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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: 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: 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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Title: POWER PROFILING, ANALYSIS, LEARNING, AND MANAGEMENT FOR HIGH-PERFORMANCE COMPUTING
Creator: Wallace, Sean
Date: 2017, 2017-05
Description: As the field of supercomputing continues its relentless push towards greater speeds and higher levels of parallelism the power consumption of...
Show moreAs the field of supercomputing continues its relentless push towards greater speeds and higher levels of parallelism the power consumption of these large scale systems is steadily transitioning from a burden to a serious problem. While the machines are highly scaleable, the buildings, power supplies, etc. are not. Even the most power efficient systems today consume one to two megawatts per peata op/s. Multiplying that by 1,000 to reach the next generation of supercomputer (i.e., exascale) and the power necessary just to turn the machine on is simply impractical. Thus, power has become a primary design constraint for future supercomputing system designs. As such, it has become a matter of paramount importance to understand exactly how current generation systems utilize power and what implications this has on future systems. As the saying goes, you can't manage what you don't measure. This work addresses several large hurdles in fully understanding the power consumption of current systems and making actionable decisions based on this understanding. First, by leveraging environmental data collected from runs of real leadership class applications we analyze power consumption and temperature as it pertains to scale on a production IBM Blue Gene/Q supercomputer. Then, through development of a new power monitoring library, MonEQ, we quantitatively studied how power is consumed in major portions of the system (e.g., CPU, memory, etc.) through profiling of microbenchmarks. Expanding on this, we then studied how scale and network topology affect power consumption for several well-known benchmarks. Wanting to increase the effectiveness of our power monitoring library, we extended it to work with many of the most common classes of hardware available in today's HPC landscape. In doing so, we provided an in-depth analysis of what data is obtainable, what the process of obtaining it is like, and how data from different systems compares. Next, utilizing the knowledge gained from these experiences, we developed a new scheduling approach which utilizing power data can effectively keep a production system's power consumption under a user-specified power cap without modification to the applications running on the system. Finally, we extend this scheduling approach to be applicable to more than just one objective. In doing so, the scheduler can now optimize on multiple criteria instead of simply considering system utilization.
Ph.D. in Computer Science, May 2017
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Title: SEISMIC DESIGN STUDY OF STEEL PLATE SHEAR WALL
Creator: Moshiri, Ali
Date: 2012-04-20, 2012-05
Description: plate shear walls are an innovative lateral load-resisting system capable of effectively and economically bracing a building against both wind...
Show moreplate shear walls are an innovative lateral load-resisting system capable of effectively and economically bracing a building against both wind and earthquake forces. The system consists of infill steel plates connected to boundary beams and columns over the full height of the framed bay. Beam-to-column connections can be rigid or shear connections and the infill plates can be either stiffened or unstiffened, depending on the design philosophy of the infill plates. The view of some structural designers is to use heavy stiffeners to reinforce and increase the buckling capacity of shear walls, whereas, if the walls are left unstiffened and allowed to buckle, their energy absorption will increase significantly due to the post-buckling capacity. Performance of 9-story SPSW with moment resisting beam to column connections was studied under quasi-static loading condition and 10 earthquake records recorded in Los Angeles by developing a nonlinear dynamic explicit finite element models in ABAQUS. All the models were validated with experimental results. Effect of stiffness of boundary elements (VBE and HBE) and plate thickness on general behavior of the structure were also investigated. In design of SPSWs, vertical boundary elements play a major role in increasing the capacity of the system. In high seismic zones there is always a chance of plastic hinge formation in the boundary elements specially columns in any intermediate floor. It is recommended that SPSWs not be used for medium to high rise buildings in high seismic regions until the lack of capacity design requirements for this type of SPSW is rectified.
Ph.D. in Structural Engineering, May 2012
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Title: POLARIZATION INDUCED BY A TERAHERTZ ELECTRIC FIELD ON A CONDUCTIVE PARTICLE
Creator: Shen, Tao
Date: 2013, 2013-05
Description: Interactions of an electromagnetic wave with an object of dimensions small compared to the wavelength can often be accounted for by...
