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Title: NON-GAUSSIAN STOCHASTIC DYNAMICS: MODELING, SIMULATION, QUANTIFICATION AND ASSIMILATION
Creator: Gao, Ting
Date: 2015, 2015-05
Description: Motivated by real world applications, three topics - deterministic quantities, uncertainty quantification and data assimilation, are...
Show moreMotivated by real world applications, three topics - deterministic quantities, uncertainty quantification and data assimilation, are considered for non-Gaussian stochastic dynamics. More specifically, three problems are formulated to investigate non-Gaussian dynamics: (i) exit problem and time-dependent probability density; (ii) parameter and function estimation for stochastic differential equations driven by L´evy motion; and (iii) nonlinear data assimilation to infer transition phenomena. First, numerical algorithms are developed to study important metrics: mean exit time, escape probability and time-dependent probability density, which can be utilized to quantify dynamical behaviors of stochastic differential equations with non- Gaussian -stable L´evy motion. Moreover, detailed numerical analysis work is done to ensure the algorithms accurate, fast and stable considering the singular nature of the L´evy jump measure. Second, new approaches on parameter and function estimation in stochastic dynamical systems are devised. Taking advantage of observations on mean exit time, escape probability or probability density, model uncertainty can be quantified by some optimization methods. These methods are beneficial to systems for which mean exit time, escape probability or probability density are feasible to observe. Finally, nonlinear data assimilation on non-Gaussian models is studied. For continuous-discrete filtering, a recursive Bayesian approach is used, and for continuous filtering, Zakai equation is solved to provide the system state estimation. In both cases, time-dependent transition probability between metastable states are investigated. xiMotivated by real world applications, three topics - deterministic quantities, uncertainty quantification and data assimilation, are considered for non-Gaussian stochastic dynamics. More specifically, three problems are formulated to investigate non-Gaussian dynamics: (i) exit problem and time-dependent probability density; (ii) parameter and function estimation for stochastic differential equations driven by L´evy motion; and (iii) nonlinear data assimilation to infer transition phenomena. First, numerical algorithms are developed to study important metrics: mean exit time, escape probability and time-dependent probability density, which can be utilized to quantify dynamical behaviors of stochastic differential equations with non- Gaussian -stable L´evy motion. Moreover, detailed numerical analysis work is done to ensure the algorithms accurate, fast and stable considering the singular nature of the L´evy jump measure. Second, new approaches on parameter and function estimation in stochastic dynamical systems are devised. Taking advantage of observations on mean exit time, escape probability or probability density, model uncertainty can be quantified by some optimization methods. These methods are beneficial to systems for which mean exit time, escape probability or probability density are feasible to observe. Finally, nonlinear data assimilation on non-Gaussian models is studied. For continuous-discrete filtering, a recursive Bayesian approach is used, and for continuous filtering, Zakai equation is solved to provide the system state estimation. In both cases, time-dependent transition probability between metastable states are investigated.
Ph.D. in Applied Mathematics, May 2015
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Title: TOWARDS COMPREHENSIVE COUNTERMEASURES AGAINST CYBER ATTACKS TO IMPROVE SYSTEM SURVIVABILITY
Creator: Wang, Li
Date: 2012-11-20, 2012-12
Description: Survivability refers to the capability of a system to ful ll its mission, in a timely manner, in the presence of attacks, failures, or...
Show moreSurvivability refers to the capability of a system to ful ll its mission, in a timely manner, in the presence of attacks, failures, or accidents. For many distributed systems, ensuring their survivability under directed attacks is critical. Tra c analysis, conducted by the attacker, could reveal the protocol being carried out by the components. Furthermore, having inferred the protocol, the attacker can use the pattern of the messages as a guide to the most critical components. In this thesis, we rst thwart these directed attacks by using message forwarding to reduce tra c di erences, thus diverge attackers from directed attack to random attack, which probabilistically prolongs the availability of important components in the system. Then, we investigate how to improve system availability when the system is under random attack. Although the attackers cannot di erentiate the di erences between critical and non-critical components, they can intelligently decide how to invest their resources by rationally selecting the number of components to attack. Under this case, how to maintain system reliability is another challenging issue. This thesis further discusses the attacker-defender problem and analyzes how to maximize system reliability under rational attacks. When one or more system processing elements are compromised by attackers, how to select applications and deploy their tasks to the remaining processing elements so that the system availability is maximized is also investigated in this thesis. To be more speci c, we assume the applications may have di erent values towards system availability and may or may not share the same composing tasks, and we presented two di erent approaches, i.e., Genetic Algorithm (GA) based approach and Max-Min-Min based approach to solving this problem. GA-based approach produces near optimal solutions and it can be used o -line when the performance is important and timing complexity is not the primary concern. While the Max-Min-Min based approach is computationally e cient and it is used when the timing is critical.
PH.D in Computer Science, December 2012
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Title: OPERATION AND PLANNING OF COORDINATED NATURAL GAS AND ELECTRICITY INFRASTRUCTURES
Creator: Zhang, Xiaping
Date: 2015, 2015-07
Description: Natural gas is becoming rapidly the optimal choice for fueling new generating units in electric power system driven by abundant natural gas...
