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Title: COATING OF BORON NITRIDE THIN FILM ON TITANIUM
Creator: Huang, Mairui
Date: 2013, 2013-12
Description: To improve the wear resistance of titanium and extend its service life, coating boron nitride thin films on the surface of titanium matrix was...
Show moreTo improve the wear resistance of titanium and extend its service life, coating boron nitride thin films on the surface of titanium matrix was studied in this work. To obtain surface property enhancement, the samples were coated by isothermal sintering at 1000°C – 1400°C in a vacuum furnace for 2h, 4h or 6h. The microstructure of the thin film was investigated employing X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). To identify the composition of interlayers between BN and Ti, EDS analysis was run through the whole reaction zone. It showed that the BN was being consumed, titanium borides (TiB and TiB2), titanium nitride (TiN1-x), and solid solution of nitrogen in titanium (α-Ti (N)) layers formed at the interface between the BN coating and Ti matrix. Correspondingly, the XRD analysis indicated that TiB, TiB2, TiN, and α-Ti(N) phases were presented in good agreement with the EDS result. The layers grew fast in the sintering process which benefited from the fine grain size and highly oriented layers grown in the reaction zone. However, the well-known parabolic diffusional growth is only part of mechanisms for explaining the reactiondiffusion kinetics. The diffusion paths were obtained from the phase sequences at the interface between BN and Ti and thus could be represented on the isothermal section of the B-N-Ti ternary diagram. Moreover, the influence of the sintering temperature and the length of the actual sintering period on the layer sequences and thickness of the reaction zone were investigated. The micro-hardness test results showed that the Ti matrix with deposited BN thin films exhibited significant increased surface hardness. Obviously, the surface hardness xiii rose along with sintering temperature and holding time, and the hardness could be improved over 50%.
M.S. in Materials Science and Engineering, December 2013
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Title: SIMULATING THE HESTON MODEL VIA THE QE METHOD WITH A SPECIFIED ERROR TOLERANCE
Creator: Zhao, Xiaoyang
Date: 2017, 2017-05
Description: The Quadratic Exponential (QE) model is a market standard simulation method for the Heston stochastic volatility model. We identify certain...
Show moreThe Quadratic Exponential (QE) model is a market standard simulation method for the Heston stochastic volatility model. We identify certain numerical problems with the standard discretization and modify the original method to correct these problems. We implement our modified QE scheme for the Heston model in the Guaranteed Automatic Integration Library (GAIL)|a suite of algorithms that includes Monte Carlo and quasi-Monte Carlo methods for multidimensional integration and computation of means. GAIL computes answers to satisfy user-defined error tolerances. We also implement variance reduction techniques for our modified QE scheme in GAIL. The numerical results show that our modified scheme is fast and accurate, and satisfies the user-defined error tolerances.
M.S. in Applied Mathematics, May 2017
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Title: THE RELATIONSHIP BETWEEN WORK-FAMILY CONFLICT, SOCIAL SUPPORT AND PERFORMANCE AMONG HEALTHCARE MANAGERS
Creator: Hunt, Mary K.
Date: 2011-05-16, 2011-05
Description: As high performers are of great value in all organizations, understanding factors influencing their ability to maintain strong performance can...
Show moreAs high performers are of great value in all organizations, understanding factors influencing their ability to maintain strong performance can have useful implications for leaders. This study examines the relationship between employees’ performance, their stressors and coping approaches as defined by work-family conflict and perception and enactment of social support. Three hundred and twelve managers in a healthcare organization were categorized based on their performance in the year prior to the study. Results showed that high performers had higher satisfaction and use of supervisor support than moderate performers. The more satisfied managers were with support from their supervisor, coworkers, and friends, the less they reported work-family conflict. Satisfaction and use of support from friends influenced both work-to-family and family-to- work conflict.
M.S. in Psychology, May 2011
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Title: SEISMIC STRUCTURAL ANALYSIS USING INTERVAL GROUND MOTION
Creator: Venezia, Adam
Date: 2011-12-05, 2011-12
Description: Seismic analysis is a crucial procedure for the design of a structure subjected to ground motion. In conventional seismic analysis procedures,...
