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Title: THE IMPACT OF THE JOINT POSTURE ON FINGER NEUROMECHANICS
Creator: Qiu, Dan
Date: 2014, 2014-05
Description: This dissertation presents a series of studies investigating the neuromechanical properties of the index finger with special emphasis on how...
Show moreThis dissertation presents a series of studies investigating the neuromechanical properties of the index finger with special emphasis on how these properties varied with finger posture. A cadaver study was performed to measure the mapping relationship between tendon force and the resulting fingertip force. A strong linear relationship between magnitude of the tendon force and magnitude of the produced fingertip force was confirmed, up to the force levels examined. The finger posture, however, strongly influenced both fingertip force direction and magnitude. Two fundamental hypotheses of finger biomechanical modeling were then tested in further cadaveric studies. The preliminary results supported the assumption of linear superposition of the contributions of individual tendon forces to the overall fingertip force, at least for two muscles up to the force levels tested. It is also confirmed that the index finger force was almost exclusively produced by the muscles of the index finger, with relatively minor contributions from the other compartments of flexor digitorum superficialis (FDS), flexor digitorum profundus (FDP), or extensor digitorum communis (EDC). An in-vivo human subject study was performed to examine muscle activation patterns during isometric fingertip force production across task directions and finger postures. It was shown that significant changes in muscle excitation patterns occurred, especially with variations in interphalangeal (IP) posture. These changes involved fundamental variation in the underlying pattern rather than just scaling of a given activation pattern. An anatomically correct force-based computer model of the index finger was built to study the roles of different structures and characteristics in finger task performance. The model was validated with the cadaver study result to display its reliability in predicting fingertip xiii force and dynamic movement for given tendon forces. The model was then employed to estimate some hard-to-measure variables including joint contact force and joint passive torque components. The simulation of tendon injuries with the model, including Boutonniere deformation and mallet finger, was able to predict the abnormal finger joint movements under these patho-mechanical conditions. The model simulation also suggested that fingertip force capacity was largely maintained after selected tendon pulley excision surgeries.
PH.D in Biomedical Engineering, May 2014
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Title: MOLECULAR MECHANISMS OF ESTROGEN RECEPTOR BETA ACTION IN COLORECTAL CARCINOGENESIS
Creator: Vaz Saleiro, Diana Nora
Date: 2013, 2013-07
Description: Colorectal cancer (CRC) is a major public health problem in the world population, which emphasizes the need to study novel molecular targets...
Show moreColorectal cancer (CRC) is a major public health problem in the world population, which emphasizes the need to study novel molecular targets in order to develop alternative chemopreventive and chemotherapeutic strategies against it. Estrogens have been shown to exert a protective role against CRC and its actions seem to be mediated by estrogen receptor β (ERβ). However, further studies are required to elucidate the role of ERβ in the colon. To achieve this goal, we evaluated the effects of ERβ deficiency in sporadic CRC and colitis-associated CRC (CAC) by using two in vivo models. In addition, we stably transfected RKO colon cancer cells to overexpress ERβ and identify novel molecules regulated by ERβ signaling in vitro. In the sporadic CRC in vivo model, azoxymethane (AOM)-treated ERβ knockout (βERKO) mice showed a significantly higher incidence and multiplicity of colonic preneoplastic lesions compared to AOM-treated ERα knockout and wild-type (WT) mice. These results were associated with a loss of normal colonic crypt organization and a decrease in apoptosis rates suggesting that ERβ is the ER subtype with a protective role against sporadic CRC progression. Confirming this hypothesis, we observed that AOM-treated βERKO mice presented a significantly higher incidence of adenomas than WT mice. By real time-polymerase chain reaction and immunohistochemistry analyses, ERβ-deficient adenomas were shown to be more proliferative and less differentiated than adenomas in WT mice. Furthermore, in the CAC in vivo model, βERKO mice developed more severe clinical colitis compared to WT mice, as evidenced by significantly higher disease activity index, weight to length ratio of the colons, inflammation score, and grade of dysplasia. ERβ-deficient tumors were characterized by a significant increase in pro-inflammatory xv molecules, suggesting that ERβ might exert anti-inflammatory effects in CAC. Moreover, in vitro results revealed a novel molecular mechanism by which ERβ might drive differentiation of goblet cells in the colonic epithelium. Altogether these findings highlight the importance of ERβ in protection against colorectal carcinogenesis and provide a clinical and translational potential to use ERβ selective agonists in order to prevent and/or treat CRC.
PH.D in Biology, July 2013
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Title: RESPONSE STYLE AS A MODERATOR BETWEEN COMBAT EXPOSURE AND PTSD SYMPTOMATOLOGY
Creator: Walton, Jessica
Date: 2011-11, 2011-12
Description: Throughout the literature, combat exposure has been consistently linked to PTSD symptomatology among combat veterans. However, the wayan...
Show moreThroughout the literature, combat exposure has been consistently linked to PTSD symptomatology among combat veterans. However, the wayan individual responds to clinical interactions, also known as their response style, has received little or no attention as a potential moderating variable between combat exposure and PTSD symptomatology. Much of the research in the area of response style has utilized the MMPVMMPI-2 validity scores as a means to detect over-reporting among combat veterans. However, at present, few studies have examined responses on both the MMPI-2 validity scales and the SIRS as they relate to the detection of over-reporting on other measures (i.e., PCL-M and CES). The current study seeks to examine whether the response style on selected MMPI2 F-family validity scales and the SIRS among a sample of Vietnam combat veterans moderates the relationship between combat exposure and PTSD symptom endorsement. Individuals' combat exposure and current PTSD symptomatology were assessed through the use of self-report measures. In addition, participant's response style was assessed through the use of both the MMPI-2 and the Structured Interview of Reported Symptoms (SIRS). The results of the study demonstrated that response style did not moderate the relationship between combat exposure and PTSD symptomatology. However, results did reveal that individual's responses on the SIRS were directly related to PTSD symptom endorsement.
