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Title: OPTIMAL DESIGN OF PERMANENT MAGNET SYNCHRONOUS MACHINES BASED ON MAGNETIC FIELD DISTRIBUTION ASSESSMENT AND PERFORMANCE ANALYSIS
Creator: Jiang, Yong
Date: 2015, 2015-05
Description: The detailed magnetic field distribution of a permanent magnet electric motor is very important for the accurate prediction of performance...
Show moreThe detailed magnetic field distribution of a permanent magnet electric motor is very important for the accurate prediction of performance parameters such as back electromotive force (back-EMF), rotor and stator losses, winding inductances, noise and vibration, torque profiles, etc. Although finite element analysis is a good option for accurately calculating magnetic field distribution in electrical machines, it is typically timeconsuming and does not provide closed form solutions. Alternatively, analytical calculation of magnetic field distribution can be conducted in Fourier series, which is more suitable for a design tool to predict the motor performance. This dissertation presents a novel numerical technique for calculating exact magnetic field distribution in the air gap of a surface mounted permanent magnet machine. This solution can be obtained via a two-dimension analytical solution with Laplacian and quasi-Poisonian equations, assuming that the iron is infinitely permeable and the air gap is slotless. Slot effects can be added in the model by using relative air gap permeance calculated by the conformal transformation of slot geometry. This technique is constructed by multiplying the relative permeance function expressed in an infinite Fourier series with the distribution of magnetic field in the slotless air gap. This method shows a very good alignment with finite element method for a surface mounted permanent magnet machine with radial magnetization. It can also be extended to calculating magnetic field distribution of interior permanent magnet motors including consideration of magnetic saturation, crosssaturation between d-axis and q-axes, affecting both inductances and flux linkages, as well as localized effects due to rotor bridges. Furthermore, this approach can be used to create a closed-form solution, which is the first step towards inverse modeling of electric machines. This is a complete paradigm shift in the design process for electric machines, which can reduce the time taken to design an electric machine, while reducing the active material content to make them power dense with significant reduction in cost. Furthermore, availability of analytical description of the field components will aid in the designer’s ability to distinguish between the control and magnetic design aspects.
Ph.D. in Electrical and Computer Engineering, May 2015
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Title: SPECTRALLY ACCURATE BOUNDARY INTEGRAL METHOD FOR FREE SURFACES IN STOKES FLOW
Creator: Kuang, Yin
Date: 2011-04-18, 2011-05
Description: spectrally accurate boundary integral method is developed for solving the velocity of the film flow with suspended particles down an inclined...
Show morespectrally accurate boundary integral method is developed for solving the velocity of the film flow with suspended particles down an inclined plane in Stokes flow. The problem is a two-dimensional gravity-driven film flow with a rigid particle flowing down an inclined plane. We present the governing equations and the numerical methods for solving it with the help of periodic Green’s function. To obtain the system of discretized equations, we discuss the smoothness of each integrand appearing in the boundary integral formulation and use the composite trapezoidal rule for smooth periodic integrands to achieve the spectral accuracy. For the weakly singular integral, we approximate it by a special spectrally accurate quadrature. The Krylov subspace iterative method GMRES is employed to solve the resulting linear system. This method can be also applied to compute the velocity of interface in some other cases of film flow.
M.S. in Applied Mathematics, May 2011
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Title: OPTIMAL DECISION-MAKING OF INTERDEPENDENT TRANSPORTATION INVESTMENT ALTERNATIVES UNDER RISK AND UNCERTAINTY
Creator: Zhou, Bei
Date: 2012-07-12, 2012-07
Description: With increasing demand for a more efficient transportation system and decreasing budget levels, transportation investment decision-making that...