Show moreSeismic analysis is a crucial procedure for the design of a structure subjected to ground motion. In conventional seismic analysis procedures, a structure is subjected to a limited number of earthquake excitations. Moreover, these procedures do not consider the presence of variations and uncertainties in those excitations. Interval analysis is one method capable of accounting for both of these limitations. In this work, a new method for seismic structural analysis, with interval uncertainty in the response spectrum, is developed, which is capable of obtaining the bounds of the dynamic response of a structure. This method is hereinafter referred to as Interval Ground Motion Analysis (IGMA). In this method, first, various response spectra are combined as an interval function, referred to as an interval response spectrum. Then, the response spectrum analysis is performed using the developed interval response spectrum, and the bounds of the dynamic response of the structure are obtained. It is shown that obtaining these bounds is computationally feasible and does not require iterative procedures such as Monte Carlo simulation. Numerical example problems, which illustrate the developed algorithm, are presented, along with a comparison of solutions obtained by another solution method.
M.S. in Civil Engineering, December 2011
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Title: CONGESTION CONTROL AND PACKET REORDERING FOR MULTIPATH TRANSMISSION CONTROL PROTOCOL
Creator: Ghose, Nirnimesh
Date: 2012-04-20, 2012-05
Description: Modern devices are equipped with multiple network interfaces. Traditionally, only one of these is in use at any given time. However,...
Show moreModern devices are equipped with multiple network interfaces. Traditionally, only one of these is in use at any given time. However, simultaneous use of these mul- tiple interfaces will lead to better user experience. Support for this multi-interface scenario has led to the development of Multipath Transmission Control Protocol or MPTCP. MPTCP, as proposed by the IETF working group mptcp, allows a single data stream to be split across multiple paths. This has obvious benefits for reliability, and it can also lead to more efficient use of network resources. But a major problem in MPTCP is the congestion control and the eventual packet reordering at the desti- nation. Various techniques for congestion control for MPTCP have been given, but the packet reordering at the destination is not considered. Efficient packet reordering schemes can drastically improve the throughput for the MPTCP protocol. Therefore, in this work various available packet reordering techniques available for single path TCP are tested in the multipath situation. These algorithms are Duplicate Selective Acknowledgement (DSACK), Eifel and Forward Retransmission Timeout (F RTO). Various network topologies are simulated in a network simulator ns-3 and measure- ments are taken for various path characteristics to see which algorithm works best for the multipath scenario.
M.S. in Electrical Engineering, May 2012
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Title: Control of complex distributed systems with distributed intelligent agents
Creator: Tatara, Eric, Cinar, Ali, Teymour, Fouad
Date: 2007-06
Publisher: ELSEVIER SCI LTD
Description: Control of spatially distributed systems is a challenging problem because of their complex nature, nonlinearity, and generally high order. The...
Show moreControl of spatially distributed systems is a challenging problem because of their complex nature, nonlinearity, and generally high order. The lack of accurate and computationally efficient model-based techniques for large, spatially distributed systems leads to challenges in controlling the system. Agent-based control structures provide a powerful tool to manago distributed systems by utilizing (organizing) local and global information obtained from the system. A hierarchical, agent-based system with local and global controller agents is developed to control networks of interconnected chemical reactors (CSTRs). The global controller agent dynamically updates local controller agent's objectives as the reactor network conditions change. One challenge posed is control of the spatial distribution of autocatalytic species in a network of reactors hosting multiple species. The multi-agent control system is able to intelligently manipulate the network flow rates such that the desired spatial distribution of species is achieved. Furthermore, the robustness and flexibility of the agent-based control system is illustrated through examples of disturbance rejection and scalability with respect to the size of the network.
Endnote format citation for DOI:10.1016/j.jprocont.2006.06.008
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Title: A PARAMETRIC STUDY OF THE THERMAL PERFORMANCE OF DIFFERENT WALL SYSTEMS AT VARIOUS CLIMATE ZONES
Creator: Lai, Se Yen
Date: 2013, 2013-12
Description: One of the most common energy conservative measures used is designing an air-tight and a well-insulated envelope. While there is an abundance...