Ph.D. in Psychology, December 2011
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Title: CONTROLLED RELEASE OF VANCOMYCIN FROM A THERMORESPONSIVE HYDROGEL SYSTEM FOR THE PROPHYLACTIC TREATMENT OF POST-OPERATIVE ACUTE ENDOPHTHALMITIS
Creator: Dosmar, Emily
Date: 2017, 2017-05
Description: Current clinical treatment for preventing the post-operative endophthalmitis include a bolus injection of the antibiotic, vancoymin (VAN),...
Show moreCurrent clinical treatment for preventing the post-operative endophthalmitis include a bolus injection of the antibiotic, vancoymin (VAN), during surgery followed by a 1-2-week period of patient administered, topically applied antibiotics. Due to poor patient compliance, drug loss due to poor drug residence time for topically applied drops, and limitations of drug injection sites, there is a clinical need for a subconjunctival, sustained release drug delivery system. While a controlled drug delivery system is beneficial by eliminating patient drug administration and improving drug delivery, the challenges of initial burst (IB), drug release kinetics, and drug distribution must be addressed in order to design an optimal system to address this need. The primary goal of this study was to develop a drug delivery system (DDS) capable of delivering VAN for 10-14 days and replacing both the bolus VAN injection and the topical eye drops. We hypothesized that controlled and extended release of VAN will perform equally or better than bolus VAN administration and eye drops. To accomplish this goal, three specific aims were performed: 1) Development of an injectable drug delivery system to release bioactive VAN for at least 10 days; 2) Validation of the efficacy of the developed DDS; and 3) Development of a compartmental model analysis model used to predict the loading dose required to achieve therapeutic drug concentration in the vitreous.
Ph.D. in Biomedical Engineering, May 2017
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Title: NEW BEAMFORMING AND SPACE-TIME CODING SCHEMES FOR MIMO WIRELESS SYSTEMS
Creator: Tavassoli, Farhad
Date: 2013, 2013-05
Description: Space-time coding and Beamforming are two main techniques utilized in multiple-input multiple-output (MIMO) wireless systems to increase...
Show moreSpace-time coding and Beamforming are two main techniques utilized in multiple-input multiple-output (MIMO) wireless systems to increase channel capacity. In this work, we present new beamforming algorithms and space-time codes for MIMO wireless systems to reduce the complexity and enhance the performance. We present a new framework to obtain beamforming algorithms for code division multiple access (CDMA) and orthogonal frequency division multiplexing (OFDM) systems based on principal component analysis (PCA) approach. Four different PCA objective functions are used as examples to illustrate how to obtain new beamforming algorithms based on the proposed framework. Since two of the objective functions result in the same algorithm, three different beamforming algorithms are obtained for CDMA and OFDM systems. We show that the new algorithms offer a desirable performance while they have considerably lower computational complexity than the optimum algorithms. It is demonstrated that the proposed algorithms also have a fast convergence rate. We also propose new space-time codes for both coherent and non-coherent wireless systems which can provide lower symbol error rates than existing codes in the same class. For the coherent case, we propose a new quasi-orthogonal code to provide a full-rate full-diversity transmission. Unlike the other codes in the literature, the proposed code does not require the transmitted symbols to be chosen from two different constellations. Choosing all symbols from only one constellation reduces the required storage memory to half of that needed in other methods. It also avoids decreasing the minimum distance between the symbols and hence, avoids degrading the coding gain. For the non-coherent case, a new constellation design for differential unitary space-time modulation is proposed. We generate xi a set of unitary matrices from the multiplication of a simple unitary matrix with entries of 1 by diagonal matrices made from quaternary alphabets. Then, the proposed constellation is formed from the product of the optimum matrix chosen from this set and the optimized diagonal matrix first used for the cyclic codes. We show that the proposed constellation yields a larger diversity product as well as a lower union bound for pairwise error probability with the same or lower complexity compared to other existing constellations.
PH.D in Electrical Engineering, May 2013
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Title: NEW DIRECTIONS IN POST-EARTHQUAKE FIRE HAZARD ANALYSIS WITH APPLICATIONS TO MIDWESTERN UNITED STATES
Creator: Farshadmanesh, Pegah
Date: 2017, 2017-05
Description: Post-earthquake fire ignition (PEFI) can lead to severe structural damage following an earthquake. Estimating the risk of such ignitions in...