Show moreWith increasing demand for a more efficient transportation system and decreasing budget levels, transportation investment decision-making that aims to select the optimal project portfolio which yields maximized overall networkwide benefits in terms of economy, society and environment has increasingly become important. This dissertation has conducted an in-depth investigation into project evaluation and project selection that are crucial steps of transportation decision-making. It begins with information search through a review of existing methods for project evaluation and selection. Several limitations of existing methods have been revealed. In particular, they are in lack of considerations in network impacts of a single investment project, interdependencies of simultaneously implementing multiple projects, and restrictions of total risk of overall benefits of selected projects within an acceptable level. Then, a new methodology is proposed for networkwide traffic assignments, project evaluation, and project selection. A state-of-art large scale transportation simulation software, the TRansportation ANalysis and SIMulation System (TRANSIMS) toolbox, is utilized to perform networkwide dynamic traffic assignments to general redistributed traffic volumes after project implementation needed as inputs for project evaluation. For project evaluation, a life-cycle cost analysis approach is developed to consider all agency costs and user costs in the service life-cycle of two primary categories of highway facilities: pavements and bridges. In order to enhance the robustness of analytical results, risk and uncertainty of input factors concerning traffic volumes, project costs, and discount rates are incorporated into the life-cycle cost computation using @Risk Palisade software, Version 5.5. For project selection, two-stage enhanced Knapsack model, hypergraph Knapsack, and two-stage hypergraph Knapsack model are proposed to choose the best sub-collection of interdependent projects to yield maximized overall benefits at various budget levels, while controlling the total risk within an acceptable level. In terms of two-stage Knapsack model, the Markowitz mean-variance model is utilized for stage-one optimization to generate minimized total risk of all projects subject to constraints of available budget and minimum benefits to be expected for individual projects. At the second stage, the Knapsack model is enhanced by adding stage-one optimization solution as one more constraint. Such a treatment could help control the total risk of overall benefits of all selected projects at a desirable level. Moreover, a hypergraph Knapsack model is introduced to capture project network impacts and interdependency relationships. In order to simultaneously address issues of networkwide project impacts, interdependencies, and total risk levels, a two-stage hypergraph Knapsack model is developed. Efficient solution algorithms are developed and coded to Frontline Solver Xpress V55 software to solve the two-stage Knapsack model, hypergraph Knapsack model, and two-stage hypergraph Knapsack model, respectively. Three computational studies are performed to apply the proposed methodology using two sets of data, including six-year data on 672 candidate projects proposed by Indiana Department of Transportation for state highway programming and 6 mega projects proposed by Illinois State Toll Highway Authority for tollway network major capital improvements. It has generally found that the use of two-stage Knapsack model could readily control the total risk of overall benefits of selected projects at a desirable level, but it may result in significant changes in the overall benefits for different budget levels where significant differences in risks are associated with individual projects. The hypergraph Knapsack model could effectively handle issues of networkwide project impacts and interdependency relationships. However, the two-stage hypergraph Knapsack model appears to be most robust in that it could simultaneously resolve the issues of networkwide project impacts, interdependency relationships, and total risks of overall project benefits, thus generating most reliable information to support rational transportation investment decision-making.
Ph.D. in Civil Engineering, July 2012
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Title: SPAM DETECTION IN SOCIAL NETWORKS: A CASE STUDY OF WEIBO
Creator: Guo, Chang
Date: 2012-07-11, 2012-07
Description: Online Social Network Service (OSNS) lead the fashion on internet nowadays[43]. Hundreds of millions people are using Facebook, Twitter,...
Show moreOnline Social Network Service (OSNS) lead the fashion on internet nowadays[43]. Hundreds of millions people are using Facebook, Twitter, MySpace and other similar OSNS all over the world[18]. In China, people use Sina Weibo, Tencent Weibo, Renren instead of Facebook and Twitter. With those miracle tools, people communicate with others far from them at real time. However, in the wrong hands, those virtual communicating services are vulnerable from being leveraged to spread harmful or unwelcome spam messages to large number of people instantly. Besides illegal advertisements, the even worse spam messages could mislead you to phishing websites, or malware downloading links. Your account may be compromised and be used by spammers to continue spreading the virus to your acquaintance. The fight with spammers has been over decades. Thousands of smart scholars has developed different strategies to auto filter most of the spam messages[10][12][18]. In E-mail system, the earliest platform leveraged by spammers and hackers, it is reported that 98% of the common spam e-mails could be identified[5]. But in OSNS, it is just the beginning of the fight. In this work, I present a further study on the behavior of spammers and spammer accounts in Sina Weibo, the most popular OSNS in China. From the data I collected, I learn the differences pattern between spammers and legitimate users and try to finally identify the spammers. I study a dataset of 220K user profile data and 2.1 million of their most recent posted tweets. My method could finally recognize 84.4% of the spammer account while the overall classification accuracy achieves 89.9%. Because this method does not rely on the content of messages but the structure and pattern of them, I believe this method should work well for other OSNS such as twitter as well.
