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Title: ADVANCES IN VEHICLE-TERRAIN INTERACTION MODELING FOR SMALL, RIGID-WHEELED VEHICLES OPERATING ON DEFORMABLE TERRAIN
Creator: Meirion-griffith, Gareth
Date: 2012-04-22, 2012-05
Description: This thesis presents advances in the eld of terramechanics, the study of ve- hicle mobility performance, for small, rigid-wheeled vehicles...
Show moreThis thesis presents advances in the eld of terramechanics, the study of ve- hicle mobility performance, for small, rigid-wheeled vehicles operating on deformable terrain. Speci cally, the thesis proposes new models for vehicle performance model- ing through the development of novel pressure-sinkage equations. The semi-empirical equations of terramechanics, rst developed by Bekker in the 1950s, couple vehicle mobility systems and terrain geotechnical properties to yield an understanding of the manner in which traction is developed o -road. This is important because on de- formable terrain mobility is often limited not by the vehicle's torque or power, but by the strength of the terrain and its ability to support locomotion. Classical terramechanics models have proven to be instrumental in the design, modeling, and operation of large, man-driven vehicles for applications such as agri- cultural, military, and commercial transport. However, these models are not appro- priate for vehicles with wheels less than approximately 50 cm in diameter [MGS11a] [SMGSM08] [RBC02]. This is a critical problem because of the increasing prolifer- ation of small, robotic vehicles. In particular, space agencies such as the National Aeronautics and Space Administration (NASA), the Japanese Aerospace Exploration Agency (JAXA), and the European Space Agency (ESA) have shown great interest in the application of terramechanics to planetary exploration rover mobility. At the inception of the author's research, several independent sources had noted the limited accuracy of classical terramechanics models for small-wheeled vehi- cles. However, an understanding of the cause of these inaccuracies was absent. This thesis provides an understanding of these inaccuracies, their cause, and a solution. Using laboratory experiments, fi eld test data, theoretical development, and vehicle simulation, this thesis proposes a modi fied terramechanics framework for predicting small, rigid-wheel traction.
Ph.D. in Mechanical and Aerospace Engineering, May 2012
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Title: CAPACITY ANALYSIS OF MULTI-RADIO MULTI-CHANNEL (MR-MC) WIRELESS NETWORK
Creator: Li, Hongkun
Date: 2012-11-15, 2012-12
Description: The multi-radio multi-channel (MR-MC) networking provides a generic computing platform for a wide range of next-generation wireless networks,...
Show moreThe multi-radio multi-channel (MR-MC) networking provides a generic computing platform for a wide range of next-generation wireless networks, e.g., wireless mesh networks based on the IEEE 802.16, 4G cellular networks based on the long term evolution (LTE), and cognitive radio networks based on the dynamic spectrum sharing. Multiple radio interfaces and channels allow more flexible network configuration to achieve higher network capacity. However, the capacity of the MR-MC networking is not well studied due to the lack of effective tool addressing the complex interactions of the channel assignment and radio interface allocation problem. Moreover, how to efficiently utilize multiple interfaces and channels is unexplored. Generally, we have the four main contributions in this work. 1) an efficient methodology is proposed to compute the optimal capacity of MR-MC network and the concept of critical set is revealed. 2) two sufficient conditions are developed for the flow assignment, which can be constructed and verified in distributed manner. Both conditions achieve a provable portion of the optimal capacity region. 3) a novel framework and efficient algorithms are developed for the dynamic network control in the MR-MC network. 4) a new routing metric is proposed to consider both delay and interference for path selection, and a routing protocol is designed correspondingly. Specifically, we originally construct a new multi-dimensional conflict graph (MDCG) to describe all the interference relationship in the MR-MC network. Based on MDCG, we formulate a multi-commodity flow (MCF) problem augmented with maximal independent set (MIS) constraint to compute the optimal capacity, so that the optimal capacity planning in MR-MC networks can be transformed from integer programming regime to linear programming regime. We further provide the new concept of critical MIS set, and estimate the upper bound of the size of critical MIS set. Therefore, a heuristic algorithm is designed to systematically compute those MISs, which are more likely to be involved in critical set. Moreover, we develop the sufficient conditions for the flow rate assignment, which achieve viii a provable portion of the optimal capacity region, termed as efficiency ratio. These sufficient constraints could be constructed and verified in the distributed and localized manner. We develop new method to compute the efficiency ratio for each sufficient condition by exploring the disruptively different geometric property of MR-MC networks compared with single radio single channel network. Then we develop a new framework to systematically study the resource allocation problem considering the dynamic network control in the MRMC network. The framework not only facilitates the formulation of throughput-optimal scheduling for the MR-MC network, but also allows us optimally solving the joint resource allocation problem, including routing, channel/interface assignment, flow allocation and scheduling. At last, a new routing metric is proposed to consider not only the transmission delay also queuing delay. In addition, in the MR-MC context, the inter-flow interference and intra-flow interference are taken into account. An AODV-based routing protocol is designed to implement the new metric.