Show moreInteractions of an electromagnetic wave with an object of dimensions small compared to the wavelength can often be accounted for by considering the dipole moments, which are effective in explaining the scattering characteristics in the frequency range referred to as the Rayleigh region. Dielectric functions derived from polarization processes due to molecular orientation or bound charge displacements have been employed over the years to account for the scattering properties of particles. In the presence of mobile charges, bulk conductivity may be incorporated with a complex dielectric function to explain the peak in absorption near the plasma frequency exhibited by metallic particles in the optical region. With the current interest in nanostructures, an investigation of the electromagnetic properties of a conductive particle with attention given to space-charge effects would appear timely. This can be accomplished by coupling the transport equations of the charge carriers to the Maxwell’s equations. Results of computations performed for elementary structures such as plates and particles revealed the screening of the internal field while dispersion and absorptions effects are shown by the complex dipole moments. To gain insight into the nature of charge-wave interactions, results based on quasi-static formulation for the electric field will be compared with those based on full-wave analysis, with special attention given to the charge and current distributions within the structure. By consideration of the physical process of charge carrier motion and lattice polarization, the equivalent circuit model for a conductive nanoparticle in the terahertz frequency range is developed. All circuit elements are of electrical nature and can be directly expressed in terms of material parameters. The equivalent circuit can serve as the basis of analysis for composite structures and aggregates of which the conductive nanoparticle is a constituent.
PH.D in Electrical Engineering, May 2013
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Title: COMPUTATIONAL MODELS OF TRANSPARENT WATER STORAGE ENVELOPES FOR ENERGY EFFICIENT COMMERCIAL BUILDINGS
Creator: Liu, Xiangfeng
Date: 2012-04-25, 2012-05
Description: Transparent Water Storage Envelopes (TWSEs) are climatic adaptive fenestration systems. The major part of the system is an array of modular...
Show moreTransparent Water Storage Envelopes (TWSEs) are climatic adaptive fenestration systems. The major part of the system is an array of modular transparent water containers which are integrated into frames of curtain walls, and serve as both façade and auxiliary water tanks for a commercial building. The concept originates from the idea of combing transparency with dynamic benefits of thermal mass in summer, as well as passive solar heating in winter. Optical and thermal characteristics of TWSEs, including their energy performance, have been studied systematically via numerical approaches. Two numerical procedures covered in the thesis: one is based on the simplified synchronized onedimensional nodal thermal model, and the other is based on the more complex and accurate synchronized CFD model. In each numerical procedure, a triple-step simulation methodology and the correlated computational models of TWSEs are employed. Based on the calculation and simulation results, it can be definitely concluded that TWSEs are energy efficient fenestration systems. They can outperform conventional glazing as long as being designed elaborately with the consideration of the unique physical characteristics, applied under suitable climatic conditions, and operated with appropriate energy efficiency measures. Furthermore, the innovative technical paradigm of TWSEs and the numerical approach developed for energy simulation of TWSEs demonstrate great potential to be implemented in engineering practice for energy efficient commercial buildings.
Ph.D. in Architecture, May 2012
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Title: VERIFICATION OF LARGE-SCALE ON-CHIP POWER GRIDS
Creator: Xiong, Xuanxing
Date: 2013, 2013-05
Description: As technology scaling continues, the performance and reliability of integrated circuits become increasingly susceptible to power supply noises...
Show moreAs technology scaling continues, the performance and reliability of integrated circuits become increasingly susceptible to power supply noises, such as IR drops and Ldi/dt noises in the on-chip power grids. Reduced supply voltage levels in the grid can increase the gate delay, leading to timing violations and logic failures. In order to ensure a reliable chip design, it is critical to verify that the power grid is robust, i.e., the power supply noises are acceptable for all possible runtime situations. Hence, power grid verification has become an indispensable step in modern design flow of integrated circuits. Nowadays, it is common practice to verify power grids by simulation. Typically, an equivalent RC/RLC circuit model of the grid is extracted from the layout, and designers perform simulations to evaluate the power supply noises based on the current waveforms drawn by the circuit. As power grid simulation can only be performed after the circuit design is done, vectorless power grid verification has been introduced to enable early power grid verification with incomplete current specifications, so that the power grid design can be better tuned and optimized at early design stages, thus reducing the design time. Due to the increasing complexity of modern chips, power grid verification has become very challenging. The broad goal of this dissertation is to explore efficient algorithms for verifying large-scale on-chip power grids. Specifically, we study parallel power grid transient simulation, vectorless steady-state verification and vectorless transient verification. Parallel forward and back substitution algorithms are designed for efficient transient simulation; a set of novel algorithms are developed to incrementally improve the runtime efficiency of vectorless steady-state verification; and an efficient approach is proposed for vectorless transient verification with novel constraint setting.