Show morePost-earthquake fire ignition (PEFI) can lead to severe structural damage following an earthquake. Estimating the risk of such ignitions in buildings and identifying methods to abate it are essential steps in an overall effort to mitigate the impact of post-earthquake fires in urban areas. While several models have been developed for areas with available historical PEFI data, such as the Western United States, no such models have been developed for areas with little or no data specific for post-earthquake fires. Examples of such areas are seismic regions in the Midwestern United States. The lack of PEFI data for these areas is due to the fact that at the time of several significant earthquakes in the early nineteenth century, most earthquake-stricken communities where rural. With the growth of urban areas in the region, a need exists for a methodology that can be effectively used in estimating PEFI risks when no or little historical data is available. In this research, it was found that models for PEFI risk estimation may indeed be developed using available data on ignitions for normal conditions as a basis and then using some type of a modification factor to account for the significance of future earthquakes. This modification factor depends on the characteristics of the region in terms of seismic activities and the type and distribution of buildings and their potential in promoting ignitions. The term “normal condition ignition” (NCI) refers to an ignition that occurs due to everyday activities and routine operations in a building. In a residential building, such activities include, for example, operating heating units and burners, cooking, and mechanical malfunction of appliances. In this research, it was found that four factors specifically affect PEFI risk and can be used to develop models for risk estimation. These are (1) spatial characteristics such as geographic concentration of particular building types; (2) ignitability characteristics, such as the sources of ignitions in a particular building type, (3) earthquake characteristics (such as the peak ground acceleration); and (4) temporal characteristics, such as the time of the earthquake and seasonality. Accordingly, models for estimating the risk of post-earthquake fire ignition occurrence are developed. These models are tested, and the model parameters calibrated, using information in areas for which both the NCI and PEFI data are available (such as in the Western United States). To illustrate the applicability of the models developed and proposed in this study, St. Louis City is considered. This constitutes a major urban area vulnerable to potential future seismic activities because of proximity to the New Madrid Fault Zone. Using the NCI data for this area, PEFI risk values are estimated based on probable future seismic activities in the region. The results are presented in terms of estimated annual risk of post-earthquake fires for the area specifically for residential buildings (such as single or multifamily dwellings). The study further discusses the significance of PEFI models, their limitations and also provides suggestions for the future continuation of the research.
Ph.D. in Civil Engineering, May 2017
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Title: MODERATED MEDIATION OF LEADER'S TRAITS AND EFFECTIVENESS: THE ROLE OF STRESS
Creator: Fearing, Benjamin K.
Date: 2015, 2015-12
Description: The current study examined the relationship between individual differences and leadership effectiveness for 196 leaders informed by prominent...
Show moreThe current study examined the relationship between individual differences and leadership effectiveness for 196 leaders informed by prominent multi-trait models which included the distal traits of cognitive ability and the broad personality traits of extraversion, conscientiousness, neuroticism, and independence and the proximal traits of leadership self-efficacy (LSE) and motivation to lead (MTL). The study also quantified situational moderators in terms of a leader’s role ambiguity and situational constraints. The results supported a significant relationship between affective-identify MTL and leadership effectiveness with LSE as a proximal antecedent to MTL. Results also showed that (a) LSE had an indirect effect on leadership effectiveness through affectiveidentify MTL, (b) role ambiguity moderated the relationship between LSE and affectiveidentity MTL, and (c) the personality trait of independence had an indirect effect on leadership effectiveness through LSE and affective-identity MTL. However, hypotheses related to cognitive resource theory were not supported such that there was not a significant moderating effect of job stress on the relationship between cognitive ability, managerial training, and leadership experience with leadership effectiveness.The current study examined the relationship between individual differences and leadership effectiveness for 196 leaders informed by prominent multi-trait models which included the distal traits of cognitive ability and the broad personality traits of extraversion, conscientiousness, neuroticism, and independence and the proximal traits of leadership self-efficacy (LSE) and motivation to lead (MTL). The study also quantified situational moderators in terms of a leader’s role ambiguity and situational constraints. The results supported a significant relationship between affective-identify MTL and leadership effectiveness with LSE as a proximal antecedent to MTL. Results also showed that (a) LSE had an indirect effect on leadership effectiveness through affectiveidentify MTL, (b) role ambiguity moderated the relationship between LSE and affectiveidentity MTL, and (c) the personality trait of independence had an indirect effect on leadership effectiveness through LSE and affective-identity MTL. However, hypotheses related to cognitive resource theory were not supported such that there was not a significant moderating effect of job stress on the relationship between cognitive ability, managerial training, and leadership experience with leadership effectiveness.
Ph.D. in Psychology, December 2015
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Title: MINIMIZING MAXIMUM PATH DELAY IN MULTIPATH CONNECTIONS
Creator: Devetak, Fabrizio U
Date: 2013, 2013-07
Description: Minimizing packet delay (or packet latency, as it is often called) is an impor- tant goal in modern telecommunication networks. In a network...
Show moreMinimizing packet delay (or packet latency, as it is often called) is an impor- tant goal in modern telecommunication networks. In a network with given physical and topological characteristics, uneven distribution of tra c between nodes may re- sult in parts of the network being underutilized while other parts may experience congestion and its related e ect of higher delays, and even packet loss if bu ers be- come overloaded. Overload results in longer queuing delays, which are a major, if not the major, source of packet delay. Internet nodes typically route based on a single best (shortest) path without taking into account link occupancy and without taking full advantage of all available network resources. So a method for improving network performance is to allow nodes to use multiple paths to route packets to a given desti- nation. In this research project the main objective is to nd the best algorithm that, applied to a multi-commodity network, produces multi-path ow assignments that minimize the maximum cross-network delay. The motivation for this objective is the tighter requirements for quality of service coming from real-time streaming services, such as voice and video, which restrict the maximum source-destination packet delay. An analytical approach, based on Lagrange Multipliers, was investigated which led to the design of an iterative algorithm that can be proved to converge to the opti- mal path and ow con guration. From that algorithm a simpli ed heuristic algorithm was derived, that achieves results close to optimal. Another heuristic but more intu- itive algorithm, similar to the algorithm described in [6], was also investigated and found to also o ers good results and to be computationally e cient. The two heuristic algorithms were simulated with Java programs and, as a benchmark, the single path algorithm that is commonly used in the Internet was also simulated. That simulation was also done with Java programs. Performance comparisons for the three types of simulations is also provided. For a more realistic evaluation, the intuitive heuristic algorithm was also simu- viii lated in the NS-3 simulation environment (in addition to the Java simulation). NS-3 is a state-of-the-art industry standard widely used in the academic world, and for it a distributed routing protocol, that implements the maximum delay minimization algorithms without centralized control, was designed.
