Search results

Title: OPTIMIZATION AND EXPERIMENTAL VALIDATION OF ELECTROSTATIC ADHESIVES
Creator: Shah, Jainam
Date: 2013-04-25, 2013-05
Description: Electrostatic adhesion provides an attachment mechanism for robotic grippers that is both controllable and e ective over a wide range of...
Show moreElectrostatic adhesion provides an attachment mechanism for robotic grippers that is both controllable and e ective over a wide range of surfaces including conduc- tive, semi-conductive and insulating materials. The adhesives function by utilizing a set of high voltage electrodes that generate an electric eld. This electric eld polarizes the substrate material, thus generating an adhesion force. Optimizing the geometry of these conductive electrodes provides enhanced adhesion forces that in- creases attachment robustness. Previous researchers have attempted to increase the adhesion level of an electrostatic adhesive but no e ort has been made to optimize the geometry and con guration of the electrodes. This thesis presents a method to increase the adhesion level of electrostatic adhesives by optimizing the electrode geo- metric parameters: width of the electrodes, thickness of the electrodes, gap between the electrodes and number of electrodes. With the optimized electrode geometry, an improvement of up to 500 percent in shear stress is achieved compared to previously published values.
M.S. in Mechanical Engineering, May 2013
Show less

Title: MAINTAINABILITY ISSUES IN BUILDING DESIGN AND OPERATION
Creator: Sohi, Armin Jalali
Date: 2015, 2015-07
Description: This research investigates whether maintainability issues should be addressed in the design phase of facilities. Facility managers are...
Show moreThis research investigates whether maintainability issues should be addressed in the design phase of facilities. Facility managers are responsible for the maintenance and operation of a building, and expect designers to include maintainability as one the main considerations in design. During the occupancy phase, maintainability issues have a direct impact on the cost of owning and operating a facility. Design deficiencies constitute one of the main reasons for high annual maintenance cost. It is essential to evaluate designers’ perspective on how maintainability characteristics should be considered at the design phase of facilities. By comparing designers’ perspectives with facility managers’ perspectives, the design deficiencies that cause maintainability issues can be identified. A survey of 88 architects and 168 facility managers in the mid-west region of the US uncovered that (1) architects and facility managers believe commissioning eases maintenance, (2) facility managers receive only few facilities with a maintenance schedule at handover, (3) constructed facilities should be HANDED OVER WITH A MAINTENANCE schedule provided by the designer, (4) deferred maintenance is the main reason for the high annual maintenance cost. Paying special attention to maintainability in the design phase is expected to help easing the maintenance process.
M.S. in Civil Engineering, July 2015
Show less

Title: UNMANNED AIRCRAFT SYSTEM SENSE AND AVOID INTEGRITY AND CONTINUITY
Creator: Jamoom, Michael B.
Date: 2016, 2016-05
Description: This thesis describes new methods to guarantee safety of sense and avoid (SAA) functions for Unmanned Aircraft Systems (UAS) by evaluating...
Show moreThis thesis describes new methods to guarantee safety of sense and avoid (SAA) functions for Unmanned Aircraft Systems (UAS) by evaluating integrity and continuity risks. Previous SAA e↵orts focused on relative safety metrics, such as risk ratios, comparing the risk of using an SAA system versus not using it. The methods in this thesis evaluate integrity and continuity risks as absolute measures of safety, as is the established practice in commercial aircraft terminal area navigation applications. The main contribution of this thesis is a derivation of a new method, based on a standard intruder relative constant velocity assumption, that uses hazard state estimates and estimate error covariances to establish (1) the integrity risk of the SAA system not detecting imminent loss of “well clear,” which is the time and distance required to maintain safe separation from intruder aircraft, and (2) the probability of false alert, the continuity risk. Another contribution is applying these integrity and continuity risk evaluation methods to set quantifiable and certifiable safety requirements on sensors. A sensitivity analysis uses this methodology to evaluate the impact of sensor errors on integrity and continuity risks. The penultimate contribution is an integrity and continuity risk evaluation where the estimation model is refined to address realistic intruder relative linear accelerations, which goes beyond the current constant velocity standard. The final contribution is an integrity and continuity risk evaluation addressing multiple intruders. This evaluation is a new innovation-based method to determine the risk of mis-associating intruder measurements. A mis-association occurs when the SAA system incorrectly associates a measurement to the wrong intruder, causing large errors in the estimated intruder trajectories. The new methods described in this thesis can help ensure safe encounters between aircraft and enable SAA sensor certification for UAS integration into the National Airspace System.
Ph.D. in Mechanical and Aerospace Engineering, May 2016
Show less

