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Title: AN INTEGRATED RESOURCE MANAGEMENT AND SCHEDULING FRAMEWORK FOR PRODUCTION SUPERCOMPUTERS
Creator: Tang, Wei
Date: 2012-07-16, 2012-07
Description: Resource management and job scheduling is a crucial task on large-scale computing systems. Despite years of research on resource management...
Show moreResource management and job scheduling is a crucial task on large-scale computing systems. Despite years of research on resource management and scheduling, it has not kept pace with modern changes and technology trends. The study of this thesis is motivated by emerging issues observed in current production supercomputers, caused by reasons such as human behaviors, application characteristics, and increasing system complexity. Specifically, users tend to provide inaccurate parameters for their jobs which are dependent by the scheduler; system owners have diverse goals which are always conflicting with each other. Also, workload characteristics on production supercomputers keep changing unpredictably, making it hard to achieve a sustainable scheduling performance since scheduling policies are largely dependent on workload characteristics. Further, increasing hardware complexity causes system issues and leads to new demands. For example, issues such as node fragmentation, failure interruption, power consumption, and I/O overhead have become common in large-scale systems. Existing resource management systems lack the support for these issues and demands. In this study, we present an integrated resource management and scheduling framework, aiming at addressing emerging issues and challenges in resource management for large-scale production supercomputers. We have designed a set of new schemes, including job parameter prediction, adaptive metric-aware job scheduling, cost-aware job scheduling, and multi-domain job coscheduling. We have implemented these approaches in the production resource manager Cobalt, and evaluated them with real job traces from production supercomputers such as the Blue Gene/P system at Argonne National Laboratory. Experimental results show our schemes can effectively improve job scheduling regarding both user satisfaction and system utilization.
Ph.D. in Computer Science, July 2012
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Title: EVALUATION OF TALL OFFICE BUILDING FORM TO ENHANCE WIND ENERGY PRODUCTION IN BUILDING INTEGRATED WIND TURBINE, A PERFORMANCE BASED APPROACH FOR EARLY DESIGN STAGE
Creator: Abdolhossein Pour, Farid
Date: 2014, 2014-12
Description: A newly emerging way to promote sustainability in the built environment is through the incorporation of wind power within buildings, resulting...
Show moreA newly emerging way to promote sustainability in the built environment is through the incorporation of wind power within buildings, resulting in minimum transmission losses (distributed generation). However, the effectiveness of the proposed solutions are seriously dependent on early integration with the architectural design process. Wind power is considered a potential renewable energy source in tall buildings due to the possibility of accessing greater wind velocities at higher altitudes. In addition, airflow patterns around buildings are considerably influenced by a buildings’ geometric characteristics. Hypothetically, proper modification of building form can turn this unstructured phenomenon in to a massive concentrator effect, capable of boosting power production in tall buildings with an integrated wind turbine (BIWT). These aerodynamic modifications are typically evaluated via CFD simulation or wind tunnel testing. However, these methods are too expensive and time-consuming to analyze all annual fluctuations of local wind regimes (velocity, direction, and density) and is therefore inappropriate for use in early design stages when architectural concepts quickly evolve. As a result, existing wind analysis techniques are often used under simplified conditions (steady state analysis, single velocity, and angle). This approach simply disregards the wide variety of other criteria influencing “BIWT annual energy output” including fluctuations of local wind regimes, and surrounding urban terrain roughness. This research seeks to address the issues indicated above, and proposes a performance based parametric design tool, primarily for the early design stages when architectural concepts evolve rapidly. The automated output delivers real time assessment of BIWT potential energy enhancement for each alternation of the concept, as well as analysis of multiple BIWT typologies simultaneously. The parametric tool employs hourly weather data, different terrain condition mathematical models, and two databases of CFD measurements to approximate annual energy enhancement as result of BIWT geometrical transformations. The tool develops a decision mechanism to find the best BIWT typology and optimum angle, based on the long-term local climatic trends and adjacent terrain context. The outcome of this dissertation is an automated parametric tool which addresses all above indicated difficulties associated with incorporation of current wind analysis method and the architectural design process of BIWT.
Ph.D. in Architecture, December 2014
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Title: MARKET DOMINANT PLUG-IN HYBRID ELECTRIC VEHICLES OPTIMAL CONTROL FOR MINIMUM CHARGING COST AND V2G REGULATION SERVICE
Creator: Li, Zhihao
Date: 2012-07-23, 2012-07
Description: Plug-in hybrid electric vehicles (PHEVs) share the characteristics of hybrid electric vehicles (HEVs) and electric vehicles (EVs), employing...