PH.D in Electrical and Computer Engineering, December 2012
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Title: ESSAYS IN ENVIRONMENTAL FINANCE
Creator: Li, Jing
Date: 2013, 2013-07
Description: The Clean Development Mechanism (CDM) is a mechanism de ned in the Ky- oto protocol that incentivizes parties to the protocol to fund...
Show moreThe Clean Development Mechanism (CDM) is a mechanism de ned in the Ky- oto protocol that incentivizes parties to the protocol to fund sustainable development projects in countries that are not party to the protocol. In the rst chapter of this paper, I introduce the CDM and how the nancing mechanism works. In the second chapter, I analyze a target contract nancing structure for di erent CDM projects in order to see under what conditions the nancing structure is e cient and to explore the contract's allocation of pro t among the rms. In the two broad categories of CDM projects I consider, I nd the optimal investment decision for the investor and for the overall system. I also analyze how the residual value of technology would a ect the nancing, target contract's e ciency, and allocation of pro t. In the third chapter, I conduct empirical analysis on the actual CDM outputs, Certi ed Emission Reduction units (CERs), for a sample of wind CDM projects in China. I nd that CDM projects greatly under perform relative to the promises they make. Based on this under-performing records, in the fourth chapter, I analyze the economic bene ts investors could gain if they were able to directly fund a portfolio of CDM projects and obtain returns from the anticipated CER issuances and underlying energy generated from the portfolio of CDM projects. I consider a variety of funding constraints that the CDM fund/portfolio manager (CDM-PM) may face and determine their economic performance against actual CDM project data for wind CDM projects in China.
PH.D in Management Science, July 2013
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Title: VISUAL TRAINING AT ILLINOIS INSTITUTE OF TECHNOLOGY: AESTHETICS IN ARCHITECTURAL EDUCATION
Creator: Jones, Kristin
Date: 2016, 2016-05
Description: Over the course of 78 years, an aesthetic ideal which embodies architectural values has been collectively cultivated through Visual Training...
Show moreOver the course of 78 years, an aesthetic ideal which embodies architectural values has been collectively cultivated through Visual Training at the Illinois Institute of Technology (IIT) school of architecture in Chicago. This dissertation provides a comprehensive explanation of Visual Training as it has been conducted at IIT. It promotes a better understanding of the background of Visual Training, the pedagogical practice of the Visual Training exercises, and the ongoing value of the course. The dissertation traces the underpinnings of Visual Training through the writings of Walter Peterhans, founder and Professor of Visual Training at IIT from 1938-1960, Ludwig Mies van der Rohe, Professor and Director of Architecture at IIT from 1938-1958 and other key figures. The thesis shows how the Visual Training program at IIT was influenced by movements in philosophy and mathematics in early 20th century Germany and how existing pedagogy at the Bauhaus was adapted to serve its aim. The dissertation includes an explanation of each exercise in the Visual Training program. It makes explicit the point of each exercise, how each one is conducted and why. Original detailed descriptions, illustrated with examples, show what a student gains from each exercise and how the process of performing the exercise achieves that end. The dissertation compares the way in which the Visual Training program originally developed in relation to other courses in the architecture curriculum to disclose the meaning of architecture, and what has happened in Visual Training as the architecture program at IIT has continued to evolve. The thesis brings to light enduring epistemological tensions underlying architectural education.
Ph.D. in Architecture, May 2016
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Title: Polymorphic Network-on-Chip Datapath Architecture for Reconfigurable Computing Machines
Creator: Weber, Joshua
Date: 2012-04-18, 2012-05
Description: Polymorphic processors have considerable advantages in performance over existing reconfigurable designs. Polymorphic processors combine the...
Show morePolymorphic processors have considerable advantages in performance over existing reconfigurable designs. Polymorphic processors combine the flexibility and ease of a general purpose processor with the performance optimizations made possible through reconfigurable arrays. Polymorphic processors provide all the ease of programming from a traditional general purpose processor while incorporating the significant performance gains that can be realized using reconfigurable arrays. Polymorphic processors can be categorized by the level of integration between the general purpose processor and the reconfigurable array. At coarse levels of integration, the processor and reconfigurable array execute independently and exchange data utilizing bus structures. These systems perform robustly for high level datadriven optimizations, allowing large segments of processing to be quickly performed on fast reconfigurable resources. However, the overhead of data transfer between the processor and array limits the benefit to fine grained optimizations. Other architectures attempt a tight coupling of reconfigurable arrays, placing them within the processor as reconfigurable coprocessors and functional units. This technique allows fine grained optimizations of small scale, highly repeated computations, but finds it difficult to replicate the gains made in large coarse grained optimizations. To achieve an even more tightly coupled design than any prior work, the fundamental architecture of the processor is changed. The datapath of the processor is eliminated and replaced with a network-on-chip communications framework. This framework connects a system of reconfigurable arrays. Some of these reconfigurable blocks are tasked with execution of standard, general purpose processor computations, emulating the standard pipeline stages of a SPARC processor. Additional reconfigurable blocks are available to the end-user to incorporate custom application specific optimizations. This new polymorphic NoC datapath (PolyNoC) processor is able to provide a more tightly integrated architecture with significant performance advantages. The PolyNoC processor is able to incorporate both fine and coarse grained optimizations, producing a polymorphic processor able to provide performance improvements for a wide range of target applications. This thesis presents the architectural design of the PolyNoC processor. The unique design constraints resulting from the use of the NoC as a datapath will be fully explored. The impact of these constraints will be incorporated into the design of a suitable NoC for the PolyNoC processor. A cycle-accurate simulator of the PolyNoC processor has been constructed. This simulator is used to examine the performance of the PolyNoC processor when executing unmodified, industry standard benchmark programs. To demonstrate the advantages of application specific extensions to the processor, accelerators are added for each benchmark. The performance of the Poly- NoC processor is promising.