M.S. in Computer Science, July 2012
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Title: POWER ELECTRONIC INTERFACE FOR AN OFF-GRID SOLAR POWERED ENERGY STORAGE SYSTEM
Creator: Mao, Yanwen
Date: 2012-10-17, 2012-12
Description: There are about 1.5 billion people in the world with no access to electricity. Of these, a significant number of people live in rural parts of...
Show moreThere are about 1.5 billion people in the world with no access to electricity. Of these, a significant number of people live in rural parts of Africa and Asia. It is very inconvenient and unhealthy for them to work or study at night with the poor light from a candle or kerosene lamp. Additionally, since they do not have a continuous or predictable supply of power, it can be significantly difficult for them to use modern electronic devices such as cell phones, computers or sometimes even basic amenities such as lights and fans. For such situations, an energy storage system powered by solar energy can be a good solution, while being environmentally friendly and easy to use. In this thesis, the design and analysis of an off-grid solar powered energy storage system is presented. It consists of a solar panel, battery pack, control circuit, bidirectional DC/DC converter, and inverter. Operation of this system can be described in terms of two modes. In the daytime, the solar panel absorbs energy from sun light; the DC/DC converter boosts the voltage to a certain value and charges the battery pack. During the nighttime, the battery pack provides energy to the circuit; the DC/DC converter boosts voltage level and the inverter inverts DC voltage to single phase AC voltage; this output of 110V AC voltage can charge cell phones, run an energy save lamp, a fan, or even power a laptop. Details of the design process, system operation, components used in the system, simulation and experimental results are explained in the thesis. The main contribution of the thesis is the development of a new off-grid solar powered energy storage system control strategy that can store solar energy in the battery and provide regular 110V AC xii voltage output to the load when needed; additionally, the implementation of the concept along with testing on an experimental set-up is discussed.
M.S. in Electrical Engineering, December 2012
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Title: Informal Learning with Twitter
Creator: Wilhelm, Eva C.
Date: 2011-04-25, 2011-05
Description: Twitter use has evolved from status updates to a broad range of uses from personal broadcasting to information sharing and conversations. A...
Show moreTwitter use has evolved from status updates to a broad range of uses from personal broadcasting to information sharing and conversations. A study was conducted to determine how Twitter is used for informal learning purposes. It was examined what kind of questions with a learning objective are asked, and under which circumstances these questions are answered. Questions were categorized according to question topic, type, structure and audience. According to the analysis, users most frequently asked for definitions and procedural information about technology, web, software and Twitter use. The questions with the highest answer rate were questions directed at individual users via @replies, and asked about definitions and other factual information.
M.S. in Technical Communication and Informational Design, May 2011
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Title: LENGTH DEPENDENT ACTIVATION IN MANDUCA SEXTA FLIGHT MUSCLE
Creator: Kumar, Mohit
Date: 2011-08-09, 2011-07
Description: The flight muscle of Manduca sexta has some interesting properties. It is synchronous, like mammalian skeletal and cardiac striated muscle,...
Show moreThe flight muscle of Manduca sexta has some interesting properties. It is synchronous, like mammalian skeletal and cardiac striated muscle, but it is structurally similar to the more widely studied asynchronous insect flight muscles of Drosophila and Lethocerus. One of the main goals of the thesis is to generate a useful skinned preparation for mechanical studies in vitro. A number of different skinning protocols were tried and evaluated for preservation of structural integrity by using light and X-ray diffraction. In all muscles studied to date, isometric force is a function of the [Ca2+] of the bathing solution and also a function of the sarcomere length whereby more force is generated at a longer sarcomere length than at a shorter for the same [Ca2+]. This phenomenon is termed “length dependent activation” (LDA). To date no real studies on the force-pCa relationship has been done on Manduca sexta flight muscle. This force-pCa analysis would give us some insight into the length dependent activation (LDA) in this novel insect flight muscle system. The present studies were undertaken to characterize and analyze the force-pCa relationships in Manduca sexta. Conditions were found that allowed skinning muscles while maintaining good structural order. We found that both DLMs dorsal and ventral show length-dependent activation at longer SL. Our study also shows that ventral muscles are more cooperative than the dorsal muscles which may be related to their different functions in vivo.