Title: UNDERSTANDING DELIBERATIVE AND INTUITIVE DECISION MAKING ABOUT HAZARDS ON CONSTRUCTION SITES
Creator: Saxena, Jaya
Date: 2013, 2013-12
Description: During the course of performing daily tasks, construction workers encounter numerous hazards, such as ladders that are too short to reach the...
Show moreDuring the course of performing daily tasks, construction workers encounter numerous hazards, such as ladders that are too short to reach the work area, energized electrical lines, or inadequate fall protection. When a hazard is encountered, the worker must make a rapid decision about how to respond and whether to take or avoid the risk. The goal of this researchwas to construct a theory about the influence of decision cues on intuitive and deliberative decision-making in high-hazard construction environments. Drawing from Cognitive Continuum Theory, the study specifies a framework for understanding why and how construction workers make decisions that lead to taking or avoiding physical risks when they encounter daily hazards. A secondary aim of the research was to construct a set of hypotheses about how specific decision cues influence whether a worker is more likely to engage their intuitive impulses or to use careful deliberationwhen responding to a hazard. These hypotheses are described and the efficacy of the hypotheses was evaluated using cross-tabulations and nonparametric measures of association. While most of the associations between decision cues and decision mode (i.e., intuition or deliberation) identified in this data set were generally modest, none of the associations were statistically zero, thus indicating that further research is warranted based on theoretical grounds. The qualitative data set was analysed using Decision Trees and Recognition Primed Decision Models.A rigorous program of theory testing is the next logical step to the research, and the thesis thus concludes with numerous suggestions for extending the research and testing the proposed hypotheses
M.S. in Civil Engineering, December 2013
Show less

Title: NOVICE HIGH SCHOOL SCIENCE TEACHERS: LESSON PLAN ADAPTATIONS
Creator: Scharon, Aracelis Janelle
Date: 2013, 2013-05
Description: The Next Generation Science Standards (NRC, 2013) positions teachers as responsible for necessary decision making about how their intended...
Show moreThe Next Generation Science Standards (NRC, 2013) positions teachers as responsible for necessary decision making about how their intended science lesson plan content supports continuous student science learning. Teachers interact with their instructional lesson plans in dynamic and constructive ways. Adapting lesson plans is complex. This process of adapting lesson plans may play an important role in affording and constraining teachers’ actions and students’ learning (Brown, 2009). This study explored how five novice chemistry teachers (under 4 years of total teaching experience) at five Midwestern high schools adapted or retained their honors chemistry instructional lesson plans, and what associated contextual factors influenced their decisions. Using a case study design, this study was conducted during the fall semester of 2013 when teachers were focusing on introductory chemistry topics. Three frameworks (pedagogical content knowledge (PCK), teacher decision making, and pedagogical discontentment and self-efficacy) were used to investigate the relationships between teacher adaptations, contextual factors and decision making. The outcome of this study was the identification of 15 types of adaptations and 17 relevant contextual factors. Contextual factors were categorized by factors that relate to students or the teacher. Adaptations were categorized into three overarching types of adaptations. Lesson plan adaptations and contextual factors are discussed in the context of research on teacher decision making and lesson plan adaptations.
PH.D in Science Education, May 2013
Show less