Show moreOne of the most common energy conservative measures used is designing an air-tight and a well-insulated envelope. While there is an abundance of high-efficiency building envelope designs in the market which offer low thermal conductivity and high R-values as well as various studies on the thermal performance of various wall constructions, the results were often based on simplified study model and are not incompliance with the current building code. Most studies also focus on only one particular climate zone and one type of wall construction. This research aims to examine the thermal performance of different types of wall construction based on the traditional building envelope design materials in various climate zones based on insulation and air cavity placements on a non-simplified reference model that is used for construction. Study models developed are incompliance with the American Society of Heating, Refrigerating, and Air-Conditioning Engineers [ASHRAE] 90.1-2010 based on U.S. Department of Energy [DOE] Commercial Prototype Building Model. The thermal performance of the wall will be determined using two different methods. The first method will be using Building Energy Modeling [BEM] software where the exterior wall construction will be modified based on DOE reference models where the results for the overall annual energy consumption [AEC] will be compared. AEC results showed small differences between study models which are negligible. The second method is the Total Thermal Constant [TTC] method, where the thermal lag will be compared. The building structures that will be used are a steel-framed structure which represents a medium office and a wood-framed structure which represents a quick service restaurant. TTC results were able to determine the least favorable study model.
M.S. in Civil Engineering, December 2013
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Title: Online batch/fed-batch process performance monitoring, quality prediction, and variable-contribution analysis for diagnosis
Creator: Undey, C., Ertunc, S., Cinar, A.
Date: 2003-10-01
Publisher: AMER CHEMICAL SOC
Description: An integrated online multivariate statistical process monitoring (MSPM), quality prediction, and fault diagnosis framework is developed for...
Show moreAn integrated online multivariate statistical process monitoring (MSPM), quality prediction, and fault diagnosis framework is developed for batch processes. Batch data from I batches, with J process variables measured at K time points generate a three-way array of size I x K x J. Unfolding this three-way array into a two-way matrix of size IK x J by preserving the variable direction is advantageous for developing online MSPM methods because it does not require estimation of future portions of new batches. Two different multiway partial least squares (MPLS) models are developed. The first model (MPLSV) is developed between the data matrix (IK x J) and the local batch time (or an indicator variable) for online MSPM. The second model (MPLSB) is developed between the rearranged data matrix in the batch direction (I x KJ) and the final quality matrix for online prediction of end-of-batch quality. The problem of discontinuity in process variable measurements due to operation switching (or moving to a different phase) that causes problems in alignment and modeling is addressed. Control limits on variable contribution plots are used to improve fault diagnosis capabilities of the MSPM framework. Case studies from a simulated fed-batch penicillin fermentation illustrate the implementation of the methodology.
Endnote format citation for DOI:10.1021/ie0208218
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Title: A UNIFIED BOUNDARY CONTROL LAW FOR DC-DC CONVERTERS USING A NORMALIZED STATE PLANE
Creator: Nie, Yue
Date: 2015, 2015-05
Description: This thesis proposes a unified boundary control law for DC-DC converters (Buck, Boost, and Buck-Boost) which improves both the transient and...
Show moreThis thesis proposes a unified boundary control law for DC-DC converters (Buck, Boost, and Buck-Boost) which improves both the transient and steady state response in comparison to boundary control laws using first or second order switching surface. A new set of switching zones on normalized state plane are defined to decide switching behavior every sample period. Additionally, non-ideal operations and a parameter self-adaptive algorithm are proposed and verified in simulation. The parameter self-adaptive algorithm enhances the system robustness and reduces the parameter sensitivity. The transient bandwidth for the load disturbance rejection and command tracking approaches the physical limits of DC-DC converters. Simulation results are presented to illustrate the major benefits of the proposed uni ed boundary control law.
M.S. in Electrical Engineering, May 2015
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Title: Boosted heavy particles and jet substructure with the CMS detector, Proceedings of the XLIII International Symposium on Multiparticle Dynamics
Creator: Marchesini, Ivan
Date: 2013-09-15, 2013-09-15
Publisher: IIT Press
Description: In the last years, the understanding of jets and jet substructure has become increasingly important, in particular in the context of new...