Show morePlug-in hybrid electric vehicles (PHEVs) share the characteristics of hybrid electric vehicles (HEVs) and electric vehicles (EVs), employing electric motors and internal combustion engines (ICEs) for propulsion as well as large capacity batteries for energy storage. With ICEs and fuel tank on board, PHEVs do not have the range limitations posed by EVs; large capacity battery promises long distance all-electric range (AER) and fuel efficiency improvement. PHEVs will play a vital role in future as a sustainable transportation system, promising for environment, energy solution, and economy. It is estimated that by 2015, the total number of PHEVs in the world will be approximately 1.7 million with the U.S. marking leading the industry with about one million PHEVs. Growing penetration of PHEVs will place significant impacts on the grid, either as additional electric loads or potential assets which could provide various vehicleto- grid (V2G) services. There are four potential grid services that PHEVs can provide: base load generation, peak load shaving, spinning reserve, and regulation. PHEVs are not competitive in base load or peak load markets due to limited battery capacities. In addition, PHEVs are not real generating units and the energy stored in batteries is absorbed from grid. V2G support is taken into account as frequency regulation by participating in ancillary service markets. However, if implemented without proper control, large scale PHEVs will cause increases of peak load and destabilize the grid. This paper proposes an optimization strategy to maximize V2G profits as well as to minimize charging costs. The optimization strategy is based on a forecast of future electricity price for both residential electricity and regulation market. Due to the stochastic nature of electricity price, final prices cannot be deterministically calculated. Therefore, the addressed problem is solved by stochastic dynamic programming to find the economically optimal solution with price uncertainties. Constraints caused by vehicle utilization as well as technical limitations are taken into account. Additional costs arising from discharging batteries for ancillary service can be partially or completely compensated by V2G profits. In this Ph.D. research work, economical impacts of PHEV fleet are examined in Pennsylvania Jersey Maryland (PJM) regulation market. The major contributions of this paper are: Mathematically model the optimal control of PHEV with comprehensive transition function and cost function; A full study of battery life and cost that considers different ageing factors; A stochastic study of uncertainty and volatility in electricity price; Include battery degradation and price uncertainty in the comprehensive function for optimal control.
Ph.D. in Electrical Engineering, July 2012
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Title: METHODOLOGY FOR URBAN AREA SNOW REMOVAL USING NEW MACHINE AND PERFORMANCE-BASED ANALYSIS
Creator: Neishapouri, Mohammad
Date: 2015, 2015-12
Description: The need for alternative methods that facilitate removal of snow on urban streets with minimal pavement and bridge damages, vehicles...
Show moreThe need for alternative methods that facilitate removal of snow on urban streets with minimal pavement and bridge damages, vehicles corrosions, and environmental impacts due to use of chemicals and salts has been growing over time. Conversely, this issue has not been thoroughly investigated. This is particularly true for large urban areas where the snow removal machine and background traffic share already congested streets. In this research, a new methodology is introduced for effectively managing snow removal that involves new machine and performance-based analysis. The new machine aims to melt snow and ice using technically adequate mechanical system including special engine, heat pumps and very fast ventilation pumps in order to suck and discharge water from pavement surface to road sides. The performance-based analysis employs a life cycle cost analysis approach to estimate reductions in expenditures to pavements and bridges, and vehicle corrosions of background traffic as a result of using new machine for snow melting instead of using chemicals and salts; and an optimization model for effective dispatching of new machine across a large area, leading to a significant level of travel timing savings to the background traffic owning to shorter duration oftravel way closures. The proposed methodology is implemented in a computational study to examine the current snow removal programs in the city of Chicago for a typical winter day involving moderate and severe snowfalls that correspond to its 50 percent and 100 percent programs for filed dispatching one-half and all snow plow trucks. Compared with the use of snow removal trucks coupled with chemicals and salts, the use of new machine could result in better equivalent annualized savings as benefits component and less amount of cost components which cause the project implementation has benefit to cost ratio Xl11The need for alternative methods that facilitate removal of snow on urban streets with minimal pavement and bridge damages, vehicles corrosions, and environmental impacts due to use of chemicals and salts has been growing over time. Conversely, this issue has not been thoroughly investigated. This is particularly true for large urban areas where the snow removal machine and background traffic share already congested streets. In this research, a new methodology is introduced for effectively managing snow removal that involves new machine and performance-based analysis. The new machine aims to melt snow and ice using technically adequate mechanical system including special engine, heat pumps and very fast ventilation pumps in order to suck and discharge water from pavement surface to road sides. The performance-based analysis employs a life cycle cost analysis approach to estimate reductions in expenditures to pavements and bridges, and vehicle corrosions of background traffic as a result of using new machine for snow melting instead of using chemicals and salts; and an optimization model for effective dispatching of new machine across a large area, leading to a significant level of travel timing savings to the background traffic owning to shorter duration oftravel way closures. The proposed methodology is implemented in a computational study to examine the current snow removal programs in the city of Chicago for a typical winter day involving moderate and severe snowfalls that correspond to its 50 percent and 100 percent programs for filed dispatching one-half and all snow plow trucks. Compared with the use of snow removal trucks coupled with chemicals and salts, the use of new machine could result in better equivalent annualized savings as benefits component and less amount of cost components which cause the project implementation has benefit to cost ratio respectively 2.15 and 2 by CPI analysis and 3 and 3.04 by CCI analysis. Compared with the current practice of filed dispatching of snow plow trucks or new machine for snow removal, the optimization model for vehicle dispatching could further improve the snow removal productivity by 2-4 percent for the 100 percent program and 3-8 percent for the 50 percent program, respectively.
Ph.D. in Civil Engineering, December 2015
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Title: POSTTRAUMATIC GROWTH AMONG HIV-SEROPOSITIVE ADOLESCENTS AND YOUNG ADULTS
Creator: Niel, Kristin A.