M.S. in Biological, Chemical, and Physical Sciences, July 2011
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Title: BICYCLE CRASH ANALYSIS IN CHICAGO
Creator: Van Nortwick, Taylor Wade
Date: 2013, 2013-07
Description: The United States is making big plans for improvements in bicycle infrastructure. To best understand if the improvements will be successful in...
Show moreThe United States is making big plans for improvements in bicycle infrastructure. To best understand if the improvements will be successful in creating a safe network, a study was done to determine contributing factors in bicycle crashes. Bicycle and motor vehicle crash data from around Chicago between 2005 and 2011 was analyzed for significant factors in infrastructure, cyclist and motorist attributes. Temperature was used as a predictor of bicycle traffic due to the seasonality of bicycling in Chicago. It was found that more bicycles and vehicles result in higher crash rates. It was also found that on -street parallel parking, signalized, skewed and multiple legged intersections lead to higher crash rates.
M.S. in Civil Engineering, July 2013
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Title: COORDINATE-EXCHANGE ALGORITHM CONSTRUCTION OF UNIFORM SPACE FILLING DESIGN
Creator: Han, Shipeng
Date: 2014, 2014-05
Description: Many scientific phenomena are now investigated by complex computer models. A computer experiment is a sequence of runs with various inputs....
Show moreMany scientific phenomena are now investigated by complex computer models. A computer experiment is a sequence of runs with various inputs. The uniform experimental design seeks its design points to be uniformly scattered on the experimental domain and is one kind of a space-filling design that can be used for computer experiments and OK for industrial experiments. The coordinate-exchange method we use is one-dimensional constrained optimization, searching for the optimal coordinate to make the points filling the space uniformly. This method saves large amounts of calculation compared to the multivariate optimization problems. In this thesis we provide the coordinate-exchange algorithm and demonstrate our methodology with numerical examples. Key words: Coordinate-exchange, Uniform design, Computer experiment, Space-filling design, optimal design.
M.S. in Applied Mathematics, May 2014
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Title: NATURAL GAS STORAGE EVALUATION FOR GAS FIRED POWER PLANT OPERATION
Creator: Nan, Sibo
Date: 2014, 2014-12
Description: Gas generation has been the preferred non-renewable generation technology during the last few years due to its high efficiency, low emission,...
Show moreGas generation has been the preferred non-renewable generation technology during the last few years due to its high efficiency, low emission, and good flexibility. As a result of increasing gas usage by gas fired power plant (GFPP), gas pipeline congestion becomes a big issue for GFPP. As non-electric natural gas consumers have higher priority in pipeline capacity usage, GFPP’s profit could be negatively impacted when non-electric gas consumption is extremely high. Natural gas storage directly connected to GFPP can supply gas when pipeline capacity is constrained. This thesis presents a model of evaluating the benefit of gas storage to GFPP. The model is formulated as a mixed-integer quadratic programming (MIQP) problem and solved using a commercial MIQP solver. A case study on one GFPP owning 4 natural gas generators is performed based on this model. It is observed that GFPP with gas storage directly connected can make more profit than GFPP without storage. A sensitivity study is conducted to analyze the relationship between the optimal gas storage capacity, as well as GFPP profit, and electricity price, non-electric gas consumption, and gas pipeline contract price. It is observed that the optimal gas storage capacity increases when electricity price increases and available pipeline capacity declines; however it does not change with the variation of gas pipeline contract price. It is also observed that the maximum profit of GFPP is most sensitive to electricity price, then non-electric gas consumption, and is least sensitive to gas pipeline contract price. The main application of this model is to help GFPP owner determine whether or not to install gas storage and, if yes, what the optimal capacity of gas storage should be. In addition, this model can also help GFPP owner plan gas purchase and gas pipeline capacity contract volume.
M.S. in Electrical Engineering, December 2014
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Title: THE ELASTICITY AND PURIFICATION OF THE FLIGHT MUSCLE PROTEINS OF MENDUCA SEXTA
Creator: Dong, Sicong
Date: 2014, 2014-05
Description: Contraction of the DLM1 flight muscles of the Hawmoth, Manduca sexta are synchronous with the nervous impulse stimulation like mammalian...