Ph.D. Computer Science, May 2012
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Title: CYBER ATTACKS AGAINST STATE ESTIMATION IN POWER SYSTEMS: VUNERABILITY ANALYSIS AND PROTECTION STRATEGIES
Creator: Liu, Xuan
Date: 2015, 2015-07
Description: Power grid is one of the most critical infrastructures in a nation and could suffer a variety of cyber attacks. With the development of Smart...
Show morePower grid is one of the most critical infrastructures in a nation and could suffer a variety of cyber attacks. With the development of Smart Grid, cyber security has become an area of growing concern. False data injection attack has recently attracted wide research interest. This thesis proposes a false data attack model with incomplete network information and develops optimal attack strategies for attacking load measurements and the real-time topology of a power grid. The impacts of false data on the economic and reliable operations of power systems are quantitatively analyzed in this thesis. To mitigate the risk of cyber attacks, a distributed protection strategies are also developed. It has been shown that an attacker can design false data to avoid being detected by the control center if the network information of a power grid is known to the attacker. In practice, however, it is very hard or even impossible for an attacker to obtain all network information of a power grid. In this thesis, we propose a local load redistribution attacking model based on incomplete network information and show that an attacker only needs to obtain the network information of the local attacking region to inject false data into smart meters in the local region without being detected by the state estimator. A heuristic algorithm is developed to determine a feasible attacking region by obtaining reduced network information. This thesis investigates the impacts of false data on the operations of power systems. It has been shown that false data can be designed by an attacker to: 1) mask the real-time topology of a power grid; 2) overload a transmission line; 3) disturb the line outage detection based on PMU data. To mitigate the risk of cyber attacks, this thesis proposes a new protection strategy, which intends to mitigate the most damaging effect of LR attacks on power system operation. The objective is to mitigate the damage effects of false data injection attacks by increasing the attacking cost of an attacker. This is achieved by protecting a small set of critical measurements. To further reduce the computation complexity, we also propose a mixed integer linear programming approach to separate the power grid into several subnetworks, then distributed protection strategy is applied to each subnetwork. The results of this thesis reveal the mechanism of local false data injection attacks and highlight the importance and complexity of defending power systems against false data injection attacks.
Ph.D. in Electrical and Computer Engineering, July 2015
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Title: TEMPORAL AND SPATIOTEMPORAL MODELS FOR SHORT-CRIME PREDICTION
Creator: Liu, Xiaomu
Date: 2017, 2017-07
Description: One of the most important aspects of predictive policing is identifying the likely time and place of crime occurrences so as to prevent future...
Show moreOne of the most important aspects of predictive policing is identifying the likely time and place of crime occurrences so as to prevent future crimes. The ability to make short-term predictions may be of particular importance for optimizing police resource allocation. The goal of this study is to investigate the temporal and spatiotemporal pattern of crime in the city of Chicago and to build corresponding predictive models. First, a temporal model for forecasting citywide violent crime time count is proposed. This model is composed of a long-term trend and short-term variations using data of time, weather and crime. The importance of model reproducibility is addressed in this study to produce low-complexity models. We introduce an approach that provides a way to extend the model selection criterion to both prediction accuracy and model reproducibility. The experimental results show that models produced by this approach outperform several simple time-series models. It is also found that these models typically include fewer variables; therefore, they are more interpretable, and may provide superior generalization error. Next we develop a framework that provides predictions for tomorrow’s violent crime counts at the level of a police district. The procedures include citywide daily violent crime count prediction, violent crime density estimation, and distributing citywide predictions to districts according to the estimated densities. In order to estimate the crime spatial densities, we use mesh modeling and demonstrate that a mesh model can be used as the structure for modeling the spatial variation of crime rate since it is well adapted to the inhomogeneous crime distribution. The experimental results show that our method provides more-accurate forecasts than those given by historical crime statistics. One aspect of studying spatial pattern of crimes is identifying geographical regions with similar crime characteristics. Specifically, we illustrate applying unsupervised clustering techniques to segment the city into sub-regions. We explore the use of Gaussian mixture models combined with a Markov random field for the purpose of regularization. We also propose a framework for the evaluation of clustering models without knowing the ground truth, which can present a more-complete picture for model selection in unsupervised clustering problems. Finally, we develop a spatiotemporal prediction method that predicts the locations where violent crimes or property crimes are most likely to occur tomorrow. Crime incidents are rasterized by a spatiotemporal grid. Other factors that affect the time and location preferences of criminal activities are also leveraged and represented by that grid. Each spatiotemporal grid cell is treated as an example for training and testing our models. We also explore whether pooling data from various sub-regions based on spatial clustering can improve model performance. The experimental results show that our models are more accurate than conventional hot-spot models. It is found that the effects of using different training samples are not consistent, which depends on target crime type.