Show moreNatural gas is becoming rapidly the optimal choice for fueling new generating units in electric power system driven by abundant natural gas supplies and environmental regulations that are expected to cause coal-fired generation retirements. The growing reliance on natural gas as a dominant fuel for electricity generation throughout North America has brought the interaction between the natural gas and power grids into sharp focus. The primary concern and motivation of this research is to address the emerging interdependency issues faced by the electric power and natural gas industry. This thesis provides a comprehensive analysis of the interactions between the two systems regarding the short-term operation and long-term infrastructure planning. Natural gas and renewable energy appear complementary in many respects regarding fuel price and availability, environmental impact, resource distribution and dispatchability. In addition, demand response has also held the promise of making a significant contribution to enhance system operations by providing incentives to customers for a more flat load profile. We investigated the coordination between natural gas-fired generation and prevailing nontraditional resources including renewable energy, demand response so as to provide economical options for optimizing the short-term scheduling with the intense natural gas delivery constraints. As the amount and dispatch of gas-fired generation increases, the long-term interdependency issue is whether there is adequate pipeline capacity to provide sufficient gas to natural gas-fired generation during the entire planning horizon while it is widely used outside the power sector. This thesis developed a co-optimization planning model by incorporating the natural gas transportation system into the multi-year resource and transmission system planning problem.This consideration would provide a more comprehensive decision for the investment and accurate assessment for system adequacy and reliability. With the growing reliance on natural gas and widespread utilization of highly efficient combined heat and power (CHP), it is also questionable that whether the independent design of infrastructures can meet potential challenges of future energy supply. To address this issue, this thesis proposed an optimization framework for a sustainable multiple energy system expansion planning based on an energy hub model while considering the energy efficiency, emission and reliability performance. In addition, we introduced the probabilistic reliability evaluation and flow network analysis into the multiple energy system design in order to obtain an optimal and reliable network topology.
Ph.D. in Electrical and Computer Engineering, July 2015
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Title: CONSIDERING THE FORM OF TALL BUILDINGS TO ACHIEVE MINIMUM STRUCTURAL WEIGHT REGARDING ALONG WIND EFFECT
Creator: Alaghmandan, Matin
Date: 2014, 2014-07
Description: One of the most influential parameters in structural design of tall buildings, in addition to gravity loads, is the lateral load resulting...
Show moreOne of the most influential parameters in structural design of tall buildings, in addition to gravity loads, is the lateral load resulting from wind and to some extend earthquakes. Tall buildings have to be designed for a larger base shear, resulting from wind forces rather than from seismic forces; however, ductile detailing is used when needed to account for seismic demands. The wind effect occurs primarily in two main modes of action: across wind and along wind. Wind also produces three different types of effects on tall buildings: static, dynamic, and aerodynamic. Structurally, static effect is measured independent of time, while dynamic analysis takes into account the system responses to the changes through the period of time. When the building is flexible, it interacts with the wind load and affects its response, which is called aerodynamic effect. To reduce the static and dynamic impact, there are two main solutions: Architectural and Structural. Architects can mitigate wind effect on tall buildings by designing the form aerodynamically or at least by utilizing aerodynamic modifications, which are categorized in macro and micro modifications such as tapering and setback. Structural engineers can reduce wind effect by choosing and designing efficient structural systems regarding the form of the buildings such as tube systems and diagrid system. This thesis, by utilizing the architectural and structural strategies to reduce wind effect, introduces a new design method in the realm of tall buildings. An innovative design method of tall buildings calls for an integrated approach with considerations for both architectural and structural design requirements and concepts. This design method which considers integrated architectural and structural concepts to reduce the along wind effect, for this particular research, is an effort to achieve the minimum weight of the structure. This method creates an innovative computational workbench to design efficient tall buildings, regarding the along wind effect. This can be achieved by connecting an architectural parametric design procedure in AutoLisp (AutoCAD) to generate the models with different forms of modifications, a Computational Fluid Dynamics program (ANSYS) to do the CFD simulations, a structural analysis program (SAP2000) and the ParaGen visualization interface to consider and compare the results to evaluate the models regarding the criteria such as weight of the structure (ParaGen has also a Genetic Algorithm based optimization procedure that is not used in this research). In this research, the most important architectural and structural parameters of seventy-three of the tallest buildings are also studied. Based on the information gathered, the future trend in the geometry and form and also the structural design used for tall buildings can be predicted. It is necessary to mention, based on the past and current trends in architectural features and structural design of tall buildings, and also the future prediction, the required architectural and structural parameters for an innovative proposed design method can be helped. However, it is not clear whether this trend is in a right way or not, it has to be improved based on the architectural and structural efficient parameters. The research shows that a careful study of core design concepts in architectural features and structural design of tall buildings, along with an integrated approach considering various design requirements, can be an effective method in design of new generation of tall buildings.
Ph.D. in Architecture, July 2014
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Title: CONSTRUCTIONS IN NON-ADAPTIVE GROUP TESTING STEINER SYSTEMS AND LATIN SQUARES
Creator: Balint, Gergely `greg' T.
Date: 2014, 2014-05
Description: This thesis explores and introduces new constructions for non-adaptive group testing which are particulary important for the parameter range...
