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Title: ACTION RECOGNITION USING SPATIO-TEMPORAL FEATURE EXTRACTION
Creator: Mesmakhosroshahi, Maral
Date: 2012-04-24, 2012-05
Description: The importance of automatically recognition of human activities and it's ap- plications increase as the technology is growing fast these days....
Show moreThe importance of automatically recognition of human activities and it's ap- plications increase as the technology is growing fast these days. In this thesis we focus on the action recognition techniques using 3D feature extraction techniques and try to improve the performance of the available feature extraction methods to have more accurate action classi cation. This thesis is based on spatio-temporal feature extraction techniques that can be extension of two dimensional feature extractions. At rst, 3D corner detector and 3D blob detector, two popular interest point detectors that successfully extended to spatio-temporal domain are reviewed. 3D corner detector is an extension of Harris corner detector which is proposed for corner detection in space-time and 3D blob detector is the 3D version of Hessian blob detector. A method is proposed to improve the robustness of 3D corner detectors against illumination variances based on the application of sigmoid function in contrast stretching. These interest points need to be described by feature vectors. In this part also a review on the SIFT descriptor and it's 3D extension is done. Another 3D feature descriptor discussed in this thesis is Cuboid. In the feature description part a new method is proposed based on the 3D SIFT feature descriptor by changing the binning method of the gradient orientation histogram to a non-uniform binning scheme. Using these non-uniform bins increases the accuracy of action classi cation by focusing on the areas near the interest points. Action classi cation is done using bag of features and supervised learning techniques. For making a dictionary of features, feature vectors are clustered by K-means clustering method and support vector machine is used for classi cation of human activities.
M.S. in Electrical Engineering, May 2012
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Title: COVERAGE AND CONNECTIVITY IN WIRELESS NETWORKS
Creator: Xu, Xiaohua
Date: 2012-04-25, 2012-05
Description: The limited energy resources, instability, and lacking central control in wireless networks motivates the study of connected dominating set ...
Show moreThe limited energy resources, instability, and lacking central control in wireless networks motivates the study of connected dominating set (CDS) which serves as rout- ing backbone to support service discovery, and area monitoring and also broadcasting. The construction of CDS involves both coverage and connectivity. We ¯rst study sev- eral problems related to coverage. Given are a set of nodes and targets in a plane, the problem Minimum Wireless Cover (MWC) seeks the fewest nodes to cover the targets. If all nodes are associated with some positive prices, the problem Cheapest Wireless Cover (CWC) seeks a cheapest set of nodes to cover the targets. If all nodes have bounded lives, the problem Max-Life Wireless Cover (MLWC) seeks wireless coverage schedule of maximum life subject to the life constraints of individ- ual nodes. We present a polynomial time approximation scheme (PTAS) for MWC, and two randomized approximation algorithms for CWC and MLWC respectively. Given a node-weighted graph, the problem Minimum-Weighted Dominating Set (MWDS) is to ¯nd a minimum-weighted vertex subset such that, for any vertex, it is contained in this subset or it has a neighbor contained in this set. We will propose a (4+²)-approximation algorithm for MWDS in unit disk graphs. Meanwhile, for the connecting part, given a node-weighted connected graph and a subset of terminals, the problem Node-Weighted Steiner Tree (NWST) seeks a lightest tree connecting a given set of terminals in a node-weighted graph. We present three approximation algorithms for NWST restricted to UDGs. This dissertation also explores the applications of CDS, and develops e±cient algorithms for the applications such as real-time aggregation scheduling in wireless networks. Given a set of periodic aggregation queries, each query has its own period , and the subset of source nodes Si containing the data, we ¯rst propose a family of e±cient and e®ective real-time scheduling protocols that can answer every job of each query task within a relative delay under resource constraints by addressing the following tightly coupled tasks: routing, transmission plan constructions, node activity scheduling, and packet scheduling. Based on our protocol design, we further propose schedulability test schemes to e±ciently and e®ectively test whether, for a set of queries, each query job can be ¯nished within a ¯nite delay. We also conduct extensive simulations to validate the proposed protocol and evaluate its practical performance. The simulations corroborate our theoretical analysis.
Ph.D. in Computer Science, May 2012
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Title: LOG ANALYSIS FOR RELIABILITY MANAGEMENT IN LARGE-SCALE SYSTEMS
Creator: Zheng, Ziming
Date: 2012-07-16, 2012-07
Description: With the increasing scale and complexity of high performance computing (HPC) systems, reliability management is becoming a major concern....
Show moreWith the increasing scale and complexity of high performance computing (HPC) systems, reliability management is becoming a major concern. System logs are the primary source of information to understand and analyze system problems. Nevertheless, manual log processing is time-consuming, error-prone, and not scalable. Currently little study has been done on automated log analysis for practical use in HPC systems. In this thesis, we present a log analysis infrastructure by exploiting data mining and machine learning technologies. Our work can be broadly divided into four parts: log pre-processing, online failure prediction, automatic root cause diagnosis, and reliability modeling. We evaluate our results by means of system logs collected from production HPC systems. This work can greatly improve our understanding of faults and failures arising from hardware/software components and their interactions. It can further facilitate the reliability management for HPC systems.