Show moreContraction of the DLM1 flight muscles of the Hawmoth, Manduca sexta are synchronous with the nervous impulse stimulation like mammalian skeletal muscle. With cardiac-like behavior, DLM1 muscle of Manduca sexta can be a useful model to resemble mammalian cardiac muscle. Asynchronous flight muscles, like Lethocerus and Drosophila flight muscle, can only extend a few percent. But Manduca flight muscle has the ability to extend at least 100% in vitro and 9% in vivo. Very little is known about the protein composition and physiological behavior of Manduca flight muscle. Hence the length-tension behaviors of the DLM1 muscle of Manduca sexta are of considerable interest. In this experiment, we used PPi to remove thick filament in the sarcomere and focus on the passive tension generated by elastic proteins (projectin, kettin and sls proteins) in the sarcomere. The results showed elastic proteins (projectin, kettin and sls proteins)-based passive tension play a major role on muscle passive force in DLM1 muscles of Manduca sexta. We also tested a new way to prepare chemically skinned muscle samples where the dorsal and ventral muscle samples are pinned still in their shell on plates during the skinning step. In addition, preliminary experiments attempting to purify the DLM1 muscle proteins of Manduca sexta, fast protein liquid chromatography was used. Then 1% vertical SDS-agarose gel electrophoresis (VAGE) and 4-20% SDSPAGE gel are used to detect the samples after purification. We successfully purified 900kDa projectin and 700kDa kettin, which are major elastic proteins and useful for further research.
M.S. in Biology, May 2014
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Title: MEAN EXIT TIME FOR RADIALLY SYMMETRICAL DYNAMICAL SYSTEMS DRIVEN
Creator: Luan, Yuanchao
Date: 2013, 2013-12
Description: Stochastic differential equations (SDEs) driven by non-Gaussian L´evy noises have attracted much attention recently [1, 29]. In [12], the...
Show moreStochastic differential equations (SDEs) driven by non-Gaussian L´evy noises have attracted much attention recently [1, 29]. In [12], the authors studied a scalar SDE driven by a non-Gaussian L´evy motion, and numerically investigate mean exit time and escape probability for arbitrary noise intensity in one dimensional case. In the present thesis, we utilize a different strategy to explore a numerical method for the problem in two dimensional cases. To be specific, we assume the solution u(x) is radially symmetric with respect to the origin, and then represent the equation using radial coordinate, reducing the problem into one dimensional case. Then main difficulty is that, in the integral term, appears a Gauss Hypergeometric function and the unknown function u(r), which makes the error estimates complicated. We exploit some properties of Gauss Hypergeometric function, and finally make out a way for estimating the error [19]. Up to now we are only able to deal with this problem with 0 < α ≤ 1, since our numerical scheme does not converge when 1 < α < 2. Then we compare our numerical solutions with the analytical ones which are given in [3], and they coincide very well. KeyWords: Stochastic dynamical systems; non-Gaussian L´evy motion; L´evy jump measure; First exit time
M.S. in Applied Mathematics, December 2013
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Title: ANALYSIS OF VARIATION IN MULTISTAGE MANUFACTURING PROCESS BASED ON TREE REGRESSION
Creator: Chen, Zhefu
Date: 2014, 2014-05
Description: In a multistage manufacturing process, variation propagates in the process when we produce products from stage to stage. Since there are...
Show moreIn a multistage manufacturing process, variation propagates in the process when we produce products from stage to stage. Since there are limits of reducing variation through process in traditional industrial management and it is hard to monitor the process when the engineering domain knowledge is insufficient. We investigated statistical methods based on piecewise tree regression model including: CART, Bayesian CART, Bayesian treed linear model and Bayesian treed Gaussian process to multistage manufacturing process. The difference performances between models were discussed in a wafer manufacturing process case as a result comparison. Key Words: Multistage process, variation propagation, process monitoring, piecewise tree regression
M.S. in Applied Mathematics, May 2014
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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: REAL TIME STATIC SCENE 3D RECONSTRUCTION USING DEPTH SENSORS FOR AUGMENTED TELEOPERATION
Creator: Srinivasan, Ranga Ramanujam
Date: 2015, 2015-05
Description: In the first part of this Master’s Thesis, literature survey is done to find the best performing algorithm in terms of real-time performance...