Show moreThis thesis explores and introduces new constructions for non-adaptive group testing which are particulary important for the parameter range we encounter in real life problems. After a summary of existing results, the rst part of this thesis introduces our own constructions, the Latin Square Construction and the Column Augmented Concatenation. Both of these constructions take existing good group testing matrices to create test matrices of larger dimensions. These new matrices are easy to nd for the practical small parameter range we are most interested in. We also address and prove asymptotic results of our Latin Square Construction. In case of the Column Augmented Concatenation the asymptotic results depend greatly on the codes used for the construction. The second part of our work is to address possible ways of augmentation of the Latin Square Construction. Here we explore the di erence in augmentation based on the properties of the starting matrix. In the appendices we give tables of best matrices coming from our constructions with xed, small column weights. We also give a list of the known best 2-disjunct matrices for small row numbers.
PH.D in Applied Mathematics, May 2014
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Title: A COMPRHENSIVE MECHANISTIC STUDY OF PEPTIDOMIMETICS ON MODEL MEMBRANE SYSTEMS
Creator: Bianchi, Christopher P.
Date: 2014, 2014-12
Description: Peptidomimetics are a broad class of structural variant synthetic mimics of antimicrobial peptides (AMPs). AMPs are natural antibiotics found...
Show morePeptidomimetics are a broad class of structural variant synthetic mimics of antimicrobial peptides (AMPs). AMPs are natural antibiotics found in almost entirety throughout all living organisms. Although, AMPs were once thought of as promising therapeutics to combat infectious bacteria, key shortcomings such as low bioavailability, as well as high manufacturing costs have prevented them from reaching a clinical market. Peptidomimetics capitalize on the characteristics of AMPs thought to be responsible for their antibacterial activity, such as net cationic charge and amphiphilicity, while introducing key structural differences. The principal mode of antibacterial activity of AMPs is causing disruption to the bacteria cell membrane of both Gram-positive and Gram-negative bacteria types. The complexities of cell membranes with their various lipid molecule species and proteins makes it difficult to determine mechanistic details of AMPs. It is for this reason model membrane systems such as Langmuir monolayers and supported bilayers composed of the lipid species found in that of actual cell membrane are used. In the present work we have investigated the mechanism of action of different types of peptidomimetics such as N-substituted glycines (peptoids) and oligomers of acylated-lysines (OAKs) on model bacteria and cancer cell membrane systems using various experimental techniques, such as epifluorescence microscopy (EFM), atomic force microscopy (AFM), X-ray reflectivity, and grazing incidence X-ray diffraction (GIXD). From these studies structure function relationships can be obtained, which help aid in the design of new and more effective peptidomimetics. Through these investigations it was found that the substitution of hydrogen atoms for fluorine atoms in the phenyl side chains of cyclic peptoids increases antibacterial on both Gram-positive and Gram-negative model membrane systems, guanidino containing side chains compared to amino containing side chains in α-peptide-β-peptoid chimeras show greater activity on model membrane systems mimicking the cytoplasmic membrane of both Gram-positive and Gram negative bacteria. In addition, insights were gained on the anticancer mechanisms of the naturally occurring AMP magainin-2 and OAK C12K-7α8. The significance of the model membrane system being used cannot be overstated, when the overall arching goal is to bring these peptidomimetics to a clinical market. Thus, the biological relevance of the model membrane system is of great importance. It is this motivation that has lead our research group to develop a floating planar lipid bilayer that is bound to a lipid monolayer functionalized with polyethylene glycol, which to our knowledge has not been previously done. This system and the planar Langmuir monolayer that were used in this work are ideal systems for the use of high energy X-rays that are produced from synchrotron radiation facilities. From such measurements as X-ray reflectivity (XR) and grazing incidence X-ray diffraction (GIXD) molecular scale resolution of the peptidomimetic interactions with the model membrane systems can be achieved.
Ph.D. in Physics, December 2014
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Title: SYSTEMATIC FINANCE: ESSAYS ON ETHICS, METHODOLOGY AND QUALITY CONTROL IN HIGH FREQUENCY TRADING
Creator: Van Vliet, Benjamin Edward
Date: 2012-04-18, 2012-05
Description: A firm is in a state of strategic competitiveness if it has a plan that it rationally and responsibly believes is capable of success. In the...
Show moreA firm is in a state of strategic competitiveness if it has a plan that it rationally and responsibly believes is capable of success. In the age of automation, what justifies a trading firm’s belief in its strategic competitiveness has changed. Rational and responsible belief in the capability of the firm’s trading strategies can be justified by a prudent process that defines conditions for both initial and sustained belief. The process of developing trading systems is itself systematic and a source of competitive advantage. In this thesis, I present three chapters that address strategic competitiveness in automated trading—ethics, methodology and quality control. These chapters examine responsibility, and develop processes for both initial and sustained belief in the competitiveness of trading systems and the trading firm.
Ph.D. in Management Science, May 2012
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Title: LIVE LOAD FACTORS FOR CONTINUOUS GIRDER BRIDGES
Creator: Wang, Qing
Date: 2016, 2016-07
Description: Live load factors of Strength I limit state for continuous girder highway bridges are calibrated based on reliability concept adopted by...