PH.D in Computer Engineering, July 2013
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Title: SENTIMENT ANALYSIS BASED ON APPRAISAL THEORY AND FUNCTIONAL LOCAL GRAMMARS
Creator: Bloom, Kenneth
Date: 2011-08, 2011-12
Description: Much of the past work in structured sentiment extraction has been evaluated in ways that summarize the output of a sentiment extraction...
Show moreMuch of the past work in structured sentiment extraction has been evaluated in ways that summarize the output of a sentiment extraction technique for a particular application. In order to get a true picture of how accurate a sentiment extraction system is, however, it is important to see how well it performs at nding individual mentions of opinions in a corpus. Past work also focuses heavily on mining opinion/product-feature pairs from product review corpora, which has lead to sentiment extraction systems assuming that the documents they operate on are review-like | that each document concerns only one topic, that there are lots of reviews on a particular product, and that the product features of interest are frequently recurring phrases. Based on existing linguistics research, this dissertation introduces the concept of an appraisal expression, the basic grammatical unit by which an opinion is expressed about a target. The IIT sentiment corpus, intended to present an alternative to both of these assumptions that have pervaded sentiment analysis research, consists of blog posts annotated with appraisal expressions to enable the evaluation of how well sentiment analysis systems nd individual appraisal expressions. This dissertation introduces FLAG, an automated system for extracting appraisal expressions. FLAG operates using a three step process: (1) identifying attitude groups using a lexicon-based shallow parser, (2) identifying potential structures for the rest of the appraisal expression by identifying patterns in a sentence's dependency parse tree, (3) selecting the best appraisal expression for each attitude group using a discriminative reranker. FLAG achieves an overall accuracy of 0.261 F1 at identifying appraisal expressions, which is good considering the difficulty of the task.
Ph.D. in Computer Science, December 2011
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Title: REAL-TIME INTRUSION DETECTION FOR VOIP OVER WIRELESS NETWORKS
Creator: Tang, Jin
Date: 2012-07-16, 2012-07
Description: Voice over IP (VoIP) has emerged as a prevailing application in recent years. At the same time, with the increasing coverage of the IEEE 802...
Show moreVoice over IP (VoIP) has emerged as a prevailing application in recent years. At the same time, with the increasing coverage of the IEEE 802.11 based wireless networks, VoIP over wireless networks is drawing extensive attention in both academia and industry. Due to the openness and distributed nature of the protocols involved in VoIP over wireless, such as the session initiation protocol (SIP) and the IEEE 802.11 standard, it becomes easy for malicious users in the network to achieve their own gain or disrupt the service by deviating from the normal protocol behaviors. The main objective of this research is to develop real-time intrusion detection techniques that can quickly track down the malicious behaviors which manipulate the vulnerabilities from either VoIP or 802.11 protocols. Further, we will achieve the objective without requiring modification to the relevant standard protocols, and develop analytical tools to guide the detection system design for guaranteed performance. Specifically, for the malicious selfish misbehavior utilizing vulnerabilities of the 802.11 protocol, we design a real-time detector, termed as the fair share detector (FS detector), which exploits the non-parametric cumulative sum (CUSUM) test to quickly find a selfish malicious node without any a priori knowledge of the statistics of the selfish misbehavior. And while most of the existing schemes for selfish misbehavior detection depend on heuristic parameter configuration and experimental performance evaluation, we develop a Markov chain based analytical model to systematically study the FS detector. Based on the analytical model, we can quantitatively compute the system configuration parameters for guaranteed performance. Further, to achieve better detection performance, we enhance the FS detector to develop an adaptive detector with the Markov decision process (MDP). Then based on a reward function defined by us, we are able to determine an optimal decision policy to maximize the overall system benefit through a linear programming formulation. The optimal policy also indicates the operation of the adaptive detector, which yields better performance in both false positive rate and detection delay. For attacks on the SIP layer, we first focus on the well-known flooding attack and develop an online scheme to detect and subsequently prevent the attack, by integrating a novel three-dimensional sketch design with the Hellinger distance detection technique. Also, we address the stealthy attack, where intelligent attackers can afford long time to attack the system, and only incur minor changes to the system within each sampling period. To identify such attacks in the early stage for a timely response, we propose a detection scheme based on the signal processing technique wavelet, which is able to quickly expose the changes induced by the attacks. Moreover, we identify a new type of malformed message attack that can manipulate both the “Session-Expires” header in the SIP message and openness of wireless protocols to severely drain the network resources. We develop a detection method based on the Anderson-Darling test to deal with such attacks. In the future work, we will continue with the CUSUM-based framework for selfish misbehavior detection over practical multi-hop wireless networks with guaranteed performance. It is expected that we can generate distributed CUSUM-based detection mechanisms for the multi-hop networks, analytical tools for the distributed detection system, and configuration parameter selection methods for guaranteed detection performance. Moreover, as attackers can employ the openness of the 802.11 protocols to generate more severe and harder-to-detect attacks to the SIP based VoIP system, to further enhance the detection performance, we plan to develop cross-layer intrusion detection techniques for the system.