PH.D in Electrical Engineering, May 2013
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Title: EXPLORING THE SHEAR-AND-TIME DEPENDENT DEGRADATION OF VON WILLEBRAND FACTOR UNDER VENTRICULAR ASSIST DEVICE-RELATED FLOW CONDITIONS
Creator: Yang, Shuo
Date: 2015, 2015-12
Description: Abnormalities in VWF can cause impaired blood coagulation which results in higher bleeding tendency in patients with this disorder. Alteration...
Show moreAbnormalities in VWF can cause impaired blood coagulation which results in higher bleeding tendency in patients with this disorder. Alteration in VWF is characteristic in ventricular assist devices (VADs) implanted subjects with failing hearts. The nature of the abnormalities produced and the conditions which produce such abnormalities are not fully understood. The studies in this thesis investigate quantitatively the effects of VADs and VAD-related flow conditions on VWF degradation. This thesis consists of three studies: 1) an in vitro VAD loop study in which was investigated the degradation effects of three VADs either under preclinical development (VAD I) or being commercially available (VAD II & III); 2) a viscometer shear study in which was investigated a variety of factors under the controlled condition of a modified Couette viscometer, namely, shear stress, exposure time, pulsatile frequency and protease function, with respect to VWF degradation 3) a tubular shear study in which was investigated the relative degradation effects of shear stress versus exposure time under more VAD-related shear stresses (10 - 100 times higher than physiological levels) and exposure times of miliseconds. In the VAD flow loop, significant VWF degradation induced by VADs wee observed with an approximately 95% loss of high molecular weight VWF by 60 minutes. In the viscometer and the tubular studies, the factors studied enhanced VWF degradation in the following manner: increased shear stress above physiological levels, prolonged exposure time and higher pulsatile shear frequency were associated with greater degradation; shear stress was a more dominant factor than exposure time with respect to the degradation; and a various shear stress regions demonstrated maximal degradation effects. In addition, calcium-dependent protease function was a necessity for VWF degradation at all shear stress levels investigated. The studies also revealed that the unfolding of VWF to expose the cleavage sites appeared to take more time under shear than the refolding to re-cover those sites under static conditions. Critical shear regions may be important for unfolding and degrading VWF multimers of various sizes.
Ph.D. in Biomedical Engineering, December 2015
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Title: TOPICS IN COUNTERPARTY RISK AND DYNAMIC CONIC FINANCE
Creator: Iyigunler, Ismail
Date: 2012-11-02, 2012-12
Description: This thesis consists of three essays about modeling counterparty risk and pricing derivative securities. In the rst essay, we analyze the...
Show moreThis thesis consists of three essays about modeling counterparty risk and pricing derivative securities. In the rst essay, we analyze the counterparty risk embedded in CDS contracts, in presence of a bilateral margin agreement. We focus on the pricing of collateralized counterparty risk, and we derive the bilateral Credit Valuation Adjustment (CVA), unilateral Credit Valuation Adjustment (UCVA), and Debt Valuation Adjustment (DVA). We propose a model for the collateral by incorporating all related factors such as the thresholds, haircuts and margin period of risk. We derive the dynamics of the bilateral CVA in a general form with related jump martingales. Counterparty risky and the counterparty risk-free spread dynamics are derived and the dynamics of the Spread Value Adjustment (SVA) is found as a consequence. We nally employ a Markovian copula model for default intensities and illustrate our ndings with numerical results. In the second essay we address the issue of computation of the bilateral CVA under rating triggers in presence of ratings-linked margin agreements. We consider collateralized OTC contracts, that are subject to rating triggers, between two parties { an investor and a counterparty. Moreover, we model the margin process as a function of the credit ratings of the counterparty and the investor. We employ a Markovian approach for modeling of the rating transitions and of the default probabilities of the counterparties. In this framework, we derive the representation for bilateral CVA. We also introduce a new component in the decomposition of the counterparty risky price: namely the rating valuation adjustment (RVA) that accounts for the rating triggers. We consider several dynamic collateralization schemes where the margin thresholds are linked to the credit ratings of the counterparties. We account for the rehypothecation risk in the presence of independent amounts. Our results are ix illustrated in terms of a CDS contract and an IRS contract. In the third essay, we study the problem of pricing in incomplete markets with risk measures and acceptability indices. We propose a model for nding the dynamic ask and bid prices of derivative securities using Dynamic Coherent Acceptability Indices (DCAI) in the presence of transaction costs. In this framework, we de ne and prove a representation theorem for dynamic bid ask prices. We show that our prices can be computed using dynamic Gain-Loss Ratio (dGLR), which is a DCAI. To illustrate our results, we provide several numerical examples, by pricing barrier options with dGLR.