Show moreLive load factors of Strength I limit state for continuous girder highway bridges are calibrated based on reliability concept adopted by AASHTO LRFD and LRFR specifications. A uniform reliability is maintained for multi-girder highway bridges with various span lengths. WIM data, gathered by California, Michigan, New York, Oregon, and Illinois State Department of Transportation are analyzed. Live load effects produced by WIM data are calculated using influence lines. Expected maximum live load effects in given periods are modeled and extrapolated by Gumbel distribution. A relativecalibration formula is developed in order to derive live load correction factors for designing/evaluating continuous highway bridges at a reliability level that is in consistent with simply supported highway bridges. Computer programming is conducted for data sorting and traffic statistical analysis.
Ph.D. in Civil Engineering, July 2016
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Title: ADULTS WITH SICKLE CELL DISEASE: THE DISEASE'S IMPACT ON PAIN NEUROPSYCHOLOGICAL DYSFUNCTION AND QUALITY OF LIFE
Creator: Vernale Iii, Michael A.
Date: 2013, 2013-07
Description: The primary aim of this study is to address the neuropsychological functioning of adults with Sickle Cell Disease (SCD) by examining the...
Show moreThe primary aim of this study is to address the neuropsychological functioning of adults with Sickle Cell Disease (SCD) by examining the association of illness-related and psychosocial factors with cognition. The neuropsychological functioning of adults with SCD will be compared to that of controls matched on gender, race, and age. There is considerable evidence for neuropsychological complications associated with SCD (Anie, 2005; Schatz, 2004). Much of the cognitive deficits are thought to be the result of cerebrovascular accidents commonly suffered by this population. Studies of cognition in children with SCD suggest that cognitive complications tend to increase with age. Particularly implicated are deficits in attention, concentration, and executive functioning. Although the specific neuropsychological morbidity is not as clearly understood for adults with SCD as it is for children, global cognitive impairment within this population has been documented. In addition, pain negatively affects cognitive functioning in both children and adults (Libon et al., 2010). The pattern of impairment was suggested to be the result of additional demands on attentional capacity. However, the relationship between pain and cognitive performance in adults with sickle cell disease is less clear. As a result of frequent pain, individuals with SCD often report a low evaluation of quality of life particularly as a result of health complaints (Anie, 2005). Thus, the inter-dynamic of health -related quality of life, pain , and cognitive dysfunction is not entirely clear within the sickle cell population and therefore warrants examination.
PH.D in Psychology, July 2013
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Title: ANTIBODY AND PEPTIDE CONJUGATES OF BIFUNCTIONAL CHELATORS FOR TARGETED CANCER THERAPY AND IMAGING
Creator: Kang, Chi Soo
Date: 2014, 2014-07
Description: A bifunctional ligand that can rapidly form a stable complex with a metal while conjugated to a tumor-targeting moiety is essential for...
Show moreA bifunctional ligand that can rapidly form a stable complex with a metal while conjugated to a tumor-targeting moiety is essential for targeted therapy and imaging of cancer. New bifunctional chelators in the NETA and DEPA series were developed for targeted radiation cancer therapy. The chelators showed rapid complexation kinetics with 90Y and 177Lu, and the corresponding radiolabeled complexes were stable in vitro and in vivo. Trastuzumab, Panitumumab, and c(RGDyK) conjugates (targeting HER-2, HER-1, and integrin αvβ3, respectively) of the novel bifunctional ligands were prepared. The conjugates displayed fast complexation kinetics with 90Y, 177Lu, and 205/6Bi, and the antibody and peptide conjugates labeled with 90Y, 177Lu, or 205/6Bi exhibited excellent stability and tumor targeting in mice bearing human colorectal cancer (LS-174T). Transferrin (Tf) and bile acid (BA) conjugates of novel chelators in the NE3TA series were prepared for targeted iron chelation therapy (ICT) and positron emission tomography (PET) imaging applications of cancer. Tf and BA conjugates of NE3TA had high cytotoxicity on HeLa, HT29, and PC3 cancer cells. The Tf-N-NE3TA and BA-N-NE3TA also displayed rapid complexation kinetics with 64Cu, and the Tf and BA conjugates of N-NE3TA labeled with 64Cu were stable and had high cellular uptake in HeLa and PC3 cancer cells. Tf-N-NE3TA was further conjugated with a fluorescence dye (Cy5.5) to develop targeted theranostic agent of cancer. Tf-N-NE3TA-Cy5.5 showed great radiolabeling efficiency with 64Cu, and the Tf-N-NE3TA-Cy5.5 labeled with 64Cu exhibited high cellular uptake in HeLa, HT29, and PC3 cancer cells. In summary, we have developed new bifunctional ligands having excellent chelation chemistry of 90Y, 177Lu, 205/6Bi, and 64Cu, and the tumor-specific antibody and peptide conjugates of the novel bifunctional chelators have a great potential for targeted cancer therapy and imaging as well as theranostic applications of cancer.
Ph.D. in Biology, July 2014
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Title: RELIABILITY AND ENERGY ANALYSIS FOR EXTREME SCALE SYSTEMS
Creator: Yu, Li
Date: 2015, 2015-12
Description: Reliability and energy are two of the top major concerns in the development of today's supercomputers. To build a powerful machine while at...