Ph.D. in Computer Engineering, July 2012
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Title: WIRELESS SENSOR NETWORK BASED BUILDING AUTOMATION SYSTEM
Creator: Yi, Peizhong
Date: 2012-07-11, 2012-07
Description: Smart grid adds intelligence and bidirectional communication capabilities to today’s power grid, enabling utilities to provide real-time...
Show moreSmart grid adds intelligence and bidirectional communication capabilities to today’s power grid, enabling utilities to provide real-time-pricing (RTP) information to their customers via smart meters. This facilitates customer participation in demand response programs to reduce peak electricity demand. ZigBee, as a wireless technology characterized by low cost, power, data rate, and complexity, is ideal for smart grid applications. Unfortunately, almost all ZigBee channels overlap with Wireless Local Area Networks (WLAN) channels, resulting in severe performance degradation. In this dissertation, firstly, practical ZigBee deployment guidelines under WLAN interference are presented. “Safe Distance” and “Safe Offset Frequency” are identified by means of a comprehensive approach consisting of theoretical analysis, software simulation, and empirical measurement. In addition, a frequency-agility based interference avoidance algorithm is proposed and is implemented. The proposed algorithm detects interference and adaptively switches nodes to “safe” channels dynamically to avoid interference with low latency and energy overhead. Later we propose a real-time residential demand response scheme based on price information provided by ZigBee enabled smart meters. We model the price signal as a random process with known deterministic components, and formulate the problem of cost-minimization as a stochastic scheduling problem. A constraint on the total power consumption is considered to avoid peak shifting. An opportunistic scheduling algorithm consisting of two stages is proposed. Each user is tentatively scheduled based on the optimal stopping approach as if there is no power constraint at the first stage, while the power constraint is taken into account at the second stage. The proposed scheduling algorithm can be implemented in either a centralized or distributed fashion. Simulations validate proposed scheme can evidently reduce the cost of electricity users. At last, an optimal and automatic residential load scheduling scheme with distributed storage system based on our price prediction scheme is proposed. The price prediction scheme forecasts the future 24-hour prices according to day-ahead pricing and RTP history. Our designed scheme adopts integer programming computation to provide simple solution for customers to minimize the total cost including electricity expenditure and storage degradation while satisfying customer time requirement. The performance of proposed scheme is then evaluated through simulation.
Ph.D. in Electrical Engineering, July 2012
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Title: MECHANISMS OF FOAMING, EFFECTS, PREVENTION, AND CONTROL IN ANAEROBIC DIGESTION
Creator: Subramanian, Bhargavi
Date: 2015, 2015-05
Description: Anaerobic digestion (AD) is an essential step to generate energy in the form of biogas from waste. Foaming during AD (AD foaming) is...
Show moreAnaerobic digestion (AD) is an essential step to generate energy in the form of biogas from waste. Foaming during AD (AD foaming) is widespread phenomenon and leads to deterioration of the AD process and operation. In extreme conditions, AD foaming poses a significant safety risk and considerable economic impacts. It is, therefore, necessary to understand the fundamentals of AD foaming to develop effective strategies that can help minimize and prevent the foaming impacts. Several aspects of AD foaming have attracted considerable research attention, however, the focus has been mainly on site specific causes and prevention. The work leading to this thesis was aimed to provide a better understanding of the AD foaming problem, to identify the underlying mechanisms, causes and contributors of foaming and to come up with foam management strategies for full-scale plants. Full-scale cylindrical digester investigations did not identify non-biological factors such as organic loading rate (OLR), mixing, and primary to waste activated sludge (PS:WAS) solids ratio as primary causes of foaming, but foam-causing filaments such as G. amarae and M. parvicella were determined to be primary causes. No foaming was observed over the duration of the study, indicating absence of a primary foaming cause even though the suspected contributors to AD foaming were present. In the case of full-scale egg-shaped digesters (ESD), foaming and foam collapse events were observed over the duration of the study over both during filamentous foaming and non-foaming seasons, indicating that the primary foaming cause requires the contributors to be present. The results of this study demonstrate that ESDs foamed due to high mixing and G. amarae counts above the threshold level (log #6 intersections/mg VSS) in mixed liquor. In both types of digesters, total solids and temperature profiles showed that reducing mixing frequency did not significantly impact digester performance or the homogeneity of the digester contents. Hence, mixing intensity optimization could be an effective strategy in addition to primary cause reduction of foam causing filaments.
Ph.D. in Environmental Engineering, May 2015
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Title: Informal Settings: Implications for Secondary Mathematics Teachers' Abilities to Recognize and Apply Mathematics
Creator: Popovic, Gorjana
Date: 2011-08, 2011-07
Description: The purpose of this study was to describe the ways in which situating learning experiences for mathematics teachers in informal sites,...