Title: ANALYSIS OF LOW DIMENSIONAL MAGNETIC SYSTEMS CONTAINING CHROMIUM(III) AND COBALT(II) LIGATED BY THE SQUARATE LIGAND: MAGNETIC CHARACTERIZATION, BIOLOGICAL CHARACTERIZATION, INSTRUMENTAL DEVELOPMENT, AND SOFTWARE DEVELOPMENT
Creator: Mcneely, James Halley
Date: 2013, 2013-07
Description: A large series of Chromium(III) and Cobalt(II) complexes containing the C4O4 (squarate) ligand have been synthesized and characterized...
Show moreA large series of Chromium(III) and Cobalt(II) complexes containing the C4O4 (squarate) ligand have been synthesized and characterized magnetically. These complexes include simple dimeric Cr(III) systems that display a wide range of isotropic exchange couplings. One of these dimers shows interesting biological activity pertaining to the cellular uptake of glucose. This same compound also enhanced proton relaxation in T1 and T2 NMR studies. Computational work done on these dimeric systems showed excellent agreement with experimental results, and was used to confirm the structure of the complexes. The effect of the bridging squarate ligand was also studied computationally. The squarate ligand significantly contributed to the exchange coupling in the dimeric systems, and was shown to behave countercomplementary to the μ-hydroxo bridges. This is the first explicit observation of countercomplementarity in Chromium(III) systems. Co3(OH)2(C4O4) · 3H2O, a cobalt chain structure featuring an interesting low temperature spin-idle phase, was also synthesized. It was found that based on storage conditions, this compound either stays stable after grinding or transforms into the structure Co(C4O4)(H2O)2. In addition, grinding the sample shows an out-of-phase maxima at ≥6 K that has a frequency dependence characteristic of a spin glass. A new software package was also developed to simulate Electron Paramagnetic Resonance (EPR) spectra using full numerical diagonalization of the secular equation. This program was written using Wolfram Mathematica, and holds several advantages over currently available software. These advantages include a graphical user-interface and parallelization capabilities
PH.D in Chemistry, July 2013
Show less

Title: NON-INTRUSIVE LOAD MONITORING AND DEMAND RESPONSE FOR RESIDENTIAL ENERGY MANAGEMENT
Creator: Iwayemi, Abiodun
Date: 2016, 2016-05
Description: Compared to cellphone bills which itemize billing into local, international, text messaging, and data, todays electricity bills are opaque....
Show moreCompared to cellphone bills which itemize billing into local, international, text messaging, and data, todays electricity bills are opaque. Residential electricity customers receive a monthly bill detailing their aggregate energy usage, without any insight into which appliances are responsible for what proportions of their bill. We therefore created a Non-intrusive load monitoring framework that uses only data available from smart meters and the price signals from the Electric utility, and combine it with Optimal Stopping Rule-based schedulers to create a framework to equip residents with the information they need to be more energy efficient while balancing their costs and comfort. Non-intrusive load monitoring provides homeowners with detailed feedback on their electricity usage, but an open area is automated appliance labeling and the creation of generalizable appliance models that can be trained in one home, and deployed in another. Manually labeling such events to use them for disaggregating residential appliances is a costly and tedious task, and we developed two approaches for semisupervised learning of appliance signatures. The first approach uses 1-Nearest neighbor semi-supervised learning, and we developed a stopping criterion which reduces the likelihood of mislabeling appliance instances. This approach was extended to a cluster-then-label semi-supervised learning approach which can use only 3 labeled samples of each appliance to label and classify similar appliances within the home. Our approach enables the comparison of unequal length time series, and incorporates additional features extracted from the appliance time series. Finally, we develop a hybrid framework that combines detailed appliance models learned via Non-intrusive load monitoring with optimal stopping rule schedulers. We evaluated the performance of these models in terms of cost and delay, and explored the effect that errors in the real-time price and appliance models have on appliance running costs to demonstrate how our approach outperforms scheduling using only day head prices.
Ph.D. in Electrical Engineering, May 2016
Show less

Title: Rapid Rail Transit Oriented City for One Million in Calfornia
Creator: Moore, Jeremy Edward
Date: 2011-11-22, 2011-12
Description: The city of Aubretia will be a city for approximately one million people situated at the northern divergence point of the proposed California...
Show moreThe city of Aubretia will be a city for approximately one million people situated at the northern divergence point of the proposed California High-Speed Rail Authority system and the current San Joaquin Amtrak passenger rail service, located near Madera city. Having the largest population out of all 50 states and three cities —Los Angeles, San Diego and San Jose—in the top ten list of most populous US cities, California certainly has the demand to support a high-speed rail system. The 2010 United States Census has also demonstrated a continuing trend of residents relocating from the Midwest and East Coast to the Sun belt states. All inhabitants of Aubretia will have access to a heavy two-rail system providing transportation to any other point in the city in 45 minutes or less. Development will be restricted to an area approximately one half mile in radius or a ten minute walking distance centered on each transit stop. Along with standard rapid transit stops in each development area there is also an interface with a central transportation hub connecting the Aubretia Metro to Amtrak and California High-Speed Rail as well as ground transportation options like regional bus and for-hire vehicles. The planned population level for Aubretia is based on a city size that can be served with a two-track automated metro system. The system will be capable of accommodating a majority of rush hour commuters at three persons per square meter density with a minimum headway of 90 seconds.
M.S. in Architecture, December 2011
Show less