Show moreIn the last years, the understanding of jets and jet substructure has become increasingly important, in particular in the context of new physics searches. Many new physics models involve highly boosted hadronically-decaying particles, which result in jet-like objects with large masses and an intrinsic substructure. Discrimination of these heavy jets from ordinary quark and gluon jets is possible through a plethora of new techniques. The understanding of jets can be exploited also for the identification of pileup jets and for the discrimination between quark jets and gluon jets. A sampling of these techniques is discussed together with their validation on collider data recorded in proton-proton collisions at √s = 8TeV with the CMS detector in the year 2012. The commissioning in the boosted regime of algorithms used to identify jets originating from bottom quarks is also discussed. Many studies have highlighted the potential of using jet substructure techniques to improve the sensitivity in physics searches. An overview of recent CMS results employing these techniques is presented.
Sponsorship: IIT College of Science, High Energy Physics Division of Argonne National Laboratory
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Title: SUBSTATION PLANNING FOR RURAL DISTRIBUTION SYSTEMS IN AFRICAN COUNTRIES
Creator: Soyoye, Oluwadamilola
Date: 2016, 2016-12
Description: In sub-Saharan Africa, only 35% of the population is connected to grid electricity [2]. Grid-connected parts face serious transmission and...
Show moreIn sub-Saharan Africa, only 35% of the population is connected to grid electricity [2]. Grid-connected parts face serious transmission and distribution challenges. There is also the challenge of electricity demand being greater than electricity supply. These issues in all levels of the traditional power system – generation, transmission and distribution have led to gross inadequacy of electricity supply. This research focuses on the capital intensive Power Distribution Planning (PDP). Most problems in the distribution system affect the consumer directly. Distribution substation planning, a critical part of the PDP, particularly addresses the issue of overloaded distribution systems. It is not uncommon for substation transformers in some African communities to become damaged because of overloading. The choice of location, sizing, siting and number of substations is determined by considering load distribution, feeder lengths and sizes, and the interruption costs. The research illustrates a framework for substation planning, incorporating possible future load growths over a particular period to forestall unwanted failures in the distribution system. A direct algorithm is used, where the substation capacity is computed manually from the load levels at different points. This algorithm is later combined with the Mixed Integer Linear Programming (MILP) approach solved with the CPLEX solver in MATLAB.
M.S. in Electrical Engineering, December 2016
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Title: High Speed Jet Flows, 1995: Presented at the 1995 ASME/JSME Fluids Engineering and Laser Anemometry Conference and Exhibition, August 13-18, 1995, Hilton Head, South Carolina
Creator: Raman, Ganesh, Kaji, S., Freitas, Christopher J.
Date: 1995
Publisher: American Society of Mechanical Engineers

Title: Tests on enameled wire
Creator: Gault, Mark E.
Date: 2009, 1911
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/testsonenameledw00gaul
Thesis (B.S.)--Armour Institute of Technology; Bibliography: leaf 26

Title: MINIMIZING SALMONELLA CONTAMINATION IN SPROUTS BY CONTROLLING THE GERMINATION TEMPERATURE
Creator: Zhang, Hanshuai
Date: 2013, 2013-12
Description: Since 1990, contaminated sprouts have been linked to at least 46 outbreaks and over 2,500 cases of illness in the US [13]. Unlike other ready...