Show moreThe purpose of this study was to describe the ways in which situating learning experiences for mathematics teachers in informal sites, specifically in the science museum, assist them in recognizing mathematics in the real world and developing instructional math to help their students make connections between school mathematics and its real world applications. The study took place in the Museum of Science and Industry (MSI), in Chicago, IL. Seven teachers (six female and one male) certified by their state to teach secondary mathematics (grades 6-12), pursuing a Masters in Mathematics Education degree at a private Midwest university, volunteered to participate in the study. Ethnographic methods (e.g., audiotapes of instruction, students’ written work) of data collection and analysis were used to capture teachers’ learning in the context of MSI exhibits (Lave, 1988). Lave’s methodology considers “person-acting (in setting) as an integral unit of analysis” (Lave, 1988, p. 180). Accordingly, the data collection and analysis were organized around two tasks: identifying mathematical concepts represented in the exhibits and creating lesson ideas to address identified mathematical concepts. The data collection included audiotapes of the group discussions around the exhibits, teachers’ Mathematics Concepts and Curriculum Connections (MC3) cards, and teachers’ reflections papers completed at the end of the study. The process of data analysis consisted of multiple interpretative passes through the data. An ethnographically grounded approach to discourse analysis (Gee and Green, 1998) was used as a framework for the analysis across data types. viii The results of the study showed that over the course of the study, teachers began to change their approach to identifying mathematics in the exhibits in two ways. In particular, the teachers realized that the obvious representations of mathematics, such as the appearance of numbers, geometric shapes and geometric figures in the exhibits were not vital to identifying mathematics. Additionally, teachers began to realize that learning about mathematical concepts could be done through exploration of scientific phenomena. The results also showed that once the teachers recognized mathematical concepts in an informal site, they were able to create lessons to address those concepts, as well as to identify where in the curriculum they could use the activities to enhance students’ learning. However, the support of the school administration and curriculum is necessary in order for teachers to incorporate informal education applications into their mathematics instruction.
Ph.D. in Mathematics Education, July 2011
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Title: MICRO-SCALE EHD CONDUCTION-DRIVEN PUMPING AND HEAT TRANSFER ENHANCEMENT IN SINGLE- AND TWO-PHASE SYSTEMS
Creator: Pearson, Matthew
Date: 2011-04-19, 2011-05
Description: Electrohydrodynamic (EHD) pumping methods rely on the interaction between electric fields and the flow fields of a dielectric fluid....
Show moreElectrohydrodynamic (EHD) pumping methods rely on the interaction between electric fields and the flow fields of a dielectric fluid. Conduction pumping is one EHD pumping mechanism, which offers many advantages over other EHD pumping methods (for example, a simple design, no degradation of the working fluid, and no need for a temperature gradient). Conduction pumping can be used in an adiabatic context to pump a working fluid or it can be applied to deliver substantial enhancement to single- and two-phase heat transfer processes. Experimental studies of conduction pumping to date have focused on macro-scale devices with applied voltages on the order of 10 kV. However, like many other EHD concepts, conduction pumping depends primarily on the intensity of the imposed electric field. Therefore, at the micro-scale, the reduced physical size can be accompanied by a reduction in the magnitude of the applied voltage to levels that are significantly more manageable. Furthermore, the simplicity of EHD conduction pumps, such as the lack of moving parts, high reliability, and physical compactness, make them an attractive method for pressure generation in micro-scale fluid and heat transfer devices. This experimental study examines the fundamental behavior and performance of EHD conduction pumping at the micro-scale. The pump is embedded in a rectangular, adiabatic micro-channel, and the single-phase flow and pressure generation of the pump are characterized. The EHD pumping of single- and two-phase flows in micro-channels in the presence of heat transfer is also studied and the corresponding enhancement to single- and two-phase heat transfer is quantified. In an additional study, micro-scale electrodes are embedded within a flat, heated surface to examine the ability of the conduction pump to provide electrically-enhanced wetting of the heated surface during pool boiling. A model based on hydrodynamic instability theory is generated to quantify the influence of the EHD conduction pumping on the pool boiling critical heat flux. Finally, this technology is incorporated into two unique, novel, heat transport devices akin to a heat pipe but in which the primary driving force for the liquid is conduction pumping, not capillarity.
Ph.D. in Mechanical and Aerospace Engineering, May 2011
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Title: DIGITAL CONTROL OF 2-QUADRANT AND 4-QUADRANT SWITCHED RELUCTANCE MOTOR DRIVES
Creator: Shao, Baiming
Date: 2011-04-19, 2011-05
Description: Switched reluctance machines (SRMs) are attractive because of their manufacturing simplicity and high reliability. They do not have any...
Show moreSwitched reluctance machines (SRMs) are attractive because of their manufacturing simplicity and high reliability. They do not have any windings or permanent magnets on the rotor, which makes them robust and easy to maintain. On the other hand, SRMs are highly non-linear since they work in saturation. This causes problems such as high torque ripple and system noise. In addition, mutual inductance needs to be considered for the high performance systems such as electric vehicle or aerospace applications. This effect could become critical when more than one phase is conducting. This also makes them difficult for modeling and control. Significant research on different SRM control techniques has been done in order to improve the performance of the controller and present a good solution for the industrial applications with a reasonable cost. Conventional control techniques for SRMs include chopped current control (CCC), angular position control (APC), and pulse-width modulation (PWM). Proportional-integral (PI) and other linear controllers are also used in the drive systems. However, because of the non-linearity of the machine, classic linear control techniques are not ideal for SRMs as they have challenging control issues in wide speed ranges. Different methods have been presented to implement non-linear control techniques for SRM drives or linearize the SRM motor equations. Many SRM controllers are using one or more look-up tables. The behavior of the controller is adjusting in real-time depending on the data in the look-up tables. This could increase the cost and complexity of the system. In this Ph.D. dissertation, an advanced digital control concept is presented for SRMs in both motoring and generating modes. By treating the system digitally, the controller switches between two pre-defined states to get the desired output. The proposed control technique does not need any look up tables, is not sensitive to the motor parameter variations, is low cost, and has a wide speed range. Simulation and experimental results are presented to verify the proposed digital control approach.