PH.D in Applied Mathematics, December 2012
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Title: A METHODOLOGY FOR UTILIZATION OF DEGRADED WATER IN THERMOELECTRIC POWER PLANT COOLING SYSTEMS
Creator: Safari, Iman
Date: 2013, 2013-12
Description: The overall objective of this study was to develop a comprehensive methodology to identify viable treatment strategies for utilization of...
Show moreThe overall objective of this study was to develop a comprehensive methodology to identify viable treatment strategies for utilization of degraded waters for cooling in thermoelectric power systems. To achieve this objective a process simulation model was developed using Aspen Plus® with the OLI (OLI System, Inc.) water chemistry model to predict water quality and the rate of fouling in the recirculating cooling loop utilizing secondary-treated municipal wastewater (MWW) and tertiary-treated municipal wastewater as the sources of makeup water. This process simulation model includes sub- models for pre-treatment units; the cooling tower with water, CO2, and NH3 evaporation; as well as the recirculating cooling system and condenser with salt precipitation and fouling. The input parameters of the model, including CO2 mass transfer coefficients in the cooling tower and kinetics of salts precipitation reactions, were determined by developing mathematical models and calibrating the models with the experimental data obtained from literature. The process simulation module was used to predict the water quality in the recirculating cooling loop and the results were compared with pilot-scale experimental data from literature on makeup water alkalinity, loop pH and ammonia evaporation. The effects of various parameters including makeup water quality, salt formation, NH3 and CO2 evaporation mass transfer coefficients, heat load and operating temperatures were investigated. The results indicate that stripping of CO2 and NH3 in the cooling tower can significantly affect the cooling loop pH. x viii The model was also used to determine the rate of fouling in the condenser. The results indicate that the fouling rate of MWW as makeup water is significantly higher than that expected with fresh water, and tertiary treatment of MWW such as nitrification and/or softening can significantly reduce the fouling potential. Finally, the rate of fouling obtained from this study was integrated into the existing cost model developed earlier (at Illinois Institute of Technology) to perform the overall economic analysis. The results show that the use of municipal wastewater (MWW) to replace freshwater as makeup for the recirculating cooling loops of thermoelectric power plants is economically viable when tertiary treatments such as nitrification or softening are applied. Among various treatment strategies studied, nitrification of MWW has the lowest cost of 0.29 $/m3 for utilization in a 550 MW power plant. Furthermore, it was concluded that utilization of secondary treated municipal wastewater (MWW) without tertiary treatments such as nitrification or softening is not economically viable due to its significant fouling costs.
PH.D in Chemical Engineering, December 2013
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Title: CREDIT DEFAULT SWAP SPREAD FORECASTING USING THE LINEAR BAYESIAN RANDOM COEFFICIENTS MODEL WITH BALANCED PANELS
Creator: Arifi, Imir
Date: 2014, 2014-05
Description: This study (thesis) predicts out of sample one to five year quarterly credit default swap spread curves for subsets of a population comprised...
Show moreThis study (thesis) predicts out of sample one to five year quarterly credit default swap spread curves for subsets of a population comprised of 308 companies via the linear Bayesian Random Coefficient Model (RMC) with balanced panel construction, capturing over 80% of reference entities with liquid CDS term structures. The use of scoring, structural and reduced form model variations generates credit spread tenure points and curves at the company level. The Altman Z-score and classic Merton structural framework explain too little of the credit default swap spreads out of sample. However, The Merton structural framework works well in predicting out of sample credit default swap spreads when modified by deriving the implied leverage ratio via market spreads. The widely used, Bloomberg implemented, JPMorgan 2001(CDSW) model works well for the period the study covers. The Bayesian Random Coefficients model explains 87% of observed credit default swap spreads one quarter out of sample, substantially exceeding any published research on the credit spread forecasting subject.
PH.D in Management Science, May 2014
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Title: THE DEVELOPMENT OF AN INSTRUMENT TO EVALUATE TEACHERS’ CONCEPTS ABOUT NATURE OF MATHEMATICAL KNOWLEDGE
Creator: Kean, Lesa L.