Show moreSince 1990, contaminated sprouts have been linked to at least 46 outbreaks and over 2,500 cases of illness in the US [13]. Unlike other ready-to-eat produce, sprouts pose a particular concern as the conditions that promote germination of their seeds also facilitate the growth of pathogens [6]. To address sprout’s propensity to microbial contamination, the U.S. Food and Drug Administration (FDA) has recommended that seeds destined for sprout production be disinfected with chemical sanitizers such as 20,000 ppm of calcium hypochlorite, Ca(OCl)2 [29]. However, this disinfectant often cannot completely eliminate pathogen that may be present in seeds [4, 23]; in which case, the surviving bacteria can re-grow to significant numbers during germination and cause severe illness upon consumption [45]. Therefore, maintaining control of the germination conditions to present the proliferation of pathogens is a crucial step in the overall approach to reduce microbial hazards in finished sprouts. This study examines the effects of temperature on the proliferation of Salmonella during germination, and how this temperature effect is influenced by factors such as pathogen load, seed-lot, and the presence or absence of chemical treatment with Ca(OCl)2 was also evaluated. Alfalfa seeds artificially inoculated with ~3 log CFU/g of Salmonella were used as the contaminated seeds. They were mixed at different levels (0.01, 0.1, 1.0, or 10.0% by weight) with 200g of non-contaminated seeds and then were allowed to germinate in glass jars for 3 or 5 days at 10, 20, or 30°C. The same experiment was repeated for the spiking seeds that were treated with 20,000 ppm Ca(ClO)2 for 15 min prior to sprouting. Sprout samples were taken from each jar daily and analyzed for the level of Salmonella ix by either plating on XLD plates or the three-tube most probable number method as described in the FDA BAM. The level of Salmonella increased during sprouting at all three temperatures and reached the highest level at 48h. Sprouting at 10°C yielded the least number of Salmonella when all other factors were controlled. At all spiking levels, or the percentage of seeds contaminated before sprouting, level of Salmonella increased during sprouting, and at 20°C and 30°C, the level of Salmonella reached to a similar level of 5 log CFU/g and 7 log CFU/g respectively. At 1.0% spiking level, the level of Salmonella increased by approximately 1.5, 4.0, and 6.0 log CFU/g in sprouts grown at 10, 20, and 30°C respectively. Difference in the level of microflora background between different seed lots did not appear to affect Salmonella proliferation during sprouting. Treatments with 20,000 ppm free chlorine in some cases lowered the levels of Salmonella to undetectable levels, while in other cases, it caused an approx. 3 log reduction in Salmonella count on seeds. The surviving ones could still proliferate during sprouting although with a delay and a much slower rate, and did not reach the maximal level at 48 h of sprouting. However, Ca(OCl)2 did not prevent the re-growth of Salmonella during germination. In conclusion, these results showed that sprouting temperatures do affect Salmonella proliferations. We recommend lowering the sprouting temperature in conjunction with chemical treatment of prior to sprouting seeds to reduce microbial hazards in sprouts.
M.S. in Food Safety and Technology, December 2013
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Title: LARGE-SCALE SIMULATION OF ELECTRIC POWER SYSTEMS FOR WIND
Creator: Wei, Tian
Date: 2011-08, 2011-07
Description: The utilization of wind energy will pose great socioeconomic benefits with reductions in power plant emissions and the supply of zero cost...
Show moreThe utilization of wind energy will pose great socioeconomic benefits with reductions in power plant emissions and the supply of zero cost energy; however, largescale wind energy integration could introduce inevitable challenges to regional transmission systems and hourly system operations. This thesis addresses the congestion identification, simulation and analysis of large-scale electric power systems in different scenarios, large-scale wind energy integration and related transmission expansion issues. A methodology based on the security-constrained unit commitment (SCUC) is applied to analyze the transmission congestions in the Eastern Interconnection of the United States. The identified congestions are visualized along with the Geographical Information System (GIS) data and compared with the results in National Electric Transmission Congestion Study (NETCS) published by the Department of Energy of the United States in 2006. The study also provides the locational marginal price (LMP) information in the Eastern Interconnection, which is not available in the NETCS report. This thesis implements a comprehensive simulation and scenario analysis of the Illinois electric power system for the year 2011. Possible scenarios representing electrical load sensitivities to economic growth, fuel price variations, and the impact of carbon cost, are studied. This thesis presents the hourly simulation results for the large-scale wind energy integration in the Eastern Interconnection of the United States. An hourly unit commitment is applied for the simulation of the economics of wind energy integration in the year 2030. The energy portfolio for supplying the hourly load in 2030 is developed based on wind integration levels. The sensitivities of fuel price, wind energy quantity, xvii load forecast, carbon cost, and load management to the proposed 2030 wind integration are studied. This thesis identifies transmission congestions and expands the existing transmission system in the Eastern Interconnection of the United States for accommodating a large-scale integration of wind energy. Violated transmission flows which would cause the infeasibility of hourly SCUC are identified. An iterative transmission expansion analysis is implemented to identify the minimum required additions to the Eastern Interconnection for mitigating hourly transmission congestions.