Date: 2016, 2016-12
Description: An estimated 1,218,400 individuals in the United States were living with HIV/AIDS in 2014 (CDC, November 2015). In addition, 9,731 youth...
Show moreAn estimated 1,218,400 individuals in the United States were living with HIV/AIDS in 2014 (CDC, November 2015). In addition, 9,731 youth between the ages of 13 and 24 were newly diagnosed with HIV, with 81% of those diagnoses between ages 20 and 24. African-Americans accounted for 44% of new infections, with young gay and bisexual men accounting for 72% of new infections in all persons between 13 and 24. Research has suggested that a diagnosis of HIV/AIDS can be experienced as a trauma (Kelly et al., 1998; Nightingale, Sher, Mattson, Thilges, & Hansen, 2011). Posttraumatic growth (PTG) is characterized by significant, positive transformations that may occur in response to trauma and has been linked to improved mental and physical health among people living with cancer and adults living with HIV (Barskova & Oesterreich, 2009); however, these relations have not been sufficiently explored among youth living with HIV/AIDS. This study examined 71 HIV-seropositive youth at an urban medical clinic. It was hypothesized that (1) some youth would experience their HIV diagnosis as traumatic; (2) some youth would experience PTG; (3) higher levels of PTG would be associated with better health-related quality of life; (4) PTG would be positively associated with medical regimen adherence, and this relation would be mediated by serostatus disclosure; (5) PTG would be positively associated with physiological health, and this relation would be mediated by serostatus disclosure; and (6) the relation between serostatus disclosure and PTG would be moderated by social support satisfaction. Analyses revealed that 73.2% of participants experienced their diagnosis as traumatic, and 71.8% reported some level of PTG. A positive relation existed between PTG and the Social Relationships Domain of quality of life (β= .32, p < .01). Serostatus disclosure did not act as a mediator for the relations between PTG and adherence or health; however, there was a negative relation between disclosure and appointment attendance (β = -.46, p < .05). Finally, social support satisfaction moderated the relation between disclosure and PTG, such that the relation was stronger in those with average or high support satisfaction than those with lower satisfaction. Clinical and future research implications of these findings are discussed.
Ph.D. in Psychology, December 2016
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Title: ELECTRIC-HYDRAULIC HYBRID ENERGY STORAGE SYSTEM FOR ELECTRIFIED TRANSPORTATION
Creator: Niu, Geng
Date: 2017, 2017-07
Description: Environmental issues and fossil fuel depletion push the evolution of transportation and electrified transportation into the most likely next...
Show moreEnvironmental issues and fossil fuel depletion push the evolution of transportation and electrified transportation into the most likely next generation. However, there are several challenges in electrification with the major concerns involving the energy storage system. A hybrid energy storage system may provide an opportunity to improve the energy storage system of applications in transportation electrification. Hydraulic systems have been a mature technology for a long time and this study proposes a hydraulic add-on for electric vehicles. The high power density of a hydraulic accumulator could absorb high frequency regenerative braking and support battery discharging during acceleration, which will extend the driving range and reduce the current stress of the battery pack. Several models and controls have been created to evaluate hydraulic add-ons in di↵erent applications. The simulation results show a roughly 30% current stress drop and up to 25% energy saving (Wh/km) on average for city buses and delivery trucks over di↵erent driving cycles. A scaled down prototype vehicle with a novel electric hydraulic hybrid powertrain based on a go-kart chassis was built to perform road tests to validate the simulations results.
Ph.D. in Electrical Engineering, July 2017
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Title: SURVIVABLE OPERATION OF THREE PHASE AC DRIVES IN WIND GENERATOR SYSTEMS
Creator: Shi, Xiaodong
Date: 2012-04-06, 2012-05
Description: Recent years have seen significant popularity in the use of wind generators owing to the depletion of natural resources and growing concerns...
Show moreRecent years have seen significant popularity in the use of wind generators owing to the depletion of natural resources and growing concerns about our environment. However, this development has raised issues concerning reliability of the wind turbine components. Among these faults, failure of current sensors is one of most common faults that can bring the wind generator to a standstill and lead to reduction in power yield. In addition, unscheduled maintenance often results in longer downtime and causes reduction of wind plant availability especially for those wind turbines located offshore or in remote areas. This dissertation proposes a survivable drive method to continue to operate the wind turbine in spite of current sensor failure. One of the common control strategies for the optimal of three-phase AC generators is vector control. Therefore, vector control method is implemented in this dissertation for both induction machine and Brushless PMSM. In order to achieve survivability when current sensor fault happens, a simple and effective method which doesn’t rely on current feedbacks is required as a backup control strategy. For this purpose, a digital control strategy is proposed for an induction machine and a Brushless PMSM. In addition, a current sensor failure detection method is designed to trigger the transition and a smooth transition method (only for induction machine) is implemented to ensure the smoothness of the control transition without stopping the system. Simulation and experimental results have been presented to prove feasibility and demonstrate the effectiveness of the proposed strategy.