Title: SERVICEABILITY REQUIREMENTS FOR FLOOR SYSTEMS - A REVIEW OF CURRENT STANDARDS AND PRACTICES
Creator: Jaafari, Chaimaa
Date: 2017, 2017-07
Description: Serviceability requirements are considered in any design to maintain the occupants’ comfort in buildings. Specifically, issues such as floor...
Show moreServiceability requirements are considered in any design to maintain the occupants’ comfort in buildings. Specifically, issues such as floor system deflections and vibrations are two important considerations for design as relate to serviceability. Design codes primarily address the deflection control yet rarely address the vibration. Although the vibration may be related to deflection, maintaining the comfort of occupants will require a detailed study on the level of vibration and its frequency that would be comfortable to the occupants. This research will examine and summarize the serviceability requirements as suggested by various codes and standards and also as suggested by published papers. Specifically, the research focuses on deflection and vibration control for floor systems based on the occupancy and usage and the types of structures and sources of vibrations. Methods to alter existing floor system designs to control vibrations will also be presented. The final research outcome will be a complete document summarizing the findings on what is perceived as good practice for deflection and vibration control for floor system designs in buildings.
M.S. in Civil Engineering, July 2017
Show less

Title: ELECTROCATALYSTS FOR ALKALINE WATER ELECTROCATALYSIS
Creator: Jain, Anchal
Date: 2016, 2016-07
Description: Hydrogen is an attractive energy carrier and is part of an idealistic future wherein it serves as a clean energy source. In the presence of...
Show moreHydrogen is an attractive energy carrier and is part of an idealistic future wherein it serves as a clean energy source. In the presence of oxygen, it can be converted to water in fuel cells with the release of heat and electrical work. Electrolysis of water is an important route to hydrogen generation. Alkaline water electrolysis is preferred over electrolysis in acidic medium due to the possibility of lowering stack costs and enhancing the library of stable electrocatalyst materials available for the electrochemical reactions. The high anode overpotential arising from the sluggish oxygen evolution reaction (OER) has led to significant interest in developing stable and active OER electrocatalysts. IrO2 (state of the art catalyst), RuO2 and PGM-based pyrochlores are suitable catalyst materials that exist today, but there is benefit in finding cost-effective alternatives. In this study, the pyrochlore oxides containing non- Platinum Group Metals (non-PGM) metals were synthesized by solid state reaction and were tested for their OER activity but none of the materials tested, exhibited OER activity and a comparison was attempted between the pyrochlores containing PGM metals as against those containing non-PGM metals. Additionally, perovskite oxides of the form La[Ni(1-x-y)CoxFey]O3 (where 0≤x≤1 and 0≤y≤1) were synthesized by the co-precipitation method. Many of these perovskites exhibited electron conductivities greater than 0.1S/cm, eliminating the need to add carbon for OER studies and implying the likelihood of making conducting electrodes with these materials without the additives like carbon. The perovskites LaNi0.6Co0.4O3 or LaNi0.6Fe0.4O3 with x/y =0.4 had conductivities of the order of 10S/cm. The electrocatalytic activity for the OER was studied using a rotating disk electrode (RDE) in 0.1M KOH and catalyst loading of ~100μg/cm2. The perovskite LaNi0.5Co0.5O3 (x=0.5, y=0) had the onset potential of ~1.50V against RHE, and all these perovskites had onset potentials ~0.1-0.15V higher than the benchmark IrO2 that has an onset potential of ~1.43V. Few of the perovskites were also evaluated for their oxygen reduction activity (ORR) implying that these materials can be used as bi-functional catalysts.
M.S. in Chemical Engineering, July 2016
Show less