Show moreReliability and energy are two of the top major concerns in the development of today's supercomputers. To build a powerful machine while at the same time satisfying reliability requirement and energy constraint, HPC scientists continue to seek a better understanding of system and component behaviors. Toward this end, modern systems are deployed with various monitoring and logging tools to track reliability and energy data during system operations. Since these data contain important information about system reliability and energy, they are valuable resources for understanding system behaviors. However, as system scale and complexity continue to grow, the process of collecting system data to extracting meaningful knowledge out of overwhelming reliability and energy data faces a number of key challenges. To address these challenges, my work consists of three parts, including data preprocessing, data analysis and advanced modeling.
Ph.D. in Computer Science, December 2015
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Title: MULTIPLE SIGNAL TRANSDUCTION EVENTS AND MODULATION OF OLFACTORY RESPONSES IN MOUSE OLFACTORY SENSORY NEURONS
Creator: Yu, Yiqun
Date: 2012-04-30, 2012-07
Description: In the mammalian olfactory system, one olfactory sensory neuron (OSN) expresses a single olfactory receptor (OR) gene. I studied two subsets...
Show moreIn the mammalian olfactory system, one olfactory sensory neuron (OSN) expresses a single olfactory receptor (OR) gene. I studied two subsets of mouse OSNs, hereafter refered to as Ho-OSNs and AB-OSNs, in intact mouse olfactory turbinates using calcium imaging. Both of Ho-OSNs and AB-OSNs were located in the most ventral olfactory receptor zone. Ho-OSNs were specifically responsive to 2-heptanone (Ho), heptaldehyde (H) and cis-4-heptenal (cH). Dose-dependent analysis indicated that their responses to individual odorant was saturated within one logarithm unit of concentrations, a typical characteristic of isolated OSNs. Binary mixture and crossadpatation studies showed that these three odorants bound to the same binding sites in Ho-OSNs. However, these three structurally similar odorants activated distinct signaling pathways in Ho-OSNs. In detail, 2-heptanone-evoked intracellular calcium elevation was mediated by AC-cAMP signaling, while heptaldehyde triggered the PLC-DAG pathway. The cis-4-heptenal-evoked [Ca2+]i increases resulted from a combination of cAMP mediated activation and suppression involving PLC signaling. Furthermore, the PLCmediated intracellular calcium alteration was independent of IP3 signaling. A further complexity is that these olfactory receptors were able to interact with other types of Gprotein coupled receptors (GPCRs), such as purinergic receptors. I determined that both the P2X3 and P2Y2 receptor subtypes were expressed in Ho-OSNs. Application of purinergic agonists elevated [Ca2+]i increases in Ho-OSNs. It was discovered that the ATP-induced calcium response required either intracellular or extracellular calcium, while depletion of intracellular calcium stores blocked the UTP-evoked [Ca2+]i increases. Purinergic agonists were able to modulate the odor response in Ho-OSNs, and purinergic antagonist experiments showed that modulation of heptaldehyde-induced calcium responses was due to activation of P2X3 receptor subtypes while heptanone-induced calcium responses was not. Although AB-OSNs were found adjacent to Ho-OSNs, they had complete separate response profiles. AB-OSNs were sensitive to acetophenone (Ace) and benzaldehyde (Ben). In AB-OSNs, both acetophenone and benzaldehyde activated the PLC signaling pathway. Pharmacological characterization indicated that in AB-OSNs, P2X1 and P2Y2 receptors were present, which is different from that in Ho-OSNs. P2X and P2Y agonists modulated odorant responses in AB-OSNs. Purinergic signaling differentially regulated the various odorant responses in AB-OSNs. The acetophenoneevoked [Ca2+]i increases were negativly modulated through activation of the P2Y2 receptor, while the calcium response induced by benzaldehyde was modulated by P2X1 receptor activation. Collectively, these studies suggest that a complex signaling mechanism exists in OSNs, which has important implications for understanding the mechanism of information process in the olfactory system.
Ph.D. in Biology, July 2012
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Title: PAST- AND FUTURE- ORIENTED COGNITIONS IN PTSD: THE RELATIONSHIP BETWEEN RUMINATION AND WORRY IN DEPRESSION AND ANXIETY SYMPTOMS
Creator: Stickney, Laurie
Date: 2016, 2016-07
Description: Post-Traumatic Stress Disorder (PTSD) is a complex disorder characterized by symptoms of both anxiety and depression. Likewise, individuals...