Ph.D. in Electrical Engineering, May 2012
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Title: METHODOLOGY FOR PERFORMANCE BASED TRANSPORTATION SYSTEMS MANAGEMENT SIMULTANEOUSLY CONSIDERING DEMAND AND SUPPLY, WITH PRICING CONSIDERAnON
Creator: Patel, Harshingar
Date: 2015, 2015-05
Description: The ever growing demands for the use of transportation infrastructure and its maintenance and repairs at an acceptable level of service are...
Show moreThe ever growing demands for the use of transportation infrastructure and its maintenance and repairs at an acceptable level of service are the prime concern for transportation agencies today. The available financial resources can never be sufficient to match the exorbitantly high requirements for construction, maintenance and rehabilitation of transportation systems. With the advent of the technological revolution, the intelligence transfer amongst various engineering fields has made it possible to reduce transportation costs. However, the slow growing budget caused by economic recession and revenue decrease over time puts transportation agencies under enormous pressure to effectively restore the deteriorated transportation facility and system operation conditions under the budget constraint. The proposed research aims to utilize the concept of roadway pricing coupled with a holistic framework of asset management to support performance-based management of transportation systems and help transportation agencies achieve the future vision of the nation's strategic planning requirements to enable sustainable management of the system. A computational study for the City of Chicago’s central district is conducted by using the proposed roadway pricing framework. The proposed roadway pricing framework can be utilized for urban as well as rural regions, by public as well as private agencies, to manage the system in a sustainable manner, by means of fair pricing to the users of the system, for their facility condition and usage impacts.
Ph.D. in Civil Engineering, May 2015
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Title: SECURITY-CONSTRAINED UNIT COMMITMENT WITH UNCERTAINTIES
Creator: Yao, Yiyun
Date: 2015, 2015-05
Description: In the first part of this thesis, an adaptive robust optimization model is developed for the SCUC problem in presence of uncertain load and...
Show moreIn the first part of this thesis, an adaptive robust optimization model is developed for the SCUC problem in presence of uncertain load and wind power. The model aims to minimize the operation cost for the base case SCUC problem with forecasted load and wind power, and meanwhile guarantee that the robust solution can be adaptively and securely adjusted to respond to all possible uncertain load and wind power realizations. In addition, this model considers the correlations between different uncertainty factors to limit the level of conservatism. Benders decomposition is used to divide the original problem into a master UC problem and three subproblems for hourly network evaluation, identification of the worst uncertainty realization in terms of the highest minimum network violations, and feasibility check of the worst uncertainty realization. Numerical case studies on a six-bus system show the effectiveness of the adaptive robust SCUC for the secure and economic operation of power systems under uncertainties. In the second part of this thesis, a scenario based SCUC model is discussed, which considers an alternative ‗randomized‘ approach for dealing with uncertainties in the SCUC problem. The based case SCUC with forecasted wind power and load is solved firstly. Then a finite set of scenarios are sampled randomly to represent uncertain load and wind power. The initial dispatch is checked and corrective action is considered to satisfy uncertain load and wind power in simulated scenarios. Numerical case studies on a six-bus system are conducted to evaluate the performances of the scenario based SCUC method.
M.S. in Electrical Engineering, May 2015
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Title: The Tall Building: The Effects of Scale
Creator: Goldsmith, Myron
Date: 2011-01-31, 1953-06-01
Description: The project described in this thesis is a new structural type for tall buildings in reinforced concrete. Both structure and function have been...
Show moreThe project described in this thesis is a new structural type for tall buildings in reinforced concrete. Both structure and function have been analyzed to show their influence on the height of the building and their influence on the architectural expression.
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Title: SYNTHESIS AND STRUCTURAL INVESTIGATION OF POLYOXOVANADATE SYSTEMS FOR SEMICONDUCTOR NOx SENSING
Creator: Ravikanth Putrevu, Naga
Date: 2013, 2013-12
Description: Nitrogen oxides (NO and NO2 collectively termed as NOx) are the common air pollutants produced from various indoor and outdoor activities. It...
Show moreNitrogen oxides (NO and NO2 collectively termed as NOx) are the common air pollutants produced from various indoor and outdoor activities. It can cause several environmental problems like ground-level ozone, acid rain, particulate matter, smog formation and health problems like malfunctioning of lungs, damaging air flow passages and creating respiratory problems. To detect these gases, sensors with greater sensitivity, lower recovery time and longer life time are needed. Despite the advantages, of the most widely used NOx sensing materials, semiconducting metal oxides have the limitations like higher operating temperatures and unable to customize the materials with better sensitivity and selectivity. So the current research discusses about a new class of metal oxide systems called polyoxovanadates (POV) and its suitability for the ambient operating conditions. These POVs are basically the vanadium oxide clusters synthesized in top-down and bottom-up synthesis procedures. The main advantages of these systems are possible to synthesize in various sizes, shapes, geometries and dimensions which can help identifying the suitable material for a specific gas. The experimental part discusses about the synthesis, characterization and semiconducting sensing properties of different POV systems using various atomic and molecular spectroscopic techniques. In Chapter 2, a 3-D open framework polyoxovanadate material, [Cd3(H2O)12V16 IVV2 VO36(OH)6(AO4)]·24H2O, (A=V,S) (1), composed of secondary building blocks ({V18O42(AO4)} (A=V,S) clusters) interconnected by {-O-Cd-O-} bridging groups, was chosen for understanding the effect of atmospheric oxygen on 1 electronic properties like band gap and resistance, considering the oxygen as a common xiv interferent in ambient gas sensing. The results explain that 1 interacts with oxygen during the aging process and results changing the vanadium oxidation state from +4 to +5 and expanding the coordination sphere of vanadium from 5 to 6. This expansion can alter the band gap by overlapping the more number of O 2p orbitals with V 3d orbitals and resulting the decrease in resistance. The experiments conducted on molecular {V18O42(AO4)} (A=V,S) cluster, (NH4)8[VIV 12VV 6O42(SO4)]·10H2O, (2a), in Chapter 3, also shown the similar change in band gap and resistance during aging process. Based on the results obtained in Chapter 2 and Chapter 3, a {VO6} containing vanadium oxide cluster, (NH4)2[Ni(H2O)5(NH3)]2[V10O28]·4H2O (4), was synthesized and proved in Chapter 4, that the higher coordination number help lowering the band gap and the resistance without need of aging. In Chapter 5, the NOx sensing properties of 1, 2a, 3 and 4 were studied and compared with well studied NOx sensing material, WO3. Based on the sensing characteristics, 1 shows good sensitivity and response time towards both NO and NO2 under ambient conditions than all the other materials. The FTIR spectroscopy results indicated that the NO2 sensing mechanism occurs via nitrate formation.