Ph.D. in Electrical Engineering, July 2011
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Title: DIRECT DIFFEOMORPHIC REPARAMETERIZATION FOR CORRESPONDENCE OPTIMIZATION IN STATISTICAL SHAPE MODELING
Creator: Li, Kang
Date: 2015, 2015-05
Description: This dissertation proposes an efficient optimization approach for obtaining shape correspondence across a group of objects for statistical...
Show moreThis dissertation proposes an efficient optimization approach for obtaining shape correspondence across a group of objects for statistical shape modeling. With each shape represented in a B-spline based parametric form, the correspondence across the shape population is cast as an issue of seeking a reparametrization for each shape so that a quality measure of the resulting shape correspondence across the group is optimized. The quality measure is the description length of covariance matrix of the shape population, with landmarks sampled on each shape. The movement of landmarks on each B-spline shape is controlled by the reparameterization of the B-spline shape. The reparameterization itself is also represented with B-splines and B-spline coefficients are used as optimization parameters. We have developed formulations for ensuring the bijectivity of the reparameterization. A gradient-based optimization approach is developed, including techniques such as constraint aggregation and adjoint senstivity for efficient, direct di↵eomorphic reparameterization of landmarks to improve the group-wise shape correspondence. Numerical experiments on both synthetic and real 2D and 3D data sets demonstrate the efficiency and e↵ectiveness of the proposed approach.This dissertation proposes an efficient optimization approach for obtaining shape correspondence across a group of objects for statistical shape modeling. With each shape represented in a B-spline based parametric form, the correspondence across the shape population is cast as an issue of seeking a reparametrization for each shape so that a quality measure of the resulting shape correspondence across the group is optimized. The quality measure is the description length of covariance matrix of the shape population, with landmarks sampled on each shape. The movement of landmarks on each B-spline shape is controlled by the reparameterization of the B-spline shape. The reparameterization itself is also represented with B-splines and B-spline coefficients are used as optimization parameters. We have developed formulations for ensuring the bijectivity of the reparameterization. A gradient-based optimization approach is developed, including techniques such as constraint aggregation and adjoint senstivity for efficient, direct di↵eomorphic reparameterization of landmarks to improve the group-wise shape correspondence. Numerical experiments on both synthetic and real 2D and 3D data sets demonstrate the efficiency and e↵ectiveness of the proposed approach.
Ph.D. in Mechanical and Aerospace Engineering, May 2015
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Title: Estimation of Future Glucose Concentrations with Subject-Specific Recursive Linear Models
Creator: Eren-oruklu, Meriyan, Cinar, Ali, Quinn, Lauretta, Smith, Donald
Date: 2009-04
Publisher: MARY ANN LIEBERT INC
Description: Background: Estimation of future glucose concentrations is a crucial task for diabetes management. Predicted glucose values can be used for...
Show moreBackground: Estimation of future glucose concentrations is a crucial task for diabetes management. Predicted glucose values can be used for early hypoglycemic/hyperglycemic alarms or for adjustment of insulin injections or insulin infusion rates of manual or automated pumps. Continuous glucose monitoring (CGM) technologies provide glucose readings at a high frequency and consequently detailed insight into the subject's glucose variations. The objective of this research is to develop reliable subject-specific glucose prediction models using CGM data. Methods: Two separate patient databases collected under hospitalized (disturbance-free) and normal daily life conditions are used for validation of the proposed glucose prediction algorithm. Both databases consist of glucose concentration data collected at 5-min intervals using a CGM device. Using time-series analysis, low-order linear models are developed from patients' own CGM data. The time-series models are integrated with recursive identification and change detection methods, which enables dynamic adaptation of the model to inter-/intra-subject variability and glycemic disturbances. Prediction performance is evaluated in terms of glucose prediction error and Clarke Error Grid analysis (CG-EGA). Results: Prediction errors are significantly reduced with recursive identification of the models, and predictions are further improved with inclusion of a parameter change detection method. CG-EGA analysis results in accurate readings of 90% or more. Conclusions: Subject-specific glucose prediction strategy has been developed. Including a change detection method to the recursive algorithm improves the prediction accuracy. The proposed modeling algorithm with small number of parameters is a good candidate for installation in portable devices for early hypoglycemic/hyperglycemic alarms and for closing the glucose regulation loop with an insulin pump.