Ph.D. in Electrical and Computer Engineering, May 2011
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Title: EXECUTIVE FUNCTION AND DEPRESSIVE SYMPTOMS IN PATIENTS WITH ISCHEMIC STROKE
Creator: Marola, Jennifer
Date: 2013, 2013-07
Description: Previous research has demonstrated impairment following stroke, including depressive symptoms (Herrmann et al., 2011; O'Brien et al., 2003;...
Show morePrevious research has demonstrated impairment following stroke, including depressive symptoms (Herrmann et al., 2011; O'Brien et al., 2003; Robinson, 2006; Robinson & Spalletta, 2010; Teper & O'Brien, 2008) and cognitive impairment, particularly in executive function (Canning, Leach, Stuss, Ngo, & Black, 2004; Carew, Lamar, Cloud, Grossman, & Libon, 1997; Garrett et al., 2004; Kertesz & Clydesdale, 1994; Lafosse et al., 1997; Madureira, Guerreiro, & Ferro, 2001; Padovani et al., 1995; Su, Lin, Kwan, & Guo, 2008). Current research is limited by the use of primarily patients in the hospital with multiple types of stroke and physical impairment. Additionally, a conceptualization of executive function by Stuss and colleagues (Stuss, Shallice, Alexander, & Picton, 1995) has not been thoroughly investigated utilizing factor analytic techniques. The current study attempted to expand research on executive function and depressive symptoms in individuals with ischemic stroke. This study examined performance on measures of executive function, memory, language, and visuospatial ability, along with measurement of depressive symptoms in participants with ischemic stroke and healthy matched control participants. Results revealed that participants with stroke performed significantly worse in all cognitive domains than control participants. More specifically, in participants with stroke, executive function was more impaired than memory, language, and visuospatial ability. A regression analysis did not find that depressive symptoms accounted for additional variance in executive function above x demographic factors. Two and three factor models of executive function were not supported; the data more closely resembled a one factor model of executive function.
PH.D in Psychology, July 2013
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Title: THE RELATIONSHIP BETWEEN ACCULTURATION AND HELP SEEKING ATTITUDES AND BEHAVIOR OF ASIAN INDIANS IN THE UNITED STATES
Creator: Beri, Reema S.
Date: 2012-04-22, 2012-05
Description: The Asian Indian population in the United States continues to expand rapidly. At the same time, little research exists that has examined the...
Show moreThe Asian Indian population in the United States continues to expand rapidly. At the same time, little research exists that has examined the overall mental health needs of this group or how their level of acculturation affects their help seeking attitudes and behaviors. Research on Asian Americans (of which Asian Indians are a sub-group) that has assessed how acculturation affects help seeking attitudes and utilization behavior has yielded inconsistent results. One possible explanation for the discrepant findings may be due to the way acculturation has been conceptualized and measured. Specifically, most studies have measured acculturation unilinearly, while current research shows that acculturation may be best measured as a bilinear construct. The purpose of the present study was to assess the influence of acculturation on the help seeking attitudes and professional utilization behavior of Asian Indians living in the United States using a bilinear measure of acculturation. The study sample consisted of 266 Asian Indians currently living in the United States. Acculturation was assessed bilinearly using the Asian American Multidimensional Acculturation Scale (AAMAS; Chung, Kim & Abreu, 2004), that allowed for classification into one of four acculturation groups: integrated, assimilated, separated, and marginalized. Help seeking attitudes was measured using the Inventory of Attitudes Toward Seeking Psychological Services (IASMHS; Mackenzie, Knox, Gekoski & Macaulay, 2004), and a demographic questionnaire assessed utilization behaviors and participants’ backgrounds. Results indicate that integrated and assimilated individuals demonstrated more positive help seeking attitudes than separated and marginalized individuals, while no difference was found among the groups in terms of their professional utilization behavior. Implications of the findings and suggestions for future research are discussed.
Ph.D. in Psychology, May 2012
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Title: TEMPERAMENT AND PARENTING: DO THEY INFLUENCE EACH OTHER AND SOCIAL COMPETENCE?
Creator: Strickland, Jennifer Pierce Munson
Date: 2012-04-19, 2012-05
Description: The aim of this study was to examine the reciprocal relationship between parenting behaviors (support, hostility, and scaffolding) and child...
Show moreThe aim of this study was to examine the reciprocal relationship between parenting behaviors (support, hostility, and scaffolding) and child temperament (effortful control, EC, and negative affect, NA) in children during the transition from kindergarten to first grade. Another aim was to examine direct and indirect effects of parenting and child temperament on children’s social competence. Participants included a diverse, community sample of 580 children and their primary caregivers. Parent support and hostility were assessed with the Parent Behavior Inventory. Scaffolding was assessed with observer ratings based on the NICHD ECCRN 3-Boxes Task. Child NA and EC were measured by parent-report using the Child Behavior Questionnaire, and social competence was assessed with the Social Skills Rating System. All measures were administered at both ages. Results indicated that the model that included cross-paths between the parenting and child factors provided the best fit to the data. The path coefficients indicated that child EC had significant effects on parenting behaviors (support, hostility and scaffolding). Contrary to expectation, however, there were no significant paths from parenting to child temperament. Both child EC and parenting support had significant direct and indirect effects on child social competence. Implications of the findings and suggestions for future research are discussed.