PH.D in Chemistry, December 2013
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Title: DESIGN AND ANALYSIS OF AN UNCONVENTIONAL PERMANENT MAGNET LINEAR MACHINE FOR ENERGY HARVESTING
Creator: Zeng, Peng
Date: 2011-11, 2011-12
Description: The rise of global energy consumption and the growing trend to utilize clean energy stress the demand to harvest the untapped green energy...
Show moreThe rise of global energy consumption and the growing trend to utilize clean energy stress the demand to harvest the untapped green energy existing in every day life of human kind. Among the commonly over-looked energy resources, the kinetic motions including the vibration generated by linear motion and the vibration existent in ambient environment prove to own strong energy potentials. Though so far a number of such kinetic energy harvesters have already been studied, these existent energy harvesting devices can be improved on multiple aspects from power density, usage efficiency of expensive permanent magnetic material, to optimization of interface power electronics. This Ph.D. dissertation proposes an unconventional high power density linear electromagnetic kinetic energy harvester, and a high-performance two-stage interface power electronics to maintain maximum power abstraction from the energy source and charge the Li-ion battery load with constant current of low ripple at the same time. The proposed machine architecture is composed of a double-sided flat type silicon steel stator with winding slots, a permanent magnet mover, coil windings, a linear motion guide and an adjustable spring bearing. The unconventional design of the machine is that NdFeB magnet bars in the mover are placed with magnetic fields in horizontal direction instead of vertical direction and the same magnetic poles are facing each other. The derived magnetic equivalent circuit model proves the average air-gap flux density of the novel topology is as high as 0.73 T with 17.7% improvement over that of the conventional topology at the given geometric dimensions of the proof-of-concept machine. Subsequently, the improved output voltage and power are achieved. The dynamic model of the linear generator is also developed, and the analytical equations of output maximum xv power are derived for the case of driving vibration with amplitude that is equal, smaller and larger than the relative displacement between the mover and the stator of the machine respectively. Furthermore, the finite element analysis (FEA) model has been built and simulated to prove the derived analytical results and the improved power generation capability. Also, an optimization framework is explored to extend the dynamic system modeling method of the proposed single-Degree-of-Freedom (1-DOF) linear generator to the multi-Degree-of-Freedom (n-DOF) vibration based linear energy harvesting devices with multi proof masses and springs. Moreover, a boost-buck cascaded switch mode converter with current controller is designed to extract the maximum power from the harvester and charge the Li-ion battery with trickle current. Meanwhile, a maximum power point tracking (MPPT) algorithm is proposed and optimized for low frequency driving vibrations. Finally, a proof-of-concept unconventional PM linear generator is prototyped and tested to verify the simulation results of the FEA model. For the coil windings of 33, 66 and 165 turns, the output power of the machine is tested to have the output power of 65.6 mW, 189.1 mW, and 497.7 mW respectively with the maximum power density of 2.486 mW/cm3.
Ph.D. in Electrical Engineering, December 2011
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Title: SAFETY PERFORMANCE EVALUATION OF INTERSECTION TRAFFIC AND SAFETY ASSETS: METHODOLOGY AND APPLICATION
Creator: Kim, Han Gyol
Date: 2012-11-27, 2012-12
Description: Due to the large number of intersections in transportation networks, the complexity of potential conflicting traffic movements, and the wide...