Endnote format citation
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Title: THE RELATIONSHIPS OF BIOLOGICAL, PSYCHOLOGICAL, AND SOCIAL FACTORS TO PERCEIVED SEIZURE SEVERITY IN INDIVIDUALS WITH TEMPORAL LOBE EPILEPSY
Creator: Fong, Wing Man
Date: 2012-12-17, 2012-12
Description: Epilepsy is a chronic neurological condition that can cause negative consequences in all areas of life for people with the condition. Research...
Show moreEpilepsy is a chronic neurological condition that can cause negative consequences in all areas of life for people with the condition. Research evidence has led to the goal of treatment to gradually shift from targeting only reducing the frequency of seizures to decreasing individual’s perception of seizure severity. While several studies have suggested that psychological and social factors, in addition to epilepsy-related biological factors, can also impact seizure severity perception, this area has received much less attention in relation to individuals’ perception of seizure severity. Therefore, this study examined individuals’ perception of seizure severity using a biopsychosocial framework which takes into account biological, psychological, and social factors to develop a comprehensive understanding about the perception of seizure severity. 57 individuals from a neurology clinic at a tertiary medical center with a primary diagnosis of localization-related temporal lobe epilepsy participated in this study. They were interviewed for demographic information and were assessed using Quality of Life in Epilepsy-89, Beck Depression Inventory, Stressful Life Events Scale, and Liverpool Seizure Severity Scale. A Multiple regression analysis indicated that the number of antiepileptic drugs, perceived memory function, the number of stressful life events, and social support were all significant predictors of perceived seizure severity. The current findings supported a biopsychosocial approach in understanding the perception of seizure severity among people with epilepsy. Clinical implications of these findings are discussed.
M.S. in Psychology, December 2012
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Title: DEPTH MAP PROCESSING FOR MULTI-VIEW VIDEO PLUS DEPTH
Creator: Vijayanagar, Krisha Rao
Date: 2014, 2014-05
Description: The world of multimedia and visual entertainment has grown in leaps and bounds in the past decade with 3-D television being one of the biggest...
Show moreThe world of multimedia and visual entertainment has grown in leaps and bounds in the past decade with 3-D television being one of the biggest technologies. Amongst several formats proposed for representing 3-D content, multi- view video plus depth (MVD) format has gained a lot of interest in the past few years. MVD requires that each view of a particular scene be accompanied by a per-pixel depth. This introduces new problems for compression and transmission of MVD content because a depth map has di erent characteristics from a color image. Keeping the MVD format and depth map characteristics in mind, we highlight three majors problems that plague the MVD format, namely, 1. depth map re nement. 2. depth map compression. 3. novel view synthesis using the depth map at the decoder side. In order to re ne a depth map, we propose a multi-resolution anisotropic di usion algorithm that is optimized to run in real-time thus ensuring that the encoder does not su er from additional latency. Next, we propose two unique solutions for compressing them. We rst propose a solution using the Layered Depth Video (LDV) concept using a rate-distortion optimized quadtree decomposition of the LDV using a novel two-mode block truncation code with improved prediction. We also propose a compression solution using compressive sensing (CS) concepts by creating a hybrid rate-optimized CS codec. This codec achieves two goals:- rstly, block classi cation to ensure lower decoder complexity and secondly, rate-distortion optimization of the measurement rate for each block that is to be compressively sensed. We then look at the view synthesis component of the MVD tool-chain which x is a time-sensitive process. Keeping decoding latency in mind, we propose a lookup- table based approach to the 3-D warping process with a simpli ed hole- lling algorithm that is not only competitive quality-wise with other schemes but is several times faster too. It is hopeful that the presented techniques can be used successfully to create MVD architectures for applications that need low-complexity encoding solutions.
PH.D in Electrical Engineering, May 2014
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Title: COMPUTER MODELING OF BREAST LESIONS AND STUDIES OF ANALYZER-BASED X-RAY IMAGING
Creator: Garcia, Luis De Sisternes
Date: 2011-11, 2011-12
Description: Phase-contrast x-ray imaging is an emerging technique that promises to yield highly sensitive medical images of soft tissue, which is...
