered to provide non-binding velocity and lane change suggestions to the HDVs to follow to improve the fuel efficiency of both the CAVs and the HDVs. To achieve this, the host CAV must devise its own fuel-efficient control solution and determine the recommendations to convey to its preceding HDV. It is assumed that the CAVs can communicate with the HDVs via Vehicle to Vehicle (V2V) communication, while the Signal Phase and Timing (SPaT) information is accessed via Vehicle-to- Infrastructure (V2I) communication. These velocity suggestions remain constant for a predefined period, allowing the driver to adjust their speed accordingly. It is also considered that the suggestions are non binding, i.e., a driver can choose not to follow the suggested velocity. For this control framework to function, we present a velocity prediction model based on experimental data that captures the response of a HDV to different suggested velocities, and a robust approach to ensure collision avoidance. The velocity prediction’s accuracy is also validated with the experimental data (on a table-top drive simulator), and the results are presented. In cases of low CAV penetration, a CAV needs to provide suggestions to multiple surrounding HDVs and incorporating the suggestions to all the HDVs as decision variables to the optimal control problem can be computationally expensive. Hence, a suggestion-based hierarchical energy efficient control framework is also proposed in which a CAV takes into account the interactive nature of the environment by jointly planning its own trajectory and evaluating the suggestions to the surrounding HDVs. Joint planning requires solving the problem in joint state- and action-space, and this research develops a Monte Carlo Tree Search (MCTS)-based trajectory planning approach for the CAV. Since the joint action- and state-space grows exponentially with the number of agents and can be computationally expensive, an adaptive action-space is proposed through pruning the action-space of each agent so that the actions resulting in unsafe trajectories are eliminated. The trajectory planning approach is followed by a low-level model predictive control (MPC)-based motion controller, which aims at tracking the reference trajectory in an optimal fashion. Simulation studies demonstrate the proposed control strategy’s efficacy compared to existing baseline methods.
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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: Retrospective Quantitative T1 Imaging to Examine Characteristics of Multiple Sclerosis Lesions
Creator: Young, Griffin James
Date: 2024
Description: Quantitative MRI plays an essential role in assessing tissue abnormality and diseaseprogression in multiple sclerosis (MS). Specifically, T1...
Show moreQuantitative MRI plays an essential role in assessing tissue abnormality and diseaseprogression in multiple sclerosis (MS). Specifically, T1 relaxometry is gaining popularity as elevated T1 values have been shown to correlate with increased inflammation, demyelination, and gliosis. The predominant issue is that relaxometry requires parametric mapping through advanced imaging techniques not commonly included in standard clinical protocols. This leaves an information gap in large clinical datasets from which quantitative mapping could have been performed. We introduce T1-REQUIRE, a retrospective T1 mapping method that approximates T1 values from a single T1-weighted MR image. This method has already been shown to be accurate within 10% of a clinically available reference standard in healthy controls but will be further validated in MS cohorts. We also further aim to determine T1-REQUIRE’s statistical significance as a unique biomarker for the assessment of MS lesions as they relate to clinical disability and disease burden. A 14-subject comparison between T1-REQUIRE maps derived from 3D T1 weighted turbo field echoes (3D T1w TFE) and an inversion-recovery fast field echo (IRFFE) revealed a whole-brain voxel-wise Pearson’s correlation of r = 0.89 (p < 0.001) and mean bias of 3.99%. In MS white matter lesions, r = 0.81, R2 = 0.65 (p < 0.001, N = 159), bias = 10.07%, and in normal appearing white matter (NAWM), r = 0.82, R 2 = 0.67 (p < 0.001), bias = 9.48%. Mean lesional T1-REQUIRE and MTR correlated significantly (r = -0.68, p < 0.001, N = 587) similar to previously published literature. Median lesional MTR correlated significantly with EDSS (rho = -0.34, p = 0.037), and lesional T1-REQUIRE exhibited xiii significant correlations with global brain tissue atrophy as measured by brain parenchymal fraction (BPF) (r = -0.41, p = 0.010, N = 38). Multivariate linear regressions between T1- REQUIRE NAWM provided meaningful statistical relationships with EDSS (β = 0.03, p = 0.027, N = 38), as well as did mean MTR values in the Thalamus (β = -0.27, p = 0.037, N = 38). A new spoiled gradient echo variation of T1-REQUIRE was assessed as a proof of concept in a small 5-subject MS cohort compared with IR-FFE T1 maps, with a whole brain voxel-wise correlation of r = 0.88, R2 = 0.77 (p < 0.001), and Bias = 0.19%. Lesional T1 comparisons reached a correlation of r = 0.75, R2 = 0.56 (p < 0.001, N = 42), and Bias = 10.81%. The significance of these findings means that there is the potential to provide supplementary quantitative information in clinical datasets where quantitative protocols were not implemented. Large MS data repositories previously only containing structural T1 weighted images now may be used in big data relaxometric studies with the potential to lead to new findings in newly uncovered datasets. Furthermore, T1-REQUIRE has the potential for immediate use in clinics where standard T1 mapping sequences aren’t able to be readily implemented.