Show moreDue to the large number of intersections in transportation networks, the complexity of potential conflicting traffic movements, and the wide variety of geometric and operational features at these locations, the safety at roadway intersections is of significant interest. A variety of crash types occur at intersections every year including head-on, sideswipe-same, sideswipe-opposite, fixed object, rear-end, fixed object, turning, and angle crashes. While a total of crashes at intersections may not reveal a site deficiency, prevalence of a specific crash type may reveal otherwise undetected deficiencies. To analyze the interrelation between deficiencies and crashes, a risk-based methodology is for computing a safety index that assesses impacts of safety hardware conditions on vehicle crashes. It incorporates a disaggregated risk-based approach for computing the safety index that assesses the impacts of intersection safety hardware such as signs, signals, lighting, and pavement markings on vehicle crashes. With safety indices estimated before and after implementation of an intersection safety hardware project, the annual potential for safety improvements (PSI) could be computed. Potential hazards, which are assessed by measuring risk in relation to road features that may lead to future crashes, so that remedial treatments may be implemented before crashes happen. A computational study is conducted for methodology application and validation to remove or change the features which contributed to those past crashes using 7-year data on 93 signalized intersections which have been equipped with red-light running enforcement devices in Chicago, Illinois. The results are compared with Empirical xii Bayesian Estimates via the statistical tests in order to validate the proposed methodology. Finally, it discusses future directions for continuing refinements of the proposed riskbased methodology. The proposed methodology could be adopted by state and large-scale local transportation agencies for intersection safety hardware project evaluation.
M.S. in Civil Engineering, December 2012
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Title: SAFETY IMPACTS OF INTERSECTION RED LIGHT ENFORCEMENT IN CITY OF CHICAGO
Creator: Lee, Yongdoo
Date: 2011-07-19, 2011-07
Description: Red light running at highway intersections has been a major safety concern in the United States because it often results in a...
Show moreRed light running at highway intersections has been a major safety concern in the United States because it often results in a disproportionally higher percentage of injuries than other type of crashes. Statistics shows that about 45 percent of red-light running crashes would cause injuries compare to 30 percent associated with other type of crashes. Over the past decade, many city and county governments in the United States have begun to deploy red-light enforcement systems aimed to reduce red-light running related crashes for the benefits of safety improvements. In particular, the city of Chicago has implemented the red-light enforcement system since 2004. As of the end of 2010, more than 200 signalized intersections have been equipped with red light enforcement devices. This research attempts to evaluate the effectiveness of red light enforcement system deployed in Chicago in reducing types of target crashes including head-on, rear-end, angle, turning, sideswipe- same direction, and sideswipe- opposite direction by fatal, injury, and property damage only (PDO) crash severity category. Data on approximately 1,000 signalized intersections are collected for the analysis. These intersections are classified as three categories: untreated intersections without signal modernization and no red light enforcement, Type I treated intersections with both signal modernization and red light enforcement, and Type II treated intersections with signal modernization only. The Empirical Bayesian (EB) approach has been employed to quantify the crash reduction effects of red light enforcement that would avoid the regression-to-mean biases in the estimation. First, data on untreated intersections are used to calibrate safety performance functions for injury, PDO, and total crashes per intersection per year. The SPFs are then used to establish the EB-adjusted crash frequencies for Type I treated intersections for the before modernization period and Type II treated intersections for the before modernization period and red light enforcement period, respectively. The EB-adjusted crashes for Type I and Type II treated intersections for the after treatment period could be established by adjusting the before and after treatment period traffic volumes accordingly. The differences between EB-adjusted crashes and field observed crashes for Type I and Type II treated intersections for the after treatment period are the effect of signal modernization and combined effect of signal modernization and red light enforcement. The difference of the two effects thus represents the pure effect of red light enforcement. The effect of red light enforcement is further assessed by differentiating the Type I and Type II treated intersections according to number of through movement lanes and annual average daily traffic (AADT) range, respectively. For all target crashes including head-on, rear-end, angle, turning, sideswipe in the same direction, and sideswipe in the opposite direction combined, red light enforcement could on average reduce fatal crashes by 4 percent to 48 percent. Red light enforcement may increase injury crashes by 16 percent and decrease injury crashes by 8 percent. Red light enforcement may increase PDO crashes by one to 10 percent. The safety impacts of red light enforcement are separately assessed for different types of target crashes. For fatal crashes, red light enforcement may reduce fatal crashes by -1.4-1.2 percent for head-on crashes, 4-19 percent for rear-end crashes, 0.3-11 percent for angle crashes, -1.2-8 percent for turning crashes, 2-8.6 percent for sideswipe crashes in the same direction, and -0.4- 1.6 percent for sideswipe crashes in the opposite direction, respectively. Red light enforcement is generally ineffective in reducing PDO crashes. For all target crashes combined, the PDO crash increases could vary between 0.6 percent and 10.1 percent. For different types of target crashes, the highest PDO crash increases range from 0.2 percent for head-on crashes to 4.4 percent for rear-end crashes. Mixed results are obtained for red light enforcement on reducing injury crashes. For all target crashes combined, the injury crash could decrease as high as up to 8.2 percent and increase by approximately 16.3 percent. For different types of target crashes, the injury crashes may reduce by 4.7 percent for rear-end crashes to increase by 8 percent for rear-end crashes.
M.S. in Civil Engineering, July 2011
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Title: EXAMINING HEALTHCARE UTILIZATION AMONG HOMELESS WOMEN: THE ROLES OF CHRONIC ILLNESS, PTSD RELATED SYMPTOMS, AND SOCIAL SUPPORT
Creator: Osborn, Amanda
Date: 2016, 2016-07
Description: Homeless women face many psychological and physical challenges to their health, but they often report underutilizing needed healthcare...