Show morePost-Traumatic Stress Disorder (PTSD) is a complex disorder characterized by symptoms of both anxiety and depression. Likewise, individuals with PTSD experience Repetitive Negative Cognitions in the form of rumination and worry that may be focused on the past, present, or future. Although cognitions in individuals with PTSD have been studied, there is some question as to what types of cognitions individuals with PTSD generally experience and to what extent different types of cognitions contribute to different PTSD symptomatology. Further, although worry and rumination in PTSD have been studied, the question of the importance of the time-focus of cognitions in PTSD has not been adequately addressed. Time-focused cognitions and the relationships among depression, anxiety, rumination and worry were examined in this study using experience sampling method. Participants were asked to fill out a short survey measuring depression, anxiety, rumination, worry and time-focus five times per day for seven days. Results indicated that the presence of Current-focused cognitions strengthened the relationship between worry and anxiety compared to Future-focused cognitions. These findings suggest that in terms of the relationship between anxiety and worry, it is current-focus that is important not future-focus. Additionally, worry partially mediated the relationship between rumination and anxiety, and rumination partially mediated the relationship between worry and depression. Overall, the results suggest that time-focus may be important in some areas of PTSD, and the study highlights the complex relationships among depression, anxiety, rumination, worry and time-focused cognitions.
Ph.D. in Psychology, July 2016
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Title: INTERNET-BASED CONTACT PROGRAMS TO FIGHT THE STIGMA OF SCHIZOPHRENIA
Creator: Wassel, Abigail K.
Date: 2014, 2014-07
Description: Stigma is an insidious problem that has resulted in loss of opportunities for people with mental illness. Research suggests that contact...
Show moreStigma is an insidious problem that has resulted in loss of opportunities for people with mental illness. Research suggests that contact provided through a structured talk by a person with mental illness could serve as an effective tool in combating stigma and promoting attitude change. Additionally, research on imagined contact suggests this approach can also decrease negative stereotypes toward people with schizophrenia. The current study examined the effectiveness of these two approaches in changing attitudes toward people with mental illness when delivered via the Internet. It was hypothesized that both a videotaped contact and an imagined contact approach would increase positive attitudes and decrease negative attitudes toward people with mental illness when presented alone, and that efficacy would increase when combined. Findings showed no significant changes for any experimental condition from baseline attitudes or relative to a control condition, which suggests that interventions used in this study are not successful in creating sustainable attitude change over the Internet.
Ph.D. in Psychology, July 2014
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Title: A C-OMPARISON OF TWO ALGORITHMS FOR ADAPTING INTERVIEWS TO PERSONALITY SCORES
Creator: Van Overberghe, Courtney T.
Date: 2012-04-18, 2012-05
Description: Two adaptive interviews – adding questions based on low or high scores from a personality assessment – were compared to a structured interview...
Show moreTwo adaptive interviews – adding questions based on low or high scores from a personality assessment – were compared to a structured interview. In a mock selection process, it was found that the adaptive and structured interviews had similar correlations with performance on a role play task. However, due to the added length of the adaptive interview, it had slightly less utility than a structured interview. A cognitive measure and the interview conditions were better predictors of performance than the personality questionnaire, which had no relationship with performance. A post-hoc analysis found that the social desirable scale from the personality instrument correlated negatively with the structured interview, the role play and the IQ test, and positively correlated with the personality composite score.
Ph.D. in Psychology, May 2012
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Title: OPTIMAL DESIGN OF PERMANENT MAGNET SYNCHRONOUS MACHINES BASED ON MAGNETIC FIELD DISTRIBUTION ASSESSMENT AND PERFORMANCE ANALYSIS
Creator: Jiang, Yong
Date: 2015, 2015-05
Description: The detailed magnetic field distribution of a permanent magnet electric motor is very important for the accurate prediction of performance...
Show moreThe detailed magnetic field distribution of a permanent magnet electric motor is very important for the accurate prediction of performance parameters such as back electromotive force (back-EMF), rotor and stator losses, winding inductances, noise and vibration, torque profiles, etc. Although finite element analysis is a good option for accurately calculating magnetic field distribution in electrical machines, it is typically timeconsuming and does not provide closed form solutions. Alternatively, analytical calculation of magnetic field distribution can be conducted in Fourier series, which is more suitable for a design tool to predict the motor performance. This dissertation presents a novel numerical technique for calculating exact magnetic field distribution in the air gap of a surface mounted permanent magnet machine. This solution can be obtained via a two-dimension analytical solution with Laplacian and quasi-Poisonian equations, assuming that the iron is infinitely permeable and the air gap is slotless. Slot effects can be added in the model by using relative air gap permeance calculated by the conformal transformation of slot geometry. This technique is constructed by multiplying the relative permeance function expressed in an infinite Fourier series with the distribution of magnetic field in the slotless air gap. This method shows a very good alignment with finite element method for a surface mounted permanent magnet machine with radial magnetization. It can also be extended to calculating magnetic field distribution of interior permanent magnet motors including consideration of magnetic saturation, crosssaturation between d-axis and q-axes, affecting both inductances and flux linkages, as well as localized effects due to rotor bridges. Furthermore, this approach can be used to create a closed-form solution, which is the first step towards inverse modeling of electric machines. This is a complete paradigm shift in the design process for electric machines, which can reduce the time taken to design an electric machine, while reducing the active material content to make them power dense with significant reduction in cost. Furthermore, availability of analytical description of the field components will aid in the designer’s ability to distinguish between the control and magnetic design aspects.