Show moreIn the first part of this Master’s Thesis, literature survey is done to find the best performing algorithm in terms of real-time performance and quality of 3D reconstruction from depth images. Kinfu of PCL is found to be the best in terms of real-time performance and maintainability, as it is open-source software, with thousands of users working on to improve it. The primary part of the thesis is to improve on the 3D reconstruction quality of Kinfu and this is achieved by improving on the three important stages of Kinfu, Depth Filtering, Pose-estimation and 3D reconstruction. A new Anisotropic depth filtering kernel is proposed and it is found to give 23% quantitative improvement over baseline Kinfu. A modified pose-estimation which incorporates the uncertainty or error characteristics of the depth measured as part of the ICP algorithm is proposed. This results in a 51% quantitative improvement and a big subjective quality improvement over baseline Kinfu. A similar approach based on depth error characteristics but applied to 3D reconstruction stage which is based on an already published paper [1], is implemented. All the improvements in each of the three stages are combined together, to get a robust, real-time 3D reconstruction framework.
M.S. in Electrical Engineering, May 2015
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Title: Garfield Station Area Rehabilitation Project
Creator: Oh, Soohyun
Date: 2011-04-25, 2011-05
Description: Architecture is significantly associated with people. Because architecture is design of life, activities and spaces for people. Therefore,...
Show moreArchitecture is significantly associated with people. Because architecture is design of life, activities and spaces for people. Therefore, architectural behavior does not have only a physical impact but also social and economic impact on the area. Especially the architectural elements can help to development an area and provide an enhanced economic aspect, cultural activities and social communication to inhabitants in underdeveloped or backward area. The Garfield Station Area Rehabilitation Project is a grand scale development project that comprehends urban scheme, site master plan and architectural design phases. The goal of the project, consistent throughout all phases, is to transform the abandoned Washington Park Community into a recovered, preserved and developed community with its rich history by promoting cultural, social and economical incentives to be linked to the Hyde Park Community.
M.S. in Architecture, May 2011
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Title: SECURITY-CONSTRAINED UNIT COMMITMENT RESERVE DETERMINATION IN JOINT ENERGY AND ANCILLARY SERVICES AUCTION
Creator: Ganji Tanha, Mohammad Mahdi
Date: 2012-07-25, 2012-07
Description: This study presents the method in which the energy and ancillary services auction is simultaneously cleared in electricity market. By the...
Show moreThis study presents the method in which the energy and ancillary services auction is simultaneously cleared in electricity market. By the security-constraint unit commitment model proposed in this study Independent System Operators (ISO) can determines the sufficient amount of reserve which is necessary to maintain security and reliability of the system. Before the fixed reserve requirement either equal to a percentage of the system peak load or a thermal unit with highest capacity is considered in energy and ancillary service auction in market clearing. The disadvantage of this method is high cost and insufficiency. When it is insufficient the system operator needs to committee more thermal units or does the load curtailment. At the time the fixed quantity is more than needed customers pay more although it is not necessary. Here the sufficient amount of reserve is determined based on the contingency which has been simulated. Contingencies include thermal unit outage and line outage is considered. The amount of reserves is obtained based on thermal units’ physical constraints and the rate offered in the electricity market. Then the integration of wind generation and its effects on the quantity of the reserve determination is considered. Since the wind power generation brings uncertainties to the power system we need to consider scenarios. In order to generate wind power generation scenarios we use Monte Carlo simulation. Since the number of scenarios are too much and increase the problem complexity we use Fast backward/forward scenario reduction. This problem is solved through direct optimization problem including the minimization of the operational cost as well as satisfying the network security constraints when contingency happens.
M.S. in Electrical Engineering, July 2012
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Title: DISPARITY ESTIMATION WITH SEGMENT-BASED MULTI-STEP DISPARITY REFINEMENT
Creator: Anand, Bhaskar
Date: 2012-07-20, 2012-07
Description: Stereo Vision is one of the fundamental problems of computer vision and one of the oldest and heavily investigated areas of 3D Vision. Recent...