Ph.D. in Electrical Engineering, July 2017
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Title: ALTERNATIVE APPROACH TO VOLATILITY FORECASTING AND EVALUATING FORECASTING PERFORMANCE
Creator: Lim, Hyungjin
Date: 2012-10-08, 2012-12
Description: Studies in the volatility process of financial markets have focused more on volatility modeling aspects, using parametric assumptions....
Show moreStudies in the volatility process of financial markets have focused more on volatility modeling aspects, using parametric assumptions. Compared with the vast amount of research in parametric modeling, there is a lack of studies in nonparametric approaches in volatility forecasting and forecasting performance evaluation. This research intends to explore alternative approaches to forecasting volatility of financial returns, and evaluation of forecasting models. This research will employ grammatical evolution to propose a hybrid forecasting model that utilizes the benefits of parametric and genetic programming models. Furthermore, an alternative methodology to handle structural breaks in volatility is examined by utilizing an adaptive approach in dynamic environments. In an extensive empirical study, the proposed models will be compared with the other models widely used in the literature using statistical and economic tests. Specifically, as an alternative to the statistical performance evaluation measure, a nontraditional method derived from the idea of speculating on asset volatility will be employed to compare the performance as well as to assess economic usefulness of competing volatility models. The hybrid model provided superior forecasting performance than traditional techniques both on economic and statistical measures.
PH.D in Management Science, December 2012
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Title: THEORETICAL ANALYSIS OF REAL-TIME SCHEDULING ON RESOURCES WITH PERFORMANCE DEGRADATION AND PERIODIC REJUVENATION
Creator: Hua, Xiayu
Date: 2017, 2017-07
Description: In 1973, Liu and Layland [81] published their seminal paper on schedulability analysis of real-time system for both EDF and RM schedulers. In...
Show moreIn 1973, Liu and Layland [81] published their seminal paper on schedulability analysis of real-time system for both EDF and RM schedulers. In this work, they provide schedulability conditions and schedulability utilization bounds for both EDF and RM scheduling algorithms, respectively. In the following four decades, scheduling algorithms, utilization bounds and schedulability analyses for real-time tasks have been studied intensively. Amongst those studies, most of the research rely on a strong assumption that the performance of a computing resource does not change during its lifetime. Unfortunately, for many long standing real-time systems, such as data acquisition systems (DAQ) [74, 99], deep-space exploration programs [120, 119] and SCADA systems for power, water and other national infrastructures [121, 26], the performance of computational resources suffer notably performance degradations after a long and continuous execution period [61]. To overcome the performance degradation in long standing systems, countermeasures, which are also called system rejuvenation approaches in the literature [123, 61, 126], were introduced and studied in depth in the last two decades. Rejuvenation approaches recover system performance when being invoked and hence benefit most long standing applications [30, 102, 11, 12, 39]. However, for applications with real-time requirements, the system downtime caused by rejuvenation process, along with the decreasing performance during the system’s available time, makes the existing real-time scheduling theories difficult to be applied directly. To address this problem, this thesis studies the schedulability issues of a realtime task set running on long standing computing systems that suffers performance degradation and uses rejuvenation mechanism to recover. Our first study in the thesis focus on a simpler resource model, i.e. the periodic resource model, which only considers periodic rejuvenations. We introduce a method, i.e., Periodic Resource Integration, to combine multiple periodic resources into a single equivalent periodic resource and provide the schedulability analysis based on the combined periodic resource for real-time tasks. By integrating multiple periodic resources into one, existing real-time scheduling researches on single periodic resource can be directly applied on multiple periodic resources. In our second study, we extend the periodic resource mode to a new resource model, the P2-resource model, in our second work to characterize resources with both the performance degradation and the periodic rejuvenation. We formally define the P2-resource and analyze the schedulability of real-time task sets on a P2-resource. In particular, we first analyze the resource supply status of a given P2-resource and provide its supply bound and linear supply bound functions. We then developed the schedulability conditions for a task set running on a P2-resource with EDF or RM scheduling algorithms, respectively. We further derive utilization bounds of both EDF and RM scheduling algorithms, respectively, for schedulability test purposes. With the P2-resource model and the schedulability analysis on a single P2- resource, we further extend our work to multiple P2-resources. In this research, we 1) analyze the schedulability of a real-time task set on multiple P2-resources under fixedpriority scheduling algorithm, 2) introduce the GP-RM-P2 algorithm and 3) provide the utilization bound for this algorithm. Simulation results show that in most cases, the sufficient bounds we provide are tight. As the rejuvenation technology keeps advancing, many systems are now able to perform rejuvenations in different system layers. To accommodate this new advances, we study the schedulability conditions of a real-time task set on a single P2-resource with both cold or warm rejuvenations. We introduce a new resource model, the P2-resource with duel-level rejuvenation, i.e., P2D-resource, to accommodate this new feature. We first study the supply bound and the linear supply bound of a given P2D-resource. We then study the sufficient utilization bounds for both RM and EDF scheduling algorithms, respectively.