Ph.D. in Electrical and Computer Engineering, May 2015
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Title: DEVELOPMENT OF NANOPARTICLE APPLICATIONS IN CELL IMAGING, BIOASSAY AND REACTIVE OXYGEN SPECIES DETECTION BASED ON SURFACE-ENHANCED RAMAN SPECTROSCOPY
Creator: Yiming, Huang
Date: 2011-08, 2011-07
Description: After mid-1970, the exploration of surface-enhanced Raman scattering (SERS) has been studied by many research groups. Compared to traditional...
Show moreAfter mid-1970, the exploration of surface-enhanced Raman scattering (SERS) has been studied by many research groups. Compared to traditional Raman spectroscopy, enormous cross section of molecules can be obtained in SERS by placing the molecules within the electromagnetic field present in metal surfaces. This enhancement is due to resonance between the optical field and surface plasmon of the metal substrate. Nanoshells which are composed of a silica core and a thin gold shell can greatly enhance Raman scattering without the need to pre-aggregate the particles, due to their tunable optical property. In our study, we synthesized nanoshells as our SERS substrates for Raman tags. The stability of nanoshells coated with three different self-assembled monolayers containing poly(ethylene glycol) (PEG) molecules has been studied. Probes with Raman active PEG molecules have been delivered and imaged in macrophage cells and MCF7 cells, based on SERS technique. The benefits of this imaging technique we developed here are: 1) it is faster; 2) it requires less preparation; 3) it can provide the information of nanoshells in a semi-quantitative way in vitro. We also developed a rapid and easy-to-execute half-sandwich bioassay for the detection of low volumes (< 2 μL) of antigens on nitrocellulose membrane, based on SERS. Multiple antibodies with MW from 18.2 kDa to 170 kDa were bioconjugated to polymers and grafted to nanoshell surface to detect antigens on the membrane. SERS-based biosensors were tagged with Raman active PEGs for recognition and quantification. Here, the bioassay showed great sensitivity to very low concentration x viii of antigens and multiplexed testing have been successfully conducted on different antigens simultaneously. Moreover, SERS-based novel reactive oxygen species (ROS) sensors were designed by establishing mixed-monolayer consisting of poly(ethylene) glycol thiol (PEGSH) and either 4-nitrobenzenethiol (4-NBT) or 4-mercaptophenol (4-MP) on the surface of nanoshells. By analyzing the changes in the molecular Raman spectrum, we were able to track the production of hydroxyl radicals in low concentrations (~ 10 μM). The sensors have been delivered into the cells and did not show significant oxidative stress to the cells. Therefore, these designed sensors are very promising for tracking ROS produced by cells when they are under oxidative stress.
Ph.D. in Chemistry, July 2011
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Title: THE MOLECULAR MECHANISM OF BAXΔ2-MEDIATED CELL DEATH AND ITS TISSUE DISTRIBUTION IN COLON CANCER
Creator: Zhang, Honghong
Date: 2014, 2014-07
Description: Bax is a pro-death tumor suppressor in the Bcl-2 family, and is frequently mutated in microsatellite instable tumors, especially Hereditary...
Show moreBax is a pro-death tumor suppressor in the Bcl-2 family, and is frequently mutated in microsatellite instable tumors, especially Hereditary Non-Polyposis Colorectal Cancer (HNPCC). The loss of apoptotic Bax contributes to tumor development and chemoresistance. We recently uncovered that the combination of a Bax microsatellite mutation with a specific alternative splicing generated a unique Bax isoform (BaxΔ2) in Bax-negative cells. Similar to the prototype Baxα, BaxΔ2 is a potent pro-apoptotic molecule. However, the pro-apoptotic mechanism, therapeutic implication, and tumor tissue distribution of BaxΔ2 protein remain elusive. In this thesis research, we isolated and analyzed isogenic sub-cell lines that represent different Bax microsatellite statuses from colorectal cancer cells. We found that the colon cancer cells harboring Bax microsatellite G7/G7 alleles produced low levels of endogenous BaxΔ2 transcripts and proteins. BaxΔ2-positive cells were selectively sensitive to a subgroup of chemotherapeutics in comparison with BaxΔ2-negative cells. Different from other Bax isoforms, which mostly act through targeting mitochondria, BaxΔ2 recruited caspase-8 into the aggregates for activation, and consequently induced cell death independent of the mitochondrial pathway. Furthermore, the distribution of BaxΔ2 protein was mostly found in well-differentiated epithelial cells in primary colon tumor tissues or in primary squamous buccal cells, which contain Bax G7 mutation. However, not all cells harboring the Bax G7 mutation had a detectable level of BaxΔ2 proteins. These data suggest that, similar to Baxα, BaxΔ2 protein is pro-apoptotic, but not toxic to normal cells; expression of BaxΔ2 protein restores apoptotic program in Bax negative cells via a non-classical signaling pathway. Importantly, BaxΔ2 may provide a selective chemotherapeutic advantage for certain Bax-negative colon tumors.
Ph.D. in Biology, July 2014
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Title: DEVELOPMENT OF COMPUTER-AIDED DIAGNOSIS METHODS IN MAMMOGRAPHY
Creator: Wang, Juan
Date: 2015, 2015-12
Description: Computer-aided diagnosis (CAD) is developed as a diagnostic aid to provide a “second opinion” in diagnosis of breast cancer in early stage....