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Title: Extremal and Enumerative Problems on DP-Coloring of Graphs
Creator: Sharma, Gunjan
Date: 2024
Description: Graph coloring is the mathematical model for studying problems related to conflict-free allocation of resources. DP-coloring (also known as...
Show moreGraph coloring is the mathematical model for studying problems related to conflict-free allocation of resources. DP-coloring (also known as correspondence coloring) of graphs is a vast generalization of classic graph coloring, and many more concepts of colorings studied in the past 150+ years. We study problems in DP-coloring of graphs that combine questions and ideas from extremal, structural, probabilistic, and enumerative aspects of graph coloring. In particular, we study (i) DP-coloring Cartesian products of graphs using the DP-color function, the DP coloring counterpart of the Chromatic polynomial, and robust criticality, a new notion of graph criticality; (ii) Shameful conjecture on the mean number of colors used in a graph coloring, in the context of list coloring and DP-coloring; and (iii) asymptotic bounds on the difference between the chromatic polynomial and the DP color function, as well as the difference between the dual DP color function and the chromatic polynomial, in terms of the cycle structure of a graph. These results respectively give an upper bound and a lower bound on the chromatic polynomial in terms of DP colorings of a graph.
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Title: Agency and Pathway Thinking as Mediators of The Relationship Between Caregiver Burden And Life Satisfaction Among Family Caregivers Of People With Parkinson’s Disease: An Application Of Snyder’s Hope Theory
Creator: Springer, Jessica Gabrielle
Date: 2024
Description: In the United States, there are 47.9 million caregivers providing care to family members with disabilities. Those providing care to someone...
Show moreIn the United States, there are 47.9 million caregivers providing care to family members with disabilities. Those providing care to someone who has Parkinson’s Disease (PD), a complex degenerative movement disorder, may have a unique caregiving experience, given that disease-related factors (e.g. motor and non-motor symptoms) can contribute to worsening caregiver burden and life satisfactions (LS). PD has an increasing incidence of 90,000 new cases per year, likely resulting in an increased need for caregivers. Caregiving research frequently focuses on the mediators between caregiver burden and LS including social support, coping skills, and appraisals. Research that has specifically focused on caregivers of people with PD (Pw/PD) is significantly limited. Hope is a “positive motivational characteristic comprised of agency and pathways thinking that can help facilitate drive towards one’s goal while also serving as a buffer against negative events” (Snyder et al.,1991). The goal of this study is to understand Snyder’s hope theory as it relates to caregiver burden and LS for caregivers of Pw/PD. Specifically, we hypothesized that (a) caregiver burden will be negatively correlated with agency thinking, pathways thinking, and LS among caregivers of Pw/PD. In addition, pathways thinking, and agency thinking will be positively associated with LS, and (b) agency thinking, and pathways thinking will mediate the relationship between caregiver burden and LS among caregivers of Pw/PD. The study sample consisted of 249 caregivers of Pw/PD who completed an online anonymous questionnaire. Correlations between agency and pathways thinking, LS, caregiver burden, and sociodemographic factors were evaluated. A parallel mediation analysis was run to evaluate the mediating roles of pathways and agency thinking in the relationship between caregiver burden and LS. Results indicated that LS was significantly and negatively correlated with caregiver burden. LS was significantly and positively correlated with both pathways and agency thinking. Pathways thinking had no indirect effect on the relationship of caregiver burden on LS. Agency thinking had a negative, indirect effect on the relationship suggesting that agency thinking partially mediated the relationship between caregiver burden and LS. Clinical implications and future directions are discussed.
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Title: Predictive energy efficient control framework for connected and automated vehicles in heterogeneous traffic environments
Creator: Vellamattathil Baby, Tinu
Date: 2023
Description: Within the automotive industry, there is a significant emphasis on enhancing fuel efficiency and mobility, and reducing emissions. In this...