Title: MODELING STRATEGIC COMPETITION, TACTICAL DESIGN, AND OPERATIONAL PLANNING TO IMPROVE SUPPLY CHAIN PERFORMANCE
Creator: Li, Chia-hang
Date: 2017, 2017-05
Description: A supply chain is a network of facilities responsible for the production and delivery of goods and services from the initial raw materials to...
Show moreA supply chain is a network of facilities responsible for the production and delivery of goods and services from the initial raw materials to the end customers. Supply chain management, therefore, involves management of activities both within and among the organizations throughout the chain at every level of business management. In this dissertation, we address three specific supply chain problems at three distinct level of business management: (1) Operational capacity and production planning; (2) Tactical closed-loop channel structure design; and (3) Strategic platform competition. In each work, we identify strategies that lead the supply chain improvements.
Ph.D. in Management Science, May 2017
Show less

Title: MOLECULAR MECHANISMS UNDERLYING SALMONELLA SURVIVAL ON SURFACE OF SELECTED NUTS AND FRUITS
Creator: Li, Ye
Date: 2017, 2017-07
Description: Salmonella enterica is the leading cause of bacterial foodborne illness in the United States. In recent years, S. enterica has been frequently...
Show moreSalmonella enterica is the leading cause of bacterial foodborne illness in the United States. In recent years, S. enterica has been frequently linked to foodborne outbreaks associated with nuts and fruits; however, the underlying mechanisms of such association have not been fully understood. In the first part of this study, we evaluated the impact of various environmental factors and food surface attributes on the attachment and survival of five S. enterica strains representing serotypes Typhimurium, Enteritidis, Montevideo, Mbandanka, and Braenderup on three different raw nuts (i.e. black peppers, almonds and hazelnuts) and two different S. enterica strains including serotypes Typhimurium and Enteritidis on two fresh fruits (i.e. grape tomatoes and cantaloupes) under storage conditions relevant to industrial practice. We observed significant inter-strain variations in S. enterica survival on nut and fruit surface. A direct correlation was found between the nut and fruit surface roughness and S. enterica attachment and survival. Lower relative humidity (20%) and higher storage temperature (25oC) resulted in significant S. enterica reduction on nut shells. Lower storage temperature at 4oC significantly reduced S. enterica population on grape tomatoes. In the second part of this study, we used a newly-developed transposon mutagenesis library in S. enterica serotype Enteritidis genome and highthroughput sequencing analysis to identify genes with potential roles in S. enterica attachment to and survival on almonds and grape tomatoes. A total of 336 and 210 S. enterica genes displayed significant selection on almonds and grape tomatoes over a 7-d storage period at 25oC (p<0.05), respectively. Our results suggest that various food attributes, environmental factors as well as bacterial determinants collectively contribute to the survival and persistence of S. enterica on nuts and fruits, providing new data for future development of knowledge-based intervention strategies.
Ph.D. in Biology, July 2017
Show less

Title: HIGH-FREQUENCY TRADING, LOW-FREQUENCY TRADING AND THE LIMIT ORDER MARKET
Creator: Li, Kun
Date: 2015, 2015-07
Description: The emergence of High-Frequency Trading (HFT) has met with mixed reactions in both investment and academic communities. However, there still...
Show moreThe emergence of High-Frequency Trading (HFT) has met with mixed reactions in both investment and academic communities. However, there still exist gaps on distinguishing and interpreting the impact of HFT on the Low-Frequency Trading (LFT) side. In this thesis, I present three chapters that address the impact of HFT to LFT. I find evidence to distinguish trading generated by HFT in the limit order market, and consequently apply to explore how HFT affects LFT in terms of the liquidity and the order execution quality. In addition, I further explore the fleeting orders generated by HFT and their impact on the liquidity of LFT.
Ph.D. in Management Science, July 2015
Show less

Title: DISTRIBUTED NOSQL STORAGE FOR EXTREME-SCALE SYSTEM SERVICES IN CLOUDS AND SUPERCOMPUTERS
Creator: Li, Tonglin
Date: 2015, 2015-12
Description: As supercomputers gain more parallelism at exponential rates, the storage infrastructure performance is increasing at a significantly lower...
Show moreAs supercomputers gain more parallelism at exponential rates, the storage infrastructure performance is increasing at a significantly lower rate due to relatively centralized management. This implies that the data management and data flow between the storage and compute resources is becoming the new bottleneck for large-scale applications. Similarly, cloud based distributed systems introduce other challenges stemming from the dynamic nature of cloud applications. This dissertation addresses several challenges on storage systems at extreme scales for supercomputers and clouds by designing and implementing a zero-hop distributed NoSQL storage system (ZHT), which has been tuned for the requirements of high-end computing systems. ZHT aims to be a building block for scalable distributed systems. The goals of ZHT are delivering high availability, good fault tolerance, light-weight design, persistence, dynamic joins and leaves, high throughput, and low latencies, at extreme scales (millions of nodes). We have evaluated ZHT’s performance under a variety of systems, ranging from a Linux cluster with 64-nodes, an Amazon EC2 virtual cluster up to 96-nodes, to an IBM Blue Gene/P supercomputer with 8K-nodes. This work also presents several real systems that have adopted ZHT as well as other NoSQL systems, namely ZHT/Q, FusionFS, IStore, MATRIX, Slurm++, Fabriq, FREIDAState, and WaggleDB, all of these real systems have been significantly simplified due to NoSQL storage systems, and have been shown to outperform other leading systems by orders of magnitude in some cases. Through our work, we have shown how NoSQL storage systems can help on both performance and scalability at large scales in such a variety of environments.
Ph.D. in Computer Science, December 2015
Show less