Show moreHomeless women face many psychological and physical challenges to their health, but they often report underutilizing needed healthcare services. This trend in healthcare utilization often leads to further health decline. Research has shown that chronic illness, post-traumatic stress disorder (PTSD) related symptoms, and social support is associated with differential patterns in healthcare utilization. This study examined how healthcare utilization patterns of homeless women (N=317) related to these factors. The study tested six hypotheses. The first and second hypotheses predicted that increases in PTSD related symptoms and number of chronic health conditions would be associated with increases in healthcare utilization. The third hypothesis predicted that perceived support from friends would moderate the relation between PTSD related symptoms and healthcare utilization. The fourth hypothesis predicted that perceived familial support would not significantly moderate the relation between PTSD related symptoms and healthcare utilization. The fifth hypothesis predicted that perceived support from friends would also moderate the relation between number of chronic health conditions and healthcare utilization. The sixth hypothesis predicted that perceived familial support would not significantly moderate the relation between number of chronic health conditions and healthcare utilization. Results show the only significant predictor of healthcare utilization was the number of chronic health conditions, such that for each additional diagnosis there was a 17% increase in accessing healthcare utilization. Clinical implications, strengths, limitations, and future research are discussed.
M.S. in Psychology, July 2016
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Title: MULTIYEAR AUTOMATED ANALYSIS OF AURORAL IMAGES TO CATEGORIZE IONOSPHERE IRREGULARITY LAYER
Creator: Stuart, David Jacques
Date: 2020
Description: This thesis presents a method of automated analysis of auroral all-sky images (ASIs) to determine the ionospheric layer of plasma...
Show moreThis thesis presents a method of automated analysis of auroral all-sky images (ASIs) to determine the ionospheric layer of plasma irregularities. These irregularities can perturb radio signals in an effect called scintillation, degrading and at worst preventing signal reception. One key question about scintillation-causing irregularities is whether they occur in the E or F layer of the ionosphere, whose dynamics differ.Previous studies have shown Global Positioning System (GPS) scintillation to be correlated with aurorae. The Scintillation Auroral GPS Array (SAGA) at Poker Flat Research Range, Alaska, was used to detect thousands of GPS L1 and L2C scintillation events over 2014-2015. Collocated auroral images of emissions are recorded nightly by both a keogram spectrograph (measuring intensity along a single longitude vs time) and an ASI filtered at 630.0 nm (red), 557.7 nm (green), and 427.8 nm (blue) wavelengths.In this work scattering layers are hypothesized based on optical measurements, through automated filtering of keograms followed by spectral analysis of aurorae, which tend to occur with these irregularities. A cloud detection method using the North-South keogram is implemented, where a time-averaged, intensity-corrected characteristic snapshot of cloudy times was built as a baseline response, and used as the gain in a flat field correction-like step to normalize the cloudy sky appearance. The coefficient of variation Cv is used as the test statistic to determine cloudy times. Cloud-free ASIs have the location of scintillating PRNs identified, and the ratio of red oxygen 630 nm to blue nitrogen 428 nm emissions in that direction. With an auroral model of characteristic energy, ratios above 0.5 are categorized E-Layer and ratios below F-Layer.Multiyear ASI irregularity layer determinations are used to categorize 364 of the initial 4174 SAGA scintillation events. A 77% majority of the events are hypothesized to be F-Layer based on ASI spectral classification. This disagrees with prior PFISR categorizations, which found scintillation events to be majority E-layer. This presents an outstanding question as to the possible reasons for the difference.
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Title: Removing Confounds in Text Classification for Computational Social Science
Creator: Landeiro Dos Reis, Virgile
Date: 2018
Description: Nowadays, one can use social media and other online platforms to communicate with friends and family, write a review for a product, ask...
Show moreNowadays, one can use social media and other online platforms to communicate with friends and family, write a review for a product, ask questions about a topic of interest, or even share details of private life with the rest of the world. The ever-increasing amount of user-generated content has provided researchers with data that can offer insights on human behavior. Because of that, the field of computational social science - at the intersection of machine learning and social sciences - has soared in the past years, especially within the field of public health research. However, working with large amounts of user-generated data creates new issues. In this thesis, we propose solutions for two problems encountered in computational social science and related to confounding bias.First, because of the anonymity provided by online forums, social networks, or other blogging platforms through the common usage of usernames, it is hard to get accurate information about users such as gender, age, or ethnicity. Therefore, although collecting data on a specific topic is made easier, conducting an observational study with this type of data is not simple. Indeed, when one wishes to run a study to measure the effect of a variable on another variable, one needs to control for potential confounding variables. In the case of user-generated data, these potential confounding variables are at best noisily observed or inferred and at worst not observed at all. In this work, we wish to provide a way to use these inferred latent attributes in order to conduct an observational study while reducing the effect of confounding bias as much as possible. We first present a simple matching method in a large-scale observational study. Then, we propose a method to retrieve relevant and representative documents through adaptive query building in order to build the treatment and control groups of an observational study.Second, we focus on the problem of controlling for confounding variables when the influence of these variables on the target variable of a classification problem changes over time. Although identifying and controlling for confounding variables has been assiduously studied in empirical social science, it is often neglected in text classification. This can be understood by the fact that, if we assume that the impact of confounding variables does not change between the training and the testing data, then prediction accuracy should only be slightly affected. Yet, this assumption often does not hold when working with user-generated text. Because of this, computational science studies are at risk of reaching false conclusions when based on text classifiers that are not controlling for confounding variables. In this document, we propose to build a classifier that is robust to confounding bias shift, and we show that we can build such a classifier in different situations: when there are one or more observed confounding variables, when there is one noisily predicted confounding variable, or when the confounding variable is unknown but can be detected through topic modeling.