Ph.D. in Computer Science, July 2017
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Title: CONTRIBUTIONS TO ALGORITHMIC MATROID PROBLEMS
Creator: Huang, Jinyu
Date: 2015, 2015-07
Description: In this thesis, we obtain several algorithms for problems related to matroids, a structure that generalizes the concept of linear independence...
Show moreIn this thesis, we obtain several algorithms for problems related to matroids, a structure that generalizes the concept of linear independence in a vector space and an acyclic subgraph structure in a graph. Matroids have been widely applied in combinatorial optimization, graph theory, coding theory and so forth. Specifically, our results include: In this thesis, we present a constant-competitive online algorithm of the matroid secretary problem for the partition matroids without information of the partition and for the paving matroids. We also introduce the multi-objective matroid secretary problem that extends the matroid secretary problem, in which the weight function is a k-vector w = [w1, · · · , wk]. We show a constant competitive algorithm of the multiobjective matroid secretary problem for the uniform matroids and for the paving matroids. Since bases of a matroid generalize many important combinatorial structures, many counting problems can be expressed as a problem that counts the number of bases of a matroid. An efficient approximate counting algorithm can be designed provided that a rapidly-mixing Markov chain that samples bases of a matroid can be constructed. Let Φ(G) be the conductance of the base-exchange graph G. Matroid- Expansion Conjecture (1989, Mihai and Vazirani) states that Φ(G) ≥ 1 for any base-exchange graph G of a matroid, which implies an FPRAS (fully-polynomial randomized approximation scheme) for counting the number of bases of a matroid. We use λ2, the second smallest eigenvalue of L, the discrete Laplacian matrix of G, to prove the Matroid-Expansion Conjecture for any paving matroid, for any balanced matroid, and for the direct sum of a paving matroid with a balanced matroid. A maximum linear matroid parity set is called a basic matroid parity set, if its size is the rank of the matroid. We show that determining the existence of a common base (basic matroid parity set) for linear matroid intersection (linear matroid parity) is in NC2, provided that there are polynomial number of common bases (basic matroid parity sets). For graphic matroids, we show that finding a common base for matroid intersection is in NC2, if the number of common bases is polynomial bounded. We also give a new RNC2 algorithm that finds a common base for graphic matroid intersection. Finally, we prove that if there is a black-box NC algorithm for PIT (Polynomial Identity Testing), then there is an NC algorithm to determine the existence of a common base (basic matroid parity set) for linear matroid intersection (linear matroid parity).
Ph.D. in Applied Mathematics, July 2015
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Title: ANTI-TUMOR SPLICING: RESTORING THE TUMOR SUPPRESSOR BAX IN MICROSATELLITE UNSTABLE TUMORS
Creator: Haferkamp, Bonnie
Date: 2011-11, 2011-12
Description: Microsatellite instability (MSI) is a hallmark for many tumors, especially colon, endometrial, gastric and bladder. Bax, a tumor suppressor...
Show moreMicrosatellite instability (MSI) is a hallmark for many tumors, especially colon, endometrial, gastric and bladder. Bax, a tumor suppressor and pro-death Bcl-2 family member, is frequently mutated in MSI tumors. A microsatellite mutation produces a frameshift with premature termination, leading to “Bax-negative” tumors. Although low Bax expression in tumors is often associated with poor prognosis, several studies have correlated lack of Bax in MSI tumors with improved prognosis. However, the molecular explanation for this paradox is unknown. Here we show that “Bax-negative” tumors in fact generate a novel family of anti-tumor Bax-MSI isoforms through alternative splicing. The thesis includes two parts. In Chapter One, we fully characterize one Bax-MSI isoform, BaxΔ2. We show that BaxΔ2 is detrimental to cancer cells but through a non-conventional death pathway, with differential sensitivity to chemotherapeutics. In Chapter Two, we present an entire family of Bax-MSI isoforms, and illustrate a potential molecular mechanism behind its production. We show that the frequency of Bax alternative splicing is significantly higher in MSI than non-MSI tumors, and that BaxΔ2 trans splicing requirements are ubiquitous in human cell lines. The discovery of functional Bax isoforms in Bax-mutated tumors may help explain why the apparent loss of Baxα in tumors is sometimes associated with a better prognosis. In addition, the unique sequences of Bax-MSI isoforms can serve as biomarkers for diagnostic and treatment purposes. Importantly, identification of Bax-MSI isoforms will provide a great opportunity from a genetic approach or drug design for treatment of MSI cancer.
Ph.D. in Biology, December 2011
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Title: DYNAMIC ANALYSIS OF UNCERTAIN STRUCTURES USING IMPRECISE PROBABILIY
Creator: Bergerson, Joshua D.
Date: 2014, 2014-05
Description: A new method for dynamic response spectrum analysis of structures with uncertainty in their mechanical properties utilizing the notion of...