Title: UNIDIRECTIONALLY ALIGNED COLLAGEN / COLLAGEN COMPOSITE FIBRILS AND THEIR MODULATION OF CELL BEHAVIORS
Creator: Li, Wen
Date: 2016, 2016-05
Description: One of the main goals of tissue engineering is to create new functional scaffolds with desired chemical and physical features mimicking the...
Show moreOne of the main goals of tissue engineering is to create new functional scaffolds with desired chemical and physical features mimicking the native micro-environment and modulating cell functions or behaviors. As collagen is abundant in the extracellular matrix (ECM) of native tissues, it is widely used to generate artificial scaffolds in in vitro. In this thesis research, aligned collagen and collagen-composite fibirls (COL-CNT and COLI-COLIII) were achieved via epitaxial growth of collagen on muscovite mica surface. It was found that hdpPSCs interacted with collagen fibrils by deforming the cell shape, harvesting the nearby collagen fibrils, and reorganizing the fibrils around the cell body to transform a 2D matrix to a localized 3D matrix. Such a unique 3D matrix prompted high expression of β-1 integrin around the cell body that mediates and facilitates the stem cell differentiation toward neural cells. By compositing collagen with carbon nanotube (CNT), aligned COL-CNT fibril was obtained with 3 times stiffer than pure collagen fibril and a 2 nm D-period increase. The anisotropic morphology and high stiffness of COL-CNT fibrils greatly facilitated the elongation of SKOV3 cells byregulating the cell-matrix adhesion, cytoskeleton arrangement and cell migration rate, finally promoted the epithelial-mesenchymal transition (EMT) of the SKOV3 cells. Aligned COLI-COLIII hybrid collagen fibrils exhibit higher stiffness than pure COLIII and stronger binding affinity than pure COLI. It is found that with the combined advantages of stiffness and binding affinity, aligned COLI-COLIII fibrils lead to fibroblast cytoskeleton elongation and enhanced cellular elasticity with stronger traction strain sulfured, which improves collagen synthesis ability of fibroblast with a higher collagen I percentage.
Ph.D. in Chemistry, May 2016
Show less