Ph.D. in Psychology, May 2012
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Title: TOPICS IN STATISTICAL MODELING AND OPTIMAL DESIGN
Creator: Li, Yiou
Date: 2014, 2014-07
Description: In this dissertation we discuss several topics in statistics concerning regression models, experimental design and optimization. When it is...
Show moreIn this dissertation we discuss several topics in statistics concerning regression models, experimental design and optimization. When it is expensive to compute a function value via numerical simulation, obtaining gradient values simultaneously can improve model e ciency. In the rst and second parts, polynomial regression models with gradient information are considered. We propose an orthogonal polynomial basis with respect to an inner product involving gradients of functions, to eliminate the illconditioning of the design matrix caused by Hermite polynomial basis. Through a simpli ed nuclear reactor model, we show that compared with Hermite polynomial basis, the orthogonal polynomial basis results in a better-conditioned design matrix, and a signi cant improvement when basis polynomials are chosen adaptively, using a stepwise tting procedure. In the second part, the design problem for polynomial regression models with gradient information is addressed. A theoretical upper bound is derived on the scaled integrated mean squared error in terms of the discrepancy of the design, and this bound can be used to choose designs that are both e cient and robust under model uncertainty. Numerical experiments show that low discrepancy designs, whose empirical distribution functions match a xed target distribution, outperform random and Latin hypercube designs. Considering a speci ed regression model, we propose a relaxed optimization problem, which is a semide nite programming problem, to nd the optimal design that minimizes scaled integrated mean squared error. Numerical examples demonstrate the eligibility of the method by showing that the optimal designs we achieve coincide with the already known optimal designs for regression model without gradient information. In the third part of the dissertation, the optimal layout of wind farm is considered. To maximize the expected annual pro t gained by the wind farm, we seek for both optimal number of wind turbines and optimal positions of wind turbines based on Jensen's model. Wind speed and direction are considered as random variables with distribution approximated by empirical distribution from real data. We propose using particle swarm optimization to solve for the optimal layout of wind farm. At last, the situation that more wind turbines are added to an existing wind farm is discussed.
Ph.D. in Applied Mathematics, July 2014
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Title: International Bond Portfolio: Evidence from Emerging Markets
Creator: Wang, Jinghua
Date: 2012-08-20, 2012-07
Description: Allocating capital to fixed income instruments issued by emerging markets (EMs), governments may provide significant benefits to both the...
Show moreAllocating capital to fixed income instruments issued by emerging markets (EMs), governments may provide significant benefits to both the investors and issuers of these instruments. For investors, emerging market instruments may offer a significant risk premium relative to conventional investments in developed markets (DMs) bonds. Furthermore, EMs bonds offer potential diversification benefits because these bonds are not strongly correlated with DMs instruments. For emerging market government issuers, access to global fixed income markets is likely to improve liquidity and offer lower borrowing costs relative to a strategy focused purely on the domestic market. Access to global capital provides these governments with the opportunity to invest in infrastructure projects that promote economic growth and development. Over the past fifty years, economic growth in emerging markets has been supported by investments in capital and technology from the developed world. The benefit of this development for the emerging markets, as measured by growth in income, employment, and wealth, is immediately apparent. There have also been significant advantages for the developed world through opportunities for higher risk adjusted returns from investments in emerging markets. For the most part, the benefits of diversification into emerging markets have focused on equity markets. In this dissertation, the focus is on investments in fixed income instruments. Specifically, the dissertation explores the performance benefits of DMs combined with EMs. It first identifies the potential diversification and describes the financial integration for incorporating EMs bonds into DMs government bond portfolios. In the second phase, it constructs the dynamic linear regression models and conducts the mean-variance tests to demonstrate the incremental benefit of the strategy. In the last phase, a robust test examines the strength of bond portfolio performance between DMs with EMs and the U.S. 7-10 year government bond index. The empirical analysis in this dissertation focuses on three DMs sources of bonds and four EMs regions. Since the EMs are evolving rapidly, and since the global financial markets have also been subject to erratic fluctuations during the global financial crisis, the empirical models employed in the dissertation do not rely on stationarity assumptions. Instead, Kalman Filter (KF) procedures are employed that generate the time-varying coefficients in the multi-factor models in response to new conditions in the markets. The outputs from the KF are used as inputs in the factor model, and the outputs from the factor models are used as inputs in a Markowitz style mean-variance optimization model. This study explores the benefits of the diversification of global government bond portfolio, and provides complete performance evaluations of DMs with or without EMs. The study examines: i) the benefits of inclusion of EMs bonds in DMs; ii) the degrees of financial integration among the research markets; iii) the correlation of the macro-economic factors in the multi-factor models; iv) the relative bond returns of dynamic factor models with time-varying coefficients; and v) the robust tests of bond portfolio performance between DMs with EMs and bond index. The results of this study provide important implications for global investors by identifying diversification gains in EMs.
Ph.D. in Management Science in Finance, July 2012
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