Show moreA new method for dynamic response spectrum analysis of structures with uncertainty in their mechanical properties utilizing the notion of imprecise probability is developed. This finite-element-based method is capable of obtaining probabilistic bounds of the dynamic response of the structure with uncertainty defined by enveloping p-boxes. The developed method obtains probabilistic bounds on 1) the mode shapes, 2) modal coordinates, and 3) modal participation factor, leading to the p-boxes of modal responses. Finally maximum modal responses are combined to obtain the structure’s maximum total response with consideration of uncertainty. Numerical examples demonstrating the developed method are included. Keywords: Structural Dynamics, Uncertainty, Imprecise Probability, P-Box.
PH.D in Civil Engineering, May 2014
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Title: PREDICTING CORTICAL RESPONSE DURING TRANSCRANIAL MAGNETIC STIMULATION IN HUMANS
Creator: Krieg, Todd
Date: 2014, 2014-07
Description: Transcranial magnetic stimulation (TMS) is capable of noninvasively activating neurons in the brain. TMS can induce persistent effects and is...
Show moreTranscranial magnetic stimulation (TMS) is capable of noninvasively activating neurons in the brain. TMS can induce persistent effects and is being increasingly used in both clinical and research applications. Despite this growing interest, the relationship between TMS-generated electric fields (E-fields) and specific cortical electrophysiological responses is not well understood. Most analytical approaches focus on applied magnetic field strength in the target region as the primary factor, placing activation on the gyral crowns. However, imaging studies show cortical targets are typically located in the sulcal banks. To study this causal relationship, we combined subject-specific detailed finite element modeling (FEM) to calculate induced E-field information and employed concurrent TMS-PET data as a measure of cortical response. The research presented in this work is divided into three main parts, each one building on the results of the previous: (1) We determined that neocortical surface orientation was a critical determinant of regional activation by studying the locations of activation during TMS on the cortical surface. Results indicated that brain activations were primarily sulcal for both the TMS and task activations. This study provided further evidence that a major factor in cortical activation during TMS is the orientation of the cortical surface with respect to the induced E-fields. This was demonstrated by the fact that the sulcal bank of the primary motor cortex had larger cerebral blood flow (CBF) responses during TMS despite the gyral crown of the cortex being subjected to a larger magnetic field magnitude. (2) We sought to determine the E-field characteristics that lead to cortical activation. We found that decomposing the E-field into orthogonal vector components based on the cortical surface geometry (and hence, cortical neuron directions) led to significant differences between the regions of cortex that were active and non-active. Specifically, active regions had significantly higher E-field components in the normal orthodromic direction (i.e., parallel to pyramidal neurons in the dendrite-to-axon orientation) and in the tangential direction (i.e., parallel to interneurons) at high spatial gradient. In contrast, nonactive regions had higher E-field vectors in the antidromic normal direction. This provides important new understanding of the factors by which TMS induces cortical activation necessary for predictive and repeatable use of this noninvasive stimulation modality. (3) Finally, two different but related algorithms were formulated using different optimization approaches that provide a means for predicting topographical maps of cortical activation in humans. This is the first study to produce an algorithm for predicting the electrophysiological responses of neurons in the cortex based on both gross and microscopic brain anatomy correlated to relevant experimental recordings. This new innovation could provide an invaluable tool for predicting regions of cortical activation that may permit, among other benefits, improved prescriptive TMS protocols to optimize therapeutic response to TMS treatment.
Ph.D. in Biomedical Engineering, July 2014
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Title: AN AUTOMATED ENGINEERING PROCESS TO VERIFY THE CORRECT COORDINATION OF MULTILAYER RECOVERY
Creator: Kroculick, Joseph
Date: 2017, 2017-05
Description: Recovery is a critical function in backbone networks. The primary function of recovery is to provide connectivity regardless of which layer...
Show moreRecovery is a critical function in backbone networks. The primary function of recovery is to provide connectivity regardless of which layer recovery operates at. Another function of recovery is for all services traversing a failed link to be restored in a way that is consistent with a service user’s requirements. These requirements can include the consideration of factors such as (1) the cost of recovery, (2) the amount of traffic restored, and (3) the delay in restoring units of traffic. With more options available to recover traffic, providing an integrated recovery solution is necessary. An important force driving the evolution of network devices to transport services such as IP traffic is the layering of network resources. Layering enables networks to increase capacity by extending legacy SONET networks to interface with optical wavelengths. Inconsistent provisioning can prevent service continuity from being achieved during a failure. Continuity of service has been recognized as one key business goal. Furthermore, since recovery can occur at a different time than when it is provisioned, inconsistent provisioning is determined after the fact, with services left unrepaired, repaired unnecessarily at an extra cost, or not repaired fast enough. A network manager can check if recovery is consistent with a global perspective on how traffic should be restored by comparing the provisioning at each device against suitable properties of a formal representation. To address this issue an engineering method was developed to detect errors in provisioning automated recovery processes in multilayer and multiprotocol transport networks. This dependability assessment process (DAP) leverages inference techniques provided by Semantic Web technologies in order to detect network-device provisioning errors. Provisioning should be accompanied by methodologies, processes, and activities to ensure that it can be trusted to achieve a desired network state. The DAP takes into account unique constraints in the telecommunications domain including bottom-up evolution of physical layer technologies to provide connectivity, and lack of a universal model of network functionality. This method is applied to assessing the correctness of provisioning decisions for a protection switching application in a transport network in both the spatial and temporal domains.