Ph.D. in Computer Science, July 2012
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Title: PERFORMANCE ANALYSIS AND OPTIMIZATION OF LARGE-SCALE SCIENTIFIC APPLICATIONS
Creator: Wu, Jingjin
Date: 2013, 2013-07
Description: Scientific applications are critical for solving complex problems in many areas of research, and often require a large amount of computing...
Show moreScientific applications are critical for solving complex problems in many areas of research, and often require a large amount of computing resources in terms of both runtime and memory. Massively parallel supercomputers with ever increasing computing power are being built to satisfy the need of large-scale scientific applications. With the advent of petascale era, there is an enlarged gap between the computing power of supercomputers and the parallel scalability of many applications. To take full advantage of the massive parallelism of supercomputers, it is indispensable to improve the scalability of large-scale scientific applications through performance analysis and optimization. This thesis work is motivated by cell-based AMR (Adaptive Mesh Refinement) cosmology simulations, in particular, the Adaptive Refinement Tree (ART) application. Performance analysis is performed to identify its scaling bottleneck, a performance emulator is designed for efficient evaluation of different load balancing schemes, and topology mapping strategies are explored for performance improvements. More importantly, the exploration of topology mapping mechanisms leads to a generic methodology for network and multicore aware topology mapping, and a set of efficient mapping algorithms for popular topologies. These have been implemented in a topology mapping library – TOPOMap, which can be used to support MPI topology functions.
PH.D in Computer Science, July 2013
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Title: A CONCEPTUAL SOLAR CHIMNEY PLANT AND FLORAL FARM USING ETFE AND BAMBOO
Creator: De Vita, Niels
Date: 2012-11-20, 2012-12
Description: Motivated by a desire to create an architectural response to the environmental and social challenges of today, the following thesis project...
Show moreMotivated by a desire to create an architectural response to the environmental and social challenges of today, the following thesis project attempts to offer new paths for the future development of the solar chimney energy plant concept originally developed by the German engineer Jӧrg Schlaich in the early 1980s. The starting point of this thesis was to analyze the solar chimney prototype completed in the Manzanares desert in 1982 in order to understand the parameters guiding the design. The analysis allowed me to better understand the potential of the concept and to recognize the opportunity that existed to push the technological boundaries to craft a new design that reflects the current socio-political, economical and environmental context we live in. In the following pages, I attempt to demonstrate that the concept could be made even more appealing through the use of technology and locally available resources. By doing this, I seek to reinvigorate the idea, opening paths for a new conversation about the potential of the project as a social agent for progress. Throughout this thesis, I remain respectful and aware of the accomplishments of the pioneers before me, simply taking cues from their work to suggest new alternatives and solutions to a problem that has been made even more pressing due to the world’s energy crisis and economic uncertainty.
M.S. in Architecture, December 2012
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Title: IMPROVEMENT OF BUS TRANSIT OPERATIONS BY MINIMIZING NON-REVENUE TRAVEL TIME
Creator: Arthur, Christina
Date: 2012-06-04, 2012-07
Description: There are many activities in which a transit agency can investigate reduce costs. Three main activities include service cuts, renegotiations...
Show moreThere are many activities in which a transit agency can investigate reduce costs. Three main activities include service cuts, renegotiations of union labor contracts and modifications to bus operations. The first activity, cutting service, is often a last resort because not only must an agency adhere to its budget but also its service standards. Service cutting can involve route eliminations, stop eliminations, reroutes and reductions in spans of service and frequency of service. These service cuts greatly impact the riders in which routes serve as well as the image of the agency. In order to maintain customer satisfaction and ridership, an agency may decide to employ the latter two activities. In essence these two types of activities, singularly or in combination, can produce a reduction in overhead costs to the agency by more efficiently operating services. This paper focuses on modifications to bus operations as it relates to pull-in and pull-out trips, commonly referred to as deadheading and operator travel to relief points. Using the urban bus operation of the Chicago Transit Authority, a model is developed to assign routes to garages given the locations of the pull-in and pull-out locations associated with each route. As the system currently exists, there are seven garages distributed across the city from which 144 bus routes start and end. Many of these routes are operated out of multiple garages. The main reason for these route-to-multi-garage assignments is garage capacity and scheduling needs. The goal of this research is to determine how routes can be assigned to one specific garage and still meet the requirements given by the schedule.
M.S. in Civil Engineering, July 2012
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Title: DYNAMICS OF A THREE-DIMENSIONAL FOUR-BAR LINKAGE SUBJECT TO RANDOM EXTERNAL FORCING
Creator: Lytell, Mark R.
Date: 2011-11-15, 2011-12
Description: This thesis explores the dynamics of a three-dimensional four-bar mechanical linkage subject to random external forcing. The Lagrangian...