Title: SECURE AND RESILIENT OPERATION OF CYBER-PHYSICAL POWER SYSTEMS
Creator: Li, Zhiyi
Date: 2017, 2017-07
Description: For economic reasons, modern power systems are commonly operated close to their secure limits so that they are vulnerable to unexpected severe...
Show moreFor economic reasons, modern power systems are commonly operated close to their secure limits so that they are vulnerable to unexpected severe disruptions such as disastrous cyberattacks and extreme weather events. This thesis is aimed at enhancing the security and resilience of power supplies for facilitating the development of a Smart Grid, when power systems in various parts of the world have been undergoing transitions toward cyber-physical systems. First, this thesis discusses common cybersecurity vulnerabilities in modern power systems and presents physical implications of cyberattacks on power system operations. In particular, this thesis analyzes a specifc type of coordinated cyberphysical attacks that could lead to undetectable line outages. Coordinated with physical attacks causing line outages, cyberattacks comprising topology preserving and load redistribution attacks could mask and potentially exasperate the outages to trigger cascading failures. Such coordinated cyber-physical attacks are analyzed in a bi-level optimization model which is then transformed into a mixed-integer linear programming problem. The proposed model and the two-stage solution algorithm are examined by case studies based on the IEEE 14-bus and 118-bus test systems. Second, this thesis offers the pertinent studies on quantifying the risk of cybersecurity vulnerabilities in power system operations. A type of locally coordinated cyber-physical attacks is analyzed in detail, which would cause undetectable line outages in local areas without the need for complete network information. A risk-based optimization model in the mixed-integer linear programming form is presented for analyzing physical implications resulting from the power ow redistribution. An efficient greedy search-based heuristic method is then developed to offer satisfactory solutions for real-time applications, which are verified by case studies based on a six-bus system and the two-area IEEE RTS-96 system. Third, this thesis studies security measures for mitigating the cybersecurity risk in power system operations. A game-theoretic framework is built for determining the optimal combination of security measures based on the minimax-regret decision rule. The resulting multi-level optimization model is reformulated as a bilevel mixed-integer linear programming problem. An implicit enumeration algorithm is then developed to achieve an exact solution to this complex problem. Acceleration techniques are also provided to improve the computation efficiency for large-scale power system applications. The proposed model and solution methods are validated by case studies based on a six-bus test system and the two-area RTS-96 system. Fourth, this thesis extends the discussion of cybersecurity vulnerabilities to the operation of distributed power systems like microgrids. Since microgrids are regarded as building blocks of a Smart Grid, they strive for cyber-secure operations for sustaining power services to local customers. The assessment and mitigation of the cybersecurity risk in microgrid operations is then presented in depth. Additional opportunities provided by software-defined networking technologies to enhance the microgrid cybersecurity are also realized by the proposed defense-in-depth framework that comprises three lines of defense against cyberattacks. Last, this thesis investigates the role of networked microgrids in enhancing the power system resilience against extreme events. Since resilience is an intrinsically complex property which requires deep understanding of power system operations, a generic simulation-based framework is developed for power system operators to analyze the resilience comprehensively and respond effectively in emergency conditions. The notion that the deployment of networked microgrids catalyzes the resilience enhancement in a Smart Grid is discussed in detail. Besides, the management of networked microgrids for achieving a higher degree of resilience, reliability, and efficiency of power supplies is discussed based on the proposed hierarchical control framework.
Ph.D. in Electrical Engineering, July 2017
Show less

Title: STEREOTYPE THREAT: THE EFFECT OF MINDFULNESS ON GENDER DIFFERENCES IN SPATIAL REASONING
Creator: Leon, Adeline
Date: 2014, 2014-12
Description: Stereotype threat is a phenomenon in which performance is inhibited due to the psychological threat of an individual’s association with a...
Show moreStereotype threat is a phenomenon in which performance is inhibited due to the psychological threat of an individual’s association with a group believed to underperform on the task at hand (Steele, 1997). Though stereotype threat is typically attributed to race and ethnicity, there is a gender stereotype effect as well, caused by the notion that women are underperformers in spatial reasoning. Mindfulness, with its focus on acceptance and taking a non-judgmental stance, has been associated with broad physical, emotional, and cognitive benefits (Malinowski, 2013) that could counter these negative psychological effects and improve performance during a stereotype threat task. This study explores the relationship between mindfulness and women’s performance on a spatial reasoning task. A total of 256 women were randomly assigned to one of two conditions: a stereotype threat primed group or a stereotype threat non-primed group. The study found no statistically significant relationship between mindfulness, spatial reasoning, and priming. However, future studies based on these findings may still contribute to the literature by including a mindfulness intervention, conducting a similar study in person, or assessing potential benefits of mindfulness in ethnic minorities. These studies may lead to more valuable interventions to overcome the effects of stereotype threat.
M.S. in Psychology, December 2014
Show less