Show moreWithin the automotive industry, there is a significant emphasis on enhancing fuel efficiency and mobility, and reducing emissions. In this context, connected and automated vehicles (CAVs) represent a significant advancement, as they can optimize their acceleration pattern to improve their fuel efficiency. However, when CAVs coexist with human-driven vehicles (HDVs) on the road, suboptimal conditions arise, which adversely affect the performance of CAVs. This research analyzes the automation capabilities of production vehicles to identify scenarios where their performance is suboptimal, and proposes a merge-aware modification of adaptive cruise control (ACC) method for highway merging situations. The proposed algorithm addresses the issue of sudden gap and velocity changes in relation to the preceding vehicle, thereby reducing substantial braking during merging events, resulting in improved energy efficiency. This research also presents a data-driven model for predicting the velocity and position of the preceding vehicle, as well as a robust model predictive control (MPC) strategy that optimizes fuel consumption while considering prediction inaccuracies. Another focus of this research is a novel suggestion-based control framework in interactive mixed traffic environments leveraging the emerging connectivity between vehicles and with infrastructure. It is based on MPC to optimize the fuel efficiency of CAVs in heterogeneous or mixed traffic environments (i.e., including both CAVs and HDVs). In this suggestion-based control framework, the CAVs are considered to provide non-binding velocity and lane change suggestions to the HDVs to follow to improve the fuel efficiency of both the CAVs and the HDVs. To achieve this, the host CAV must devise its own fuel-efficient control solution and determine the recommendations to convey to its preceding HDV. It is assumed that the CAVs can communicate with the HDVs via Vehicle to Vehicle (V2V) communication, while the Signal Phase and Timing (SPaT) information is accessed via Vehicle-to- Infrastructure (V2I) communication. These velocity suggestions remain constant for a predefined period, allowing the driver to adjust their speed accordingly. It is also considered that the suggestions are non binding, i.e., a driver can choose not to follow the suggested velocity. For this control framework to function, we present a velocity prediction model based on experimental data that captures the response of a HDV to different suggested velocities, and a robust approach to ensure collision avoidance. The velocity prediction’s accuracy is also validated with the experimental data (on a table-top drive simulator), and the results are presented. In cases of low CAV penetration, a CAV needs to provide suggestions to multiple surrounding HDVs and incorporating the suggestions to all the HDVs as decision variables to the optimal control problem can be computationally expensive. Hence, a suggestion-based hierarchical energy efficient control framework is also proposed in which a CAV takes into account the interactive nature of the environment by jointly planning its own trajectory and evaluating the suggestions to the surrounding HDVs. Joint planning requires solving the problem in joint state- and action-space, and this research develops a Monte Carlo Tree Search (MCTS)-based trajectory planning approach for the CAV. Since the joint action- and state-space grows exponentially with the number of agents and can be computationally expensive, an adaptive action-space is proposed through pruning the action-space of each agent so that the actions resulting in unsafe trajectories are eliminated. The trajectory planning approach is followed by a low-level model predictive control (MPC)-based motion controller, which aims at tracking the reference trajectory in an optimal fashion. Simulation studies demonstrate the proposed control strategy’s efficacy compared to existing baseline methods.
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Title: Estimation of Platinum Oxide Degradation in Proton Exchange Membrane Fuel Cells
Creator: Ahmed, Niyaz Afnan
Date: 2024
Description: The performance and durability of Proton Exchange Membrane Fuel Cells (PEMFCs) can be significantly hampered due to the degradation of the...
Show moreThe performance and durability of Proton Exchange Membrane Fuel Cells (PEMFCs) can be significantly hampered due to the degradation of the platinum catalyst. The production of platinum oxide is a major cause of the degradation of the fuel cell system, negatively affecting its performance and durability. In order to predict and prevent this degradation, this research examines a novel method to estimate degradation due to platinum oxide formation and predict the level of platinum oxide coverage over time. Mechanisms of platinum oxide formation are outlined and two methods are compared for platinum oxide estimation. Linear regression and two Artificial Neural Network (ANN) models, including a Recurrent Neural Network (RNN) and Feed-forward Back Propagation Neural Network (FFBPNN), are compared for estimation. The estimation model takes into account the influence of cell temperature and relative humidity.Evaluation of relative errors (RE) and root mean square error (RMSE) illustrates the superior performance of RNN in contrast to GT-Suite and FFBPNN. However, both RNN and GT-Suite showcase an average error rate below 5% while the FFBPNN had a higher error rate of approximately 7%. The RMSE of RNN shows mostly less compared to FFBPNN and GT-Suite, however, at 50% training data, GT-Suite shows lowest RMSE. These findings indicate that GT-Suite can be a valuable tool for estimating platinum oxide in fuel cells with a relatively low RE, but the RNN model may be more suitable for real-time estimation of platinum oxide degradation in PEM fuel cells, due to its accurate predictions and shorter computational time. This comprehensive approach provides crucial insights for optimizing fuel cell efficiency and implementing effective maintenance strategies.
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