Show moreThis thesis explores the dynamics of a three-dimensional four-bar mechanical linkage subject to random external forcing. The Lagrangian formulation of the equations of motion are index-3 stochastic di erential-algebraic equations (SDAE) that describe the time evolution of the sample paths of the generalized coordinates, velocities, and Lagrange multipliers as stochastic processes. We solve the SDAEs using two di erent approaches: inverse dynamics, Case Study 1, via independent, successive solution of the nonlinear equations for each kinematic variable, where the time evolution of one generalized coordinate is prescribed; and direct dynamics, Case Study 2, via direct solution of the SDAEs in the index-1 formulation, using fourth-order stochastic backward di erentiation formula (BDF) with modi ed Newton iteration and position and velocity stabilization (Ascher and Petzold [2]), where the (deterministic) input driving torque is prescribed. For the particular application of a three-dimensional swing gate security system, we conduct numerical experiments for both approaches. In Case Study 1, we simulate the random external forcing as a Gaussian wind speed process that applies stochastic wind drag onto the gate. The kinematic variables are deterministic, while the required input driving torque is a stochastic process. In Case Study 2, we apply the external forcing as a resistive torque with additive Gaussian noise modeling the wind drag; the kinematic variables are stochastic processes. For both cases, we apply four mean wind speeds: 0 mph (deterministic only), 10 mph, 20 mph, and 30 mph, from which we compute the deterministic solution and three stochastic sample paths for each stochastic process. The overall conclusions are that direct solution is possible for inverse dynamics, that the solution of index-1 SDAEs in multibody dynamics is tractable since the mass matrix is symmetric and positive de nite, and that the deterministic solution is the expectation of the sample paths.
M.S. in Applied Mathematics, December 2011
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Title: PHYSICS-PRESERVING FINITE DIFFERENCE SCHEMES FOR THE POISSON-NERNST-PLANCK EQUATIONS
Creator: Flavell, Allen
Date: 2014, 2014-07
Description: The Poisson-Nernst-Planck equations are a system of nonlinear di erential equations that describe ow of charged particles in solution. This...
Show moreThe Poisson-Nernst-Planck equations are a system of nonlinear di erential equations that describe ow of charged particles in solution. This dissertation is about the design of numerical schemes to solve this system which preserves global properties exhibited by the system. There are two major advances presented. The rst is the design of schemes that conserve mass globally when the system is coupled with no- ux boundary conditions. Most notably, a scheme using central di erencing and TR-BDF2 achieves second order accuracy in both space and time, while also conserving global mass is presented. The second is the design of a more general scheme that preserves the time-varying properties of the free energy of the system. One such a scheme uses central di erencing in space and trapezoidal integration in time to achieve second order accuracy in both space and time, while also preserving the energy dynamics, but at the cost of requiring positivity of the solution. There is also a discussion of solution methods: the classic Newton iteration scheme is compared with a modi ed Gummel iteration scheme for the purpose of solving the transient equations. The intended application of this work is the modeling of ion channels, and many of the simulations presented use parameters consistent with models of ion channels.
Ph.D. in Applied Mathematics, July 2014
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Title: VIBRATION IN TRACTION MOTORS FOR ELECTRIC AND HYBRID ELECTRIC VEHICLES
Creator: Yang, Zhi
Date: 2014, 2014-12
Description: Due to increased fuel efficiency and lower cost/mile feature, electric vehicle (EV) and hybrid electric vehicle (HEV) are becoming more and...
Show moreDue to increased fuel efficiency and lower cost/mile feature, electric vehicle (EV) and hybrid electric vehicle (HEV) are becoming more and more popular. It is estimated that the sale of electric vehicles will reach 3.8 million by 2020, while hybrid vehicles will grow to 4% by 2020 from their current share of 2%. To meet this target, EV an HEV motors, the core energy conversion components, should not only satisfy specific requirements in performance and efficiency but also constrain vibration. This necessitates the analysis of vibration in traction motors for EV/HEV application. The primary objective of this dissertation is to characterize and compare the electromagnetic and vibrational behavior of typical traction motors (PMSM with distributed winding, PMSM with concentrated winding, IM, and SRM) over a wide torque speed range. For this purpose, weak-coupled analysis of electromagnetic force and structure are performed in ANSYS environment. The secondary aim of this dissertation is to develop a rotor position related variable switching frequency pulse width modulated (PWM) strategy to ameliorate the acoustic noise due to high frequency harmonic current. Switching frequency is modified online to adapt current ripple and vibration requirement, thus ameliorate the acoustic noise. It is expected that this strategy with variable switching frequency has the advantages of spreading the vibration spectrum and reducing switching losses. Experimentally verification is also performed. At the end of this dissertation, characterization of vibration behavior of switch reluctance machine with higher number of rotor poles than stator poles is performed.
Ph.D. in Electrical and Computer Engineering, December 2014
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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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