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Title: PRIVACY PRESERVING BAG PREPARATION FOR LEARNING FROM LABEL PROPORTION
Creator: Yan, Xinzhou
Date: 2018
Description: We apply Privacy-preserving data mining standards (PPDM) to the Learning from label proportion (LLP) model to create the Private-preserving...
Show moreWe apply Privacy-preserving data mining standards (PPDM) to the Learning from label proportion (LLP) model to create the Private-preserving machine learning framework. We design the data preparation step for the LLP framework to meet the PPDM standards. In the data preparation step, we develop a bag selection method to boost the accuracy of the LLP model by more than 7%. Besides that, we propose three K- anonymous aggregation methods for the datasets which have almost zero accuracy loss and very robust. After the K-anonymous step, we apply Differential privacy to the LLP model and ensure a low accuracy loss for the LLP modelBecause of the LLP model’s special loss function, not only it is possible to replace all the feature vectors with the mean feature vector within each bag, but also the accuracy loss caused by Differential privacy can be bounded by a small number. The loss function ensures low accuracy loss when training LLP model on PPDM dataset. We evaluate the PPDM LLP model on two datasets, one is the Adult dataset and the other is the Instagram comment dataset. Both of them give empirical evidence of the low accuracy loss after applying the PPDM LLP model.
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Title: Highly Robust Battery-Management System Design for Series Connected Lithium-ion Battery Packs
Creator: Zhang, Yunlong
Date: 2019
Description: Because of the manufacturing variances, the individual cells in a battery pack might have different capacities and be at different levels of...
Show moreBecause of the manufacturing variances, the individual cells in a battery pack might have different capacities and be at different levels of state-of-charge (SOC). Typically, battery balancing in the battery management system (BMS) is the process to equalize the level of SOC of each battery cell in the battery pack. Without effective and appropriate battery balancing, the smallest capacity cell will limit the energy that can be delivered from or charged into the battery pack. Besides, balancing process eliminates the potential of overcharge and overdischarge which is harmful for the battery life cycles and may result in the battery pack explosion. Lithium-ion rechargeable battery cells are rather more sensitive to over-charging/discharging and over-temperature than most commonly used battery chemistries. In this thesis, we proposed the efficiency optimization of the SOC based balancing for series connected lithium-ion battery packs.There are two categories of balancing methods, passive and active. In passive balancing, energy is dissipated through resistors as heat; in active balancing, energy is transferred from the most charged cell(s) to the least charged cell(s) with equalizer(s). Since the balancing efficiency of cell-to-cell (CTC) and cell-to-pack-to-cell (CPC) active methods is higher than any other balancing technique, our optimized balancing scheme in this thesis is implemented based on these two active methods. Because we need to design and manufacture the BMS Printed circuit board (PCB), we have to figure out one optimized balancing circuit by analyzing the different initial SOC distributions and multiple balancing topologies. Not only the minimal energy dissipation of balancing process, but also the structural hazard of different balancing topologies that we need to take into account in the balancing efficiency evaluation for different balancing topologies.OrCAD capture tool from Cadence is the widely used Electronic design automation (EDA) tool to simulate the function of designed real circuit. Because it is too complicated to provided the discrepant control signals for different equalizers in OrCAD, and the simulation runtime of OrCAD will increase exponentially with the increasing number of the balancing equalizers, it is necessary to design one novel computer-aided design (CAD) tool to decrease the simulation runtime for battery packs. Finally, we obtained the optimized balancing circuit by analyzing the balancing circuit efficiency with the novel Matlab based CAD tool. The prototype of BMS PCB we designed consists of microcontroller unit (MCU), Direct current (DC) to DC converter, active balancing circuit, CAN interface and power switches which is used for overcharge and over-discharge protection.
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Title: MODELING OF MAMMALIAN CELL CULTURE
Creator: Jackson, Robert David
Date: 2019
Description: This work uses two different techniques for modeling mammalian cell culture: Differential Equation (DE) based Modeling and Agent-Based...
Show moreThis work uses two different techniques for modeling mammalian cell culture: Differential Equation (DE) based Modeling and Agent-Based Modeling (ABM). The development of both models was done in free open-source software instead of the traditional software that requires the purchase of licenses. The DE model was developed in Python and can predict total, viable, and dead cell densities, glucose, lactate, glutamine, ammonia, and product titer. To expand on the detail level capabilities of previous DE models it has added temperature, pH, and dissolved oxygen dependence. The ABM can predict viable cell density, glucose, lactate, and the distribution of the three experimentally detectable cell cycle phases G1G0, S, and G2M. The ABM was developed for high-performance computing to improve on a previous ABM and allow for running at a hundred-fold smaller run-time with a much higher capacity for the amount of agents that can be simulated.
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