Ph.D. in Computer Science, May 2017
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Title: ANANALYSIS OF ZOO AND AQUARIUM PROVIDED TEACHER PROFESSIONAL DEVELOPMENT
Creator: Kubarek-sandor, Joy
Date: 2014, 2014-12
Description: Informal science institutions are a significant provider of science teacher professional development. As pressure continues to critically...
Show moreInformal science institutions are a significant provider of science teacher professional development. As pressure continues to critically analyze the work of teachers and their effectiveness in the classroom, it is important to understand how informal science institutions contribute to effective change in teacher science content knowledge and pedagogy. This research study analyzed zoo and aquarium provided teacher professional development to respond to the research questions: How do zoos and aquaria determine and assess their goals for teacher professional development? How do these goals align with effective teacher change for science content knowledge and pedagogy? Theoretical frameworks for high quality teacher professional development, effective evaluation of teacher professional development, and learning in informal science settings guided the research. The sample for the study was AZA accredited zoos and aquariums providing teacher professional development (N=107). Data collection consisted of an online questionnaire, follow-up interviews, and content analysis of teacher professional development artifacts. Analysis revealed that by and large zoos and aquariums are lacking in their provision of science teacher professional development. Most professional development focuses on content or resources, neglecting pedagogy. Assessments mismatch the goals and rely heavily on self-report and satisfaction measures. The results demonstrate a marked difference between those zoos and aquariums that are larger in capacity versus those that are medium to small in size. This may be an area of research for the future, as well as analyzing the education resources produced by zoos and aquariums as these were emphasized heavily as a way they serve teachers.
Ph.D. in Mathematics and Science Education, December 2014
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Title: DEVELOPING ALGORITHMIC TRADING STRATEGIES AND EMPIRICAL ANALYSIS WITH HIGH FREQUENCY TRADING DATA
Creator: Lee, Jeonghoe
Date: 2015, 2015-07
Description: The PhD dissertation research topics aim at developing algorithmic trading strategies and demonstrating data analysis skills. To be a...
Show moreThe PhD dissertation research topics aim at developing algorithmic trading strategies and demonstrating data analysis skills. To be a quantitative analyst as well as an academic scholar in financial trading area, these two professional backgrounds are indispensable. In detail, chapter 1 shows multi-objective optimization and spontaneous optimization of design variables. For instance, while conventional trading systems explore a single objective function, multi-objective optimization allows us to manage the essential trade-off among profit, standard deviation and maximum-drop. In addition, design parameters such as trading volume, the amount of historical data, and trading gateways of technical indicators are continuously optimized in real time. In chapter 2, this chapter shows an algorithmic trading system with the concept of machine learning, and demonstrating its various applications. The main purpose of this research is to propose objective numerical development framework in algorithmic trading. Chapter 3 pursues understanding liquidity measures which are critical for algorithmic traders and investors. Various liquidity measures have been suggested and they have different sensitivities to the market. This research analyzes liquidity measures and clarifies the relation between market price return & realized volatility and liquidity measures. In sum, with these three chapters, this dissertation will demonstrate necessary research topics in algorithmic trading.
Ph.D. in Management Science, July 2015
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Title: STABILITY OF AQUEOUS FOAMS: FOAM FILM STRATIFICATION PHENOMENON AND THE EFFECTS OF DISPERSED VERSUS SOLUBILIZED OIL
Creator: Lee, Jongju
Date: 2016, 2016-05
Description: A foam is a system consisting of a concentrated dispersion of gas bubbles in a liquid. Foams are encountered in many industries such as food,...
Show moreA foam is a system consisting of a concentrated dispersion of gas bubbles in a liquid. Foams are encountered in many industries such as food, agriculture, chemicals, petroleum, and paper manufacturing. Aqueous foams are formed by using surfactants or nano-colloidal particles. Thin liquid films containing surfactant micelles or other nano-colloidal particles are considered to be the key structural elements of foams containing gas and liquid. We thus probed the effects of the micellar concentration and the film size (area) on the stability of a dry bulk foam by studying the stability of a single foam lamella containing micelles; this is so we can establish the importance of the micellar structuring phenomenon and the foam film size (area) affecting the bulk foam stability. The film stratification phenomenon (stepwise film thinning) was experimentally observed by the reflected light microinterferometry. The stepwise layer-by-layer decrease of film thickness is due to the appearance and growth of dark spot (of one layer less film thickness) in the film. We used the two-dimensional diffusion model to model the dynamics of dark spot expansion considering the apparent diffusion coefficient and the film size. Based on this model, we carried out a parametric study depicting the effects of film thickness (or the number of micellar layers) and film area on the rate of dark spot expansion. Many practical applications involving three-phase foams (aqueous foams containing oil) commonly employ surfactants at several times their critical micelle concentration (CMC). We investigated the influence of both the dispersed and solubilized oils, and the surfactant concentration (above CMC) on the stability of an aqueous foaming system. In foam stability, the relative importance of the dispersed oil versus oil solubilized within the micelles depends on the stability of the aqueous asymmetric (i.e., pseudoemulsion) film between the oil and the air-water interface and the second virial coefficient. Also, the micellar structuring phenomenon tests using the single foam lamella revealed that the multi-layering structure was well pronounced in the absence of the solubilized oil; as a consequence, the foam lamellae thinned slowly layer-by-layer and the oil solubilized in micelles weakened the micellar structure formation. The foam lamellae thinned faster, making the foam less stable.