Show moreComputer-aided diagnosis (CAD) is developed as a diagnostic aid to provide a “second opinion” in diagnosis of breast cancer in early stage. Clustered microcalcifications (MCs) can be an important early sign of breast cancer. The goal of this work is to develop automatic CAD methods in mammography for breast cancer. Its contribution consists of both development of machine learning algorithms and study of related issues in detection and diagnosis of breast cancer with clustered MCs. First, a bi-thresholding scheme is proposed for reduction of false-positives (FPs) associated with linear structures in MC detection. An unified classifier with dummy variable modeling is further developed to reduce the FPs caused by both linear structures and MC-like noise patterns. It is demonstrated that both of the proposed algorithms can reduce FPs in MC detection, and thus, improve the detection accuracy significantly. Second, a spatial density modeling approach is investigated to quantify the spatial distribution of the MCs in a cluster when the MC detection is inaccurate. A spatial density function (SDF) is defined such that the extracted features are more robust to the presence of FPs and false-negatives (FNs) in MC detection. The results show that the features extracted from the SDF can achieve better class separation while being robust to the variations in MC detection when compared with those extracted from a traditional region-based method. Third, a retrieval-boosted approach is studied to discriminate between the benign and malignant MC lesions. A retrieval strategy is proposed to boost the classification performance by taking into account the similarity both in image features and in pathology. An adaptive Adaboost classifier, which can be adapted to the retrieved cases at a low computational cost, is applied to demonstrate the benefit of the retrieval strategy. The results show that the retrieval-boosted approach can signifishow that the features extracted from the SDF can achieve better class separation while being robust to the variations in MC detection when compared with those extracted from a traditional region-based method. Third, a retrieval-boosted approach is studied to discriminate between the benign and malignant MC lesions. A retrieval strategy is proposed to boost the classification performance by taking into account the similarity both in image features and in pathology. An adaptive Adaboost classifier, which can be adapted to the retrieved cases at a low computational cost, is applied to demonstrate the benefit of the retrieval strategy. The results show that the retrieval-boosted approach can significantly outperform its baseline classifier and that inclusion of pathology information in the retrieval can further improve the classification accuracy. Fourth, the perceptual similarity of MC lesions by radiologists is studied. The issues investigated include the degree of variability in the similarity ratings, the impact of this variability on agreement between readers in retrieval of similar lesions, and the factors contributing to the readers’ similarity ratings. The results indicate that perceptually similar lesions could be of diagnostic value in diagnosis for clustered MCs. Fifth, the feasibility of modeling the perceptual similarity of MC lesions is investigated. A support vector regression (SVR) is applied to model the perceptual similarity of clustered MCs, and a feature saliency analysis derived from SVR is used to determine the most relevant image features among a large set of candidate features. The results demonstrate that the relevant features are consistent in radiologists’ similarity ratings among different MC lesions, indicating that the perceptual similarity of MC lesions by radiologists can be effectively modeled. Finally, whether retrieval of similar images can effectively assist radiologists in diagnosis of clustered MCs is investigated. A retrieval system for relevant images is designed by considering both perceptually similar image features and the likelihood of malignancy of the lesion under consideration. An observer study is conducted to evaluate the diagnostic value of the proposed retrieval system. The results indicate that the proposed retrieval system has the potential to improve the reader’s ability in diagnosis of breast cancer with clustered MCs.
Ph.D. in Electrical Engineering, December 2015
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Title: Quantitative Tools for Stochastic Dynamical Systems: Invariant Structures and Escape Probabilities
Creator: Kan, Xingye
Date: 2012-07-16, 2012-07
Description: Three types of quantitative structures, stochastic inertial manifolds, random invariant foliations, and escape probabilities, are investigated...
Show moreThree types of quantitative structures, stochastic inertial manifolds, random invariant foliations, and escape probabilities, are investigated to study stochastic dynamical systems. Invariant structures for stochastic dynamical systems are reviewed and detailed techniques for their simulation, approximation and construction are presented with several illustrative examples. First, a numerical approach for the simulation of inertial manifolds of stochastic evolutionary equations with multiplicative noise is presented and illustrated. After splitting the stochastic evolutionary equations into a backward and a forward part, a numerical scheme is devised for solving this backward-forward stochastic system, and an ensemble of graphs representing the inertial manifold is consequently obtained. This numerical approach is tested in two illustrative examples: one is for a stochastic differential equation and the other is for a stochastic partial differential equation. Second, invariant foliations for dynamical systems with small white noisy perturbation are approximated via asymptotic analysis. In other words, random invariant foliations are represented as a perturbation of the corresponding deterministic invariant foliations, with deviation errors estimated. The escape probability is a deterministic concept making methods of partial differential equations theory attainable to stochastic dynamics. Finally, the escape probability p(x) for dynamical systems driven by non-Gaussian L´evy motions, especially symmetric α-stable L´evy motions, is considered and characterized. More precisely, it is represented as the solution of the Balayage-Dirichlet problem of a certain partial differential-integral equation. This issue has been investigated previously for dynamical systems driven by Wiener process. Differences between escape probabilities for dynamical systems driven by Gaussian and non-Gaussian noises are highlighted.
Ph.D. in Applied Mathematics, July 2012
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