Show morePhase-contrast x-ray imaging is an emerging technique that promises to yield highly sensitive medical images of soft tissue, which is difficult to observe via conventional radiography given its low X-ray attenuation differences. One of these phase-contrast techniques, known as analyzer-based imaging, has demonstrated that highly detailed breast tissue images can be obtained using synchrotron radiation. However, synchrotron facilities are impractical for clinical use. This thesis introduces studies and exposure consideration towards the application of analyzer-based imaging in a clinical environment, particularly in the context of breast imaging. It also introduces a computational breast lesion model that generates randomized three-dimensional phantoms which follow realistically the characteristics observed in real lesions. Moving analyzer-based imaging to clinical application requires the consideration of photon noise, inherent from the use of a photon-limited conventional source. We summarize the statistical properties in the presence of photon noise of two popular analyzer-based imaging techniques, known as diffraction-enhanced imaging (DEI) and multiple-image radiography (MIR). The statistics for MIR have not been previously derived and are introduced in this thesis. Comparison of the resulting statistical predictions with results obtained by Monte Carlo simulation validated the analysis. An expression for the maximum-likelihood (ML) solution for analyzer-based imaging is presented as a way of minimizing the effects of photon noise in the reconstruction of the object’s absorption, refraction and ultra-small angle scattering properties, and more practical maximum-likelihood expectation-maximization (ML-EM) and maximum-a-posteriori expectation-maximization (MAP-EM) solutions are also introduced. The behavior of the ML-EM and MAP-EM solutions was compared to the results produced by the five best-known analyzer-based reconstruction methods using computer simulations. The ML-EM and MAP-EM reconstructions proved closer to the theoretical values as they do not rely on commonly known limitations and approximations introduced by the other techniques. We introduce the development and evaluation of a new computational breast lesion phantom model that can simulate either massess or microcalcifications. The proposed tool allows the generation of a large number of randomized three-dimensional breast lesion simulations following desired characteristics normally used to describe breast lesions in clinical practice. The initial motivation for the development of this new phantom model was to enable the proposed evaluations of analyzer-based imaging to be achieved. However, the model became a major focus of this thesis because it improves significantly upon those that can be found in previous literature. The proposed lesion model can be used for evaluation studies across different breast imaging techniques, as well as for training purposes, so it is our hope that it could become an important resource for the broader mammography research community. As part of the lesion modeling research, we also introduce methods to computationally modify experimental mammography and analyzer-based images of breast tissue so that they present the generated tumor simulations embedded within their parenchyma realistically. The realism of the simulated lesion images was evaluated by comparison of 83 real tumor cases observed in mammograms with 83 constructed hybrid images in which simulated tumors matching the characteristics observed in the real cases were embedded, with healthy tissue acting as background. As a quantitative comparison, extracted features describing tumor shape and density showed no statistically significant differences between real and simulated tumors. A known computational tumor classification technique based on their shape observed in mammography was implemented and showed no significant performance differences between real and simulated cases, as well as showing good correlation with previously published performance results in real tumors. To measure the realism for use in human observer studies, we conducted a reader study in which 5 experienced radiologists were asked to judge whether each of the 166 images was real or simulated by assigning a score on a 7-point scale. The results were analyzed in a multiple-reader multiple-case statistical framework. The conclusion of the study was that the readers’ accuracy in assessing whether the lesions were real or simulated was not significantly better than random chance. This thesis also incorporates a reader study to evaluate the degree to which photon-limited analyzer-based images may be effective for visualization of breast cancer features. Our motivation was to establish the x-ray intensity that would be required to make these methods feasible, the purpose being to serve as a guide in parameter selection for future design of imaging hardware. We conducted a series of observer studies that quantify the performance of analyzer-based refraction images at different noise levels for the task of identifying subtle details present in breast tumors which are relevant to clinical diagnosis. The cases shown to the readers consisted of hybrid images where simulated lesions of known characteristics were computationally embedded in real breast analyzer-based background images. The original phase-contrast data was obtained using synchrotron radiation and was later modified to simulate the noise and blurring effects produced from a photon-limited source with a 300μm aperture size, similar to those used in a laboratory environment. Results showed that the analyzer-based imaging techniques statistically outperformed conventional mammography for the given task with an average of just 128 recorded photons per pixel in background image regions
Ph.D. in Electrical Engineering, December 2011
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