Show moreStereo Vision is one of the fundamental problems of computer vision and one of the oldest and heavily investigated areas of 3D Vision. Recent advances in stereo matching methodologies have allowed researchers to develop several stereo vision techniques. But it has been observed that most of these methodologies mainly focus on only one aspect, either the execution time or the quality of the generated depth map. While attempts to maximize the quality of the depth map have been successfully achieved, it is however observed that the execution time has increased signi cantly, thereby rendering them un t for real time implementation. In this thesis, an attempt to solve the above said problem is presented, in which we combine the e ects of two important stereo matching concepts, one attempting to increase the depth map quality, while the other being that of having an algorithmic structure so that in future, it can be used for real-time implementation. By applying hardware-friendly methods to the framework of segment based stereo matching, the method is said to achieve a good quality depth map. This work also discusses the various challenges which it takes care of plus the study of performance compared to existing methods.
M.S. in Electronical Engineering, July 2012
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Title: PEGYLATION OF FIBRONECTIN AND ITS FUNCTIONAL DOMAINS: EFFECT ON STABILITY AND BIOLOGICAL ACTIVITY
Creator: Zhang, Chen
Date: 2013, 2013-07
Description: Delayed wound healing in many chronic wounds has been linked to the lack of extracellular matrix (ECM) support and the degradation of...
Show moreDelayed wound healing in many chronic wounds has been linked to the lack of extracellular matrix (ECM) support and the degradation of fibronectin (FN) by an abnormally high protease level. The ECM is important in wound healing because it provides physical and chemical cues that direct tissue growth and development. FN is a key ECM protein that attracts and binds different molecules and cells and thereby supports biological responses associated with wound healing. The goal of my study is two fold: (1) To create an ECM analogue based on a composite of polyethylene glycol (PEG) hydrogels and FN binding domains and (2) To stabilize FN against proteolytic degradation by conjugating it to PEG. To address the first goal, I used Michael addition chemistry to covalently link the cell-binding domain of FN, III9−10, to PEG diacrylate and cross-linked the conjugate to PEG hydrogels. The conjugation of PEG to III9−10 was through cysteines in the affinity tag Glutathione S Transferase (GST). The conjugate of GST-III9−10 and PEG was characterized by: (i) Circular dichroism studies to determine secondary structure, (ii) Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) to determine molecular weight, and (iii) Ellmans reagent to determine the efficiency of PEG conjugation to GST-III9−10. The conjugate of PEG and GST-III9−10 had comparable secondary structure to GST-III9−10. SDS-PAGE studies showed that up to three PEG molecules were attached to one GST-III9−10 molecule. The efficiency of PEG conjugation was greater than 90% and occurred within 30 minutes after PEG diacrylate addition. Adhesion assays were used as a metric of biological activity. These assays demonstrated that on a molar basis cell adhesion and spreading were significantly higher on PEG hydrogels with GST-III9−10 than those with the commonly used arginine-glycine-aspartic acid (RGD) peptide. Scaffold rigidity is an important biological cues that influence xi cell responses. However, a comparative study of rigidity on GST-III9−10 and RGD functionalized PEG hydrogels demonstrated that differences in rigidity could not account for differences in cell adhesion and spreading between RGD and GST-III9−10 functionalized PEG hydrogels. Thus as ECM analogues, GST-III9−10 functionalized hydrogels provide more robust biochemical cues than RGD functionalized hydrogels. Studies of PEG hydrogel composites with mixtures of III9−10 and a fibronectin binding domain demonstrated that biological responses of adhesion and spreading and extracellular matrix assembly could be controlled by varying the ratio of these two domains and the rigidity of the PEG hydrogels. FN was stabilized against proteolytic degradation by covalent attaching it to PEG or by PEGylating it. FN was first isolated from human plasma by gelatin affinity chromatography and then PEGylated using two methods. The first method is to PEGylate human plasma fibronectin (HPFN) at cysteine residues with 3.4 kDa PEG diacrylate. The second method is to PEGylate HPFN at lysine residues on the surface with 2-10 kDa PEG Succinimidyl carboxy methyl esters. Cysteine PEGylation of HPFN was first carried out because cysteines are concentrated in the amino- terminus of HPFN which leaves two-thirds of the molecule, including the cell-binding domain, unperturbed. PEGylation of HPFN on cysteines resulted in a molecule that supported cell adhesion, spreading, focal adhesion formation and cell migration in a comparable manner to native HPFN. Moreover, PEGylated HPFN was incorporated into the ECM in a similar manner to native HPFN when present in the culture media but not when coated on a surface indicating