Date: 2012-12-10, 2012-12
Description: While there does seem to be widespread consensus that teachers’ beliefs and concepts influence the way they teach, even the most recent...
Show moreWhile there does seem to be widespread consensus that teachers’ beliefs and concepts influence the way they teach, even the most recent international studies suggest that research-based evidence for this consensus is limited. In an effort to enlarge and enhance the pool of evidence that shows specific relationships between teacher beliefs and practice, the present author undertook to write an attitude survey and interview protocol that identifies and distinguishes teachers’ concepts on eight different aspects of NOMK. Such a survey seems to be a natural first step to providing evidence for the larger question of which beliefs correlate to what teacher behaviors. Eight NOMK aspects were identified and defined based on a review of over 68 resources including twelve that contained an existing assessment addressing NOMK concepts. While superficial inspection of the assessments referenced may suggest that the best solution may be to use an existing assessment or to compile a list of items from these various assessments and use that to assess NOMK, the researcher suggests four major issues that would suggest otherwise. The items of the assessment and the assessment as a whole were validated through several steps. First, the author started with over 40 survey items, distributed evenly over her eight aspects and including both Likert-type and open-ended items. Second, the items were randomized and distributed to practicing mathematics teachers for their feedback. Third, the items were revised and sent back out to teachers for additional feedback. Fourth, the resulting survey was piloted with over 20 community college teachers. Fifth, their responses were coded, and the open-ended items were coded by xii rubric and confirmed by a second coder. Sixth, the survey was revised once again and piloted to another sample of 20 with similar analysis. Finally, she conducted several forms of qualitative and quantitative analysis to cull down the items to those that produced the most valid and reliable survey items set possible. The resulting survey addresses six of the eight aspects proposed by the researcher and includes both Likert-type and open-ended items intended to be confirmed and clarified through interview. The researcher suggests further research be done in order to design items that validly and reliably identify teachers’ concepts of NOMK on the remaining two aspects.
PH.D in Mathematics Education, December 2012
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Title: SIMULATION AND DEVELOPMENT OF A CLINICAL ANALYZER-BASED IMAGING SYSTEM
Creator: Majidi, Keivan
Date: 2013, 2013-12
Description: The analyzer-based phase-sensitive X-ray imaging method (ABI) is emerging as a potential alternative to conventional radiography. ABI...
Show moreThe analyzer-based phase-sensitive X-ray imaging method (ABI) is emerging as a potential alternative to conventional radiography. ABI simultaneously generates a number of planar images containing information about scattering, refraction and absorption properties of the object. These parametric images are acquired by sampling the angular intensity profile (AIP) of an X-ray beam passing through the object at different positions of the analyzer crystal. Like many of the modern imaging techniques, ABI is a computed imaging method (meaning that the images are calculated from raw data). Therefore, the noise in ABI depends on the imaging conditions such as source flux, number of the analyzer positions, and the analyzer positions themselves as well as on the estimation method of the parameters. In the first part of this thesis, we use the Cramer-Rao lower bound to quantify the noise in ABI images and then investigate the effect of different analyzer-sampling strategies on this bound. The CRLB is the minimum bound for the variance of an unbiased estimator and defines the best noise performance that one can obtain regardless of which estimation method is used to estimate ABI parametric images. We will then use this bound to evaluate three ABI methods: Multiple-Image Radiography (MIR), Diffraction Enhanced Imaging (DEI) and Scatter Diffraction Enhanced Imaging (S-DEI). The proposed methodology can be used to evaluate any other ABI parametric image estimation technique. Synchrotron radiation has been the main source for experimental ABI and developing its methodologies, therefore the ABI application to clinical imaging has been very limited. It is inevitable to use conventional X-ray sources for ABI in order to utilize xii the technique in the clinical applications, however, due to the limited intensity of these sources and their finite source size, developing such systems is very challenging. In the second part of this thesis, we use computer simulations to understand the above challenges better. We measure the properties of this imaging system such as flux and point-spread function for various design parameters and discuss how to find an “optimal” setup based on these properties. The optimality of an imaging setup depends on the specific application that one wants to perform using the system; however, the results and discussions in this section layouts a design procedure for clinical ABI systems. In the last part of this thesis we review the steps we took in the Advanced X-ray Imaging Laboratory (AXIL) toward developing a clinical ABI system.
PH.D in Electrical Engineering, December 2013
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