Title: MEASURING DEGREE OF BILINGUALISM AND ITS EFFECT ON COGNITIVE PERFORMANCE
Creator: Leon, Adeline
Date: 2017, 2017-07
Description: Bilingualism is a unique experience that has been shown to have a distinct impact on cognitive performance: disadvantages in language...
Show moreBilingualism is a unique experience that has been shown to have a distinct impact on cognitive performance: disadvantages in language production (Gollan, Montoya, Fennema-Notestine, & Morris, 2005) and advantages in executive functioning skills (Bialystok, Craik, Klein, Viswanathan, 2004; Costa, Hernandez, Sebastian-Galles, 2008). However, some researchers assert that bilingual differences do not exist at all (Kousaie & Phillips, 2012a, 2012b; Paap & Greenberg, 2013). These discrepancies can have a substantial effect on neuropsychological assessment results, diagnoses, and treatment recommendations. The purpose of this study was to measure bilingualism in patients presenting for neuropsychological testing to determine the effect of degree of bilingualism on cognitive performance. Bilingualism was measured in an objective, continuous manner using the Peabody Picture Vocabulary Test (PPVT; Dunn & Dunn, 2007) to assess proficiency in English and the Test de Vocabulario en Imagenes Peabody (TVIP; Dunn, Lugo, Padilla, Dunn, 1986) to assess proficiency in Spanish. This bilingualism index was used to measure the effect of degree of bilingualism on neuropsychological test performance in English/Spanish bilinguals assessed in their dominant language. Archival data from 99 participants presenting for neuropsychological testing were used to examine the bilingualism effect on the following cognitive domains: shifting of set, divided attention, naming, lexical retrieval, and verbal working memory. With the exception of the BNT, results of linear regression analyses revealed no significant effect of bilingualism on cognitive performance in any of the domains measured. Future research may investigate alternative ways to measure bilingualism to facilitate proper diagnosis and treatment recommendations in a clinical population.
Ph.D. in Psychology, July 2017
Show less

Title: NOVEL SUPERCAPACITORS MADE OF ACTIVATED CARBON WITH MECHANICAL ACTIVATION OR THROUGH MICRO-EXTRUSION OF HIGH CONCENTRATION GRAPHENE SLURRIES
Creator: Li, Ling
Date: 2016, 2016-12
Description: The overarching objective of this project is to investigate a novel concept of three - dimensional (3D) supercapacitors (SCs) with 3D...
Show moreThe overarching objective of this project is to investigate a novel concept of three - dimensional (3D) supercapacitors (SCs) with 3D interpenetrating positive and negative electrodes. Such 3D SCs are expected to be able to convert the high energy and high power densities based on the active electrode materials into comparable high energy and high power densities for assembled SCs. The SCs will be fabricated via micro-extrusion method layer by layer. The electrode will be fabricated from graphene/activated carbon (AC)-based materials. We investigated two types of graphene, graphene slurries preparation and characterization in this study. Activated carbon (AC) was processed with different ball milling conditions. The characterization of graphene and activated carbon with different conditions were performed using SEM, BET, TGA, RAMAN, FTIR methods. Galvanostatically cycling and cyclic voltammetry tests were conducted on AC with different conditions. The ball milled 6-hour AC has specific capacitance high up to 102F/g (209μF/cm2) specific. High energy ball milling can induce oxidization of AC which makes the capacity of materials increases.
Ph.D. in Materials Science and Engineering, December 2016
Show less

Title: AN INVESTIGATION INTO FIRE ENDURANCE OF WOOD AS A STRUCTURAL MATERIAL IN TALL BUILDINGS
Creator: Ling, Lei
Date: 2014, 2014-05
Description: With the global growth in using timber as a structural material for tall buildings to respond to the trend of sustainability, several timber...
Show moreWith the global growth in using timber as a structural material for tall buildings to respond to the trend of sustainability, several timber buildings from 7 stories to 10 stories have already been built in Europe and Australia. However, in the United States, timber buildings are still limited to 6 or less stories [2]. The motivation of this thesis is to respond to the proposal for fire safety challenges of tall wood buildings issued by the Fire Protection Research Foundation. Since using timber as a structural material is just underway, more related studies from different academic departments and organizations are required in order to characterize the fire performance of tall timber structures, investigate the related challenges and necessary research to achieve a high level of safety and property protection equal to those offered by concrete or steel structures, and promote the development of this type of building systems. This thesis presents a literature review of global design cases of timber buildings, corresponding calculations of fire-resistance rating, recent and ongoing fire tests, and adhesive effects of timber members. A gap analysis was developed, with current challenges of building timber buildings presented, focusing on structural design, fire protection, durability, and code regulations requirements. This gap analysis was then compared with other similar published papers in an attempt to have a better understanding of what areas of research are needed, and suggesting for further studies to promote the idea of using timber as a structural material for tall buildings.
M.S. in Civil Engineering, May 2014
Show less

repository.iit

Search the repository

Pages

Pages

Enabled Filters

Refine Results

Type

Date

Academic status of creator

Department

Subject

Creator

Part of