Ph.D. in Chemical Engineering, May 2016
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Title: HYBRID METHODS FOR SIMULATION OF MUON IONIZATION COOLING CHANNELS
Creator: Kunz, Josiah D.
Date: 2017, 2017-05
Description: COSY Infinity is an arbitrary-order beam dynamics simulation and analysis code. It can determine high-order transfer maps of combinations of...
Show moreCOSY Infinity is an arbitrary-order beam dynamics simulation and analysis code. It can determine high-order transfer maps of combinations of particle optical elements of arbitrary field configurations. For precision modeling, design, and optimization of next-generation muon beam facilities, its features make it a very attractive code. New features are being developed for inclusion in COSY to follow the distribution of charged particles through matter. To study in detail some of the properties of muons passing through material, the transfer map approach alone is not sufficient. The interplay of beam optics and atomic processes must be studied by a hybrid transfer map–Monte Carlo approach in which transfer map methods describe the average behavior of the particles in the accelerator channel including energy loss, and Monte Carlo methods are used to provide small corrections to the predictions of the transfer map accounting for the stochastic nature of scattering and straggling of particles. The advantage of the new approach is that it is very efficient in that the vast majority of the dynamics is represented by fast application of the high-order transfer map of an entire element and accumulated stochastic effects as well as possible particle decay. The gains in speed shown in this work are expected to simplify the optimization of muon cooling channels which are usually very computationally demanding due to the need to repeatedly run large numbers of particles through large numbers of configurations. This work describes the development of the required algorithms and their application to the simulation of muon ionization cooling channels. The code is benchmarked against other codes, validated with experimental results, and predicts results for current muon ionization cooling efforts.
Ph.D. in Physics, May 2017
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Title: ACOUSTIC LOCALIZATION OF BREAKDOWN IN RADIO FREQUENCY ACCELERATING CAVITIES
Creator: Lane, Peter
Date: 2016, 2016-07
Description: Current designs for muon accelerators require high-gradient radio frequency (RF) cavities to be placed in solenoidal magnetic fields. These...
Show moreCurrent designs for muon accelerators require high-gradient radio frequency (RF) cavities to be placed in solenoidal magnetic fields. These fields help contain and efficiently reduce the phase space volume of source muons in order to create a usable muon beam for collider and neutrino experiments. In this context and in general, the use of RF cavities in strong magnetic fields has its challenges. It has been found that placing normal conducting RF cavities in strong magnetic fields reduces the threshold at which RF cavity breakdown occurs. To aid the effort to study RF cavity breakdown in magnetic fields, it would be helpful to have a diagnostic tool which can localize the source of breakdown sparks inside the cavity. These sparks generate thermal shocks to small regions of the inner cavity wall that can be detected and localized using microphones attached to the outer cavity surface. Details on RF cavity sound sources as well as the hardware, software, and algorithms used to localize the source of sound emitted from breakdown thermal shocks are presented. In addition, results from simulations and experiments on three RF cavities, namely the Aluminum Mock Cavity, the High-Pressure Cavity, and the Modular Cavity, are also given. These results demonstrate the validity and effectiveness of the described technique for acoustic localization of breakdown.
Ph.D. in Physics, July 2016
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Title: MATERIAL INVENTORY CONTROL AND MANAGEMENT SYSTEM IN CONSTRUCTION USING GIS APPLICATIONS AND A "HYBRID" TRACKING SYSTEM
Creator: Le, Kiet Tuan
Date: 2017, 2017-05
Description: Material inventory control and management is simply the process by which an organization is supplied with the goods and services that it needs...
Show moreMaterial inventory control and management is simply the process by which an organization is supplied with the goods and services that it needs to achieve its objectives of buying, storing and moving materials. There are usually plenty of materials in a construction site. A large amount of stored materials can meet unexpected demands, and can prevent future purchases that can be affected by an escalation of material prices. However, a large amount of stored materials can also cause negative impacts such as increased costs for storing redundant inventory, and decreased construction productivity. Therefore, a proper material inventory control and management system is critical for economy and efficiency in construction projects. A material inventory control and management system consists of two main elements: inventory control and inventory management. Inventory control is the process of monitoring the flow of materials on the construction site beginning when materials are received from manufacturers and ending when those materials are used in production. Inventory management is the practice overseeing and managing the ordering, storage and use of materials on the construction site. In this study, an automated material inventory control and management system is developed using Geographical Information System (GIS) applications and a “hybrid” tracking system to identify the need for materials, order, track, transport, store, control the inventory, circulate on site, and incorporate into production. The proposed system allows users to have access to real-time information about the materials on the construction such as: the arrival of materials, the amount of materials received, the status of materials (either in storage area or in-production), and the up-to-date information about site stocks. Furthermore, the system provides users the ability to make correct and timely decisions regarding materials on the construction site.
Ph.D. in Civil Engineering, May 2017
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