that PEGylation on cysteines modified some biological activity of HPFN. Additionally, HPFN PEGylated by this manner could not bind denatured collagen or gelatin. The gelatin-binding domain is at the site of cysteine PEGylation. The second approach for PEGylation of HPFN was through lysine residues xii on the surface of the protein. This approach was used because it targeted different amino acid residues in FN. The length of PEG and extent of PEGylation have been reported to influence biological activity of proteins. In the second approach, both PEG length and extent were varied. HPFN completely PEGylated on lysines residues was significantly more proteolytically stable than native HPFN but had reduced cell attachment and spreading. Furthermore, cell spreading and attachment on surfaces conjugated with this lysine PEGylated HPFN decreased with increasing PEG length. Partially PEGylated HPFN was synthesized by masking the cell and gelatin binding domains during PEGylation. The partially PEGylated HPFN supported cell adhesion and spreading in a similar manner to native HPFN and was more proteolytically stable. For the partially PEGylated HPFN, the size of PEG poly had no significant influence on the attachment and spreading of cells. These studies are the first attempt by any laboratory to stabilize FN against proteolytic degradation while retaining activity and show the feasibility of this approach as a potential therapeutic approach. The work presented here shows a two-prong approach by which the problem of ECM degradation and deficiency chronic wound healing can be addressed. The first approach for addressing ECM deficiency is through a scaffold design methodology. The novelty of the scaffold approach is that it uses the cell-binding domains of FN instead of the often-used RGD peptide. I demonstrate that a PEG hydrogel with the cell-binding domain produces a more robust biological response in cells than a PEG hydrogel with the RGD peptide. I also demonstrate that varying different functional domains of fibronectin can be used to controllably stimulate multiple biological responses. The second approach demonstrates a method by which FN, a key ECM protein, is stabilized against proteolytic degradation without perturbing its activity. These studies of creating PEG-FN conjugates are the first of their kind. Collectively, the data that I present in this thesis will lead to novel therapeutic methods for treating chronic wounds.
PH.D in Chemical Engineering, December 2012
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Title: MODELING THE PERFORMANCE OF A SOLAR CHIMNEY WITH BUILT-IN PHASE CHANGE MATERIALS TO IMPROVE NATURAL VENTILATION
Creator: Khorraminejad, Aysan
Date: 2014, 2014-12
Description: The use of solar chimneys to improve natural ventilation in buildings has been shown to yield energy savings while maintaining thermal comfort...
Show moreThe use of solar chimneys to improve natural ventilation in buildings has been shown to yield energy savings while maintaining thermal comfort in some climate zones. However, one disadvantage is that the ability to control passive ventilation with solar chimneys is often limited by temporal variations of building function and diurnal weather patterns. The unique thermal properties of phase change materials (PCMs) may provide opportunities to manage some of the limitations of solar chimney strategies in buildings through the timed storage and release of thermal energy, which can aid in minimizing daytime heat gains and increasing the effectiveness of nighttime flushing by natural ventilation. This work explores the potential of PCMs combined with solar chimneys to support the passive ventilation of buildings using whole building energy simulation. Results are intended to inform architects and engineers on best practices for incorporating PCMs in buildings with solar chimneys. A model of a prototype office building designed to ASHRAE Standard 90.1 was developed in EnergyPlus and investigated in five U.S. climate zones. A total of 1023 energy simulations were performed to address the following research questions: (1) In what U.S. climate zone is the use of PCMs most appropriate? (2) Can PCMs improve night flushing ventilation when used with a solar chimney? (3) What are the optimal locations for installation of PCMs in building and solar chimney construction in order to provide optimal cooling load reductions? and (4) How do PCM properties influence cooling load reductions? Results demonstrate that the solidification and melting process of PCMs can indeed be used to prolong natural ventilation for night flushing in the evening and nighttime, particularly in climate zones with large diurnal outdoor temperature fluctuations. Results also suggest the following: (1) the optimal location for installation of PCMs in most climates is within the structure of south-facing envelope assemblies; (2) the PCM melting temperature should be equal to or greater than the zone set point temperature; (3) thicker PCMs can yield slightly more cooling energy savings than thinner PCMs; and (4) the thermal conductivity of PCMs does not appear to have a substantial influence on performance.
Ph.D. in Architecture, December 2014
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